CN116083117A

CN116083117A - Catalytic conversion method for simultaneously dechlorinating and desilicating waste plastic oil

Info

Publication number: CN116083117A
Application number: CN202111308747.XA
Authority: CN
Inventors: 宋宝梅; 魏晓丽; 刘宪龙; 张执刚
Original assignee: Sinopec Research Institute of Petroleum Processing; China Petroleum and Chemical Corp
Current assignee: Sinopec Research Institute of Petroleum Processing; China Petroleum and Chemical Corp
Priority date: 2021-11-05
Filing date: 2021-11-05
Publication date: 2023-05-09
Anticipated expiration: 2041-11-05
Also published as: CN116083117B

Abstract

The present disclosure relates to a catalytic conversion method for simultaneously dechlorinating and desilicating waste plastic oil, which comprises: the method comprises the steps of feeding preheated waste plastic oil and steam into the middle lower part of a fluidized bed reactor, sequentially contacting with a catalyst fed from the bottom of the fluidized bed reactor and a dechlorinating agent fed from the middle of the fluidized bed reactor, and carrying out catalytic conversion reaction and dechlorination reaction to obtain reaction oil gas and a spent catalyst; separating the reaction oil and gas to obtain plastic generated oil; introducing the catalyst to be regenerated into a regenerator for burning regeneration to obtain a regenerant, and returning the regenerant to the bottom of the fluidized bed reactor; wherein the catalyst comprises a binder and a low-activity substance, and the mass ratio of the binder to the low-activity substance is 1: (0.05-0.5); the binder is silica sol and/or aluminum sol; the low-active substances are montmorillonite group substances and/or kaolin group substances. The chlorine-containing plastic oil is processed by the method, the yield of the obtained plastic oil is high, the chlorine and silicon contents are low, and the plastic oil is favorable for deep processing and utilization.

Description

Catalytic conversion method for simultaneously dechlorinating and desilicating waste plastic oil

Technical Field

The application relates to the field of recycling of waste plastic oil, in particular to a catalytic conversion method for simultaneously dechlorinating and desilicating waste plastic oil.

Background

With the improvement of environmental awareness and the continuous increase of environmental pressure, the main treatment methods of plastics at present are three modes of landfill, incineration and recycling. The landfill mode is difficult to effectively realize reduction and harmlessness in a short period because the plastic products have low bulk density and are not easy to decompose; the incineration can generate a large amount of greenhouse gases and release harmful gases such as dioxin, and the two modes are gradually eliminated, and the recycling mode becomes the main stream of the mode for treating waste plastics. The recycling mode mainly comprises two modes: the first is physical recovery, after the waste plastics are recovered and granulated, various appliances, articles and the like are manufactured; the second method is to recycle the waste plastics and then catalytically crack the waste plastics to prepare fuel oil products with high added value, and the method has been widely applied in research and production due to higher economic benefit.

At present, most of plastic pyrolysis technology adopts a rotary kiln reactor with an intermittent method, mainly produces oil products, and has an oil product yield of 30% -50%, and the balance of coke and pyrolysis gas. In the production of fuel oil by catalytic pyrolysis of waste plastics, the waste plastics contain about 10% -20% of polyvinyl chloride (PVC) and/or polyvinylidene chloride (PVDC) besides Polyethylene (PE) and polypropylene (PP) as main components, and can be converted into gas products and liquid products through pyrolysis. These liquid products may contain paraffins, isoparaffins, olefins, naphthenes and aromatic components and organic chlorides in concentrations of hundreds of ppm. In addition, the plastic oil is found to contain a certain amount of organic silicon and other impurities through analysis. Therefore, plastic oils cannot be used directly as petrochemicals and require further processing. However, feeds like catalytic cracking and steam cracking processes require very low chlorine content and impurity content requirements to avoid corrosion of the equipment, and thus plastic oils may not be directly used as a feedstock for steam cracking or catalytic cracking (pyrolysis). Therefore, it is necessary to perform a certain pretreatment of the plastic oil before the plastic oil is deeply processed.

