System for preparing concentrated sulfuric acid through dilute sulfuric acid regeneration of alkylation device

Abstract

The utility model discloses a system for preparing concentrated sulfuric acid by regenerating dilute sulfuric acid of an alkylation device. The system comprises a raw material pretreatment unit, an incineration conversion unit, a product purification and absorption unit and a tail gas treatment unit, the raw material pretreatment unit is used for carrying out drying, liquid separation, mixing and preheating on used air, hydrogen sulfide and dilute sulfuric acid raw material gas and then conveying the raw material gas to the incineration conversion unit; the incineration conversion unit is used for converting hydrogen sulfide and dilute sulphuric acid into sulfur trioxide gas under the action of oxygen-enriched air and a catalyst, and the sulfur trioxide gas generated by the incineration conversion unit enters the purification and absorption unit; the product purification and absorption adopts concentrated sulfuric acid to absorb sulfur trioxide gas to generate a concentrated sulfuric acid product, and acid-containing tail gas generated by purification and absorption enters a tail gas treatment unit to be treated. According to the device, co-combustion of hydrogen sulfide and dilute sulfuric acid in the incinerator is achieved, concentrated sulfuric acid with high concentration is obtained through subsequent conversion, purification, absorption and tail gas treatment, and cyclic regeneration of sulfuric acid is achieved.

Description

TECHNICAL FIELD

[0001] The utility model belongs to the technical field of dilute sulfuric acid regeneration concentration, specifically relates to a kind of system of dilute sulfuric acid regeneration preparation concentrated sulfuric acid of alkylating unit. BACKGROUND

[0002] As the main process technology for producing high-grade, high-octane clean gasoline, sulfuric acid alkylation produces a large amount of waste dilute sulfuric acid in the production process. It is very difficult to treat due to its containing organic matter, impurities and water and other components. At present, the burning cracking process is generally used to produce SO2 flue gas, which is treated by purification, drying, conversion, absorption and other processes to increase the concentration of sulfuric acid. However, due to the imbalance of water produced during the combustion of organic matter, the concentration of sulfuric acid is limited, and it is difficult to recycle.

[0003] In the prior art, CN111747382 proposes a method and system for dilute acid concentration recovery using an alkylated waste acid recovery device, comprising the following steps: the cracking furnace gas is sent to the dynamic wave washing tower for purification after waste heat recovery, SO3 in the furnace gas is absorbed by the dynamic wave circulating liquid to form dilute acid, part of the water vapor is cooled and condensed by the dynamic wave washing tower, and the uncondensed part of the water vapor enters the mist removal device after the gas enters the mist removal device to remove the liquid mist and sulfuric acid mist in the gas, and then is sent to the packing tower for further cooling. The water vapor in the gas is condensed into liquid water in the packing tower and discharged to the degassing tower. The liquid water after removing SO2 in the degassing tower is discharged to the tail gas washing tower, and the SO2 gas after removal is discharged to the drying tower for recycling. The dilute sulfuric acid at the bottom of the mist removal device is discharged to the dynamic wave washing tower. The invention obtains dilute sulfuric acid by absorption in the dynamic wave washing tower, and then concentrates and concentrates. There are problems of long concentration process and high energy consumption. SUMMARY

[0004] In order to overcome the defects of the above prior art, the purpose of the utility model is to provide a system for dilute sulfuric acid regeneration and preparation of concentrated sulfuric acid in alkylating unit. By introducing hydrogen sulfide gas produced in refinery during dilute sulfuric acid incineration, hydrogen sulfide and dilute sulfuric acid are co-combusted in the incinerator. Through subsequent conversion, purification, absorption and tail gas treatment, high-concentration concentrated sulfuric acid is obtained, the sulfuric acid is recycled, and the process is short, the energy consumption is low, and the sulfuric acid utilization rate is high.

