A method of dechlorination

Abstract

The present application relates to a kind of dechlorination methods, comprising the following steps: (1) the dechlorination material to be contacted with dechlorination agent bed layer is passed into dechlorination agent, carries out adsorption dechlorination at 100~300 ℃, obtains dechlorination material, when the dechlorination agent bed layer is all penetrated, stop passing into the dechlorination material to be, obtains the dechlorination agent to be born;(2) at 100~300 ℃, inert gas is passed into the dechlorination agent to be born and is swept, then the inert gas containing water is passed into and is dechlorinated regeneration, then inert gas is passed into and is dried, obtains regeneration dechlorination agent;(3) the regeneration dechlorination agent is used in step (1) again and continues to carry out adsorption dechlorination.The present application realizes the adsorption dechlorination of the dechlorination material to be by using dechlorination agent, and can be dechlorinated regeneration to the dechlorination agent to be born by using the inert gas containing water and blowing treatment, so as to realize the recycling of alumina dechlorination agent, effectively improve the utilization of dechlorination agent, reduce the dechlorination operation cost, reduce the pollution of waste dechlorination agent to environment, improve the efficiency of dechlorination treatment.

Description

TECHNICAL FIELD

[0001] The present application relates to a method for dechlorination of materials in a refining plant, in particular, a method for dechlorination of materials related to catalytic reforming of naphtha. BACKGROUND

[0002] During the operation of a refining plant, due to the chlorine carried by the raw oil itself and the loss of chlorine by the catalyst itself, problems such as chlorine corrosion and ammonia salt corrosion plugging of downstream devices may occur, and stricter environmental protection chlorine emission indicators also require enterprises to adopt a feasible dechlorination scheme.

[0003] In the prior art, taking a continuous reforming device as an example, the following processes are mainly used for dechlorination of catalyst regeneration flue gas: (1) caustic washing process, which uses alkali to neutralize Cl and HCl in the flue gas. The caustic washing dechlorination not only needs to be matched with a regeneration chlorine injection tank, a regeneration water injection tank, an alkali cooling tank, an alkali circulating pump, a regeneration chlorine injection pump, a regeneration water injection pump and other equipment, but also needs to be treated twice to deal with the alkali-containing wastewater or salt-containing wastewater generated by the caustic washing system. At present, the salt concentration in the circulating alkali is often too high, causing the plugging of the regeneration vent gas washing tower or the venturi scrubber, thereby forcing the caustic washing system to stop working and affecting the normal production of the device. Some devices even shut down the caustic washing system, and the regeneration flue gas is directly or diluted and vented, causing air pollution. (2) Chlorsorb technology of UOP Company, which uses the catalyst to be regenerated to absorb chlorine in the regeneration flue gas and reduces the chlorine injection amount of the catalyst, and replaces the traditional caustic washing system. However, the Chlorsorb technology also has the following problems: the increase of the amount of reforming catalyst increases the initial investment of the device; as the operation time of the catalyst increases, the chlorine holding capacity of the catalyst decreases, the chlorine injection amount increases, and the chlorine in the vent gas will also gradually increase; although the chlorine in the vent gas is reduced, it still cannot meet the national environmental protection standards and needs to be diluted to meet the standards; since the carbon-containing spent catalyst absorbs water in the circulating coke-burning gas before entering the coke-burning system to burn coke, the water content in the coke-burning system will inevitably increase significantly, the specific surface area and chlorine holding capacity of the catalyst will decrease rapidly, and the service life of the catalyst will be shortened. (3) Solid dechlorination agent process, which uses a special dechlorination agent, restores the activity of the reforming catalyst well, significantly improves the quality of reforming gasoline, reduces the operating cost, optimizes the caustic washing dechlorination process, makes the regeneration flue gas meet the national emission standards, and reduces or eliminates the pollution of the regeneration flue gas to the environment, but the dechlorination agent cannot be regenerated after use, and the environmental protection treatment cost is high and difficult.

[0004] For product gas dechlorination and dechlorination before de-pentane of reforming generated oil, the solid dechlorination agent process is also currently used, and the gas phase or liquid phase product passes through a tank body containing the dechlorination agent once to remove chlorine and chlorides therein, and the same problems of short service life of the dechlorination agent, non-regeneration of the waste dechlorination agent and environmental protection treatment are also present. SUMMARY

[0005] The present application aims to provide a dechlorination method, which uses dechlorination agent that can be recycled and regenerated, improves the utilization of dechlorination agent, and solves the problem of environmental protection post-treatment.

[0006] To achieve the above-mentioned purpose, the first aspect of the present application provides a dechlorination method, comprising the following steps:

[0007] (1) passing the material to be dechlorinated into the bed of dechlorination agent to contact with the dechlorination agent, and performing adsorption dechlorination at 100-300°C to obtain dechlorinated material, wherein the dechlorination agent is alumina, the specific surface area of which is 200-300 m 2 / g, the pore volume is 0.4-1.0 mL / g, and the average pore diameter is 3-8 nm; when the bed of dechlorination agent is completely penetrated, the passing of the material to be dechlorinated is stopped, and the spent dechlorination agent is obtained;

[0008] (2) passing inert gas into the spent dechlorination agent at 100-300°C to perform purging, then passing water-containing inert gas to perform dechlorination regeneration, and then passing inert gas to perform drying, to obtain regenerated dechlorination agent;

[0009] (3) reusing the regenerated dechlorination agent in step (1) to continue the adsorption dechlorination.

