Mini Project Edited

PROJECT REPORTON STUDY OF FAMILIARISATION OF PRODUCT (PULVARISER)

Under the guidance of

Aman Seraphim Surin Samuel Devdass( Guide ) ( Guide )

Sr.Engineer, Dy.Manager,Pulv. Engineering, Pulv. Engineering,

BHEL., HYDERABAD BHEL.,HYDERABAD

Submitted by

Ravipati Sita Ram Chowdary (08311A0365)Alupula Joshua (08311A0399)Elluri Karthik (08311A03B9)

DEPARTMENT OFMECHANICAL ENGINEERING

PULVERISERS

FORMS OF COALS

Anthracite

• Contains >92% carbon.• Hard and very brittle, dense, shiny black, and

homogeneous.• The grains break off easily in handling and produce

coarse slack.

Bituminous

• Bituminous coals are soft coals.• When heated, they are reduced to a cohesive,

binding, sticky mass.• They burn easily, especially in pulverized form.• Again 3 types i)Low-volatile bituminous, ii) Medium-

volatile bituminous, iii) High-volatile bituminous.

Subbituminous

• Subbituminous coals are very soft coals.• They are brownish black.• They have high moisture content.

Lignite

• Freshly mined lignite is tough, although not hard, and requires a heavy.

• High moisture and low heating value.• When exposed to air, they lose moisture rapidly and

disintegrates. • Brown coals are readily recovered by strip mining.

History

• In 1890 puverised coal used first time by E.H Hurry and H.Jseaman.

• In U.S.A a man called RAYMOND invented mills to grind coal.

• Were a max. capacity of 6 tons.

CLASSIFICATION OF PULVERISERS

• According to speed i) Low, ii) Medium, iii) High• According to type of principle used i)Impact,

ii) Attrition, iii)Crushing.

Types of Pulverisers

Speed Low(10 to 20 rpm)

Medium(40 to 70 rpm)

High(900 to 1000

rpm)

Mills Ball Tube Mills Ring Roll Mill, Ball &Race

Mill, Bowl Mill

Impact or Hammer Mill, Beater or Fan

Mill

Types of PulverisersParticle reduction principle

Impact Attrition Crushing

Mills Impact mill Ball & race mill,Ball & tube mill

Ball & race mill, Bowl mill

IMPACT MILLS

Ball &Race

Mill

MPS-MILL

Bowl Mill

• Its CE & HP Mill called XRP Mills of INDIA.• XRP is designated as– X- Frequency of power supply.– R- Raymond, the inventor.– P- Pressurised Type.

• HP is designated as– H-High Performance.– P- Pressurised type.

Principle of Operation of Bowl Mill

• Insertion of coal• Running of rollers • Revolution of bowl• Grinding to small particles• Lifting of coal with high pressure & temperature• Collection of pulverised coal at hopper• Collection of iron particles

Bowl Mill

• Major assemblies– Mill Drive and Bowl Assembly– Mill side and Liner Assembly– Separator Body Assembly– Roller Journal Assembly– Mill Discharge Valve Assemblly– Coupling– Tramp Iron Spout Assembly– Pyrite hopperAssembly

Advantages of Bowl Mill

• Low power consumption• Reliability• Minimum maintenance and time required • Wide capacity with good turn down ratio• Ability to handle wide range of coals• Quite and wide range of operations

Bowl Mill• Design improvement– Vane Wheel Assembly to enable Higher Rejects– Modified Venturi Design– Contamination of Gear Case Oil– Wear of Mill Internals– Failure Of Main Vertical Shaft– Oversize Classifier

• Factors affecting Bowl Mill– Size of the Raw Coal– Raw Coal Grindability.

Bowl Mill

• HP & RP Features– Gear Drive – Grinding Elements – Journal Spring Assembly– Journal Assembly– Tall Top Classifier– Scrapper Assembly

Bowl Mill• Operating Parameters– Mill Airflow– Mill Outlet Temperatures– Pulverised Fuel Fineness– Bowl DP

• Problems faced– Fineness of Coal – inconsistency– Classifier outlet temperature low– Fire and explosion in Mill circuit– Mill Rejects

• Life Improvement of wear parts

Bowl MillTrouble Shooting•Abnormal noise in mil base •Abnormal noise in mill side •Abnormal noise in separator body•Oil leakage from worm shaft packing gland•High pulverised fuel fineness•Scraper failure•Prematuer coupling failure•Oil filters choking•Malfunctioning of NRV•Frequent mechanical seal failure

Ball Tube Mill

• It is designated as BBDxxxx– B – Boyars (body)– B – Boullets (balls)– D – direct (direct firing)– xx – diameter of the mill (in decimeters)– xx – length of the mill (in decimeters)

Ball Tube Mill

Ball Tube Mill

• Mechanical description– BODY– BALL FILLING SYSTEM– TRUNNION– BEARINGS– THE SEALING SYSTEM– DRIVE UNIT– TURN GEAR– CLASSIFIER– MIXING BOX– PF SHUT OFF GATE– SOUND HOOD– FIRE PROTECTION

Ball Tube Mill

• Factors Affecting Ball Tube Mill– Flow of pulveriser coal– Moisture content of coal– Hardgrone grindability index– Coal fineness at in the mill– Inside diameter of the mill– Rotational speed of mill