CN213746834U

CN213746834U - Unpowered multichannel flue gas heating device

Info

Publication number: CN213746834U
Application number: CN202022828520.5U
Authority: CN
Inventors: 吴景兴; 张安文; 吕中琪
Original assignee: Xian Thermal Power Research Institute Co Ltd
Current assignee: Xian Thermal Power Research Institute Co Ltd
Priority date: 2020-11-30
Filing date: 2020-11-30
Publication date: 2021-07-20
Anticipated expiration: 2030-11-30

Abstract

The utility model provides an unpowered multichannel flue gas heating device, which comprises a furnace smoke outlet and an insertion opening, wherein the furnace smoke outlet is arranged at the side wrapping wall on a horizontal flue and is arranged at the downstream of a high-temperature superheater; the insertion opening is formed in the front end of the horizontal flue of the SCR reactor; the smoke outlet and the insertion opening of the furnace are connected through a connecting pipe; the utility model discloses can throw at any time according to load needs adjusting valve and use, close under the high load, do not leak when closing, do not block when opening, can improve SCR entry smoke temperature 50 ℃ after the device drops into, hot primary air temperature 30 ℃. The method has remarkable effects of meeting the requirements of deep peak regulation and drying capacity of the pulverizing system at the medium and low load stages of the large thermal power generating unit and improving the combustion efficiency of the boiler.

Description

Unpowered multichannel flue gas heating device

Technical Field

The utility model belongs to the equipment field of thermal power plant, concretely relates to unpowered multichannel flue gas heating device.

Background

At present, the structure and the layout of a power supply are optimized, the cleaning substitution of a supply side is accelerated, and clean energy such as wind and light is vigorously developed; strictly controlling the total amount of coal and electricity, optimizing the layout of the coal and electricity, and converting the coal and electricity into positioning; promote coal electricity flexibility transformation energetically for flexible power construction such as pumped storage and novel energy storage technology application.

The ratio of the coal electric installation machine to the generated energy is continuously reduced. The percentage of the coal electric installation in the whole country is reduced from 59% to 50.7%, the percentage of the generated energy is reduced from 67.9% to 61.5%, the percentage of the generated energy is reduced by 8.3% and 6.4%, the net increase of the coal electric installation is 1.87 hundred million kilowatts, the utilization hours of the coal electric power are 4170-4446 hours, and the number of the electricity generation in 2019 is 4366 hours. With the large-scale development and technical progress of wind power and solar power generation, the power generation cost is remarkably reduced, the power generation of petrochemical energy is replaced to become a dominant power supply, and the economy of the power generation system far exceeds that of the petrochemical energy.

Therefore, the petrochemical energy power generation needs to be modified in operation flexibility, the peak regulation capacity is excavated, the current and future new energy consumption dilemma is broken, and wind and light abandonment is reduced.

The number of hours of use of the thermal power generating unit is continuously reduced, the operation under low load becomes a normal state, and the operation of the thermal power generating unit under low load time accounts for about 40-50% of the total operation time. The inlet smoke temperature of the SCR system is low under low load, the catalyst is difficult to meet the temperature requirement, and even is forced to exit, and the environmental protection index does not reach the standard.

When the existing coal burner unit is provided with 50% ECR, the smoke temperature at the inlet of an SCR reactor is only about 290 ℃, the NOx emission value exceeds the standard, and meanwhile, the drying capacity of a powder making system is reduced due to low temperature of hot primary air under low load, the load capacity of the unit is reduced, and the plant power rate is increased.

According to statistics of a Chinese thermal power generation network, by 2020, the number of thermal power generating units in China is about 3000, 1000MW ultra-supercritical units are put into production for 140, 30-ten thousand kilowatt-level and 60-thousand kilowatt-level coal-fired units are about 2500, and the units need to operate a flexible transformation technology to different degrees. How to solve the problems that the low-load denitration inlet smoke temperature is lower, the drying capacity of a pulverizing system is seriously insufficient, the coal consumption is increased, and the deep peak regulation of a unit is a focus of close attention of a power generation enterprise and needs to be solved urgently. Therefore, the technology has wide market prospect.

Disclosure of Invention

An object of the utility model is to provide an unpowered multichannel flue gas heating device for the low-load denitration entry flue gas temperature that solves the existence of current coal-fired unit is on the low side, the defect that powder process system drying capacity is not enough, the coal consumption increases.

In order to achieve the above purpose, the utility model adopts the following technical scheme:

the utility model provides an unpowered multichannel flue gas heating device, which comprises a furnace smoke outlet and an insertion opening, wherein the furnace smoke outlet is arranged at the side wrapping wall on a horizontal flue and is arranged at the downstream of a high-temperature superheater; the insertion opening is formed in the front end of the horizontal flue of the SCR reactor; the smoke outlet and the insertion opening of the furnace are connected through a connecting pipe.

Preferably, a plurality of smoke outlets of the furnace are arranged and symmetrically arranged along the wrapping walls on two sides of the horizontal flue.

