Intro to Methyl Chloride Plant 1

Methyl Chlorine Plant 1 Instruction ManualMethyl ChlorideProduction:General:Methyl Chloride is a solvent or Chemical Reagent (e.g. use as an alkylatingagent). It is also used as a refrigerant.Generally methyl chloride is a gas under atmospheric pressure andambient temperature (30 C). Some of its characteristics are:Chemical FormulaMolecular WeightMelting PointBoiling PointColourFlammabilityFlammable LimitOdourSolubulityHealth Hazard

CH3Cl50.49-97.7-23.8Gas : colourlessLiquid: transparentFlammable gasLower: 10.7 % in airUpper: 17.4% in airFaintly sweetSoluble in water; very solublein alcohol, chloroform, mineral oils etcThreshold limit: 100 ppm

Methyl Chloride can be produced in the following process:a) Direct chlorination of methane gasb) Reaction of gaseous HCl and vapour methanolFor our process, we produce it by the reaction of gaseous HCl andvaporized methanol. One of the raw material for the above process, i.e.hydrochloric acid, is readily available from our existing Chloro-Soda plant.Introduction to the ProcessMethyl Chloride (CH3Cl) is produced by combination of gaseous HCl andvapour methanol in a glass-lined reactor (G100) using zinc chloridesolution as the reaction catalyst. Thus,ZnCl2

CH3OH + HCl

CH3Cl + H2O + h145 C

The reaction is exothermic i.e. heat h is generated.

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For the same reactor and at the same reaction conditions andconsequences, Methyl Oxide formation (CH3 O CH3) through methanolown molecules reaction also take place as side reaction is:ZnCl2

CH3OH + CH3OH

145 C

CH3OCH3 + H20

The side reaction can be suppressed to a very small extent (only 0.1%) byan excess HCl atmosphere in the reactor. The most economic and optimalHCL excess is 25% more than what requires for the reaction.The products which is then coming out from the reactor is called thecrude products which contain: 1.2.3.4.5.6.

Methyl Chloride (CH3Cl)Excess and or Unreacted HClWater vapour (a reaction product)Methyl Oxide (0.1 %)Unreacted Methanol (in Trace)Traces of ZnCl2 due to foaming

This hot crude is then condensed in a condenser E101 leading to the gasliquid phase separation inside a knock down drum D101 where:1. HCl and water vapour is condensed as the liquid phase product as31% HCl solution which is pumped back to the process forreutilisation.2. The gas phase products still contains the same material asdescribed above but with lesser amount of HCl which has beencondensed.It is then send for purification process called the Gas Treatment Unit (GTU)where all the impurities, HCl, CH3-O-CH3, trace of ZnCl2 and methanol,water vapour, are removed leaving only a very pure product of methylchloride.Pure methyl chloride is then compressed in a two stage compressor P105the Crepelle compressor, to a Pressure of 9 bar. The temperature of thiscompressed gas is usually 110 C. When this cooled down to below 40 Cin the liquefactor E104, methyl chloride becomes liquid and has a vapourpressure of about 7 bars.Liquified methyl chloride is then stored in the storage tank. It is then filledinto ISO Container (International Standard Organisation) and dispatch toindividual customer.

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Process Flow DiagramFrom the above description, a process flow diagram can be computes asbelow:HClDistillationUnit

GaseousHCl

Reactor

Crude CH3Cl135 C

G100

CondenserE101

MethanolEvaporator

Knock DownDrumD101

VapourMethanol

Liquid CH3Cl35 C7 barPureCH3Cl

LiquefactorE104Liquid CH3Cl35 C7 bar

Remove CH3-O-CH3 &Water Vapour

CH3Cl105 C8 bar

Remove water vapourcompletely

P105

98%H2SO4ColumnC102B

78 %H2SO4ColumnC102A

84 % Full

SodaWashColumnC101

Remove Methanol & ZnCl2& HCl

Brink MistSeparatorR107

Remove HCl Completely

40 C0.3 bar

WaterWashColumnC100

CH3Cl StorageR130

TankerP130

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Methyl ChlorideDetail Description of the reaction Process and Important ControlParametersThe reaction to produce methyl chloride (CH3Cl) is performed byintroducing gaseous HCl ( 96%) and vapour methanol ( 99%) into thebase of a glass-lined reactor G100 which contains a Zinc Chloride solution(acts as the reaction catalyst) at its bottom.

E101Condenser

GaseousProductCrude CH3Cletc

G100D101Knock DownDrum

ZnCl2

HClDistillingColumn

HCl Gas

1m

MethanolVapour

MethanolEvaporator

Liquid Product(31% HCl)

In 25%Excess

Reaction Conditions:Reaction Pressure: 0.5 1 barGReaction Temperature: 145 CCatalyst Concentration: 68 70% (SG 1.96)Catalyst Boiling Point: 150 CHCl Gas Concentration: 96 %Methanol Vapour Concentration: 99 %Excess HCl: 25 %

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The whole reaction process (until final product in storage) takes place in aclosed atmosphere inside the glass lined reactor G100 in the absence of airand other impurities especially oxygen which can form an explosivemixture with methyl chloride. Therefore, it is necessary to purge out allthe air, especially oxygen from all the process equipments using nitrogengas before reaction is carried out.CatalystThe zinc chloride solution inside the reactor has a level of 1 meter in heightmeasures from the injecting point of the raw materials. The bottom part ofthe reactor which contains the zinc chloride solution is called catalystbathofthereactor.Gaseous HCI and methanol vapor will only react inside ZnCl solutioncatalyst bath. Out of the ZnCl solution boundary, reaction will not takeplace. Therefore, a sudden flush of raw material inside the reactor shouldalways be avoided. This is to prevent:a.) Wasteful of raw materials, unreacted HCI and methanolb.) Flooding of the reactorc.) More importantly: Pressure risePressure FactorThe most important factor to note in raw materials feeding is that a suddenflush of methanol and HCI inside the reactor will produce an abundanceyield of methyl chloride gas which gives a sudden pressure rise in thereactor. If this high pressure rise exits the Rupture Pressure Limit of theSafety Rupture Disc on top of the reactor, this disc will blow off leading to acomplete shutdown of the plant for maintenance replacement of a newdisc- In any case, this would be prevented from happening.Side ReactionIt is important to note that, in this process methanol will tend to react in thecatalyst bath with its own molecules to form methyl oxide (CH-0-CH) inthe following way:CHOH + CHOH CH-O-CH + HOMethanol

Methanol

Methyl Oxide

Water

Methyl chloride, being a side reaction product without much usefulness,will not only affects the quality of the main product methyl chloride, butalso will:5

a.) Increase consumption of sulphuric acid which is used to absorb it(methyl oxide) in this gas treatment unit. Thus increase the productioncost.b.) Affects the production rate of the main reaction to yield CHCl in thereactor and thus give a poor production efficiency.c.) Methanol is wasted for its formation of methyl oxide. It is a burden forthe unit production cost of methyl chloride.Fortunately this side reaction can be suppressed to a very small extend (0.1% by weight under normal operation condition) by an excess amount ofHCI feeding into the reactor. The excess HCI (25% extra of require for thereaction) atmosphere will not only increases the frequencies and chancesof the HCI molecules and methanol molecules collision leading to afavorable chemical formation of methyl chloride but also that this excesscan be easily recovered for reutilization in the process.Excess HCIWhen there is an excess HCI atmosphere inside the reactor, the reactionenvironment will change. As soon as the methanol is injected into the zincchloride catalyst bath, its molecules will be surrounded by more HCImolecules, with its aids of the catalysts, favorable reaction for producingCHCl take place. Methyl oxide formation is thus suppressed.But through experience, it is not possible and not practical also to controlthe reaction process in such a way that gives zero production of methyloxide.By experiment and by experience, the most economic way of the operationis by feeing a 25% excess HCI into the reactor. By doing this, methyl oxideformation through the process reaction is only 0.1% under normal optimaloperation condition.This small amount of methyl oxide can be treated in the gas treatment unitby absorption of the sulphuric acid and is get rid of easily.It will be described in later pages about the excess HCI atmosphere in thereactor, and why a 25% excess is required and not more.Therefore, with a 25% excess HCI feeding, the reaction is 99.9% in favor ofmethyl chloride production and 0.1% in favor of methyl oxide formationonly.*This is an important control parameter of the reaction.*

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Catalyst DilutionZnCl

Reaction Formula:

CHOH

+

HCI

CHCl

+

HO

Catalyst

Molecular Weight:

32

36.5

50.5

18

ZnCl2

Reaction Formula:

CHOH

+

CHOH

CH-O-CH + HOCatalyst

Molecular Weight:

32

32

46

18

From the above reaction equation, it is noticed that water, HO, is one ofthe products from the main reaction:18__________Quality of water produced, H0 ==

100%

50.5 + 1826.3% of total product

Actually, this reaction produced water is in vapor state at 145% reactiontemperature. It will come out from the reactor together with the mainproduct CHCl, excess HCI etc. This is then condensed together with themajor part of the excess HCI in Crude Condenser E 101 and is separatedfrom the gaseous products (CHCI etc) in a knock down drum D 101 to givea 31% HCI solution. Therefore, the zinc chloride solution, which has aboiling point of 150c will retain its concentration without being affected bythe water generated through the main reaction.Therefore, as far as the catalyst is concerned, there is no dilution problem,no loss quantity, unless the reactor or the reaction process has beenoperated in a wrong way for a long time. (Foaming of ZnCI inside thereactor will cause only negligible lost of catalyst only.)By wrong operation, this means:a.) Low catalyst temperature during start upb.) Low HCI excess during start upc.) Feed CHOH, methanol first before HCI feeding during start upd.) Low reaction temperatureThe DOGMA of Reaction OperationAs it was mentioned above, that formation of methyl oxide (CH-O-CH)should be avoided or reduced to a minimum extent for economic reason, itis important to observe during any start up operation or increases in7

production rate. Raw material feeding should be carried out in the followingway:Always feeds HCI gas into the Reactor G 100 firstMethanol feeding should follow only if it is 100% sure and confirmedthrough testing at the down stream side of the process that HCI hasalready been introduced into the reactor and is in EXCESS.Therefore, we can say in this way, for this process, the DOGMA of theoperation is Always feeds HCI gas into the reactor first.Control Parameter of the Reaction ProcessIt is mentioned above that, by experience and by experiment, 25% excessHCI feeing is an economic operation process that gives only 0.1% methyloxide formation in the reactor and that this amount of methyl oxide iseasily and quite economically get rid of in the Gas Treatment Unit (GTU)through Sulphuric acid absorption.Operation wise, it is quite impossible to measure the exact flow rate of HCIgas and methanol vapor that is being fed into the reactor, In order to decideand to determine an optimal operation condition, the 31% HCIconcentration in the knock down drum D 101 after a liquid and gas phaseseparation of the reaction products ia an IMPORTANT CONTROLPARAMETER of this process.From the reaction formula:Reaction Formula: CHOHMolecular Weight:32

+

HCI36.5

ZnCl2

CHCl50.5

+

HO18

We know that, if 32 grams if methanol reacts with 36.5 grams of HCI, thereaction will produce 50.5 grams of methyl chloride and 18 grams of water.If HCI is in 25% excess, total HCI gas feed into the reactor will be36.5

______125= 45.625 grams100

Amount in excess is (42.625 36.5) grams or 9.125 grams.This excess will come out from the reactor together with all the gaseousproducts of the reaction, i.e. methyl chloride, water vapor etc.

