A sulfur recovery process, sulfur production device, and desulfurization device

Abstract

This invention provides a sulfur recovery process, a sulfur production device, and a desulfurization device. The sulfur recovery process includes: sulfur production from acidic gas via high-temperature thermal reaction and single-stage Claus sulfur production to obtain sulfur production tail gas; the sulfur production tail gas undergoes a first reaction with a second oxygen-containing gas in an incinerator, oxidizing all sulfur-containing components in the tail gas to sulfur dioxide, obtaining primary process gas; the primary process gas enters a reactor and undergoes a second reaction with a desulfurizing agent, adsorbing the sulfur dioxide in the primary process gas and converting it into sulfate, obtaining secondary process gas and a desulfurizing agent to be regenerated; at least a portion of the desulfurizing agent to be regenerated enters a regenerator to obtain regenerated desulfurizing agent; the regenerated desulfurizing agent is returned to the reactor to participate in the second reaction; the secondary process gas is treated by heat exchange and washing to obtain purified tail gas. This invention has advantages such as a short process flow, low energy consumption, simple operation, low investment, small footprint, high sulfur recovery rate, and near-zero sulfur dioxide emissions from the purified tail gas.

Description

Technical Field

[0001] This invention relates to the field of sulfur recovery, specifically to a sulfur recovery process, a sulfur production device, and a desulfurization device. Background Technology

[0002] Sulfur recovery units mainly consist of a sulfur production unit and a sulfur production tail gas treatment unit. The sulfur production unit comprises two parts: a high-temperature thermal reaction and a low-temperature Claus reaction for sulfur production. Traditionally, the low-temperature Claus reaction for sulfur production uses a two-stage Claus process. With increasingly stringent environmental standards, there is a growing trend towards using three-stage Claus, super Claus, and ultra-optimal Claus processes to improve sulfur recovery rates and reduce tail gas treatment loads. The sulfur production tail gas treatment unit is based on the SCOT process and its upgraded reduction absorption process, with SSR and ZHSR processes being typical examples. This type of process first reduces the tail gas with hydrogen, thus... , COS Sulfur-containing components are converted into Then, through heat exchange, rapid cooling, amine absorption, and desorption, the amine solution is removed. After parsing Returning to the sulfur production unit, the purified tail gas is incinerated and discharged after waste heat recovery. To meet the GB31570-2015 standard, further deep purification measures such as alkaline washing (e.g., sodium desulfurization) are required. Patent CN113385004A discloses the FECOT process, which optimizes and improves the sulfur production tail gas treatment process, possessing technical advantages such as low investment, low energy consumption, and no acidic water or alkaline residue emissions. However, currently, sulfur recovery devices generally suffer from technical defects in their sulfur production and tail gas treatment units, including long process flows, high energy consumption, large investment scale, large equipment footprint, low sulfur recovery rate, and high sulfur dioxide content in the purified tail gas. These are technical problems that urgently need to be solved in this field. Summary of the Invention

[0003] This invention provides a sulfur recovery process, a sulfur production device, and a desulfurization device to at least solve the problems of existing technologies, such as long process flow, large equipment footprint, high energy consumption, low sulfur recovery rate, and poor purification of exhaust gas. Issues such as high content.

[0004] One aspect of the present invention provides a sulfur recovery process, comprising the following steps: S1, acidic gas and a first oxygen-containing gas undergo a high-temperature thermal reaction in a sulfur-producing furnace to obtain primary sulfur-producing process gas; the primary sulfur-producing process gas is cooled and subjected to a single-stage Claus reaction to obtain sulfur-producing tail gas and liquid sulfur; S2, the sulfur-producing tail gas and a second oxygen-containing gas undergo a first reaction in an incinerator to obtain primary process gas; the first reaction satisfies the following condition: the sulfur-containing components in the sulfur-producing tail gas are completely oxidized to sulfur dioxide by the second oxygen-containing gas; S3, the primary process gas from the incinerator enters a reactor and undergoes a second reaction with a desulfurizing agent in the reactor to obtain secondary process gas and a desulfurizing agent to be generated; the second reaction satisfies the following condition: the sulfur dioxide in the primary process gas is adsorbed by the desulfurizing agent and converted into sulfate; S4, the desulfurizing agent to be generated is output from the reactor and at least partially enters a regenerator for regeneration to obtain regenerated desulfurizing agent; the regenerated desulfurizing agent is returned to the reactor to participate in the second reaction; the secondary process gas from the reactor is subjected to heat exchange and washing treatment to obtain purified tail gas.

[0005] According to one embodiment of the present invention, the process of obtaining sulfur-producing tail gas and liquid sulfur after cooling and single-stage Claus reaction of the primary sulfur-producing process gas includes: the primary sulfur-producing process gas is heated by a waste heat boiler, and then successively cooled and subjected to single-stage Claus reaction to separate the sulfur-producing tail gas and liquid sulfur; and / or, the cooling and single-stage Claus reaction includes: the primary sulfur-producing process gas is output from the waste heat boiler and enters a primary condenser for cooling and separation to obtain secondary sulfur-producing process gas and liquid sulfur; the secondary sulfur-producing process gas enters a primary heater and is heated to 210-260°C, and then enters a primary converter to undergo a single-stage Claus reaction to obtain tertiary sulfur-producing process gas; the tertiary sulfur-producing process gas enters a secondary condenser for cooling and separation to obtain sulfur-producing tail gas and liquid sulfur.

[0006] According to one embodiment of the present invention, the first oxygen-containing gas includes air; and / or, the second oxygen-containing gas includes air; and / or, the temperature of the first reaction is 600~750°C; and / or, the temperature of the second reaction is 650~700°C.

