Recycling of Waste Plastic

7/21/2019 Recycling of Waste Plastic

1/41i

A final year Project report

On

RECYCLING OF WASTE PLASTIC&PRODUCTION

OF FUEL OIL FROM WASTE PLASTIC

Submitted by

N. Naga Durga (N091052)

P. Mounika (N091725)

Under the guidance of

Mr. M.MADHUSUDHAN REDDY

I n partial ful fi lment of Project work for the award of the degree

Of

BACHELOR OF TECHNOLOGY IN

CHEMICALENGINEERING

RGUKT NUZVID CAMPUS

Rajiv Gandhi University of Knowledge Technologies

Nuzvid, Krishna Dist., Andhra Pradesh


2/41ii

CERTIFICATE

This is to certify that the report entitled as RECYCLING OF WASTE

PLASTIC&PRODUCTION OF FUEL OIL FROM WASTE PLASTIC submitted by N.

Naga Durga (N091052), P. Mounika (N091725),to the department of Chemical Engineering,

RGUKT, Nuzvid, for the award of the degree of Bachelor of Technology in Chemical

Engineering is a bonafide work carried out by them under our personal supervision and

guidance during the academic year 2014-2015. This report is, in our opinion, is worthy of

consideration for the degree of Bachelor of Technology in Chemical Engineering in

accordance with the regulations of the University.

Mr. M. Madhusudhan Reddy, Supervisor,

Head of the Department, Mr. M. Madhusudhan Reddy,

Department of Chemical, Lecturer,

RGUKT Nuzvid, Department of Chemical,

Nuzvid521202 RGUKT Nuzvid,

Nuzvid521202


3/41iii

ACKNOWLEDGEMENT

We would like to express our sincere gratitude toward our guide, Mr. Madhusudhan

Reddy, Lecturer, Department of Chemical Engineering, and for their invaluable guidance and

constant encouragement throughout the course of this project. His unconditional support and

suggestions have proved to be indispensible.

We would like to express our sincere thanks to Mr. M. Madhusudhan Reddy, head of

the department, Department of Chemical Engineering, for giving his support to improve our

knowledge by doing this project using departmental facilities.

Nukella Naga Durga N091052

Palli Mounika N091725

Department of Chemical Engineering

Place: RGUKT Nuzvid

Date: 18/04/2015


4/41iv

ABSTRACT

Plastics are user friendly but not eco-friendly as they are non-biodegradable. A plastic waste

is a municipal solid waste that increases with increasing population. Now a days we are using

plastics in our daily life and it becomes part of our life. We are using plastic as carry bags,

cups and for packaging, and all household items are made up of plastic at present. Disposal of

plastic waste is a menace and become a major problem due to their non-biodegradability and

unaesthetic view. So the best alternative of disposal is to recycle the waste plastic, which will

reduce the effects of plastic pollution thereby protecting our environment.

We have taken the journal Fuel Oil Production from Municipal Plastic Wastes in

Sequential Pyrolysis and Catalytic Reforming Reactors- by Mochamad Syamsiro,harwin

Saptoadi,Tinton Norsujianto, Putri Noviasri, Shuo cheng, Zainal Alimuddin,Kunio

Yoshikawa, as a reference. The aim of this research was to study fuel oil production from

municipal plastic wastes by sequential pyrolysis and catalytic reforming processes. Three

kinds of municipal plastic wastes were collected from the final disposal site. Commercial Y-

zeolite and natural zeolite catalysts were used in this study. The results show that the

feedstock types strongly affect the product yields and the quality of liquid and solid products.

HDPE waste produced the highest liquid fraction. The catalyst presences reduced the liquid

fraction and increased the gaseous fraction. Furthermore, municipal plastic wastes pyrolysis

produced higher heating value solid products than those of biomass and low rank coal.


5/41v

List of figures:

1.1piediagram showing different types of MSW materials

1.2

piechart showing different types of PSW

2.1 Incineration

2.2 Land filling

4.1 Stages of plastic recycling

4.2 process flow sheet of Mechanical recycling

5.1 The feed stock used in the experiments

5.2 X - ray powder diffraction pattern of natural zeolite samples

5.3 Experimental apparatus of liquid fuel production

5.4 Effect of different types of feed stocks

5.5 Effect of catalysts on (a) product yield and (b) liquid fraction composition

List of tables:

4.1 List of different types of plastics and their identification codes

4.2 Calorific values of different types of plastics

5.1 Chemical composition and BET surface area of natural zeolite

5.2 Properties of liquid products for various feed stocks

5.3 Properties of commercial diesel fuels according to Indonesian Government

5.4 Properties of liquid products for different catalysts

5.5 Proximate analysis of solid residues


6/41vi

TABLE OF CONTENTS

TITLE PAGE ..........i

CERTIFICATE....... ii

ACKNOWLEDGEMENT...........iii

ABSTRACT .......iv

LIST OF FIGURES&TABLESv

CHAPTER 1: INTRODUCTION 1

1.1 Types of plastics

1.2 Advantages of plastic

1.3 Disadvantages of plastic

CHAPTER 2: METHODS INVOLVED IN DEGRADATION OF PLASTICS 11

2.1 Incineration

2.2 Land filling

2.3 Need for safe disposal of waste plastic

CHAPTER 3: LITERATURE REVIEW 7

CHAPTER 4: RECYCLING OF WASTE PLASTIC 9

4.1 Need to recycle the plastics

4.2 Stages of plastic recycling process

4.2.1 Plastic identification

4.2.2 Washing the impurities

4.2.3 Tearing of the plastic

4.2.4 Reidentification of plastic grades

4.3

Methods of recycling

4.3.1 Re-extrusion (Primary recycling)

4.3.2 Mechanical recycling (secondary recycling)

4.3.3 Chemical recycling (ternary recycling)

4.3.4 Energy recovery (Quaternary recycling)

CHAPTER 5: FUEL OIL PRODUCTION FROM MUNICIPAL PLASTIC WASTE IN

SEQUENTIAL PYROLYSIS AND CATALYTIC REFORMING REACTORS 19

5.1 Introduction


7/41vii

5.2 Materials and methods

5.3 Results and discussions

5.3.1 Effect of different types of feed stocks

5.3.2 General tests recommended for diesel fuels

5.3.3 Effect of catalysts

5.3.4 Solid residues

CONCLUSION 32

REFERENCES 33


8/411

CHAPTER 1

INTRODUCTION

Plastics have become an indispensable part in todays world. Due to their lightweight,

durability, energy efficiency, coupled with a faster rate of production and design flexibility,

these plastics are employed in entire gamut of industrial and domestic areas. Plastics are

produced from petroleum derivatives and are composed primarily of hydrocarbons but also

contains additives such as antioxidants, colorants and other stabilizers. Disposal of the waste

plastics poses a great hazard to the environment and the effective method has not yet been

implemented. Plastics are slowly biodegradable polymers mostly containing carbon-

hydrogen, and few other elements like nitrogen. Due to its non-biodegradable nature, the

waste plastic contributes significantly to the problem of waste management. According to a

nationwide survey which was conducted in the year 2000, approximately 6000 tons of waste

plastics were generated every day in India, and only 60% of it was recycled, the balance of

40% could not be disposed off. Today about 129 million tons of waste plastics are produced

annually all over the world, out of which 77 million tones are produced from petroleum.