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At 40c condensation temperature, a major part of the excess HCI willcondense together with almost all the water vapor in a condenser to form31% HCI in the knock down drum D 101.

If the amount of condensate is X,ThenX_______= 0.31X+ 18X = 8.087 gramsThis leaves (9.125 8.087) grams or 1.038 grams of uncondensed HCI to betreated in the gas treatment unit.Under optimal operation condition, a 31% HCI condensate in the knockdown drum D 101 is an indication that the reactor is operated at 25% HCIexcess and that methyl oxide formation is suppressed to a very smallextend of only 0.1%.Therefore: 31% HCI condensate in the knock down drum is an importantcontrol parameter of the whole reaction process.This control parameter is important because it guarantees smoothproduction process and also it is the Base of Trouble Shooting Works ifthings have gone wrong with the process.Trouble Shooting of the Reaction ProcessIn case there is a change in the knock down drum, HCI condensateconcentration (normally 31%), for example a low% HCI condensate and athigh temperature, the methyl chloride crude products condenser E 101must be check of fouling. Its efficiency of condensing should be rectifiedand maintained.The same checking should be carried out on the concentration of the HCIthat is being fed into the HCI distilling column C 201 also.Higher HCI excessFor this process, it is possible, of course, to feed HCI into the reactor G 100at a higher excess rate, but generally, this is not economically favorablebecause of the following reason.

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1. Methyl oxide formation is already very small (0.1% only) at 25% HClexcess will not give very obvious suppression result of methyl oxideformation.2. There will be more uncondensable HCl in the knock down drumwhich willa) increases the work load of the GTUb) requires more waste treatment effort and thus increases theproduction cost3. HCl is wasted.ConclusionFor this reaction process, it is important to note:1. DOGMA : Always feed HCl gas into the reactor first.2. EXCESS: 25% HCl in excess feeding is important.3. CONTROL PARAMETER: 31% HCl in knock down drum is animportant control parameter of the reaction.

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METHYL CHLORIDEProcess Description (an outline)Process Flow DiagramC Valve 203b

Cooling H2OCrude CH3Cl

E101CondenserC Valve 203a32% HClFeed

C201HClDistillationColumn

G100Reactor

E203

HClGas

E204HClReboiler

Azeotropic HCl

D101KnockDownDrumCH3OH Vapour

Liquid Product31% forreutilization

E102MethanolEvaporator

R100Catalyst Tank

Steam CondenserMethanol Feed

Pure CH3Cl

R107BrinkMistSeparator

P105

C100B

C102A

C101

C100

98%H2SO4WashColumn

78%H2SO4WashColumn

CasuticSodaWashColumn

WaterWashColumn

Compressed CH3ClP103B

P103A

P102

CH3Cl StorageR130

P101

Filling (ISO or Cylinders)

E104 Liquefactor

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Process Description (Outline)1.) The Raw Materials Preparation UnitTo produce methyl chloride, the raw materials requires for the reactionarea.) GASEOUS HCI of > 96% concentration andb.) METHANOL VAPOR of > 99% concentration2.) The Reaction UnitBoth the raw materials, i.e Gaseous HCI, methanol vapor are injectedinto the base of a glass-lined reactor G 100 which at its bottom containsliquid Zinc Chloride Solution (70% in concentration) which acts as acatalyst for the following reaction:ZnCl2

+

CHOH

HCI

CHCI + HO

145C

For the same reactor and at the same reaction conditions andconsequences, another side reaction will also take place; ie. theformation of methyl oxide through own molecules reaction of themethanol:CHOH

+

CHOH

ZnCl2

CH-O-CH

+ HO

Fortunately this side reaction can be suppressed to a very small extend(0.1% under normal operation condition) by creating an excess HCIatmosphere inside the reactor. The excess HCI feed is 25% (in extra)After the reaction, the products contain:1) Methyl Chloride(main product of the reaction)2) HCI Gas(Excess upon feeding and or unreacted)3) Water Vapor(a product of the reaction)4) Methanol(Unreacted: in very small quantity)5) Methyl Oxide(Side reaction product : about 0.1%)6) ZnCI(in traces only, due to foaming)This crude products will pass through a condenser E 101 where uponcooling will lead to a liquid-gas phase separation of the product in aknock down drum D 101 wherea) The liquid phase product is a 31% HCI solution which is pumpedback to the process for reutilization

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b)

The gas phase product which contains the same materials as inthe original crude with the most of its water vapor and HCI gascondensed in (a).

The gas phase crude will then send for purification process. The wholepurification facility is called the Gas Treatment Unit3.) Gas Treatment Unit (G.T.U)Gas treatment unit is a very important section of the whole productionprocess, because the quality of the product CHCI totally depends on aproper control of the operation of this whole unit.It mainly consists of four gas wash columns and a brink filter called theBrink Mist Separator.In all the four wash columns, the gas always takes the upward streamflow and the wash solution take a downward flow. They are termly:a) The water wash column C 100 :where all the unreacted methanol trace of ZnCI are completelyremoved and most of the uncondensed HCI are also removed.b) The soda wash column C 101:which acts as a safety precaution Wash Column using 20%caustic solution to remove any trace of HCI not removed by theprevious column.c) The 78% sulphuric acid wash column C 102 A:where all the methyl oxide and most of the water vapor areremoved.d) The strong sulphuric acid (98%) wash column C 102 Bwhere all trace of water vapor are removed.e) The brink mist separator:This only allows dry and pure methyl chloride to pass through.Mist of sulphuric acid is filtered by the Brink candle.4.) Compression, Liquefaction, StorageMethyl Chloride gas up to this state is totally pure and free of anypreviously mentioned impurities except that there might be some inertgases like N, O, in a very small quantity.It is then compressed by a two stages compressor P 105 up to amaximum pressure of < 9 bars (Temperature: 110C after thecompression). This compressed gas is then passed through aliquefactor E 014 where upon cooling, it is liquefied and send intostorage tank R 130 A and R 130 B and store as a liquid product.

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METHYL CHLORIDEDetail Process Description and Unit OperationThe process of methyl chloride production consists mainly the followingfour major sections, namely:1.) Raw Material Preparation Unit includes:a.b.c.

HCI Distillation UnitMethanol EvaporatorCatalyst Preparation Tank

C 201, E 204, E 201, E 202, E 203, R 201 & R 202E 102R 100

2.) Reaction Unit, which include:a.b.c.

ReactorCrude Methyl Chloride Condenser31% HCI knock down drum

G 100E 101D 101

3.) Gas Treatment Unit, which include:a.b.c.d.e.

Water wash columnCaustic wash columnWeak sulphuric acid wash columnStrong sulphuric acid wash columnBrink mist separator

C 100C 101C 102 AC 102 BR 107

4.) Compression and Liquefaction Unit, which include:a.b.

The Crepelle CompressorMethyl chloride liquefactorStorage tank

P 105E 104R 130 A & R 130 B

All these four sections have their unique roll for functions and are equallyimportant in the course of methyl chloride production.A detail description of each section is given below which include:i.) Name of equipmentsii.) Equipment description and functionsiii.) Detail process descriptioniv.)Operation Conditionv.)Operation Procedures ( Individual Unit)

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DETAIL PROCESS DESCRIPTIONRaw Materials Preparation Unita.) HCI Distillation UnitFLOW DIAGRAM: HCI DISTILLATION UNIT95 C

E203RefluxCondenser

34%Feed HClFV211

RefluxCondensate

HCl Distilling ColumnC201

Steam

75 C, 32% HCl

E204Reboiler

CondensateE201HeatExchanger

L

GraphiteJacket

Steam

HCl, 85C

96% HCl

160 C, 5.2 bar

FV221

CoolingWater

130 C

E202AzeoCooler

HV203aTo ReactorG100

HV203bTo HClventabsorptionunit

LV21120% HCl,35C

Azeo HCl, 90C

CoolingWaterR202R201LV201L

20%AzeoHClStorage

32%StrongHClStorage

LV202

L

P201

P202

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HCI DISTILLATION UNITI.) Name of Equipments:No123456789101112131415

CodeC 201E 204E 201E 202E 203R 201P 201R 202P 292HV 203a & HV 203bLV 211LV 201FV 211LV 202FV 221

NameHCI Distilling ColumnHCI ReboilerFeed HCI Heat ExchangerAzeo HCI CoolerReflux CondenserStrong HCI Buffer Storage TankROPAC HCI Feed PumpAzeo HCI Storage TankROPAC Azeo HCI PumpInter-operating ValvesColumn Liquid Level Control ValvesMake up HCI Control ValveFeed HCI Control ValveAzeo HCI Flow Control ValveSteam Flow Control Valve

II.) Equipment Description and Functions1.) C 201: HCI Distilling ColumnDimensionMaterialInternal PackingFacilitated withFunction

Height 7039mm, Outside Diameter 310mmGraphitePacked with 3 layers of PVDF pall ringsBottom liquid level control and recording systemTo generate gaseous HCI of more than 96% concentrationfor process reaction.

2.) E 204: HCI ReboilerDimensionMaterialService FluidFunction

Height 3800mm, Outside Diameter 300mmGraphite, outer surface insulatedSteam for HCI DistillationTo heat up HCI solution for distillation

3.) E 201: Feed HCI Heat ExchangerDimensionMaterialFunction

Height 605mm, Outside Diameter 460mmGraphite, outer surface insulatedUsing heat obtains from the Azeotropic HCI solution topreheat the Stromg Feed HCI Solution (32%) before enteringHCI Distilation Column C 201

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4.) E 202: AZEO HCI CoolerDimensionMaterialFunction

Height 620mm, Outside Diameter 660mmMade of graphiteTo cool down Azeo HCI solution to below 40C beforeentering Azeo HCI solution enter its storage tank R 202

5.) E 203 : HCI Reflux CondenserDimensionMaterialFunction

Height 1499mmMade of graphiteTo condense water vapor coming out from top of HCIdistilling column. Thus, enriches gaseous HCIconcentration.

