Method for reducing nitrogen content in flare gas recovery treatment
By adding branches of the nitrogen treatment system to the torch gas treatment system, pretreatment and catalytic combustion, the problems of high load and large energy consumption of the torch gas recovery system are solved, and effective component recovery and combustion quality improvement are achieved.
Patent Information
- Application Number
- CN202411240722.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-05
- Publication Date
- 2024-12-20
AI Technical Summary
The torch gas mixture recycling treatment leads to a large load on the recycling system, a long recycling process for invalid components, high energy consumption, and a large amount of regenerated nitrogen is discharged to the torch system, resulting in high energy consumption for recycling and poor combustion quality.
Add branches of the nitrogen treatment system, carry out targeted separate treatment, first pretreatment of heavy metals, then mix with compressed air for catalytic hydrocarbon combustion reaction, use a carrier to carry Ag and Pt catalysts for catalytic combustion, and then change the mixture after the reaction. Heat cooling is directly discharged.
It reduces the nitrogen content in torch gas recovery treatment, reduces system load and processing energy consumption, improves combustion quality, reduces economic costs and environmental pollution pressure, and improves treatment efficiency.
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Figure BDA0005029175390000081
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of petrochemical industry, and in particular to a method for reducing nitrogen content in flare gas recovery treatment. Background Art
[0002] At present, the flare gas recovery system of refineries mostly adopts the combination of gas cabinet and compressor for recovery. The low-pressure gas of each device is first stored in the gas cabinet through the pipeline network to the main bus, and then sent to the high-pressure gas pipeline network as fuel gas after being pressurized by the compressor for recovery. Nitrogen passes through the refiner and other equipment in the purge device, so that the refiner and other equipment can be reused, while the regenerated nitrogen from the refiner and other equipment cannot meet the standards for discharge into the atmosphere and must be discharged into the flare gas pipeline network, so a large amount of high-temperature regenerated nitrogen will be discharged into the flare gas system.
[0003] Therefore, the disadvantages of the prior art mainly include: first, the mixed recovery treatment of flare gas will lead to a large load on the recovery system, a long recovery process of invalid components, and high energy consumption; second, a large amount of regenerated nitrogen is discharged into the flare system, which will make the flare gas recovery load high and the nitrogen content of the gas high, which will lead to high recovery energy consumption and poor combustion quality.
[0004] That is, the large amount of nitrogen emission in the regenerated gas causes problems such as high flare gas recovery load, high nitrogen content in gas, high recovery energy consumption, and poor combustion quality. Summary of the invention
[0005] In order to solve the problems of large system load, long invalid component recovery process and high energy consumption caused by mixed recovery treatment of refinery flare gas, the present invention provides a method for reducing the nitrogen content in flare gas recovery treatment, by increasing the branch line discharged to the nitrogen treatment system, carrying out targeted separate treatment, realizing effective quality-based recovery of flare gas, reducing energy consumption, improving combustion quality, and providing strong support for energy conservation, emission reduction and economic benefit improvement of refineries.
[0006] The purpose of the present invention is achieved through the following technical solutions: The present invention provides a method for reducing nitrogen content in flare gas recovery processing, comprising the following steps: (1) Add a branch line to the pipeline that feeds the regenerated nitrogen into the flare gas treatment system, and part of the regenerated nitrogen is fed into the nitrogen treatment system through the branch line; (2) The regenerated nitrogen introduced into the nitrogen treatment system is first pre-treated to adsorb heavy metals, and then mixed with compressed air to catalyze hydrocarbon combustion reaction; wherein the catalyst used for catalyzing hydrocarbon combustion is obtained by loading Ag and Pt catalytic active components on the carrier; (3) The mixed gas obtained after the reaction can be directly discharged after heat exchange and cooling.
