CN115672005A - Power plant flue gas desulfurization and dust removal system and process - Google Patents
Power plant flue gas desulfurization and dust removal system and process Download PDFInfo
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Abstract
The invention discloses a power plant flue gas desulfurization and dust removal system and a process, wherein the power plant flue gas desulfurization and dust removal system comprises a desulfurization absorption tower system, a bag-type dust remover system, a desulfurization ash discharge system, a material circulation system, a process water system and a desulfurizer preparation and supply system; by adopting the power plant flue gas desulfurization dust removal system to carry out desulfurization and dust removal on the flue gas of the power plant after denitration treatment, the desulfurization dust removal effect is good, the whole system is strong in stability, high in reliability and high in desulfurizer utilization rate, the environmental pollution can be reduced, and the requirements of flue gas desulfurization and dust removal are well met.
Description
Technical Field
The invention belongs to the technical field of atmospheric desulfurization and dust removal, and particularly relates to a flue gas desulfurization and dust removal system and process for a power plant.
Background
A large amount of flue gas generated in the power generation process of a power plant has complex components, wherein the sulfur dioxide content is highest, the harm is greatest, and the flue gas is a main reason for forming acid rain; besides, the smoke is also doped with considerable dust, and the dust with smaller particle size is one of the main causes of haze. Under the strict requirements of national policy, the flue gas of a power plant needs to be ultralow in emission, so that the pollution of the flue gas to the environment is reduced, the flue gas needs to be correspondingly desulfurized before being emitted, dust in the flue gas also needs to be treated, and the pollution caused by the flue gas is reduced to the maximum extent.
The flue gas of a power plant mostly adopts a method for respectively treating dust removal and desulfurization, wherein the dust removal method comprises electrostatic dust removal, bag type dust removal, electric bag composite dust removal technology and the like, the desulfurization method comprises limestone-gypsum wet flue gas desulfurization, rotary spray semi-dry flue gas desulfurization, seawater flue gas desulfurization, in-furnace calcium spraying tail humidification desulfurization, electron beam flue gas desulfurization, circulating fluidized bed boiler desulfurization and the like, and the methods have the advantages and the disadvantages that the electrostatic dust removal is very sensitive to the properties (components, particle size, density, specific resistance, adhesiveness and the like) of fly ash, the requirements on manufacturing, installation and operation levels are high, the bag type dust removal is in a high-temperature, high-humidity and high-corrosivity gas environment, the dust removal adaptability is poor, the filter bag is easy to damage and fall off, and the old bag is difficult to recycle, the electric bag composite dust removal technology is compatible with the advantages of electrostatic dust removal and bag type dust removal, but still has the defects of ozone corrosion, high operation resistance, large investment, large floor area, and the like, besides, the filter bag replacement cost is still high and the problems need to be considered, and other new dust removal technologies are broken through some improvements; limestone-gypsum wet flue gas desulfurization occupies large area, and has high investment and high station power consumption, and in addition, equipment has certain scaling phenomenon, and the corrosion resistance aspect needs to be further enhanced; the rotary spraying semi-dry flue gas desulfurization process has the problems of large limestone consumption, low utilization rate of a desulfurizer, incapability of recycling desulfurized byproducts and the like; the seawater flue gas desulfurization process has low desulfurization efficiency and has certain influence along with the sea environment; the tail humidifying and desulfurizing process of calcium spraying in the boiler needs to change the boiler, and can generate certain influence on the operation of the boiler; the electron beam flue gas desulfurization process depends on an electron beam accelerator to generate high-energy electrons, needs a high-power electron gun and is harmful to human bodies, so that radiation protection shielding is needed, and the operation and maintenance requirements are high; in the desulfurization process of the circulating fluidized bed boiler, the heating surface of a flue at the tail part of a boiler part is easy to wear, leak air and the like; therefore, from the aspects of treatment efficiency, operation and maintenance and cost consumption, the flue gas is treated by a single method, and the requirements of flue gas desulfurization and dust removal cannot be well met.
In view of the above circumstances, a new flue gas desulfurization and dust removal system and process are urgently needed to be researched in the industry, so that the desulfurization and dust removal effect is good, the whole system is strong in stability, high in reliability and high in desulfurizer utilization rate, the environmental pollution can be reduced, and the requirements of flue gas desulfurization and dust removal are well met.
Disclosure of Invention
Aiming at the defects in the prior art, the invention aims to provide the flue gas desulfurization and dust removal system and the process for the power plant, which not only have good desulfurization and dust removal effects, but also have strong stability, high reliability and high desulfurizer utilization rate of the whole system, can reduce environmental pollution and well meet the requirements of flue gas desulfurization and dust removal.
