Hydrodechlorination and desiliconization method for waste plastic oil

Abstract

The invention discloses a method for hydrodechlorination and desiliconization of waste plastic oil, which comprises the following steps: removing Cl and Si elements from the waste plastic oil by using a slurry reactor under the action of a hydrogenation catalyst and hydrogen to finally obtain Cllt; 0.2 [mu] g / g, Silt; 1 [mu] g / g of a waste plastic oil product; the hydrogenation catalyst is a compound catalyst formed by an oil-soluble catalyst and a powder catalyst subjected to alkali treatment, and after recycling, the inactivated catalyst is subjected to roasting, primary alkali treatment, secondary alkali treatment and grinding and then regenerated to obtain the powder catalyst; therefore, the problems that in the removal process of Si and Cl elements in the waste plastic oil, catalytic materials, devices and equipment and product properties are affected, and hydrodechlorination and desiliconization catalysts are difficult to regenerate are solved.

Description

Technical Field

[0001] The invention relates to the technical field of waste oil treatment, in particular to a method for hydrogenating, dechlorinating and desiliconizing waste plastic oil. Background Art

[0002] Between 1950 and 2015, the world produced a total of about 8.3 billion tons of waste plastics, of which about 79% were landfilled or directly discharged, causing serious damage to the environment. By 2019, about 32% of my country's waste plastics were landfilled and about 31% were incinerated, causing serious pollution to the soil and atmospheric environment. The high-value recycling of waste plastics has become a hot topic in recent years. Waste plastic oil technology is an important chemical recycling technology for converting waste plastics into higher-value products. However, due to the presence of a certain amount of Cl and Si elements in waste plastics, and part of them will be transferred to waste plastic oil during the process of waste plastic oil, it has a great impact on the catalytic materials, equipment and product properties in the process of waste plastic oil processing and quality improvement, such as catalyst poisoning and deactivation, equipment corrosion, etc. Therefore, how to effectively remove Cl and Si impurities in waste plastic oil is one of the key issues facing the industrial recycling of waste plastics.

[0003] Hydrogenation of oil products is an important means of deep impurity removal and quality improvement. The deep dechlorination / siliconization of waste plastic oil by hydrogenation reaction process has good application prospects. However, in the current hydrodechlorination and desiliconization process, Cl and Si elements are prone to deactivation and clogging of hydrogenation catalysts and are not easy to regenerate, affecting the problem of equipment operation cycle. For example, Chinese patent document CN111171865A discloses a dechlorination method for waste plastic pyrolysis oil, which reacts the waste plastic pyrolysis oil with hydrogen under the action of a hydrogenation catalyst, and then mixes the product oil obtained by hydrogenation with an adsorbent, and performs adsorption treatment to obtain oil products after adsorption and dechlorination. Chinese patent document CN114437764A discloses a desiliconization method and system for silicon-containing hydrocarbon raw materials, which enters a hydrogenation reactor in the presence of hydrogen and contacts with a hydrogenation catalyst, and performs desiliconization reaction under hydrogenation reaction conditions, wherein the hydrogenation reactor is at least one fixed bed hydrogenation reactor and / or at least one moving bed hydrogenation reactor, and the silicon content of the liquid phase material in the reaction effluent is less than 1.0 μg / g. Chinese patent document CN114437763A discloses a method and system for hydrogenation pretreatment of waste plastic oil and / or waste tire oil, wherein waste plastic oil and waste tire oil are placed in a hydrogenation reactor in the presence of hydrogen and contacted with waste hydrogenation catalyst and dechlorinating agent, and desulfurization, desiliconization and demetallization reactions are carried out under hydrogenation reaction conditions. The silicon content of the liquid phase material in the resulting reaction effluent is less than 1 μg / g, the chlorine content is less than 0.5 μg / g, and the metal content is less than 5 μg / g. However, in this scheme, waste hydrogenation catalyst is used for hydrogenation and decontamination operation, and the waste catalyst has limited capacity to tolerate impurities such as chlorine, silicon, and metals, and the catalyst deactivates quickly, affecting the operating cycle of the device.