Fig 1.1: pie-diagram showing different types of MSW materials

Plastics are human-made, synthetic polymers made from long chains of carbon and

other elements. Through a process called cracking, crude oil and natural gases are converted

to hydrocarbon monomers like ethylene, propylene, styrene, vinyl chloride, ethylene glycol,

and so on. These are then mixed with other chemicals to produce a desired finished product -

plasticizers like phthalates to make PVC soft, butadiene to make plastic tough, and many

others. Additional additives include bacteria, heat, light, colour, and friction. To create the


9/412

desired form and shape of the plastic, the materials is finally cast, spun, molded, fabricated,

extruded, or applied as a coating on another material [3].

Waste is now a global problem, and one that must be addressed in order to solve the

world's resource and energy challenges. Plastics are made from limited resources such as

petroleum, and huge advances are being made in the development of technologies to recycle

plastic waste among other resources. Mechanical recycling methods to make plastic products

and feedstock recycling methods that use plastic as a raw material in the chemical industry

have been widely adopted, and awareness has also grown recently of the importance of

Thermal recycling as a means of using plastics as an energy source to conserve petroleum

resources.

Fig 1.2: Pie-chart showing diffent types of PSW

It can be said that plastics are synthetic organic materials produced by polymerization. They

are typically of high molecular mass, and may contain other substances besides polymers to

improve performance and/or reduce costs. These polymers can be molded or extruded into

desired shapes.

Plastics are everywhere in our lives - our kitchens, our vehicles, our purses, and even inside

our own bodies. Check out the many ways plastics can be found all around you [3].

High impact polystyrene (HIPS): Vending machine cups, food packaging,

refrigerator liners

High-density polyethylene (HDPE) plastic : Beverage containers, cleaning

product containers, shopping bags, cabling, pipes, wood composites


10/413

Low-density polyethylene (LDPE) plastic s: Produce bags, flexible food

containers, shrink wrap, lining for cardboard, wire coverings, toys

1.1 TYPES OF PLASTICS [6]

Plastic are classified into two types based on their physical properties. They are

1.1.1.Thermoplastics:

Thermo plastic materials are those materials that are made of polymers linked by

intermolecular interactions or van der waals, forming linear or branched structures. These can

be repeatedly soften and melt if enough heat is applied and hardened on cooling, so that they

can be made into new plastic products. Thermo plastics can be heated, moulded and shaped

various ways.

Thermo plastics have wide ranging properties depending upon their chemistry they

can be very much like rubber, or as strong as aluminium. They are light weight with densities

of 0.9 to 2 gm/cc. Some high temperature thermo plastic materials can withstand temperature

of extremes up to 6000F.While others retain their properties at -1000F. Most thermo plastic

materials are excellent insulators both electrical and thermal. On the other hand thermo

plastic composites can be made to be electrically conductive with the addition of carbon or

metal fibres. Most thermo plastics have better fatigue properties than metals and will tolerate

larger deflections than metals without deforming.

Ex: polyethylene, polystyrene and polyvinyl chloride, among others.

1.1.2.Thermosets or thermosetting plastics:

Thermo setting plastics are strong and resistant to heat, but they melt the first time

they are heated to a high enough temperature and harden permanently when cooled. They can

never be melted or reshaped again. During molding, these resins acquire three dimensional

cross linked structure with predominantly strong covalent bonds that retain their strength and

structure even on heating. However on prolonged heating, thermoset plastics get charred. Inthe softened state these resins harden quickly with pressure assisting the curing process.

Thermoset plastics are usually harder, stronger, and more brittle than thermo plastics and

cannot be reclaimed from wastes. These resins are insoluble in almost all inorganic solvents.

They are used in situations where resistance to heat is important. It is used to making

electrical goods.

Ex: phenol formaldehyde and urea formaldehyde.


11/414

1.2 ADVANTAGES OF PLASTICS [5]:

We find considerable growth in use of plastic everywhere due to various beneficial properties

of plastics, such as:

(a) Extreme versatility and ability to be tailored to meet very specific technical needs.

(b) Lighter weight than competing materials, reducing fuel consumption during

transportation.

(c) Extreme durability.

(d) Resistance to chemicals, water and impact.

(e) Better safety and hygiene properties for food packaging.

(f) Excellent thermal and electrical insulation properties.

(g) Relatively inexpensive to produce.

1.3 DISADVANTAGES OF PLASTICS:

(a) Non-biodegradable

(b) They harm the environment by choking the drains

(c) The poisonous gases produces by decompose of plastic cause CANSER

(d) Non-renewable resource

(e) They produce toxic fumes when burnt


12/415

CHAPTER2

METHODS INVOLVED IN DEGRADATION OF PLASTICS

2.1 Incineration:

Incineration means burning of solid waste in controlled conditions. The most usual practice

of disposal of solid waste is burning open fields. This slow burning at low temperature

produces many hazardous gases. This waste contains inorganic matter also. Because of this

burning in heaps there is no control of supply of oxygen or rather there is no oxygen supply

except that present in the voids. This incomplete combustion at a low temperature produces

gases and these gases pollute the environment very close to us. Particularly the gases

produced by the burning of plastic, rubber and other such materials produce very much

harmful gases [1].

Fig 2.1: incineration

2.2. Land Filling:

The most common and easy way of disposal of solid waste is dumping it on the land.When the combined waste (inorganic and organic) is disposed on the land then the

decomposition of the organic matter takes place in due course of time. This

decomposition produces gases (like methane) a dark coloured offensive water known as

leachate. If the ground on which the waste disposed is pervious then this leachate

percolates and mixes with the ground water and badly pollutes it. The mixing of these

pollutants through leachate makes the water polluted and contaminated. Secondly in open

land fills the rain water increases the volume of leachate and mixes it with the ground or

surface water source more easily. So the landfill should be so designed that it contains


13/416

impermeable barrier to stop the mixing of leachate with the water. it should have a

diversion for the rain water and proper arrangement of the collection treatment and

disposal of leachate. Such type of land fill is known as the sanitary landfill. And are the

most desirable ones. They may appear costly, but for long life time of such works and

comparing the end results the cost/ton of waste disposed might be less than any other

method of disposal [1].

Fig 2.2: Land filling

2.3 Need for safe disposal of waste plastic:

Plastic waste should be disposed in a proper manner otherwise it causes many problems. Due

to incineration process toxic release into atmosphere causes environmental pollution and

many health problems. Other way for disposal of waste plastic is land filling, as it takes

thousands of years to degrade they remain in the earth surface causes bio-magnification, land

pollution and decreases and soil fertility. If the plastic filled in the ocean the aquatic life will

disturbed. It forms a thick layer on the water there is no chance for to get oxygen by water

bodies. To avoid all these problems waste plastic should be disposed in safe manner [4].


