CN116045341A - Operation method of recovering flue gas waste heat for inter-seasonal buried pipe heat storage and heat supply - Google Patents

Abstract

An operation method for recovering flue gas waste heat for cross-seasonal buried pipe heat storage and heat supply. The special heat storage system includes boilers, flue gas-water heat exchangers, valves, water pumps, ground source heat pump units, and buried pipe storage Heat body and heat user, the flue gas-water heat exchanger is placed in the boiler furnace, the ground source heat pump unit is connected with the flue gas-water heat exchanger and the buried pipe heat storage body, the ground source heat pump unit The heat supply side pipeline is connected to the pipeline from the flue gas waste heat to the heat user, and the flue gas-water heat exchanger is connected to the heat storage body of the buried pipe; during the non-heating period, the waste heat of the flue gas is sent to the heat storage body of the buried pipe; heating In the early stage, when the outlet water temperature of the heat storage body of the buried pipe is higher than 40°C, the flue gas-water heat exchanger and the heat storage soil directly supply heat; the outlet water temperature of the heat storage body of the buried pipe is lower than 40°C, and the flue gas-water heat exchanger and ground source heat pump units. The invention is suitable for conventional coal-fired units, improves the thermal efficiency of the coal-fired units, and improves the heat supply income of the coal-fired units.

Description

Operation method of recovering flue gas waste heat for inter-seasonal buried pipe heat storage and heat supply

technical field

The invention relates to a technology for utilizing waste heat of flue gas of a coal-fired power station boiler, in particular to an operation method for heat supply using stored and recovered waste heat of flue gas.

Background technique

The efficiency of coal-fired boilers is 90% to 94%, but the waste heat of flue gas accounts for about 4% to 8% of fuel heat, and the heat loss of exhaust gas mainly comes from the heat loss of boiler units. At present, the waste heat of boiler flue gas of coal-fired units cannot be effectively utilized, and the heat supply of coal-fired power plants has the problem of imbalance between waste heat resources and heating demand time. If the waste heat of the flue gas can be recovered and utilized in depth, the thermal efficiency of the boiler will be further improved, the fuel consumption will be reduced, and energy will be saved, which has important research value.

Contents of the invention

In order to solve the problem that the waste heat of the flue gas of the coal-fired unit boiler can not be effectively utilized, and the heat supply of the existing coal-fired power plant has an imbalance between the waste heat resource and the heating demand time, the present invention proposes a method for recovering the waste heat of the flue gas for cross-seasonal buried pipes The operation method of heat storage and heat supply, which can store the waste heat of flue gas in the non-heating period to the heating period for effective use, effectively meet the heat demand of heat users in the heating period, and reduce the carbon emission of coal-fired units under the same heating area , improving thermal efficiency.

In order to achieve the purpose of the above invention, the present invention proposes an operation method for recovering flue gas waste heat for cross-seasonal buried pipe heat storage and heat supply, which is characterized in that: the special heat storage system includes a boiler, a flue gas-water heat exchanger, Valves, water pumps, ground source heat pump units, buried pipe heat storage bodies, heat users, including:

The flue gas-water heat exchanger is placed in the boiler furnace, the ground source heat pump unit is connected with the flue gas-water heat exchanger and the buried pipe heat storage body through pipelines, and the heat supply side of the ground source heat pump unit The pipeline is connected to the pipeline from the waste heat of the flue gas to the heat user, and the flue gas-water heat exchanger is connected to the heat storage body of the buried pipe through the pipeline.

Heat storage and heat supply operation control method: In the non-heating period, the waste heat of the flue gas is recovered and sent to the heat storage body of the buried pipe. With the increase of the waste heat recovery of the flue gas, the soil around the heat storage body of the buried pipe passes through Heat exchange and temperature rise, use the soil to store the waste heat of the flue gas; in the heating period, use the waste heat of the flue gas and the heat storage of the soil to provide heat to the user; If the temperature is higher than 40°C, use a flue gas-water heat exchanger and heat storage soil to directly supply heat; if the outlet water temperature of the local buried heat storage body is lower than 40°C, use a flue gas-water heat exchanger and a ground source heat pump The operation mode in which the unit supplies heat to the user.

Further, the water pumps are respectively arranged in the pipeline connecting the flue gas-water heat exchanger and the buried pipe heat storage body, and the ground source heat pump unit is connected to the heat user In the pipeline and in the pipeline connecting the ground source heat pump unit and the buried pipe heat storage body.

Further, all pipelines are provided with valves.

Compared with conventional technology, the beneficial effects of the present invention are:

(1) The present invention uses three types of heat sources: buried pipe heat storage body, ground source heat pump unit, and flue gas waste heat to supply heat to heat users. Through temperature control, the two heat supply modes of the buried pipe heat storage unit combined with the waste heat of the flue gas to supply heat to the heat user, and the ground source heat pump unit combined with the waste heat of the flue gas to supply heat to the heat user are switched to ensure the heating temperature requirements of the user end. While making full use of the residual heat of the flue gas, the thermal user comfort is ensured.

