Waste plastics to fuel pdf

Pyrolysis is a recycling technique converting plastic waste into fuels, monomers, or other valuable materials by thermal and catalytic cracking processes. It allows the treatment of mixed, unwashed plastic wastes.

For many years research has been carried out on thermally converting waste plastics into useful hydrocarbons liquids such as crude oil and diesel fuel. Modification made by Aspen Hysys program for thermofuel process to improve the efficiency of the process.

This paper reviewed the thermal and catalytic degradation of plastics through pyrolysis process and the key factors that affected the final end product, for instance, oil, gaseous and char.

Additionally, the liquid fuel properties and a discussion on several perspectives regarding the optimization of the liquid oil yield for every plastic were also included in this paper. The use of pyrolysis as a waste disposal method for waste plastics has been well established. However, the market value of the recycled plastic products and separate upgrading of the pyrolysis product liquid are some of the challenges facing the process.

The obtained results show that the adding of a plastic mix improves the overall efficiency of the slow pyrolysis of pine. Therefore, it was possible to achieve higher liquid yields and less solid product than in processes are distillation, cracking and pyrolysis.

The pyrolysis liquid products of waste lubricant oil can be used as alternative engine fuel. Conversion Methods Mohan et. Waste plastic pyrolysis plant is a kind of machine that can dispose of waste plastic into fuel oil. The amount of plastic waste is growing every year and with that comes an environmental concern regarding this problem. Pyrolysis as a tertiary recycling process is presented as a solution. Pyrolysis can be thermal or catalytical and can be performed under different experimental conditions.

These Plastic pyrolysis plant converts plastic waste to liquid fuel. The systems use a continuous liquefaction technology alongside a unique catalytic breakdown process that turns waste materials into gases and liquids. Since plastics were part of petroleum, the oil produced through the pyrolysis process was said to have high calorific value that could be used as an alternative fuel.

This paper reviewed the This research describe a comparison of the use of pyrolysis oils which are the tire pyrolysis oil, plastic pyrolysis oil and diesel oil in the assessment of engine performance, and feasibility analysis.

Pyrolysis oils from waste tire and waste plastic are studied to apply with one cylinder multipurpose agriculture diesel engine. It is found that without engine modification, the tire pyrolysis Abstract. The present work involves the study of process optimization for the production of liquid fuel by the catalytic pyrolysis of different plastics waste such as polypropylene, low density polyethylene and polystyrene using kaolin and acid treated kaolin as catalyst in a A Patent Review on Pyrolysis of Waste Plastic and Scrap Tire into Liquid Fuel and Useful Chemicals By Ben Bahavar, Ph.

This article provides an … In pyrolysis plastic to oil process, the plastic waste is not burned. Plastic to oil is environment friendly technology for disposal of plastic waste. For the pyrolysis of refuse plastic fuel RPF , the typical particle size is large and the time required for pyrolysis is long. Different type of catalysts, natural and synthetic, can be used for conversion of organic wastes into valuable fuels.

The aim of this work is conversion of waste polyolefin mixture and production of liquid fuel Based on the studies on literatures, pyrolysis process was chosen by most researchers because of its potential to convert the most energy from plastic waste to valuable liquid oil, gaseous and char. Therefore, it is the best alternative for plastic waste conversion and also economical in terms of operation. The flexibility that it provides in terms of product preference could be achieved by completion of the pyrolysis process was 90 minutes without catalyst and 65 minutes with natural zeolite.

Results showed Results showed that in absence of catalyst, process gives about WtE is a form of energy recovery. Most WtE processes produce energy directly through combustion, or produce a combustible fuel commodity, such as methane, methanol, ethanol or synthetic fuels. Williams, Fuel, Oct. This liquid can be separated into light and higher fractions. Thus, the derived oils may be used directly as fuels, petroleum refinery feedstock.

Altayeb A Thesis Presented to the Faculty of the 4-Catalytic pyrolysis of waste plastic into liquid fuel. Search Search to produce liquid fuel similar to diesel from plastic waste. The pyrolysis process for plastic takes the long chain polymer molecules and breaks or cracks them into shorter chains through heat and pressure. In fact, the plastic to fuel conversion process can be also called plastic pyrolysis process. This process results in the conversion of these components into hydrocarbon monomers such as ethylene and propylene.