[0007] According to one embodiment of the present invention, the secondary process gas from the reactor sequentially passes through a superheater, a waste heat boiler, a steam generator, and a preheater before undergoing the washing treatment; and / or, the second oxygen-containing gas exchanges heat with the secondary process gas flowing through the preheater to obtain preheated oxygen-containing gas; the preheated oxygen-containing gas and the sulfur-producing tail gas enter the incinerator to undergo the first reaction; and / or, deoxygenated water enters the waste heat boiler and exchanges heat with the secondary process gas flowing through the waste heat boiler to generate medium-pressure steam; the medium-pressure steam enters the superheater and exchanges heat with the secondary process gas flowing through the superheater.

[0008] According to one embodiment of the present invention, the washing process includes: the secondary process gas, after being output from the preheater, enters a quench scrubbing tower and comes into contact with the scrubbing liquid for quench scrubbing to obtain purified tail gas and non-gas phase material; the non-gas phase material enters a first filter for first solid-liquid separation to obtain a first filtrate and a recovered desulfurizing agent; the recovered desulfurizing agent is slurried in a slurry tank and enters the reactor; a portion of the first filtrate enters a second filter for second solid-liquid separation to obtain a second filtrate and a second filter residue; the second filtrate is cooled by an air cooler and returned to the quench scrubbing tower, and the second filter residue is reused in a catalytic cracking unit.

[0009] According to one embodiment of the present invention, the regeneration process includes: the desulfurizing agent to be recycled entering the regenerator undergoes a regeneration reaction with a reducing agent to obtain the regenerated desulfurizing agent; wherein the regeneration reaction satisfies the following condition: the sulfur element in the sulfate is reduced by the reducing agent to hydrogen sulfide and / or sulfur dioxide.

[0010] According to one embodiment of the present invention, the reducing agent includes hydrogen and / or elemental sulfur; and / or, the temperature of the regeneration reaction is 500–630°C.

[0011] According to one embodiment of the present invention, the dry basis SO2 content in the purified exhaust gas is ≤1 mg / Nm³. 3 ; and / or, the dry basis particulate matter content in the purified exhaust gas is ≤30 mg / Nm³. 3 .

[0012] In another aspect, the present invention provides a sulfur production apparatus for performing step S1 of the above-described sulfur recovery process, comprising: a sulfur production furnace, a waste heat boiler, a primary condenser, a primary heater, a primary converter, and a secondary condenser connected in sequence.

[0013] In another aspect, the present invention provides a desulfurization device for performing steps S2 to S4 of the above-described sulfur recovery process, comprising: an incinerator having a first feed inlet, a second oxygen-containing gas inlet, and a primary process gas outlet;

[0014] The reactor is equipped with a pre-regenerating agent circulation inlet, a secondary process gas outlet, a pre-regenerating agent outlet, a primary process gas inlet connected to the primary process gas outlet of the incinerator, a fresh desulfurizing agent inlet, a regenerated desulfurizing agent inlet, and a desulfurizing agent slurry inlet.

[0015] The regenerator is provided with a regenerated gas outlet connected to the regenerated gas inlet of the regenerated waste pot, a regenerated agent inlet connected to the regenerated agent outlet of the reactor, a regenerated agent outlet connected to the regenerated agent circulation inlet of the reactor, a reducing agent inlet, and a stripping gas inlet.

[0016] The regeneration waste pot is provided with a regeneration gas passage; the regeneration gas passage of the regeneration waste pot is connected to the regenerant outlet of the regenerator;

[0017] The third filter is equipped with a regeneration gas passage and a backflush gas passage; the backflush gas passage of the third filter is connected to the first feed inlet of the incinerator.

[0018] The regeneration gas channel of the regeneration waste pot and the regeneration gas channel of the third filter are connected to the inlet of the sulfur production furnace of the sulfur production unit.

[0019] The sulfur production unit has a secondary condenser with a three-stage sulfur production process gas inlet, a sulfur production tail gas outlet, and a liquid sulfur outlet. The sulfur production tail gas outlet of the secondary condenser is connected to the first feed inlet of the incinerator.

[0020] The superheater is equipped with a two-stage process gas passage;

[0021] The waste heat boiler is equipped with a two-stage process gas passage.

[0022] The steam generator is equipped with a two-stage process gas passage;

[0023] The preheater is equipped with a two-stage process gas passage;

[0024] The quench scrubbing tower is provided with a secondary process gas channel, a non-gas phase material channel, and a scrubbing liquid channel; the secondary process gas channel of the superheater, the secondary process gas channel of the waste heat boiler, the secondary process gas channel of the steam generator, the secondary process gas channel of the preheater, and the secondary process gas channel of the quench scrubbing tower are connected in sequence;

[0025] The slurry tank is provided with a first material inlet, a second material inlet, and a material outlet. The material outlet of the slurry tank is connected to the gas phase section of the reactor. The first material inlet of the slurry tank is connected to the first filter residue outlet of the first filter, and the second material inlet of the slurry tank is connected to the second filtrate outlet of the first filter.

[0026] The first filter has a non-gas phase material inlet, a first filter residue outlet, a first filtrate outlet, and a second filtrate outlet; the non-gas phase material inlet of the first filter is connected to the non-gas phase material channel of the quench washing tower, the first filter residue outlet of the first filter is connected to the first material inlet of the slurry tank, and the second filtrate outlet of the first filter is connected to the second material inlet of the slurry tank.

[0027] An air cooler is provided with a washing liquid channel; the washing liquid channel of the air cooler is connected to the washing liquid channel of the washing tower;

[0028] The second filter is provided with a first filtrate inlet, a second filter residue outlet, and a third filtrate outlet; the first filtrate inlet of the second filter is connected to the first filtrate outlet of the first filter, and the third filtrate outlet of the second filter is connected to the washing liquid channel of the air cooler.

[0029] The new agent tank is equipped with a fresh desulfurizing agent channel; the fresh desulfurizing agent channel of the new agent tank is connected to the fresh desulfurizing agent inlet of the reactor.