[0010] The second aspect of the present application provides a continuous dechlorination method, comprising filling the bed of dechlorination agent in the first dechlorination tank and the second dechlorination tank, wherein the dechlorination agent is alumina, the specific surface area of which is 200-300 m 2 / g, the pore volume is 0.4-1.0 mL / g, and the average pore diameter is 3-8 nm; and then performing continuous dechlorination by the method comprising the following steps:

[0011] (a) passing the material to be dechlorinated into the first dechlorination tank;

[0012] (b) making the first dechlorination tank in adsorption dechlorination state, and performing adsorption dechlorination at 100-300°C; the adsorption dechlorination state is passing the material to be dechlorinated into the dechlorination tank, flowing through the bed of dechlorination agent along the axial direction of the dechlorination tank to perform the adsorption dechlorination, and obtaining the dechlorinated material from the outlet of the dechlorination tank;

[0013] (c) when the bed of dechlorination agent in the first dechlorination tank is completely penetrated, obtaining the spent dechlorination agent; passing the material to be dechlorinated into the second dechlorination tank, making the second dechlorination tank in the adsorption dechlorination state, and performing adsorption dechlorination on the material to be dechlorinated in the second dechlorination tank;

[0014] (d) the first dechlorination tank is in a regeneration state, the spent dechlorination agent in the first dechlorination tank is dechlorinated and regenerated, the regeneration state is that the feeding of the material to be dechlorinated is stopped, inert gas is introduced into the spent dechlorination agent at 100-300 DEG C to perform purging, then water-containing inert gas is introduced to perform dechlorination regeneration, and then inert gas is introduced to perform drying;

[0015] (e) when the dechlorination agent bed of the second dechlorination tank is fully penetrated, the material to be dechlorinated is introduced into the first dechlorination tank to perform adsorption dechlorination; and the second dechlorination tank is in the regeneration state, and the spent dechlorination agent in the second dechlorination tank is dechlorinated and regenerated.

[0016] In the method, alumina is used as the dechlorination agent to perform adsorption dechlorination on the material to be dechlorinated, and water-containing inert gas is used to perform dechlorination regeneration on the spent dechlorination agent obtained after adsorption penetration, and then the spent dechlorination agent is used for adsorption dechlorination again, so that the regeneration and recycling of the dechlorination agent are realized, the utilization rate of the dechlorination agent is effectively improved, the operation cost of dechlorination is reduced, and the pollution caused by the waste dechlorination agent to the environment is reduced.

[0017] Other features and advantages of the present application will be described in detail in the following specific embodiment part. BRIEF DESCRIPTION OF DRAWINGS

[0018] The accompanying drawings are included to provide a further understanding of the present application, and constitute a part of the specification, and are used together with the following specific embodiments to explain the present application, but do not constitute a limitation on the present application. In the drawings:

[0019] Figure 1 is a flow diagram of the continuous dechlorination method of the present application;

[0020] Figure 2 is a structural schematic diagram of the dechlorination tank used in the present application.

[0021] Explanation of reference signs

[0022] 1 first dechlorination tank 2 second dechlorination tank 3 first pipeline

[0023] 4 second pipeline 5 fourth pipeline 6 third pipeline

[0024] 7 first control valve 8 second control valve 9 fourth control valve

[0025] 10 third control valve 11 fifth control valve DETAILED DESCRIPTION

[0026] The specific embodiments of the present application are described in detail below in combination with the drawings. It should be understood that the specific embodiments described herein are only used to illustrate and explain the present application, and are not used to limit the present application.

[0027] In the present application, the orientation words such as "upper, lower" used herein generally refer to the upper and lower of the device in the normal use state, for example, referring to the figure surface direction of Figure 1 the device, "inner, outer" refers to relative to the device profile. In addition, the terms "first, second" are only for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. In the description of the present application, the meaning of "a plurality of" is two or more, unless otherwise explicitly specified.

[0028] The first aspect of the present application provides a dechlorination method, which comprises the following steps: (1) passing a material to be dechlorinated into a bed of dechlorination agent and contacting with the dechlorination agent to perform adsorption dechlorination at 100-300°C to obtain a dechlorinated material, the dechlorination agent being alumina with a specific surface area of 200-300 m 2 / g, a pore volume of 0.4-1.0 mL / g, and an average pore diameter of 3-8 nm, when the bed of the dechlorination agent is fully penetrated, the passage of the material to be dechlorinated is stopped to obtain a spent dechlorination agent; (2) passing an inert gas into the spent dechlorination agent at 100-300°C to perform purging, then passing a water-containing inert gas to perform dechlorination regeneration, and then passing an inert gas to perform drying to obtain a regenerated dechlorination agent; (3) reusing the regenerated dechlorination agent in step (1) to continue the adsorption dechlorination.

