Auger reactor for processing plastic waste into liquid fuel

Abstract

The pyrolysis process of plastic waste into liquid fuel is currently experiencing production capacity problems because the plastic waste contains many impurities. The impurities in the plastic waste will be processed into charcoal. The pyrolysis process also produces ash. The charcoal and ash produced must be removed periodically to maintain the reactor's capacity. This invention relates to pyrolysis equipment that can quickly remove residual ash and charcoal without waiting for the reactor to cool down. The auger reactor is a horizontal cylinder heated from the bottom of the reactor, and plastic waste is continuously fed from the side. This reactor has a horizontal spiral-shaped auger, which stirs plastic waste during the conversion process and pushes impurities to the reactor exit during the charcoal and ash cleaning stage. The discharge of pyrolysis steam from the reactor is also equipped with vertical tubes so that fine impurities can fall back into the reactor. Pyrolysis steam is condensed by an indirect cooling process outside the reactor to produce pyrolysis oil. The gas from the pyrolysis steam that is not condensed can be burned to be used as a heat source for the pyrolysis process.

Description

[0001] Description

[0002] AUGER REACTOR FOR PROCESSING PLASTIC WASTE INTO LIQUID FUEL

[0003] Technical Field of the Invention

[0004] This invention relates to an auger reactor for the pyrolysis of plastic waste , which usually contains impurities , into liquid fuel . Speci fically, the reactor in this invention is equipped with an auger that can rotate back and forth when operating .

[0005] Background of the Invention

[0006] Plastic waste is a common problem in big cities worldwide . Such waste continues to accumulate over time . Thus , it is necessary to find a solution . Moreover, the depletion of fossil energy sources , such as oil and coal , and the pollution they produce also require a solution . Converting plastic waste into liquid fuel is one solution that can simultaneously solve these two problems .

[0007] The conversion of plastic waste into fuel is known as pyrolysis technology . In this process , plastic waste is heated to high temperatures in the absence of oxygen so that plastic polymer molecules decompose into smaller hydrocarbon molecules , such as gas and liquid fuel , as the main product . From this point onwards , we will refer to this liquid fuel as pyrolysis oil . Moreover, the pyrolysis of plastic waste will produce by-products in the form of Ci s / d C4 gasses , which, when fractionated and combined, can be commerciali zed into LPG and CNG .

[0008] Unfortunately, although the technology has been widely developed, less attention was paid to the fact that the plastic waste to be processed contains many impurities . Separating charcoal and residual ash from the pyrolysis of dirty plastic waste is a problem as it requires cooling time before operators can safely remove it . The present invention allows the removal of charcoal and residual ash from the pyrolysis process to be done quickly, safely, and without cooling the reactor . This invention relates to pyrolysis equipment with the auger reactor system, as expressed in several patents. One of the patents is No. KR 20,220,070,548 titled "Char separator and method" using an auger-type reactor. However, its disadvantage is that it requires a long combustion chamber because the stirrer only rotates in the same direction. Another patent is No. US 102,246, 643 B2 titled "Process and apparatus for producing hydrocarbon fuel from waste plastic." However, its disadvantage, among others, is that there are too many moving tools in contact with the heat medium, such that it has low resistance and requires lots of energy.

[0009] Another patent is No. WO 2,019,004,560 Al titled "Apparatus for recycling a plastic mixture containing polyvinyl chloride, and a method for recycling a plastic mixture containing polyvinyl chloride by using the same." This patent's disadvantage is related to the raw materials used as it requires lots of energy and a temperature of 700°C. It is also complicated because it needs to heat two types of reactors.

[0010] Another patent is No. WO 2,022,197, 696 Al titled "A two-step process for chemically recycling plastic waste." However, its disadvantage is that it requires uniform feed size as it uses a fluidized bed reactor. Moreover, this system uses lots of energy as it needs to heat the fluidized bed to 700°C, requires expensive types of catalysts, and is complicated to use because it requires a catalyst regeneration system.

[0011] The present invention uses a stirred reactor with a radial rotation to spread the heat evenly. The incoming feed does not have to be uniform in size because it uses a stirred reactor. This spiral auger can rotate unidirectionally to push the charcoal and ash to the reactor exit. Thus, the reactor can be stopped for a short while because the charcoal and ash can be removed quickly, and it does not require waiting time for the reactor to cool down. These advantages are different from the plastic waste pyrolysis equipment circulating in the Indonesian market, where operators must wait for the reactor to cool down to remove ash and charcoal from the reactor. Summary of the Invention

[0012] This invention aims to overcome existing problems and improve the ef ficiency of the plastic waste conversion process to liquid fuel or pyrolysis oil using an auger reactor .