14/417

CHAPTER 3

LITERATURE REVIEW

3.1 Origin of problem:

Ever since the first industrial scale production of synthetic polymers (plastics) took

place in the 1940s, the production, consumption and waste generation rate of plastic solid

waste (PSW) has increased considerably. Thus, PSW recycling has been a focus of many

researchers in the past few decades. Such research is also driven by changes in regulatory and

environmental issues.

Plastics are used in our daily lives in a number of applications. From greenhouses, coating

and wiring, to packaging, films, covers, bags and containers. It is only reasonable to find a

considerable amount of PSW in the final stream of municipal solid waste (MSW).

Thermoplastics contribute to the total plastic consumption by roughly 80%, and are

used for typical plastics applications such as packaging but also in non-plastics applications

such as textile fibres and coatings (Dewil et al., 2006). While plastics are found in all major

MSW categories, containers and packaging plastics (bags, sacks, and wraps, other packaging,

other containers, and soft drink, milk, and water containers) represent the highest tonnage

(USEPA,2002; USEPA, 2008). In durable goods, plastics are found in appliances, furniture,

casings of lead-acid batteries, and other products. In the UK, recent studies show that PSW

make up 7% of the final waste stream (Parfitt, 2002). Packaging accounts for 37.2% of all

plastics consumed in Europe and 35% worldwide (Clark and Hardy, 2004)[2].

3.2 Prof.Alka U.Zadgoaonkar

a) Prof. Alka U. Zadgoaonkar has invented a process system, which converts polymericmaterials into liquid, solid and gaseous fuel. The process consists of two steps:

b) Random De-polymerization: Loading of waste plastics into the reactor along with the

catalyst system. Random de-polymerization of the waste plastics occurs when plastics are

heated along with catalyst.

c) Fractional distillation: Separation of various liquid fuels by virtue of the difference in their

boiling points.


15/418

The process description:

The waste plastic is sorted based on the physical properties such as hardness, softness, films

etc. Size reduction is carried out using shredder and cutter and graded to uniform size. The

graded feed is mixed and fed to the melting vessel through a pre heater feeder and heated up

to 175-250 0C.The impurities such as clay, metals, glass etc settles at the bottom and sent to

water column for separation of HCL gas and gaseous hydrocarbons. The molten plastic is

sent to main reactor which is maintained at (300-350) 0C and atmospheric pressure, the

reaction takes place in presence of coal and catalyst to convert the molten plastic into

hydrocarbon shall be condensed and separated into liquid and gas streams.

3.3 Jerzy walendziewski and Micczysaw Stciniger:

Jerzy Walendziewski and Micczysaw Stcininger from Wroctaw University of Technology,

Wroctaw, Poland cracked waste samples of polyethylene and polystyrene thermally or in the

presence of catalyst and hydrogen in closed in closed autoclaves. The obtained products were

submitted to analysis; unsaturated hydrocarbons in gasoline and diesel fuel range boiling

were hydrogenated over platinum catalyst. It was stated that the optimum thermal cracking

temperature of waste poly olefines is 410-430 0C, in the case of catalytic process lower

temperature, 390

0

C, cn be used, with reaction time ca, 1.5 an hour. More than 90% yield ofgas and liquid fractions with b.p


16/419

CHAPTER 4

RECYCLING OF WASTE PLASTIC

4.1 Need to recycle the plastics:

Recycling of plastics is desirable because it avoids their accumulation in landfills. While

plastics constitute only about 8 percent by weight or 20 percent by volume of municipal solid

waste, their low density and slowness to decompose makes them a visible pollutant of public

concern. It is evident that the success of recycling is limited by the development of successful

strategies for collection and separation. Recycling of scrap plastics by manufacturers hasbeen highly successful and has proven economical, but recovering discarded plastics from

consumers is more difficult [4].

4.2 Stages of plastic recycling process:

Fig 4.1: stages of plastic recycling

4.2.1 Plastic identification:

Every plastic bag or plastic product can be recycled. Mixed plastic or poor quality plastic or

drawstring bags cant be recycled. Plastic bags and plastic products before taking them into

consideration for a possible recycling [2].


17/4110

Table 4.1: list of different types of plastics and their identification codes

4.2.2Washing the impurities:

Plastic worthy for a recycling, it is separated and taken into the next level, where it is cleaned.

The washing process starts with removing the labels on plastic products, laminated bags or

any other labelled product of plastic. Once the labels are removed the other impurities and

adhesives are removed. Until and unless these impurities are removed the quality of recycled

plastic wouldnt improve[2].

4.2.3Tearing of the plastic:

In the third stage, the waste plastic is loaded onto the conveyor belt that takes the plastic bagsdirectly towards rotating metal teeth that tears the plastic into small pieces. The same plastic

pieces are bagged up and passed through a stringent quality check [2].

4.2.4Re-identification of the plastic grades:

Once the shredded plastic is passed through a stringent quality and chemical test, the plastic

pieces are labelled differently as per the quality of plastics and its grade. Certain Grade

plastics extracted from drawstring bags or plastic products are blended with virgin plastic and

taken to the next level of recycling [2].


18/4111

4.2.5Extruding:

The last stage of the recycling process involves melting the clean plastic pieces and extruding

into the form of pellets. These pallets are then sent to the manufacturing unit, where they are

manufactured with the next lot of plastics. The next lot of plastic is then converted into

wonderful plastic products we use in our daily lives [2].

4.3 Methods of Recycling:

Plastic Solid Waste (PSW) treatment and recycling processes could be allocated to 4 major

categories.

1. Re-extrusion (primary recycling)

2. Mechanical recycling (secondary recycling)

3. Chemical recycling (tertiary recycling)

4. Energy recovery (quaternary recycling)

Each method of unique set of advantages that make it particularly beneficial for specific

locations, applications or requirements. Mechanical recycling (i.e. secondary or material

recycling) involves physical treatment, while chemical recycling treatment produces

feedstock chemicals for the chemical industry. Energy recovery involves complete or partial

oxidation of the material, producing heat, power and gaseous fuels, oil and chars besides by-

products that must be disposed of, such as ash [2].

4.3.1. Re-extrusion (primary recycling):

Primary recycling, better known as re-extrusion, is the re-introduction of scrap,

industrial or single-polymer plastic edges and parts to the extrusion cycle in order to produce

products of the similar material. This process utilizes scrap plastics that have similar features

to the original products. Primary recycling is only feasible with semi-clean scrap, therefore

making it an unpopular choice with recyclers. A valid example of primary recycling is the

injection moulding of out of specification LDPE crates. Crates that do not meet the

specifications are palletized and reintroduced into the recycling loop or the final stages of the

manufacturing. Currently, most of the PSW being recycled is of process scrap from industry

recycled via primary recycling techniques. In the UK, process scrap represents 250,000


19/4112

tonnes of the plastic waste and approximately 95% of it is primary recycled. Primary

recycling can also involve the re-extrusion of post-consumer plastics. Generally, households

are the main source of such waste stream. However, recycling household waste represents a

number of challenges, namely the need of selective and segregated collection. Kerbside

systems are required to collect relatively small quantities of mixed PSW from a large number

of sources. This poses a resource drain and involves significant operating costs in many

countries, especially considering the current market situation.