6. R 201: Strong HCI Buffer Storage Tank (HCI Feed Tank)DimensionMaterialFunction

Height 2800mm, Internal Diameter 1250mmCarbon Steel Tank, internally rubber lined.As 32% HCI Feed tank.

7. P 201: ROPAC HCI Feed PumpPowerMaterialMaximum Del.RateFunction

4kWGraphite Pump35m /hrFeeding strong HCI solution into distilling column

8. R 202: Azeo HCI Storage TankDimensionMaterialFunction

Height 2800mm, Internal Diameter 1250mmCarbon Steel Tank, internally rubber lined.Store Azeo HCI from Distilling Column before sending itfor reabsorption ( reconcentration in HCI plant

9. P 202: ROPAC Azeo HCI Transfer PumpPowerMaterialMaximum del.rateFunction

4kWGraphite Pump37m /hrTo transfer Azeo HCI solution

10. HV 203a & HV 203b: Inter operating Control ValvesService

CONTROL VALVES

HV 203a

Open when reactor G100 is ready to accept > 96% HCIgas for reaction. Remain open when reaction is inprogress. Close when plant trip or shut down.

HV 203b

Open to HCI vent absorption unit during S/U of distillingcolumn or when after plant trip or shut down.

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The above valves HV 203a and HV 203b are inter-operating ie.When HV 203a is opened to feed gaseous HCI (> 96%) into thereactor, HV 203b is cvlosed from sending HCI gas to HCI ventabsorption unit or otherwise: when HV 203a is closed, then at thesame instance HV 203b is opened.11. LV 211: Distilling Column Level control valveServiceFunction

CONTROL VALVESControls and maintains liquid HCI level atbottom of distilling column at 750 mm. This is aLevel Control Valve.

12. LV 201: Make up HCI control valveServiceFunction

CONTROL VALVESTo control make up HCI flow rate so as tomaintain Feed HCI tank R 201 AT HALF. This is alevel control valve.

13. FV 211: Feed HCI Control ValveServiceFunction

CONTROL VALVESTo control HCI flow rate feeding into DistillingColumn. This is a Flow Control Valve.

14. LV 202: Azeo HCI Flow rate Control ValveServiceFunction

CONTROL VALVESTo control Azeo HCI flow rate from Azeo HCIstorage tank R 202 that is being sent forreconcentration process. Also maintains R 202level at half. This is a Level Control Valve.

15. FV.221: Steam Flow Control ValveServiceFunction

CONTROL VALVESTo control steam flow rate into reboiler E 204.This is a Flow Control Valve.

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III.) Detail Process DescriptionHCI Distillation Unit is installed in order to generate gaseous HCI ofmore than 96% concentration for methyl chloride reaction process.In normal operation, the whole unit functions in the following ways:1. Steam is fed onto reboiler E 204 for heating up HCI solution insidethe reboiler.Note: In the case of start up follows a short shut down, steamshould be fed in slowly at first in order to avoid flooding ofdistilling column.2. Pump (P 201) pumps strong HCI (32%) under a well determined ratefrom the strong HCI feed storage tank (R 201) and feedcontinuously into the distilling column C 201.Before entering top of distilling column, strong HCI solution ispreheated by the Azeotropic HCI solution coming out from thebottom of distilling column from 35C to 80C in the heat exchangerE 201.Strong HCI solution enters side way into distilling column top atspace between the column top packing and middle packing.3. On entering the distilling column, liquid HCI will flow downwardsand reaches the bottom of the distilling column and maintains aheight of 750 mm by Level control valve LV 211 situated at thedown stream pipe line of HCI Azeotropic solution. At this state,reboiler is operated under totally immersed condition which hasits best efficiency.4. Inside the Reboiler, HCI solution is heated up to 130C by processsteam and boils and evaporates. When hot HCI solution on top ofreboiler evaporates into the distilling column, azeotropic HCIsolution from bottom of the distilling column comes in to replacethe space: This phenomenon is called Thermosyphoning effect ofthe reboiler.5. Inside the distilling column, HCI being more volatile than water isseparated from its solution and travels up the column. On its path,it comes into contact with the freshly feed HCI from R 201. Usingthe heat it carries, it evaporates HCI gas out from the fresh feed HCIsolution. Thus as this hot gas travels up, its concentration isenriches continuously until when it reaches the top of distillingcolumn, gaseous HCI concentration will be > 96%.

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6. At the same instance that gaseous HCI traveling up the column andenriches its concentration, liquid HCI solution will traveldownwards the column and decreases in HCI concentration. Whenit reaches the bottom of distilling column, its concentration willdecreases from 32% to about 20%. The weak HCI solution is calledthe Azeotropic HCI solution.7. As the distillation process goes on, HCI gas exerts a pressure of1.3 bars in the column.8. Azeotropic HCI solution at the bottom of the Distilling Column willeithera) Acted by the column pressure fo 1.3 bars, flow through HeatExchanger E 201 where it preheats the fresh feed HCI solutionto 80C and is cooled down in Azeo HCI cooler to 40C beforeit enters Azeo HCI storage tank R 202 where pump P 202pumps it away for reconcentration process in HCI plant orsend for vent absorption unit.b) By the thermo-Syphoning effect of reboiler E 204, enters thereboiler proceeding for distillation process.9. During start up period of HCI Distillation Unit, gaseous HCI of lessthan 96% concentration has to be sent to HCI vent absorption unitby way of opening inter-operating valve HV 203b.10. Azeo HCI solution sampling and Test (130C 30% concentration)and Reflux condensate sampling and Test (75C, 32.3% HCI) willprovide information of gaseous HCI coming out from the top of thedstilling column.On top of that, the following control parameter is also important forus to attain an optimal operation condition of distilling column.Reboiler Temperature = 130C (Increases steam flow rate if temperature is below 130C)Distilling Column Top Temperature = 90CReflux Condensate Temperature = 75C

11. An experienced person will need 20 or 30 minutes to bring distillingcolumn under optimal operation condition and provide > 96%gaseous HCI for methyl chloride reaction process.Note: Azeotropic solutionPhysical Chemistry Terms: which mean a solution through boilingand distillation process to separate out one of its component outfrom it, when reaches its Azeotropic Boiling point will give its gasphase product in equivalent concentration to the liquid phasesolution.

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IV Process Operation ConditionsDescriptionService Steam for ReboilerLiquid HCI in ReboilerDistilling Column TopDistilling Column BottomReflux Condenser GasReflux Condenser LiquidFeed HCI from R 201Feed HCI entering C 201Azeo HCI Before E 201Azeo HCI After E 201Azeo HCI Before E 202Azeo HCI After E 202

Temperature160C130C90C130C90C75C< 35C80C130C89C89C< 40C

Pressure5.3 bars1.3 bars1.3 bars-

ConcentrationSteam20%> 96% HCI gas20% Liquid HCI> 96% HCI Gas< 32.3% Liquid Gas32% Liquid Gas32% Liquid Gas20% Liquid HCI20% Liquid HCI20% Liquid HCI20% Liquid HCI

V Operation ProceduresBefore start up HCI Distillation Unit, check and make sure that:a) HCI vent absorption unit in operationb) Inter-operating valves HV 203b is opened and HV 203a is closedc) Pumps P 201 and P 202 are functioningd) Cooling water are on for E 202 and E 203e) Make up HCI is available from General Storage TankVI Operation and Controls1. Feed steam onto the Reboiler E 204Regulates Regulator FIC 221 to control steam flow rate feedingonto the reboiler. Set control valve FV 221 at requires value ofsteam flow rate.Note: In the case of start up after a short shut down of the plant, steamshould be fed in slowly to avoid flooding of distilling column.

2. Start up pump P 201 to feed 32% HCI into HCI Distilling Column 201Regulates Regulator FIC 211 to control HCI flow rate feeding into C201. Set control valves FV 211 at requires value of HCI flow rate.3. Check Level of R 201Regulates Regulator LIC 201 to maintain HCI liquid level in R 201 athalf tank position, This will induce the control on the control valveLV 201 which controls the make up HCI flow rate from the generalstorage.Check and compare HCI flow rate recorded by Flow Recorder FR201 and FR 211:a) FR 201 flow rate = FR 211 flow rate during start up operation of HCI Distilling Column.b) FR 201 flow rate + HCI flow rate from D 101= FR 211 flow rate after reactor G 100 in

21

operation

4. Set level control valve LV 211 to give 750 mm liquid HCI level atbottomof HCI Distilling Column.5. Start up pump P 202 as soon as Azeotropic HCI solution reachesdown to R 202.6. Regulates Regulator LIC 202 to maintain HCI liquid level in R 202 athalf tank position- This will induce control on the control valve LV202 which controls the Azeotropic HCI pumping rate to:a) Azeotropic HCI solution general storage tankb) E 210 in HCI vent absorption unit.7.

Actions to be takenCheck Reflux Condensate Temperature TJR 203Check Reflux Condensate ConcentrationCheck Azeotropic HCI Temperature TJR 201Check Azeotropic ConcentrationCheck gaseous HCI Temperature at Distilling Column Top TJR211

75C32.30%130C20%95C

8. When above conditions are met, interchange operation of valves HV203a and HV 203b.That is:a) Open HV 203a and send > 96% gaseous HCI into reactor G 100reactionb) Close HV 203b to the HCI vent absorption unit.9. Increase steam flow rate and maintains its temperature andpressure whenever HCI Feeding rate into C 201 is increased.10. It takes about 20 or 30 minutes to attain an optimal condition in thedistilling column.Remark: Study P&I of HCI Distillation Unit

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METHYL CHLORIDETHE RAW MATERIALS PREPARATION UNIT0.7 barTo ReactorG100

Pressure induce control valveV4

PV102

3 bar

V3

P

HAP

30% Level

HV122V2

LV102E102

Steam fromBoiler

L

V6 SteamCondensate ByPass ValveFV112R120MethanolStorageTank

MethanolFeedingPump

V5MethanolDrain Valve

7 Pipes

Steam Trap

P120

23

Methanol EvaporatorI. Name of EquipmentsCodeE 102FV 112HV 122PV 102LV 102P 120V1V2V3V4V5V6SPHAPLV 102

II.