[0013] An auger reactor that pyrolyzes plastic waste into liquid fuel comprises several components including a hori zontal cylindrical reactor, a waste combustion chamber, and a spiralshaped auger that stirs plastic waste during pyrolysis and periodically pushes charcoal and ash out of the reactor . The auger is located inside the reactor and moves in concentric angles with the reactor, and the stirring motor is located outside to increase its durability . It also contains a continuous feeder that functions to enter plastic waste into the hori zontal pyrolysis reactor and stops during the ash / charcoal discharge process . Next , the ash / charcoal exit , vertical tube , condenser, and plastic oil product tank all function to accommodate the plastic oil product . This tank is located after the condenser . The liquid ring vacuum pump draws pyrolysis steam from the reactor and maintains the system ' s vacuum state . The position of this vacuum pump is after the plastic oil product tank . The present invention also includes a pyrolysis oil trapper that traps pyrolysis oil in the condensed steam from the vacuum pump . The pyrolysis gas burner also burns pyrolysis gases in the combustion chamber . This burner is a hori zontal pipe under the combustion chamber with holes along the pipe so that the gas product will be evenly dispersed and burn evenly in the combustion chamber . Moreover, the auger in this invention can rotate back and forth when operating . The auger is equipped with an iron brush at the end of its blade to fill the gap and can be used to push the charcoal / ash to the exit of the reactor, where the discharge of charcoal and ash can be done when the reactor is hot and does not require the reactor to cool down . Brief Description of the Figures

[0014] Figure 1 is a schematic diagram of an auger reactor for pyrolyzing plastic waste into liquid fuel per this invention.

[0015] Figure 2 is a side view (a) , top view (b) , and perspective view (c) of a horizontal auger in the reactor to pyrolyze plastic waste into liquid fuel per this invention.

[0016] Description of the Invention

[0017] This invention aims to solve the low daily processing capacity of plastic waste conversion into fuel due to the long period required to remove ash and charcoal from the reactor. The long cool-down period for the reactor is required so that the operator can safely open the reactor to remove ash and charcoal. This cooldown period does not allow the process to continue to occur. The innovation of an auger reactor with horizontal axles enables the ash and charcoal to be ejected quickly and safely.

[0018] Figure 1 is a schematic diagram of an auger reactor for pyrolyzing plastic waste into liquid fuel. The reactor consists of a horizontal reactor cylinder (1) , which serves as a place for the pyrolysis of plastic waste into steam pyrolysis oil; the trash combustion chamber (2) , where trash is burned for pyrolysis. The combustion chamber is located at the bottom of the pyrolysis reactor (1) to maximize the heat delivered. The auger (3) stirs the plastic waste during pyrolysis and periodically pushes the charcoal and ash out of the reactor. It is located in the reactor (1) and works concentrically with the reactor (1) . The stirrer's motor is located on the outside to ensure its durability; The continuous feeder (4) , enters the waste plastic into the horizontal pyrolysis reactor (1) continuously and stops when the ash / charcoal is expelled. The feeder is located before the reactor (1) ; the ash / charcoal exit (5) , serves as the place for periodically issuing ash / charcoal. The door is located at the bottom of the reactor (1) so the ash exiting the reactor would follow gravity; A vertical tube (6) serves as an exit for steam products and prevents ash or charcoal in the steam pyrolysis from falling back into the reactor. The vertical tube is connected to the reactor (1) and is in the middle of the upper part of the reactor tube. It can also be used as a catalyst (1) ; The condenser (7) , condenses the oil fraction from the pyrolysis steam. The condenser is located after the reactor's output (1) ; The product tank for the pyrolysis oil (8) accommodates the plastic oil product. The tank is located after the condenser (7) ; A vacuum pump liquid ring (9) , serves to draw pyrolysis steam from the reactor (1) and keeps the system always in a vacuum state. The vacuum pump is located after the plastic oil product tank (8) ; A pyrolysis oil trapper (10) traps the pyrolysis oil in the condensed steam coming out of the vacuum pump (9) ; A pyrolysis gas burner (11) burns pyrolysis gases in the combustion chamber. This burner is in the form of a horizontal pipe and is located under the combustion chamber with holes along the pipe so that the gas product will be evenly dispersed and will burn evenly in the combustion chamber (2) ; An auger (3) can rotate back and forth when operating, and at the end of the auger, there is a blade (3) equipped with an iron brush to fill the gap and can be used to push the charcoal / ash to the exit of the reactor.