[0005] In order to achieve the above purpose, the technical scheme adopted by the utility model is:

[0006] A system for dilute sulfuric acid regeneration and preparation of concentrated sulfuric acid in alkylating unit, the system comprising a raw material pretreatment unit, a burning conversion unit, a product purification and absorption unit, and a tail gas treatment unit;

[0007] The raw material pretreatment unit is used to dry, separate, mix and preheat the used air, hydrogen sulfide and dilute sulfuric acid raw gas, and then deliver them to the burning conversion unit;

[0008] The incineration conversion unit is used for converting hydrogen sulfide and dilute sulfuric acid into sulfur trioxide gas under the action of oxygen-rich air and a catalyst, and the sulfur trioxide gas generated by the incineration conversion unit enters the purification absorption unit;

[0009] The product purification absorption uses concentrated sulfuric acid to absorb sulfur trioxide gas to generate a concentrated sulfuric acid product, and the acid-containing tail gas generated by the purification absorption enters the tail gas treatment unit for treatment.

[0010] The raw material pretreatment unit comprises an air filter 1, a dryer one 2, a hydrogen sulfide buffer tank 3, a gas-liquid separation tank 4, a dilute sulfuric acid tank 5, a static mixer 6, and a preheater 7.

[0011] The gas output end of the air filter 1 is communicated with the static mixer 6 through the dryer one 2.

[0012] The output end of the hydrogen sulfide buffer tank 3 is communicated with the static mixer 6 through the gas-liquid separation tank 4.

[0013] The output end of the dilute sulfuric acid tank 5 is connected with the static mixer 6, and the output end of the static mixer 6 is connected with the preheater 7.

[0014] The incineration conversion unit comprises an incinerator 8, a waste heat boiler 9, and a converter 10, and the output end of the preheater 7 is sequentially connected with the incinerator 8, the waste heat boiler 9, and the converter 10.

[0015] The product purification absorption unit comprises a washing and purification tower 11, a dryer two 12, an absorption tower 13, a sulfuric acid tank 14, and a sulfuric acid circulating pump 15.

[0016] The output end of the washing and purification tower 11 is connected with the input end of the dryer two 12, the output end of the dryer two 12 is connected with the input end of the absorption tower 13, and the output end of the absorption tower 13 is connected with the sulfuric acid tank 14.

[0017] The bottom output end of the washing and purification tower 11 is connected with the input end of the dilute sulfuric acid tank 5 through a pipeline, and the bottom output end of the dilute sulfuric acid tank 5 is connected with the upper side of the washing and purification tower 11 through a pipeline to form a circulation.

[0018] The outlet of the sulfuric acid tank 14 is connected to the upper side of the washing and purification tower 11 through the sulfuric acid circulating pump 15.

[0019] The tail gas treatment unit comprises a caustic washing tower 16, a lye tank 17, a lye pump 18, and a distributor 19.

[0020] The input end of the caustic washing tower 16 is connected with the output end of the top of the absorption tower 13, the bottom output end of the caustic washing tower 16 is connected with the lye tank 17, and the output end of the lye tank 17 is connected to the distributor 19 in the caustic washing tower 16 through the lye pump 18,

[0021] The distributor 19 is located at the upper end inside the caustic washing tower 16.

[0022] The air filter 1 is used for purifying air in the atmosphere and removing impurities in the air.

[0023] The utility model discloses beneficial effect:

[0024] On the basis of traditional dilute sulfuric acid concentration process, introduce refinery byproduct hydrogen sulfide as incinerator raw material gas and dilute sulfuric acid to carry out co-incineration conversion at the raw material end, improve sulfuric acid concentration through static mixer mixing, not only realize resource complementation and energy interuse, but also promote the cyclic regeneration of waste dilute sulfuric acid, reduce the environmental pollution problem brought by waste dilute sulfuric acid. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 It is system connection schematic diagram of the utility model.

[0026] In the drawing: 1-air filter;2-dryer;3-hydrogen sulfide buffer tank;4-gas-liquid separation tank;5-dilute sulfuric acid tank;6-static mixer;7-preheater;8-incinerator;9-converter;10-exhaust-heat boiler;11-washing and purifying tower;12-dryer;13-absorption tower;14-sulfuric acid tank;15-sulfuric acid circulating pump;16-caustic washing tower;17-caustic solution tank;18-caustic solution pump;19-distributor. DETAILED DESCRIPTION

[0027] The utility model will be further explained in detail in connection with the drawings.