Preferably, the smoke outlets of the smoke exhaust ventilator arranged on the same side are staggered up and down.

Preferably, the insertion openings are provided with a plurality of insertion openings which are uniformly distributed at the front end of the horizontal flue of the SCR reactor, and the distance between two adjacent insertion openings 2 is 2-5 m.

Preferably, the connecting pipe is of a circular pipe structure.

Preferably, the connecting pipe is provided with a shutoff door and an adjusting door, wherein the shutoff door is arranged on one side of the smoke hole of the furnace; the adjusting door is arranged on one side of the insertion opening.

Preferably, an inclination angle is arranged between the axis of the connecting pipe and the axis of the insertion opening, and the inclination angle is 30-50 degrees.

Preferably, the depth of the connecting pipe inserted into the insertion opening is 200-400 mm.

The utility model has the advantages that:

the utility model provides an unpowered multichannel flue gas heating device, mainly utilize the pressure differential, the difference in temperature that form between the upstream and downstream heated surface of boiler when operation, the trompil is located at the side wrapper behind the boiler horizontal flue high temperature superheater, directly extract the flue gas of this department and introduce the front end of the horizontal flue of SCR reactor of economizer export through a plurality of pipelines under well low load, directly heat cigarette and hot primary air in the SCR reactor; the problems of low-load denitration inlet smoke temperature, insufficient drying capacity of a pulverizing system and increased coal consumption of the existing coal-fired unit are solved.

Furthermore, in order to overcome the difficult problems of large space and uneasy mixing of the flue gas of the SCR reactor (generally between 12m and 20 m), the utility model provides a flue gas heating technology with a plurality of circular pipelines and multi-point mixing.

Further, the extraction point is arranged at the position where the smoke temperature is 500-600 ℃ and the negative pressure is 150-200 Pa; the insertion point is selected at the position with the smoke temperature of more than 250 ℃ and the negative pressure of 600 Pa-800 Pa, so that sufficient pressure difference and temperature difference between the extraction point and the insertion point can be ensured; and then the flue gas can be extracted in an unpowered way to directly heat the flue gas temperature and the hot primary air temperature in the SCR reactor.

Furthermore, the round pipe is used as the connecting pipe, so that the defect that the square pipe is easy to block and causes smoke leakage because a louver door is needed is overcome.

To sum up, the utility model discloses can throw in at any time according to load needs adjusting valve, close under the high load, do not leak when closing, do not block when opening, can improve SCR entry smoke temperature 50 ℃, hot wind temperature 30 ℃ after the device drops into. The method has remarkable effects of meeting the requirements of deep peak regulation and drying capacity of the pulverizing system at the medium and low load stages of the large thermal power generating unit and improving the combustion efficiency of the boiler.

Drawings

FIG. 1 is a schematic plan view of an unpowered multi-channel flue gas heating device;

FIG. 2 is a schematic side view of an unpowered multi-channel flue gas heating device;

FIG. 3 is a schematic view of the orientation of a single-sided duct of the unpowered multi-channel flue gas heating device;

fig. 4 is a schematic drawing of the extraction point opening.

Detailed Description

The present invention will be described in further detail with reference to the accompanying drawings.

As shown in fig. 1 and fig. 2, the unpowered multi-channel flue gas heating device provided by the present invention comprises a furnace smoke outlet 1 and an insertion opening 2, wherein the furnace smoke outlet 1 is arranged at a side wrapping wall on a horizontal flue and is arranged at the downstream of a high temperature superheater; the insertion opening 2 is formed at the highest position of the SCR reactor; the smoke outlet 1 and the insertion opening 2 of the furnace are connected through a connecting pipe 3.

The temperature of the smoke outlet 1 of the furnace is 500-600 ℃, and the negative pressure is 150-200 Pa.

The smoke temperature of the insertion point is more than or equal to 250 ℃, and the negative pressure is 600 Pa-800 Pa.

The connecting pipe is of a circular pipe structure, and the diameter of the connecting pipe is 1.4-1.6 m.

4-8 smoke outlets are formed in the furnace-drawing smoke hole 1, the wrapping walls on the left side and the right side are symmetrically distributed along the horizontal flue, and the furnace-drawing smoke holes on the wrapping walls on the single side are arranged in a staggered mode (see figure 2), so that later-stage pipeline arrangement is facilitated.

The inserting openings are provided with the same number as the smoke outlets of the furnace and are uniformly distributed at the front end of the horizontal flue of the SCR reactor (namely, the front end inclined plane or the vicinity of the inclined plane of the horizontal flue of the SCR reactor).

The spacing between two adjacent insertion openings 2 is 2-5 m.

An inclination angle is arranged between the axis of the connecting pipe 3 and the axis of the insertion opening, and the inclination angle is 30-50 degrees.

