WO2021218074A1

WO2021218074A1 - Flue structure for sncr denitrification of flue gas from pulverized coal boiler and heating sludge-drying heat transfer oil

Info

Publication number: WO2021218074A1
Application number: PCT/CN2020/123324
Authority: WO
Inventors: 林伟荣; 李昱喆; 宋润; 王海涛; 时正海; 高洪培; 苏林
Original assignee: 华能国际电力股份有限公司; 中国华能集团清洁能源技术研究院有限公司
Priority date: 2020-04-29
Filing date: 2020-10-23
Publication date: 2021-11-04
Also published as: CN111425874A

Abstract

A flue structure for the SNCR denitration of flue gas from a pulverized coal boiler (1) and heating sludge-drying heat transfer oil. An SNCR denitrification device is provided in a suitable region in a flue (2) of the pulverized coal boiler (1) to allow a flue gas that contains a reducing agent to be fully mixed when flowing through same, so that the ideal denitrification efficiency may be obtained; and a heat conduction oil heater pipe (9) is embedded in a basic mechanism unit to obtain a portion of the heat energy in the high-temperature flue gas for drying urban sludge.

Description

A flue structure used for SNCR denitrification of pulverized coal boiler flue gas and heating sludge drying heat transfer oil

【Technical Field】

The invention relates to the field of environmental protection technology for coal-fired boilers and the harmless treatment of wastes, in particular to a flue structure used for SNCR denitrification of pulverized coal boiler flue gas and heating sludge drying heat transfer oil.

【Background technique】

In order to meet the ultra-low emission requirements for pollutants (such as NO _x, etc.) emitted by coal-fired units, pulverized coal boilers generally use selective catalytic reduction (SCR) to _{remove NO x} , which has high construction costs for denitrification devices , The catalyst consumption is large, the catalyst is invalid or poisoned, the disposal cost of the waste catalyst is high, and the potential harm to the environment is great. If the flue gas can substantially remove most of its NO _x before it enters the SCR device, it can effectively alleviate the denitration pressure of the downstream SCR device, which will help extend the life of the SCR catalyst and produce good economic and social benefits.

At the same time, the use of coal-fired units coupled with combustion to dispose of biomass (such as urban sludge, etc.) is an important method to achieve waste biomass reduction, recycling, and harmlessness; especially, for the utilization of urban sludge The flue gas heats the heat transfer oil to make it dry with the sludge in non-contact heat exchange in the sludge dryer, which is a widely used method of sludge drying. The dried sludge can be used as fuel and burned in the pulverized coal boiler to achieve the purpose of resource utilization.

[Summary of the invention]

The purpose of the present invention is to provide a flue structure for SNCR denitration of pulverized coal boiler flue gas and heat sludge drying heat transfer oil, which solves the problem of high construction cost and high catalyst use cost in the existing pulverized coal boiler flue gas denitration , And the complex structure of the dry urban sludge heat exchanger that exists when the coal-fired unit is coupled to burn and dispose of biomass.

In order to achieve the above objectives, the present invention adopts the following technical solutions to achieve:

The present invention provides a flue structure for denitration of pulverized coal boiler flue gas SNCR and heating sludge drying heat transfer oil, including a basic mechanism unit for flue gas SNCR denitrification device, and the basic mechanism unit is placed in the SCR device The upstream; the basic mechanism unit is provided with multiple, and is arranged in an S-shaped structure in the inner cavity of the flue; a spray gun is provided above the first basic mechanism unit, and the spray gun is connected with the SNCR reducing agent Container; The basic mechanism unit is embedded with a heat-conducting oil heater pipeline, and the inlet of the heat-conducting oil heater pipeline is connected to the sludge drying system.

Preferably, the basic mechanism unit includes a first baffle and a second baffle, wherein the first baffle and the second baffle are respectively arranged on two side walls of the flue and form an S-shaped channel.

Preferably, the first baffle and the second baffle have the same structure; wherein the first baffle is a heat-resistant steel plate structure, and both sides of the heat-resistant steel plate structure are coated with a layer of refractory and wear-resistant material .