4.3.2. Mechanical recycling (secondary recycling):

Fig 4.2: Process flow sheet of mechanical recycling

Mechanical recycling, also known as secondary recycling, is the process of recovering plastic

solid waste (PSW) for the re-use in manufacturing plastic products via mechanical means. Itwas promoted and commercialized all over the world back in the 1970s. Mechanical

recycling of PSW can only be performed on single-polymer plastic, e.g. PE, PP, PS, etc. The

more complex and contaminated the waste, the more difficult it is to recycle it mechanically.

Separation, washing and preparation of PSW are all essential to produce high quality, clear,

clean and homogenous end-products. One of the main issues that face mechanical recyclers is

the degradation and heterogeneity of PSW. Since chemical reactions that constitute polymer

formation (i.e. polymer addition, polymerization and poly condensation) are all reversible in

theory, energy or heat supply can cause photo-oxidation and/or mechanical stresses which


20/4113

occur as a consequence. Length or branching of polymer chains can also occur from the

formation of oxidized compounds and/or harsh natural weathering conditions. Due to the

previously stated reasons, it is very important to have a customer ready to purchase the

product to achieve a sensible economical and environmental practice. Nevertheless,

mechanical recycling opens an economic and viable route for PSW recovery, especially for

the case of foams and rigid plastics a number of products found in our daily lives come from

mechanical recycling processes, such as grocery bags, pipes, gutters, window and door

profiles, shutters and blinds, etc. The quality is the main issue when dealing with

mechanically recycled products. The industrial PSW generated in manufacturing, processing,

and distribution of plastic products is well suited for the use as a raw material for mechanical

recycling due to the clear separation of different types of resins, the low level of dirt and

impurities present, and their availability in large quantities. Mechanical recycling of PSW has

also become an important issue in R&D, where numerous researchers have devoted their

efforts to. Recent literature published shows a great interest in utilizing poly olefins that end

up in the PSW stream.

Existing plants and technologies applied in mechanical recycling. PSW via

mechanical means involves a number of treatments and preparation steps to be considered.

Being a costly and an energy intense process, mechanical recyclers try to reduce these stepsand working hours as much as possible. Generally, the first step in mechanical recycling

involves size reduction of the plastic to a more suitable form (pellets, powder or flakes). This

is usually achieved by milling, grinding or shredding the steps involved are usually the

following:

Cutting/shredding:Large plastic parts are cut by shear or saw for further processing

into chopped small flakes.

Contaminant separation: Paper, dust and other forms of impurities are separated

from plastic usually in a cyclone.

Floating:Different types of plastic flakes are separated in a floating tank according to

their density.

Milling: Separate, single-polymer plastics are milled together. This step is usually

taken as a first step with many recyclers around the world.

Washing and drying: This step refers to the pre-washing stage (beginning of the

washing line). The actual plastic washing process occurs afterwards if further

treatment is required.


21/4114

Both washing stages are executed with water. Chemical washing is also employed in

certain cases (mainly for glue removal from plastic), where caustic soda and

surfactants are used.

Agglutination:The product is gathered and collected either to be stored and sold later

on after the addition of pigments and additives, or sent for further processing.

Extrusion:The plastic is extruded to strands and then pelletized to produce a single-

polymer plastic.

Quenching:Involves water-cooling the plastic by water to be granulated and sold as

a final product.

Other single-polymer PSW go through different schemes. Many foams (namely polyurethane,

PU) are powdered and grinded to a particle size less than 0.2 mm using two-roll milling,

cryogenic grinders or precision knife cutters. Another process used in mechanical recycling is

re-bonding, in which recycled foam flakes originating from flexible slab stock foam

production waste are usually blown from storage silos into a mixer that consists of a fixed

drum with rotating blades or agitators, where the foam flakes are sprayed with an adhesive

mixture shows a schematic illustration of the re-bonding process. One of the main advantages

of this process is the ability to obtain a clean product with new properties, i.e. higher density

and lower hardness. In the case of PU, 10% binder is added to the 90% scrap. Waste is

shredded and mixed with binder (dyes can also be added) and the mixture is then compressed.

PU recycled granules are used as filler in polyester moulding compounds and give added

toughness to the material. This process yields a variety of products such as carpet underlay

and athletic mats from recovered pieces of flexible foams. The re-bond process incorporates

both a surprising amount of flexibility and a wide variability in the mechanical properties of

the final product. PVC represents an interesting case too, in terms of mechanical recycling.

Due to its structure and composition, PVC can easily be mechanically recycled in order to

obtain good quality recycling material. Careful and proper sorting is of crucial importance for

the optimal recycling of PVC. After an initial visual check, the collected PVC materials are

shredded into pieces of1015 cm. The metals and non-ferrous metals are mechanically

eliminated afterwards. The company classifies the post-consumer plastics into rigid and

flexible material. Rigid PVC recycled material is mainly used as an inner reinforcement layer

in pipes and profiles production, garden furniture or rigid films manufacture. Flexible PVC

waste is recycled into powder and is used as filler in the production of floor coverings of

various kinds. Other applications are traffic cones, fences, flexible hoses and tubes, footwear,


22/4115

bags, clothing, etc. A valid example of utilizing PSW is the recycling of PET. About three-

quarter of reclaimed PET in the UK and USA is used to manufacture fibres for carpets,

apparel and bottles. Two approaches have been widely promoted, mechanical recycling and

methanolysis (chemical recycling). Once the PET has been collected and sorted, it represents

a feedstock for reclamation processing lines. Reclamation involves washing the materials

(mainly bottles) and conditioning the plastics to be processed as semi-virgin resin or master

batch. In doing so, a clear grade of PET can be produced of high quality to compete with the

virgin polymer. This technique is practiced widely in the EU and USA. In Tokyo (Japan), a

council for PET bottle recycling has been established since 1993 to promote mechanical

recycling of PET bottles in the municipalities of Tokyo. PET bottles obtained by household

sorting are collected, compressed and packed by municipalities for transportation to recycling

plants operated by recycling industries. At the recycling plant, the waste is selected to remove

impurities and the remaining PET bottles are then shredded, cleaned, foreign bodies and non-

resins separated, and the remainder turned into flakes and pellets (granules made of flakes

thermally processed by granulator) for recycling. The recycled materials are then sent to

textile and sheet-making plants, where they are again molten to produce textile and sheet

products by resin moulding techniques well established for PET and other plastics

conversion.