[0007] The present invention adds a branch line for introducing the nitrogen treatment system to the pipeline for introducing the regenerated nitrogen into the flare gas treatment system, that is, the regenerated nitrogen originally introduced into the flare gas treatment system is separately treated, thereby reducing the system load and processing energy consumption. In addition, the nitrogen treatment system can carry out targeted treatment on the regenerated nitrogen, firstly adsorbing heavy metals through pretreatment, and then catalyzing hydrocarbon combustion reaction after mixing with compressed air. The catalyst used can have an efficient catalytic combustion effect on hydrocarbons, thereby realizing effective quality separation and recovery of the flare gas. The mixed gas obtained after the reaction can be directly discharged after heat exchange and cooling, thereby greatly reducing the economic cost and environmental pollution pressure caused by the flare gas combustion treatment, and improving the treatment efficiency.
[0008] Preferably, in step (1), the components of the regenerated nitrogen include nitrogen, heavy metals and hydrocarbons; and the temperature of the regenerated nitrogen is 250-300°C.
[0009] Preferably, in step (1), the regenerated nitrogen is: nitrogen is passed into the bed of the refiner to remove impurities therein so that the refiner can be reused, and the gas passed out is the regenerated nitrogen.
[0010] Preferably, in step (2), the adsorbent used in the adsorption pretreatment is activated carbon.
[0011] Preferably, in step (2), the pressure of the compressed air is 0.7-1.2 MPa and the temperature is room temperature.
[0012] Preferably, in step (2), the temperature of the catalytic hydrocarbon combustion reaction is 300-350°C.
[0013] Preferably, in step (2), the preparation of the catalyst comprises the following steps: dispersing the cellulose in water after loosening, adding sodium carboxymethyl cellulose and PAE wet strength agent and stirring and mixing, then adding pseudo-boehmite and ultrasonically mixing, then freezing and forming, and then freeze-drying; immersing the dried gel carrier in an aqueous solution containing silver nitrate and chloroplatinic acid in an ice water bath, then dropping a sodium borohydride aqueous solution and stirring; then filtering, drying, and roasting in an inert atmosphere to obtain the catalyst.
[0014] The catalyst uses cellulose gel as a carrier, and the Ag and Pt loaded thereon are catalytic active components, and the carbon skeleton formed by the cellulose gel carrier after calcination can also play a catalytic auxiliary role and adsorption role, which is conducive to the efficient catalytic combustion of hydrocarbons. In addition, the cellulose gel carrier is mainly composed of cellulose and sodium carboxymethyl cellulose, and the PAE wet strength agent is a cellulose cross-linking agent, thereby being able to form a catalyst carrier with a certain structural strength, and the PAE wet strength agent has a good adsorption effect on negative charges, so the sodium carboxymethyl cellulose doped part as the main body can improve the binding between components and improve the stability of the structure. The pseudo-boehmite added later will achieve good binding with sodium carboxymethyl cellulose due to its positive charge, improve the dispersibility and structural stability, and the addition of pseudo-boehmite to the carrier is also conducive to better loading of silver nitrate and chloroplatinic acid, and cooperates with the porosity of the gel carrier to provide more loading sites, and the loading dispersion and binding are also better. The alumina obtained by the pseudo-boehmite after calcination is embedded in the catalyst carrier, and can also cooperate with the Ag and Pt catalytic active components loaded thereon to achieve a better catalytic effect.
[0015] Preferably, the mass ratio of cellulose to water is 0.2-0.3:100; the added amounts of sodium carboxymethyl cellulose, PAE wet strength agent and pseudo-boehmite account for 50-60%, 30-35% and 30-40% of the mass of cellulose respectively.
[0016] Preferably, in the aqueous solution containing silver nitrate and chloroplatinic acid, the concentration of silver nitrate is 0.002-0.004 mmol / mL, and the concentration of chloroplatinic acid is 0.005-0.008 mmol / mL; the concentration of the sodium borohydride aqueous solution is 0.02-0.03 g / mL; the mass ratio of the gel carrier, the aqueous solution containing silver nitrate and chloroplatinic acid, and the sodium borohydride aqueous solution is 10 g:50 mL:10 mL; and the calcination is carried out at 500-600° C. in an inert gas atmosphere for 2-3 h.
[0017] Preferably, in step (3), the temperature of the mixed gas after heat exchange and cooling is 180° C. or below.