Preferably, one side of the first baffle and the second baffle is pre-buried with heat-conducting oil heater pipes, or both sides of the first baffle and the second baffle are pre-buried with heat-conducting oil for heating器管。 The pipeline.

Preferably, the flue is further provided with a first inclined baffle and a second inclined baffle, and an inclination angle is set between the first inclined baffle and the second inclined baffle and the side wall of the flue; wherein, The first inclined baffle is placed upstream of the first basic mechanism unit and connected to the first basic mechanism unit; the second inclined baffle is placed downstream of the last basic mechanism unit and is connected to the last basic mechanism unit connect.

Preferably, the first inclined baffle and the second inclined baffle are arranged on the two side walls of the flue in a mirror image structure; the first inclined baffle and the second inclined baffle have the same structure, wherein the first inclined baffle The baffle is a heat-resistant steel plate-shaped structure, and both sides of the heat-resistant steel plate-shaped structure are coated with refractory and wear-resistant materials.

Preferably, a spray gun is arranged above the first inclined baffle, and the spray gun is connected with an SNCR reducing agent container.

Preferably, heat-conducting oil heater pipes are pre-buried on one side of the first inclined baffle and the second inclined baffle; or both sides of the first inclined baffle and the second inclined baffle are Pre-embedded with heat-conducting oil heater pipeline.

Preferably, the heat-conducting oil heater pipeline is arranged in an S-shaped structure; the inlet of the heat-conducting oil heater pipeline is connected to a heat-conducting oil inlet header; the outlet of the heat-conducting oil heater pipeline is connected to a heat-conducting oil outlet header, so The heat-conducting oil outlet of the heat-conducting oil outlet header is connected to the inlet of the sludge dryer; the outlet of the sludge dryer is connected to the heat-conducting oil inlet header.

Compared with the prior art, the present invention has the following beneficial effects:

The present invention provides a flue structure used for SNCR denitrification of pulverized coal boiler flue gas and heating sludge drying heat transfer oil. An SNCR denitrification device is arranged in a suitable area in the flue of the pulverized coal boiler to make the flue gas entrapped with reducing agent It can achieve full mixing when flowing through it, and obtain the ideal denitration efficiency; embed the heat-conducting oil heater pipeline in the basic mechanism unit, simplify the heat-conducting oil heating system, and obtain part of the heat energy in the high-temperature flue gas to dry the city Sludge; the entire design structure is simple, while greatly reducing the NO _x concentration of the flue gas before the SCR device, the energy in the flue gas is obtained with a simple structure to dry the municipal sludge, which is used in the reduction of pollutants and the utilization of municipal waste. Both aspects can reap better economic and social benefits.

Further, the first inclined baffle is arranged so that the flue forms a tapered flue; the second inclined baffle is arranged to form a divergent flue gas flow channel to reduce the flow pressure loss.

【Explanation of the drawings】

In order to explain the technical solutions of the embodiments of the present invention more clearly, the following will briefly introduce the drawings needed in the embodiments. It should be understood that the following drawings only show some embodiments of the present invention, and therefore do not It should be regarded as a limitation of the scope. For those of ordinary skill in the art, other related drawings can be obtained based on these drawings without creative work.

Figure 1 is a front view of the flue structure involved in the present invention;

Figure 2 is a top view of the flue structure involved in the present invention;

Figure 3 is a structural diagram of the baffle;

Figure 4 is a schematic diagram of the size of a high-efficiency SNCR denitrification device for pulverized coal boiler flue gas;

Figure 5 is a diagram of a sludge drying system that uses flue gas to heat heat transfer oil.

【Detailed ways】

The present invention will be further described in detail below in conjunction with the accompanying drawings.

As shown in Figures 1 to 5, the present invention provides a flue structure for SNCR denitrification of pulverized coal boiler flue gas and heating sludge drying heat transfer oil, including pulverized coal boiler 1, flue 2, first inclined Baffle 3, first baffle 4, second baffle 5, second inclined baffle 6, fire-resistant and wear-resistant material 7, heat-resistant steel plate structure 8, heat-conducting oil heater pipe 9, control valve 10, heat-conducting oil The inlet header 11, the heat transfer oil outlet header 12, the circulating pump 13, the sludge dryer 14, the SCR device 15 and the spray gun 16, wherein the flue gas outlet of the pulverized coal boiler 1 is connected with a flue 2, and the flue The flue gas outlet of 2 is connected to the flue gas inlet of the SCR device 15.

