TWI305787B - Device and process for plastic pyrolysis - Google Patents

Description

305787 IX. INSTRUCTIONS: [Technical field of invention] The present invention relates to a method for cracking plastic and a plastic cracking device, particularly relating to a method for improving oil liquefaction rate and reducing chlorine content in oil products. Plastic method and plastic cracking device. [Previous technology #f] The annual output of discarded plastics in China is about one million taunts, and the φ 16% of household waste is significantly higher than that of Europe (8%) and the United States (7%). Waste plastics are made of a variety of different plastics, including: polyvinyl chloride (p〇lyvinyl chbride, PVC), polyethylene (polyethylene, PE), polypropylene (p〇lypr〇pyiene, pp), polystyrene ( Polystyrene, PS), Acrylonitrile Butadiene Styrene (ABS), Phenolic, Urea, Melamine, Ep0Xy, Unsaturated Polyester and Polyurethane. China's waste plastics processing plant can handle about 710,000 towns of waste plastics per year, accounting for about 7% of total waste plastics, while the types of plastics processed are concentrated in thermoplastics such as PVC, PP, PE, PS or ABS, etc. Early degradation of waste plastics is generally based on PE, PS, and PP, and less on the degradation mechanism of pvc. Over the past two decades, the rate of increase in waste plastics has far exceeded the rate of plastic production. Such a large amount of plastic waste, if disposed of by incineration, will cause environmental pollution and waste of resources. Among the many halogen-containing plastics, polyvinyl chloride (polyvinyl 〇718-A21362TWF(N2); P1〇94〇〇35TW; shine 5 ϋ〇5787 chloride PVC) has low cost, good processability, heat resistance and flame resistance. Excellent electrical insulation' = and good chemical resistance, so it is widely used in various industries, and the output and usage are extremely large, so a large amount of pvc waste is generated, which causes quite troublesome environmental protection problems. Traditionally, thermal cracking technology has been used to treat waste plastics, and organic wastes have been converted to liquid fuels for recycling, so as to avoid direct discharge of waste or disposal in the environment. The so-called thermal cracking refers to thermal decomposition at an appropriate temperature and under anoxic conditions, in which the structure of the polymer breaks into smaller intermediates and intermediate products. These intermediates can be used as petrochemical industry. Use fuel or raw materials for recycling purposes. Thermal cracking can handle many types of homing and dope with other materials such as wood, paper or paint, and does not increase the volume of each gas, nor does it cause Dioxin X emissions. However, because the waste plastic is doped with many plastics containing halogen components, such wastes will produce poisonous and rot-toothed tooth nitrogen during the cracking process, causing the corruption of the cracking furnace and related equipment, and will affect The quality of liquid fuel and its response have become the biggest problem in dealing with waste transfer process towels. Figure 1 (d) is a conventional plastic disintegration device (10) comprising a cracking tank ιοί, a feed supply tank in, a nitrogen supply tank 113, a condenser (10), a valve (2), a crucible I23, and a line m. The waste plastic is placed in the feed supply tank (1), and is supplied to the cracking tank 1〇1 in a batch manner, and the nitrogen gas supplied from the nitrogen supply tank 113 is mixed, and the cracking tank 1Q1 is discarded and discarded. The organic gas obtained after degrade) is sent to the condenser 105 for condensation by the line ι 6 (10), and the uncondensable gas is discharged through the crucible 123, and the condensate is discharged through the 0718-A21362TWF (N2); P10940035TW; the shine 6 1305787 valve 121. And get liquid oil. The above liquid oil can be used as _ oil (four). However, if PVC is contained in the waste plastic, hydrogen chloride will be produced during the cracking process, causing cracking furnaces and other impurities, which will affect the quality of the liquid oil and limit its application. In order to reduce the chlorine content in the oil, all parties are committed to research to improve this issue.