[0029] The alumina dechlorination agent used in the present application can realize adsorption dechlorination of the material to be dechlorinated, and can realize dechlorination regeneration of the spent dechlorination agent obtained after adsorption penetration by using a water-containing inert gas, and then be reused for adsorption dechlorination, so that the dechlorination agent can be recycled, the utilization rate of the dechlorination agent can be effectively improved, the cost of dechlorination operation can be reduced, and the pollution of waste dechlorination agent to the environment can be reduced.

[0030] In a preferred embodiment of the present application, the dechlorination agent is alumina containing sulfate, wherein the content of sulfate is 0.2-4.0 mass% based on alumina, preferably 0.2-3.5 mass%.

[0031] In a preferred embodiment of the present application, the specific surface area of the dechlorination agent can be 240-300 m 2 / g, the average pore diameter is 3-8 nm, and the pore volume is 0.4-0.8 mL / g. Preferably, the dechlorination agent has 15-30 vol% of pores with a pore diameter of 1-3 nm, 40-60 vol% of pores with a pore diameter of 4-6 nm, and 10-30 vol% of pores with a pore diameter of 6-12 nm.

[0032] In order to further improve the effect of adsorption dechlorination, in one specific embodiment of the present application, in step (1), the adsorption pressure for adsorption dechlorination is 0.2-1.0 MPa, preferably 0.5-0.8 MPa, and the temperature for adsorption dechlorination is preferably 200-300℃, and when the chlorine content of the dechlorination material is greater than 0.5 μg / g, the bed of the dechlorination agent is fully penetrated.

[0033] In one specific embodiment of the present application, in step (2), the time for purging the spent dechlorination agent with inert gas is 0.5-3 h, preferably 1-2 h; the water content in the aqueous inert gas used for dechlorination regeneration can vary in a wide range, preferably 0.1-35 vol%, more preferably 5-35 vol%, and further preferably 20-30 vol%; the time for dechlorination regeneration is 0.5-3 h; the time for drying with inert gas is 0.5-3 h, preferably 1-2 h. The temperature for dechlorination regeneration control in step (2) is preferably 200-300℃, and the pressure is preferably 0.1-0.2 MPa.

[0034] According to the present application, the chlorine-containing gas generated in the process of dechlorination regeneration in step (2) is washed with lye to obtain regenerated dechlorination gas, and the regenerated dechlorination gas is dried and returned to step (2) as inert gas for continuous use, so as to realize the recycling of regenerated dechlorination gas and save the amount of inert gas. In one embodiment of the present application, the chlorine-containing gas can be introduced into lye to neutralize the chlorides therein. Further, the lye is a solution containing NaOH and / or Ca(OH)2, and preferably the lye is an aqueous solution containing NaOH, and the concentration of the lye can vary in a wide range, and the concentration of the lye can be 5-15 mass% based on the total weight of the lye.

[0035] According to the present application, the material to be dechlorinated can be a gas to be dechlorinated or a liquid to be dechlorinated. In one embodiment of the present application, the gas to be dechlorinated is recycled hydrogen gas for catalytic reforming of naphtha or flue gas for regeneration of reforming catalyst, and the chlorine content in the gas to be dechlorinated can be 1-1000 μg / g, preferably 1-400 μg / g; the liquid to be dechlorinated is reformate, and the chlorine content in the liquid to be dechlorinated can be 1-8 μg / g, preferably 1-6 μg / g. Preferably, the volume ratio of the gas to be dechlorinated to the dechlorination agent is 600-1500:1, and the liquid / solid mass ratio of the liquid to be dechlorinated to the dechlorination agent is 5-10:1.

[0036] In one specific embodiment of the present application, the inert gas is preferably N2.

[0037] According to the present application, the preparation step of the dechlorination agent can comprise mixing pseudoboehmite, water and peptizing agent for peptization mixing and kneading, and then shaping, drying and calcining to obtain the dechlorination agent.

[0038] In a preferred embodiment of the present application, the peptizing agent can be an aqueous nitric acid solution, the content of the nitric acid in the aqueous nitric acid solution can be 50-80 mass%, preferably 60-70 mass%; the amount of water can be 50-120 mass%, preferably 50-100 mass%, more preferably 70-90 mass%, based on the mass of the pseudo-boehmite; the amount of the peptizing agent can be 0.5-5 mass%, preferably 1-3 mass%, more preferably 1-2 mass%; the drying temperature can be 100-150°C, preferably 110-150°C, more preferably 110-130°C, and the drying time can be 2-8h, preferably 4-8h, more preferably 4-6h; the calcination temperature can be 450-650°C, preferably 500-550°C, and the calcination time can be 2-8h, preferably 4-8h.

[0039] According to the present application, the pseudo-boehmite can contain 0.2-4.0 mass%, preferably 0.2-3.5 mass% of sulfate, based on the content of aluminum oxide.