[0030] This invention provides a novel sulfur recovery process (Z-QSR process, ZQ sulfur recovery for short), in which acidic gas is processed through a single-stage Claus process to produce sulfur containing sulfides. , COS , The process involves treating sulfur-generating tail gas (such as sulfur dioxide, sulfur-containing gas, etc.). The tail gas undergoes a first reaction with a second oxygen-containing gas, oxidizing all sulfur-containing components into sulfur dioxide. The sulfur dioxide-laden tail gas then comes into contact with a desulfurizing agent for an adsorption desulfurization reaction (the second reaction), converting sulfur oxides into sulfates. Subsequent washing and filtration processes ensure the purified tail gas meets emission standards. The desulfurizing agent is at least partially regenerated before being returned to participate in the adsorption desulfurization reaction. Compared to conventional sulfur-generating tail gas (or sulfur tail gas) treatment processes such as SCOT, this invention offers advantages such as a shorter process flow, lower energy consumption, simpler operation, lower investment, smaller footprint, higher sulfur recovery rate, and near-zero sulfur dioxide emissions from the purified tail gas. This makes it significant for practical industrial applications. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of an improved sulfur production unit according to an embodiment of the present invention.

[0032] Figure 2 This is a schematic diagram of the desulfurization unit according to one embodiment of the present invention. Detailed Implementation

[0033] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below in conjunction with specific embodiments. Obviously, the described embodiments are only some embodiments of this invention, not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0034] This invention provides a desulfurization method for sulfur production tail gas, comprising the following steps: S1, acidic gas and a first oxygen-containing gas undergo a high-temperature thermal reaction in a sulfur production furnace to obtain primary sulfur production process gas; the primary sulfur production process gas is cooled and subjected to a single-stage Claus reaction to obtain sulfur production tail gas and liquid sulfur; S2, the sulfur production tail gas and a second oxygen-containing gas undergo a first reaction in an incinerator to obtain primary process gas; the first reaction satisfies the following condition: the sulfur-containing components in the sulfur production tail gas are completely oxidized to sulfur dioxide by the second oxygen-containing gas; S3, the primary process gas from the incinerator... Gas enters the reactor and undergoes a second reaction with the desulfurizing agent (including regenerated and fresh desulfurizing agents) to obtain secondary process gas and desulfurizing agent to be generated. The second reaction satisfies the following conditions: sulfur dioxide in the primary process gas is adsorbed by the desulfurizing agent and converted into sulfate; S4, after the desulfurizing agent is output from the reactor, at least a portion enters the regenerator for regeneration to obtain regenerated desulfurizing agent; the regenerated desulfurizing agent returns to the reactor to participate in the second reaction; the secondary process gas from the reactor is treated by heat exchange and washing to obtain purified tail gas. In this invention, the sulfur-containing component in the acidic gas is hydrogen sulfide, which, after a high-temperature thermal reaction, yields primary sulfur production process gas, the sulfur-containing component of which is... , COS , The main reaction equations are shown below:

[0035] 2H₂S + 3O₂ = 2SO₂ + 2H₂O

[0036] 2H₂S + SO₂ = 3 / xS x +2H2O

[0037] CH4 + 2H2S = 4H2 + CS2

[0038] CH4 + 2O2 = 2H2O + CO2

[0039] CS2 + CO2 = 2COS.

[0040] In some embodiments, the temperature of the high-temperature thermal reaction is 900–1450°C, and the temperature at which the secondary sulfur production process gas undergoes a single-stage Claus reaction in the primary converter is 300–400°C.

[0041] After cooling and a single-stage Claus reaction, the gas from the primary sulfur production process yields sulfur tail gas and liquid sulfur. The main reaction formulas are shown below:

[0042] 2H₂S + 3O₂ = 2SO₂ + 2H₂O

[0043] 2H₂S + SO₂ = 3 / xS x +2H2O

[0044] COS + H₂O = H₂S + CO₂

[0045] CS2 + 2H2O = 2H2S + CO2.

[0046] In some embodiments, the cooling and single-stage Claus reaction includes: the primary sulfur production process gas is output from the waste heat boiler and then enters the primary condenser for cooling and separation to obtain secondary sulfur production process gas and liquid sulfur; the secondary sulfur production process gas enters the primary heater and is heated to 210°C-260°C, then enters the primary converter to undergo a single-stage Claus reaction to obtain tertiary sulfur production process gas; the tertiary sulfur production process gas enters the secondary condenser for cooling and separation to obtain sulfur production tail gas and liquid sulfur.

[0047] This invention improves the sulfur production unit by converting the original two- or three-stage Claus sulfur production process (including super Claus and ultra-optimal Claus processes) into a single-stage Claus sulfur production process; after the improvement, the sulfur production tail gas... , COS , The total sulfide content is increased from 1.121%(v) in the tail gas of the original two-stage Claus process to 2.472%(v) in the tail gas of the single-stage process (%(v) is a unit of volume concentration, representing the percentage of a component's volume in the total volume of the sulfur-producing tail gas). All sulfides are treated by the subsequent tail gas treatment unit. Compared with the two-stage Claus process, the core improvement of the sulfur-producing unit in this invention is the reduction of the secondary process gas heater, secondary converter, and tertiary condenser. The schematic flow is as follows: Figure 1 As shown, Figure 1 The content within the dashed box is the deleted content.

[0048] In this invention, the sulfur-containing components of the sulfur-producing tail gas mainly include H2S, CS2, COS, and S. x After the first reaction in the tail gas unit, sulfur-containing components such as SO2 are completely oxidized to SO2 by oxygen in the second oxygen-containing gas. The main reaction formula is shown below:

[0049] 2H₂S + 3O₂ = 2SO₂ + 2H₂O

[0050] 2COS + 3O2 = 2CO2 + 2SO2

[0051] CS2 + 3O2 = 2SO2 + CO2

[0052] S x +xO2=xSO2

[0053] H₂ + 1 / 2O₂ = H₂O

[0054] CO + 1 / 2O2 = CO2.

[0055] In some embodiments, the first oxygen-containing gas includes air, and the second oxygen-containing gas includes air.

[0056] In some embodiments, the temperature of the first reaction is 600~750°C.

