CN111495118A - A moving bed type flue gas low temperature adsorption desulfurization device - Google Patents

Abstract

The invention discloses a moving bed type low-temperature flue gas adsorption desulfurization device, which comprises a dedusted flue gas input pipeline, a desulfurized flue gas pipeline, a booster fan, a flue gas waste heat recoverer, a flue gas cooling system, a moving bed adsorption tower and a desorption tower, wherein the dedusted flue gas input pipeline is connected with the booster fan; the flue gas input pipeline after dust removal is communicated with the inlet of a flue gas waste heat recoverer through a booster fan, the outlet of the flue gas waste heat recoverer is communicated with the inlet of a flue gas cooling system, the outlet of the flue gas cooling system is communicated with the flue gas inlet of a moving bed adsorption tower, the porous adsorbent outlet at the bottom of the moving bed adsorption tower is communicated with the inlet of a desorption tower, the porous adsorbent outlet of the desorption tower is communicated with the porous adsorbent inlet at the top of the moving bed adsorption tower, the gas outlet of the moving bed adsorption tower is communicated with the flue gas pipeline after sulfur removal, and the device is used for₂The adsorption capacity is large, the adsorption equipment is small, the loss of the adsorbent is low, and the safety is high.

Description

A moving bed type flue gas low temperature adsorption desulfurization device

technical field

The invention belongs to the technical field of flue gas desulfurization, and relates to a moving bed type flue gas low-temperature adsorption desulfurization device.

Background technique

The flue gas produced by burning coal contains a large amount of SO ₂ , which is one of the main causes of air pollution. At present, the mainstream desulfurization technology of coal-fired flue gas is limestone-gypsum wet desulfurization technology, which removes insoluble calcium sulfate (gypsum) by _reacting SO2 with limestone slurry. Wet desulfurization uses a large amount of limestone as a desulfurizing agent. The large-scale mining of limestone has caused serious damage to the mountain and produced a large amount of desulfurization wastewater, which also brings treatment problems to the power plant.

In addition, activated coke (carbon) dry desulfurization technology is also one of the more mature desulfurization technologies at present, and it is widely used in Japan, Germany and my country. The operating temperature of activated coke (carbon) dry desulfurization technology is generally 100-150 ° C for adsorption. At this temperature, SO ₂ reacts with H ₂ O and O ₂ in the flue gas to generate H ₂ SO ₄ , so the adsorption of SO ₂ It is achieved by chemical adsorption in the form of H ₂ SO ₄ . The adsorbed H ₂ SO ₄ is regenerated by heating to generate high-concentration SO ₂ to produce products such as sulfuric acid or sulfur; or the adsorbed H ₂ SO ₄ is washed out by water washing and regeneration.

The adsorption and heating regeneration mechanism of activated coke (carbon) dry desulfurization is as follows:

Adsorption reaction: SO ₂ +H ₂ O+1/2O ₂ =H ₂ SO ₄

Heating regeneration reaction: 2H ₂ SO ₄ +C→CO ₂ +2SO ₂ +2H ₂ O (main reaction at 350-450℃)

H ₂ SO ₄ +C→CO+SO ₂ +H ₂ O (main reaction above 450℃)

Activated coke (carbon) dry desulfurization technology has the following disadvantages:

1. The sulfur capacity (SO ₂ adsorption capacity) is low, generally less than 30mg/g, the activated coke (carbon) loading capacity is large, and the adsorption equipment is large;

2. The heating regeneration temperature is high, generally higher than 350 °C, the heat consumption is large, and activated coke (carbon) is prone to spontaneous combustion, so the contact with oxygen must be prevented during the regeneration process, and the safety is poor;

3. Activated coke (carbon) participates in the reaction in the heating regeneration process, and the adsorbent is consumed a lot. The regeneration gas contains a large amount of CO ₂ , CO and other gases, which affects the recovery and utilization of SO ₂ .

A conventional activated coke (carbon) dry desulfurization device is shown in Figure 1.

SUMMARY OF THE INVENTION

The purpose of the present invention is to overcome the shortcomings of the above-mentioned prior art, and to provide a moving bed type flue gas low-temperature adsorption desulfurization device, which has a large adsorption capacity for SO ₂ , while the adsorption equipment is small, and the loss of the adsorbent is low, At the same time higher security.