[0040] The second aspect of the present application provides a method for continuous dechlorination, which comprises loading a bed of dechlorination agent in a first dechlorination tank and a second dechlorination tank, the dechlorination agent being aluminum oxide with a specific surface area of 200-300m 2 / g, a pore volume of 0.4-1.0mL / g, and an average pore diameter of 3-8nm; and then performing continuous dechlorination in the following steps:

[0041] (a) passing the material to be dechlorinated into the first dechlorination tank;

[0042] (b) bringing the first dechlorination tank into an adsorption dechlorination state, and performing adsorption dechlorination at 100-300°C; the adsorption dechlorination state is passing the material to be dechlorinated into the dechlorination tank, flowing through the bed of dechlorination agent along the axial direction of the dechlorination tank to perform the adsorption dechlorination, and obtaining the dechlorinated material from the outlet of the dechlorination tank;

[0043] (c) when the bed of dechlorination agent in the first dechlorination tank is fully penetrated, obtaining spent dechlorination agent; passing the material to be dechlorinated into the second dechlorination tank, and bringing the second dechlorination tank into the adsorption dechlorination state, and performing adsorption dechlorination on the material to be dechlorinated in the second dechlorination tank;

[0044] (d) bringing the first dechlorination tank into a regeneration state, and performing dechlorination regeneration on the spent dechlorination agent in the first dechlorination tank; the regeneration state is stopping the feeding of the material to be dechlorinated, passing inert gas through the spent dechlorination agent to perform purging at 100-300°C, then passing water-containing inert gas to perform dechlorination regeneration, and then passing inert gas to perform drying,

[0045] (e) When the dechlorinating agent bed in the second dechlorination tank is completely penetrated, the material to be dechlorinated is switched to be introduced into the first dechlorination tank for adsorption and dechlorination; and the second dechlorination tank is put into the regeneration state to dechlorinate and regenerate the dechlorinating agent in the second dechlorination tank.

[0046] According to the present invention, in step (b), the pressure of adsorption and dechlorination is 0.2 to 1.0 MPa, more preferably 0.5 to 0.8 MPa.

[0047] According to the present invention, in steps (c) and (e), when the chlorine content of the dechlorinated material flowing out of the outlet of the dechlorination tank is greater than 0.5 μg / g, the dechlorination agent bed is completely penetrated.

[0048] In one specific embodiment of the present invention, the dechlorinating agent is sulfate-containing alumina, wherein the sulfate content, based on alumina, is 0.2–4.0% by mass, preferably 0.2–3.5% by mass.

[0049] In one specific embodiment of the present invention, the time for purging the dechlorinating agent with inert gas is 0.5 to 3 hours; the water content in the inert gas used for dechlorination regeneration is 5 to 35% by volume, and the time is 0.5 to 3 hours; the inert gas is nitrogen; and the drying time with inert gas is 0.5 to 3 hours.

[0050] The following is in conjunction with the appendix Figure 1 This invention describes a continuous dechlorination method.

[0051] In one specific embodiment of the present invention, such as Figure 1 As shown, the first control valve 7 is opened, and the second control valve 8, the third control valve 10, the fourth control valve 9 and the fifth control valve 11 are closed, so that the material to be dechlorinated enters the first dechlorination tank 1 through the first pipeline 3 and flows axially through the dechlorinating agent bed to contact the dechlorinating agent, and is adsorbed and dechlorinated at 100-300℃, and the dechlorinated material is obtained from the outlet of the first dechlorination tank 1.

[0052] When the bed of dechlorination agent in the first dechlorination tank 1 is fully penetrated, the first control valve 7 is closed and the second control valve 8 is opened, so that the material to be dechlorinated is fed into the second dechlorination tank 2 through the second pipeline 4, and the material to be dechlorinated enters the second dechlorination tank 2 and flows through the bed of dechlorination agent in the axial direction to contact the dechlorination agent, and adsorption dechlorination is carried out at 100-300℃, and the dechlorinated material is obtained from the outlet of the second dechlorination tank 2; when the second dechlorination tank is dechlorinated, the spent dechlorination agent obtained after the adsorbed chlorine in the first dechlorination tank 1 is fully penetrated is in a regenerated state, and the fifth control valve 11 and the fourth control valve 9 need to be kept closed, the third control valve 10 is opened, and inert gas is fed into the first dechlorination tank 1 through the third pipeline 6 to purge the spent dechlorination agent at 100-300℃, and the purge gas flows out from the bottom of the first dechlorination tank 2, after the purging is completed, the fifth control valve 11 is opened, water is injected into the inert gas in the third pipeline 6, and the inert gas containing water is fed into the first dechlorination tank 1 to regenerate the spent dechlorination agent, and finally the fifth control valve 11 is closed, so that the inert gas is fed into the first dechlorination tank 1 through the third pipeline 6 to dry the spent dechlorination agent, so that the spent dechlorination agent in the first dechlorination tank 1 is regenerated, and after the regeneration is completed, the third control valve 10 is closed.