[0057] The primary process gas from the incinerator enters the reactor and comes into contact with the desulfurizing agent to undergo a second reaction. This reaction causes sulfur oxides to be adsorbed and converted into sulfates by the desulfurizing agent. SO2 present in the primary process gas further reacts with a second oxygen-containing gas to generate SO3, which then reacts with the desulfurizing agent to form sulfates. Specifically, the desulfurizing agent may include alkaline oxides and generally may also include trace amounts of non-alkaline oxides to improve the reduction performance of the desulfurizing agent and make it easier to regenerate. Alkaline oxides include, for example, oxides of alkaline earth metals, preferably active magnesium oxide. This desulfurizing agent is particularly effective at high temperatures (as described in the second reaction temperature below) to oxidize SO2 in the primary process gas to SO3, and to rapidly adsorb SO3 and generate stable sulfates. It can also react with a reducing agent to achieve rapid decomposition and reduction (especially at high temperatures (as described in the regeneration reaction temperature below)) to achieve regeneration.

[0058] Specifically, the main reaction formula for the second reaction described above is shown below:

[0059] 2SO2 + O2 = 2SO3

[0060] XO + SO3 = XSO4 (XO represents basic oxide, and X represents metal).

[0061] In some embodiments, a reaction settling device is also provided above the reactor to allow the gas-solid mixture to settle naturally and be separated by cyclone separation, thus separating the gas from the desulfurizing agent particles and providing reaction space for the second reaction. The primary process gas directly enters the lower part of the reactor (also known as the riser reactor), where the temperature is 650°C to 700°C (i.e., the temperature of the second reaction). It mixes sequentially with the circulating desulfurizing agent from the reaction settling device and the regenerator from the regenerator, and is then fluidized and lifted together to the reaction settling device. The gas is separated from the desulfurizing agent particles through natural settling and cyclone separation, and the second reaction occurs during the lifting and separation process.

[0062] In some implementations, the secondary process gas from the reactor passes sequentially through a superheater, a waste heat boiler, a steam generator, and a preheater before undergoing scrubbing treatment.

[0063] In some embodiments, the second oxygen-containing gas exchanges heat with the secondary process gas flowing through the preheater to obtain preheated oxygen-containing gas; the preheated oxygen-containing gas undergoes a first reaction with the sulfur-producing tail gas in the incinerator. Deoxygenated water enters the waste heat boiler and exchanges heat with the secondary process gas flowing through it to generate medium-pressure steam; the medium-pressure steam enters the superheater and exchanges heat with the secondary process gas flowing through it. The heat from the secondary process gas superheats the medium-pressure steam, and the superheated medium-pressure steam is discharged from the steam superheater. This process recovers heat, facilitating further energy savings.

[0064] In some embodiments, the dry basis SO2 content in the secondary process gas (also known as purified process gas) from the reactor and after adsorption and desulfurization by a desulfurizing agent is ≤1 mg / Nm³. 3 The wet-based particulate matter content in the secondary process gas was 200 mg / Nm³. 3 The temperature of the secondary process gas is 650–700℃.

[0065] In some implementations, the secondary process gas from the reactor undergoes a series of heat exchanges, passing through a superheater (also known as a steam superheater), a waste heat boiler (also known as a steam waste heat boiler), a steam generator (also known as a low-pressure steam generator), and a preheater (also known as a second oxygen-containing gas preheater), before entering a quench scrubbing tower for washing. Specifically, in the superheater, the secondary process gas is cooled, converting the saturated steam in the superheater into superheated steam. In the waste heat boiler, the high-temperature heat of the secondary process gas is used to generate medium-pressure steam, achieving energy recovery and providing a steam heat source for the process system. In the steam generator, the secondary process gas continues to release heat, which is used to heat the deoxygenated water to produce low-pressure saturated steam. In the preheater, the secondary process gas exchanges heat with the second oxygen-containing gas, thereby preheating the second oxygen-containing gas to obtain preheated oxygen-containing gas, while simultaneously further cooling the secondary process gas.

[0066] In some embodiments, the temperature of the secondary process gas after heat exchange in the superheater is 500-550°C, the temperature of the secondary process gas after heat exchange in the waste heat boiler is 280-300°C, the temperature of the secondary process gas after heat exchange in the steam generator is 160-180°C, and the temperature of the secondary process gas after heat exchange in the preheater is 130-150°C. The steam pressure in the superheater is 3.5 MPa-4.4 MPa, the steam pressure in the waste heat boiler is 3.5 MPa-4.4 MPa, and the steam pressure in the steam generator is 0.3 MPa-0.4 MPa.

[0067] In some embodiments, the above-mentioned washing process includes: after the secondary process gas is output from the preheater, it enters the quench scrubbing tower and comes into contact with the scrubbing liquid for quench scrubbing, to obtain purified tail gas and non-gas phase materials respectively; the non-gas phase materials enter the first filter for solid-liquid separation to obtain the first filtrate and the recovered desulfurizing agent; the recovered desulfurizing agent is slurried in the slurry tank and enters the reactor; part of the first filtrate enters the second filter for second solid-liquid separation to obtain the third filtrate and the second filter residue; the third filtrate is cooled by the air cooler and returned to the quench scrubbing tower, and the second filter residue is used again in the catalytic cracking unit with the clean water.

[0068] Specifically, the washing liquid may include water. The washing liquid (also known as circulating washing liquid) is cooled by an air cooler and then sprayed at the top of the washing tower. By quenching and washing the secondary process gas, the secondary process gas can be cooled and purified, removing particulate matter and other impurities carried in it. The top temperature of the quenching and washing tower is 55~75℃.