These techniques could be summarized as follows:

Extrusion moulding: The resin or PSW flakes are molten and extruded through a

mould by single or twin screws to form a moulded product. Products from this

process include pipes, sheets, film and wire covering.

Injection moulding: Heated molten resin is injected into a mould to solidify and

form the product desired. Products made this way range from washbowls, buckets and

plastic models to larger products such as bumpers and pallets.

Blow moulding:A parison (hollow plastic melt) obtained by extrusion or injection

moulding is clamped in a mould, and inflated with air to make bottles for all kinds of

uses, such as shampoo bottles. PET bottles are made by means of stretch blow

moulding so as to make them less likely to rupture.

Vacuum moulding:A heat-softened sheet is sandwiched in a mould, and the space

between the sheet and mould sealed and evacuated to form products such as cups and

trays.


23/4116

Inflation moulding: Extrusion moulding where a molten resin is inflated into a

cylinder into form a film. This method is used to make products such as shopping

bags.

Another major company that deals with PSW is Nexcycle Plastics Inc. (NPI, Canada)

which markets a number of recycled products made from scrap polyolefins. NPI deals

with LDPE, LLDPE, MDPE, HDPE and PP. The scrap that is being dealt with is

transformed mechanically to bales, rolls, regrinded PSW, and chunks. The company

also deals with a variety of colored scrap, including clear, white, black, mixed and

printed PSW. Alternatively, many companies deal with black and/or clear scrap for

mechanical recycling processing lines, saving by that cost of sorting. This is the case

of Metals and Recycling Co. (MRC, Kuwait); which covers almost exclusively the

GCC, far and south-eastern Asian markets. The company processes various types of

scrap plastic such as PP, PE, PVC, PPC, ABS, etc. The plants output of PE and PP is

mainly delivered as clean and uniform pellets, whereas other scrap materials are

processed as flakes.

4.3.3. Chemical Recycling (Tertiary Recycling):

Chemical (tertiary) recycling is a term used to refer to advanced technology processes

which convert plastic materials into smaller molecules, usually liquids or gases, which are

suitable for use as a feedstock for the production of new petrochemicals and plastics. The

term chemical is used, due to the fact that an alteration is bound to occur to the chemical

structure of the polymer. Products of chemical recycling have proven to be useful as fuel. The

technology behind its success is the depolymerization processes that can result in a very

profitable and sustainable industrial scheme, providing a high product yield and minimum

waste. Under the category of chemical recycling advanced process (similar to those employed

in the petrochemical industry) appears e.g: pyrolysis, gasification, liquidgas hydrogenation,

viscosity breaking, steam or catalytic cracking and the use of PSW as a reducing agent in

blast furnaces.

Recently, much attention has been paid to chemical recycling (mainly non-catalytic thermal

cracking (thermolysis), catalytic cracking and steam degradation) as a method of producing

various fuel fractions from PSW. By their nature, a number of polymers are advantageous for

such treatment. Polyethylene terephthalate (PET) and certain polyamides can be efficiently

depolymerised. In particular, polyethylene (PE) has been targeted as a potential feedstock for

fuel (gasoline) producing technologies. Studied the thermal cracking behaviour of HDPE. It


24/4117

was reported that PE thermally cracks into gases, liquids, waxes, aromatics and char via five

primary and two secondary reactions to form five lumped products.

There is also a growing interest in developing value added products such as synthetic

lubricants via PE thermal degradation. The development of value added recycling

technologies is highly desirable as it would increase the economic incentive to recycle

polymers. Several methods for chemical recycling are presently in use, such as direct

chemical treatment involving gasification, smelting by blast furnace or coke oven and

degradation by liquefaction. Condensation polymers such as polyethylene terephthalate

(PET) and nylon undergo degradation to produce monomer units, i.e. feedstock or monomer

recycling, while vinyl polymers such as polyolefins produce a mixture containing numerous

components for use as a fuel. Various degradation methods for obtaining petrochemicals are

presently under investigation, and conditions suitable for pyrolysis and gasification are being

researched extensively. Catalytic cracking and reforming facilitate the selective degradation

of waste plastics. The use of solid catalysts such as silica alumina, ZSM-5, zeolites, and

mesoporous materials for these purposes has been reported. These materials effectively

convert poly olefins into liquid fuel, giving lighter fractions as compared to thermal cracking.

The main advantage of chemical recycling is the possibility of treating heterogeneous and

contaminated polymers with limited use of pre-treatment. If a recycler is considering a

recycling scheme with 40% target or more, one should deal with materials that are very

expensive to separate and treat. Thus, chemical recycling becomes a viable solution.

Petrochemical plants are much greater in size (610 times) than plastic manufacturing plants.

It is essential to utilize petrochemical plants in supplementing their usual feedstock by using

PSW derived feedstock.

4.3.4. Energy recovery (quaternary recycling):

By definition, Energy recovery implies burning waste to produce energy in the form of heat,steam and electricity. This is only considered a very sensible way of waste treatment, when

material recovery processes fail due to economical constrains. Plastic materials possess a

very high calorific value (when burned); especially when considering that they are derived

from crude oil. Below table illustrates the calorific value of a number of single-polymer

plastics, compared to oil and MSW. Since the heating value of plastics is high, they make a

convenient energy source. Producing water and carbon-dioxide upon combustion make them

similar to other petroleum based fuels.


25/4118

Table 4.2: Calorific values of different types of plastics


26/4119

CHAPTER 5

Fuel Oil Production from Municipal Plastic Wastes in Sequential

Pyrolysis and Catalytic Reforming Reactors

Catalytic Reforming:

Petroleum refinery process in which low-octane products(such as naphtha) of catalytic

cracking are re-formed into higher-octane ones higher pressure and temperature and in

presence of catalyst.

Chemical recycling via pyrolysis process is one of the promising methods to recycle waste

plastics which involve thermo chemical decomposition of organic and synthetic materials at

elevated temperatures in the absence of oxygen to produce fuels. The process is usually

conducted at temperatures between 500- 8000C. These pyrolytic products can be divided into

liquid fraction, gaseous fraction and solid residues. Pyrolysis or thermal degradation of

plastics has been investigated by many researchers. There are four types of mechanisms of

plastics pyrolysis i.e. end-chain scission or depolymerization, random-chain scission, chain

stripping and cross-linking. Thermal degradation behaviour of plastics has been investigated

by Aboulkas et al. The activation energy and the reaction model of the pyrolysis of

polyethylene (PE) and polypropylene (PP) have been estimated for non-isothermal kinetic

results.

The low thermal conductivity and high viscosity of plastics are the major challenges

for designing the cracking reactor. Several reactor systems have been developed and used

such as batch/semi batch, fixed bed, fluidized bed, spouted bed, microwave and screw kiln.

Batch or semi-batch reactors have been used by many researchers because of its simple

design and easy operation.

Pyrolysis:

Pyrolysis is a process of thermal degradation of a material in the absence of oxygen.