Name of EquipmentsMethanol EvaporatorTotal Methanol Flow Control ValveLiquid Methanol Flow Control ValveVapor Methanol Flow Control ValveSteam Flow Control ValveMethanol Feeding PumpEvaporator Feed Methanol Isolation ValveReactor Liquid Methanol Isolation ValveReactor Vapor Methanol Isolation ValveReactor Feed Methanol Isolation ValveEvaporator Methanol Drain ValveEvaporator: Steam by pass valveEvaporator Safety Blow ValveVapor Methanol Pressure GaugeVapor Methanol High Pressure Alarm SystemEvaporator Methanol Levl Indication and Recording SystemSteam Trap

Equipments Description and Its Function1. E 102: Methanol EvaporatorDimensionMaterialFacilities

Length 1.2m, Internal Diameter 0.5m, cylindrical bombshape likeMade of carbon steel. Internally fixed with seven Ushaped steel tubes for steam passing.a.) Level alarm and recording systemb.) Pressure alarm and recording system

Function

a) Service: Tube side: Steam at 160 and 5.2 bars to heatand evaporate methanol into its vapor.b.) Shell side: contains liquid methanol to be evaporatedfor reaction purpose

OtherAccessories

S: Safety Blow ValveP: Vapor Methanol Pressure Gauge

2. FV 112: Total Methanol Flow Rate Control ValveService

Control Valve. Incorporated with Flow Rate Recorder

Function

To control total methanol flow requires for the reactionand recording hourly methanol feeding rate.

24

3. HV 122: Liquid Methanol Flow Control ValveServiceFunction

Control Valve. Hand regulatesTo feed cool liquid methanol into the reactor if reactiontemperature is too high.(Reason: The reaction is exothermic)

4. PV 102: Vapor Methanol Flow Control ValveServiceFunction

Control Valve. This is a pressure induced control valve.Open only when methanol vapor pressure is > 3 barsTo control flow of vapor methanol feeding into the reactor

5. LV 102: Steam Flow Control ValveServiceFunction

Control Valve.To control flow rate of steam in order to provide enoughheat for methanol evaporation.

6. P 120: Methanol Feeding PumpPowerRPMMaximum del. rateMaximum del. pressureFunction

3 kW2900 rpm37m /hr5 barsTo pump liquid methanol from its storage ( R120) and feed into methanol evaporator orreactor.

7. V1: Evaporator Feed Methanol Isolation ValveFunction

To isolate liquid methanol from going into evaporatorwhen methanol evaporator is not in use.

8. V2: Reactor Liquid Methanol Isolation ValveFunction

Isolation valve before HV 122. Open when after E 102 is inoperation and let HV 122 to be regulated for reactiontemperature adjustments.

9. V3: Reactor Vapor Methanol Isolation ValveFunction

Isolate methanol vapor from going into reactor after aplant shut down.

10. V4: Reactor Feed Methanol (Liquid and Vapor) Isolation ValveFunction

Total methanol feed isolation valve.

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11. V5: Evaporator Methanol Drain ValveFunction

To drain evaporator empty after a plant shut down and toavoid a sudden pressure rise in the evaporator when reshut up.

12. V6: Evaporator Steam By Pass ValveFunction

To by pass steam from evaporator steam tube and topurge steam condensate directly after a plant shut down.

13. Steam TrapFunction

To purge steam condensate out from the evaporator whenit is in operation.

III. Detail Process DescriptionMethanol Evaporator E 102 is installed in order to generate vapormethanol and feed this into the reactor to react with gaseous HCI toproduce methyl chloride.When Reactor G 100 is ready to accept vapor methanol for reaction,steam ( at 160C, 5.2 bars steam pressure) is fed into theevaporator E 102. Methanol pump P 120 feeds the evaporatorwith liquid methanol from its storage tank R 120.When liquid methanol level in the evaporator rises and immersesthe steam U-tubes, the heat from the steam will heat up the liquidmethanol and vaporize it. When methanol vapor reaches 3 bars ormore, valve PV 102 is induced to open. Vapor methanol will be fedinto the reactor by the differential of pressure between theevaporator (higher pressure at 3 bars) and reactor ( lower pressureat 1 bar).Methyl chloride reaction is exothermic. ie. heat is generated duringthe reaction, If the reaction temperature is too high, it is necessaryto divert some the liquid methanol and feed them directly into thereactor in order to regulate the reaction temperature. This diversionis achieved through manipulation on the control of valve HV 122.Methanol evaporator will cease its operation when:a) Reactor is operated at very high pressure.b) Evaporator is operated at own high pressure.

26

IV. Process ConditionNo12345678910

DescriptionTotal Methanol Flow RateMethanol Flow Rate for EvaporationVapor Methanol TemperatureVapor Methanol PressureSteam Flow RateSteam PressureSteam TemperatureVapor Methanol High Pressure AlarmVapor Methanol Very High PressureAlarm (Tripping)Level of Methanol Inside Evaporator

Start Up100 kg/hr100 kg/hr110C3 bars30 kg/hr5.2 bars160C

Normal Condition (Max)200 kg/hr100 kg/hr110C3 bars60 kg/hr5.2 bars160C4.5 bars gauge5 bars gauge

half

half

V. Operation ProceduresTo operate methanol evaporator safely and smoothly, it isimportant toobserve the followings:a.) After a plant shut down:1. Always drain evaporator empty of methanol2. Always open steam by pass valve3. Close isolation valves V1, V2, and V3.b.) Before start up evaporator:1. Make sure there is no methanol inside2. Check and make sure that isolation valves V1, V2 and V3 areall at close position as yet.Procedures:1. Feed steam into evaporator slowly.Regulates regulator LIC 102 to pen control valves LV 102Set steam flow rate at 30 kg/hr during S/UCheck steam pressure and temperature at 5.2 bars & 160C2. Close steam by pass valve V6 at steam condensate outlet3. Close methanol drain valve V54. Start up methanol feeding pump P 120Regulates regulator FIC 112 to open control valve FV 112Set FIC 112 to open FV 112 at minimum operating position5. Open isolation valve V1 to feed liquid methanol into EvaporatorE 1026. Wait until the level builds up and immerses the steam tubes.

27

Check level of methanol in evaporator through level recorederLR 102.Set LIC at .Keep close watch on methanol vapor pressure at Localpressure gauge on top of methanol evaporator.7. When methanol vapor pressure is 3 bars or more, open valveV3. At the same time open also valve V2 for stand by.Communicate with control room and informs all the aboveinformation:That is: a.) Methanol vapor pressure is at 3 bars nowb.) Valves V2 and V3 are opened.8. Open valve V4 to feed vapor methanol into Reactor G 100 forreaction with gaseous HCI.Note: As soon as V4 is opened a strong bubbling sound is heardfrom inside the reactor. Reaction is taking place now.The above 2,3,4,5,6,7,8 are on site operation.9. Pass control of methanol evaporator to Control Room.10. Increases reaction rate by regulating FIC 112.Regulates Control Valves FV 112 opening position to increasemethanol flow rate slowly.11. Keep close watch on methanol evaporator pressure and alsoreactor pressure.12. Increases methanol feeding rate in accordance with HCI(Excess) flow rate for the reaction, Keep close watch onCompressor (P 105) performance while reaction rate isincreased.13. When reaction temperature is too high, ie.> 145C,Regulate HIC 122 to open HV 122 to feed in liquid methanol foradjustment on reaction temperature.Note: Total methanol flow rate is not affected.14. Always: proceeds to increase total methanol flow rate intoreactor SLOWLYThis is to avoid a sudden pressure rise in the reactor due to an

28

abundance yield of Methyl Chloride which will cause the rupturedisc on top of Reactor G 100 to blow off leading to a plant shutdown.

29

DETAIL PROCESS DESCRIPTION AND UNIT OPERATIONREACTION UNIT- FLOW DIAGRAM OF REACTION UNIT135C

CH3Cl

135CCoolingWater

E101CondenserRuptureDisc(graphite)2.7 bar

RuptureDisc

High PressureAlarmSystem

35CTrippingPressureAlarmSystem

CrudeCH3Cl

G100ReactorHCl Injectors1.3 bar

HClDistillation Unit

`

CH3OH Injectors1.3 bar

D101KnockDownDrum

145C,ZnCl2

LV101

To R201,31% HCl

Steam

PV102

Catalyst TankR100

P202B

HV122MethanolEvaporator

30

Reaction UnitI.) Name of EquipmentsReaction Unit of Methyl Chloride plant mainly consists of thefollowing equipments:CodeG 100E 101D 101P 202BFR 100PV 101LV 101PAH 101PAHH 101

Name of EquipmentsMethyl Chloride ReactorHot Crude Condenser31% HCI Knock Down Drum31% HCI Solution PumpGaseous HCI Flow Rate RecorderCrude CHCI Pressure Induced Control Valve31% HCI Levl Induced Control ValveReactor High Pressure Alarm CircuitReactor Very High Pressure Alarm and Tripping Circuit

II.) Equipments Description and Functions1. G 100: Methyl Chloride ReactorDimensionMaterial

Description

Function

Outside Diameter 1.4m, Height 5.3mInternally glass lined carbon steel cylindera.) Cylindrical in shape, vertically installedb.) Three HCI injectors and three methanol injectors, enter Reactor at600mm position measures from its base at opposite direction anddirectly pointing at one anotherc.) Bottom of reactor is a Zinc Chloride solution catalyst bath. Its levelis 1m measures from the raw material injection points. This levelcan be check through a level indicator LI 100 installed on the reactor.d.) On top of reactor are(1) Outlet for reaction products(2) A safely rupture disc which leads to catalyst tank if blow off.e.) Temperature Detect Element TE 120 installed on top of reactormeasure gaseous product and indicates by TJR 120 in control roomf.) Temperature detect element TE 120 installed on top of reactormeasure gaseous products temperature and indicates by TJR 120 incontrol roomg.) Near the bottom, there is a man-hole for visual inspection of reactorinternal glass lining or if required enter for spark test.For reaction of gaseous HCI and vapor methanol to take place incatalyst bath inside this reactor

2. E 101: Hot Crude CondenserDimensionMaterialDescription

Function

6.88m in height installed verticallyGraphitea.) This is a graphite heat exchanger. Hot crude enters from top, traveldownwards and come out from bottom. Water enters from side wayat bottom and comes out side way from top.b.) Internally baffledTo condense excess HCI gas from the reactor together with thereaction produced water to form 31% HCI solution

31

3. 31% HCI Knock Down DrumsDimensionMaterial

Description

O.D 1.2M, height 1.4m, bottle shape drumInternally glass lined carbon steela.) Bottom part of this glass lined drum receives 31% HCI solutioncondensed by E 101.b.) Level transmitter LT 101 coordinates with regulator LIC 101 ofcontrol valve LV 101 to maintain drum 31% HCI level at 60% heightof drum.c.) On top is flanged outlet of crude Methyl Chloride and uncondensedvapor and gas and recycles HCI inlet through HCI solution pumpP 202B.

4. P 202B: 31% solution pumpDimensionMaterialMotorNormal Discharge RateMaximum Discharge RateSuction PipeDischarge PipeFunction

O.D 1.2M, height 1.4m, bottle shape drumGraphite pump. ROPAC type2.2kW, 3 phases, 440 volts, 1450 rpm0.15 m/hr2 m/hr50 mm I.D32 mm I.DTo transfer 31% HCI solution receives by D 101 into R201 of HCI Distillation Unit.