Chinese patent document CN201810272820.4 discloses a method for preparing low-chlorine plastic pyrolysis oil, which comprises the following steps: and heating the vinyl chloride-containing mixed plastic stepwise in sections, thoroughly removing the released hydrogen chloride by utilizing nitrogen blowing or vacuum pumping in the temperature range of releasing the hydrogen chloride by decomposing the vinyl chloride, and adding a composite catalyst to perform deep dechlorination and catalytic thermal cracking on the residual materials to obtain the low-chlorine-content plastic pyrolysis oil. The invention uses the same reactor to complete dechlorination and cracking reactions of the mixed plastics, and has the advantages of one-kettle reaction and simple equipment; the sectional method ensures that the mixed plastic is fully decomposed, thereby being beneficial to obtaining different decomposition products; the nitrogen/vacuum assist can enable HCl to be blown off rapidly and thoroughly, has little influence on subsequent plastic cracking reaction, and can obtain plastic cracking oil with low chlorine content. The size of the dechlorination cracking composite catalyst is 10-50 meshes, and the active components of the dechlorination cracking composite catalyst comprise 10-25 wt.% of copper oxide, 40-55 wt.% of iron oxide and 20-50 wt.% of calcium oxide. The method can reduce chlorine content in total liquid product (light oil and heavy oil) from 9328 μg/g to 413 μg/g.

Chinese patent document CN201710675497.0 discloses a waste plastic oil refining method, comprising the steps of: mixing the dechlorinating agent with the waste plastic, adding the mixture into a reaction kettle at 350 ℃ together, mixing with solvent oil, and stirring; discharging the mixed materials from the bottom of the reaction kettle; filtering the mixture material through a filter immediately when the mixture material is hot, filtering out solid chloride and residual solid dechlorinating agent, and pumping a mixture formed by molten polyethylene, molten polypropylene and molten hydrocarbon compound into a next reaction kettle for catalytic cracking reaction. The dechlorinating agent is metal oxide, metal weak acid salt or alkaline metal complex. The method can reduce the chlorine content in the plastic oil to below 0.1%.

Chinese patent document CN201110151747.3 discloses a method and a device for efficiently recycling chlorine-containing plastic waste. The method comprises the steps of coupling two processes of preparing fuel oil by cracking chlorine-containing plastic waste and converting high added value of cracking to generate HCl, so that the aim of recycling chlorine-containing waste is fulfilled, HCl of the chlorine-containing plastic waste is heated and removed in a cracking fluidized bed and further subjected to heating thermal cracking, capturing and catalytic conversion of HCl into chlorine are performed in an integral catalyst fixed bed, the integral catalyst is regenerated while the HCl is converted into chlorine, and catalytically modifying thermally cracked oil gas through a catalytic tower to obtain fuel oil without chlorine.

Chinese patent document CN201210469849.4 provides a method for preparing clean diesel oil by hydrogenation of plastic oil, comprising the steps of: a. mixing the plastic oil and hydrogen, and entering a pre-hydrogenation reactor filled with a hydrogenation protecting catalyst for chemical reaction; b. the effluent of the pre-hydrogenation reactor enters a hot high-pressure separator for separation and gas stripping, and the effluent at the bottom of the hot high-pressure separator and the gas at the top of the cold high-pressure separator enter a main hydrogenation reactor for chemical reaction; c. the effluent of the main hydrogenation reactor enters a cold high-pressure separator for gas-liquid separation, and the effluent at the bottom of the cold high-pressure separator (9) enters a cold low-pressure separator for mixing with light oil extracted from the middle part of the cold high-pressure separator (4) and then enters a fractionating tower for separation. The chlorine content of the liquid product obtained by the method is lower than 0.1ppm.

From the prior art, two methods for producing low-chlorine plastic oil are mainly adopted, one method is to carry out cracking and dechlorination reactions in the plastic cracking process, and the purging method is high in energy consumption and cannot solve the problem of corrosion of hydrogen chloride to equipment. And the other is to carry out post-treatment dechlorination on chlorine-containing plastic oil, the hydrogenation technology of the route is mainly adopted, the process flow is complex due to hydrogen consumption, the requirement on equipment materials is high, and the investment cost is greatly increased. The prior art has not been reported on the plastic oil desilication technology, so that the development of the low-cost plastic oil desilication technology is favorable for deep processing of plastic oil, realizes high value and brings higher social benefit and economic benefit.