In order to achieve the purpose, the invention adopts the following technical scheme:
the invention provides a power plant flue gas desulfurization and dust removal system, which comprises a desulfurization absorption tower system, a bag-type dust remover system, a desulfurization ash discharge system, a material circulating system, a process water system and a desulfurizer preparation and supply system;
the bottom of the desulfurization absorption tower system is provided with a flue inlet, and the top of the desulfurization absorption tower system is provided with a flue outlet; the desulfurization absorption tower system comprises an inlet section, a tower bottom ash discharge device, a Venturi acceleration section, a circulating fluidized bed reaction section and a top circulating outlet section from bottom to top in sequence;
the air inlet of the bag-type dust collector system is connected with the flue outlet of the desulfurization absorption tower system;
the desulfurization ash discharging system is connected with the bag-type dust collector system;
one end of the material circulating system is connected with an ash bucket of the bag-type dust collector system, and the other end of the material circulating system is connected with the desulfurization absorption tower system;
the backflow type nozzle of the process water system is arranged at the inlet section of the desulfurization absorption tower system;
and the feeding chute of the desulfurizer preparation supply system is connected with the desulfurization absorption tower system.
Preferably, the flue inlet and the flue outlet are both provided with temperature and pressure measurement systems.
Preferably, the bag-type dust collector system comprises an inlet smoke box, a smoke chamber connected with the inlet smoke box, a gas purification chamber connected with the smoke chamber, an outlet smoke box connected with the gas purification chamber, a low-pressure pulse ash removal device arranged above the gas purification chamber, an ash bucket arranged below the purification chamber, an outlet smoke box connected with the gas purification chamber and an electric control device;
and a filtering cloth bag is arranged in the air purifying chamber, and is prepared from a PPS (polyphenylene sulfite) filtering material subjected to PTFE (polytetrafluoroethylene) impregnation surface treatment.
Preferably, the desulfurized ash discharge system comprises an aeration tank and a pneumatic conveying bin pump connected with the aeration tank; the inflation box is connected with an ash bucket of the bag-type dust collector system, and a pneumatic flow shutoff valve is arranged between the inflation box and the pneumatic conveying bin pump;
the pneumatic conveying bin pump adopts a down-leading bin pump, and a feed valve and a discharge valve of the pneumatic conveying bin pump adopt bimetallic gate valves; an automatic blockage cleaning device is arranged in the pneumatic conveying bin pump; and the pneumatic conveying bin pump is connected to the desulfurization ash bin through a conveying pipeline.
Preferably, the material circulating system comprises an ash bucket fluidization fan, an air chute fluidization fan arranged on the air chute, a fluidization fan heater connected with the ash bucket fluidization fan and the air chute fluidization fan, and the pneumatic flow control valve arranged on the air chute;
the ash bucket fluidization fan is arranged at an ash outlet of an ash bucket of the bag-type dust collector system;
one end of the air chute is connected with the ash bucket fluidization fan, and the other end of the air chute is connected with an inlet section of the desulfurization absorption tower system.
Preferably, the process water system comprises a process water tank, a high-pressure water pump connected with the process water tank, an atomizing spray gun connected with the high-pressure water pump, and an adjusting device for adjusting the water spraying quantity of the atomizing spray gun;
the backflow nozzle is arranged on the atomizing spray gun; the spray gun body of the atomization spray gun is made of stainless steel, and the backflow type nozzle is made of tungsten carbide.
Preferably, the desulfurizer preparation and supply system comprises a quicklime powder tanker, a quicklime bin connected with the quicklime powder tanker, a slaked lime bin connected with the quicklime bin, a slaked lime feeding device arranged at the bottom of the slaked lime bin and a feeding chute connected with the slaked lime feeding device;
the feeding chute is arranged at the inlet section of the desulfurization absorption tower system.
The second aspect of the invention provides a power plant flue gas desulfurization and dust removal process, which is processed by the power plant flue gas desulfurization and dust removal system of the first aspect of the invention, and comprises the following steps:
(1) The flue gas after denitration treatment enters a desulfurization absorption tower system for desulfurization treatment, and after the flue gas is mixed with process water and a desulfurizing agent for desulfurization, the desulfurized flue gas is discharged from a flue outlet of the desulfurization absorption tower system;
(2) After the desulfurization flue gas is dedusted by the bag-type dust remover system, a part of desulfurization ash is discharged by the desulfurization ash discharge system, and the rest of desulfurization ash returns to the bottom of the desulfurization absorption tower system through the material circulating system to continue desulfurization reaction.