[0028] As Figure 1 Indicated, a kind of alkylating unit dilute sulfuric acid regeneration system for preparing concentrated sulfuric acid, the system includes raw material pretreatment unit, incineration conversion unit, product purification absorption unit and tail gas treatment unit;

[0029] The raw material pretreatment unit is used to dry, separate, mix and preheat the used air, hydrogen sulfide and dilute sulfuric acid raw gas, and then deliver to the incineration conversion unit;

[0030] The incineration conversion unit is used to convert hydrogen sulfide and dilute sulfuric acid into sulfur trioxide gas under the action of oxygen-rich air and catalyst, and the sulfur trioxide gas generated by the incineration conversion unit enters the purification absorption unit.

[0031] The product purification absorption uses concentrated sulfuric acid to absorb sulfur trioxide gas, generates concentrated sulfuric acid product, and the acid-containing tail gas generated by purification absorption enters the tail gas treatment unit for treatment.

[0032] The raw material pretreatment unit includes air filter 1, dryer one 2, hydrogen sulfide buffer tank 3, gas-liquid separation tank 4, dilute sulfuric acid tank 5, static mixer 6 and preheater 7.

[0033] The gas output end of the air filter 1 is communicated with the static mixer 6 through the drier 2;

[0034] The output end of the hydrogen sulfide buffer tank 3 is communicated with the static mixer 6 through the gas-liquid separation tank 4;

[0035] The output end of the dilute sulfuric acid tank 5 is connected with the static mixer 6, and the output end of the static mixer 6 is connected with the preheater 7.

[0036] The incineration conversion unit comprises an incinerator 8, a waste heat boiler 9 and a converter 10, and the output end of the preheater 7 is sequentially connected with the incinerator 8, the waste heat boiler 9 and the converter 10.

[0037] The product purification and absorption unit comprises a washing and purification tower 11, a drier 12, an absorption tower 13, a sulfuric acid tank 14 and a sulfuric acid circulating pump 15.

[0038] The output end of the washing and purification tower 11 is connected with the input end of the drier 12, the output end of the drier 12 is connected with the input end of the absorption tower 13, and the output end of the absorption tower 13 is connected with the sulfuric acid tank 14.

[0039] The bottom output end of the washing and purification tower 11 is connected with the input end of the dilute sulfuric acid tank 5 through a pipeline, and the bottom output end of the dilute sulfuric acid tank 5 is connected with the upper side of the washing and purification tower 11 through a pipeline, so as to form a circulation.

[0040] The outlet of the sulfuric acid tank 14 is connected with the upper side of the washing and purification tower 11 through the sulfuric acid circulating pump 15.

[0041] The tail gas treatment unit comprises an alkali washing tower 16, an alkali tank 17, an alkali pump 18 and a distributor 19.

[0042] The input end of the alkali washing tower 16 is connected with the output end of the top of the absorption tower 13, the bottom output end of the alkali washing tower 16 is connected with the alkali tank 17, and the output end of the alkali tank 17 is connected with the distributor 19 in the alkali washing tower 16 through the alkali pump 18.

[0043] The distributor 19 is located at the upper end in the alkali washing tower 16.

[0044] The air filter 1 is used for purifying and treating the air in the atmosphere and removing impurities in the air.

[0045] The working principle of the utility model:

[0046] Figure 1As shown, the air is sequentially treated by the air filter 1 and the dryer 2, then uniformly mixed with hydrogen sulfide and dilute sulfuric acid in the static mixer 6, preheated by the preheater 7, and sprayed into the incinerator 8 to generate SO2 and H2O under high temperature conditions, converted into SO3 by the converter 9, enters the waste heat boiler 10 to recover high-grade heat energy, and the temperature is reduced to 150-270℃, then enters the washing and purification tower 11, removes impurities and dust in the mixed gas by dilute sulfuric acid washing, dried by the dryer 2, enters the absorption tower, and the absorption tower 13 uses 98% concentrated sulfuric acid for absorption, and the obtained high-concentration sulfuric acid product is partially discharged from the device, and the gas treated by purification and absorption enters the alkali washing tower 16 to recover and treat the remaining SO3 in the gas, and the tail gas can be vented through the chimney.