[0069] In some embodiments, the regeneration process includes: the desulfurizing agent to be recycled entering the regenerator reacts with a reducing agent to obtain a regenerated desulfurizing agent; wherein the regeneration reaction satisfies the condition that the sulfur element in the sulfate is reduced to hydrogen sulfide by the reducing agent. Optionally, the reducing agent may include hydrogen gas and / or elemental sulfur, and the temperature of the regeneration reaction is 500–630°C, which is beneficial to improving the regeneration efficiency, and the desulfurizing agent's resolution rate is generally as high as 95% or more. In some embodiments, the reducing agent is hydrogen gas, and the main reaction formula of the regeneration reaction is shown below: XSO4 + H2 → XO + H2S + H2O (XSO4 represents sulfate). In specific implementation, the desulfurizing agent to be recycled enters the regenerator from the inlet of the regenerator, and the regenerated desulfurizing agent enters the reactor from the outlet of the regenerator. The temperature of the regeneration reaction can be controlled such that the temperature of the inlet of the regenerator and the temperature of the outlet of the regenerator are both 500–630°C.

[0070] Further, after the regeneration reaction, a regenerated desulfurizing agent and regenerated gas containing hydrogen sulfide are obtained. The regenerated gas from the regenerator is heat-exchanged in the regeneration waste pot and then enters the third filter for filtration to remove solid particles, resulting in filtered regenerated gas. Additionally, as... Figure 2 As shown, the regenerator may also be provided with a stripping gas inlet for introducing stripping gas into the regenerator to strip the hydrogen sulfide adsorbed on the solid particles. Specifically, the stripping gas may be water vapor.

[0071] Furthermore, backflush gas enters the third filter through its backflush gas inlet to blow off particulate matter adsorbed on the filter screen, restoring its filtration function. The backflush gas can specifically be nitrogen. The filtered regenerated gas can then participate in sulfur production in the sulfur production unit, achieving sulfur recovery. In practice, the particulate matter content in the filtered regenerated gas can be controlled by adjusting the filtration precision of the third filter to meet the standard requirements for sulfur products. Generally, the particulate matter content in the regenerated gas from the regenerator is ≤200 mg / Nm³. 3 After heat exchange in the regeneration boiler and filtration by the third filter, the particle size of the particulate matter in the regeneration gas is ≤1.3μm.

[0072] In practice, fresh desulfurizing agent can be added to the reactor as needed through a new tank containing the desulfurizing agent, such as... Figure 2 As shown.

[0073] In some embodiments, the dry basis SO2 content in the purified exhaust gas is ≤1 mg / Nm³. 3 The dry basis particulate matter content in the purified exhaust gas is ≤30mg / Nm³. 3 .

[0074] In some embodiments, taking a 100,000-ton / year sulfur recovery unit as an example, based on a hydrogen sulfide content of 10 mg / kg in liquid sulfur, a desulfurizing agent consumption of 40 tons / year, a sulfur capacity of 2.32% (as SO2), and a total sulfur loss of 1.464 tons / year, the sulfur recovery rate of the above sulfur recovery process is 99.99854%.

[0075] like Figure 1 As shown, the sulfur production apparatus of the present invention includes: a sulfur production furnace, a waste heat boiler, a primary condenser, a primary heater, a primary converter, and a secondary condenser connected in sequence.

[0076] like Figure 2 As shown, the desulfurization device of the present invention includes: an incinerator, which is provided with a first feed inlet, a second oxygen-containing gas inlet and a primary process gas outlet;

[0077] The reactor is equipped with a pre-regenerating agent circulation inlet, a secondary process gas outlet, a pre-regenerating agent outlet, a primary process gas inlet connected to the primary process gas outlet of the incinerator, a fresh desulfurizing agent inlet, a regenerated desulfurizing agent inlet, and a desulfurizing agent slurry inlet.

[0078] The regenerator is equipped with a regenerated gas outlet connected to the regenerated gas inlet of the regenerated waste pot, a regenerated agent inlet connected to the regenerated agent outlet of the reactor, a regenerated agent outlet connected to the regenerated agent inlet of the reactor, a reducing agent inlet, and a stripping gas inlet.

[0079] The regeneration waste heat boiler is equipped with a regeneration gas passage;

[0080] The third filter is equipped with a regeneration gas passage and a backflush gas passage;

[0081] The regeneration gas passage of the regeneration waste pot and the regeneration gas passage of the third filter are connected to the inlet of the sulfur production furnace of the sulfur production unit.

[0082] The secondary condenser (also known as the sulfur production unit secondary condenser) is equipped with a three-stage sulfur production process gas inlet, a sulfur production tail gas outlet, and a liquid sulfur outlet; the sulfur production tail gas outlet of the secondary condenser is connected to the first feed inlet of the incinerator.

[0083] The backflush gas passage of the third filter is connected to the first feed inlet of the incinerator;

[0084] The superheater is equipped with a two-stage process gas passage;

[0085] The waste heat boiler is equipped with a two-stage process gas passage.

[0086] The steam generator is equipped with a two-stage process gas passage;

[0087] The preheater is equipped with a two-stage process gas passage;

[0088] The quench scrubbing tower is equipped with a secondary process gas channel, a non-gas phase material channel, and a scrubbing liquid channel; the secondary process gas channels of the superheater, the waste heat boiler, the steam generator, the preheater, and the quench scrubbing tower are connected in sequence.

[0089] The slurry tank is provided with a first material inlet, a second material inlet, and a material outlet. The material outlet of the slurry tank is connected to the gas phase section of the reactor. The first material inlet of the slurry tank is connected to the first filter residue outlet of the first filter, and the second material inlet of the slurry tank is connected to the second filtrate outlet of the first filter.

[0090] The first filter has a non-gas phase material inlet, a first filter residue outlet, a first filtrate outlet, and a second filtrate outlet; the non-gas phase material inlet of the first filter is connected to the non-gas phase material channel of the quench scrubbing tower, the first filter residue outlet of the first filter is connected to the first material inlet of the slurry tank, and the second filtrate outlet of the first filter is connected to the second material inlet of the slurry tank.

[0091] The air cooler is equipped with a washing liquid channel; the washing liquid channel of the air cooler is connected to the washing liquid channel of the washing tower.