Preferably, in the step (1), the denitration treatment adopts an SNCR/SCR mixed process; and/or
In the desulfurization treatment process, the smoke gas amount in the bag-type dust collector system is 670000-940000 Nm 3 The temperature of the flue gas is 80-162 ℃; and/or
The pressure drop of the desulfurization absorption tower system is 300-2200 Pa, and the calcium-sulfur ratio is 1.2-1.6 mol/mol; and/or
The desulfurizer adopts slaked lime, the water content is lower than 1.5 percent, and the specific surface area is more than 15m 2 (ii)/g; and/or
The residence time of the desulfurizer is 6 to 158s; and/or
The inlet temperature of the flue gas is 158-172 ℃, the outlet temperature is 82-112 ℃, and the flow rate is 5-7 m/s; and/or
The desulfurization efficiency of the desulfurization treatment is 85-96%.
Preferably, in the step (2), before the dust removal treatment, the dust concentration of the desulfurized flue gas is 620 to 1100mg/Nm 3 The dust concentration in the clean flue gas after dust removal treatment is less than 5mg/Nm 3 。
The invention has the beneficial effects that:
the power plant flue gas desulfurization and dust removal system and the process provided by the invention have the advantages that the desulfurization and dust removal effect is good, the whole system is strong in stability, high in reliability and high in desulfurizer utilization rate, the environmental pollution can be reduced, and the requirements of flue gas desulfurization and dust removal are well met; the following effects are also provided:
1. according to the power plant flue gas desulfurization and dust removal system and the process, in the desulfurization process, industrial water is atomized by the backflow nozzle and then sprayed into the absorption tower, and is mixed with flue gas in the absorption tower at a high mass transfer rate, so that the effect of activating reaction ions is achieved, meanwhile, the temperature in the tower is reduced, the reaction is promoted to be carried out, and the desulfurization efficiency is not lower than 85%;
2. according to the power plant flue gas desulfurization and dust removal system and the process, in the dust removal process, an uninterrupted rotary mortgage pulse ash removal mode is adopted, the number of pulse valves is reduced, and the maintenance workload is reduced;
3. the power plant flue gas desulfurization and dust removal system and the process establish stable material circulation through the material circulation system and reduce the consumption of the desulfurizer so as to meet the requirement of power plant flue gas desulfurization.
Drawings
Other features, objects and advantages of the invention will become more apparent upon reading of the detailed description of non-limiting embodiments with reference to the following drawings:
FIG. 1 is a schematic structural diagram of a flue gas desulfurization and dust removal system of a power plant.
Detailed Description
In order to better understand the technical solutions of the present invention, the following further describes the technical solutions of the present invention with reference to the accompanying drawings and examples.
Referring to fig. 1, the power plant flue gas desulfurization and dust removal system provided by the invention comprises a desulfurization absorption tower system 1, a bag-type dust remover system 2, a desulfurization ash discharge system 6, a material circulation system 5, a process water system 3 and a desulfurizer preparation and supply system 4; the flue gas after denitration treatment enters a desulfurization absorption tower system 1 from the bottom, passes through a bag-type dust collector system 2 after desulfurization and is discharged to a chimney by an induced draft fan, wherein the temperature of the flue gas is 80-162 ℃ and the treatment capacity of the flue gas is 670000-940000 Nm 3 /h。
Referring to fig. 1, a flue inlet is arranged at the bottom of the desulfurization absorption tower system 1, and a flue outlet is arranged at the top of the desulfurization absorption tower system; the desulfurization absorption tower system 1 is composed of an inlet section, a tower bottom ash discharge device, a Venturi acceleration section, a circulating fluidized bed reaction section and a top circulating outlet section from bottom to top in sequence, the whole desulfurization absorption tower system adopts a steel body structure, a flue inlet and a flue outlet are respectively provided with a temperature and pressure measuring system, flue gas enters from the bottom of the desulfurization absorption tower system 1 through the flue inlet, and is mixed with process water and a desulfurizing agent to react in the tower, and the desulfurized flue gas is discharged from the flue outlet at the top.