[0047] The raw material hydrogen sulfide is derived from one or more mixtures of heavy oil hydrocracking, gasoline hydrogenation and diesel hydrogenation refining devices, and its concentration is 5%-99.5wt%.

[0048] The raw material dilute sulfuric acid is derived from waste dilute sulfuric acid produced by a sulfuric acid alkylation device, and its concentration is 80%-91%.

[0049] The temperature of the incinerator 8 is controlled at 1050-1300℃, and the furnace gas is reduced to 150-270℃ after the waste heat boiler 9. The absorption tower 12 uses 98% concentrated sulfuric acid for absorption and concentration to obtain a high-concentration sulfuric acid product, a part of which enters the sulfuric acid product tank area, and a part of which is recycled into the alkylation device for use.

Claims

1. A system for producing concentrated sulfuric acid from dilute sulfuric acid regenerated in an alkylation unit, characterized by, The system comprises a raw material pretreatment unit, a burning conversion unit, a product purification and absorption unit and a tail gas treatment unit; The raw material pretreatment unit is used for drying, separating, mixing and preheating the used air, hydrogen sulfide and dilute sulfuric acid raw gas, and then delivering the gas to the burning conversion unit; The burning conversion unit is used for converting hydrogen sulfide and dilute sulfuric acid into sulfur trioxide gas under the action of oxygen-rich air and a catalyst, and the sulfur trioxide gas generated by the burning conversion unit enters the purification and absorption unit; The product purification and absorption unit absorbs the sulfur trioxide gas with concentrated sulfuric acid to generate concentrated sulfuric acid products, and the acid-containing tail gas generated by the purification and absorption enters the tail gas treatment unit for treatment; The raw material pretreatment unit comprises an air filter (1), a dryer I (2), a hydrogen sulfide buffer tank (3), a gas-liquid separation tank (4), a dilute sulfuric acid tank (5), a static mixer (6) and a preheater (7); The gas output end of the air filter (1) is communicated with the static mixer (6) through the dryer I (2); The output end of the hydrogen sulfide buffer tank (3) is communicated with the static mixer (6) through the gas-liquid separation tank (4); The output end of the dilute sulfuric acid tank (5) is connected with the static mixer (6), and the output end of the static mixer (6) is connected with the preheater (7); The burning conversion unit comprises a burning furnace (8), a waste heat boiler (9) and a converter (10), and the output end of the preheater (7) is sequentially connected with the burning furnace (8), the waste heat boiler (9) and the converter (10); The product purification and absorption unit comprises a washing and purification tower (11), a dryer II (12), an absorption tower (13), a sulfuric acid storage tank (14) and a sulfuric acid circulating pump (15); The output end of the washing and purification tower (11) is connected with the input end of the dryer II (12), the output end of the dryer II (12) is connected with the input end of the absorption tower (13), and the output end of the absorption tower (13) is connected with the sulfuric acid storage tank (14); The bottom output end of the washing and purification tower (11) is connected with the input end of the dilute sulfuric acid tank (5) through a pipeline, and the bottom output end of the dilute sulfuric acid tank (5) is connected with the upper side of the washing and purification tower (11) through a pipeline to form a circulation; The outlet of the sulfuric acid storage tank (14) is connected to the upper side of the washing and purification tower (11) through the sulfuric acid circulating pump (15); The tail gas treatment unit comprises a caustic washing tower (16), a lye tank (17), a lye pump (18) and a distributor (19); The input end of the caustic washing tower (16) is connected with the output end of the top of the absorption tower (13), the bottom output end of the caustic washing tower (16) is connected with the lye tank (17), and the output end of the lye tank (17) is connected to the distributor (19) inside the caustic washing tower (16) through the lye pump (18).

2. A system for producing concentrated sulphuric acid from dilute sulphuric acid of an alkylation unit as claimed in claim 1, wherein, The distributor (19) is located at the upper end inside the caustic washing tower (16).

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