[0018] Compared with the prior art, the present invention has the following beneficial effects: (1) By adding a branch line to the nitrogen treatment system, targeted separate treatment is carried out to achieve effective quality recovery of flare gas, reduce energy consumption, improve combustion quality, and provide strong support for energy conservation, emission reduction and economic benefit improvement of the refinery; (2) The carbon skeleton formed by the cellulose gel carrier in the catalyst used for catalytic hydrocarbon combustion after calcination can play a catalytic auxiliary role and adsorption role. The alumina obtained after calcination of pseudo-boehmite is embedded in the carrier and can also cooperate with the Ag and Pt catalytic active components loaded on it. In addition, the dispersion of the catalytic components and the overall structural stability of the catalyst are both good, thereby being able to synergistically achieve an efficient catalytic effect. DETAILED DESCRIPTION
[0019] The technical solution of the present invention is described below with specific embodiments, but the protection scope of the present invention is not limited thereto.
[0020] A method for reducing nitrogen content in flare gas recovery processing comprises the following steps: (1) Nitrogen is passed into the bed of the refiner to remove impurities so that the refiner can be reused. The gas passed out is regenerated nitrogen. The components of regenerated nitrogen include nitrogen, heavy metals and hydrocarbons, and the temperature is 250-300℃.
[0021] (2) A branch is added to the pipeline for introducing the regenerated nitrogen into the flare gas treatment system, and part of the regenerated nitrogen is introduced into the nitrogen treatment system through the branch. The nitrogen treatment system includes a pretreatment adsorption tank, a regenerated gas heat exchanger and a reactor connected in sequence.
[0022] (3) The regenerated nitrogen introduced into the nitrogen treatment system is first introduced into the pretreatment adsorption tank for pretreatment, and the heavy metals are adsorbed by the adsorbent activated carbon in the pretreatment adsorption tank. The regenerated gas from the pretreatment adsorption tank is mixed with compressed air, the pressure of the compressed air is 0.7-1.2MPa, and the temperature is room temperature. After mixing, it is introduced into the regenerated gas heat exchanger for heat exchange and temperature rise to 300-350℃, and then introduced into the reactor for catalytic hydrocarbon combustion reaction by catalyst catalysis, and the reaction temperature is 300-350℃.
[0023] The preparation of the catalyst comprises the following steps: after loosening the cellulose, the cellulose is dispersed in water at a mass ratio of 0.2 to 0.3:100, sodium carboxymethyl cellulose accounting for 50 to 60% of the mass of the cellulose and PAE wet strength agent accounting for 30 to 35% of the mass of the cellulose are added and stirred and mixed, after uniform mixing, pseudo-boehmite accounting for 30 to 40% of the mass of the cellulose is added and ultrasonically mixed, then frozen and formed, and freeze-dried after forming. In an ice water bath, the dried gel carrier is immersed in an aqueous solution containing 0.002 to 0.004 mmol / mL silver nitrate and 0.005 to 0.008 mmol / mL chloroplatinic acid, and then a sodium borohydride aqueous solution with a concentration of 0.02 to 0.03 g / mL is added dropwise and stirred, wherein the mass ratio of the gel carrier, the aqueous solution containing silver nitrate and chloroplatinic acid, and the sodium borohydride aqueous solution is 10 g: 50 mL: 10 mL. Next, after filtering and drying, the product is calcined at 500-600° C. in an inert gas atmosphere for 2-3 hours to obtain a catalyst.
[0024] (4) The mixed gas obtained after the reaction can be directly discharged into the atmosphere through a chimney after being cooled to 180°C or below by heat exchange.
[0025] In a specific embodiment of the present invention, the refiner is a desulfurization reactor of a C1C2 separation device, and the regenerated nitrogen contains nitrogen, 0-80% ethylene gas, 0-20% ethane gas and 5-50 mg·kg of heavy metal arsenic. -1 .
[0026] In a specific embodiment of the present invention, when the treatment starts, the hydrocarbon content in the refiner is relatively high, and the regenerated nitrogen is discharged to the flare gas treatment system for recovery; thereafter, when the volume content of hydrocarbon gases (ethylene gas and ethane gas) in the regenerated nitrogen is 5±3%, the regenerated gas nitrogen exhaust treatment system control valve is opened, and at the same time, the regenerated nitrogen flare control valve is gradually closed, that is, the regenerated nitrogen is discharged to the nitrogen treatment system for treatment during subsequent treatment.