Disclosure of Invention

The present disclosure aims to provide a method for simultaneously dechlorinating and desilicating chlorine-containing plastic oil.

In order to achieve the above object, the present disclosure provides a catalytic conversion method for simultaneously dechlorinating and desilicating waste plastic oil, the method comprising:

s1, feeding preheated waste plastic oil and steam into the middle lower part of a fluidized bed reactor, sequentially contacting with a catalyst fed from the bottom of the fluidized bed reactor and a dechlorinating agent fed from the middle of the fluidized bed reactor, and carrying out catalytic conversion reaction and dechlorination reaction to obtain reaction oil gas and a spent catalyst;

s2, separating the reaction oil and gas to obtain plastic generated oil;

s3, introducing the spent catalyst into a regenerator for burning regeneration to obtain a regenerated catalyst, and returning the regenerated catalyst to the bottom of the fluidized bed reactor;

wherein the catalyst comprises a binder and a low-activity substance, and the mass ratio of the binder to the low-activity substance is 1: (0.05-0.5); the binder is silica sol and/or alumina sol; the low-activity substance is montmorillonite and/or kaolin.

Optionally, the waste plastic oil is selected from at least one of polyethylene, polypropylene, polystyrene, polyvinyl chloride, polyvinylidene chloride and polyethylene terephthalate; preferably, the properties of the waste plastic oil meet at least one of the following criteria: the density of the waste plastic oil at 20 ℃ is 750-900kg/m ³ The carbon residue content of the waste plastic oil is 0-2 wt%, the silicon content of the waste plastic oil is 50-2000mg/kg, and the chlorine content of the waste plastic oil is 50-5000mg/kg.

Optionally, the conditions of the catalytic conversion reaction include: the reaction temperature is 380-550 ℃, preferably 400-450 ℃; the reaction time is 0.1 to 5 seconds, preferably 1 to 3 seconds; the weight ratio of the agent to the oil is (5-100): 1, preferably (10-30): 1, a step of; the weight ratio of water to oil is (0.05-0.5): 1, preferably (0.1-0.3): 1.

optionally, the catalyst further comprises alumina; alternatively, the alumina content is 0.05 to 50 wt%, preferably 10 to 30 wt%, based on the total weight of the catalyst; the binder content is 50-99.5 wt%, preferably 50-90 wt%; the content of the low-active substance is 0.05 to 50% by weight, preferably 10 to 30% by weight.

Optionally, the preparation method of the catalyst comprises the following steps: mixing the binder and the low-activity substances to obtain a mixed material, and carrying out spray drying and roasting on the mixed material; optionally, the firing temperature is 630-750 ℃.

Optionally, the dechlorinating agent contains a calcium compound, an inorganic oxide, and clay; the dechlorinating agent comprises 5-80 wt% of calcium compound, 5-95 wt% of inorganic oxide and 0-50 wt% of clay on a dry basis and based on the total weight of the dechlorinating agent; the calcium compound is at least one of calcium hydroxide, calcium carbonate and calcium oxide; the inorganic oxide is silicon dioxide and/or aluminum oxide; the clay is kaolin and/or halloysite.

Alternatively, the dechlorinating agent is used in an amount of 200-10000mg/kg, preferably 200-10000mg/kg, based on the total weight of the waste plastic oil feed amount.

Optionally, the location of introduction of the dechlorinating agent into the fluidized bed reactor is located 1/3-3/4 from the bottom of the fluidized bed reactor; preferably, the location of introduction of the dechlorinating agent into the fluidised bed reactor is located 1/2 to 2/3 of the distance from the bottom of the fluidised bed reactor.

Optionally, the conditions for the char regeneration include: the temperature is 600-700 ℃ and the pressure is 1.0-2.5MPa; preferably, the temperature is 630-680 ℃ and the pressure is 1.0-2.0MPa.

