CN217220819U

CN217220819U - Denitration system after wet desulfurization

Info

Publication number: CN217220819U
Application number: CN202220724192.0U
Authority: CN
Inventors: 张佩; 李小溪; 白子琦; 卢宝新; 张勇超
Original assignee: SHENYANG YUANDA ENVIRONMENTAL ENGINEERING CO LTD
Current assignee: SHENYANG YUANDA ENVIRONMENTAL ENGINEERING CO LTD
Priority date: 2022-03-31
Filing date: 2022-03-31
Publication date: 2022-08-19
Anticipated expiration: 2032-03-31

Abstract

The utility model relates to a denitration system after wet flue gas desulfurization, including SCR reactor, reductant injection apparatus, flue gas heat exchanger's shell side export and reductant injection apparatus inlet pipeline intercommunication, flue gas heat exchanger's tube side entry and SCR reactor outlet pipeline intercommunication, its technical essential is: the shell side inlet of the flue gas heat exchanger is communicated with the shell side outlet of the flue gas condenser, the shell side inlet of the flue gas condenser is communicated with an outlet pipeline of the wet desulphurization device, a cooling circulating water pump, a cooling water tank and a cooling tower are sequentially connected between the tube side inlet and the tube side outlet of the flue gas condenser, a branch pipeline is additionally arranged on the outlet pipeline of the SCR reactor, the tail end of the branch pipeline is connected with a mixing fan, and the tail end of the outlet pipeline of the mixing fan is communicated with the shell side outlet pipeline of the flue gas condenser. The system solves the problems that the desulfurization flue gas corrodes the follow-up denitration equipment and blocks the denitration catalyst, greatly reduces the influence on the denitration equipment, and has low energy consumption.

Description

Denitration system after wet desulfurization

Technical Field

The utility model belongs to the technical field of the atmosphere pollution control, concretely relates to denitration system behind wet flue gas desulfurization.

Background

Environmental protection is a basic national policy in China, and people have higher and higher call for environmental protection along with the continuous improvement of environmental protection laws and regulations and the acceleration of technical progress of various industries in China. The continuous development of the industry makes China face more and more environmental pressure, and SO2 and NOx are one of the main causes of environmental pollution. Therefore, controlling the production of SO2 and NOx and reducing the emission of SO2 and NOx have become important responsibilities facing the industry.

Currently, desulfurization can be classified into wet, dry and semi-dry processes according to the wet and dry state. The flue gas wet desulphurization technology has high desulphurization efficiency, and the development of the denitration technology combined with the wet desulphurization has wide industrial application prospect based on the current situation that the wet flue gas desulphurization technology in China is widely applied. However, the flue gas subjected to the wet flue gas desulfurization process is saturated flue gas, fog drops can be generated in the flue gas, and the fog drops can absorb residual sulfur in the flue gas to generate sulfurous acid or sulfuric acid, so that the subsequent denitration equipment is corroded; and the salt in the flue gas can also enter subsequent denitration equipment along with the fog drops, so that the risk of catalyst blockage exists.

Disclosure of Invention

The utility model aims at providing a structural configuration is reasonable, use safe and reliable's denitration system behind wet flue gas desulfurization, solves the desulfurization flue gas and causes the problem of corroding and blockking up the denitration catalyst to follow-up denitration device, reduces the influence to denitration device greatly, and energy consumption is little simultaneously.

The technical scheme of the utility model is that:

the utility model provides a deNOx systems after wet flue gas desulfurization, includes the SCR reactor, locates reductant injection apparatus on the SCR reactor inlet pipeline, locates the gas heater on reductant injection apparatus inlet pipeline, gas heater's shell side export and reductant injection apparatus inlet pipeline intercommunication, gas heater's tube side entry and SCR reactor outlet pipeline intercommunication, reductant injection apparatus inlet pipeline outside is equipped with the heating furnace, and its technical essential is: the shell side inlet of the flue gas heat exchanger is communicated with the shell side outlet of the flue gas condenser, the shell side inlet of the flue gas condenser is communicated with an outlet pipeline of the wet desulphurization device, a cooling circulating water pump, a cooling water tank and a cooling tower are sequentially connected between the tube side inlet and the tube side outlet of the flue gas condenser, a branch pipeline is additionally arranged on the outlet pipeline of the SCR reactor, the tail end of the branch pipeline is connected with a mixing fan, and the tail end of the outlet pipeline of the mixing fan is communicated with the shell side outlet pipeline of the flue gas condenser.