In the inner cavity of the flue 2, a first inclined baffle 3, a plurality of basic mechanism units for a flue gas high-efficiency SNCR denitrification device, and a second inclined baffle 6 are sequentially arranged from upstream to downstream. The baffle 3 is connected to the first basic mechanism unit; the second inclined baffle 6 is connected to the last basic mechanism unit.

The first inclined baffle 3 and the second inclined baffle 6 are arranged in a mirror image structure.

The first inclined baffle 3 and the second inclined baffle 6 have the same structure, wherein the first inclined baffle 3 includes a heat-resistant steel plate structure 8, and both sides of the heat-resistant steel plate structure 8 are coated There are refractory and wear-resistant materials7.

The basic mechanism unit includes a first baffle 4 and a second baffle 5, wherein the first baffle 4 and the second baffle 5 form an S-shaped channel.

The first inclined baffle 3 and the first baffle 4 are connected; the second inclined baffle 6 and the second baffle 5 are connected.

The first baffle 4 and the second baffle 5 have the same structure, wherein the heights of the first baffle 4 and the second baffle are the same; the first baffle 4 includes a heat-resistant steel plate-shaped structure 8. Both sides of the steel plate structure 8 are coated with a refractory and wear-resistant material layer 7.

The spacing between two adjacent baffles is equal.

A plurality of spray guns 16 are arranged above the first inclined baffle 3 or the first baffle 4.

The spray gun 16 is connected with an SNCR reducing agent container.

One side of the first inclined baffle 3, the first baffle 4, the second baffle 5 or the second inclined baffle 6 is pre-buried with a heat-conducting oil heater pipe 9 with an S-shaped structure, and the heat-conducting oil is heated The inlet of the heat-conducting oil heater pipe 9 is connected to the heat-conducting oil inlet header 11; the outlet of the heat-conducting oil heater pipe 9 is connected to the heat-conducting oil outlet header 12, and the heat-conducting oil outlet of the heat-conducting oil outlet header 12 is connected to the sewage through the circulating pump 13 The entrance of the mud dryer 14.

The outlet of the sludge dryer is connected to the heat transfer oil inlet header 11 through the control valve 10.

The working engineering of the present invention:

A first inclined baffle 3 with a certain angle α is arranged at an appropriate position of the flue 2 of the pulverized coal boiler 1 to form a tapered flue. The middle part of the first inclined baffle 3 is a heat-resistant steel plate structure 8, two The side is coated with a certain thickness of refractory and wear-resistant material 7.

Connected to the first inclined baffle 3 is the first baffle 4, and the first baffle 4 and the second baffle 5 arranged in relative positions constitute the basic mechanism unit of the flue gas high-efficiency SNCR denitrification device.

The first baffle 4 and the second baffle 5 are respectively arranged on both sides of the

flue

2, and 1 to 3 basic structural units can be arranged in the flue 2 according to requirements and space conditions.

A second inclined baffle 6 with a certain angle is connected to the tail of the flue gas SNCR denitrification device to form a divergent flue gas flow channel to reduce the flow pressure loss.

In terms of specific size design, the first baffle 4 and the second baffle 5 of the basic mechanism unit of SNCR denitrification have the same height H2, and the distances H1 and H3 between the baffle and the wall of the flue 2 remain the same. The distances D1 and D2 are also kept the same, and the cross-sectional area of the flow area remains unchanged, which can effectively reduce the pressure loss of flue gas flow.

The number and size of the basic structure (H1, H2 and D1 and the angle α of the inclined baffle) used by the SNCR denitrification device can be specifically designed in accordance with the actual size of the flue and the detailed information of the boiler operating parameters.

In order to promote the good mixing of the SNCR reducing agent and the flue gas, a certain number of spray guns 16 are arranged in an appropriate area on the upper part of the first inclined baffle 3 or the first baffle 4 close to the wall surface of the flue 2.