Optionally, the fluidized bed reactor is selected from one of a fixed fluidized bed, a bulk fluidized bed, a bubbling bed, a turbulent bed, a fast bed, a riser reactor, and a dense-phase fluidized bed; the riser is selected from one of an equal diameter riser, an equal linear velocity riser and a variable diameter riser, preferably an equal diameter riser.

Through above-mentioned technical scheme, this disclosure has following beneficial effect:

(1) After the waste plastic oil is contacted with the catalyst, the chlorine compound of the plastic oil can be effectively adsorbed on the surface of the catalyst, so that the decomposition reaction of carbon-chlorine bonds occurs to generate hydrogen chloride, and the generated hydrogen chloride is converted into chloride by introducing a dechlorinating agent in the reaction process, so that the chlorine content in the plastic oil is reduced, and the corrosion of the hydrogen chloride to equipment is also reduced.

(2) In the contact reaction process of the chlorine-containing waste plastic oil and the catalyst, the silicon compound in the waste plastic oil is subjected to decomposition reaction simultaneously, and silicon is deposited on the catalyst, so that the aim of desilication is fulfilled.

(3) The method disclosed by the invention solves the problems of equipment corrosion and catalyst performance influence caused by impurities such as chlorine and silicon, improves the quality of the chlorine-containing waste plastic oil, has high yield of the obtained high-quality plastic oil, has low chlorine and silicon content, and is favorable for deep processing and utilization of the plastic oil.

Additional features and advantages of the present disclosure will be set forth in the detailed description which follows.

Drawings

The accompanying drawings are included to provide a further understanding of the disclosure, and are incorporated in and constitute a part of this specification, illustrate the disclosure and together with the description serve to explain, but do not limit the disclosure. In the drawings:

fig. 1 is a flow diagram of one embodiment of the present disclosure.

Description of the reference numerals

1. Fluidized bed reactor 2 and settler

3. Regenerator 4, steam line

5. Waste plastic oil feed line 6, pre-lift gas line

7. Regeneration inclined tube 8, cyclone separator

9. Stripping section 10, waiting inclined tube

11. Gas collection chamber 12, large oil gas pipeline

13. Flue gas pipeline 14 and dechlorinating agent pipeline

15. Stripping steam line 16, fractionation column

17. Gas line 18, plastic production line

Detailed Description

The following describes specific embodiments of the present disclosure in detail. It should be understood that the detailed description and specific examples, while indicating and illustrating the disclosure, are not intended to limit the disclosure.

The present disclosure provides a catalytic conversion method for simultaneously dechlorinating and desilicating waste plastic oil, the method comprising:

s2, separating the reaction oil and gas to obtain plastic generated oil;

After the waste plastic oil is contacted with the catalyst, the chlorine compounds of the plastic oil can be effectively adsorbed on the surface of the catalyst, so that the decomposition reaction of carbon-chlorine bonds occurs to generate hydrogen chloride, and the generated hydrogen chloride is converted into chloride by introducing a dechlorinating agent in the reaction process, so that the chlorine content in the plastic oil is reduced, and the corrosion of the hydrogen chloride to equipment is also reduced. In the contact reaction process of the chlorine-containing waste plastic oil and the catalyst, the silicon compound in the waste plastic oil is subjected to decomposition reaction simultaneously, and silicon is deposited on the catalyst, so that the aim of desilication is fulfilled.

The method of the present disclosure may further comprise: and (3) separating the reaction oil and gas to obtain plastic generated oil and gas, and returning the gas to the bottom of the fluidized bed reactor to serve as pre-lifting gas.

The separation of the reaction oil and gas from the spent catalyst in this disclosure is well known to those skilled in the art, and for example, may be performed in a settler using a cyclone separator, and the process of further separating the reaction oil and gas to obtain gas and low chlorine low silicon plastic oil is also well known to those skilled in the art.

Both the oil separation apparatus and the reaction oil and gas separation apparatus described in this disclosure are well known to those skilled in the art, and for example, the oil separation apparatus may include a cyclone, a settler, a stripper, and the like, and the reaction oil and gas separation apparatus may be a fractionation column, and the like.