In order to achieve the above purpose, the moving bed type flue gas low-temperature adsorption desulfurization device of the present invention includes a flue gas input pipeline after dedusting, a booster fan, a flue gas waste heat recovery device, a flue gas cooling system, a flue gas pipeline after sulfur, a mobile Bed adsorption tower and desorption tower;

After dedusting, the flue gas input pipeline is connected with the inlet of the flue gas waste heat recovery device through the booster fan, the outlet of the flue gas waste heat recovery device is connected with the inlet of the flue gas cooling system, and the outlet of the flue gas cooling system is connected with the inlet of the moving bed adsorption tower. The inlet of the flue gas is connected, the outlet of the porous adsorbent at the bottom of the moving bed adsorption tower is connected with the inlet of the desorption tower, the outlet of the porous adsorbent of the desorption tower is connected with the inlet of the porous adsorbent at the top of the moving bed adsorption tower, and the outlet of the porous adsorbent of the moving bed adsorption tower is connected. The gas outlet is communicated with the flue gas pipeline after sulfur.

The flue gas cooling system adopts a two-stage spray cooling structure.

The flue gas cooling system adopts a three-stage spray cooling structure.

The porous adsorbent outlet of the desorption tower is communicated with the porous adsorbent inlet at the top of the moving bed adsorption tower through the chain bucket lifting device.

Porous adsorbents are activated coke or molecular sieves.

During operation, the high-temperature flue gas after dust removal is sent to the flue gas waste heat recovery device through the booster fan, and the flue gas temperature is reduced to below 70 ℃ through the flue gas waste heat recovery device. The recovered heat is used to supply hot water, Steam or used for refrigeration, the flue gas after the waste heat recovery enters the flue gas cooling system, and is cooled to the temperature area below room temperature by spray cooling or indirect heat exchange, among which, the cooling in the temperature area above room temperature is taken away by cooling water The cooling method is adopted for cooling in the temperature area below room temperature; the cooled flue gas enters into the moving bed adsorption tower, and through contact with the porous adsorbent loaded in the moving bed adsorption tower, the flue gas is removed by physical adsorption. The SO ₂ , then enters into the flue gas pipeline after sulfur, and the porous adsorbent saturated with adsorption is discharged from the bottom of the moving bed adsorption tower by self-weight blanking, and enters the desorption tower, and in the desorption tower, by heating or By means of vacuuming, the porous adsorbent saturated with adsorption is regenerated, and SO ₂ gas is desorbed; the porous adsorbent after desorption is sent to the top of the moving bed adsorption tower for repeated use.

The present invention has the following beneficial effects:

During specific operation, the moving bed type flue gas low-temperature adsorption desulfurization device of the present invention cools the flue gas through the flue gas waste heat recovery device and the flue gas cooling system, so that the adsorption temperature of SO ₂ is low, the adsorption capacity is large, and the adsorbent The loading amount is small, the circulation amount of the adsorbent in the moving bed adsorption tower is low, and the adsorption equipment is small. In addition, the present invention adopts the method of physical adsorption, which is easy to desorb, has low desorption temperature, and low heat consumption, and the adsorbent is not easy to spontaneously ignite and has high safety. , it can be desorbed by vacuum suction. At the same time, the adsorbent does not participate in the reaction during the desorption process, and the adsorbent is almost not lost, and it can run continuously without adsorbent supplementation. In addition, a large amount of acidic condensate water precipitated during the cooling process of the flue gas can be used by the power plant after neutralization treatment, reducing the water consumption of the power plant, and can be widely used in flue gas such as power plant flue gas, steel mill sintering flue gas and coke oven flue gas. Desulfurization.

Description of drawings

Fig. 1 is the structural representation of the prior art;

FIG. 2 is a schematic structural diagram of the present invention.

Among them, 1 is a booster fan, 2 is a flue gas waste heat recovery device, 3 is a flue gas cooling system, 4 is a moving bed adsorption tower, and 5 is a desorption tower.