The SNCR reducing agent (such as urea solution, ammonia water, etc.) is atomized by the spray gun 16 and sprayed into the high-speed flowing flue gas, and the evaporation is completed in a short time.

The high-speed flue gas entrains the reducing agent and enters the SNCR denitrification device. Due to the diversion effect of the first baffle 4 and the second baffle 5, the flue gas will flow along a U-shaped or inverted U-shaped path in the SNCR denitrification device. It promotes the mixing of flue gas and reducing agent, and at the same time, high-speed flow will form a strong backflow zone in the first baffle 4 and second baffle 5 perpendicular to the wall surface of the flue 2, further improving the local area of the reducing agent and The degree of mixing of the flue gas.

The flue gas and the reducing agent flow through 1 to 3 basic mechanism units in the SNCR denitrification device to achieve effective mixing, thereby obtaining a relatively ideal SNCR denitrification efficiency (such as more than 65%), and greatly reducing the NO _x in the flue gas. The concentration relieves the denitration pressure of the downstream SCR device 15.

In order to prolong the life of the first baffle 4 and the second baffle 5, a heat-resistant steel plate structure 8 (such as 310S stainless steel) can be selected as the baffle material, and at the same time, a certain thickness of refractory and wear-resistant material layer is covered on both sides 7.

The thickness of the heat-resistant steel plate structure 8 and the thickness of the fire-resistant and wear-resistant material layer 7 can be integrated with the conditions of the pulverized coal boiler 1 and the SNCR denitrification device.

Since the first inclined baffle 3, the second inclined baffle 6 or the first baffle 4, and the second baffle 5 in the flue 2 are located at a relatively high temperature, they can be used as a heat source for the heat transfer oil for heating the sludge. .

The heat-conducting oil heater pipe 9 is pre-buried in the refractory and wear-resistant material layer 7 of the first inclined baffle 3, the second inclined baffle 6 or the first baffle 4 and the second baffle 5 in a serpentine manner. The windward side of the relevant baffle is arranged separately, or both sides can be arranged at the same time.

The specific shape and buried position of the heat-conducting oil heater pipe 9 need to be specifically designed in accordance with the requirements of the sludge to be dried. Arrange the heat-conducting oil heater pipe 9 in the refractory and wear-resistant material layer 7 and realize effective heating, that is, it avoids the complicated structural change that requires a separate heat exchanger in the downstream flue, simplifies the sludge drying system, and makes full use of The design structure of the SNCR denitration device involved in this patent.

The heat-conducting oil is heated in the heat-conducting oil heater pipeline 9 and collected to the heat-conducting oil outlet header 12, driven by the circulating pump 13, the high-temperature heat-conducting oil enters the sludge dryer 14, and it is cooled and flows while drying the sludge. The control valve 10 enters the heat-conducting oil inlet header 11, and is finally distributed to each heat-conducting oil heater pipe 9 to realize circulating heating.

The invention uses a simple structure baffle to construct a high-efficiency SNCR denitration device in a suitable area in the flue 2 of the pulverized coal boiler 1, so that the flue gas entrained with the reducing agent can be fully mixed when flowing through it, and ideal denitrification efficiency can be obtained.

At the same time, a heat-conducting oil heater pipe 9 is arranged in the refractory and wear-resistant material layer 7 of the baffle to simplify the heat-conducting oil heating system and obtain part of the heat energy in the high-temperature flue gas to dry the municipal sludge. The entire design has a simple structure. While greatly reducing the NO _x concentration of the flue gas in front of the SCR device 15, the energy in the flue gas is obtained with a simple structure to dry the urban sludge, which is in terms of pollutant emission reduction and urban waste utilization. Both can reap better economic and social benefits.

The above content is only to illustrate the technical ideas of the present invention, and cannot be used to limit the scope of protection of the present invention. Any changes made on the basis of the technical solutions based on the technical ideas proposed by the present invention fall into the claims of the present invention. Within the scope of protection.