According to the present disclosure, the waste plastic oil may be selected from at least one of polyethylene, polypropylene, polystyrene, polyvinyl chloride, polyvinylidene chloride, and polyethylene terephthalate; preferably, the property of the waste plastic oil may satisfy at least one of the following indexes: the density of the waste plastic oil at 20 ℃ is 750-900kg/m ³ The carbon residue content of the waste plastic oil is 0-2 wt%, the silicon content of the waste plastic oil is 50-2000mg/kg, and the chlorine content of the waste plastic oil is 50-5000mg/kg.

According to the present disclosure, the conditions of the catalytic conversion reaction may include: the reaction temperature is 380-550 ℃, preferably 400-450 ℃; the reaction time is 0.1 to 5 seconds, preferably 0.1 to 3 seconds; the weight ratio of the agent to the oil is (5-100): 1, preferably (10-30): 1, a step of; the weight ratio of water to oil is (0.05-0.5): 1, preferably (0.1-0.3): 1. the inventor of the present disclosure finds through a great deal of experiments that the low-activity catalyst has a plurality of weak acid centers, in the present disclosure, a large amount of oil ratio is adopted to provide more suitable acid centers for the decomposition reaction of the chlorine compounds in the waste plastic oil, so that the hydrocarbon molecules in the plastic oil can be avoided from being decomposed while the sufficient decomposition of the chlorine compounds is ensured, and the yield of the low-chlorine low-silicon plastic oil is improved.

According to the present disclosure, the catalyst may further comprise alumina; alternatively, the alumina content is 0.05 to 50 wt%, preferably 10 to 30 wt%, based on the total weight of the catalyst; the binder content is 50-99.5 wt%, preferably 50-90 wt%; the content of the low-active substance is 0.05 to 50% by weight, preferably 10 to 30% by weight.

According to the present disclosure, the method of preparing the catalyst may include: mixing the binder and the low-activity substances to obtain a mixed material, and carrying out spray drying and roasting on the mixed material; optionally, the firing temperature is 630-750 ℃.

According to the present disclosure, the dechlorinating agent may contain a calcium compound, an inorganic oxide, and clay; the dechlorinating agent may comprise 5-80 wt% calcium compound, 5-95 wt% inorganic oxide and 0-50 wt% clay on a dry basis and based on the total weight of the dechlorinating agent; the calcium compound may be at least one of calcium hydroxide, calcium carbonate, and calcium oxide; the inorganic oxide may be silica and/or alumina; the clay is kaolin and/or halloysite.

According to the present disclosure, the dechlorinating agent may be used in an amount of 200-10000mg/kg, preferably 200-10000mg/kg, based on the total weight of the waste plastic oil feed amount.

According to the present disclosure, the location of introduction of the dechlorinating agent into the fluidized bed reactor may be located 1/3-3/4 from the bottom of the fluidized bed reactor; preferably, the location of introduction of the dechlorinating agent into the fluidised bed reactor may be located 1/2 to 2/3 of the distance from the bottom of the fluidised bed reactor.

The manner of regenerating the spent catalyst by burning is well known to those skilled in the art in light of the present disclosure, and may be performed in a regenerator, an oxygen-containing gas such as air may be introduced into the regenerator to contact the spent catalyst, and flue gas obtained by burning and regenerating may be sent to a subsequent energy recovery system after being separated from the catalyst in the regenerator. The conditions for the char regeneration may include: the temperature is 600-700 ℃ and the pressure is 1.0-2.5MPa; preferably, the temperature is 630-680 ℃ and the pressure is 1.0-2.0MPa.

According to the present disclosure, the fluidized bed reactor may be selected from one of a fixed fluidized bed, a bulk fluidized bed, a bubbling bed, a turbulent bed, a fast bed, a riser reactor, and a dense-phase fluidized bed; the riser is selected from one of an equal diameter riser, an equal linear velocity riser and a variable diameter riser, preferably an equal diameter riser.