[0053] When the bed of dechlorination agent in the second dechlorination tank 2 is fully penetrated, the spent dechlorination agent is obtained, the first control valve 7 is opened and the second control valve 8 is closed, so that the material to be dechlorinated is fed into the first dechlorination tank 1 through the first pipeline 3 to carry out adsorption dechlorination; when the first dechlorination tank is dechlorinated, the spent dechlorination agent obtained after the adsorbed chlorine in the second dechlorination tank 2 is fully penetrated is in a regenerated state, and the fifth control valve 11 and the third control valve 10 need to be closed first, the fourth control valve 9 is opened, and inert gas is fed into the second dechlorination tank 2 through the fourth pipeline 5 to purge the spent dechlorination agent, and the purge gas flows out from the bottom of the first dechlorination tank 1, after the purging is completed, the fifth control valve 11 is opened, water is injected into the inert gas in the fourth pipeline 5, and the inert gas containing water is fed into the second dechlorination tank 2 to regenerate the spent dechlorination agent, and finally the fifth control valve 11 is closed, so that the inert gas is fed into the second dechlorination tank 2 through the fourth pipeline 5 to dry the spent dechlorination agent, so that the spent dechlorination agent in the second dechlorination tank 2 is regenerated, and after the regeneration is completed, the fourth control valve 9 is closed. The above steps are repeated to realize continuous dechlorination. In the above process, the chlorine-containing gas generated after the spent dechlorination agent is regenerated using the inert gas containing water is washed using lye, and the regenerated dechlorination gas obtained after drying can be used as inert gas for recycling.

[0054] The application will be further described by the following examples, but the application is not limited in any way by the examples.

[0055] The switching condition in the following examples is that the chlorine content in the outlet effluent of the dechlorination tank in the adsorption dechlorination state is greater than 0.5 μg / g.

[0056] The breakthrough condition of the dechlorination agent in the following comparative examples is that the chlorine content in the oil or gas flowing out of the dechlorination tank is more than 0.5 μg / g.

[0057] Example 1

[0058] The dechlorination agent of the present application was prepared.

[0059] 100 g of pseudo-boehmite powder (produced by Hunan Changling Catalyst Factory, trademark ASIA, alumina content 75 mass%, sulfate content 1.5 mass% (the same below) based on alumina) was mixed with 80 g of deionized water, 1.5 g of 65 mass% nitric acid solution was added for peptization and kneading, and then extruded into a strip, dried at 120°C for 4 hours, and calcined at 500°C for 4 hours to obtain γ-alumina with a sulfate content of 1.5 mass% based on alumina as the dechlorination agent E1. The specific surface area of the dechlorination agent E1 was 280 m 2 / g, the pore volume was 0.6 mL / g, and the average pore diameter was 5 nm, wherein the pore diameter of 1-3 nm accounted for 25 vol%, the pore diameter of 4-6 nm accounted for 55 vol%, and the pore diameter of 6-12 nm accounted for 20 vol%.

[0060] Example 2

[0061] The dechlorination agent E2 of the present application was prepared.

[0062] The alumina containing sulfate was prepared by the same method as in Example 1, except that the sulfate content of the pseudo-boehmite was 0.3 mass% based on alumina. The dechlorination agent E2 was prepared, wherein the sulfate content was 0.3 mass% based on alumina.

[0063] Example 3

[0064] The dechlorination agent E3 of the present application was prepared.

[0065] The alumina containing sulfate was prepared by the same method as in Example 1, except that the sulfate content of the pseudo-boehmite was 2.0 mass% based on alumina. The dechlorination agent E3 was prepared, wherein the sulfate content was 2.0 mass% based on alumina.

[0066] Example 4

[0067] The dechlorination agent E4 of the present application was prepared.

[0068] The alumina containing sulfate was prepared by the same method as in Example 1, except that the sulfate content of the pseudo-boehmite was 3.5 mass% based on alumina. The dechlorination agent E4 was prepared, wherein the sulfate content was 3.5 mass% based on alumina.

[0069] Comparative Example 1

[0070] Preparation of conventional reforming generated oil dechlorination agent.

[0071] Take 30 g of γ-Al2O3 (produced by Shanghai Xinnian Petrochemical Additives Co., Ltd.), 30 g of X zeolite and 30 g of Ca(OH)2, mix them uniformly, add 40 g of zinc oxide, 5 g of methyl cellulose and 2.5 g of sesbania powder, then add 35 mL of 33 mass% nitric acid and 75 mL of deionized water, mix and knead uniformly, extrude into strips, dry at 120 ℃ for 2 hours, and calcine at 650 ℃ for 4 hours to obtain the dechlorination agent A, which contains 24 mass% of alumina, 20 mass% of X zeolite, 24 mass% of CaO and 32 mass% of ZnO.

[0072] Comparative Example 2

[0073] Preparation of conventional reforming recycle hydrogen dechlorination agent.

[0074] Take 40 g of pseudo-boehmite (produced by Shandong Aluminum Factory, with an alumina content of 69 mass%), 20 g of white clay and 40 g of ZnO, mix them uniformly, add 4 mL of 65 mass% nitric acid and 30 mL of deionized water, mix and knead, extrude into strips with a 2 mm diameter hole plate, let the extrudates stand at 20 ℃ for 4 hours, dry at 120 ℃ for 4 hours, and calcine at 450 ℃ for 4 hours to obtain the dechlorination agent B, which contains 31.5 mass% of alumina, 22.8 mass% of white clay and 45.7 mass% of ZnO.

[0075] Comparative Example 3

[0076] Preparation of conventional reforming catalyst regeneration flue gas dechlorination agent.

[0077] Take 15 g of pseudo-boehmite (produced by Shandong Aluminum Factory, with an alumina content of 69 mass%), 20 g of bentonite and 80 g of calcium hydroxide, mix them, add 2 g of methyl cellulose and 2 g of sesbania powder, mix them uniformly, then add 15 mL of 33 mass% nitric acid and 45 mL of deionized water, mix and knead uniformly, extrude into strips, and calcine at 650 ℃ for 4 hours to obtain the dechlorination agent C, which contains 70 mass% of calcium oxide, 15 mass% of bentonite and 15 mass% of alumina.