Claims

A flue structure used for SNCR denitration of pulverized coal boiler flue gas and heating sludge drying heat transfer oil, which is characterized in that it includes a basic mechanism unit for flue gas SNCR denitration, and the basic mechanism unit is placed in the SCR device ( 15) upstream; the basic mechanism unit is provided with multiple, and is arranged in an S-shaped structure in the inner cavity of the flue (2); or the first basic mechanism unit is provided with a spray gun (16) above , The spray gun (16) is connected with an SNCR reductant container; the basic mechanism unit is embedded with a heat-conducting oil heater pipe (9), and the inlet of the heat-conducting oil heater pipe (9) is connected to a sludge drying system .
A flue structure for SNCR denitrification of pulverized coal boiler flue gas and heat sludge drying heat transfer oil according to claim 1, wherein the basic mechanism unit includes a first baffle (4) and a first baffle (4). Two baffles (5), wherein the first baffle (4) and the second baffle (5) are respectively arranged on the two side walls of the flue (2) and form an S-shaped channel.
The flue structure for SNCR denitrification of pulverized coal boiler flue gas and heat sludge drying heat transfer oil according to claim 2, wherein the first baffle (4) and the second baffle ( The structure of 5) is the same; wherein, the first baffle (4) is a heat-resistant steel plate structure, and both sides of the heat-resistant steel plate structure are coated with a refractory and wear-resistant material layer.
The flue structure for SNCR denitrification of pulverized coal boiler flue gas and heat sludge drying heat transfer oil according to claim 2, wherein the first baffle (4) and the second baffle ( 5) One side of the heat-conducting oil heater pipe (9) is pre-buried, or the first baffle (4) and the second baffle (5) are pre-buried with heat-conducting oil heater pipes ( 9).
A flue structure for SNCR denitrification of pulverized coal boiler flue gas and heat sludge drying heat transfer oil according to claim 1, wherein the flue (2) is also provided with a first inclined baffle The plate (3) and the second inclined baffle (6) are provided with an inclination angle between the first inclined baffle (3) and the second inclined baffle (6) and the side wall of the flue (2); wherein , The first inclined baffle (3) is placed upstream of the first basic mechanism unit and connected to the first basic mechanism unit; the second inclined baffle (6) is placed downstream of the last basic mechanism unit, And connect with the last basic mechanism unit.
A flue structure for SNCR denitrification of pulverized coal boiler flue gas and heat sludge drying heat transfer oil according to claim 5, characterized in that the first inclined baffle (3) and the second inclined baffle The plates (6) are arranged on the two side walls of the flue (2) in a mirror image structure; the first inclined baffle (3) and the second inclined baffle (6) have the same structure, wherein the first inclined baffle ( 3) It is a heat-resistant steel plate-shaped structure, and both sides of the heat-resistant steel plate-shaped structure (8) are coated with refractory and wear-resistant materials.
A flue structure for SNCR denitrification of pulverized coal boiler flue gas and heat sludge drying heat transfer oil according to claim 5, wherein a spray gun is provided above the first inclined baffle (3) (16) The spray gun (16) is connected with an SNCR reducing agent container.
A flue structure for SNCR denitrification of pulverized coal boiler flue gas and heat sludge drying heat transfer oil according to claim 5, characterized in that the first inclined baffle (3) and the second inclined baffle A heat-conducting oil heater pipe (9) is pre-buried on one side of the plate (6); or both sides of the first inclined baffle (3) and the second inclined baffle (6) are pre-buried Heat transfer oil heater pipe (9).
A flue structure for SNCR denitrification of pulverized coal boiler flue gas and heat sludge drying heat transfer oil according to claim 5, wherein the heat transfer oil heater pipe (9) is arranged in an S-shaped structure The inlet of the heat-conducting oil heater pipe (9) is connected to a heat-conducting oil inlet header (11); the outlet of the heat-conducting oil heater pipe (9) is connected to a heat-conducting oil outlet header (12), the heat-conducting oil The heat-conducting oil outlet of the outlet header (12) is connected to the inlet of the sludge dryer (14); the outlet of the sludge dryer is connected to the heat-conducting oil inlet header (11).