[0092] The second filter has a first filtrate inlet, a second filter residue outlet, and a third filtrate outlet; the first filtrate inlet of the second filter is connected to the first filtrate outlet of the first filter, and the third filtrate outlet of the second filter is connected to the washing liquid channel of the air cooler.

[0093] The new agent tank is equipped with a fresh desulfurizing agent channel; the fresh desulfurizing agent channel of the new agent tank is connected to the fresh desulfurizing agent inlet of the reactor.

[0094] In some embodiments, the regenerator includes a regeneration section for carrying out the regeneration reaction and a conveying section for conveying the regenerated desulfurizing agent to the reactor, with the regenerating agent outlet of the regenerator located in the conveying section.

[0095] Example 1

[0096] Adopting such Figure 1 The sulfur production unit shown produces sulfur from acidic gas. The sulfur production process is as follows:

[0097] Acid gas and the first oxygen-containing gas enter the sulfur-making furnace and undergo a high-temperature thermal reaction to generate primary sulfur-making process gas. After being cooled by heat exchange in a waste heat boiler, the primary sulfur-making process gas enters the primary condenser for cooling and gas-liquid separation to obtain secondary sulfur-making process gas and liquid sulfur. Subsequently, the secondary sulfur-making process gas enters the primary heater and is heated to 210-610°C before entering the primary converter for a single-stage Claus reaction to obtain tertiary sulfur-making process gas. The tertiary sulfur-making process gas enters the secondary condenser from the tertiary sulfur-making process gas inlet for cooling and gas-liquid separation to obtain sulfur-making tail gas and liquid sulfur.

[0098] The first oxygen-containing gas includes air, and the temperature of the high-temperature thermal reaction is 900–1450°C. The temperature of the second-stage sulfur production process gas undergoing a single-stage Claus reaction in the first-stage converter is 300–400°C.

[0099] Adopting such Figure 2 The desulfurization unit shown desulfurizes the sulfur production tail gas generated by the sulfur production unit mentioned above. The desulfurization process is as follows:

[0100] The second oxygen-containing gas enters the preheater through its second oxygen-containing gas channel and exchanges heat with the secondary process gas flowing through the preheater's secondary process gas channel. This cools the secondary process gas, while simultaneously preheating the second oxygen-containing gas through the heat from the secondary process gas, resulting in preheated oxygen-containing gas. The preheated oxygen-containing gas then undergoes a first reaction with the sulfur-producing tail gas in the incinerator at a temperature of 600-750°C. The sulfur-containing components in the sulfur-producing tail gas are oxidized to sulfur dioxide, yielding the primary process gas.

[0101] The primary process gas is output from the primary process gas outlet of the incinerator and enters the reactor from the primary process gas inlet of the reactor. In the reactor, it undergoes a second reaction with the desulfurizing agent entering the reactor. The temperature of the second reaction is 650~700℃, and the secondary process gas and the desulfurizing agent to be generated are obtained respectively.

[0102] Secondary process gas exits from the reactor's secondary process gas outlet and flows sequentially through the secondary process gas channels of the superheater, the waste heat boiler, the evaporator, and the preheater. Specifically, deoxygenated water enters the steam / water channel of the waste heat boiler, exchanging heat with the secondary process gas flowing through its channel. During this heat exchange, water vaporizes to generate medium-pressure steam (3.5–4.4 MPa), simultaneously cooling the secondary process gas. This medium-pressure steam then enters the superheater's secondary process gas channel, exchanging heat with the secondary process gas flowing through it. During this heat exchange, medium-pressure steam (also known as superheated medium-pressure steam, 3.5–4.4 MPa) is generated, further cooling the secondary process gas. In the steam generator, the secondary process gas continues to release heat, producing low-pressure steam (0.3–0.4 MPa).

[0103] In the preheater, the secondary process gas from the steam generator exchanges heat with the second oxygen-containing gas to preheat the second oxygen-containing gas, thereby obtaining preheated oxygen-containing gas, while the secondary process gas is further cooled.

[0104] The secondary process gas, cooled from the preheater, enters the scrubbing tower and comes into contact with the scrubbing liquid (an aqueous solution containing a small amount of sulfate and a trace amount of sulfite) for rapid cooling and scrubbing to remove entrained solid particles, resulting in purified tail gas (which can be discharged into the atmosphere) and non-gaseous materials.

[0105] Non-gas phase materials are discharged from the bottom of the scrubbing tower and enter the first filter for solid-liquid separation to obtain the first filtrate and recovered desulfurizing agent; the recovered desulfurizing agent is slurried in the slurry tank and enters the reactor; the first filtrate enters the second filter for solid-liquid separation to obtain the third filtrate and the second filter residue; the third filtrate is cooled by the air cooler and returned to the quench scrubbing tower as scrubbing liquid for recycling, and the second filter residue is sent to the catalytic cracking unit for secondary use;

[0106] After the desulfurizing agent is discharged from the reactor's outlet, a portion returns to the reactor through the second inlet to continue participating in the second reaction. The remaining portion enters the regenerator through the first inlet, where it undergoes a third reaction with the reducing agent. Sulfate is reduced to hydrogen sulfide, and the desulfurizing agent regains its activity to become regenerated desulfurizing agent, while generating regenerated gas containing hydrogen sulfide. Any insufficient desulfurizing agent is replenished from the new agent tank.

[0107] The regenerated desulfurizing agent is output from the regenerator outlet and returned to the reactor from the reactor inlet to participate in the second reaction; water vapor enters the regenerator through the stripping gas inlet to strip the hydrogen sulfide adsorbed on the solid particles such as the desulfurizing agent; the regenerated gas is output from the regenerated gas outlet and flows through the regenerated waste pot to cool the regenerated gas. After being cooled by heat exchange in the regenerated waste pot, the regenerated gas is filtered by the third filter and then sent to the sulfur production unit to produce sulfur.