Detailed ways

Below in conjunction with accompanying drawing, the present invention is described in further detail:

2, the moving bed type flue gas low-temperature adsorption desulfurization device according to the present invention includes a flue gas input pipeline after dedusting, a booster fan 1, a flue gas waste heat recovery device 2, a flue gas cooling system 3, a moving bed adsorption tower 4, The desorption tower 5 and the flue gas pipeline after the sulfur; the flue gas input pipeline after dedusting is connected with the inlet of the flue gas waste heat recovery device 2 through the booster fan 1, and the outlet of the flue gas waste heat recovery device 2 is connected with the inlet of the flue gas cooling system 3 The outlet of the flue gas cooling system 3 is communicated with the flue gas inlet of the moving bed adsorption tower 4, the porous adsorbent outlet at the bottom of the moving bed adsorption tower 4 is communicated with the inlet of the desorption tower 5, and the porous adsorbent outlet of the desorption tower 5 is communicated with each other. It is communicated with the porous adsorbent inlet at the top of the moving bed adsorption tower 4, and the gas outlet of the moving bed adsorption tower 4 is communicated with the flue gas pipeline after sulfur.

The porous adsorbent outlet of the desorption tower 5 is communicated with the porous adsorbent inlet at the top of the moving bed adsorption tower 4 through the chain bucket lifting device; the porous adsorbent is activated coke or molecular sieve.

During operation, the high-temperature flue gas after dust removal is sent to the flue gas waste heat recovery device 2 through the booster fan 1, and the flue gas temperature is reduced to below 70°C through the flue gas waste heat recovery device 2, wherein the recovered heat is used for supply Hot water, steam or used for refrigeration, the flue gas after the waste heat recovery enters the flue gas cooling system 3, and is cooled to the temperature area below room temperature by spray cooling or indirect heat exchange, wherein, the temperature area above room temperature is cooled through The cooling water takes away the heat, and the cooling method is adopted for cooling in the temperature area below room temperature; the cooled flue gas enters the moving bed adsorption tower 4, and through the contact with the porous adsorbent loaded in the moving bed adsorption tower 4, through the physical adsorption. The SO ₂ in the flue gas is removed by the method, and then enters the flue gas pipeline after sulfur, and the porous adsorbent saturated with adsorption is discharged from the bottom of the moving bed adsorption tower 4 by self-weight blanking, and enters the desorption tower 5. In the desorption tower 5, the porous adsorbent saturated with adsorption is regenerated by heating or vacuuming to desorb the SO gas _; the porous adsorbent after the desorption is completed is sent to the top of the moving bed adsorption tower 4 for repeated use .

Example 1

The flue gas of the 600MW coal-fired unit (flue gas flow rate of 2 million standard cubic meters/hour, SO ₂ content of 3000 mg/Nm ³ ) enters the present invention after denitration and dust removal. Waste heat recovery device 2, the flue gas temperature is reduced from 120 ℃ to 70 ℃, and hot water at 80-90 ℃ is generated at the same time, which enters the heating pipe network; flue gas at 70 ℃ enters the flue gas cooling system 3, and is cooled by spraying When the temperature drops to 5°C, the flue gas cooling system 3 adopts a two-stage spray cooling method. The first stage is cooled to 35°C by spraying, the second stage is cooled to 5°C by chilled water spraying, and the first stage is sprayed with circulating liquid through The cooling water is cooled, and the second-stage spray circulating liquid is cooled by the chiller; the low-temperature flue gas cooled to 5°C through the flue gas cooling system 3 enters the moving bed adsorption tower 4, and the moving bed adsorption tower 4 adopts a cross-flow method. The flue gas passes through the adsorption bed horizontally, and the activated coke adsorbent flows vertically through the moving bed adsorption tower 4 from top to bottom. After the flue gas flows through the moving bed adsorption tower ₄ , the SO2 in the flue gas is adsorbed by the activated coke, and the clean flue gas is discharged from the moving bed adsorption tower 4. The activated coke saturated with adsorption is discharged from the bottom of the moving bed adsorption tower 4, and enters the desorption tower 5 by self-weight blanking. Under the hot air purging of ℃, the high concentration SO ₂ desorption gas is desorbed, and the lower section is the cooling section. The bottom of the tower is discharged, and then it is pulled up to the top of the moving bed adsorption tower 4 through the chain bucket lifting device to form a closed cycle and run continuously.

During the whole moving bed cycle, the feeding and discharging rates of the moving bed adsorption tower 4 and the desorption tower 5 are kept the same, and the active coke flow rate is controlled by the star discharger at the bottom of the desorption tower 5. The residual SO ₂ concentration in the net flue gas discharged from the moving bed adsorption tower 4 is adjusted by adjusting the active coke flow rate. When the concentration exceeds the standard, the active coke flow rate needs to be increased. At 5 °C adsorption desulfurization, the saturated sulfur capacity is about 80mg/ g, the active coke loading capacity of the moving bed adsorption tower 4 is 300 tons, and the active coke circulating capacity is 75 tons/hour.