The 9^ leak 1187 patent proposes a waste dechlorination process, which is a circulating fluidized hearth by heating the waste plastic to 25 〇 35 〇. 〇, the chlorine component of the plastic is released in the form of HC1, and then absorbed by the test liquid to achieve the purpose of degassing. The US6346220 patent provides the movement of waste plastics in a dechlorination furnace and supplies its heat by means of a rotating blade in a dechlorination furnace for thermal decomposition. The US4031192 patent separates HC1 by superheated steam in a closed container by using waste pvc plastic or chlorine-containing waste plastic. JP2〇00191826 patent provides a waste plastic thermal cracking recovery gas and oil device. The cracked gas is collected from the top of the tank. The extracted oil is collected from the bottom, and the cracking temperature is controlled at 350~45 (TC, The chlorine-containing component in the oil is absorbed and removed by using iron oxide as a catalyst. The JP06065585 patent focuses on mixing chlorine-containing waste plastics and catalysts and feeding them in a screw feeder, while the catalyst is oxidized. Nickel, cerium oxide, zinc oxide, chromium oxide. JP07192499 patent by adding catalyst (complex compound) in the cracking process of waste plastics and controlling the temperature at 150~400 °C, and the chlorine component in the oil will 0718-A21362TWF(N2);P 10940035TW;shine 7 1305787 is adsorbed by the catalyst in the form of HC1. The CN2649590 patent uses chlorine-containing waste plastics with 200~40 (TC heat medium (which is water vapor or water vapor and other non- The mixed gas of oxidizing gas is directly heated in the reactor, and the obtained HC1 solution and the dechlorinated waste plastic can be recycled and reused. The TW294686 patent proposes a thermal cracking method for plastic waste. Thermally cracking a molten plastic in a cracking vessel, and sending the formed gaseous product into a branch to separate the south boiling point product, harmful gas, non-condensable hydrocarbon gas and low-folk point product, and the harmful gas, non-condensable hydrocarbon The gas and the low boiling point product are fed to a kiln-containing calciner. When the high-boiling product is reheated, part of the reheated high-boiling product is recycled to the above-mentioned thermal cracking vessel', and the residual portion is sent to the zeolite catalyst layer for catalytic conversion. The residue formed by thermal cracking of the plastic waste in the thermal cracking step is taken from below the thermal cracking vessel. - TW445273 patent partially oxidizes the plastic cracking oil by reacting in a reaction zone of a quenching gasifier, wherein the cracking oil Is used as a main hydrocarbon reactant in a non-catalytic partial oxidation reaction to form a synthesis gas containing hydrogen halide, and quenching the synthesis gas, which is quenched in the quenching zone of the gasifier Wherein the syngas system is contacted with quench water containing sufficient neutralizing agent to coagulate and t and the hydrogenated hydrogen in the synthesis gas, thereby forming a separation and recovery from the quench water The condensed halogenated salt and the synthetic gas which is substantially free of dentate. However, the device or the step of the above patent is complicated, and the liquefaction rate of the oil and the removal effect of the halogen component are limited. [Summary of the Invention] 0718-A21362TWF(N2); Pl0940035TW; One of shine 8 is to provide a catalyst and absorbent for cracking plastics to reduce the quality and reduce the chlorine content to the environment.

1305787 In view of this, the method of the present invention enhances the ecological ecology of the oil by increasing the chlorine content of the oil during the cracking process. Another object of the present invention is to provide a method for cracking plastics by using (four) medium and absorbent in the cracking process to reduce the average carbon number, carbon number distribution and cracking time in the oil to enhance the oil product. And reduce energy consumption. The purpose of this month is to provide a method for cracking plastic, which is used to crack the waste plastic in a two-stage manner, and the use of the catalyst and the absorption enthalpy in the thermal cracking process to enhance the liquefaction rate of the oil and reduce the oil. The chlorine content in the oil makes the oil quality good and is more suitable for fuel or chemical raw materials. According to the above object, the present invention provides a plastic cracking device comprising a first cracking tank, a second cracking tank and a condenser. The first cracking tank is used for marrying and melting a halogen-containing plastic to form a mixture comprising hydrogen halide and teeth. Hydrocarbon generation, the second cracking tank is connected to the first cracking tank for accommodating Fe〇(〇H) and CaC03, wherein Fe〇(〇H) is used as a catalyst to decompose halogenated hydrocarbons to form halogen-free hydrocarbons. And a halogen component 'CaC03 as a first absorbent for absorbing hydrogen halide and a halogen component, and the condenser is connected to the second cracking tank. The present invention provides a method of cracking a plastic comprising: (a) providing a halogen-containing plastic, (b) cracking a halogen-containing plastic between 300-550 QC to form a mixture comprising a hydrogen halide and a halogenated hydrocarbon, (c) at 330 Between -420GC

