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CN-122006444-A - Double-circulation desulfurization process for strengthening removal of condensable particles based on condensation effect

CN122006444ACN 122006444 ACN122006444 ACN 122006444ACN-122006444-A

Abstract

The invention belongs to the field of environmental protection and energy utilization, and particularly relates to a double-circulation desulfurization process for strengthening removal of condensable particles based on condensation effect. Firstly, the technology utilizes a heat exchanger to realize the cooling and heat exchange of Ca (OH) 2 slurry with stronger activity and alkalinity added with a scale inhibitor, and the cooled upper circulation spraying slurry can promote condensation growth and removal of particulate matters and condensable particulate matters such as SO 3 while strengthening desulfurization exothermic reaction and corrosion resistance about SO 2 absorption. And secondly, cooling and heat exchanging the desulfurization flue gas by utilizing a condensation pipeline additionally arranged under the mechanical demister, and strengthening and removing the large-particle-size particles by the demister by promoting condensation and growth of the particles and the condensable particles such as SO 3 and the like in the cooled desulfurization flue gas. And finally, the cold medium in the heat exchanger and the condensing pipeline is circulated by a circulating pump, absorbs heat of the desulfurization slurry and the flue gas, is used for carrying out waste heat recovery and utilization on primary air or boiler water supply and the like, reduces heat loss of the coal-fired power plant, and improves the energy utilization rate.

Inventors

  • ZHOU ZHIYONG
  • LV JIANYI
  • ZHANG YUPENG

Assignees

  • 华北电力大学（保定）

Dates

Publication Date
20260512
Application Date
20260413

Claims (5)

  1. 1. A double-circulation desulfurization process for strengthening removal of condensable particles based on condensation effect is characterized by comprising a lower circulation desulfurization tower main body (1), an upper circulation desulfurization outer tower (2), an oxidation fan (3), a gypsum discharge pump (4) and the like, wherein coal-fired flue gas enters the lower circulation desulfurization tower main body (1) through a flue inlet (11) of the desulfurization tower, the flue gas upwards flows through a lower circulation spray layer, an upper circulation spray layer and a demister in sequence, slurries in the lower circulation desulfurization tower main body (1) and the upper circulation desulfurization outer tower (2) are pumped into air by the oxidation fan (3) for forced oxidation, gypsum generated after oxidation is discharged by the gypsum discharge pump (4), caCO 3 slurry (12) in the lower circulation desulfurization tower main body (1) is pumped into a mechanical atomization nozzle (14) through a lower circulation slurry pump (13), the spray slurry is in reverse contact with the flue gas, ca (OH) 2 slurry (21) in the upper circulation desulfurization outer tower (2) is pumped into the mechanical atomization nozzle (23) through an upper circulation slurry pump (22) for forced oxidation, gypsum generated after oxidation is discharged by the gypsum discharge pump (4), caCO 3 slurry (12) in the lower circulation desulfurization outer tower main body (2) is pumped into a mechanical atomization nozzle (14) through a heat exchanger (25), and returns to an evaporator (25) of an evaporator (25), the demisting device consists of a lower condensation pipeline (31) and an upper mechanical demister (32), wherein the cold medium (air or water and the like) in the condensation pipeline (31) is provided by the cold medium circulation pump (28) and realizes heat exchange and cooling of desulfurized flue gas.
  2. 2. The double-circulation desulfurization process for strengthening the removal of condensable particulates based on a condensation effect according to claim 1, wherein a dividing wall type heat exchanger (26) outside a slurry conveying pipe (25) and an immersed coil heat exchanger (27) in an upper circulation outer tower are additionally arranged on the upper circulation basis, a cold medium (such as air or water) in the heat exchanger is circulated through a cold medium circulating pump (28) and realizes the cooling and heat exchange of Ca (OH) 2 slurry (21), and the cooled upper circulation spraying slurry can strengthen desulfurization exothermic reaction about SO 2 absorption on one hand and promote the condensation growth and removal of the particulates and the condensable particulates such as SO 3 on the other hand.
  3. 3. The double-circulation desulfurization process for strengthening the removal of condensable particulates based on a condensation effect according to claim 1, wherein a layer of condensation pipeline (31) is additionally arranged between an upper circulation mechanical atomizing nozzle (23) and a mechanical demister (32), a cold medium (air or water and the like) which is used for completing circulation by a cold medium circulation pump (28) is introduced into the condensation pipeline (31), cooling and heat exchange of desulfurization flue gas are realized, and strengthening removal of large-particle-size particulates by the demister is realized by promoting condensation growth of the particulates and the condensable particulates such as SO 3 in the cooled desulfurization flue gas.
  4. 4. The double-circulation desulfurization process for strengthening the removal of condensable particulates based on the condensation effect according to claim 1 and 2 is characterized in that Ca (OH) 2 slurry (21) with stronger alkalinity, activity and solubility of a scale inhibitor added in an upper circulation desulfurization outer tower (2) is pumped into a mechanical atomization nozzle (23) through an upper circulation slurry pump (22) to form a spray layer so as to realize strengthening of desulfurization effect, scaling prevention, reduction of equipment corrosion speed and prolonging of equipment service life, slurry collected in a liquid collecting hopper (24) returns to the upper circulation desulfurization outer tower (2) through a conveying pipe (25), and Ca (OH) 2 can be obtained by CaO calcined by CaCO 3 , so that the addition and the mixing in the production process of a coal-fired power plant are facilitated, the optimization of the production flow of the thermal power plant is facilitated, and the production efficiency is improved.
  5. 5. The double-circulation desulfurization process for enhancing removal of condensable particulates based on condensation effects according to claim 1, 2, 3 and 4, wherein a dividing wall type heat exchanger (26), an immersed coil heat exchanger (27) and cold media (such as air or water) in a condensation pipeline (31) are added on the basis of double circulation, circulation is completed by a circulating pump (28), cooling and heat exchange of desulfurization slurry and flue gas are realized, and the cold media such as air or water after heat absorption can be used for waste heat utilization of primary air or boiler water and the like, so that heat loss of a coal-fired power plant is reduced, and energy utilization rate is improved.