Referring to fig. 1, an air inlet of a bag-type dust collector system 2 is connected with a flue outlet of a desulfurization absorption tower system 1; the desulfurization ash discharging system 6 is connected with the bag-type dust collector system 2; the bag-type dust collector system 2 is provided with an ash hopper, a smoke chamber, a gas purifying chamber, an inlet smoke box, an outlet smoke box, a low-pressure pulse ash removal device, an electric control device and the like; wherein the inlet smoke box is provided with an air inlet which is connected with the smoke chamberThe flue gas chamber, the air purifying chamber and the outlet flue box are sequentially connected, a low-pressure pulse ash removal device is arranged above the air purifying chamber, an ash bucket is arranged below the air purifying chamber, and the electric control device controls the bag-type dust remover system 2 to carry out dust removal treatment; the ash bucket adopts a ship-shaped stock bin; the air purifying chamber is internally provided with a filtering cloth bag which is prepared by a PPS filtering material after PTFE immersion surface treatment, and the stability and the reliability are strong. The low-pressure pulse ash removal device adopts a low-pressure pulse ash removal mode (compressed air for ash removal is 0.09 MPa), and a Roots blower is used for providing ash removal air; the dust concentration of the desulfurized flue gas at the air inlet of the bag-type dust collector system 2 is 620-1100 mg/Nm 3 The dust concentration in the clean flue gas treated by the bag-type dust collector system 2 is less than 5mg/Nm 3 。
Referring to fig. 1, the desulfurization ash discharge system 6 mainly discharges a small part of the desulfurization ash in the bag-type dust collector system 2 to the desulfurization ash storage; the desulfurization ash discharging system 6 comprises an inflation box and a pneumatic conveying bin pump connected with the inflation box; the inflation box is connected with the ash bucket of the bag-type dust collector system 2, and a pneumatic flow shutoff valve is arranged between the inflation box and the pneumatic conveying bin pump; the pneumatic conveying bin pump adopts a downward-leading bin pump, and a feeding valve and a discharging valve of the pneumatic conveying bin pump adopt bimetallic gate valves; an automatic blockage cleaning device is arranged in the pneumatic conveying bin pump; the pneumatic conveying bin pump is connected to the desulfurization ash bin through a conveying pipeline; the desulfurized ash from the bag-type dust collector system 2 enters a pneumatic conveying bin pump through an inflation box and a pneumatic flow shutoff valve and is discharged to a desulfurized ash storehouse through an ash conveying pipeline, wherein the conveying pressure (starting end) of the desulfurized ash conveying bin pump is 0.4-0.6 MPa, and the ash/gas ratio is 26-42 kg/Nm 3 。
Referring to fig. 1, one end of a material circulating system 5 is connected with an ash bucket of a bag-type dust collector system 2, and the other end is connected with a desulfurization absorption tower system 1; the material circulating system 5 comprises an ash bucket fluidization fan, an air chute fluidization fan, a fluidization fan heater, a pneumatic flow control valve and the like, wherein the ash bucket fluidization fan is arranged at an ash outlet of an ash bucket of the bag-type dust collector system 2; one end of the air chute is connected with the ash bucket fluidization fan, and the other end of the air chute is connected with the inlet section of the desulfurization absorption tower system 1; the air chute fluidizing fan is arranged on the air chute and is used for discharging the substances in the air chuteThe material provides power; the fluidization fan heater is connected with the ash bucket fluidization fan and the air chute fluidization fan; the pneumatic flow control valve is arranged on the air chute, and the opening of the pneumatic flow control valve is adjusted through pressure drop adjustment in the desulfurization absorption tower system 1, so that the circulating amount of the desulfurization ash of the material circulating system 5 is controlled; the desulfurization ash in the ash bucket of the bag-type dust collector system 2 is circulated back to the desulfurization absorption tower system 1 in a mode of adding an air chute into a ship-shaped bin for cyclic utilization, the strength, the smoothness and the gradient of a fluidization plate used in the material circulating system 5 meet the requirements of smooth circulation of a flow field and materials, and the vulcanization canvas and the sealing material used in the material circulating system 5 are made of original imported materials. In the process of desulfurization and dust removal, the flow of a fluidized fan of an ash bucket of the dust remover is 42-49 Nm 3 Min, total pressure is 57.2-59.3 kPa; the flow rate of the air chute fluidizing fan is 4610-7376 Nm 3 The total pressure is 11596-11717 kPa for min.
Referring to fig. 1, a reflux nozzle of a process water system 3 is provided at an inlet section of a desulfurization absorption tower system 1; the feeding chute of the desulfurizer preparation supply system 4 is connected with the desulfurization absorption tower system 1; the process water system 3 comprises a process water tank, a high-pressure water pump, an atomizing spray gun, an adjusting device and the like; the process water tank is connected with the high-pressure water pump, the atomization spray gun is connected with the high-pressure water pump, and the adjusting device is used for atomizing the water spraying quantity of the spray gun; wherein, the atomizing spray gun is provided with a backflow nozzle which is arranged at the inlet section of the desulfurization absorption tower system 1; the gun body of the atomizing spray gun is made of stainless steel, and the backflow nozzle is made of tungsten carbide; the adjusting device can adopt a backflow adjusting valve. The process water is sprayed into the desulfurization absorption tower system 1 from the process water system 3, and is mixed with the flue gas at a higher mass transfer speed, so that the effects of activating reaction ions and reducing the temperature in the tower are achieved, and the reaction is promoted to be carried out. The water amount of the process water sprayed into the desulfurization absorption tower system 1 is controlled by the outlet temperature of the desulfurization absorption tower system 1, the process water is injected into the desulfurization absorption tower system 1 through a high-pressure water pump by two backflow nozzles, and the opening of the backflow regulating valve is automatically regulated by the backflow nozzles according to the outlet temperature of the desulfurization absorption tower system 1 so as to regulate the backflow water amount of the process water, thereby controlling the water spraying amount of the desulfurization absorption tower system 1 and stably controlling the outlet temperature of the desulfurization absorption tower system 1 at the level required by the process; in addition, the backflow nozzle is installed at the inlet section of the desulfurization absorption tower system 1, so that online adjustment, replacement and maintenance are facilitated.