[0004] To solve the above problems, most of the existing technologies achieve the effect of extending the operation cycle of the device by switching between fixed bed reactors or using moving bed reactors; however, switching between fixed bed reactors will cause device loss and increase device operating costs; the use of moving bed reactors requires a large amount of catalyst, and the structure of moving bed reactors is relatively complex; in addition, the hydrogenation catalyst used in both fixed and moving beds is easily deactivated and difficult to regenerate after removing chlorine and silicon, which also increases the cost of the catalyst. Therefore, how to reduce the cost of the device and catalyst while ensuring the removal of chlorine and silicon in waste plastic oil is a technical problem that needs to be solved urgently. Summary of the invention

[0005] In view of this, the present invention provides a method for hydrogenating, dechlorinating and desiliconizing waste plastic oil. A composite catalyst formed by compounding an oil-soluble catalyst and a powdered catalyst treated with an alkali is used to carry out a hydrogenation reaction in a slurry bed reactor. While enhancing the removal effect of Cl and Si elements, the composite catalyst can be discharged from the slurry bed reactor together with the product, which will not affect the operation of the device, and the discharged catalyst can be recycled into the slurry bed reactor together with the waste plastic oil until it is deactivated. The deactivated hydrogenation catalyst is regenerated by roasting, alkali treatment and grinding to obtain a powdered catalyst. Among them, the oil-soluble catalyst mainly plays the role of increasing the active sites, and the powdered catalyst with a large specific surface area and pore volume can provide a carrier for the attachment of Cl and Si elements, and take them out of the reaction system. The method for hydrogenating, dechlorinating and desiliconizing waste plastic oil provided by the present invention has excellent dechlorination and desiliconization effects, and reduces device loss and cost.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] A method for hydrogenating, dechlorinating and desiliconizing waste plastic oil, comprising the following steps: a hydrogenation catalyst, waste plastic oil and hydrogen flow from bottom to top in a slurry bed reactor to perform dechlorination and desiliconization reactions to obtain a product with Cl < 0.2 μg / g and Si < 1 μg / g;

[0008] Wherein, the hydrogenation catalyst is a composite catalyst formed by an oil-soluble catalyst and a powdered catalyst treated with alkali;

[0009] The carrier of the powder catalyst is silicon oxide.

[0010] Optionally, in the above-mentioned method for hydrodechlorination and desiliconization of waste plastic oil, the alkali treatment process includes:

[0011] The powdered catalyst is immersed in an alkali solution of 0.2-1.0 mol / L at 60-100° C. for 0.5-3 h, and then washed, dried and ground to obtain an alkali-treated powdered catalyst.

[0012] Optionally, in the alkali treatment process of the above-mentioned waste plastic oil hydrodechlorination and desiliconization method, the alkali solution is selected from at least one of ammonia water, sodium hydroxide solution, potassium hydroxide solution, etc.

[0013] Optionally, in the above-mentioned method for hydrodechlorination and desiliconization of waste plastic oil, the active component of the powdered catalyst comprises at least one of Co, Mo and W;

[0014] The oil-soluble catalyst can be any conventional one in the industry. The active component of the oil-soluble catalyst recommended by the present invention is Mo.

[0015] Preferably, in the above-mentioned method for hydrodechlorination and desiliconization of waste plastic oil, based on the mass of the powdered catalyst being 100%, the content of the active component in the powdered catalyst is 5wt%-30wt%.

[0016] Optionally, in the above-mentioned method for hydrodechlorination and desiliconization of waste plastic oil, the specific surface area of ​​the powder catalyst is 320-600m 2 / g, pore volume is 0.6-1cm 3 / g.

[0017] Optionally, in the above-mentioned method for hydrodechlorination and desiliconization of waste plastic oil, the oil-soluble catalyst and the powder-type catalyst are respectively calculated by the mass of the active components, and the mass of the waste plastic oil is 100%, the oil-soluble catalyst is added in an amount of 100-2000ppm, and the powder-type catalyst is added in an amount of 1wt%-10wt%; preferably, the oil-soluble catalyst is added in an amount of 300-1000ppm, and the powder-type catalyst is added in an amount of 3wt%-6wt%.

[0018] Optionally, in the above-mentioned method for hydrogenating and dechlorinating and desiliconizing waste plastic oil, the temperature of the dechlorination and desiliconization reaction is 300-420°C, the pressure is 2-10MPa, and the liquid hourly space velocity is 0.1-0.6h -1 , hydrogen-to-oil ratio is 200-1200;

[0019] Preferably, the temperature of the dechlorination and desiliconization reaction is 360-400°C, the pressure is 4-8MPa, and the liquid hourly space velocity is 0.1-0.4h -1 , the hydrogen-to-oil ratio is 600-1000.