5. FR 100: Gaseous HCI Flow Rate RecorderServiceFunction

Gas Flow Rate RecorderTo record hourly gaseous HCI flow rate into Reactor G 100.

6. PV 101: Crude CHCI Pressure Induced Control ValveServiceFunction

Control ValveSet to maintain reactor pressure at 0.5 or 1 bar gauge

7. LV 101: 31% HCI Level Induced Control ValveServiceFunction

Control ValveTo control pumping rate of 31% HCI from D 101 and maintain levelinside D 101 at 60% height.

8. PAH 101: Reactor High Pressure AlarmServiceFunction

AlarmSignal reactor high pressure. Comes out when PR 101 is more than 1.5bars

32

9. PAHH 101: Reactor Very High Pressure Alarm & Tripping CircuitServiceFunction

Alarm & TrippingShut down of plant when reactor is working at very high pressure of >1.75 bars. This will shut off methanol flow control valve FV 112 andsteam valve of evaporator LV 102. Signals reverse operation of HV 203a& HV 203b.

III.) Detail Process Description of Reaction UnitIn normal operation, reaction proceeds in the following ways:1.

Hot Zinc Chloride solution forms a catalyst bath at the bottom ofglass-lined reactor G 100 and immerses HCI gas injectors andmethanol vapor injectors with a level of 1 meter above theseinjectors.

2.

96% above HCI gas feeds into reactor catalyst bath through HCIinjectors. 99% or above methanol vapor feed into reactorcatalyst bath through methanol injectors.Both these raw materials feeds into catalyst bath at oppositedirection pointing directly at one another. As they bubblesthrough the Zinc Chloride solution, with the help of this catalyst,HCI & methanol reacts to form Methyl Chloride thus:HCI

3.

+

CHOH

ZnCl2

CHCI + HO +

Catalyst

h

The reaction products bubbles out from the catalyst solutionand goes into space at reactor top where they find their outletinto that crude Condenser E 101.Note: HCI gas feed was in 25% Excess for the reaction.

4.

As this hot crude enters condensers E 101, it travels downwardsthrough tubes of 10 mm diameter. At the outer surface of thesetubes, cooling water passes at upward direction though bafflesand cools the hot crude down from 135C to 40C.

5.

When this hot crude is being cooled down, the excess fed HCIcondenses together with water vapors produced through thereaction to form a 31% HCI solution.The condensed 31% HCI solution (liquid) is received by knockdown drum D 101.Inside knock down drum D 101, gas phase products and liquidphase products of the reaction are separated with:

6.

33

a. The liquid phase product, ie. 31% HCI solution beingpumped away from the pump P 202B to R 201 for processutilization again.b. The gas phase products which contain:i.) CHCIii.) Uncondensed Water Vaporiii.) Uncondensed HCI gasiv.)Trace of MethanolFind their outlet on top of knock down drum D 101 to the GasTreatment Unit on the process where all impurities are removedfrom Methyl Chloride gas before sending for compression andliquefaction.7.

Until just at the outlet of knock down drum D 101, the reactionunit works on a pressure of 0.5 or 1.0 bar gauge pressure.a. On top of knock down drum D 101, high pressure alarmsystem of reaction unit which include PT 101, PR 101, PSH101, PAH 101 will provide information of reaction pressureand signals alarm of high pressure if this unit works on highpressure.CodePT 101

ComponentsPressure Transmitterinstalled on D 101CHCI outlet line

PR 101

Pressure Recorder

PSH 101

High Pressure Switch

PAH 101

High Pressure Alarm

FunctionsTransmit pressure signal of reactionunit to PR 101 in control roomRecords pressure signals transmitby PT 101 in control roomSignals high pressure alarm PAH 101Alarm comes in when reaction unitpressure is more than 1.5 bars gauge

b. Reactor very high pressure alarm & Tripping Circuit installedbefore (a) which includes1.PSHH 1012.PAHH 101if comes in will:i.) Shut feed steam control valve LV 102 of methanolevaporatorii.) Shut feed methanol control valve FV 112iii.) Inter-operate HV 203a to HV 203b

34

The above will result and bring a shut down of the plant forinvestigation on faults.Under normal operation, PAH 101 setting is 1.5 bars gauge &PAHH setting is 1.75 bars gauge.IV. Operating ConditionsA. TemperatureNo123

DescriptionReaction Temperature (catalyst bath)Product Temperature ( Gas on ReactorTop)31% Condensed HCI at D 101 bottom

RecorderTJR 110

Temperature145C

TJR 120

135C

TJR 101

Below 40C

RecorderPR 101PR 102(ALARM)PAH 101PAHH 101PAH 102PAHH 102

Bars0.5 or 1 bar3 bars(SETTING)1.5 bars1.75 bars4.5 bars5 bars

B. PressureNo123456

DescriptionReaction PressureMethanol vapor (Feed) Pressure(PRESSURE ALARM STSTEM)Reactor High PressureReactor Very High PressureMethanol Evaporator High PressureMethanol Evaporator Very High Pressure

C. LevelNo123

DescriptionReactor Catalyst Level (1m above injector)D 101 31% HCI LevelMethanol Liquid Level in Evaporator

RecorderLI 100LI 101LR 102

Setting1600mm600mm250mm

V. Operation Procedure:Commissioning of the reaction unit brings the whole of MethylChloride plant to its total momentum. Before reaction can actuallystarts in the reactor, the following operation had to be carried outfirst.1. Start-up the cooling water network and make sure sufficientcooling water are supplied to all coolers, condensers,liquefactor,etc.2. HCI vent absorption unit is in operation.3. Gas treatment unit is in operation.4. Steam network is started for HCI Distillation Unit & methanolevaporator.5. Compressor is running with minimum operation suction pressure.

35

6. Reactor had already been filled with minimum operation suctionpressure.7. Reactor had already been filled with Zinc Chloride catalystsolution( > 80C)When all these are ready or in operation, then actual functioning ifthe reaction unit can be achieved through the following operation:1. Inter-operate HV 203a and HV 203b, that is by opening HV 203a tofeed HCI gas into the reactor and close HV 203b from sending HCIgas to HCI vent absorption unit.2. Regulates regulator PIC 101 to keep HCI Distilling Column top at1.3 bars. Check this pressure through HCI Distlling Column TopPressure Recorder PR 211.Note: Wait for few seconds after each regulation of PIC 101 allowresponse from PT 211 to be reflected to PR 211 and showson the recorder.3. Check Gas Treatment Unit water wash column C 100 outlet pH tojustify HCI gas practical for justification.Note: During S/U period, D 101 sampling to test for HCI gaspresence is not practical for justification.Reason: Reaction not yet started, no water produced. E 101couldnt condense pure HCI gas into liquid HCI solution.4. Once C 100 outlet shows presence of HCI gas in the reaction unitsystem, Methanol Evaporator E 102 can be started to introducemethanol vapor into the reactor for the reaction to progress.5. Immediately after reaction started:a) Check reaction pressure, increases compressor P 105suction rate to keep reactor pressure at 0.5 or 1 barb) Increase reaction rate slowly especially the feeding ofmethanol into reactor G 100c) Keep close watch on reaction temperature.6. When reaction is in progress, and if reaction temperature is toohigh, HV 122 can be opened to introduce liquid methanol intoreactor G 100 in order to control the reaction temperature.Opening of HV 122 will not effects the total flow rate of methanol

36

being injected into the reactor as this flow rate is control by FV1112.Note: Regulates steam flow rate into E 102 after opening HV 122liquid methanol feeding valve, in order to keep E 102methanol vapor pressure at 3 bars only. Too high pressurein E 102 may lead to a shut down of plant.7. Performance of compressor must be keep close watch afterreaction unit is in operation. Adjust suction rate of compressor tokeep reactor pressure all times as at (a) of 5.8. When reaction unit is under well control, check D 101 condensedHCI to justify HCI excess of 25%.a) Increase HCI feed to HCI distillation unit if D 101 condensedis below 31%.b) Increased methanol flow rate if D 101 condensate is morethan 31% or else decrease HCI feed to HCI distilling columnif reactor is at its full capacity.9. Starts pump P 202B once methanol is added into the reactor forreaction. Regulates LIC 101 to control pumping rate and tomaintain D 101 level at 600mm all times.

37

GAS TREATMENT UNITI. Name of EquipmentsNo1234567891011

CodeC 100C 102C 102 AC 102 BR 107E 103E 105P 101P 102P 103 AP 103 B

NameWater Wash ColumnCaustic Soda Column78% HSO Column Washing98% HSO Column WashingBrink Mist SeparatorRecycle 78% HSO CoolerRecycle Caustic CoolerC 100 Recycle PumpC 101 Recycle PumpC 102 A Recycle PumpC 102 B Recycle Pump

InstrumentNo123456789101112131415

CodeTJI 130LR 110LAL 110LAH 110TJI 141LR 111LAH 111TJI 152LR 112LAL 112LAH 112LR 122LAH 122PDR 107PDAH 107

NameC 100 Outlet CHCI Gas Temperature IndicatorC 100 Bottom Drum Level RecorderC 100 Bottom Drum Low Level AlarmC 100 Bottom Drum High Level AlarmC 101 Outlet CHCI Gas Temperature IndicatorC 101 Bottom Drum Level RecorderC 101 Bottom Drum High Level AlarmC 102 A Outlet CHCI Gas Temperature IndicatorC 102 A Bottom Drum Level RecorderC 102 A Bottom Drum Low Level AlarmC 102 A Bottom Drum High Level AlarmC 102 B Bottom Drum Level RecorderC 102 B Bottom Drum High Level AlarmR 107 Pressure Drop RecorderR 107 High Pressure Drop Alarm

38

II. Equipments Description and Functions1.) C 100 Water Wash ColumnThis unit consists of:a) An internally glass-lined carbon steel column sectionb) An internally glass-lined bottom drumc) A glass-lined bobbin neck flanged to the column and drum.Column sectionDimension

Bottom SectionBobbin Neck

Outside DiameterHeight of columnOutside DiameterHeight of columnTop FlangeBottom FlangeHeight

300mm4000mm1200mm1500mm300mm500mm620mm

The bottom part of the column section is packed with 35mmPPH pall rings of a length of 2500mm. This is called packedcolumn section.A demister is installed on top of the column. A level transmitteris installed at the bottom drum.Crude Methyl Chloride Gas InletCrude Methyl Chloride Gas OutletRecycle Wash Water InletRecycle Wash Water Outlet(to recycle pump)Function

At the bobbin neckRight on the column top500 mm above the packed columnsectionRight at the bottom

Water is used in this column to absorb methanol vapor,ZnCI and HCI gas carried by the crude methyl chloride gas.