Referring to fig. 1, the desulfurizer preparation and supply system 4 uses slaked lime as a desulfurizer, so the desulfurizer preparation and supply system 4 comprises a quicklime powder tanker, a quicklime bin, a slaked lime feeding device and a feeding chute; wherein the quicklime powder tanker is connected with a quicklime bin, the quicklime bin is connected with a slaked lime bin, the bottom of the slaked lime bin is provided with a slaked lime feeding device, one end of the feeding chute is connected with the slaked lime feeding device, and the other end of the feeding chute is connected to the inlet section of the desulfurizer preparation and supply system 4; the bottom of the quicklime bin is provided with a quicklime weighing dosing device and a quicklime dry-type slaking device for slaking quicklime, wherein the quicklime dry-type slaking device can adopt a three-level dry slaker; the quicklime bin and the slaked lime bin are both made of steel structures, and the volumes of the quicklime bin and the slaked lime bin are respectively 100m 3 And 120m 3 The 17-day dosage and the 3-day dosage of the desulfurization absorption tower system can be respectively satisfied; the process of the desulfurizer preparation and supply system 4 comprises the following steps: the quicklime powder tanker → the quicklime bin → the three-level dry digester → the pneumatic conveying → the slaked lime bin → the slaked lime feeding device → the feeding chute → the desulfurization absorption tower system 1; in the desulfurization and dust removal process, after quicklime in a powder tanker enters a quicklime bin, slaked lime obtained after digestion enters the slaked lime bin through a rotary feeder and pneumatic transmission (olefinic phase pneumatic transmission can be adopted), enters a feeding chute through a slaked lime feeding device arranged at the bottom of the slaked lime bin, and is fed into an inlet section of a desulfurization absorption tower system 1 through the feeding chute; wherein the slaked lime is based on SO in the desulfurization absorption tower system 1 2 The rotating speed of the slaked lime feeding device is adjusted so as to control the feeding amount of the slaked lime, wherein the slaked lime is dry powder, the water content is 1.1 percent, and the specific surface area is 23m 2 /g。
Based on the power plant flue gas desulfurization and dust removal system, the process for performing desulfurization and dust removal treatment on the power plant flue gas comprises the following steps:
(1) The flue gas after denitration treatment enters a desulfurization absorption tower system for desulfurization treatment, and is discharged from a flue outlet of the desulfurization absorption tower system after being mixed with process water and a desulfurizer for desulfurization;
the specific process is as follows: the flue gas of the power plant is denitrated by an SNCR/SCR mixing process, enters a desulfurization absorption tower system from the bottom, is fully mixed with a desulfurizer and process water and generates desulfurization reaction, and in the process, the desulfurizer adopts slaked lime, the water content of the desulfurizer is lower than 1.5 percent, and the specific surface area of the desulfurizer is more than 15m 2 (ii)/g; the pressure drop of the desulfurization absorption tower system is 300-2200 Pa, and the calcium-sulfur ratio is 1.2-1.6 mol/mol; the residence time of the desulfurizer is 6 to 158s; in addition, the inlet temperature of the flue gas is controlled to be 158-172 ℃, the outlet temperature is controlled to be 82-112 ℃, and the flow speed is controlled to be 5-7 m/s; the desulfurization efficiency in the process reaches 85-96%; after the flue gas after denitration treatment is treated by a desulfurization absorption tower system, the desulfurization flue gas is discharged from a flue outlet of the desulfurization absorption tower system; the temperature of the flue gas in the desulfurization absorption tower system in the desulfurization treatment process is 152 ℃, and the flue gas treatment capacity is 910000Nm 3 /h。
(2) After the desulfurization flue gas is dedusted by the bag-type dust remover system, a part of desulfurization ash is discharged by the desulfurization ash discharge system, and the rest is returned to the bottom of the desulfurization absorption tower system through the material circulating system to continue desulfurization reaction.