Foretell denitration system after wet flue gas desulfurization, flue gas condenser includes the casing, locates the cooling tube bank in the casing, locates the collection liquid chamber of casing bottom, the cooling tube bank comprises the vertical pipeline section that the multistage is parallel, connects the changeover portion between two sections adjacent vertical pipeline sections, and the cooling tube bank forms a plurality of flue gases at the interval along flue gas flow direction in the casing and blocks the cross-section, and the casing bottom surface is the fretwork face to the fog drip condensate of flue gas passes through the fretwork face and reachs collection liquid chamber, the bottom surface in collection liquid chamber is equipped with the leakage fluid dram.

In the wet desulfurization and denitrification system, each section of the longitudinal pipe section is uniformly provided with the plurality of cooling fins from top to bottom, the cooling fins are obliquely arranged, the roots of the cooling fins are arranged below, and the free ends of the cooling fins are arranged above.

Foretell denitration system behind wet flue gas desulfurization, gas heater's tube side exit linkage draught fan, the outlet pipe end and the chimney lower part of draught fan are advanced the smoke mouth and are connected, be equipped with heat exchanger tube bank among the gas heater, heat exchanger tube bank's surface forms the interception face that corresponds the flue gas flow direction, it contains salt particulate matter loading end after for the heat transfer to block the cross-section, gas heater is equipped with the soot blower towards heat exchanger tube bank.

In the denitration system after wet desulphurization, the number of the mixing fans is two, the mixing fans are connected in parallel, the tail ends of the branch pipelines are respectively connected with the inlets of the two mixing fans, the tail ends of the outlet pipelines of the two mixing fans are intersected at one position and communicated with the shell pass outlet pipeline of the flue gas condenser, and one main fan and one spare fan are respectively used.

In the wet desulfurization and denitration system, the number of the cooling circulating water pumps is two and the two cooling circulating water pumps are connected in parallel, the tube pass inlet pipeline of the flue gas condenser is connected with the outlets of the two cooling circulating water pumps, the tail ends of the inlet pipelines of the two cooling circulating water pumps are intersected at one position and communicated with the cooling water tank, and the two cooling circulating water pumps are used mainly and separately.

In the denitration system after wet desulphurization, the reducing agent injection device comprises the injection cavity communicated with the flue gas heat exchanger and the multilayer injection spray head assembly arranged in the injection cavity, so that the reducing agent is uniformly injected to the flue gas.

The utility model has the advantages that:

1. flue gas passing through the desulfurization wet-type electrostatic precipitator is firstly condensed through a flue gas condenser, and in the condensing process, due to the fact that the temperature is reduced, precipitated fog drops are in contact with sulfur in the flue gas, the specific surface area is increased, the precipitated fog drops absorb the sulfur in the flue gas, most of the sulfur, dust and fog drops are collected together in a liquid collecting cavity to be taken out of a system, and corrosion to equipment in a follow-up denitration system is reduced.

2. And the cooled flue gas is pressurized and heated up continuously through the mixing air, and is heated up again through the flue gas heat exchanger, and finally the flue gas is further heated up to the temperature of the denitration reaction by adopting a heating mode of a heating furnace. In the process, before sending high-temperature clean flue gas to the flue gas heat exchanger through the mixing fan, the flue gas becomes unsaturated flue gas after being heated by 3-5 degrees, salt-containing dissolved substances carried in the flue gas are dehydrated, crystallized and separated out, and the separated particulate matters are deposited on the surface of a heat exchange tube bundle in the flue gas heat exchanger, so that periodic blowing can be adopted, the amount of entering a denitration catalyst is greatly reduced, and the risk of blocking the catalyst is reduced.

3. In order to save fuel, the flue gas heat exchanger and the mixing fan are arranged, the waste heat of the denitration clean flue gas of the SCR reactor is fully utilized, the load requirement of the heating furnace is reduced, and the operating cost of the denitration system is greatly reduced.

To sum up, the utility model discloses utilize flue gas condensation and flue gas to mix the wind pressurization and heat up, reduce water and salt in the flue gas after former wet flue gas desulfurization to alleviate the corruption to follow-up deNOx systems equipment, avoid blockking up the denitration catalyst, the temperature gradient in the rational utilization system sets up the heat exchanger system, reduces energy resource consumption.

Drawings

FIG. 1 is a schematic view of the present invention;

FIG. 2 is a schematic diagram of the flue gas condenser;

figure 3 is a cross-sectional view of a flue gas condenser.

In the figure: 1. the system comprises a flue gas condenser, 101 a shell, 102 cooling pipe bundles, 103 cooling fins, 104 a liquid collecting cavity, 105 hollow surfaces, 106 liquid discharging ports, 2 a flue gas heat exchanger, 3 a heating furnace, 4 a reducing agent injection device, 5 an SCR reactor, 6 a blending fan, 7 an induced draft fan, 8 a chimney, 9 a cooling circulating water pump, 10 a cooling water tank and 11 a cooling tower.