FeO(OH) decomposes halogenated hydrocarbons to form halogen-free hydrocarbons and halogen components, and (d) absorbs hydrogen halide and halogen 0718 between 33 0 and 42 (by CaC03 and/or Ca(OH)2). A21362TWF (N2); P10940035TW; shine 9 1305787 into $, (e) mixture after the steps (c) and (d) 'transformed into a gaseous mixture with the first oil, and (f) condense the gaseous mixture to obtain the first [Embodiment] The thermal cracking reaction shows that the solid or liquid organic matter is heated in an oxygen-deficient environment, causing the chemical bond of the organic substance to break and decompose, and the sub-chain of some organic substances will be lightly in the appropriate ring. She, the shape of the money machine (four). Partial organic

: The quality remains in a low molecular state 'after a series of physical and chemical reactions, including gas phase hydrogen carbide, water vapor, solid residue containing fixed carbon charcoal (Fked (10) (10) ^, char (Char) and ash. If the appropriate condensation process is followed, the product of the milk phase will appear as a liquid oil and water. In general, the rate is higher than that of the (four) thermal decomposition reaction, and the resulting gas contains a small amount of gas. The product is mainly oil and coke. From a chemical point of view, the thermal cracking reaction can be expressed by the following formula: volatiles + coke + ash organic matter (solid or liquid) - volatiles ~ ~ gas + oil + water The thermal enthalpy can be divided into two types: pure thermal cracking and modified thermal cracking. Early pure thermal cracking refers to the lack of *preparation / heat, the correction _ solution = or the environment, (four) connected to the heating刼 斗 斗 疋 疋 疋 疋 以 以 以 以 以 以 以 以 以 以 以 以 以 以 以 以 以 以 以 以 以 以 以 以 以 以 以 以 以 以 以 以 以 以 以 以 以 以 以 以 以 以Direct heating) simple thermal cracking (indirect heating;) heat transfer Higher __ depends on intermediate heat transfer objects such as furnace walls, etc., 埶0718-A2i362rWF(N2); Pt0940035TW;shine 10 1305787 ---____ no need to borrow heat from the furnace wall, the maximum temperature can reach about 12〇〇°c The heat transfer by the furnace wall is required, and the material requirements are relatively high. The maximum wall temperature is only about 900qC. The furnace wall will not undergo significant thermal expansion. The heat preservation: the material lining will not fall off the furnace wall and significant thermal expansion will occur. The insulation and refractory lining will be better. It is easy to fall off all the combustion air for heating and the volatile gas generated by the reaction, so the flue gas treatment equipment is too large - the combustion air for heating and the volatile gas generated by the reaction can be treated separately, so the latter part of the flue gas treatment is smaller. The two thermal cracking methods have their own advantages and disadvantages. Therefore, different cracking methods can be selected according to actual needs. The cracking tank in one embodiment of the present invention uses simple thermal cracking in an environment containing an inert gas through indirect heating. The main components of the plastic cracking device in one embodiment of the present invention are described below. Please refer to FIG. 2a, which illustrates the present invention. The plastic cracking device 200a in the embodiment includes a first cracking tank 201, a second cracking tank 203, a condenser 205, a feed supply tank 211, an inert gas supply tank 213, a line 215 Lu and 217, and valves 219, 221 and 223. The feed supply tank 211 is connected to the first cracking tank 201, and the inert gas supply tank 213 is connected to the first cracking tank 201. The first cracking tank 201 and the second cracking tank 203 are connected by a line 215, and the second The cracking tank 203 and the condenser 205 are connected by a line 217, the valve 219 is disposed at the bottom of the second cracking tank 203, and the valve 223 and the valve 221 are