[0019] The pyrolysis process of plastic waste begins by feeding plastic waste into the reactor by pushing the accumulated plastic waste into the continuous feeder system (4) . The pushed plastic waste will solidify and form a barrier wall so that outside air cannot enter the reactor through this feeder line and vice versa. It prevents the backflow of the product's hot steam from going through the feeder line. Due to the heat generated in the waste combustion chamber, the plastic waste will be pyrolyzed and evaporated upward toward the reactor tube (6) . The plastic oil vapor will then flow to the condenser (7) as it is drawn by the vacuum pump (9) . The cooling water flowing into the condenser (7) will condense the plastic oil fraction present in the steam. This plastic oil is then collected in a plastic oil reservoir (8) . Meanwhile, a vacuum pump will draw the gas fraction and spray it into a plastic oil trapper. The goal is to obtain the fraction of plastic oil still inside the uncompensated gaseous products. After exiting this device, the remaining gas is a stream of uncompensated gaseous products that can be burned in the waste combustion chamber (2) to generate heat for the pyrolysis process.

[0020] This system is divided into the following 3 (three) parts:

[0021] 1. Preparation process

[0022] Ensures all supporting equipment is running correctly and ready for operation. Plastic waste, ready-to-burn garbage, and cooling water are sufficiently available. The vacuum pump can work well, and no leaks allow air to enter the reactor.

[0023] 2. Pyrolysis process

[0024] The waste is burned in the combustion chamber, and the smoke is sucked in by a suction fan so that the combustion chamber is always in a slightly vacuum state. Plastic waste introduced by the feeder continuously (4) will melt and undergo pyrolysis due to its contact with the reactor's hot walls (1) . The pyrolysis process will run well at a temperature range of 300-450°C. The plastic waste depolymerization process occurs in the reactor (1) , where plastic waste is heated at 300-450°C in the absence of oxygen. The time required can range from 30 minutes to 4 hours, depending on the temperature and composition of the plastic waste.

[0025] Plastic waste molecules will be depolymerized into shorter molecules into pyrolysis steam. This steam is then condensed into plastic oil. There are also non-condensed products, such as methane gas, CO, hydrogen, and more. The higher the pyrolysis temperature, the more gas components are formed and the faster the depolymerization process. However, the pyrolysis oil produced contains a high amount of wax. The lower the pyrolysis temperature, the fewer gas components produced, and the pyrolysis oil produced will contain less wax. However, the depolymerization process will also be slower. Not all plastic waste will be depolymerized; some will become charcoal and ash and be left in the reactor.

[0026] For the pyrolysis process to run correctly, the auger (3) is rotated back and forth to flatten the plastic waste in the reactor so that all the waste can have good contact with the hot reactor wall. The pyrolyzed plastic waste will evaporate, and the steam is drawn by a vacuum pump ( 9 ) . The pressure conditions in the reactor ( 1 ) are always maintained in a s light vacuum state to prevent the leakage of pyrolysis vapors into the chamber . The reactor chamber has a vertical tube cylinder ( 6 ) at the top, a path for the pyrolysis steam discharge to enter the condenser . This reactor tube allows the solid impurities from the pyrolysis steam to have enough time to fall back into the reactor . Another function of this reactor tube is as an inspection hole for inspectors to conduct reactor maintenance .

[0027] As seen in Figure 1 , the heating process is conducted by combusting the waste and gaseous products that are fed back into the combustion chamber ( 2 ) . To ensure complete combustion, the smoke from the combustion process is always sucked in by a suction fan to absorb atmospheric air to create excess oxygen conditions in the combustion chamber . The air enters the combustion chamber through air holes . This combustion chamber is always kept at a slight vacuum condition to prevent gas heat from the combustion chamber from exiting the combustion chamber door .

[0028] The auger ( 3 ) with hori zontal axles , as seen in Figure 2 , stirs the incoming plastic waste in the reactor by rotating back and forth so that the plastic waste would have even contact with the hot wall . This spiral-shaped auger also removes ash and charcoal from the reactor when this material has accumulated .

[0029] 3 . Product cooling and storage process

[0030] The hot steam exiting the reactor is then cooled indirectly by the condenser to collect the liquid fuel from some of the condensed pyrolysis oil steam . This hot steam is cooled to temperatures below 50°C so that less hot steam is sucked into the vacuum pump and mixed with water . The pyrolysis oil formed is then collected in the product tank ( 8 ) for precipitation . In the product tank, the water condenses with the pyrolysis oil , separates , and settles at the bottom . The pyrolysis oil is lighter and will float on the water fraction .