2. C 101: Caustic Wash ColumnThis unit also consists of:a) An internally glass-lined carbon steel column sectionb) An internally glass-lined carbon steel bottom drumc) A glass-lined bobbin neck flanged to the column section andbottom drumThe unit materials, dimension, packing material, crude MethylChloride gas inlet and outlet, recycle wash liquid (NaOH) inletand outlet are all exactly the same as the previous column C100: Water Wash Column. The only exception is a plunging pipesprayer installed on top of the demister use to wash salt crystalforms on the demister. A level transmitter is installed to thebottom drum also.

39

Function

Using 20% caustic soda solution recycling by Pump P102 to absorb any left behind HCI gas from the previouscolumn.

3. C 102 A: 78% HSO Wash ColumnThis unit also consists of:a) An internally glass-lined carbon steel column sectionb) An internally glass-lined carbon steel bottom drumc) A glass-lined bobbin neck flanged to the column section andbottom drumThe unit materials (i.e internally glass lined carbon steel vessel),packing materials dimension of bottom drum and bobbin neck,curde Methyl Chloride gas, recycle wash liquid ( 78% HSO)inlet and outlet are exactly the same two previous wash column.The differences are:1. The column section is shorter, i.e only 3000mm but thepacked column section remains the same as 2500mm.2. No demister is installed on column top (It is not necessaryup to (..) The remaining of the sentence was notprinted on the paper.Function

Using recycle 78% HSO to absorb Methyl Oxide andmost of the water vapor carries by the reaction productMethyl Chloride gas.

4. C 102 B: 98% HSO Wash ColumnMaterial

Carbon Steel VesselColumn section

DimensionBottom Section

Outside DiameterColumn HeightOutside DiameterHeight of column

350mm4500mm600mm1750mm

The packed column section is right in the middle of thecolumn section; the packing material is polypropylene pallrings of 25mm diameter.Methyl Chloride Gas InletMethyl Chloride Gas OutletRecycle Sulphuric Acid InletRecycle Sulphuric Acid Outlet(to recycle pump)

Below the packed column sectionRight on the column topOn top of the packed column sectionRight at the bottom of the acid reservoir

40

Function

Using recycle 98% Sulphuric Acid toabsorb any left behind water vapor fromthe previous column C 102 A.

5. R 107: Brink Mist SeparatorMaterial

Carbon steel cylindrical vesselOutside Diameter500mmDimensionHeight2300mmInternally fix with a Brink Type glass fibre candleGas InletAt 550mm heightGas OutletAbove the candleLiquid InletSame height as gas inletLiquid OutletAt 400mm heightFunction

"Filter" mist of sulphuric acid carries by Methyl Chloridegas. Methyl Chloride gas coming out from this vessel ispure

6. E 103: Recycle 78% HSO CoolerMaterialDimensionCooling AgentLiquid to be cooledTemperature of inlet cooling waterTemperature of outlet cooling waterTemperature of inlet 78% HSOTemperature of after cooled 78% HSOFunction

Tube SideGraphiteShell SideCarbon SteelLength1725mmProcess Cooling Water78% HSO31C32C36.7C35CTo cool down recycle 78%HSO before sending to thecolumn top, C 102 A forabsorption again.

41

7. E 105: Recycle Caustic CoolerThis is a multi-plates cooler.Plate MaterialFrame MaterialNumber of platesDimensionCooling AgentLiquid to be cooledTemperature of inlet cooling waterTemperature of outlet cooling waterTemperature of inlet caustic solutionTemperature of after cooled causticsolutionFunction

TiraneCarbon Steel15 pieces180mm X 585mmProcess Cooling Water20% caustic solution< 31C> 32C> 41.2C< 40CTo cool down recycle causticsolution before sending to C 101column top for absorption columnagain.

8. P 101: C 100 Wash Water Recycle Pump

Pump

MotorFunction

Pump MaterialGraphiteNormal Pumping Rate5m/hrNormal DischargePressure3.7 barsMaximum Head21 metresMotor3 phase / 50HzHorse Power (Hp)3kWRPM1450To recycle wash water from C 100 bottom drum to thecolumn top for the absoprtion process.

9. P 102: C 101 Caustic Recycle Pump

Pump

MotorFunction

Pump MaterialGraphiteNormal Pumping Rate5 m/hrNormal DischargePressure3.7 barsMaximum Head21 metresMotor3 phase / 50HzHorse Power (Hp)3kWRPM1450To recycle caustic solution from C 101 bottom drum tothe column top for the absorption process.

42

10. P 103 A: C 102 A 78% HSO Recycle Pump

Pump

MotorFunction

Pump MaterialHastelloy CNormal Pumping Rate5 m/hrNormal DischargePressure4 barsMaximum Head18 metresMotor3 phase / 50HzHorse Power (Hp)2.2kWRPM1450To recycle 78% HSO from C 102 A bottom drum to thecolumn top for the absorption process.

11. P 103 B: C102 V 98% HSO Recycle Pump

Pump

MotorFunction

Pump MaterialHastelloy CNormal Pumping Rate5 m/hrNormal DischargePressure4 barsMaximum Head18 metresMotor3 phase / 50HzHorse Power (Hp)212kWRPM1450To recycle 98% HSO from C 102 B acid reservoir tothe column top for the absorption process.

12. P 106: 98% HSO Feed Pump

Pump

MotorFunction

Pump MaterialNicromaz CNormal Pumping Rate1 m/hrNormal DischargePressure3.5 barsMaximum HeadMotor3 phase / 50HzHorse Power (Hp)2.2kWRPM2900To feed 98% HSO storage tank into R 107 Brink Mistseparator for C 102 A & C 102 B uses.

43

GAS TREATMENT UNITIII Detail Process DescriptionGas Treatment Unit is an important section in the process of MethylChloride production, as the quality of the final product totallydepends on a proper and careful control of the process conditionsof this section.In this section, there are four chemical reagents wash columns anda mist elimination, namely:CodeC 100C 101C 102AC 102BR 107

ComponentsWater Wash ColumnCaustic Wash Column78% HSO Wash Column98% HSO Wash ColumnBrink Mist Separator

Water is used in the first wash column C 100 to dissolve methanolvapor and trace of ZnCI completely from the crude product. Amajor part of the uncondensed HCI gas is also dissolve by water inthis column.The second wash column C 101, actually acts as a safetyprecaution column. This column uses 20% caustic soda solution todissolves any left behind HCI gas from the first column.In the third column C 102A, 78% HSO removes all Methyl Oxideformed in the side reaction and most of the water from the crudeproduct.The fourth column, 98% HSO Wash Column C 102B, complete thepurification process of the whole unit by removing all the moisturefrom the crude product. Methyl Chloride gas comes from the top ofthis column is dry and traps in the gas stream.Pure Methyl Chloride gas comes out from R 107 is thencompressed, liquefied and stored up.Detail Description of Flow and Process is given below:1.) C 100: Water Wash Column Treatment Process:Crude Methyl Chloride, after its gas-liquid phase separation inKnock Down Drum D 101 enters through gas inlet at the bottomof the packed column section of Water Wash Column C 100.

44

The crude gas travels up to the column top through spacesbetween the pall rings packing while being washed by the waterwashed down from column top. As this crude Methyl Chloridegas comes into contact with the wash water, methanol vaporand trace of ZnCI that it carries is completely dissolved by thewash water. Uncondensed HCI gas from D 101 is also almostcompletely dissolved.Liquid stream wash solution then flows down to the bottomdrum of this wash column forming a 5% HCI solution dissolveswith methanol and trace of ZnCI together with it. This washsolution is then recycled by wash water Recycle Pump P 101and feeds at a rate of 5m/hr to the top of the wash column againfor the same washing purpose.Fresh make-up water feeds constantly (rate = 120kg/hr undernormal operating condition, check flow rate through make-upwater rotameter F1-110) into the wash solution recycle line onthe column top in order to maintain the after washed solution ata constant 5% HCI concentration. This after washed solution isconstantly discharged away to the waste treatment pit where itis treated (neutralized) and disposed off. The rate of discharge isequivalent to the make-up water flow rate feeds into this columnat normal conditions.The discharge line, Tee-out from the Recycle Pump delivery lineis fixed with an automatic level control valve LV 110: Thisenables liquid level in the bottom drum to be controlled at halfall the time. Level control of the bottom drum is importantbecause:1. Recycle Pump P 101 must be assured of constant liquidsupply in order to feed the column with enough washwater and also to avoid this pump from running dry whichmay lead to its damage.2. Crude Methyl Chloride gas must be prevented frombubbling through wash solution in the bottom drum(when level inside is too high) which causes a highpressure drop across this wash column.The Automatic Level Control Valve LV 110 accomplished itsduty of level control in the following way:1. If liquid level in the bottom drum is low, it will closeautomatically and let all wash solution to recycle back tothe column top for washing until liquid level is built upback to half again.

45

2.

If liquid level in the bottom drum is high, it will open moreto increase the discharge rate of 5% HCI solution to thewaste treatment pit until the liquid level is brought downto the set level of half in the bottom drum.