In a specific embodiment of the present disclosure, as shown in fig. 1, a pre-lifting medium enters from the bottom of the fluidized bed reactor 1 through a pre-lifting gas line 6, a regenerated catalyst from a regeneration inclined tube 7 enters into the fluidized bed reactor 1, and moves upward along the fluidized bed reactor under the lifting action of the pre-lifting medium in an accelerating manner, chlorine-containing waste plastic oil is mixed with steam from a steam line 4 through a waste plastic oil feeding line 5 and then injected into the fluidized bed reactor 1 to be mixed with the existing material flow of the fluidized bed reactor, and the waste plastic oil undergoes a catalytic cracking reaction on a hot catalyst and moves upward in an accelerating manner. Dechlorination agent is injected into the fluidized bed reactor 1 through a dechlorination agent line 14, is mixed and reacted with a stream from the fluidized bed reactor, and is moved upward with acceleration. The generated reaction product and the deactivated spent catalyst enter a cyclone separator 8 in a settler 2 to realize the separation of the spent catalyst and the reaction product, the reaction product enters a gas collection chamber 11, and the catalyst fine powder returns to the settler. The spent catalyst in the settler flows to the stripping section 9 where it is stripped in contact with steam from stripping steam line 15. The reaction product stripped from the spent catalyst enters a gas collection chamber 11 after passing through a cyclone separator, then enters a fractionating tower 16 through a large oil gas pipeline 12 to be separated into gas and low-chlorine low-silicon plastic generated oil, the stripped spent catalyst enters a regenerator 3 through a spent inclined tube 10, coke on the spent catalyst is burned off, the deactivated spent catalyst is regenerated, and the flue gas enters a subsequent energy recovery system through a flue gas pipeline 13. The dry gas is used as part or all of the pre-lifting medium for the catalytic conversion reaction. The regenerated catalyst after regeneration is circulated to the bottom of the fluidized bed reactor 1 through a regeneration inclined pipe 7.

The present disclosure is further illustrated in detail by the following examples. The starting materials used in the examples are all available commercially.

The raw materials used in the examples and comparative examples were waste plastic oil mixtures, and the properties are shown in Table 1.

The catalyst used in the comparative example was an aging agent for the catalyst of conventional catalytic cracking, while the catalyst used in example 1 was catalyst a, and the catalyst used in example 2 was catalyst B, the properties of which are shown in table 2.

Wherein, the catalyst A is prepared by spray drying a mixture formed by a binder (silica sol) and kaolin according to the weight ratio of 5:95 and then roasting at 700 ℃; catalyst B was prepared from binder (silica sol), kaolin and alumina oxygen according to 5:90:5, and roasting at 700 ℃ after spray drying.

TABLE 1

Project	Waste plastic oil
		Density in kg/cubic meter	801.9
Sulfur content, micrograms/gram	246
		Carbon residue,% (by weight)	0.24
Nitrogen content, micrograms/gram	700
		Metal content, micrograms/gram
Iron (Fe)	2.0
		Nickel (Ni)	<0.1
Vanadium (V)	<0.1
		Sodium salt	0.2
Calcium	<0.1
		Silicon, micrograms/gram	705
Chlorine content, micrograms/gram	2350

TABLE 2

Project	Catalyst A	Catalyst B	Aging agent
				Physical Properties
Specific surface area (meter) ² /g)	23	27	129
				Specific surface area of molecular sieve (rice) ² /g)	/	/	74
Pore volume (cm) ³ /g)	0.00217	0.00937	0.176
				Sieving composition, weight percent
0～40μm	4.0	8.2	12.7
				40～80μm	41.8	54.3	41.7
80～110μm	23.1	21.1	24.9
				Average particle diameter/. Mu.m	68.9	83.4	75.4
Micro-inverse Activity,%	18	23	65

The dechlorinating agent used in the examples was prepared as follows:

pulping the multi-water kaolin by using deionized water, adding pseudo-boehmite, regulating the PH of the multi-water kaolin to 2-4 by using hydrochloric acid, uniformly stirring, standing and aging for 1 hour at 60-70 ℃, keeping the PH to 2-4, cooling to below 60 ℃, adding aluminum sol, and stirring for 40 minutes to obtain mixed slurry. And adding the calcium compound into the obtained mixed slurry, uniformly stirring, spray-drying, forming and drying to obtain the dechlorination agent sample.