[0108] The main parameters such as reagent usage and energy consumption are shown in Table 1. After desulfurization, the emissions of sulfur dioxide, particulate matter, consumption of each reagent, and the costs and benefits calculated based on reference prices are shown in Table 2.

[0109] Comparative Example 1

[0110] The existing two-stage Claus + SCOT + sodium desulfurization (also known as alkaline washing) process was used to desulfurize the sulfur production tail gas with basically the same properties as in Example 1. The main energy consumption and other parameters are shown in Table 1. After desulfurization, the emissions of sulfur dioxide, particulate matter, consumption of various reagents, and engineering costs and benefits calculated at reference prices are shown in Table 2.

[0111] Table 1

[0112]

[0113] The consumption indicators in Table 1 are calibration data for a device using a classic process.

[0114] Table 2

[0115]

[0116] Reference prices (unit price): Sulfur 1000 yuan / ton, Sodium hydroxide (solid alkali) 2300 yuan / ton, Hydrogen 12,500 yuan / ton, Fuel gas and standard oil used for heating 1500 yuan / ton, MDEA (methyl diethanolamine) used in amine absorption process 30,000 yuan / ton, Desulfurizing agent 100,000 yuan / ton.

[0117] "kgoe / t sulfur" indicates the energy consumption for desulfurization treatment of the tail gas generated from the production of 1 ton (t) of sulfur. Particulate matter emissions in Table 2 refer to dry-basis particulate matter emissions in the purified tail gas.

[0118] In Example 1, sulfur production tail gas is obtained through a single-stage Claus sulfur production process. Then, through a high-temperature oxidation process, the sulfides in the sulfur production tail gas (or sulfur tail gas) are oxidized into sulfur oxides. Combined with the high-temperature adsorption process of the desulfurizing agent and the regeneration process of the desulfurizing agent, along with subsequent washing and filtration treatments, efficient sulfur recovery is achieved. Compared with existing sulfur tail gas treatment schemes, this method has at least the following advantages:

[0119] (1) Low investment and good returns

[0120] Taking a sulfur recovery unit with a capacity of 100,000 tons / year as an example, and referring to the prices of conventional reagents, the engineering cost of Example 1 is significantly lower than that of Comparative Example 1, saving 22.05 million yuan in engineering investment. Calculated based on conventional output-consumption costs, the annual increase in benefits is 28.67 million yuan. The benefits of Example 1 are better than those of Comparative Example 1, which further illustrates the significant practical value of the desulfurization process of this invention.

[0121] (2) The emission of sulfur dioxide in the exhaust gas has been improved from meeting the emission standards to near zero.

[0122] Compared to Comparative Example 1, the sulfur dioxide emissions in the purified exhaust gas were ≤50 mg / Nm³. 3 Example 1: The sulfur dioxide emission in the purified exhaust gas is ≤1 mg / Nm³. 3 .

[0123] (3) Low energy consumption

[0124] According to statistics, the average energy consumption of existing sulfur recovery devices (such as SCOT process, SSR process, ZHSR process, etc.) is around -106.1 kgoe / t sulfur, while the energy consumption of Example 1 is -270.8 kgoe / t sulfur, which is far lower than the existing average energy consumption level (a decrease of 155% compared to the existing average energy consumption level). At the same time, as can be seen from Tables 1 and 2, compared with Comparative Example 1, the energy consumption of Example 1 is also significantly reduced, from -152.1 kgoe / t sulfur to -270.8 kgoe / t sulfur, a decrease of 78%. This further illustrates that the solution of the present invention can significantly reduce energy consumption while efficiently recovering sulfur.

[0125] (4) The sulfur recovery rate is significantly improved compared with other processes.

[0126] The most advanced sulfur recovery technology in the world currently has a sulfur recovery rate of 99.9900%, while the sulfur recovery rate of this invention is 99.99854%.

[0127] The embodiments of the present invention have been described above. However, the present invention is not limited to the above embodiments. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A sulfur recovery process, characterized in that, Includes the following steps: S1. Acid gas and the first oxygen-containing gas undergo a high-temperature thermal reaction in the sulfur-making furnace to obtain primary sulfur-making process gas. After cooling and a single-stage Claus reaction, the primary sulfur-making process gas yields sulfur-making tail gas and liquid sulfur. S2. The sulfur-producing tail gas and the second oxygen-containing gas undergo a first reaction in the incinerator to obtain primary process gas; the first reaction satisfies the following condition: the sulfur-containing components in the sulfur-producing tail gas are completely oxidized to sulfur dioxide by the second oxygen-containing gas. S3. The primary process gas from the incinerator enters the reactor and undergoes a second reaction with the desulfurizing agent in the reactor to obtain secondary process gas and desulfurizing agent to be generated; the second reaction satisfies the following: the sulfur dioxide in the primary process gas is adsorbed by the desulfurizing agent and converted into sulfate; S4. After the desulfurizing agent is output from the reactor, at least a portion of it enters the regenerator for regeneration to obtain regenerated desulfurizing agent; the regenerated desulfurizing agent is returned to the reactor to participate in the second reaction; the secondary process gas from the reactor is treated by heat exchange and washing to obtain purified tail gas.

2. The sulfur recovery process according to claim 1, characterized in that, The process of obtaining sulfur-producing tail gas and liquid sulfur after cooling and single-stage Claus reaction of the primary sulfur-producing process gas includes: the primary sulfur-producing process gas is heated by a waste heat boiler, and then successively cooled and subjected to single-stage Claus reaction to separate the sulfur-producing tail gas and liquid sulfur. And / or, the cooling, single-stage Claus reaction includes: the primary sulfur production process gas, after being output from the waste heat boiler, enters the primary condenser for cooling and separation to obtain secondary sulfur production process gas and liquid sulfur; the secondary sulfur production process gas enters the primary heater and is heated to 210-260°C, then enters the primary converter to undergo the Claus reaction to obtain tertiary sulfur production process gas; the tertiary sulfur production process gas enters the secondary condenser for cooling and separation to obtain sulfur production tail gas and liquid sulfur.