[0078] Example 5

[0079] Continuous dechlorination of reforming generated oil.

[0080] The dechlorination of reforming generated oil is carried out by using the flow shown in Figure 1 The first dechlorination tank 1 and the second dechlorination tank 2 are filled with 24 g of the dechlorination agent E1 prepared in Example 1 in three sections, separated by quartz glass filaments, and the loading amount of each section is 8 g. The specific steps include:

[0081] The first dechlorination tank 1 is in adsorption dechlorination state and is heated to 40°C, and the dechlorination of the reforming product oil with chlorine content of 5 μg / g is carried out by blowing N2 for 15 min, and the dechlorination product is obtained from the lower part of the dechlorination tank. The liquid / solid mass ratio of the reforming product oil and the dechlorination agent E1 is 7.5:1.

[0082] When the chlorine content in the reforming product oil flowing out of the first dechlorination tank 1 is 0.5 μg / g, the reforming product oil to be dechlorinated is switched to the second dechlorination tank 2, and the adsorption dechlorination is carried out under the control of the pressure of 0.8 MPa, wherein the liquid / solid mass ratio of the reforming product oil and the dechlorination agent E1 is 7.5:1. At this time, the first dechlorination tank 1 is in regeneration state, and the spent dechlorination agent is regenerated by blowing N2 for 0.5 h and then blowing N2 with water content of 20% by volume for 2 h to remove the chlorine and chlorides adsorbed on the dechlorination agent, and then blowing N2 for 2 h to dry to obtain the regenerated dechlorination agent. The chlorine-containing gas produced by blowing N2 with water content of 20% by volume in the above process is blown into a sodium hydroxide solution with concentration of 10% by mass to remove chlorides to obtain regenerated dechlorination gas, and the regenerated dechlorination gas is dried and used as inert gas.

[0083] When the chlorine content in the reforming product oil flowing out of the second dechlorination tank 2 is greater than 0.5 μg / g (i.e. the switching condition is reached), the reforming product oil to be dechlorinated is switched to the first dechlorination tank 1 for adsorption dechlorination, and the second dechlorination tank 2 is in regeneration state, and the spent dechlorination agent in the second dechlorination tank is regenerated by the same method as that for the spent dechlorination agent in the first dechlorination tank.

[0084] The dechlorination effect is shown in Table 1, wherein the breakthrough chlorine content refers to the chlorine content on the dechlorination agent filled in the tank when the chlorine content in the dechlorination tank effluent is greater than 0.5 μg / g.

[0085] Comparative Example 4

[0086] Reforming product oil dechlorination.

[0087] In the same way as Figure 2The dechlorination tank 5 shown is filled with 24 g of dechlorination agent A in three sections separated by quartz glass filaments, with 8 g in each section. The temperature is raised to 40°C, and the tank is purged with N2for 15 min. The reforming hydrogen gas with a chlorine content of 5 μg / g is introduced, and the pressure is controlled at 0.8 MPa. The liquid / solid mass ratio of the reforming hydrogen gas to the dechlorination agent A is 7.5:1. When the chlorine content in the reforming hydrogen gas flowing out of the dechlorination tank is greater than 0.5 μg / g, it is considered that the entire dechlorination agent has been penetrated. The dechlorination effect is shown in Table 1. The dechlorination agent A cannot be regenerated after chlorine penetration.

[0088] Table 1

[0089]

[0090]

[0091] Example 6

[0092] The method in Example 5 is used for reforming cycle hydrogen dechlorination, except that:

[0093] The first dechlorination tank 1 and the second dechlorination tank 2 are each filled with 12 g of the dechlorination agent El prepared in Example 1 in three sections separated by quartz glass filaments, with 4 g in each section;

[0094] In the adsorption dechlorination state, the first dechlorination tank 1 or the second dechlorination tank 2 is first purged with N2at 20°C for 15 min, and then the reforming hydrogen gas with a chlorine content of 50 μg / g is introduced. The pressure for adsorption dechlorination is controlled at 0.2 MPa. The gas / agent volume ratio of the reforming cycle hydrogen gas to the dechlorination agent El is 1000:1.

[0095] The dechlorination effect is shown in Table 2.

[0096] Comparative Example 5

[0097] The method in Comparative Example 4 is used for reforming cycle hydrogen dechlorination, except that: Figure 2 The dechlorination tank 5 shown is filled with 24 g of dechlorination agent A in three sections separated by quartz glass filaments, with 8 g in each section. The temperature is raised to 40°C, and the tank is purged with N2for 15 min. The reforming hydrogen gas with a chlorine content of 5 μg / g is introduced, and the pressure is controlled at 0.8 MPa. The liquid / solid mass ratio of the reforming hydrogen gas to the dechlorination agent A is 7.5:1. When the chlorine content in the reforming hydrogen gas flowing out of the dechlorination tank is greater than 0.5 μg / g, it is considered that the entire dechlorination agent has been penetrated. The dechlorination effect is shown in Table 1. The dechlorination agent A cannot be regenerated after chlorine penetration.