High and Low Level Alarm is installed at the bottom drum tosafeguard smooth running of this washing process.Crude Methyl Chloride gas after water washing, passesthrough a demister at the column top which condenses themoisture the gas carries and enters the second wash columnC 101: Caustic Wash Column for the complete removal of HCIgas from this crude.II C 101: Caustic Wash Column Treatment ProcessComing from the previous column, crude Methyl Chloride gasenters Caustic Wash Column at its gas inlet below the packedcolumn section. The crude gas then travels up to the column topthrough spaces between the pall rings packing of the packedcolumn section.Caustic solution feeds at a rate of 5m/hr by Caustic RecyclePump P 102 enters the column top and flows down. As thiscaustic solution comes into contacts with the crude gas in thepacked column section, any untreated HCI gas from the firstcolumn is immediately (and effectively) absorbed by the causticsolution.Caustic solution then flows down to the bottom drum andrecycles back to the column top for absorption again. As theabsorption reaction of HCI gas by caustic solution generatesheat, caustic solution has to be cooled down first in RecycleCaustic Cooler E 105 before recycling back to the column top.Unlike the washing process in the first column, caustic solutionafter washing crude Methyl Chloride is not continuouslydischarged away. It is because the amount of untreated HCI gasfrom the previous column C 100 is negligible if its processcondition is under well control. The initial concentration ofcaustic solution uses for this column is 20%, it is replaced onlywhen the free 0H content drops to about 2%. Therefore this iscalled a batch-wise process.Methyl Chloride gas again passes through a demister at thecolumn top which condenses its moisture and comes out formthis column completely free of HCI gas. It will then enter the

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third wash column for treatment of Methyl Oxide and watervapor.III C 102 A: 78% HSO Wash ColumnC 102 B: 98% HSO Wash ColumnR 107 : Brink Mist SeparatorThe working process of these equipments: i.e. C 102A, C 102Band R 107 are inter-related. They use sulphuric acid feeds into R107 which then flows to R 102B and R 102A for absorption ofMethyl Oxide and moisture carries by crude Methyl Chloridegas. The after washed sulphuric acid which has a concentrationof 78% is then send to the weak sulphuric acd storage tank. Theafter treatment Methyl Chloride gas which is now pure is sendfor compression, liquefaction process and stores up.Detail Description of the process is given below:a) C 102A: 78% HSO Wash ColumnCrude Methyl Chloride gas enters 78% sulphuric acidWash Column C 102A at the gas inlet below the packedcolumn section. The crude gas travels up through spacesbetween the pall rings packing of this packed columnsection. 78% HSO Recycle Pump P 103A pumps the acidfrom the bottom drum and feed it at a rate of 5 m/hr to thetop of the wash column. This acid flows down to thebottom drum passing through the pall ring packing and asit comes into contact with crude Methyl Chloride gas,Methyl Oxide carries by the gas stream is completelyadsorbed together with most of the water vapor bysulphuric acid.The absorption of water vapor by suphuric acid generatesheat, therefore the recycle acid has to be cooled down inE 103, Recycle HSO before its is fed back to the columntop again.Absorption of Methyl Oxide and water vapor by sulphuricacid in this column attains its best efficiency and is alsoeconomical when the washed down acid concentration is78%. Dilution of the acid by the water vapor it adsorbed isconstantly reconcentrated by make up 98% HSOsupplies from C 102B.In order to maintain level of sulphuric acid in the bottomdrum at half all the time, 78% HSO is constantly sent toits storage tank at a controlled rate. Automatic Level

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Control Valve LV 112 on Pumps P 103A delivery lineperforms the duty of controlling the acid level in thebottom drum. By doing so, Pump P 103A is preventedfrom controlling the acid level in the bottom drum. Bydoing so, Pump P 103A is prevented from running emptyand caused damages. And also methyl chloride can enterthis column smoothly without being forced to bubblethrough the wash liquid and causes high pressure dropacross this column if level of the acid is higher than thegas outlet.The Level Control, Recording, and Alarm system of thiscolumn performs exactly the same as in C 100: WaterWash Column.Crude Methyl Chloride gas comes out from this columncarries along with its small amount of water vapor butcompletely free of methyl oxide, enters the last washcolumn C 102b for complete removal of water vapor bythe 98% HSO in this column.b) C 102B: 98% HSO Wash ColumnMethyl Chloride gas enters the gas inlet below the packedcolumn section of 98% HSO Wash Column C 102B. As inthe previous columns, Methyl Chloride gas travels upbetween spaces of the pall rings packing to the columntop. 98% HSO feeds to the column top at a rate of 5m/hrby Recycle Pump P 103B.As Methyl Chloride gas comes into contact with thewashed down 98% HSO, unabsorbed water vapor fromthe previous column (in small quantity) is completelyabsorbed. Acid then flows down to the bottom acidreservoir and is recycled back to the column top againcontinuously. Fresh supply of 98% HSO flows into theacid reservoir from R 107 Brink Mist Separator outlet lineunder a constant flow rate. Same quantity of 98%sulphuric acid as supplied from R 107 overflowscontinuously through the overflow outlet of the acidreservoir to the bottom drum of C 102A. As there is noacid discharge line on pump P 103B delivery, 98% HSORecycle Pump P 103B is assured of liquid supply.Therefore only high level alarm is installed in order towarn fro proper action to be taken to avoid bubbling ofMethyl Chloride gas through this wash column andcauses a high pressure drop across it.

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Methyl Chloride gas comes out from the column top ofthis last water column is considered to be pure exceptthat some mist of sulphuric acid traps in the gas streamhas to be lastly removed in R 107, Brink Mist Separator.c) R 107: Brink Mist Separator Treatment ProcessMethyl Chloride gas, comes out from C 102B completelydry and free from other impurities enters the gas inlet of R107, Brink Mist Separator together with 98% HSO feedsat a rate of 18kg/hr into CHCI gas line at a Tee- jointbefore the gas entrance to R 107.III Detail Process DescriptionMethyl Chloride gas after passing through Brink Mist SeparatorR 107 is pure and dry. Before its entrance into the MethylChloride Compressor P 105 for compression, its flow rate isdetected (FE 105: Flow Element), measured (FT 105: FlowTransmitter) and recorded (FR 105: Flow Rate Recorder).It then enters a Manifold Receiving pipe (the gas reservoir) ofthe Crepelle Compressor P 105. The compressor will thencompress the pure Methyl Chloride gas from 0.3 bar pressure to2,75 bar at first stage compression. The compressed gas is hotand the temperature is about 110C.This hot Methyl Chloride gas is then cooled down to 40C in thecompressed gas intercooler before it is compressed in thesecond stage.Second Stage Compression gas brings the Methyl Chloride Gasto a pressure of 8 bars (maximum=9 bars). The compressed gasis hot at a temperature of 110C. This high pressure and hotMethyl Chloride gas is then cooled down to below 40C byLiquefactor 104 installed on top of the plant. At 40C, MethylChloride liquefies and becomes liquid which is then flows downby the difference of its static head into Methyl Chloride storagetanks R 130A & R 130B.On top of the storage tank, a chiller unit and a Methyl ChlorideVapor Chiller E 130 is installed. This is to provide a lowtemperature (5C) cooling facilities for the Methyl Chloride vaporfrom the Storage Tank R 130A & B and also those uncondensedvapor from Liquefactor E 104. The vapor after chilled will liquefyagain and flow back to the storage tank.

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At ambient temperature of 35C, pure liquid Methyl Chlorideexerts a vapor pressure of 7 bars in the storage tank. In anycase when this vapor pressure is more than 7 bars, it is anindication that inert gas like N, SO etc is presence in thestorage tank. Through analysis of the gas composition from thestorage tanks by laboratory, vent valve on top of E 130 may beopened to vent off these inert gas in order to bring down thevapor pressure inside the storage tanks back to its normalpressure of 7 bars.IV Compression, Liquefaction and StorageI Name of EquipmentsThis unit deals with the compression, liquefaction and storageof pure chloride. The main equipments are:CodeP 105E 104R 103 A & BP 130E 130PV 105

Name of EquipmentsMethyl Chloride CompressorMethyl Chloride LiquefactorMethyl Chloride Storage TankMethyl Chloride Loading PumpMethyl Chloride Vapor CondenserCompressor P 105 By-Pass Line Control Valve

InstrumentsCodeFR 105PR 105PAL 105TAH 105PR 104PAH 104TJR 103SAL 116

Name of EquipmentsMethyl Chloride Flow Rate RecorderCompressor P 105 Suction Pressure AlarmCompressor P 105 High Suction Pressure AlarmCompressed Methyl Chloride High Temperature AlarmLiquefactor Pressure RecorderLiquefactor High Pressure AlarmLiquified Methyl Chloride Temperature RecorderCompressor Stopped Alarm

II Equipments Description and Functions1.) P 105: Methyl Chloride Compressor (Crepelle Compressor)Nature of CompressorNormal Compression RateMaximum Compression RateRPMNormal Discharge PressureNormal Suction PressureMotor Horse Power (HP)Other Facilities

Two stages compressor312 kg/hr400 kg/hr397 RPM - 875 RPM8 bars, maximum = 9 bars0.3 bar30kW1.) By Pass Gas Cooler2.) Inter-Stage Gas Cooler

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Function

To compress pure Methyl Chloridegas from 0.3 bar to 8 bar

2.) E 104: Methyl Chloride Methyl LiquefactorNatureMaterialDimensionTube SideShell SideFunction

Tube and Shell Type Heat ExchangerCarbon SteelLength 4.5 metres, Outside Diameter (O.D) = 0.4 metresInternal Tubes: 4000mm X 4 pieces24 bafflesTo liquefy compressed Methyl Chloride gas using wateras the cooling agent.

3.) R 130 A and R 103 B: Methyl Chloride Storage TankMaterialDimensionLengthOutside DiameterCapacityFunction

Carbon SteelAs liquid Methyl Chloride storage.

4.) P 130: Methyl Chloride Loading PumpMaterialCapacityNormal DischargePressureRPMMotorHPFunction

Cast Steel (Sealess Pump)10m/hr9.5 bars gauge29003 phase X 440 volts X 50 HzTo load liquid Methyl Chloride from storage tankR 130A & B into ISO container

5.) E 130: Methyl Chloride Vapor CondenserNatureMaterialDimensionTube SideShell SideFunction

Tube and Shell Type Heat ExchangerCarbon SteelLength 4500mm, Outside Diameter (O.D) = 200mm4000mm XXLength36 bafflesUsing chill water from the refrigeration unit to cool downvapor of Methyl Chloride into liquid from storage tanks,ISO container, Liquefactor. And also vent out inert gasfrom the storage and liquefaction system.

6.) PV 105: Compressor P 105 By-Pass Line Control ValveServiceFunction

Control Valve: Pressure InducedAutomatic Control of Suction Pressure of CompressorP 105

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V Operation ProceduresBesides the cooling water network of this plant, Gas treatment Unitis the very first section to put into operation in the process ofMethyl Chloride production. This section is not only important inquality control of the final product; also it is equally important inthe safe running of CompressorP 105, Liquefactor E 104 andstorages R 130 A and R 130 B, all of which depends on a good andpropel control of the process conditions of this section.Followings is a test on operation procedures.1. Check and make sure that cooling water is fed to RecycleCaustic Cooler E 105 ( at 5m/hr) and recycle 78% SulphuricAcid Cooler E 103 ( at 4m/hr)2.

Starts up Wash Water Recycle Pump P 101 of Water WashColumn C 100.Set Regulator LIC 110 to operate Automatic Level ControlValve LV 110 to control the waste water discharge in order tomaintain C 100 bottom drum level at 700mm. Check LevelRecorder LR 110.Feeds make-up water into C 100 column top at 500kg/hr.Check Flow Rotameter FT 110 to assure the make-up waterflow rate.

3.

Starts up Wash Caustic Recycle Pump P 102 of Caustic WashColumn C 101.Check Level Recorder LR 111 of this column to assure ofenough caustic for recirculation by Pump P 102.

4.

Starts up Wash Caustic Recycle Pump P 102 of Caustic WashColumn C 101.Set Regulator LIC 112 to operate Automatic Level ControlValve LV 112 to control 78% HSO discharge rate in order tomaintain bottom drum level of this column ( C 102 A) at700mm. Check Level Recorder LR 112 to make sure of steel.