respectively disposed at the top and the bottom of the condenser 205. Referring to Figure 2b, there is shown a plastic cracking apparatus 200b in an embodiment of the present invention, wherein most of the components are the same as the plastic cracking apparatus 200a, and will not be described herein. The difference is that in the plastic cracking device 200b, Π 0718-A21362TWF (N2); P10940035TW; shine 1305787 further includes an absorption tank 225' disposed between the second cracking tank 203 and the condenser 205. The absorption tank 225 is connected to the first cracking tank 203 by a line 217a, and the absorption tank 225 is connected to the condenser 205 by a line 217b. The plastic cracking apparatus 200a will be used hereinafter to explain the implementation steps of the splitting plastic in the present invention. First, another inert gas such as nitrogen gas is supplied from the inert gas supply tank 213 into the first cracking tank 201 for about 1 minute to contain nitrogen gas, and then the supply is stopped. It should be noted that the invention is not limited thereto, and it is also possible to continue supplying nitrogen during the subsequent thermal cracking. Next, the gas-containing plastic is pulverized and placed in the feed supply tank 211, and is supplied to the first cracking tank 2〇1 in a batch manner under a normal pressure or a micro-negative pressure state, but the invention is not limited thereto. Therefore, the plastic feed can also be supplied by continuous feeding. Polyvinyl chloride (PVC) may be included in the chlorine-containing plastic. In an embodiment of the invention, the gas content in the chlorine-containing plastic is preferably not more than 1% by weight, and the chlorine-containing plastic is preferably in the form of particles or chips. Thereafter, at a temperature of 300-550 GC, preferably 420-48 (^: melt-cracking the chlorine-containing plastic located in the first cracking tank 201 to form a mixture, and the mixture includes strontium telluride , the mouse passage (R-C1, or organic gasification) and the chlorine-free tobacco, and the above mixture is transferred to the second cracking tank 2〇3 by the line 215. The chlorine-containing plastic is mainly formed after the thermal cracking. Gaseous and liquid products, gaseous products include short-chain hydrocarbons such as Ha, CH4, C〇, c〇2, etc. Possible reactions and products at different cracking temperatures are as follows: 100 to 2 〇〇gc for dehydration and drying Such as physical changes; 250 ° C or so began to deoxidize, dechlorination, remove crystal water, produce C 〇 2 and produce HC1 gas and other reactions; above 340QC, aliphatic compound 0718-A2t362TWF (N2); P10940035TW; 1305787 begins to work into CH4 and other shorter chain aliphatic hydrocarbons, such as swarf with a carbon number of 1 to 5. The second cracking tank 203 contains FeO(OH) and CaCCVCaC03 as absorbents for absorption. Hydrogen chloride or chlorine to reduce the chlorine content of the oil. FeO(OH) is used as The catalyst 'is used to decompose the bond between the hydrocarbon and chlorine in the chlorinated hydrocarbon (R-C1 bond), so that the cracked chlorine component acts with the absorbent to form Ca(OCl) 2 · 3H 2 〇 or CaCl 2 a compound such as New Zealand to further reduce the chlorine content in the oil. In another embodiment of the present invention, the second cracking tank 2 〇3 has a Ca(OH)2, which is also absorbed. For the purpose of the agent, the absorbent used in the above steps is a reagent grade CaC〇3 with a specific surface area of 15 m2/g, which is supplied by Shiraishi Kogyo Co., Ltd., and the catalyst used in the above step is goethite a_Fe0. (0H) 'The specific surface area is 86 m2/g, which is supplied by T本Toda Kogyo 司 ς: In one embodiment of the present invention, the catalyst and the absorbent can be manufactured by themselves, and the Japanese business TodaKogyo can also be purchased. Products supplied by the company. The catalyst and absorbent are manufactured as follows.