[0020] Optionally, in the above-mentioned method for hydrogenating, dechlorinating and desiliconizing waste plastic oil, when Cl≥0.2μg / g or Si≥1μg / g in the product, it indicates that the hydrogenation catalyst is deactivated, and a fresh hydrogenation catalyst can be replaced to continue the reaction in the slurry bed reactor. The material discharged from the slurry bed reactor is separated by gas, liquid and solid, and the solid obtained is the deactivated hydrogenation catalyst. The deactivated hydrogenation catalyst is sequentially calcined, treated with an alkali once, treated with an alkali twice, washed with deionized water, dried, and ground for regeneration to obtain a regenerated powdered catalyst.

[0021] Optionally, in the above-mentioned method for hydrodechlorination and desiliconization of waste plastic oil, during the regeneration of the deactivated powdered catalyst, the calcination temperature is 450-700° C., preferably 500-600° C., and the calcination time is 2-8 h;

[0022] The alkaline solution used in the first alkaline treatment process is ammonia water; the alkaline solution used in the second alkaline treatment process is at least one of ammonia water, sodium hydroxide solution, and potassium hydroxide solution. The concentration of the specific alkaline solution is not specifically limited. For example, the first alkaline treatment can be immersed in 60-100°C, 0.2-1.0 mol / L ammonia water for 0.5-3 hours, and the second alkaline treatment can be immersed in 60-100°C, 0.2-1.0 mol / L alkaline solution for 0.5-3 hours.

[0023] Compared with the prior art, the present invention has the following advantages:

[0024] Beneficial effect 1: The method for hydrogenating, dechlorinating and desiliconizing waste plastic oil provided by the present invention adopts a slurry bed reactor, and the hydrogenation catalyst can be removed or added online without extending the operation cycle by switching the reactor. In addition, the slurry bed reactor has a simpler structure than the moving bed reactor and uses less catalyst.

[0025] Beneficial effect 2: The method for hydrogenating, dechlorinating and desiliconizing waste plastic oil provided by the present invention uses a composite catalyst formed by an oil-soluble catalyst and a powdered catalyst treated with alkali, which is beneficial to the formation of high-activity sites and the dispersion of active metals. Among them, the powdered catalyst has a relatively large specific surface area and pore volume, providing more reaction space and silicon capacity; the good dispersion effect of the oil-soluble catalyst can provide more active sites and promote the dechlorination and desiliconization effects. Furthermore, by alkali-treating the powdered catalyst in the hydrogenation catalyst, the hydroxyl sites of the hydrogenation catalyst are effectively increased, which can improve the dispersion of the active sites (active components) in the catalyst on the one hand, and improve the dechlorination and desiliconization effects on the other hand.

[0026] Beneficial effect 3: The method for hydrogenating, dechlorinating and desiliconizing waste plastic oil provided by the present invention uses a powder catalyst with a large specific surface area and pore volume that is significantly greater than that of an oil-soluble catalyst, and can provide a carrier for the Cl and Si elements removed from the waste plastic oil to attach to, and bring the Cl and Si elements out of the reaction system, while the Cl and Si elements have little effect on the oil-soluble catalyst. In addition, the powder catalyst carrier is silicon oxide, which weakens the effect of the silicon element in the waste plastic oil. In the later stage, the C and H elements in the silicon-containing compound attached to the powder catalyst are removed by roasting the deactivated powder catalyst; Si is directly left in the powder catalyst, and further treated with an alkali once and a second alkali, on the one hand, the Cl element on the catalyst surface is replaced; on the other hand, the pores, surface properties and hydroxyl sites of the powder catalyst are modified and regenerated, and finally, ground into powder to achieve the regeneration of the catalyst. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 A schematic diagram of a method for hydrogenating, dechlorinating and desiliconizing waste plastic oil provided by the present invention.

[0028] 1. Hydrogen; 2. Chlorine- and silicon-containing waste plastic oil; 3. Slurry bed reactor; 4. Waste plastic oil products. DETAILED DESCRIPTION

[0029] The present invention is described in detail below by way of examples. It is necessary to point out that the following examples are only used to further illustrate the present invention and cannot be understood as limiting the scope of protection of the present invention. Those skilled in the art in this field can make some non-essential improvements and adjustments to the present invention based on the above content of the present invention.