Embodiment 2

The overall operation process of the second embodiment is the same as that of the first embodiment. The difference is that the flue gas cooling system 3 adopts a three-stage spray cooling method to cool the 70°C flue gas after waste heat recovery to -20°C, and the first stage is sprayed Cool down to 35°C, the second stage is cooled to 5°C by chilled water spray, the third stage is cooled to -20°C by low-temperature calcium chloride solution spray, the first stage is cooled by cooling water, the second stage is cooled by cooling water The spray circulating fluid is cooled by the chiller; the third-stage spray circulating fluid (calcium chloride solution) is cooled by the low temperature refrigeration unit. The flue gas cooled to -20°C enters the moving bed adsorption tower 4 for low temperature SO ₂ adsorption. The activated coke desorption regeneration process is the same as that of the first embodiment, the active coke discharge and feeding cycle are the same as those of the first embodiment, and the difference between the second embodiment and the first embodiment is that the adsorption temperature is lower and the adsorption capacity is larger, so the activated coke filling At the same time, the energy consumption of flue gas cooling is larger, and the saturated sulfur capacity is about 170 mg/g at -20 °C adsorption desulfurization, and the active coke filling capacity of moving bed adsorption tower 4 It is 150 tons, and the active coke circulation rate is 35 tons/hour.

Claims (4)

1. A moving bed type low-temperature flue gas adsorption desulfurization device is characterized by comprising a flue gas input pipeline after dust removal, a booster fan (1), a flue gas waste heat recoverer (2), a flue gas cooling system (3), a moving bed adsorption tower (4), a desorption tower (5) and a flue gas pipeline after desulfurization;

the dedusted flue gas input pipeline is communicated with an inlet of a flue gas waste heat recoverer (2) through a booster fan (1), an outlet of the flue gas waste heat recoverer (2) is communicated with an inlet of a flue gas cooling system (3), an outlet of the flue gas cooling system (3) is communicated with a flue gas inlet of a moving bed adsorption tower (4), a porous adsorbent outlet at the bottom of the moving bed adsorption tower (4) is communicated with an inlet of a desorption tower (5), a porous adsorbent outlet of the desorption tower (5) is communicated with a porous adsorbent inlet at the top of the moving bed adsorption tower (4), and a gas outlet of the moving bed adsorption tower (4) is communicated with a flue gas pipeline after sulfur removal;

the flue gas cooling system (3) adopts a two-section type spray cooling structure or a three-section type spray cooling structure.

2. The moving bed type flue gas low-temperature adsorption desulfurization device according to claim 1, characterized in that the porous adsorbent outlet of the desorption tower (5) is communicated with the porous adsorbent inlet at the top of the moving bed adsorption tower (4) through a bucket chain lifting device.

3. The moving bed type low temperature flue gas adsorption desulfurization device of claim 1, wherein the porous adsorbent is activated coke or molecular sieve.

4. The moving bed type low-temperature flue gas adsorption desulfurization device of claim 1, wherein, in operation, the dedusted high-temperature flue gas is sent into a flue gas waste heat recoverer (2) through a booster fan (1), the flue gas temperature is reduced to below 70 ℃ through the flue gas waste heat recoverer (2), wherein the recovered heat is used for supplying hot water, steam or refrigerating, the flue gas subjected to waste heat recovery enters a flue gas cooling system (3), and is cooled to a temperature zone below room temperature through a spray cooling or indirect heat exchange mode, wherein the temperature zone above the room temperature takes away the heat through cooling water, and the temperature zone below the room temperature is cooled by adopting a refrigerating mode; the cooled flue gas enters a moving bed adsorption tower (4), contacts with a porous adsorbent filled in the moving bed adsorption tower (4), and removes SO in the flue gas in a physical adsorption mode₂Then the sulfur-containing porous adsorbent enters a sulfur-containing flue gas pipeline to be communicated, the porous adsorbent saturated in adsorption is discharged from the bottom of a moving bed adsorption tower (4) in a self-weight blanking mode, enters a desorption tower (5) and is desorbedIn the absorption tower (5), the porous adsorbent saturated in absorption is regenerated by heating or vacuumizing, and SO is desorbed₂A gas; and the porous adsorbent after desorption is sent to the top of the moving bed adsorption tower (4) for repeated use.

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