[0098] Table 2

[0099]

[0100]

[0101] Example 7

[0102] The method of Example 5 was used to dechlorinate reformer regeneration flue gas, except that:

[0103] In the adsorptive dechlorination state, the first dechlorination tank 1 or the second dechlorination tank 2 was warmed to 120°C, purged with N2 for 15 min, and then the reformer regeneration flue gas with a chlorine content of 200 μg / g was introduced, which contained 78 vol% nitrogen, 8 vol% oxygen, 13 vol% CO2, and the remainder water vapor. The adsorptive dechlorination was carried out at 0.8 MPa and a gas / catalyst volume ratio of 1000:1 of the reformer regeneration flue gas to the dechlorination agent El.

[0104] The dechlorination effect is shown in Table 3.

[0105] Comparative Example 6

[0106] The method of Comparative Example 4 was used to dechlorinate reformer regeneration flue gas, except that: Figure 2 The dechlorination tank 5 was filled with 24 g of the dechlorination agent C in three sections, separated by quartz glass filaments, with 8 g in each section, warmed to 300°C, purged with N2 for 15 min, and then the reformer regeneration flue gas with a chlorine content of 200 μg / g was introduced, which contained 78 vol% nitrogen, 8 vol% oxygen, 13 vol% CO2, and the remainder water vapor. The dechlorination was carried out at 0.8 MPa and a gas / catalyst volume ratio of 1000:1 of the reformer regeneration flue gas to the dechlorination agent C. When the chlorine content of the regeneration flue gas flowing out of the dechlorination tank was greater than 0.5 μg / g, it was considered that the entire dechlorination agent was penetrated. The dechlorination effect is shown in Table 3.

[0107] Table 3

[0108]

[0109]

[0110] Example 8

[0111] The method of Example 6 was used to dechlorinate the reformer recycle hydrogen, except that the dechlorination agent used was the dechlorination agent E2 prepared in Example 2. The dechlorination effect is shown in Table 4.

[0112] Example 9

[0113] The method of Example 6 was used to dechlorinate the reformer recycle hydrogen, except that the dechlorination agent used was the dechlorination agent E3 prepared in Example 3. The dechlorination effect is shown in Table 4.

[0114] Example 10

[0115] The method of example 6 was used to dechlorinate the reforming cycle hydrogen, except that the dechlorination agent used was the dechlorination agent E4 prepared in example 4. The dechlorination effect is shown in table 4.

[0116] Table 4

[0117]

[0118] Example 11

[0119] The method of example 7 was used to dechlorinate the reforming catalyst regeneration flue gas, except that when the dechlorination tank was in the regenerated state, the water content in the water-containing N2 passed into the dechlorination tank was 10% by volume, and the dechlorination effect is shown in table 5.

[0120] Example 12

[0121] The method of example 7 was used to dechlorinate the reforming catalyst regeneration flue gas, except that when the dechlorination tank was in the regenerated state, the water content in the water-containing N2 passed into the dechlorination tank was 30% by volume, and the dechlorination effect is shown in table 5.

[0122] Comparative example 7

[0123] The method of example 7 was used to dechlorinate the reforming catalyst regeneration flue gas, except that when the dechlorination tank was in the regenerated state, the gas passed into the dechlorination tank was always water-free N2, and the dechlorination effect is shown in table 5.

[0124] Table 5

[0125]

[0126] According to tables 1-5, from the dechlorination data of examples 5-7 and comparative examples 4-6, compared with conventional dechlorination agents, the method of the present application can enable the dechlorination agent to be used for adsorption dechlorination after being regenerated for multiple cycles, the total usage rate is much higher than that of conventional dechlorination agents, and can achieve continuous dechlorination of the material to be dechlorinated, reducing the cost of the dechlorination process and reducing the pollution of waste dechlorination agents to the environment. From the comparison of the results of example 7, example 11, example 12 and comparative example 7, it can be seen that the use of water-containing inert gas for the spent dechlorination agent and adsorption dechlorination can effectively remove chlorine from the spent dechlorination agent, and the dechlorination regeneration effect is good, and preferably, when the water content in the water-containing inert gas is 20-30% by volume, the dechlorination regeneration effect is better.

[0127] The preferred embodiments of the present application are described in detail above with reference to the accompanying drawings, but the present application is not limited to the specific details in the above-described embodiments, and various simple modifications can be made to the technical solutions of the present application within the technical concept of the present application, and these simple modifications all belong to the protection scope of the present application.

[0128] It should be further noted that the various technical features described in the above detailed description can be combined in any suitable manner without departing from the scope of the application. To avoid not necessary repetition regarding various combinations, no further combinations will be described.

[0129] Moreover, the various embodiments described herein can be combined in any suitable manner, as long as such combinations do not depart from the scope of the present application.