5.

Starts up 98% HSO Recycle Pump P 103 B of 98% HSOWash Column C 102 B.Check Level Recorder LR 112 of this column to ensure levelof 98% HSO in the reservoir or C 102 B is at its overflowpoint.Note: Pumps P 101, P 102, P 103 A & P 103 B are started upsimultaneously at the same time.

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6.

As soon as reaction started, Feeds R 107 Brink MistSeparator with 98% HSO at 18kg/hr.Check HSO Flow Rotameter FI 107, to ensure of HSO flowrate.

7.

Check PDR 107, Pressure Drop Recorder of Brink MistSeparator R 107. Open R 107 bottom drain valve if LAH 107comes in.

8.

After reaction started,a) Check C 100 waste discharge concentration (HCI) andadjust make up water flow rate accordingly.b) Check C 101 caustic concentration by titration method;replace caustic solution if concentration is below 2%.c) Check temperature of recycle caustic ( TW 151 and TW161) and also temperature of recycle 78% HSO ( TW142 & TW 132)Note: Method of Replacement of Caustic Solution in C 101.a) Open discharge line isolation valve and dischargecaustic solution to waste treatment until level inbottom drum of C 101 is at 10%. Check LR 111.b) Stop discharge to avoid Pump P 102 to run empty.Close discharge isolation valve.c) Feeds Caustic from R 101 to original position ofcaustic level in bottom drum.

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IV Gas Treatment Unit: Normal Operation Conditions of Temperature, Pressure andLevelColumn

Description

TemperatureCHCIgascolumn outlet

C 100

Instrument

ofat

Temperature IndicatorTJI 130

NormalSet Point

40

Actions on Abnormalities1.) If > 40C, check C 100 discharge HCI.Increase make up water flow if necessary.2.) Check HCI excess for reaction. AdjustHCI to C 201 accordingly.3.) Check D 101 HCI concentration, temperatureetc.1.) Check LR 110 of Column C 100 bottom drumlevel. Reset LIC 110 if level too high.2.) Check pressure of other column inlet and otherCompressor P 105 performance.

Pressure of CHCLgas at column inlet

Local Pressure Gauge

0.46 bars

Level of wash waterin bottom drum

Level Indicator LR 110

700mm

Low level alarm ofbottom drum

Alarm LAL 110

450mm

1.) Increase make-up water flow rate: checkdischarge HCI concentration2.) Reset LIC 110 to bring up level to set point

High level alarm ofbottom drum

Alarm LAL 110

950mm

1.) Increase discharge HCI flow rate.2.) Reset LIC 110 to bring down level to set point.

Temperature IndicatorTJI 141

35

1.) Check C 100 performance2.) Check E 105 of foiling, increase cooling waterto E 105 if necessary.

TemperatureCHCIgascolumn outlet

ofat

See Action Below: LAL 110 & LAH 110

1.) Check LR 111 of column C 101 bottomC 101

Pressure of CHCLgas at column inlet

Local Pressure Gauge

0.42 bars

Level of causticsolution in bottomdrum

Level Recorder LR 111

850mm

High level alarm ofbottom drum

Alarm LAH 111

950mm

TemperatureCHCIgascolumn outlet

ofat

Temperature IndicatorTJI 152

drum level. Reset LIC 110.2.) Check pressure of other column and alsocompressor P 105 performance.See Action Below: LAH 1111.) Bring down level of caustic solution inthe bottom drum.

40

1.) If > 40C, check Recycle 78% HSO Cooler E1032.) Increase cooling water flow rate to E 103 ifnecessary.1.) Check bottom drum level, avoid flooding andbubbling of CHCI gas2.) Check pressure of other column and alsoCompressor P 105 performance.

Pressure of CHCIgas at column inlet

Local Pressure Gauge

0.38

Level of 78% HSOin bottom drum

Level Recorder LR 112

700mm

Low level alarm ofbottom drum

Alarm LAL 112

450mm

1.) Reset LIC 112 to bring up level to set point.2.) Check make-up flow rate HSO level in R 107

High level alarm ofbottom drum

LAH 112

950mm

1.) Reset LIC 112. Increase discharge 78% HSOto bring down the level to set point

C 102A

See Action Below: LAL 112 and LAH 112

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Description

Instrument

NormalSet Point

Pressure of CHCIgas at column inlet

Local Pressure Gauge

0.34 bars

1.) Check pressure drop of R 1072.) Check HSO level in R 107

Level of 98% HSOin acid reservoir

Level Recorder LR 122

1250mm

See Action Below on LAH 122

Alarm LAH 122

1500mm

1.) Check over flow line to C 102 A for choke or airlock.2.) Drain to check for sulphate deposit. (Take safetyprecaution)

Pressure RecorderPDR 107

150m HOcolumn

See Action Below

Alarm PDAH 107

500mmHOcolumn

Clean Brink Filter after plant major shut down formaintenance.

Column

C 102B

High level alarm of98% HSO in acidreservoir

R 107

Pressuredropacross brink mistseparatorHigh pressure dropalarm of brink mistseparator

Actions on Abnormalities

IV Compression, Liquefaction and storage: Operation condition, Alarm etc.Equipments

MethylChlorideCompressorP 105

Description

Instruments

Normal SetPoint

Methyl ChlorideCompressor P 105

Flow RateRecorder FR105

150 kg/hrto40 kg/hr

Record accordingly to actual production rate.

Suction Pressureof Compressor

PressureRecorder PR105

0.3 bar

1.) Check production rate.2.) Check compressor performance.3.) Check Compressor By Pass Control Valveperformance.

Compressor LowSuction PressureAlarm

Alarm PAL 105

Check by pass valve operation.

Compressor HighSuction PressureAlarm

Alarm PAL 105

0.5 bar

1.) Check Liquefactor E 104 performance andcompressor discharge pressure.2.) Degass inert if inert content high.3.) Check FR 105 on Methyl Chloride flow rate.4.) Check By Pass Control Valve performance

Compressor HighDischarge GasTemperatureAlarm

Alarm PAL 105

120C

1.) Check intercooler performance, i.e coolingwater temperature

Compressor StopSignal SAL 116

PSL 116 Oil Pressure LowFSL 116 Cooling H0 Flow LowPSLL 116 Suction pressure LowPSHH 116 Discharge Pressure HighTSHH 116 Discharge TemperatureHigh

LiquefactorPressureE 104

- 0.1 bar

Comments and Action on Abnormalities

Liquid MethylChloridetemperature

PressureRecorderPR 104TemperatureRecorderTJR 103

Top up compressor oil before start up again.Rectify cooling water system before start upagainCheck compression and liquefraction unitCheck compressor cooling system

9 bars(maximum)

1.) Check cooling water of E 1042.) Degass inert if inert contact high

40C(maximum)

Check E 104 performance

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HCI Vent Treatment UnitI. Name of EquipmentNo123

CodeE 210C 210P 210

NameHCI Gas Isothermal AbsorberHCI Tail Gas ScubberVent Gas Blower

InstrumentNo1234

CodeTR 400TR 401TAH 401FI 401

NameE 210 Product Temperature RecorderC 210 Scrubbed Water Temperature RecorderC 210 Scrubbed Water High Temperature AlarmC 210 Scrubbing Feed Water Rotameter

II Equipment Description:1. E 210: HCI Gas Isothermal AbsorberMaterialDimension

Function

a.) Absorption Tubes are made of graphiteb.) Cooling water jacket is made of carbon steela.) Absorption tubes: Diameter 24mm, Length 2000mmb.) Cooling water jacket: Diameter 370mm, length: 2000mma.) To absorb HCI gas from HCI Distilling Column 201 (during plantstart up or shut down)b.) To absorb HCI fume from strong HCI Buffer StorageTank R 201 or fume form Azeotropic HCI Receiving Tank R 202

2. C 210: HCI Tail Gas ScrubberMaterialDimensionFunction

PVC, Internally packed with 1500mm, length of PP pall rings of 25mmPVC Pipe: Outside Diameter 150mm, length: 2000mmTo absorb unabsorbed tail gas from E 210

3. P 210: Vent Gas BlowerMaterialFunction

Porcelain Type BlowerTo vent off waste gas from C 210

III Detail Process DescriptionDuring Methyl Chloride plant start up process before HCI DistillingColumn C 201 attains its optimal process condition to give > 96%HCI gas for reactor, Inter-operating Valves HV 203B is opened tosend the early HCI gas from C 201 to the HCI vent Treatment Unit.When plant shut down due to power failure or powe dip, excess HCIgas is also sent to this unit.

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HCI fume from HCI Buffer Storage Tank R 201 and Azeotropic HCIReceiving Tank R 202 is also sent to HCI Vent Treatment Unit forabsorption.The HCI gas (or fume) enters the top of Isothermal Absorber E 210.Weak HCI (20% Azeotropic HCI) send by Pump P 202 enterssideway to the absorber top. These gas and liquid flows down tothe bottom of E 210 through the graphite tubes at the same time forabsorption of gas by weak acid to take place. This acid will thenflow back to R 202 and pump away for further reconcentration inthe HCI plant.Unabsorbed HCI gas is separated at the bottom separator of E 210and flows up to the Tails Gas Scrubber, C 210. This tail gas travelsup through the packed column of C 210 and is absorbed by purewater flows down from the top of the scrubber. The weak scrubbedsolution then flows to the top of E 210 for absorption again. Othergases are vent off to the atmosphere by Vent Gas Blower P 120.HCI Vent Treatment Unit Operation Condition and Alarm:EquipmentsE 210

C 210

Instruments

NormalSet Point

Comments and Action on Abnormalities

E 210 ProductTemperature Record

35C

1. Check cooling water temperature for the absorber2. Check weak acid temperature3. Choke up of absorption tubes4. Absorption liquid not enough (Increase flow rate)

C 210 ScrubbedSolution Temperature

35C

1.) If high temperature: Increase feed water flow rate

Scrubbed Solution HighTemperature Alarm

> 40C

Increase feed water flow rate

Feed Water Rotameter

Adjust flow rate of feed water to C 210 according toproduction rate.

V. Operation Procedures1. Start up Vent Gas Blower P 2102. Feed C 210 with pure waterAdjust water flow rate (Rotameter FI 401) in accordance tothe HCI gas rate from HCI Distilling Column C 201 duringplant start up or shut down.3. Check TR 401 of scrubbed water temperature.Increased scrubbing water flow rate if temperature ofscrubbed water is too high4. Maintain E 210 product concentration at below 34%. Increasescrubbing water feeds into C 210 if E 210 productconcentration is too high.5. Keep observe on level of R 202.

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