Detailed Description

As shown in fig. 1 to fig. 3, the denitration system after wet desulfurization includes an SCR reactor 5, a reducing agent injection device 4 disposed on an inlet pipeline of the SCR reactor 5, and a flue gas heat exchanger 2 disposed on an inlet pipeline of the reducing agent injection device 4. The shell side outlet of the flue gas heat exchanger 2 is communicated with an inlet pipeline of a reducing agent injection device 4, the tube side inlet of the flue gas heat exchanger 2 is communicated with an outlet pipeline of the SCR reactor 5, and a heating furnace 3 is arranged outside the inlet pipeline of the reducing agent injection device 4.

The shell-side inlet of the flue gas heat exchanger 2 is communicated with the shell-side outlet of the flue gas condenser 1, the shell-side inlet of the flue gas condenser 1 is communicated with an outlet pipeline of the wet desulphurization device, a cooling circulating water pump 9, a cooling water tank 10 and a cooling tower 11 are sequentially connected between the tube-side inlet and the tube-side outlet of the flue gas condenser 1, a branch pipeline is additionally arranged on an outlet pipeline of the SCR reactor 5, the tail end of the branch pipeline is connected with a blending fan 6, and the tail end of the outlet pipeline of the blending fan 6 is communicated with the shell-side outlet pipeline of the flue gas condenser 1.

In this embodiment, the flue gas condenser 1 includes a shell 101, a cooling tube bundle 102 disposed in the shell 101, and a liquid collection chamber 104 disposed at the bottom of the shell, where the cooling tube bundle 102 is composed of a plurality of parallel longitudinal tube segments and a transition segment connected between two adjacent longitudinal tube segments. The cooling tube bundle 102 forms a plurality of smoke blocking sections at intervals in the shell 101 along the flow direction of smoke, the bottom surface of the shell 101 is a hollow surface 105, so that fog and droplet condensate of the smoke can reach the liquid collecting cavity 104 through the hollow surface 105, and the bottom surface of the liquid collecting cavity 104 is provided with a liquid outlet 106. Every section longitudinal pipe section from top to bottom evenly is equipped with a plurality of cooling fin 103, cooling fin 103 slant is arranged, and the root is under, and the free end is last. The utility model discloses a flue gas heat exchanger 2, including flue

gas heat exchanger

2, 8 chimney lower parts of chimney inlet are connected to the tube side exit linkage draught fan 7 of flue gas heat exchanger 2, the outlet pipeline end of draught fan 7 is connected with the chimney lower part, be equipped with heat exchanger tube bank among the flue gas heat exchanger 2, heat exchanger tube bank's surface forms the interception face that corresponds the flue gas flow direction, it contains salt class particulate matter loading end for the heat transfer back to block the cross-section, flue gas heat exchanger 2 is equipped with the soot blower towards heat exchanger tube bank, omits in the figure.

The number of the mixing fans 6 is two and the mixing fans are connected in parallel, the tail ends of the branch pipelines are respectively connected with the inlets of the two mixing fans 6, the tail ends of the outlet pipelines of the two mixing fans 6 are intersected at one position and communicated with the shell pass outlet pipeline of the flue gas condenser 1, and one mixing fan is used for one device and the other mixing fan is used for another device. The quantity of cooling circulation water pump 9 is two and parallelly connected, the tube side entry pipeline of flue gas condenser 1 and the exit linkage of two cooling circulation water pumps 9, and the entry pipeline end intersection of two cooling circulation water pumps 9 is in one and with cooling water pool 10 intercommunication, and a main use is equipped with respectively the use. The reducing agent injection device 4 comprises an injection cavity communicated with the flue gas heat exchanger 2 and a multilayer injection spray head assembly arranged in the injection cavity, so as to uniformly inject the reducing agent into the flue gas.

The working principle is as follows:

the temperature of the desulfurized flue gas is reduced by 3-5 ℃ through the flue gas condenser 1, liquid drops and particles in the flue gas are intercepted by the cooling tube bundle 102, so that the flue gas is subjected to violent turbulence and impact, the liquid particles wrap the solid particles and grow gradually, the solid particles are adhered to the cooling tube bundle and finally form a water film with enough thickness, the water film flows from top to bottom, the adhered solid particles are discharged downwards into the liquid collecting cavity 104 at the bottom, and the amount of sulfur and dust entering subsequent equipment is greatly reduced. After the condensed flue gas is heated up successively through the mixing fan 6 and the flue gas heat exchanger 2, salt-containing solute fog drops carried in the flue gas can be dehydrated, crystallized and separated out, the separated out particulate matters are deposited on the surface of the heat exchange tube bundle, and the blowing of the soot blower is adopted, so that the amount of entering the SCR catalyst is greatly reduced, and the risk of blocking the catalyst is reduced. The heating of flue gas adopts the form of mixing heat, and the clean flue gas of high temperature that comes out from SCR reactor 5 is in advance to advance gas heater 2, draws forth a part of clean flue gas of high temperature through mixing fan 6 and adds in the saturated flue gas behind the desulfurization gas heater 2 before, becomes unsaturated flue gas after heating this flue gas 3-5 degrees and reentries gas heater 2 and realizes the intensification. The utility model discloses a mode that the condensation adds intensification can effectively avoid wet flue gas desulfurization to follow-up SCR system's influence.

The embodiments of the present invention have been described in detail, but the description is only for the preferred embodiments of the present invention and should not be construed as limiting the scope of the present invention. All equivalent changes and modifications made within the scope of the present invention should be covered by the present patent.

Claims

1. The utility model provides a denitration system after wet flue gas desulfurization, includes the SCR reactor, locates reductant injection apparatus on SCR reactor inlet pipeline, locates the flue gas heat exchanger on reductant injection apparatus inlet pipeline, the shell side export and the reductant injection apparatus inlet pipeline intercommunication of flue gas heat exchanger, flue gas heat exchanger's tube side entry and SCR reactor outlet pipeline intercommunication, reductant injection apparatus inlet pipeline outside is equipped with heating furnace, its characterized in that: the shell side inlet of the flue gas heat exchanger is communicated with the shell side outlet of the flue gas condenser, the shell side inlet of the flue gas condenser is communicated with an outlet pipeline of the wet desulphurization device, a cooling circulating water pump, a cooling water tank and a cooling tower are sequentially connected between the tube side inlet and the tube side outlet of the flue gas condenser, a branch pipeline is additionally arranged on the outlet pipeline of the SCR reactor, the tail end of the branch pipeline is connected with a mixing fan, and the tail end of the outlet pipeline of the mixing fan is communicated with the shell side outlet pipeline of the flue gas condenser.

2. The denitration system after wet desulfurization of claim 1, which is characterized in that: the flue gas condenser includes the casing, locates cooling tube bank in the casing, locates the collection liquid chamber of casing bottom, cooling tube bank comprises the vertical pipe section that the multistage is parallel, connects the changeover portion between two sections adjacent vertical pipe sections, and cooling tube bank forms a plurality of flue gases at the interval along flue gas flow direction in the casing and blocks the cross-section, and the casing bottom surface is the fretwork face to the fog drip condensate of flue gas passes through the fretwork face and reachs collection liquid chamber, the bottom surface in collection liquid chamber is equipped with the leakage fluid dram.

3. The system of claim 2, wherein the denitration system after wet desulfurization comprises: every section vertical tube section from top to bottom evenly is equipped with a plurality of cooling fin, cooling fin slant is arranged, and the root is under, and the free end is last.

4. The system of claim 1, wherein the denitration system after wet desulfurization comprises: the utility model discloses a flue gas heat exchanger, including flue gas heat exchanger, chimney, heat exchanger, smoke inlet, heat exchanger, smoke outlet, draught fan, the outlet pipe end and the chimney lower part of draught fan are connected, be equipped with heat exchanger tube bank among the flue gas heat exchanger, heat exchanger tube bank's surface forms the interception face that corresponds the flue gas flow direction, it contains salt class particulate matter loading end for the heat transfer back to block the cross-section, flue gas heat exchanger is equipped with the soot blower towards heat exchanger tube bank.

5. The system of claim 1, wherein the denitration system after wet desulfurization comprises: the mixing fans are connected in parallel, the tail ends of the branch pipelines are respectively connected with inlets of the two mixing fans, the tail ends of outlet pipelines of the two mixing fans are intersected at one position and communicated with a shell side outlet pipeline of the flue gas condenser, and a main fan and a spare fan are used respectively.

6. The system of claim 1, wherein the denitration system after wet desulfurization comprises: the quantity of cooling circulating water pump is two and parallelly connected, flue gas condenser's tube side entry pipeline and two cooling circulating water pump exit linkage, two cooling circulating water pump's entry pipeline end meet in a department and with cooling water pool intercommunication, main one is equipped with and uses respectively.

7. The system of claim 1, wherein the denitration system after wet desulfurization comprises: the reducing agent injection device comprises an injection cavity communicated with the flue gas heat exchanger and a multilayer injection spray head assembly arranged in the injection cavity.