Further processing leads to a wider range of monomers such as styrene, vinyl chloride, ethylene glycol, terephthalic acid and many others. These monomers are then chemically bonded into chains called polymers. The different combinations of monomers yield plastics with a wide range of properties and characteristics.

Many common plastics are made from hydrocarbon monomers. These plastics are made by linking many monomers together into long chains with a carbon backbone. Polyethylene, polypropylene and polystyrene are the most common examples. Even though the basic makeup of many plastics is carbon and hydrogen, other elements can also be involved.

Oxygen, chlorine, fluorine and nitrogen are also found in the molecular makeup of many plastics. Polyvinyl chloride PVC contains chlorine. Nylon contains nitrogen.

Teflon contains fluorine, Polyester and polycarbonates contain oxygen. These polymers can be molded or extruded into desired shapes. There are two main types of plastics: thermoplastics and thermosetting polymers. Examples are polyethylene, polystyrene and polyvinyl chloride among others. They are not suitable for repeated heat treatments; therefore after they have solidified, they stay solid. Examples are phenol formaldehyde and urea formaldehyde.

The conversion methods of waste plastics into fuel depend on the types of plastics selected and the properties of other wastes that might be used in the process. Additionally the effective conversion requires appropriate technology to be selected according to local economic, environmental, social and technical constraints.

In general, the conversion of waste plastic into fuel requires feedstock which are non-hazardous and combustible. Each type of waste plastic conversion method has its own suitable feedstock. The composition of the plastics used as feedstock may be very different and some plastic articles might contain undesirable substances e.

The types of plastics and their composition will condition the conversion process and will determine the pretreatment requirements, the combustion temperature for the conversion and therefore the energy consumption required, the fuel quality output, the flue gas composition e.

Depending on their structures e. Although wooden materials are formed into pellets using a pelletizer, mixing plastics with wood or paper complicates the pellet preparation process. Suitable heating is required to produce pellets from thermoplastics and other combustible waste.

In liquid fuel production, thermoplastics containing liquid hydrocarbon can be used as feedstock. The type of plastic being used determines the processing rate as well as the product yield. Contamination by undesirable substances and the presence of moisture increases energy consumption and promotes the formation of byproducts in the fuel production process.

When using fuel prepared from waste plastics, it must be assured that the flue gas composition complies with local air pollution regulations. In the same way, ash quality must also be in compliance with local regulations when disposed at the landfill. If there aren't any relevant regulations, both the producers and consumers of the recycled fuel should control the fuel quality and the emissions at combustion in order to minimize their environmental impact.

Table 2. It can be observed that thermoplastics consisting of carbon and hydrogen are the most important feedstock for fuel production either in solid or liquid form. As shown in Table 2. The addition of thermosetting plastics, wood, and paper to the feedstock leads to the formation of carbonous substances and lowers the rate and yield of Squid products. Fuel from this type of plastic is a source of hazardous components Nitrogen : Polyamide, Polymer containing such as NOx or SOx in polyurethane.

Flue gas Sulfur: Polyphenylene sulfide. Polypropylene, Allowed. Liquid hydrocarbons Polystyrene, Allowed. Polymethyl metacrylate. Acrylonitrile Butadiene Allowed. But not styrene Copolymer ABS suitable. Nitrogen- Liquid containing fuel is Hydrocarbons obtained. Special attention required to cyanide in oil. Polyvinyl alcohol PVA Not suitable.

Formation of water No hydrocarbon and alcohol. Polyoxy methylene POM suitable for fuel. Not suitable. Formation of formaldehde. Polyethylene Terephthalate Not suitable.

Polyurethane PUR Not suitable. Only certain types of thermoplastics undergo thermal decomposition to yield liquid hydrocarbons. Depending on the components of the waste plastic being used as feedstock, the resulting liquid fuel may contain other contaminants such as amines, alcohols, waxy hydrocarbons and some inorganic substances.

Contamination by nitrogen, sulfur and halogens gives flue gas pollution. Unexpected contamination and high water contents may lower the product yields and shorten the lifetime of a pyrolysis reactor.