Plastic is continuously treated in a cylindrical chamber and the pyrolytic gases condensed in a

specially-designed condenser system to yield a hydrocarbon distillate comprising straight and

branched chain aliphatics, cyclic aliphatic and aromatic hydrocarbons. The resulting mixture

is essentially equivalent to petroleum distillate. The plastic is pyrolised at 3700C-4200C and

the pyrolysis gases are condensed and liquid separated using fractional distillation to produce

the liquid fuel products [12].


27/4120

Catalytic Cracking:

Petroleum refinery process in which heavy oil passed through metal chambers under high

pressure and high temperature in the presence of catalyst called catalytic cracking.

Thermal degradation:

It means- the breaking down of a chemical compound by heat into smaller

components which do not recombine on cooling. However, the thermal degradation of

plastics has a major drawback such as very broad product range and requirement of high

temperature. Catalytic degradation therefore provides a means to address these problems. The

use of catalyst is expected to reduce the reaction temperature, to promote decomposition

reaction, and to improve the quality of the products. The direct catalytic cracking has been

used widely due to several advantages, mostly in terms of the energy efficiency, with regards

to the use of the reactor, the reaction temperature and the residence time. However, the direct

catalytic cracking of plastic wastes has a number of drawbacks which has prevented its

commercial success. The first relates to difficulty to recover the catalyst after use, which

increases the operational cost. Furthermore, direct contact with plastic wastes will make

catalyst deactivate rapidly due to the deposition of carbonaceous matter and the poisoning

effect of extraneous elements and impurities such as chlorine, sulfur and nitrogen containing

species that may be present in the plastic wastes.

Therefore, separation of catalytic reforming reaction from pyrolysis stage can be applied to

overcome these ZSM-5 catalysts. The results showed an increase in the gas yield and

reduction in the oil yield. The use of other catalysts such as silica alumina and Al-MCM-41

has also been investigated by others. Catalytic reforming of waste agricultural polyethylene

film over Al-MCM-41 catalyst produced heavier hydrocarbon products than HZSM catalyst.

However, the use of catalyst is the main cost burden for recycling of plastic wastes by

pyrolysis. Reducing the catalyst cost for small scale application in developing countries like

Indonesia is very interesting challenges. Natural zeolites which can be found in many places

worldwide including Indonesia might be used as a candidate for this purpose instead of the

commercial catalysts.

A large number of papers have been published describing the pyrolysis of plastics.

There are only few papers utilizing real plastic wastes as feedstocks. Plastic wastes can be

classified as industrial and municipal plastic wastes according to their origins. These groups

have different qualities and properties. Industrial plastic wastes (IPW) are those arising from

the plastics manufacturing and processing industry. Municipal plastic wastes (MPW)


28/4121

normally remain a part of municipal solid wastes as they are discarded and collected as

household wastes. In Yogyakarta city- Indonesia, plastic wastes contributed 9.96% to the

municipal solid wastes.

Pyrolysis and catalytic reforming of MPW which comprise PE, PP and PS have been

studied by Wang and Wang over nickel-loaded silica alumina catalysts. Bhaskar et al. have

compared the thermal degradation products from MPW and model mixed plastics. The

presence of polyethylene terephthalate (PET) in model mixed plastics and MPW increased

the formation of new chlorinated hydrocarbons in liquid products and also drastic decrease in

the formation of inorganic chlorine content. The role of impurities in MPW was also

significant. The impurities were toxic for acidic catalyst and led to easy deactivation of

catalyst in the case of conversion of MPW.

Upgrading of pyrolytic oil produced from MPW has also been investigated using FCC

catalyst as a cracking catalyst. The addition of FCC catalyst in degradation process showed

the improvement of liquid and gas yields and also high fraction of heavy hydrocarbons in oil

product due to more cracking residue. Non-catalytic pyrolysis process has also been studied

using waste PE, PP and PS. The results showed that waste PS produced higher liquid while

waste PE and PP produced higher gaseous products.

In this project, we studied a sequential pyrolysis and catalytic reforming system for

municipal plastic wastes degradation using commercial and Indonesian natural zeolite

catalysts. Our system will utilize all kind of products as fuels including liquid, gaseous and

solid products. This novel proposed system will utilize liquid product for fueling a diesel

engine as a single fuel or blending with commercial diesel fuel. This oil can also be used in a

pressurized cooking stove. The gaseous product can be used either as a heating source for the

reactors or cooking gas stove application. The solid products will be used for co-firing with

coal and biomass which can be utilized as a fuel for several applications.

5.2. Materials and methods:

5.2.1. Materials:

The feedstocks used for these experiments were three kinds of municipal plastic

wastes, i.e. polyethylene bag with (PE bag 2) and without (PE bag 1) crushing and washing,

and high density polyethylene (HDPE) waste after crushing and washing. They were obtained

from the final disposal site and the small plastic recycling company in Yogyakarta city,

Indonesia. The appearance of the feedstocks is shown in Fig. The catalysts used for these

works were commercial Y-zeolite and natural zeolite.


29/4122

The Y zeolite was obtained from Zeolyst International. It has SiO2/Al2O3 mole ratio

of 80, the surface area of 780 m2/g in the powder form. The diameter of the pellet was 1.6

mm which contains 20% of aluminum oxide as a binder. Natural zeolite was collected from

Klaten, Indonesia. The natural zeolite was calcined at 500oC for 3 hours to remove some

volatile substances.

Fig 5.1: The feedstock used in the experiments: (a) PE bag 1; (b) HDPE waste; and (c) PE bag 2.

The chemical properties and BET surface area of natural zeolite is shown in Table 1.

In order to examine the crystalline structure in the natural zeolite, the XRD patterns of sample

is shown in Fig below. It varies depending on their mining sites. It can be seen that the main

structure of the natural zeolite catalyst was identified to be mordenite. Most of the peaks

observed at 2 (degree) = 5-35 for the natural zeolite samples can be assigned to be those of

mordenite type crystalline matter[13] .The samples showed relatively broad base lines. This

suggests that the samples contain amorphous and crystalline impurities.

Mass spectrometry (MS):

Mass spectrometry (MS or mass spec) is a technique used by chemists to determine

molecular structure through ionization and fragmentation of the parent compound into

smaller components. Specific functional groups will fragment in recognizable ways, andchemists can use these patterns to identify functional groups in an unknown compound. MS

can also be used in the food-production industry for detecting small quantities of

contamination such as bacteria in a very reliable way. MS works by ionizing a chemical

compound allowing it to fragment and then measuring the mass to charge ratios of the

resulting ions.

MS can also be combined with a separation technique such as gas chromatography

where a complex mixture of materials is separated and then each compound is analyzed

individually.


30/4123

Gas chromatography (GS):

It is used to separate organic compounds that are volatile. A gas chromatograph

consists of flowing mobile phase, an injection port, a separation column containing the

stationary phase, a detector, and a data recording system.

The organic compounds are separated due to differences in their partitioning behavior

between the mobile gas phase and the stationary phase in the column. Mobile phases are

generally inert gases such as helium, argon or nitrogen [10].