[0027] In a specific embodiment of the present invention, the loading amount of activated carbon in the pretreatment adsorption tank is 70-80% (1.5-2.5 m 3 ), the catalyst loading in the reactor is 70-80% of its volume (2.8-3.4m 3 ).
[0028] In a specific embodiment of the present invention, the loosening treatment of cellulose includes: placing the cellulose in a reaction kettle, heating the kettle temperature to 90-95°C, and increasing the kettle pressure to 2-2.5MPa, treating for 20-30 minutes, and then immediately and quickly releasing the temperature and pressure to normal temperature and pressure.
[0029] In a specific embodiment of the present invention, the PAE wet strength agent is a polyamide polyepichlorohydrin resin, and the active ingredient content is 12.5±0.5%.
[0030] In a specific embodiment of the present invention, the particle size of the pseudo-boehmite is 10 to 20 μm.
[0031] Example 1 (1) Nitrogen is passed into the bed of the refiner to remove impurities so that the refiner can be reused. The gas passed out is regenerated nitrogen. The components of the regenerated nitrogen include nitrogen, heavy metals and hydrocarbons, and the temperature is 250°C.
[0032] (2) A branch is added to the pipeline that feeds the regenerated nitrogen into the flare gas treatment system, and part of the regenerated nitrogen is fed into the nitrogen treatment system through the branch. At the beginning of the treatment, the hydrocarbon content in the refiner is high, and it is discharged to the flare gas treatment system for recovery. Then, the control valve of the regenerated gas discharge nitrogen treatment system is opened, and the regenerated nitrogen discharge flare control valve is gradually closed at the same time, that is, the regenerated nitrogen is discharged to the nitrogen treatment system for treatment during subsequent treatment.
[0033] (3) The regenerated nitrogen introduced into the nitrogen treatment system is first introduced into the pretreatment adsorption tank for pretreatment, and the heavy metals are adsorbed by the adsorbent (activated carbon) in the pretreatment adsorption tank. The regenerated gas from the pretreatment adsorption tank is mixed with compressed air, the pressure of the compressed air is 0.7MPa, and the temperature is room temperature. After mixing, it is introduced into the regeneration gas heat exchanger for heat exchange and temperature rise to 300℃, and then introduced into the reactor for catalytic hydrocarbon combustion reaction by catalyst catalysis, and the reaction temperature is 300℃.
[0034] The preparation of the catalyst comprises the following steps: (a) Cellulose is placed in a reaction kettle, heated to 90°C, and the pressure in the kettle is increased to 2.5 MPa. After treating for 25 minutes, the temperature and pressure are immediately and rapidly released to normal temperature and pressure.
[0035] (b) The loosened cellulose is dispersed in water at a mass ratio of 0.26:100, and sodium carboxymethyl cellulose accounting for 55% of the mass of cellulose and PAE wet strength agent accounting for 35% of the mass of cellulose are added and stirred and mixed. After uniform mixing, pseudo-boehmite accounting for 33% of the mass of cellulose is added and ultrasonically mixed, and then frozen and formed. After forming, freeze-dried. In an ice water bath, 100g of the dried gel carrier is immersed in 500mL of an aqueous solution containing 0.004mmol / mL silver nitrate and 0.005mmol / mL chloroplatinic acid, and then 100mL of a sodium borohydride aqueous solution with a concentration of 0.02g / mL is added dropwise and stirred. Then, after filtering and drying, the temperature is raised to 600℃ at a rate of 2℃ / min, and the catalyst is obtained by calcining for 2h under a nitrogen atmosphere.
[0036] (4) The mixed gas obtained after the reaction is cooled to 180°C by heat exchange and can be directly discharged into the atmosphere through a chimney.
[0037] Example 2 The difference from Example 1 is that the preparation method of the catalyst is different.
[0038] (1) Nitrogen is passed into the bed of the refiner to remove impurities so that the refiner can be reused. The gas passed out is regenerated nitrogen. The components of the regenerated nitrogen include nitrogen, heavy metals and hydrocarbons, and the temperature is 250°C.