Liquid fuel users require petroleum substitutes such as gasoline, diesel fuel and heavy oil. In these fuels, various additives are often mixed with the liquid hydrocarbons to improve the burner or the engine performance.

The fuel properties such as viscosity and ash content should conform to the specifications of the fuel user's burners or engines. No additives would be needed for fuel used in a boiler. Skillful operators and a well-equipped facility are required due to the formation of highly flammable liquids and gases. Pyrolysis refers to the thermal decomposition of matter with an inert gas like nitrogen.

Depending on the pyrolysis conditions and the type of plastic used, carbonous matter gradually develops as a deposit on the inner surface of the reactor. The resulting oil mixture of liquid hydrocarbons is continuously distilled once the waste plastics inside the reactor are decomposed enough to evaporate upon reaching the reaction temperature.

The evaporated oil is further cracked with a catalyst. The boiling point of the produced oil is controlled by the operating conditions of the reactor, the cracker and the condenser. In some cases, distillation equipment is installed to perform fractional distillation to meet the user's requirements.

After the resulting hydrocarbons are distilled from the reactor, some hydrocarbons with high boiling points such as diesel, kerosene and gasoline are condensed in a water-cooled condenser. The liquid hydrocarbons are then collected in a storage tank through a receiver tank. Gaseous hydrocarbons such as methane, ethane, propylene and butane cannot be condensed and are therefore incinerated in a flare stack. This flare stack is required when the volume of the exhaust gas emitted from the reactor is expected to be large.

The easiest way is to simply introduce the waste plastics into the reactor without any pretreatment. Soft plastics such as films and bags are often fed through a shredder and a melter hot melt extruder before being fed into the reactor because of the large volume they would otherwise occupy.

Figure 2. There are also different types of reactors and heating equipment. Both kiln-type and screw-type reactors have been proposed, while induction heating by electric power has been developed as an alternative to using a burner.

Due to the formation of carbonous matter in the reactor, which acts as a heat insulator, in some tank reactors the stirrer is used to remove the carbonous matter rather than for stirring.

Energy consumption and plant costs relative to plastic treatment capacity are the typical criteria for evaluating the performance. Operating skill and safety considerations are important in this type of chemical conversion due to the highly flammable liquid fuels which are formed. Gaseous hydrocarbons become the main product after residing in the reactor for an extended time at a reaction temperature under controlled decomposition conditions and the use of a specific reactor.

Under specific conditions, carbon and carbohydrates can be used as feedstock for the production of gaseous fuel like methane and hydrogen.

Depending on the types of reactors and reaction conditions, carbonous matter and carbon dioxide are formed, and nitrogen from air is contained in the product gas.

The gasification reactors to be used are moving-bed, fluidized-bed and entrain-bed reactors. If the product is to be stored, a large gas holder is to be required. Several manufacturers have proposed small-scale gasification systems.

Careful cost analysis is important with respect to the amount of collected waste, the transportation distance and the commercial value of the resultant products such as electricity and gaseous fuel.

In any case, this technology requires skillful operators and careful handling to avoid hydrogen explosion. Hydrogen also oxygen or air forms from hydrocarbons and carbohydrates. One is a mixture of gaseous hydrocarbons such as methane and ethylene while the other is synthetic gas - a mixture of hydrogen and carbon monoxide. Table 5. Liquid hydrocarbon like benzene and toluene. The rate of cracking and the end products are strongly dependent on the temperature and presence of any catalysts.

Cracking, also referred to as pyrolysis, is the breakdown of a large alkane into smaller, more useful alkanes and an alkene. Simple hydrocarbon cracking is the process of breaking long chain hydrocarbons into short ones. The process was first used in around and employs a powdered catalyst. During the Second World War, it provided Allied Forces with plentiful supplies of gasoline and artificial rubber that contrasted with the penury suffered by the Axis Forces.

Initial process implementations were based on a low activity alumina catalyst and a reactor where the catalyst particles were suspended in a rising flow of feed hydrocarbons in a fluidized bed. Alumina-catalyzed cracking systems are still in use in high school and university laboratories in experiments concerning alkanes and alkenes. The catalyst is usually obtained by crushing pumice stones, which contain mainly aluminium oxide and silica into small, porous pieces.