[0030] If no specific experimental steps or conditions are specified in the examples, the conventional experimental steps or conditions described in the literature in the field can be used. If no manufacturer is specified for the reagents or instruments used, they are all conventional reagent products that can be obtained commercially.

[0031] Any waste plastic oil containing Cl and Si can satisfy the implementation of the technical solution of the present invention. However, for the convenience of comparison, waste plastic oils with the following properties are used in the following embodiments and comparative examples.

[0032] Table 1 Properties of waste plastic oil

[0033] parameter Numeric <![CDATA[Density (g / cm 3 )]]> 0.8949 <![CDATA[Viscosity (50 °C) mm 2 / s]]> 9.892 Distillation range(℃) 65～706 Cl(μg / g) 2986.4 SI (μg / g) 362.7

[0034] Existing oil-soluble catalysts can all satisfy the implementation of the technical solution of the present invention; however, for the convenience of comparison, molybdenum isooctanoate is used in the following embodiments and comparative examples.

[0035] Example 1

[0036] This embodiment provides a method for hydrogenating, dechlorinating and desiliconizing waste plastic oil, such as Figure 1 As shown, the specific steps are as follows:

[0037] The hydrogenation catalyst is a fresh agent, wherein the oil-soluble catalyst is molybdenum isooctanoate; and the active components of the powder catalyst are Co and Mo.

[0038] The total active component content in the powdered catalyst is 30w% (the mass of the powdered catalyst is 100%), wherein the Co content is 5w%, the Mo content is 25w%, and the carrier is silicon oxide. The specific surface area of ​​the powdered catalyst is 600m 2 / g, pore volume is 0.6cm 3 / g.

[0039] Among them, the powdered catalyst is used after being treated with alkali, and the alkali treatment conditions are: the powdered catalyst is immersed in a potassium hydroxide solution with a concentration of 1.0 mol / L at 60°C for 0.5h, then washed with deionized water, dried at 80°C, and ground to obtain the powdered catalyst after alkali treatment.

[0040] Calculated on the basis of active components (metals), 300ppm of oil-soluble catalyst and 6wt% of powdered catalyst treated with alkali, waste plastic oil containing chlorine and silicon 2 and hydrogen 1 are introduced into a slurry bed reactor 3 from bottom to top, at 360°C, a reaction pressure of 8MPa, and a liquid hourly space velocity of 0.3h -1 , dechlorination and desiliconization reactions are carried out under the condition of a hydrogen-to-oil ratio of 600. The liquid phase obtained after gas, liquid and solid separation of the material discharged from the slurry bed reactor is the waste plastic oil product 4 after dechlorination and desiliconization. The gas phase contains unreacted hydrogen (which can be reused after purification), and the solid is a hydrogenation catalyst (which can be recycled to the slurry bed reactor for use until the hydrogenation catalyst is deactivated).

[0041] After the above hydrogenation catalyst is deactivated after multiple cycles of use (when Cl ≥ 0.2 μg / g or Si is greater than or equal to 1 μg / g in the waste plastic oil product after dechlorination and desiliconization, the hydrogenation catalyst is deemed to be deactivated), the deactivated hydrogenation catalyst (solid obtained by gas, liquid and solid separation) is calcined at 500°C for 8 hours, immersed in 100°C, 1.0 mol / L ammonia water for 3 hours, and then immersed in 60°C, 0.2 mol / L sodium hydroxide solution for 0.5 hours, washed with deionized water, dried, and ball-milled at room temperature to obtain a regenerated powder catalyst (the regenerated powder catalyst does not need to be treated with alkali again when used).

[0042] Example 2

[0043] This embodiment provides a method for hydrogenating, dechlorinating and desiliconizing waste plastic oil, wherein the hydrogenation catalyst used is a fresh agent, wherein the oil-soluble catalyst is molybdenum isooctanoate; the active metals of the powder catalyst are Co and W. Based on the mass of the active component (metal), the total active component content in the powder catalyst is 5w% (based on the mass of the powder catalyst as 100%), wherein the Co content is 0.5w%, the W content is 4.5w%, and the carrier is silicon oxide; the specific surface area of ​​the powder catalyst is 320m 2 / g, pore volume is 1.0cm 3 / g.

[0044] Among them, the powdered catalyst is used after being treated with alkali, and the alkali treatment conditions are:

[0045] The powdered catalyst was immersed in a sodium hydroxide solution at 100° C. and a concentration of 0.2 mol / L for 3 hours, then washed with deionized water, dried at 80° C., and ground to obtain an alkali-treated powdered catalyst.