Claims

1. A dechlorination method, comprising the following steps: (1) passing a material to be dechlorinated into a bed of a dechlorination agent to contact with the dechlorination agent, adsorptive dechlorination is carried out at 100-300℃ to obtain a dechlorinated material, the specific surface area of the dechlorination agent is 200-300m 2 / g, the pore volume is 0.4-1.0mL / g, the average pore diameter is 3-8nm, the dechlorination agent is alumina containing sulfate, wherein the content of sulfate is 0.2-4.0% by mass based on alumina, when the bed of the dechlorination agent is completely penetrated, the passing of the material to be dechlorinated is stopped, and a green dechlorination agent is obtained; (2) introducing inert gas into the spent dechlorination agent at 100-300°C to perform purging, then introducing water-containing inert gas to perform dechlorination regeneration, and then introducing inert gas to perform drying, to obtain regenerated dechlorination agent; wherein, The water content in the inert gas used for dechlorination regeneration is 5-35% by volume, and the time is 0.5-3 hours. (3) The regenerated dechlorinating agent is reused in step (1) to continue the adsorption dechlorination.

2. The method of claim 1, wherein, The specific surface area of the dechlorination agent is 240 to 300 m 2 / g, the pore volume is 0.4 to 0.8 mL / g, the average pore diameter is 3 to 8 nm; and the content of sulfate in the alumina is 0.2 to 3.5 mass%.

3. The method of claim 1, wherein, In step (1), the adsorption dechlorination pressure is 0.2~1.0MPa, and when the chlorine content of the dechlorinated material is greater than 0.5μg / g, the dechlorination agent bed is completely penetrated.

4. The method of claim 1, wherein, In step (2), the time for purging the dechlorinating agent with inert gas is 0.5~3h; The drying time using inert gas is 0.5 to 3 hours.

5. The method of claim 1, wherein, In step (2), the dechlorination regeneration process introduces an inert gas containing water to generate chlorine gas. The chlorine gas generated is then washed with an alkaline solution to obtain regenerated dechlorinated gas. After drying, the regenerated dechlorinated gas is returned to step (2) as an inert gas for continued use. The alkaline solution is a solution containing NaOH and / or Ca(OH)2.

6. The method of claim 1, wherein, The material to be dechlorinated is a gas or liquid to be dechlorinated. The gas to be dechlorinated is recycled hydrogen used in naphtha catalytic reforming or flue gas regenerated from the reforming catalyst. The liquid to be dechlorinated is reformed oil. The chlorine content in the gas to be dechlorinated is 1~400 μg / g, and the chlorine content in the liquid to be dechlorinated is 1~8 μg / g. The inert gas is nitrogen.

7. The method of claim 1, wherein, The preparation steps of the dechlorination agent include: mixing boehmite, water and a peptizing agent for sol-kneading, then molding, drying and calcining.

8. The method of claim 7, wherein, The adhesive solvent is an aqueous solution with a nitric acid content of 50-80% by mass; Based on the mass of the pseudoboehmite, the amount of water used is 50-120% by mass, and the amount of the adhesive solvent is 1-3% by mass. The drying temperature is 120~150℃ and the time is 4~8h; the calcination temperature is 500~550℃ and the time is 4~8h.

9. A continuous dechlorination method, comprising filling a dechlorination agent bed in a first dechlorination tank and a second dechlorination tank, wherein the specific surface area of ​​the dechlorination agent is 200~300m². 2 / g, pore volume is 0.4~1.0mL / g, average pore diameter is 3~8nm; the dechlorinating agent is sulfate-containing alumina, wherein the sulfate content is 0.2~4.0% by mass based on alumina; then continuous dechlorination is carried out according to the following steps: (a) The material to be dechlorinated is introduced into the first dechlorination tank; (b) The first dechlorination tank is placed in an adsorption dechlorination state and adsorption dechlorination is carried out at 100~300℃; the adsorption dechlorination state is that the material to be dechlorinated is introduced into the dechlorination tank and flows through the dechlorinating agent bed along the axial direction of the dechlorination tank for adsorption dechlorination, and the dechlorinated material is obtained from the outlet of the dechlorination tank; (c) When the dechlorinating agent bed in the first dechlorination tank is completely penetrated, a dechlorinating agent to be produced is obtained; the material to be dechlorinated is introduced into the second dechlorination tank, so that the second dechlorination tank is in the adsorption dechlorination state, and the material to be dechlorinated is adsorbed and dechlorinated in the second dechlorination tank; (d) putting the first dechlorination tank into a regeneration state to perform dechlorination regeneration on the spent dechlorination agent in the first dechlorination tank, the regeneration state being stopping feeding of the material to be dechlorinated, introducing inert gas into the spent dechlorination agent to perform purging at 100-300°C, then introducing water-containing inert gas to perform dechlorination regeneration, and then introducing inert gas to perform drying; wherein, The water content in the inert gas used for dechlorination regeneration is 5-35% by volume. (e) When the dechlorinating agent bed in the second dechlorination tank is completely penetrated, the material to be dechlorinated is introduced into the first dechlorination tank for adsorption and dechlorination; and the second dechlorination tank is put into the regeneration state to dechlorinate and regenerate the dechlorinating agent in the second dechlorination tank.

10. The method of claim 9, wherein, In steps (c) and (e), when the chlorine content of the dechlorinated material flowing out of the dechlorination tank is greater than 0.5 μg / g, the dechlorination agent bed is completely penetrated.

11. The method of claim 9, wherein, The inert gas mentioned is nitrogen.

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