3. The sulfur recovery process according to claim 1 or 2, characterized in that, The first oxygen-containing gas includes air; And / or, the second oxygen-containing gas includes air; And / or, the temperature of the first reaction is 600~750℃; And / or, the temperature of the second reaction is 650~700℃.

4. The sulfur recovery process according to any one of claims 1-3, characterized in that, The secondary process gas from the reactor passes sequentially through a heat exchanger, a waste heat boiler, a steam generator, and a preheater before undergoing the washing treatment. And / or, the second oxygen-containing gas exchanges heat with the secondary process gas flowing through the preheater to obtain preheated oxygen-containing gas; the preheated oxygen-containing gas and the sulfur-producing tail gas enter the incinerator to undergo the first reaction; And / or, after deoxygenated water enters the waste heat boiler and exchanges heat with the secondary process gas flowing through the waste heat boiler, medium-pressure steam is generated; the medium-pressure steam enters the superheater and exchanges heat with the secondary process gas flowing through the superheater.

5. The sulfur recovery process according to claim 4, characterized in that, The washing process includes: after the secondary process gas is output from the preheater, it enters the quenching and washing tower and comes into contact with the washing liquid for quenching and washing to obtain purified tail gas and non-gas phase materials. The non-gas phase material enters the first filter for first solid-liquid separation to obtain first filtrate and recovered desulfurizing agent; the recovered desulfurizing agent is slurried in a slurry tank and enters the reactor; part of the first filtrate enters the second filter for second solid-liquid separation to obtain second filtrate and second filter residue; the second filtrate is cooled by an air cooler and returned to the quench washing tower, and the second filter residue is reused in the catalytic cracking unit.

6. The sulfur recovery process according to any one of claims 1-5, characterized in that, The regeneration process includes: the desulfurizing agent to be recycled entering the regenerator undergoes a regeneration reaction with a reducing agent to obtain the regenerated desulfurizing agent; wherein, the regeneration reaction satisfies the following condition: the sulfur element in the sulfate is reduced by the reducing agent to hydrogen sulfide and / or sulfur dioxide.

7. The sulfur recovery process according to claim 6, characterized in that, The reducing agent includes hydrogen and / or elemental sulfur; And / or, the temperature of the regeneration reaction is 500–630°C.

8. The sulfur recovery process according to any one of claims 1-7, characterized in that, The purified exhaust gas contains ≤1 mg / Nm³ of SO₂ on a dry basis. 3 ; And / or, the dry basis particulate matter content in the purified exhaust gas is ≤30 mg / Nm³. 3 .

9. A sulfur production apparatus, characterized in that, Step S1 for performing the sulfur recovery process according to any one of claims 1-8 includes: a sulfur production furnace, a waste heat boiler, a primary condenser, a primary heater, a primary converter, and a secondary condenser connected in sequence.

10. A desulfurization device, characterized in that, Steps S2 to S4 for performing the sulfur recovery process according to any one of claims 1-8 include: an incinerator, which is provided with a first feed inlet, a second oxygen-containing gas inlet and a primary process gas outlet; The reactor is equipped with a pre-treatment agent circulation inlet, a secondary process gas outlet, a pre-treatment agent outlet, a primary process gas inlet connected to the primary process gas outlet of the incinerator, and a fresh desulfurizing agent inlet. The regenerator is provided with a regenerator outlet connected to the regenerator inlet of the regeneration waste pot, a regenerator inlet connected to the regenerator outlet of the reactor, a regenerator outlet connected to the regenerator circulation inlet of the reactor, and a reducing agent inlet. The regeneration waste pot is provided with a regeneration gas passage; the regeneration gas passage of the regeneration waste pot is connected to the regenerant outlet of the regenerator; The third filter is equipped with a regeneration gas passage and a backflush gas passage; the backflush gas passage of the third filter is connected to the first feed inlet of the incinerator. The sulfur production unit has a secondary condenser with a tertiary sulfur production process gas inlet, a sulfur production tail gas outlet, and a liquid sulfur outlet; the sulfur production tail gas outlet of the secondary condenser is connected to the first feed inlet of the incinerator. The superheater is equipped with a two-stage process gas passage; The waste heat boiler is equipped with a two-stage process gas passage. The steam generator is equipped with a two-stage process gas passage; The preheater is equipped with a two-stage process gas passage; The quench scrubbing tower is provided with a secondary process gas channel, a non-gas phase material channel, and a scrubbing liquid channel; the secondary process gas channel of the superheater, the secondary process gas channel of the waste heat boiler, the secondary process gas channel of the steam generator, the secondary process gas channel of the preheater, and the secondary process gas channel of the quench scrubbing tower are connected in sequence; The slurry tank is provided with a first material inlet, a second material inlet, and a material outlet. The material outlet of the slurry tank is connected to the gas phase section of the reactor. The first material inlet of the slurry tank is connected to the first filter residue outlet of the first filter, and the second material inlet of the slurry tank is connected to the second filtrate outlet of the first filter. The first filter has a non-gas phase material inlet, a first filter residue outlet, a first filtrate outlet, and a second filtrate outlet; the non-gas phase material inlet of the first filter is connected to the non-gas phase material channel of the quench washing tower, the first filter residue outlet of the first filter is connected to the first material inlet of the slurry tank, and the second filtrate outlet of the first filter is connected to the second material inlet of the slurry tank. An air cooler is provided with a washing liquid channel; the washing liquid channel of the air cooler is connected to the washing liquid channel of the washing tower; The second filter is provided with a first filtrate inlet, a second filter residue outlet, and a third filtrate outlet; the first filtrate inlet of the second filter is connected to the first filtrate outlet of the first filter, and the third filtrate outlet of the second filter is connected to the washing liquid channel of the air cooler. The new agent tank is equipped with a fresh desulfurizing agent channel; the fresh desulfurizing agent channel of the new agent tank is connected to the fresh desulfurizing agent inlet of the reactor.

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