[0046] Calculated on the basis of active components (metals), chlorine- and silicon-containing waste plastic oil 2 containing 1000 ppm of oil-soluble catalyst and 3 wt% of powdered catalyst treated with alkali is introduced into a slurry bed reactor 3 together with hydrogen 1 and flows from bottom to top at 400°C, a reaction pressure of 4 MPa, and a liquid hourly space velocity of 0.4 h -1 , dechlorination and desiliconization reactions are carried out under the condition of a hydrogen-to-oil ratio of 1000, and the materials discharged from the slurry bed reactor are separated into gas, liquid and solid to obtain a dechlorinated and desiliconized liquid waste plastic oil product 4.

[0047] After the above hydrogenation catalyst is deactivated after multiple cycles of use (when Cl ≥ 0.2 μg / g or Si ≥ 1 μg / g in the waste plastic oil product after dechlorination and desiliconization, the hydrogenation catalyst is deemed to be deactivated), the deactivated hydrogenation catalyst (solid obtained by gas, liquid and solid separation) is calcined at 600°C for 2h, immersed in 0.2mol / L ammonia water at 100°C for 0.5h, and then immersed in a mixed solution formed by mixing 1.0mol / L ammonia water and 0.2mol / L potassium hydroxide solution at a mass ratio of 2:1 at 60°C for 3h, washed with deionized water, dried, and ball-milled at room temperature to obtain a regenerated powder catalyst (the regenerated powder catalyst does not need to be treated with alkali again when used).

[0048] Example 3

[0049] This embodiment provides a method for hydrogenating, dechlorinating and desiliconizing waste plastic oil, wherein the powder catalyst in the hydrogenation catalyst used is the powder catalyst obtained after regeneration in Example 1; the oil-soluble catalyst is molybdenum isooctanoate;

[0050] Based on the active component (metal), chlorine- and silicon-containing waste plastic oil 2 containing 600 ppm of oil-soluble catalyst and 5 wt% of regenerated powdered catalyst is introduced into a slurry bed reactor 3 together with hydrogen 1 and flows from bottom to top at 380°C, a reaction pressure of 6 MPa, and a liquid hourly space velocity of 0.2 h -1 , dechlorination and desiliconization reactions were carried out under the condition of a hydrogen-to-oil ratio of 800, and the materials discharged from the slurry bed reactor were separated by gas, liquid and solid to obtain the dechlorinated and desiliconized waste plastic oil product 4.

[0051] After the above hydrogenation catalyst is deactivated after multiple cycles of use (when Cl ≥ 0.2 μg / g or Si is greater than or equal to 1 μg / g in the waste plastic oil product after dechlorination and desiliconization, the hydrogenation catalyst is deemed to be deactivated), the deactivated hydrogenation catalyst (solid obtained by gas, liquid and solid separation) is calcined at 550°C for 6 hours, immersed in 0.5 mol / L ammonia water at 80°C for 2 hours, and then immersed in a mixed solution formed by mixing 0.2 mol / L sodium hydroxide solution and 0.5 mol / L ammonia water at a mass ratio of 1:1 at 80°C for 2 hours, washed with deionized water, dried, and ball-milled at room temperature to obtain a regenerated powder catalyst (the regenerated powder catalyst does not need to be treated with alkali again when used).

[0052] Example 4

[0053] This embodiment provides a method for hydrogenating, dechlorinating and desiliconizing waste plastic oil, wherein the powder catalyst in the hydrogenation catalyst used is the powder catalyst obtained after regeneration in Example 2; the oil-soluble catalyst is molybdenum isooctanoate;

[0054] Calculated on the basis of active components (metals), chlorine- and silicon-containing waste plastic oil 2 containing 400 ppm of oil-soluble catalyst and 4 wt% of regenerated powdered catalyst and hydrogen 1 are introduced into a slurry bed reactor 3 from bottom to top, at 380°C, a reaction pressure of 8 MPa, and a liquid hourly space velocity of 0.1 h -1 , dechlorination and desiliconization reactions were carried out under the condition of a hydrogen-to-oil ratio of 300, and the materials discharged from the slurry bed reactor were separated into gas, liquid and solid to obtain the dechlorinated and desiliconized waste plastic oil product 4.