The depth of the connecting pipe 3 inserted into the insertion opening is 200-400mm

A shutoff door 4 and an adjusting door 5 are arranged on the connecting pipeline 3, wherein the shutoff door 4 is arranged on one side of the furnace smoke outlet 1; the regulating door 5 is arranged on one side of the insertion opening 2.

The distance between the furnace smoke outlet 1 and the high-temperature superheater is 400-600 mm.

The utility model provides a pair of unpowered multichannel flue gas heating method, including following step:

the preset amount of flue gas is extracted in a powerless mode by utilizing the pressure difference formed between upstream equipment and downstream equipment, and the flue gas is conveyed to the SCR reactor to heat the flue gas.

Example 1

The test unit is a 350MW unit boiler of a Fuxin power plant, the width of a flue of an SCR reactor is 12m, and 4 circular pipelines and 4-point mixing technology are used. Preferably about 500mm behind the high-temperature superheater of the horizontal flue. The interval between adjacent mixing points is about 2.4m, and the material is 12cr1 MoV. The insertion point is arranged at the front end of a horizontal flue of the SCR reactor, the insertion point is also the highest position of a flue gas space of the SCR reactor, and the pipeline is sealed after being inserted by about 250mm at an insertion depth of 45 degrees because no heating surface is arranged at the insertion point. And 2 door controls of a shut-off door and an adjusting door are arranged, and heat-resistant materials are selected. The extraction point is selected after the horizontal flue high-temperature superheater, the extraction point smoke temperature is 500-600 ℃, and the negative pressure is 150-200 Pa. The insertion point is at the highest position of the SCR reactor, the negative pressure at the position is high, sufficient pressure difference can be guaranteed, and the flue gas flow direction is changed from vertical to horizontal to be easy to mix.

The receiving base low-grade calorific value of the brown coal for combustion is 13200kJ/kg, the proportion of the extracted medium-temperature flue gas to the total flue gas is about 15%, and the resistance of a system for extracting the medium-temperature flue gas is calculated to be 337.23 Pa. If the smoke negative pressure near the SCR inlet (the medium temperature smoke system inlet) can reach more than-340 Pa in the actual operation, the requirement of smoke extraction can be met, and the mixed smoke temperature is controlled to be more than 310 ℃.

The smoke extraction calculation results are shown in table 1. The results of the resistance calculations are shown in table 2.

TABLE 1 calculation of boiler fume extraction

TABLE 2 calculation of resistance for a smoking gas system

Effects of use

The unpowered multi-channel flue gas heating device is applied to a 350MW unit boiler of a Fuxin power plant for the first time, the air door has good tightness, the adjusting mode is simple and reliable, the device is standby under high load, and the system is put into use at any time under low load.

Compared with the medium-temperature flue gas system before operation, the maximum rising amplitude of the flue gas temperature at the inlet of the SCR system is about 50 ℃, the rising amplitude of the primary air temperature and the secondary air temperature is about 30 ℃, the flue gas temperature at the outlet of the preheater is about 5-8 ℃, the combustion efficiency of the boiler is improved by more than 6 percent, and the output of a single coal mill can be improved by about 6 t/h. The effect is obvious after the design optimization.

Claims

1. The unpowered multi-channel flue gas heating device is characterized by comprising a furnace smoke outlet (1) and an insertion opening (2), wherein the furnace smoke outlet (1) is formed in a side wrapping wall on a horizontal flue and is arranged at the downstream of a high-temperature superheater; the insertion opening (2) is formed in the front end of a horizontal flue of the SCR reactor; the furnace smoke outlet (1) is connected with the insertion opening (2) through a connecting pipe (3).

2. The unpowered multichannel flue gas heating device according to claim 1, wherein the furnace smoke outlet (1) is provided with a plurality of smoke outlets symmetrically arranged along the wrapping wall on two sides of the horizontal flue.

3. The unpowered multi-channel flue gas heating device according to claim 2, wherein the furnace smoke outlets on the same side are staggered.

4. An unpowered multichannel flue gas heating device according to claim 1, characterized in that the insertion openings (2) are provided in plurality, evenly distributed at the front end of the horizontal flue of the SCR reactor, and the distance between two adjacent insertion openings (2) is 2-5 m.

5. The unpowered multichannel flue gas heating device according to claim 1, wherein the connecting pipe (3) is of a round pipe structure.

6. The unpowered multichannel flue gas heating device according to claim 1, wherein the connecting pipe (3) is provided with a shutoff gate (4) and an adjusting gate (5), wherein the shutoff gate (4) is arranged on one side of the furnace smoke outlet (1); the adjusting door (5) is arranged on one side of the insertion opening (2).

7. An unpowered multichannel flue gas heating device according to claim 1, characterized in that an inclination angle is provided between the axis of the connecting pipe (3) and the axis of the insertion opening (2), the inclination angle being 30 ° -50 °.

8. The unpowered multichannel flue gas heating device according to claim 1, wherein the depth of the connecting pipe (3) inserted into the insertion opening (2) is 200-400 mm.