The specific process is as follows: the desulfurized flue gas enters a bag-type dust remover system for dust removal, and the clean flue gas after dust removal treatment is discharged to a chimney through a draught fan; most of the desulfurized ash collected in the ash bucket returns to the bottom of the desulfurization absorption tower system through the material circulating system, is mixed with the flue gas subjected to denitration treatment and is subjected to desulfurization treatment continuously, and a small part of desulfurized ash is transferred to a desulfurized ash storehouse through an ash conveying pipeline by a desulfurized ash discharging system; wherein the dust concentration of the desulfurized flue gas obtained in the step (1) is 620-1100 mg/Nm 3 The dust concentration in the clean flue gas after dust removal treatment is less than 5mg/Nm 3 (ii) a The conveying pressure (initial end) of a pneumatic conveying bin pump of a desulfurization ash discharging system in the dust removing process is 0.4-0.6 MPa, and the ash/gas ratio is 26-42 kg/Nm 3 。
The flue gas desulfurization and dust removal system and process of the power plant are further described by combining specific examples; wherein the power plant flue gas desulfurization and dust removal process adopts the power plant flue gas desulfurization and dust removal system; the power plant flue gas desulfurization and dust removal system comprises a desulfurization absorption tower system, a bag-type dust remover system, a desulfurization ash discharge system, a material circulating system, a process water system and a desulfurizer preparation and supply system; the flue gas after denitration treatment enters a desulfurization absorption tower system from the bottom, passes through a bag-type dust collector system after desulfurization and is discharged to a chimney by a draught fan; and discharging a part of the desulfurized ash after the dust removal treatment through a desulfurized ash discharge system, and returning the rest part of the desulfurized ash to the bottom of the desulfurization absorption tower system through a material circulating system to continue the desulfurization reaction.
Example 1
The power plant flue gas desulfurization and dust removal process in the embodiment comprises the following steps:
(1) The flue gas of the power plant enters a desulfurization absorption tower system from the bottom after being subjected to denitration treatment by an SNCR/SCR mixed process, is fully mixed with a desulfurizing agent and process water and undergoes desulfurization reaction, and in the process, the desulfurizing agent adopts slaked lime, the water content of the desulfurizing agent is 1.1 percent, and the specific surface area of the desulfurizing agent is 23m 2 (ii)/g; the pressure drop of the desulfurization absorption tower system is 1550Pa, and the calcium-sulfur ratio is 1.3mol/mol; the residence time of the desulfurizing agent is 45s; in addition, the inlet temperature of the flue gas is controlled to be 166 ℃, the outlet temperature is controlled to be 109 ℃, and the flow speed is controlled to be 7m/s; the desulfurization efficiency in the process reaches 91 percent; after the flue gas after denitration treatment is treated by a desulfurization absorption tower system, the desulfurization flue gas is discharged from a flue outlet of the desulfurization absorption tower system; the temperature of the flue gas in the desulfurization absorption tower system in the desulfurization treatment process is 152 ℃, and the flue gas treatment capacity is 910000Nm 3 /h，
(2) The desulfurized flue gas enters a bag-type dust collector system for dust removal, and the clean flue gas after dust removal treatment is discharged to a chimney through a draught fan; most of the desulfurized ash collected in the ash bucket returns to the bottom of the desulfurization absorption tower system through the material circulating system, is mixed with the flue gas subjected to denitration treatment to continue desulfurization treatment, and a small part of desulfurized ash is transferred to a desulfurized ash storehouse through an ash conveying pipeline by a desulfurized ash discharge system; wherein the dust concentration of the desulfurized flue gas obtained in the step (1) is 890mg/Nm 3 The dust concentration in the clean flue gas after dust removal treatment is 3mg/Nm 3 (ii) a In the dust removing process, the low pressure pulse adopted by the bag-type dust remover systemThe pressure of the compressed air used in the ash flushing and cleaning mode is 0.09Mpa; the conveying pressure (initial end) of a pneumatic conveying bin pump of the desulfurized fly ash discharging system is 0.5MPa, and the ash/gas ratio is 37kg/Nm 3 (ii) a The flow of the fluidization fan of the ash bucket of the dust remover in the material circulating system is 45Nm 3 Permin, full pressure 58.9kPa. The flow rate of the air chute fluidizing fan is 5342Nm 3 The total pressure is 11689kPa for min.