[0039] (2) A branch is added to the pipeline that feeds the regenerated nitrogen into the flare gas treatment system, and part of the regenerated nitrogen is fed into the nitrogen treatment system through the branch. At the beginning of the treatment, the hydrocarbon content in the refiner is high, and it is discharged to the flare gas treatment system for recovery. Then, the control valve of the regenerated gas discharge nitrogen treatment system is opened, and the regenerated nitrogen discharge flare control valve is gradually closed at the same time, that is, the regenerated nitrogen is discharged to the nitrogen treatment system for treatment during subsequent treatment.
[0040] (3) The regenerated nitrogen introduced into the nitrogen treatment system is first introduced into the pretreatment adsorption tank for pretreatment, and the heavy metals are adsorbed by the adsorbent (activated carbon) in the pretreatment adsorption tank. The regenerated gas from the pretreatment adsorption tank is mixed with compressed air, the pressure of the compressed air is 0.7MPa, and the temperature is room temperature. After mixing, it is introduced into the regeneration gas heat exchanger for heat exchange and temperature rise to 300℃, and then introduced into the reactor for catalytic hydrocarbon combustion reaction by catalyst catalysis, and the reaction temperature is 300℃.
[0041] The preparation of the catalyst comprises the following steps: (a) Cellulose is placed in a reaction kettle, heated to 90°C, and the pressure in the kettle is increased to 2.5 MPa. After treating for 25 minutes, the temperature and pressure are immediately and rapidly released to normal temperature and pressure.
[0042] (b) The loosened cellulose is dispersed in water at a mass ratio of 0.2:100, and sodium carboxymethyl cellulose accounting for 60% of the mass of cellulose and PAE wet strength agent accounting for 35% of the mass of cellulose are added and stirred and mixed. After uniform mixing, pseudo-boehmite accounting for 30% of the mass of cellulose is added and ultrasonically mixed, and then frozen and formed. After forming, freeze-dried. In an ice water bath, 100g of the dried gel carrier is immersed in 500mL of an aqueous solution containing 0.002mmol / mL silver nitrate and 0.008mmol / mL chloroplatinic acid, and then 100mL of a sodium borohydride aqueous solution with a concentration of 0.03g / mL is added dropwise and stirred. Then, after filtering and drying, the temperature is raised to 600℃ at a rate of 2℃ / min, and the catalyst is obtained by calcining for 2h under a nitrogen atmosphere.
[0043] (4) The mixed gas obtained after the reaction is cooled to 180°C by heat exchange and can be directly discharged into the atmosphere through a chimney.
[0044] Example 3 The difference from Example 1 is that the preparation method of the catalyst is different.
[0045] (1) Nitrogen is passed into the bed of the refiner to remove impurities so that the refiner can be reused. The gas passed out is regenerated nitrogen. The components of the regenerated nitrogen include nitrogen, heavy metals and hydrocarbons, and the temperature is 250°C.
[0046] (2) A branch is added to the pipeline that feeds the regenerated nitrogen into the flare gas treatment system, and part of the regenerated nitrogen is fed into the nitrogen treatment system through the branch. At the beginning of the treatment, the hydrocarbon content in the refiner is high, and it is discharged to the flare gas treatment system for recovery. Then, the control valve of the regenerated gas discharge nitrogen treatment system is opened, and the regenerated nitrogen discharge flare control valve is gradually closed at the same time, that is, the regenerated nitrogen is discharged to the nitrogen treatment system for treatment during subsequent treatment.
[0047] (3) The regenerated nitrogen introduced into the nitrogen treatment system is first introduced into the pretreatment adsorption tank for pretreatment, and the heavy metals are adsorbed by the adsorbent (activated carbon) in the pretreatment adsorption tank. The regenerated gas from the pretreatment adsorption tank is mixed with compressed air, the pressure of the compressed air is 0.7MPa, and the temperature is room temperature. After mixing, it is introduced into the regeneration gas heat exchanger for heat exchange and temperature rise to 300℃, and then introduced into the reactor for catalytic hydrocarbon combustion reaction by catalyst catalysis, and the reaction temperature is 300℃.