In the laboratory, aluminium oxide or porous pot must be heated. In newer designs, cracking takes place using a very active zeolite-based catalyst in a short-contact time vertical or upward sloped pipe called the "riser". The hot catalyst vaporizes the feed and catalyzes the cracking reactions that break down the high molecular weight oil into lighter components including LPG, gasoline, and diesel.

The catalyst-hydrocarbon mixture flows upward through the riser for just few seconds and then the mixture is separated via cyclones. The catalyst-free hydrocarbons are routed to a main fractionator for separation into fuel gas, LPG, gasoline, naphtha, light cycle oils used in diesel and heavy fuel, and heavy fuel oil. The "spent" catalyst then flows into a fluidized- bed regenerator where air or in some cases air plus oxygen is used to burn off the coke to restore catalyst activity and also provide the necessary heat for the next reaction cycle, cracking being an endothermic reaction.

The "regenerated" catalyst then flows to the base of the riser, repeating the cycle. The gasoline produced in the FCC unit has an elevated octane rating but is less chemically stable compared to other gasoline components due to its olefinic profile. Olefins in gasoline are responsible for the formation of polymeric deposits in storage tanks, fuel ducts and injectors. The FCC LPG is an important source of C3-C4 olefins and isobutane that are essential feeds for the alkylation process and the production of polymers such as polypropylene.

This can be done with a thermic or catalytic method. The thermal cracking process follows a homolytic mechanism, that is, bonds break symmetrically and thus pairs of free radicals are formed. The catalytic cracking process involves the presence of acid catalysts usually solid acids such as silica-alumina and zeolites which promote a heterolytic asymmetric breakage of bonds yielding pairs of ions of opposite charges, usually a carbocation and the very unstable hydride anion.

Carbon-localized free radicals and cations are both highly unstable and undergo processes of chain rearrangement, C-C scission in position beta i. The chain of reactions is eventually terminated by radical or ion recombination.

Modern high-pressure thermal cracking operates at absolute pressures of about 7, kPa. An overall process of disproportionate can be observed, where "light", hydrogen-rich products are formed at the expense of heavier molecules which condense and are depleted of hydrogen.

The actual reaction is known as homolytic fission and produces alkenes, which are the basis for the economically important production of polymers. A large number of chemical reactions take place during steam cracking, most of them based on free radicals. Computer simulations aimed at modeling what takes place during steam cracking have included hundreds or even thousands of reactions in their models.

The main reactions that take place include: Initiation reactions, where a single molecule breaks apart into two free radicals. Only a small fraction of the feed molecules actually undergo initiation, but these reactions are necessary to produce the free radicals at drive the rest of the reactions. In steam cracking, initiation usually involves breaking a chemical bond between two carbon atoms, rather than the bond between a carbon and a hydrogen atom.

This is the process that results in the alkene products of steam cracking. These processes are involved in forming the aromatic products that result when heavier feedstock are used.

Two common forms of termination are recombination, where the two radicals combine to form one larger molecule, and disproportionation, where one radical transfers a hydrogen atom to the other, giving an alkene and an alkane. Pyrolysis is a special case of thermolysis, and is most commonly used for organic materials, being then one of the processes involved in charring.

In general, pyrolysis of organic substances produces gas and liquid products and leaves a solid residue her in carbon content. Extreme pyrolysis, which leaves mostly carbon the residue, is called carbonization. These specialized uses of pyrolysis may be called various names, such as dry distillation, destructive distillation, or cracking. Pyrolysis also plays an important role in several cooking procedures, such as baking, frying, grilling, and caramelizing.

It is also a tool of chemical analysis, for example in mass spectrometry and in carbon dating. Indeed, many important chemical substances, such as phosphorus and sulfuric acid, were first obtained by this process. Pyrolysis has been assumed to take place during catagenesis, the conversion of buried organic matter to fossil fuels. It is also the basis of pyrography. Pyrolysis differs from other high-temperature processes like combustion and hydrolysis in that it does not involve reactions with oxygen, water, or any other reagents.

However, the term has also been applied to the decomposition of organic material in the presence of superheated water or steam hydrous pyrolysis , for example in the steam cracking of oil.