Example 2
The power plant flue gas desulfurization and dust removal process in the embodiment comprises the following steps:
(1) The flue gas of the power plant enters a desulfurization absorption tower system from the bottom after being subjected to denitration treatment by an SNCR/SCR mixed process, is fully mixed with a desulfurizing agent and process water and undergoes desulfurization reaction, and in the process, the desulfurizing agent adopts slaked lime, the water content of the desulfurizing agent is 0.7 percent, and the specific surface area of the desulfurizing agent is 19m 2 (ii)/g; the pressure drop of the desulfurization absorption tower system is 1760Pa, and the calcium-sulfur ratio is 1.5mol/mol; the residence time of the desulfurizing agent is 146s; in addition, the inlet temperature of the flue gas is controlled to be 172 ℃, the outlet temperature is controlled to be 112 ℃, and the flow speed is controlled to be 5m/s; the desulfurization efficiency in the process reaches 96 percent; after the flue gas after denitration treatment is treated by a desulfurization absorption tower system, the desulfurization flue gas is discharged from a flue outlet of the desulfurization absorption tower system; the temperature of the flue gas in a desulfurization absorption tower system in the desulfurization treatment process is 152 ℃, and the flue gas treatment capacity is 910000Nm 3 /h，
(2) The desulfurized flue gas enters a bag-type dust collector system for dust removal, and the clean flue gas after dust removal treatment is discharged to a chimney through a draught fan; most of the desulfurized ash collected in the ash bucket returns to the bottom of the desulfurization absorption tower system through the material circulating system, is mixed with the flue gas subjected to denitration treatment and is subjected to desulfurization treatment continuously, and a small part of desulfurized ash is transferred to a desulfurized ash storehouse through an ash conveying pipeline by a desulfurized ash discharging system; wherein the dust concentration of the desulfurized flue gas obtained in the step (1) is 990mg/Nm 3 The dust concentration in the clean flue gas after dust removal treatment is 2mg/Nm 3 (ii) a In the dust removal process, the pressure intensity of compressed air used in a low-pressure pulse dust removal mode adopted by the bag-type dust remover system is 0.09Mpa; the conveying pressure (initial end) of a pneumatic conveying bin pump of the desulfurized fly ash discharging system is 0.4MPa, and the ash/gas ratio is 29kg/Nm 3 (ii) a Dust remover in material circulating systemThe flow rate of the ash bucket fluidization fan is 49Nm 3 Min, total pressure 57.3kPa. The flow of the air chute fluidization fan is 5820Nm 3 Min, total pressure 11678kPa.
In conclusion, the power plant flue gas desulfurization and dust removal system and the process have the advantages of good desulfurization and dust removal effects, strong stability, high reliability and high desulfurizer utilization rate of the whole system, can reduce environmental pollution and well meet the requirements of flue gas desulfurization and dust removal; the following effects are also provided: in the desulfurization process, industrial water is atomized by a reflux nozzle and then sprayed into an absorption tower, and is mixed with flue gas in the absorption tower at a high mass transfer rate to play a role in activating reaction ions, and meanwhile, the temperature in the tower is reduced, the reaction is promoted to be carried out, and the desulfurization efficiency is not lower than 85%; in the dust removal process, an uninterrupted rotary mortgage pulse ash removal mode is adopted, the number of pulse valves is reduced, and the maintenance workload is reduced; the stable material circulation is established through the material circulation system, and the consumption of the desulfurizer is reduced, so that the requirement of power plant flue gas desulfurization is met.
It should be understood by those skilled in the art that the above embodiments are only for illustrating the present invention and are not to be used as a limitation of the present invention, and that the changes and modifications of the above embodiments are within the scope of the appended claims as long as they are within the true spirit of the present invention.
Claims (10)
1. A power plant flue gas desulfurization and dust removal system is characterized by comprising a desulfurization absorption tower system, a bag-type dust remover system, a desulfurization ash discharge system, a material circulating system, a process water system and a desulfurizer preparation and supply system;
the bottom of the desulfurization absorption tower system is provided with a flue inlet, and the top of the desulfurization absorption tower system is provided with a flue outlet; the desulfurization absorption tower system comprises an inlet section, a tower bottom ash discharge device, a Venturi acceleration section, a circulating fluidized bed reaction section and a top circulating outlet section from bottom to top in sequence;
the air inlet of the bag-type dust collector system is connected with the flue outlet of the desulfurization absorption tower system;
the desulfurization ash discharging system is connected with the bag-type dust remover system;
one end of the material circulating system is connected with an ash bucket of the bag-type dust collector system, and the other end of the material circulating system is connected with the desulfurization absorption tower system;
the backflow type nozzle of the process water system is arranged at the inlet section of the desulfurization absorption tower system;
and the feeding chute of the desulfurizer preparation supply system is connected with the desulfurization absorption tower system.
2. The power plant flue gas desulfurization and dust removal system of claim 1, wherein the flue inlet and the flue outlet are each provided with a temperature and pressure measurement system.