Example 1

The test was carried out according to the procedure of fig. 1, and the waste plastic oil catalytic conversion reaction test was carried out on a medium-sized apparatus of a riser reactor, wherein the raw oil was a waste plastic oil mixture, and the catalyst was catalyst a.

The preheated waste plastic oil and steam enter the middle lower part of the riser reactor to be contacted with a hot catalyst fed from the bottom of the fluidized bed reactor and carry out catalytic conversion reaction, dechlorination agent is injected into the downstream of the riser reactor, the dosage of the dechlorination agent is 2000mg/kg based on the total weight of the feeding amount of the waste plastic oil, and the dechlorination reaction is carried out with hydrogen chloride generated by the catalytic conversion reaction in the riser reactor to obtain reaction oil gas and spent catalyst; the reaction oil gas and the spent catalyst enter a closed cyclone separator from the outlet of a riser reactor, so that the reaction oil gas and the spent catalyst are rapidly separated, and the reaction oil gas is separated into gas and plastic produced oil with low chlorine and low silicon in a separation system according to a distillation range. The separated gas is returned to the bottom of the riser reactor for use as pre-lift gas.

The spent catalyst enters a stripping section under the action of gravity, hydrocarbon products adsorbed on the spent catalyst are stripped by steam, and the stripped spent catalyst enters a regenerator to be in contact with air for regeneration; the regenerated catalyst is returned to the riser reactor for recycling. The operating conditions and product distribution are listed in Table 3.

As can be seen from the results in Table 3, the low-chlorine low-silicon plastic oil of example 1 had a yield of 98.36% or more, a chlorine content of 9.0 mg/kg and a silicon content of 8.5 mg/kg, and both the dechlorination rate and the desilication rate were 99% or more.

Example 2

Example 2 differs from example 1 in that catalyst a is replaced by catalyst B.

As can be seen from the results in Table 3, the low-chlorine low-silicon plastic oil of example 2 has a yield of 97.73% or more, a chlorine content of 6.7 mg/kg, a silicon content of 5.4 mg/kg, and a dechlorination rate and a desilication rate of 99% or more.

Comparative example 1

According to the test carried out on a medium-sized device of a riser according to FIG. 1, raw oil is a waste plastic oil mixture, a catalytic conversion catalyst is an ageing agent of a conventional catalytic cracking catalyst, the waste plastic oil mixture enters a riser reactor, contacts with a hot catalyst and carries out catalytic conversion reaction, reaction oil gas and spent catalyst enter a closed cyclone separator from an outlet of the reactor, the reaction oil gas and the spent catalyst are rapidly separated, and products such as gas, plastic oil and the like are separated according to distillation ranges in a separation system. Part of the gas is returned to the bottom of the riser reactor for use as pre-lift gas.

The spent catalyst enters a stripping section under the action of gravity, hydrocarbon products adsorbed on the spent catalyst are stripped by steam, and the stripped spent catalyst enters a regenerator to be in contact with air for regeneration; the regenerated catalyst is returned to the riser reactor for recycling; the operating conditions and product distribution are listed in Table 3. As can be seen from the results in Table 3, the yield of the low-chlorine low-silicon plastic oil was 81.1%, the chlorine content in the plastic oil was 180.0 mg/kg, and the silicon content was 93.0 mg/kg.

TABLE 3 Table 3

As can be seen from the data in table 3: compared with example 1, example 2 is applicable to catalyst B containing activated alumina, and the content of silicon and chlorine in the liquid product is lower, so that the method disclosed by the invention greatly reduces the chlorine content and the silicon content in the waste plastic oil and plastic oil, and has high plastic oil yield and small loss.

The preferred embodiments of the present disclosure have been described in detail above, but the present disclosure is not limited to the specific details of the above embodiments, and various simple modifications may be made to the technical solutions of the present disclosure within the scope of the technical concept of the present disclosure, and all the simple modifications belong to the protection scope of the present disclosure.