[0055] After the above hydrogenation catalyst is deactivated after multiple cycles of use (when Cl ≥ 0.2 μg / g or Si is greater than or equal to 1 μg / g in the waste plastic oil product after dechlorination and desiliconization, the hydrogenation catalyst is deemed to be deactivated), the deactivated hydrogenation catalyst (solid obtained by gas, liquid and solid separation) is calcined at 550°C for 4 hours, immersed in 100°C, 1.0 mol / L ammonia water for 2 hours, and then immersed in a mixed solution formed by mixing 1.0 mol / L potassium hydroxide solution and 0.2 mol / L ammonia water at a mass ratio of 1:2 at 60°C for 1 hour, washed with deionized water, dried, and ball-milled at room temperature to obtain a regenerated powder catalyst (the regenerated powder catalyst does not need to be treated with alkali again when used).

[0056] Example 5

[0057] This embodiment provides a method for hydrogenating, dechlorinating and desiliconizing waste plastic oil, wherein the hydrogenation catalyst used is a fresh agent, wherein the oil-soluble catalyst is molybdenum isooctanoate; the active metals of the powder catalyst are Co, Mo and W. Based on the mass of the active components (metals), the total active component content in the powder catalyst is 20w% (based on the mass of the powder catalyst as 100%), wherein the Co content is 3%, the Mo content is 10w%, the W content is 7w%, and the carrier is silicon oxide; the specific surface area of ​​the powder catalyst is 480m 2 / g, pore volume is 0.8cm 3 / g.

[0058] Among them, the powdered catalyst is used after being treated with alkali, and the alkali treatment conditions are:

[0059] The powdered catalyst was immersed in an aqueous ammonia solution with a concentration of 0.6 mol / L at 80° C. for 2 h, then washed with deionized water, dried at 80° C., and ground to obtain an alkali-treated powdered catalyst.

[0060] Calculated on the basis of active components (metals), chlorine- and silicon-containing waste plastic oil 2 containing 120 ppm of oil-soluble catalyst and 8 wt% of powdered catalyst is fed into a slurry bed reactor 3 together with hydrogen 1 and flows from bottom to top at 320°C, a reaction pressure of 10 MPa, and a liquid hourly space velocity of 0.1 h -1 , dechlorination and desiliconization reactions are carried out under the condition of a hydrogen-to-oil ratio of 1200, and the materials discharged from the slurry bed reactor are separated by gas, liquid and solid to obtain the dechlorinated and desiliconized waste plastic oil product 4.

[0061] After the above hydrogenation catalyst is deactivated after multiple cycles of use (when Cl ≥ 0.2 μg / g or Si is greater than or equal to 1 μg / g in the waste plastic oil product after dechlorination and desiliconization, the hydrogenation catalyst is deemed to be deactivated), the deactivated hydrogenation catalyst (solid obtained by gas, liquid and solid separation) is calcined at 650°C for 2h, immersed in 0.2mol / L ammonia water at 100°C for 0.5h, and then immersed in a mixed solution formed by mixing 1.0mol / L ammonia water and 0.2mol / L potassium hydroxide solution at a mass ratio of 1:2 at 60°C for 3h, washed with deionized water, dried, and ball-milled at room temperature to obtain a regenerated powder catalyst (the regenerated powder catalyst does not need to be treated with alkali again when used).

[0062] Comparative Example 1

[0063] The method for hydrogenating, dechlorinating and desiliconizing waste plastic oil provided in this comparative example is similar to that in Example 3, except that the hydrogenation catalyst used is different. The hydrogenation catalyst in this comparative example 1 only uses an oil-soluble catalyst (the same as the oil-soluble catalyst in Example 3).

[0064] Comparative Example 2

[0065] The method for hydrogenating, dechlorinating and desiliconizing waste plastic oil provided in this comparative example is similar to that in Example 1, except that a different hydrogenation catalyst is used. The hydrogenation catalyst in this comparative example 1 is only a powdered catalyst (the same as the powdered catalyst in Example 1).

[0066] Comparative Example 3

[0067] The method for hydrogenating, dechlorinating and desiliconizing waste plastic oil provided in this comparative example is similar to that in Example 1, except that a different hydrogenation catalyst is used. The powdered catalyst in the hydrogenation catalyst used in this comparative example 1 has not been treated with alkali.

[0068] The contents of Cl and Si in the waste plastic oil products after dechlorination and desiliconization obtained in the above-mentioned embodiments and comparative examples are shown in the following table.