3. The power plant flue gas desulfurization and dust removal system according to claim 1, wherein the bag-type dust collector system comprises an inlet smoke box, a flue gas chamber connected with the inlet smoke box, a gas purification chamber connected with the flue gas chamber, an outlet smoke box connected with the gas purification chamber, a low-pressure pulse ash removal device arranged above the gas purification chamber, an ash hopper arranged below the gas purification chamber, an outlet smoke box connected with the gas purification chamber and an electric control device;
and a filtering cloth bag is arranged in the air purifying chamber, and is prepared from a PPS filtering material subjected to PTFE (polytetrafluoroethylene) impregnation surface treatment.
4. The power plant flue gas desulfurization and dust removal system according to claim 1, wherein the desulfurization ash discharge system comprises an aeration tank and a pneumatic conveying bin pump connected with the aeration tank; the inflation box is connected with an ash bucket of the bag-type dust collector system, and a pneumatic flow shutoff valve is arranged between the inflation box and the pneumatic conveying bin pump;
the pneumatic conveying bin pump adopts a down-leading bin pump, and a feed valve and a discharge valve of the pneumatic conveying bin pump adopt bimetallic gate valves; an automatic blockage clearing device is arranged in the pneumatic conveying bin pump; and the pneumatic conveying bin pump is connected to the desulfurization ash bin through a conveying pipeline.
5. The power plant flue gas desulfurization and dust removal system of claim 1, wherein the material circulation system comprises an ash hopper fluidization fan, an air chute fluidization fan arranged on the air chute, a fluidization fan heater connected with the ash hopper fluidization fan and the air chute fluidization fan, and the pneumatic flow control valve arranged on the air chute;
the ash bucket fluidization fan is arranged at an ash outlet of an ash bucket of the bag-type dust collector system;
one end of the air chute is connected with the ash bucket fluidization fan, and the other end of the air chute is connected with an inlet section of the desulfurization absorption tower system.
6. The power plant flue gas desulfurization and dust removal system according to claim 1, wherein the process water system comprises a process water tank, a high-pressure water pump connected with the process water tank, an atomizing spray gun connected with the high-pressure water pump, and an adjusting device for adjusting the water spraying amount of the atomizing spray gun;
the backflow nozzle is arranged on the atomizing spray gun; the gun body of the atomizing spray gun is made of stainless steel, and the backflow type nozzle is made of tungsten carbide.
7. The power plant flue gas desulfurization and dust removal system of claim 1, wherein the desulfurizer preparation and supply system comprises a quicklime powder tanker, a quicklime bin connected with the quicklime powder tanker, a slaked lime bin connected with the quicklime bin, a slaked lime feeding device arranged at the bottom of the slaked lime bin, and a feeding chute connected with the slaked lime feeding device;
the feeding chute is arranged at the inlet section of the desulfurization absorption tower system.
8. The power plant flue gas desulfurization and dust removal process is characterized by being treated by the power plant flue gas desulfurization and dust removal system as set forth in any one of claims 1-7, and comprising the following steps:
(1) The flue gas after denitration treatment enters a desulfurization absorption tower system for desulfurization treatment, and after the flue gas is mixed with process water and a desulfurizing agent for desulfurization, the desulfurized flue gas is discharged from a flue outlet of the desulfurization absorption tower system;
(2) And after the desulfurization flue gas is dedusted by the bag-type dust remover system, a part of desulfurization ash is discharged by the desulfurization ash discharge system, and the rest part of desulfurization ash returns to the bottom of the desulfurization absorption tower system through the material circulating system to continue desulfurization reaction.
9. The power plant flue gas desulfurization and dust removal process according to claim 8, wherein in the step (1), the denitration treatment adopts an SNCR/SCR mixed process; and/or
In the desulfurization treatment process, the treatment capacity of the flue gas is 670000-940000 Nm 3 The temperature of the flue gas is 80-162 ℃; and/or
The pressure drop of the desulfurization absorption tower system is 300-2200 Pa, and the calcium-sulfur ratio is 1.2-1.6 mol/mol; and/or
The desulfurizer adopts slaked lime, the water content is lower than 1.5 percent, and the specific surface area is more than 15m 2 (iv) g; and/or
The residence time of the desulfurizer is 6 to 158s; and/or
The inlet temperature of the flue gas is 158-172 ℃, the outlet temperature is 82-112 ℃, and the flow rate is 5-7 m/s; and/or
The desulfurization efficiency of the desulfurization treatment is 85-96%.
10. The power plant flue gas desulfurization and dust removal process according to claim 8, wherein in the step (2), before the dust removal treatment, the dust concentration of the desulfurized flue gas is 620-1100 mg/Nm 3 The dust concentration in the clean flue gas after dust removal treatment is less than 5mg/Nm 3 。
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