In addition, the specific features described in the above embodiments may be combined in any suitable manner without contradiction. The various possible combinations are not described further in this disclosure in order to avoid unnecessary repetition.

Moreover, any combination between the various embodiments of the present disclosure is possible as long as it does not depart from the spirit of the present disclosure, which should also be construed as the disclosure of the present disclosure.

Claims

1. A catalytic conversion process for simultaneously dechlorinating and desilicating waste plastic oil, the process comprising:

s2, separating the reaction oil and gas to obtain plastic generated oil;

2. The catalytic conversion process according to claim 1, wherein,

the waste plastic oil is at least one selected from polyethylene, polypropylene, polystyrene, polyvinyl chloride, polyvinylidene chloride and polyethylene terephthalate;

preferably, the properties of the waste plastic oil meet at least one of the following criteria: the density of the waste plastic oil at 20 ℃ is 750-900kg/m ³ The carbon residue content of the waste plastic oil is 0-2 wt%, the silicon content of the waste plastic oil is 50-2000mg/kg, and the chlorine content of the waste plastic oil is 50-5000mg/kg.

3. The catalytic conversion process according to claim 1, wherein,

the conditions of the catalytic conversion reaction include: the reaction temperature is 380-550 ℃, preferably 400-450 ℃; the reaction time is 0.1 to 5 seconds, preferably 0.1 to 3 seconds; the weight ratio of the agent to the oil is (5-100): 1, preferably (10-30): 1, a step of; the weight ratio of water to oil is (0.05-0.5): 1, preferably (0.1-0.3): 1.

4. the catalytic conversion process according to claim 1, wherein,

the catalyst further comprises alumina;

alternatively, the alumina content is 0.05 to 50 wt%, preferably 10 to 30 wt%, based on the total weight of the catalyst; the binder content is 50-99.5 wt%, preferably 50-90 wt%; the content of the low-active substance is 0.05 to 50% by weight, preferably 10 to 30% by weight.

5. The catalytic conversion process according to claim 1, wherein the process for preparing the catalyst comprises: mixing the binder and the low-activity substances to obtain a mixed material, and carrying out spray drying and roasting on the mixed material;

optionally, the firing temperature is 630-750 ℃.

6. The catalytic conversion process according to claim 1, wherein the dechlorinating agent contains a calcium compound, an inorganic oxide, and clay;

the dechlorinating agent comprises 5-80 wt% of calcium compound, 5-95 wt% of inorganic oxide and 0-50 wt% of clay on a dry basis and based on the total weight of the dechlorinating agent;

the calcium compound is at least one of calcium hydroxide, calcium carbonate and calcium oxide;

the inorganic oxide is silicon dioxide and/or aluminum oxide;

the clay is kaolin and/or halloysite.

7. The catalytic conversion process according to claim 1, wherein the dechlorinating agent is used in an amount of 200-10000mg/kg, preferably 200-10000mg/kg, based on the total weight of the waste plastic oil feed amount.

8. The catalytic conversion process of claim 1, wherein the dechlorination agent is introduced into the fluidized bed reactor at a location 1/3-3/4 from the bottom of the fluidized bed reactor; preferably, the location of introduction of the dechlorinating agent into the fluidised bed reactor is located 1/2 to 2/3 of the distance from the bottom of the fluidised bed reactor.

9. The catalytic conversion process of claim 1, wherein the conditions of char regeneration comprise: the temperature is 600-700 ℃ and the pressure is 1.0-2.5MPa; preferably, the temperature is 630-680 ℃ and the pressure is 1.0-2.0MPa.

10. The catalytic conversion process of claim 1, wherein the fluidized bed reactor is selected from one of a fixed fluidized bed, a bulk fluidized bed, a bubbling bed, a turbulent bed, a fast bed, a riser reactor, and a dense-phase fluidized bed; the riser is selected from one of an equal diameter riser, an equal linear velocity riser and a variable diameter riser, preferably an equal diameter riser.