[0048] The preparation of the catalyst comprises the following steps: (a) Cellulose is placed in a reaction kettle, heated to 90°C, and the pressure in the kettle is increased to 2.5 MPa. After treating for 25 minutes, the temperature and pressure are immediately and rapidly released to normal temperature and pressure.
[0049] (b) The loosened cellulose is dispersed in water at a mass ratio of 0.3:100, and sodium carboxymethyl cellulose accounting for 50% of the mass of cellulose and PAE wet strength agent accounting for 30% of the mass of cellulose are added and stirred and mixed. After uniform mixing, pseudo-boehmite accounting for 40% of the mass of cellulose is added and ultrasonically mixed, and then frozen and formed. After forming, freeze-dried. In an ice water bath, 100g of the dried gel carrier is immersed in 500mL of an aqueous solution containing 0.004mmol / mL silver nitrate and 0.005mmol / mL chloroplatinic acid, and then 100mL of a sodium borohydride aqueous solution with a concentration of 0.03g / mL is added dropwise and stirred. Then, after filtering and drying, the temperature is raised to 600℃ at a rate of 2℃ / min, and the catalyst is obtained by calcining for 2h under a nitrogen atmosphere.
[0050] (4) The mixed gas obtained after the reaction is cooled to 180°C by heat exchange and can be directly discharged into the atmosphere through a chimney.
[0051] Comparative Example 1 The difference between the preparation of the catalyst and Example 1 is that no sodium carboxymethyl cellulose is added.
[0052] The preparation of the catalyst comprises the following steps: (a) Cellulose is placed in a reaction kettle, heated to 90°C, and the pressure in the kettle is increased to 2.5 MPa. After treating for 25 minutes, the temperature and pressure are immediately and rapidly released to normal temperature and pressure.
[0053] (b) The loosened cellulose is dispersed in water at a mass ratio of 0.403:100, and a PAE wet strength agent accounting for 35% of the mass of the cellulose is added and stirred and mixed. After uniform mixing, a pseudo-boehmite accounting for 33% of the mass of the cellulose is added and ultrasonically mixed, and then frozen and formed. After forming, freeze-dried. In an ice water bath, 100g of the dried gel carrier is immersed in 500mL of an aqueous solution containing 0.004mmol / mL silver nitrate and 0.005mmol / mL chloroplatinic acid, and then 100mL of a sodium borohydride aqueous solution with a concentration of 0.02g / mL is added dropwise and stirred. Then, after filtering and drying, the temperature is raised to 600℃ at a rate of 2℃ / min, and the catalyst is obtained by calcining for 2h under a nitrogen atmosphere.
[0054] Comparative Example 2 The difference between the preparation of the catalyst and Example 1 is that the amount of sodium carboxymethyl cellulose added is too small.
[0055] The preparation of the catalyst comprises the following steps: (a) Cellulose is placed in a reaction kettle, heated to 90°C, and the pressure in the kettle is increased to 2.5 MPa. After treating for 25 minutes, the temperature and pressure are immediately and rapidly released to normal temperature and pressure.
[0056] (b) The loosened cellulose is dispersed in water at a mass ratio of 0.338:100, and sodium carboxymethyl cellulose accounting for 25% of the mass of cellulose and PAE wet strength agent accounting for 35% of the mass of cellulose are added and stirred and mixed. After uniform mixing, pseudo-boehmite accounting for 33% of the mass of cellulose is added and ultrasonically mixed, and then frozen and formed. After forming, freeze-dried. In an ice water bath, 100g of the dried gel carrier is immersed in 500mL of an aqueous solution containing 0.004mmol / mL silver nitrate and 0.005mmol / mL chloroplatinic acid, and then 100mL of a sodium borohydride aqueous solution with a concentration of 0.02g / mL is added dropwise and stirred. Then, after filtering and drying, the temperature is raised to 600℃ at a rate of 2℃ / min, and the catalyst is obtained by calcining for 2h under a nitrogen atmosphere.
[0057] Comparative Example 3 The preparation of the catalyst differs from that of Example 1 in that no pseudo-boehmite is added.