The CaCCV resin was mixed at a weight ratio of 90/10, and 20 wt% of water was added during the mixing to pelletize. The phenol resin is added to increase the mechanical strength of the finished product. The phenol resin used is sold under the trade name Bellpearl S890, supplied by ICaneb. The above mixture containing CaC〇3, a resin and water was sintered in an environment of 500% and an inert gas for 1 hour. Thereafter, cac〇3 and FeO(OH) were mixed at a ratio of Fe/Ca molar ratio of 35/65, and then 15 wt% of phenol resin was added, and the mixture was compressed at 98 Mpa for granulation, particle size. It is 25mm\|/*5mm. The particles were carbonized at 800 GC and then pulverized to screen particles having a particle size of 350-710 um for use in a dechlorination procedure. 0718-A21362TWF(N2); P10940035TW; shine 1305787 The second cracking tank 203 contains FeO(OH) and CaC03, so after the mixture in the first cracking tank 201 is transferred to the second cracking tank 203, the mixture will be At a temperature of 330-420oC, it is preferred to continue cracking at a temperature of 350-3803⁄4. Among them, the catalyst Fe0(0H) decomposes the chlorinated hydrocarbon in the mixture into a gas-free and chlorine-containing component, and the absorbent CaC03 will Hydrogen chloride and chlorine components in the mixture are absorbed. Therefore, the mixture from the first cracking tank 2〇1 is 'transformed into a gaseous mixture and a liquid oil (for convenience, referred to herein as a first oil) after undergoing crack %, decomposition and absorption. The oil is discharged through the valve 219, and the gas mixture is sent to the condenser 205 via line 217 for condensation to obtain another liquid oil (referred to herein as the second oil). The second oil is passed through the condenser 2〇5. The valve 221 at the bottom is discharged, and the gas that cannot be condensed is discharged through the valve 223. In an embodiment of the invention, the chlorine content of the second oil is lower than the chlorine content of the first oil. The liquefaction rate of the gas-containing plastic converted into liquid oil through the above steps can reach 55 wt% or more, and the obtained liquid oil can be used as a chemical raw material or a fuel, and the chlorine content in the mixed liquid oil can be reduced to 〇. 5 wt% or less. Ageing is the implementation of plastics using a plastic cracker. It should be noted that the present invention is not limited thereto, and in another embodiment of the present invention, the plastic cracking device 200b is used to crack the plastic, that is, the self-exhausted gaseous mixture is first (four) before being sent to the condenser 2〇5. The recording tank 225 (please refer to FIG. 2b) 'takes the trace amount of nitrogen chloride or chlorine contained in the gaseous mixture _ further into the condenser and then transfers it to the condenser 2〇5. Absorbent materials such as CaC〇3 and/or Ca(OH)2 may be included in the absorption tank milk. Further, the absorption tank 225 may be disposed between the first cracking tank 2〇1 and the second cracking tank 2〇3 (not shown). 0718-A21362TWF (N2); P 10940035TW: shine 1305787 The following specific examples and comparative examples will be described. Comparative Example The plastic granules of PVC/PE were uniformly mixed in the weight ratio of the surface, and supplied to the squeaking solution as shown in Fig. 2a. - The cracking temperature of the fine Cao Guan is ·. c, the temperature of the second cracking tank is 350 C, and the remaining cracking and plasticizing steps and conditions are as described above. It should be noted that the second fissile forest of the astringent example contains _ and the absorption example uniformly mixes the weight ratio of the plastic granules of PVC/PE, and supplies it in batches to the lysis apparatus as shown in Fig. 2a. _ undergo thermal cracking 'first-cracking. The cracking temperature of the unblocking tank 201 is 48 〇〇c, and the temperature of the bismuth cracking tank 2〇3 is 350 QC, and the steps and conditions for the remaining cracked plastics are as described above. The first cracking tank 203 contains a catalyst and an absorbent, the catalyst is Fe〇 (〇H), and the absorbent is CaC03 and Ca(OH)2. The density, average carbon number, major carbon number distribution and chlorine content of the obtained oily product after the thermal cracking step of the above examples and comparative examples are shown in Table 2. Table 2 \ PVC/PE (wt%) Catalyst y Absorbent Density (g^cm3) Average Carbon Number Main Carbon Number Distribution Chlorine Content (ppm) Comparative Example 1/100 None 0.77 14.1 n-C8 ~n-C10, 286.71 n-C16-n-C18 Example 1/100 has 0.74 10.7 n-C6-n-C8. 9.26 ηΌ8 〜n-C10 It can be seen from Table 2 that the plastic granules of the examples pass through the catalyst and absorbent 0718- A21362TWF (N2); P10940035TW; Shine 1305787's plastic cracker, 'average carbon number reduction, chlorine content is also obvious, oil quality improvement' is more suitable for fuel or chemical raw materials. On the other hand, 丄 shows that recycling and recycling can extend the life cycle of carbon in plastics, and the impact of carbon dioxide greenhouse effect. In addition, the reduction of gas composition = the lightness of the environment and the sorrow of the sorrow, while avoiding the secondary pollution caused by the incineration of waste plastics. In addition, the use of catalyst and suction (4) helps to reduce cracking time and thus reduce energy consumption. …,of