Table 5.1: Chemical composition and BET surface area of natural zeolite (NZ)

Fig 5.2:X-Ray powder diffraction pattern of natural zeolite samples

5.2.2. Pyrolysis and catalytic reforming experiments:

Pyrolysis and catalytic reforming experiments were carried out in a pilot scale two

stage reactor using batch system. It consists of the pyrolysis reactor and the catalytic

reforming reactor. The pyrolysis reactor and the reformer were made of stainless steel and

covered with an electric heater. The pyrolyzers inner diameter and height are 200 mm and

400 mm, respectively. The reformers inner diameter and height are 100 mm and 400 mm,

respectively. A shell and tube type condenser was installed at the outlet of the reformer to

separate gas and liquid products.

In these experiments, 1.6-2.6 kg of the feedstock was fed into the pyrolysis reactor.The pyrolyzer and the reformer were then heated up to the preset temperatures. The catalyst


31/4124

(100 g) was loaded in the catalytic reforming reactor, where the pyrolysis gas generated in the

first reactor was reformed. After having the reforming reaction, the gas was condensed into

liquid products in the condenser. Liquid products were then collected and weighed for mass

balance calculation. The experiments were carried out at the pyrolyzer temperature of 450C

and the reforming temperature of 450C. The gaseous products were burned off to prevent

emission from hydrocarbon gases.

Fig 5.3: experimental apparatus

5.2.3. Liquid product analysis:

The fraction of liquid products were analysed by using a gas chromatography-mass

spectrometry (GC-MS, QP2010S Shimadzu). The column was DB-1 (Crossbond R 100%

dimethyl polysiloxane) capillary column, 30m length with 0.25 mm diameter and 0.2 m film

thickness. Helium was used as the carrier gas. The temperature program used was, initial

temperature 80C for 5 min followed by a heating rate of 8 C /min to 305 C and then held

at 305C for 17 min.

5.3. RESULTS AND DISCUSSIONS:

5.3.1. Effect of different types of feed stocks:

The product yields as the effect of different types of the feedstocks can be seen in Fig 4(a).

Commercial Y-zeolite was used in these experiments. PE bag 1 obtained from the final

disposal site still produced water and highest portion of solid residue because of uncrushed

and unwashed sample. It means that very high impurities were exist in the sample. The water

might be obtained from organic material impurities which normally have high moisture


32/4125

Fig 5.4: Effect of different types of feedstocks on (a) the product yields; and (b) the liquid fraction

composition.

These impurities have also led to a high percentage of gaseous products. The organic

materials such as biomass produced high gaseous fraction up to 50% during pyrolysis

process. All samples produced higher solid residues compared with those of pure plastics as

reported by others which produce less than 5% of residues. It means that the impurities were

dominated in the solid residues. HDPE waste produced highest liquid fraction and lowest

gaseous fraction. The strong structure of HDPE made it more difficult to crack the

hydrocarbon chains into lighter hydrocarbons.

However, the heavy oil fraction was still high in the oil from HDPE waste as shown

in Fig. 4(b) indicating the low quality of the oil. The liquid products have been classified intothree groups i.e. the gasoline fraction (C5-C12), diesel fuel fraction (C13-C20) and heavy oil

(>C20). As can be seen in Fig. 4(b), PE bag 2 produced highest diesel fraction while PE bag

1 produced highest gasoline fraction. As mentioned previously, the organic materials

presence in PE bag 1 contributed to the high fraction of gasoline as reported by Lei et al for

biofuel production. It was found that C6-C14 chemical compounds were up to 95% of bio-

oils. HDPE waste yielded lower diesel fuel fraction than that of PE bag 2. This is due to the

different materials in PE bag 2 which consist mostly of low density polyethylene.

5.3.2. General tests recommended for diesel fuels are:

a) Pour Point

b) Aniline Point-Diesel Index (Cetane Number)

c) Flash Point

d) Calorific Values

e)

Viscosity


33/4126

a) Pour point:

It is the lowest temperature at which the fuel becomes semi solid and loses its flow

characteristics.

Fuel at minimum ambient temperature must be free flowing. In India pour point is fixed at 5

oC.

In Himalaya belt, where climate persists sub-zero level this may not be satisfactory,

hence low pour point oil are essential.

It is also observed that at close approach of pour point (within 2 to 3oC), the viscosity

increases very much, results of which is high pumping cost.

b) Aniline point: Aniline point is defined as the minimum temperature at which equal volume of

anhydrous aniline and oil mix together.

Low aniline point indicates, low diesel index (because of high percentage of

aromatics).

Aniline point can also predict the amount of carbon present in the molecule

(aromatics).

c) Flash point:

It is the minimum temperature at which the vapours from oil sample will give a

momentary flash on application of a standard flame under specific test condition.

In India flash point of diesel kept 5055oC.

d) Calorific value:

It is the energy contained in a fuel, determined by measuring the heat produced by the

complete combustion of a specified quantity of it.

Fuel having calorific value 41.8 KJ per gm is sufficient.

e) Viscosity:

It is a measure of internal resistance offered for the flow of a fluid.

Most important characteristic for storage and use.

For liquids viscosity decreases as temperature increases [12].


34/4127

Table 5.2: Properties of liquid products for various feed stocks

The properties of the liquid products from the pyrolysis and catalytic reforming of

MPW are shown in Table 5.2. The properties of commercial diesel fuels in Indonesia are also

shown in Table 5.3 for comparison. Indonesia produced two kinds of diesel fuels viz. Diesel

48 (Solar) and Diesel 51. As can be seen in Table 5.2 and 5.3, the density of waste plastics

oils (WPO) is acceptable for substituting commercial diesel fuels.

However, the kinematic viscosity of WPO was lower than those of commercial diesel

fuels for PE bag 1 and PE bag 2. The higher fraction of gasoline and the lower fraction of

heavy oil contributed to the lower kinematic viscosity. Viscosity play significant role in the

lubrication of fuel injection systems, particularly those incorporating rotary distributor

injection pumps that rely fully on the fuel for lubrication within the high pressure pumping

mechanism. Lower fuel viscosity lead to greater pump and injector leakage reducing

maximum fuel delivery and ultimately power output. The flash points were lower than those

of diesel fuels. The flash point is an important parameter in relation to fuel storage. Higher

flash point will be safer for storing and transporting the fuels.


35/4128

Table 5.3: Properties of commercial diesel fuels according to Indonesian Government regulation

WPO produced higher pour point than those of diesel fuels since the presence of

heavy oil which normally has high pour point. The property becomes very important when

diesel engine running in very low temperature condition especially in subtropical countries.

The water content presence in WPO was high. It will affect to the performance of diesel

engine.