[0031] Another cooling process is in the pyrolysis oil trap ( 10 ) , where the steam from the pyrolysis oil undergoes direct contact with the cooling water . The pyrolysis oil fraction in the steam that did not condense in the condenser will do so at thi s stage and mix with the cooling water . The pyrolysis oil will separate and float on the cooling water .

[0032] 4 . The combustion process of the gas fraction that has not condensed .

[0033] After cooling in the pyrolysis oil trapper, there are uncondensed gases : fractions of cl -c4 . These gases have a high calori fic value and can be used as a heat source for the pyrolysis process by sending it to the pyrolysis gas burner chamber . At a speci fic temperature , an equilibrium will be reached between the gases produced and the heat requirements of the pyrolysis process . At this temperature , the process no longer requires waste as fuel and can even result in a gas surplus . This equilibrium temperature ranges between 400 and 450°C, depending on the plastic waste composition, moisture content , and impurities present . In the future , these gases can be exploited for commerciali zation .

[0034] 5 . Ash and charcoal production process .

[0035] The pyrolysis process of plastic waste will produce residual charcoal and ash that cannot be depolymeri zed into a vapor phase and remain in the reactor . Other impurities that enter the plastic waste will also be le ft in the reactor . This material will accumulate in the reactor and must be periodically removed to not impair the pyrolysis processing capacity . After the reactor has been processed for 6-24 hours ( depending on the level of impurities and waste composition) , the removal process of impurities must be performed .

[0036] The removal process is as follows : a . The entry of new material into the reactor is stopped . b . The operator must wait for all materials in the reactor to turn into charcoal and ash . Over time , the temperature in the reactor will continue to drop because the pyrolysis steam that heats the temperature sensor will decrease . c . Stop the intake of fuel into the combustion chamber . d. Spray water into the reactor to form steam and push the remaining non-condensed gas toward the condenser. e. Open the ash / charcoal exit door (5) . f. Rotate the auger (3) in the direction of pushing the ash and charcoal towards the ash / charcoal exit (5) . g. Once all the ash / charcoal has been removed, close this door again and restart the pyrolysis process.

[0037] Table 1 below shows the differences in the productivity of pyrolysis reactors with horizontal spiral stirrers compared to conventional reactors. The table below shows that productivity can be increased by 46% because the spiral-stirred reactor does not require cooling time when it emits ash and charcoal.

[0038] Table 1. The loading factor differences of plastic waste pyrolysis reactors.

Claims

Claims1. An auger reactor to pyrolyze plastic waste into liquid fuel, which consists of: a horizontal cylinder reactor (1) , which functions as a place to pyrolyze plastic waste into pyrolysis oil steam; a waste combustion chamber (2) , which incinerates waste for pyrolysis, and is located under the pyrolysis reactor (1) to maximize the heat delivered; an auger (3) , which stirs plastic waste during pyrolysis and pushes charcoal and ash out of the reactor at regular intervals, is located inside the reactor (1) and has concentric axles with the reactor (1) , while the stirring motor is outside the reactor for better motor durability; a continuous feeder (4) that continuously enters plastic waste into the horizontal pyrolysis reactor (1) and stops during the ash / charcoal removal process, and the feeder (4) is placed before the reactor (1) ; an ash / charcoal exit door (5) removes ash / charcoal periodically, is located at the bottom of the reactor (1) to allow the exiting ash to follow gravity; a vertical tube (6) that functions as an exit for the product's steam and prevents ash or charcoal pyrolysis steam from falling back into the reactor, it is located in a same section as the reactor (1) and is in the middle of the top of the reactor, which it can also be used as a catalyst (1) ; a condenser (7) that condenses the oil fraction in the pyrolysis steam, and is located after the reactor output (1) ; a plastic oil product tank (8) that accommodates plastic oil products, and it is located after the condenser (7) ; a liquid ring vacuum pump (9) that draws pyrolysis steam from the reactor (1) and maintains the system to always be in a vacuum state, and it is positioned after the plastic oil product tank (8) ;a pyrolysis oil trap (10) that traps pyrolysis oil in the condensed steam coming out of the vacuum pump (9) ; a pyrolysis gas burner (11) that burns pyrolysis gases in the combustion chamber, which is a horizontal pipe under the combustion chamber with holes along the pipe to ensure that the gas products will be evenly distributed and will burn evenly in the combustion chamber (2) ; and characterized with an auger (3) that can rotate back and forth when operating, and a blade (3) equipped with an iron brush at the end of the auger to fill the gap and can be used to push the charcoal / ash to the reactor's exit.

2. An auger reactor to pyrolyze plastic waste into liquid fuel of Claim 1, where charcoal and ash can be discharged when the reactor is hot and does not require the reactor to cool down.

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