Description

Double-circulation desulfurization process for strengthening removal of condensable particles based on condensation effect Technical Field The invention belongs to the field of environmental protection and energy utilization, and in particular relates to a double-circulation desulfurization process for realizing desulfurization slurry and flue gas cooling by utilizing a heat exchanger and a condensation pipeline to enhance condensation effect and strengthen condensable particulate matters removal and simultaneously realizing desulfurization effect improvement and waste heat recovery utilization. Background Under the guidance of the national important strategic demands of coal and electricity energy conservation and emission reduction, blue sky guard war, deep pollution control and fast combat and the like, the emission control result of routine pollutants such as SO 2, particulate matters and the like is remarkable in recent years, but the emission of unconventional pollutants such as condensable particulate matters is increased year by year, and the emission of the condensable particulate matters is generally more than 50 percent, even more than 80 percent of the total particulate matters, SO the harm is not negligible. At present, research on condensable particles in coal-fired flue gas at home and abroad mainly aims at testing means, removal effect, component detection, characteristic analysis and the like, and the removal of the condensable particles is enhanced by regulating and controlling the temperature, humidity and flow rate of the flue gas, slurry concentration, spraying amount and other operation conditions. However, from the basis of existing equipment or devices, the cooperative enhanced removal of condensable particles in flue gas of a desulfurizing tower is only recently reported by utilizing and optimizing the existing process or structure. The single-tower double-circulation desulfurization technology is an efficient flue gas desulfurization technology developed on the basis of the traditional single-tower single circulation, a slurry system is divided into two independent circulation loops to respectively bear different functions by arranging a conical liquid collecting hopper in an absorption tower, the efficiency, the economy, the adaptability and the reliability of the slurry system are all superior to those of the traditional single-circulation technology, the key advantages are that independent optimization control is realized through functional partition, the pH of slurry in a lower circulation area is low and focuses on efficient oxidation of calcium sulfite and gypsum crystallization, the quality of byproducts is improved, the pH of the upper circulation area is high and focuses on efficient absorption of residual SO 2, and deep desulfurization is realized under a lower liquid-gas ratio. For the removal of condensable particles, condensation and other means are used for promoting the growth and removal of the condensable particles, so that the method is a feasible way. Therefore, the invention provides a double-circulation desulfurization process for strengthening the removal of condensable particles based on a condensation effect on the basis of a single-tower double-circulation desulfurization technology by combining an effective means of condensation, and the condensation growth and removal of the condensable particles such as SO 3 and the like are finally promoted by comprehensively considering physical reaction and chemical reaction through lowering the temperature of slurry and flue gas while increasing the pH of the slurry in an upper circulation zone of the double-circulation desulfurization process, and the recovery and the utilization of waste heat of a coal-fired power plant are realized. Disclosure of Invention The invention provides a double-circulation desulfurization process for strengthening the removal of condensable particles based on a condensation effect, which is characterized in that a heat exchanger and a condensation pipeline are additionally arranged on the basis of a single-tower double-circulation desulfurization technology to realize the cooling of slurry and flue gas, and the removal of the condensable particles in the desulfurization flue gas is strengthened through the condensation effect, and meanwhile, the recovery and the utilization of waste heat of a coal-fired power plant are realized. The invention mainly comprises the following contents: The double-circulation desulfurization process for strengthening the removal of condensable particles based on condensation effect comprises a lower circulation desulfurization tower main body, an upper circulation desulfurization outer tower, an oxidation fan, a gypsum discharge pump and the like, wherein coal-fired flue gas enters the lower circulation desulfurization tower main body through a flue inlet of the desulfurization tower, the flue gas upwards flows through a lower circulation spray layer, an upp