While the present invention has been described above in terms of the preferred embodiments thereof, it is not intended to limit the invention, and the present invention may be modified and retouched without departing from the spirit and scope of the invention. The scope of protection is subject to the definition of the scope of the patent application.

0718-A21362TWF(N2); P10940035TW;shine 16 1305787 [Simple description of the drawing] Figure 1 shows a conventional plastic cracking device. 2a and 2b are a plastic cracking device according to an embodiment of the present invention. [Main component symbol description] 100, 200a, 200b~ plastic cracking device; 101~ cracking tank; 105, 205~ condenser; 111, 211~ Feed supply tank; 113~nitrogen supply tank; 116, 215, 217, 217a, 217ΐ>~ pipeline; 121, 123, 219, 221, 223~ valve; 201~ first cracking tank; 203~ second cracking tank; 213~ inert gas supply tank; 225~ absorption tank. 0718-A21362TWF(N2);P10940035TW;shine 17

Claims (1)

Announcement 1305787 X. Patent application scope: 1. A plastic cracking device comprising: a first cracking tank for melt cracking a halogen-containing plastic to form a mixture comprising a 'hydrogen halide and a halogenated hydrocarbon: a second cracking tank connected to the first cracking tank for containing FeO(OH) and CaC〇3, wherein FeO(OH) acts as a catalyst for decomposing the halogenated hydrocarbon to form a halogen-free hydrocarbon and a halogen component, CaC03 as a first absorbent for absorbing the hydrogen halide and the halogen component; and a condenser connected to the second cracking tank. 2. The plastic cracking apparatus of claim 1, wherein the second cracking tank is further adapted to contain Ca(0H)2 as a second absorbent. 3. The plastic cracking device according to claim 1, wherein the halogen-containing plastic is a chlorine-containing plastic, the hydrogen halide is hydrogen chloride, the hydrocarbon is a chlorinated hydrocarbon, and the dentate hydrocarbon is chlorine-free. Hydrocarbon, the halogen component is a chlorine component. 4. The plastic cracking device of claim 1, further comprising an absorption tank disposed between the second cracking tank and the condenser. 5. The plastic cracking apparatus of claim 1, further comprising an inert gas supply tank connected to the first cracking tank for supplying nitrogen, helium or neon. 6. A method of cracking a plastic comprising: (a) providing a halogen-containing plastic; (b) cracking the halogen-containing plastic between 300-550 GC to form a mixture 0718-A21362TWF(N2); P10940035TW; a 1305787 compound comprising a hydrogen halide and a dentate hydrocarbon; (C) forming a halogen-free hydrocarbon and a dentate component by decomposing the halogenated hydrocarbon by Fe0(0H) at 33 (M200C; The toothed wind and the dentate component are absorbed between 330-4200C by CaC〇3 and/or Ca(〇JH)2; (4) the mixture is converted to a gaseous state after passing steps (c) and (d) a mixture of the first oil; and (f) condensing the gaseous mixture to obtain a second oil. 7. The method for cracking a plastic according to the method of claim 6 The content is less than 1 〇. The second method is: === _ glue method, 9. If the patent application scope is 6th, the halogen-containing plastic is a chlorine-containing plastic, which is a chlorinated hydrocarbon, and the dentate hydrocarbon is divided into 0 items. The method for cracking a plastic, wherein the hydrogen halide is hydrogen chloride, the toothed hydrocarbon is a chlorine-free hydrocarbon, and the halogen component is a method for cracking a plastic according to item 6 of the chlorine composition, wherein the halogen-containing plastic is Granular or fragmented. /, η. as described in the sixth paragraph of the patent application scope) is to cleave the inclusion between the "c" The step (8) as described in claim 6 of the patent application is further included in the case of containing a gas; 2 plastic. The method of dissolving the halogen as described in claim 6 of the patent application, 〇718-A21362TWF(N2); P1 〇94〇〇35TW; Shine 19^05,787, step (c) is to decompose the halogenated hydrocarbon at 350-380o C. 14. Cracked plastic as described in claim 6 The method of the present invention, wherein the step (d) is to absorb the hydrogen halide and the component of the bismuth at 35 〇 _ 38 〇〇 c. The method for cracking a plastic according to claim 6 of the invention, wherein the first oil The second oil is used as a chemical raw material or a fuel. The method for cracking plastic according to item 6 of the patent scope of the invention, the dentin content of the lower oil of the second oil is higher than that of the first oil. The method of cracking the plastic in the product is 17', as in the method of cracking the plastic according to item 6 of Zhongqing Patent (4), more suitable for the first oil and the second oil, and the mixed tooth in the oil contains 1 It is 0.5 Wt% or less. 0718-A21362TWF(N2) ;P10940035TW;shine 20