[0069] Table 1

[0070]

[0071] From the data in the above table, it can be seen that the present invention uses a mixed catalyst formed by compounding an oil-soluble catalyst and an alkali-treated powdered catalyst to carry out a hydrogenation reaction in a slurry bed reactor, which can effectively improve the dechlorination and desiliconization effects of waste plastic oil. Moreover, since the powdered catalyst uses a silicon oxide carrier with a large specific surface area and a large pore volume, the powdered catalyst has a strong silicon-containing capacity and can effectively alleviate the problem that the catalyst is difficult to regenerate due to the adhesion of Si elements.

[0072] Of course, the present invention may have many other embodiments. Without departing from the spirit and essence of the present invention, technicians familiar with the field may make various corresponding changes and deformations based on the present invention, but these corresponding changes and deformations should all fall within the scope of protection of the claims of the present invention.

Claims

1. A method for hydrodechlorination and desiliconization of waste plastic oil, characterized in that: The method comprises the following steps: a hydrogenation catalyst, waste plastic oil and hydrogen flow from bottom to top in a slurry bed reactor to perform dechlorination and desiliconization reactions to obtain a waste plastic oil product with Cl<0.2μg / g and Si<1μg / g; Wherein, the hydrogenation catalyst is a composite catalyst formed by an oil-soluble catalyst and a powdered catalyst treated with alkali; The carrier of the powder catalyst is silicon oxide.

2. The method for hydrodechlorination and desiliconization of waste plastic oil according to claim 1, characterized in that: The alkali treatment process comprises: The powdered catalyst is immersed in an alkali solution of 0.2-1.0 mol / L at 60-100° C. for 0.5-3 h, and then washed, dried and ground to obtain an alkali-treated powdered catalyst.

3. The method for hydrodechlorination and desiliconization of waste plastic oil according to claim 2, characterized in that: The alkaline solution is selected from at least one of aqueous ammonia, sodium hydroxide and potassium hydroxide.

4. The method for hydrodechlorination and desiliconization of waste plastic oil according to claim 1, characterized in that: The active component of the powder catalyst comprises at least one of Co, Mo and W; and / or The active component of the oil-soluble catalyst is Mo.

5. The method for hydrodechlorination and desiliconization of waste plastic oil according to claim 4, characterized in that: Based on the mass of the powdered catalyst being 100%, the content of the active component in the powdered catalyst is 5wt%-30wt%.

6. The method for hydrodechlorination and desiliconization of waste plastic oil according to claim 1, characterized in that: The specific surface area of ​​the powder catalyst is 320-600m 2 / g, pore volume is 0.6-1cm 3 / g.

7. The method for hydrodechlorination and desiliconization of waste plastic oil according to claim 4, characterized in that: The oil-soluble catalyst and the powder-type catalyst are respectively calculated by the mass of the active components, and based on the mass of the waste plastic oil as 100%, the added amount of the oil-soluble catalyst is 100-2000ppm, and the added amount of the powder-type catalyst is 1wt%-10wt%; preferably, the added amount of the oil-soluble catalyst is 300-1000ppm, and the added amount of the powder-type catalyst is 3wt%-6wt%.

8. The method for hydrodechlorination and desiliconization of waste plastic oil according to claim 1, characterized in that: The temperature of the dechlorination and desiliconization reaction is 300-420°C, the pressure is 2-10MPa, and the liquid hourly space velocity is 0.1-0.6h -1 , hydrogen-to-oil ratio is 200-1200; Preferably, the temperature of the dechlorination and desiliconization reaction is 360-400°C, the pressure is 4-8MPa, and the liquid hourly space velocity is 0.1-0.4h -1 , the hydrogen-to-oil ratio is 600-1000.

9. The method for hydrodechlorination and desiliconization of waste plastic oil according to claim 1, characterized in that: When Cl≥0.2μg / g or Si≥1μg / g in the waste plastic oil product, the hydrogenation catalyst is deactivated; the deactivated hydrogenation catalyst is regenerated by calcination, primary alkali treatment, secondary alkali treatment, washing, drying and grinding.

10. The method for hydrodechlorination and desiliconization of waste plastic oil according to claim 9, characterized in that: The calcination temperature is 450-700° C., preferably 500-600° C., and the calcination time is 2-8 hours; and / or The alkaline solution used in the first alkaline treatment process is ammonia water; the alkaline solution used in the second alkaline treatment process is at least one of ammonia water, sodium hydroxide solution and potassium hydroxide solution.

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