5.3.3. Effect of catalysts:

Fig. 5.4(a) shows the product yields obtained from the sequential pyrolysis and

catalytic reforming of municipal plastic wastes as the effect of catalysts. PE bag 2 has been

used as a feedstock in these experiments. It can be seen that the thermal pyrolysis (without

catalyst) produced highest liquid fraction. The presence of catalyst reduced the liquid fraction

and increased the gaseous fraction. Theoretically, the catalyst can enhance the cracking

reaction of the pyrolysis gas. Long chain hydrocarbons have been cracked into lighter

hydrocarbon gases. Pyrolysis over natural zeolite catalyst produced higher liquid product

compared with Y zeolite catalyst. This is due to different activity between natural zeolite and

Y zeolite. As can be seen in Table 5.1, NZ has lower BET surface area than that of Y zeolite.

Higher surface area will give more contact between catalyst and pyrolysis gas which means

more gas will be cracked to produce shorter chain hydrocarbons.

However, the presence of catalysts has slightly effect to the product yields. This

might be due to the presence of impurities as mentioned previously. The impurity which

contains some toxic materials will deactivate the catalysts. Thus, the catalysts will have the

activity in the beginning of the reforming process and deactivate in the end of the process.


36/4129

Fig 5.5: Effect of catalysts on (a) the product yields; and (b) the liquid fraction composition.

Fig. 5.4(b) shows the carbon atom number distribution of WPO over different catalysts. The

heavy oil fraction (>C20) could be slightly reduced which affect to the quality of the oils. On

the other hand, the gasoline fractions (C5-C12) were increase because of cracking of longer

chain hydrocarbons into lighter chain hydrocarbons. The diesel fraction was almost similar in

all conditions. This is because the balance between the addition of diesel fraction from heavy

oil cracking and the reduction of diesel fraction cracked into gasoline fraction.

Table 5.4 shows the properties of liquid products over different catalysts. Similar

results have been obtained for all properties. The presence of the catalysts slightly decreased

the pour point. However, the values were still higher than those of commercial diesel fuels.

This condition will make WPO become solid in low temperature condition. The problems

with high pour point of WPO can be overcome by using additional heater before injecting the

fuel to ensure fluidity and keep the viscosity of the fuels. The heating value of WPO was

similar to the common commercial fuels due to the same origin of plastics and commercial

fuels which are produced from petroleum oil.

Table 5.4: Properties of liquid products for different catalysts


37/4130

5.3.4. Solid residues:

The proximate analysis and heating value of the solid residue produced are shown in

Table 5.5. The results show that higher ash content of solid residues produced from MPW

compared with raw plastics as reported in previous works. PE bag 1 produced higher ash

content of solid product than others due to the high impurities which reduce the heating value

of the product. PE bag 2 has lowest ash content and highest heating value. In waste plastics,

fixed carbon and volatile matter contributed to the high heating value of solid products.

Unlike biomass, volatile matters in waste plastics contain mostly hydrocarbon gases which

have high energy content. Therefore, plastic pyrolysis produced higher heating value solid

products than those of biomass and low rank coal as reported by others. Therefore, they can

be used either for blending with biomass and coal or for single fuel [11].

Table 5.5: Proximate analysis of solid residues

CONCLUSION

Sequential pyrolysis and catalytic reforming of Indonesian municipal plastic wastes have

been done over Y- zeolite and natural zeolite catalysts. The results show that the feedstock

types strongly affect the product yields and the quality of liquid and solid products. HDPE

waste produced the highest liquid fraction. However, the heavy oil fraction was still high in

the oil from HDPE waste. The highest diesel fraction has been produced in PE bag 2 while

PE bag 1 produced highest gasoline fraction. The catalyst presences reduced the liquid

fraction and increased the gaseous fraction. Pyrolysis with natural zeolite catalyst produced

higher liquid product compared with Y-zeolite catalyst. However, the presence of catalysts

has slightly effect to the product yields. This might be due to the presence of impurities in

MPW. The quality of WPO was still lower than those of commercial diesel fuels according


38/4131

to the oil properties. Blending of WPO and diesel fuels will obtain better quality of oil. MPW

pyrolysis produced higher heating value solid products than those of biomass and low rank

coal, so that they can be used either for blending with biomass and coal or for single fuel.

Finally we conclude that this recycling process is not only benefits economically but

also give a solution to environmental problems.

FUTURE SCOPE:

Research efforts on the pyrolysis of plastics in different conditions using different

catalysts and the process have been initiated. However, there are many subsequent problems

to be solved in the near future. The present issues are the necessary scale up, minimization of

waste handling costs and production cost, and optimization of gasoline range products for a

wide range of plastic mixtures or waste. Huge amount of plastic wastes produced may be

treated with suitably designed method to produce fossil fuel substitutes. The method is

superior in all respects (ecological and economical) if proper infrastructure and financial

support is provided. So, a suitable process which can convert waste plastic to hydrocarbon

fuel is designed and if implemented then that would be a cheaper partial substitute of the

petroleum without emitting any pollutants. It would also take care of hazardous plastic waste

and reduce the import of crude oil.


39/4132

References:

1. Shailendra Mudgal, Plastic waste in the environment, in association with AEA Energy&

Environment.

2. S.M.Al-salem, P.Lettieri, J.Baeyens, Recycling and recovery routes of plastic solid

waste(PSW), Centre for Co2 Technology, department of chemical engineering, School of

Process Engineering, University college London(UCL), Torrington place, London.

3. An introduction to plastics, Retrieved July 7, 2010, from Calibre Plastics:

http://www.calibre.co.nz/plasticc.htm

4. Life cycle of a plastic product, Retrieved July 8, 2010, from American Chemistry

Council: http://www.americanchemistry.com

5. Partha Das Sharma, keeping world environment safer and greener

6. Converting waste plastic into a resource, Compendium of Technologies.

7. UNEP, Converting waste plastics into resource, Compendium of technologies, United

Nations Environment Programme, Osaka 2009.

8. Dewi NK, challenges from raw materials and exchange rates, Indonesia Updates,

Indonesias plastics industry in 2012, Bank Mandiri.

9. Williams PT Bagri R, Hydrocarbon gases and oils from the recycling of polystyrene

waste by catalytic pyrolysis, International Journal of Energy Research 2004.

10. www.chemicool.com

11. Sheng C, Azevedo JLT, Estimating the higher heating value of biomass fuels from basic

analysis data,Biomass and bio energy 2005.

12. B.K.Bhaskara rao, Modern petroleum refining processes, 5thedition.

13. Trisunaryanti W, Shiba R, Miura M, Nomura M, Nishiyama N, Matsukata M,

Characterization and modification of Indonesian natural zeolites and their properties for

hydrocracking of a paraffin,Sekiyu Gakkaishi 1996.


40/4133

14. Avinash mohapatra, manpreet singh, Preperation of liquid fuels from waste plastic,

Department of chemical engineering, National Institute of Technology, Rourkela.


41/41

Recycling of Waste Plastic

Documents

plastic wasteis

effects of plastic pollution

municipal solid waste

disposal ofplastic waste

waste plasticsubmitted

head ofthe department

nuzvid521202 rgukt nuzvid

journal fuel oil production