[0058] The preparation of the catalyst comprises the following steps: (a) Cellulose is placed in a reaction kettle, heated to 90°C, and the pressure in the kettle is increased to 2.5 MPa. After treating for 25 minutes, the temperature and pressure are immediately and rapidly released to normal temperature and pressure.
[0059] (b) The loosened cellulose is dispersed in water at a mass ratio of 0.26:100, and sodium carboxymethyl cellulose accounting for 55% of the mass of the cellulose and PAE wet strength agent accounting for 35% of the mass of the cellulose are added and stirred and mixed. After uniform mixing, the mixture is frozen and formed, and then freeze-dried. In an ice water bath, 100 g of the dried gel carrier is immersed in 500 mL of an aqueous solution containing 0.004 mmol / mL silver nitrate and 0.005 mmol / mL chloroplatinic acid, and then 100 mL of a sodium borohydride aqueous solution with a concentration of 0.02 g / mL is added dropwise and stirred. Then, after filtering and drying, the mixture is heated to 600°C at a rate of 2°C / min and calcined for 2 hours under a nitrogen atmosphere to obtain a catalyst.
[0060] Comparative Example 4 The difference between the preparation of the catalyst and that of Example 1 is that no silver nitrate is added.
[0061] The preparation of the catalyst comprises the following steps: (a) Cellulose is placed in a reaction kettle, heated to 90°C, and the pressure in the kettle is increased to 2.5 MPa. After treating for 25 minutes, the temperature and pressure are immediately and rapidly released to normal temperature and pressure.
[0062] (b) The loosened cellulose is dispersed in water at a mass ratio of 0.26:100, and sodium carboxymethyl cellulose accounting for 55% of the mass of cellulose and PAE wet strength agent accounting for 35% of the mass of cellulose are added and stirred and mixed. After uniform mixing, pseudo-boehmite accounting for 33% of the mass of cellulose is added and ultrasonically mixed, and then frozen and formed. After forming, freeze-dried. In an ice water bath, 100g of the dried gel carrier is immersed in 500mL of an aqueous solution containing 0.009mmol / mL chloroplatinic acid, and then 100mL of a sodium borohydride aqueous solution with a concentration of 0.02g / mL is added dropwise and stirred. Then, after filtering and drying, the temperature is raised to 600℃ at a rate of 2℃ / min, and the catalyst is obtained by calcining for 2h under a nitrogen atmosphere.
[0063] The regenerated nitrogen gas introduced into the nitrogen treatment system in Examples 1-3 and Comparative Examples 1-4 is the same as the regenerated nitrogen gas of the same composition, and the same volume of regenerated nitrogen gas (4000 Nm 3 / h), the components of the mixed gas obtained after being treated by the nitrogen treatment system in each embodiment and each comparative example were detected, and the results are shown in Table 1.
[0064] Table 1 By using the present invention, the amount of nitrogen entering the flare gas pipeline network can be effectively reduced, thereby reducing the energy consumption of the flare gas recovery compressor and the nitrogen content of the fuel gas pipeline network. Specifically, the refiner (desulfurization reactor of the C1C2 separation device) in Example 1 is designed to have a regeneration cycle of 7 days, a regeneration time of 72 hours, and a regeneration flow rate of 4000Nm 3 / h. In the past, the regeneration nitrogen was 4000Nm 3 / h enters the flare gas network, making 30000Nm 3 / h flare gas system nitrogen content increased by 11.76%, the flare gas recovery compressor load increased, the fuel gas calorific value decreased, a total of about 4000*72=288000Nm 3 After the technical solution described in Example 1, the time for the regenerated gas to be discharged into the flare system was reduced to 5 hours, and the total amount of regenerated nitrogen discharged into the flare gas treatment system was reduced to 20,000 Nm 3 , reduced by 93%. The purpose of reducing energy consumption, improving combustion quality, saving energy and reducing emissions, and improving economic benefits has been achieved.
[0065] In addition, as shown in Table 1, the catalyst prepared in the present invention is used in the reactor to catalyze the hydrocarbon combustion reaction, and the catalytic synergistic effect is better, and the hydrocarbon combustion reaction can be effectively catalyzed, and the mixed gas obtained by the reaction meets the emission standards. Comparative Examples 1-4 show that the raw material components added during the preparation of the catalyst will affect the catalytic active components loaded on the catalyst, and the catalytic active components on the catalyst of the present invention can synergistically achieve a better catalytic effect, and the added sodium carboxymethyl cellulose helps to improve the binding between the components and improve the stability of the structure, so that the content of the effective catalytic components contained in the catalyst is higher, and the catalytic effect is better.
[0066] The above are only preferred embodiments of the present invention, and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the specification of the present invention, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.
Claims
1. A method for reducing nitrogen content in flare gas recovery treatment, characterized in that: The steps include: (1) Add a branch line to the pipeline that feeds the regenerated nitrogen into the flare gas treatment system, and part of the regenerated nitrogen is fed into the nitrogen treatment system through the branch line; (2) The regenerated nitrogen introduced into the nitrogen treatment system is first pre-treated to adsorb heavy metals, and then mixed with compressed air to catalyze hydrocarbon combustion reaction; wherein the catalyst used for catalyzing hydrocarbon combustion is obtained by loading Ag and Pt catalytic active components on the carrier; (3) The mixed gas obtained after the reaction can be directly discharged after heat exchange and cooling.
2. The method for reducing nitrogen content in flare gas recovery process according to claim 1, characterized in that: In step (1), the components of the regenerated nitrogen include nitrogen, heavy metals and hydrocarbons; and the temperature of the regenerated nitrogen is 250-300°C.
3. The method for reducing nitrogen content in flare gas recovery process according to claim 1 or 2, characterized in that: In step (1), the regenerated nitrogen is: nitrogen is passed into the bed of the refiner to remove impurities therein so that the refiner can be reused, and the gas passed out is the regenerated nitrogen.
4. The method for reducing nitrogen content in flare gas recovery process according to claim 1, characterized in that: In step (2), the adsorbent used in the adsorption pretreatment is activated carbon.
5. The method for reducing nitrogen content in flare gas recovery process according to claim 1, characterized in that: In step (2), the pressure of the compressed air is 0.7-1.2 MPa and the temperature is room temperature.
6. The method for reducing nitrogen content in flare gas recovery process according to claim 1, 4 or 5, characterized in that: In step (2), the temperature of the catalytic hydrocarbon combustion reaction is 300-350°C.
7. The method for reducing nitrogen content in flare gas recovery process according to claim 1, characterized in that: In step (2), the preparation of the catalyst comprises the following steps: dispersing the cellulose in water after loosening, adding sodium carboxymethyl cellulose and PAE wet strength agent and stirring and mixing, then adding pseudo-boehmite and ultrasonically mixing, then freezing and forming, and then freeze-drying; immersing the dried gel carrier in an aqueous solution containing silver nitrate and chloroplatinic acid in an ice water bath, then dropping a sodium borohydride aqueous solution and stirring; then filtering, drying, and roasting in an inert atmosphere to obtain a catalyst.
8. The method for reducing nitrogen content in flare gas recovery treatment according to claim 7, characterized in that: The mass ratio of cellulose to water is 0.2-0.3:100; the added amounts of sodium carboxymethyl cellulose, PAE wet strength agent and pseudo-boehmite account for 50-60%, 30-35% and 30-40% of the mass of cellulose respectively.
9. The method for reducing nitrogen content in flare gas recovery process according to claim 7 or 8, characterized in that: In the aqueous solution containing silver nitrate and chloroplatinic acid, the concentration of silver nitrate is 0.002-0.004 mmol / mL, and the concentration of chloroplatinic acid is 0.005-0.008 mmol / mL; the concentration of the sodium borohydride aqueous solution is 0.02-0.03 g / mL; the mass ratio of the gel carrier, the aqueous solution containing silver nitrate and chloroplatinic acid, and the sodium borohydride aqueous solution is 10 g:50 mL:10 mL; and the calcination is performed at 500-600° C. for 2-3 hours.
10. The method for reducing nitrogen content in flare gas recovery treatment according to claim 1, characterized in that: In step (3), the temperature of the mixed gas after heat exchange and cooling is 180° C. or less.