(2) The present invention adopts the operation mode of recovering low-grade flue gas waste heat for heating during the non-heating period. This mode solves the problem of the time mismatch between the waste heat resources of the flue gas and the needs of heat users, and realizes non-heating The effective utilization of the waste heat of flue gas in the early stage increases the heat supply of coal-fired units.

(3) The invention only adds a flue gas-water heat exchanger to absorb the waste heat of the flue gas in the transformation of the coal-fired unit, basically does not change the original structure of the boiler, and reduces the cost of transformation, research and development and design.

Description of drawings

Fig. 1 is a schematic diagram of an operation mode of recovering flue gas waste heat for cross-seasonal buried pipe heat storage and heat supply in the present invention.

In the figure, 1-boiler furnace; 2-flue gas-water heat exchanger, 3-first water pump; 4-first valve; 5-second valve; 6-third valve; 7-fourth valve; 8- 2nd water pump; 9-ground source heat pump unit; 10-third water pump; 11-fifth valve; 12-buried pipe heat storage body; 13-heat user; 14-first pipeline; 15-second pipeline ; 16-the third pipeline; 17-the fourth pipeline; 18-the fifth pipeline.

Detailed ways

Referring to Figure 1, a system for recovering waste heat from flue gas for cross-season buried pipe heat storage mainly includes: boiler furnace 1, flue gas-water heat exchanger 2, first water pump 3, first valve 4, and second valve 5 , the third valve 6, the fourth valve 7, the second water pump 8, the ground source heat pump unit 9, the third water pump 10, the fifth valve 11, the buried pipe heat storage body 12, the heat user 13, the first pipeline 14, The second pipeline 15, the third pipeline 16, the fourth pipeline 17, the fifth pipeline 18, wherein:

The first water pump 3 and the first valve 4 are connected with the flue gas-water heat exchanger 2 and the buried pipe heat storage body 12 through the fourth pipeline 17 .

The second valve 5 and the third valve 6 are connected with the flue gas-water heat exchanger 2 and the first pipeline 14 through the fourth pipeline 17 and the fifth pipeline 18 .

The fourth valve 7 and the second water pump 8 are connected with the ground source heat pump unit 9 and the heat user 13 through the first pipeline 14 .

The first valve 4 , the second valve 5 , and the third valve 6 are connected with the buried pipe heat storage body 12 and the heat user 13 through the fourth pipeline 17 .

Heat storage and heat supply operation method:

In the non-heating period heat storage condition, open the first valve 4, close the second valve 5, the third valve 6, the fourth valve 7, and the fifth valve 11, and transfer the heat from the flue gas-water heat exchanger 2 to Buried pipe heat storage body storage.

In the heat release condition during the heating period, when the soil temperature of the heat storage body of the buried pipe is higher than 40°C, the first valve 4, the second valve 5, and the third valve 6 are opened, and the fifth valve 11 is closed, and the flue gas from - The heat of the water heat exchanger 2 and the heat stored in the buried pipe heat storage body 12 are delivered to the heat user 13 at the same time.

In the heat release condition during the heating period, when the soil temperature of the buried heat storage body is lower than 40°C, the second valve 5, the third valve 6, the fourth valve 7, and the fifth valve 11 are opened, and the first valve 4 is closed. The heat from the flue gas-water heat exchanger 2 and the heat stored in the buried pipe heat storage body 12 are heated up by the ground source heat pump unit 9 and delivered to the heat user 13 at the same time.

Claims (3)

1. An operation method for heat storage and heat supply of cross-season buried pipes by recovering flue gas waste heat is characterized by comprising the following steps of: the special heat storage system comprises a boiler, a flue gas-water heat exchanger, a valve, a water pump, a ground source heat pump unit, a buried pipe heat storage body and a heat user, wherein:

the flue gas-water heat exchanger is arranged in a boiler hearth, the ground source heat pump unit is connected with the flue gas-water heat exchanger and the ground buried pipe heat storage body through pipelines, a pipeline on the heat supply side of the ground source heat pump unit is connected with a pipeline from flue gas waste heat to a heat user, and the flue gas-water heat exchanger is connected with the ground buried pipe heat storage body through a pipeline;

the heat storage and supply operation method comprises the following steps: in the non-heating period, flue gas waste heat recovery is carried out, waste heat is sent into the buried pipe heat storage body, and as the flue gas waste heat recovery amount increases, the temperature of soil around the buried pipe heat storage body is raised through heat exchange, and the flue gas waste heat is stored by utilizing the soil; in the heating period, the waste heat of the flue gas and the heat accumulation of the soil are utilized to supply heat to a user; determining a heating mode of the soil end by adopting a temperature control mode, and adopting a mode of directly heating by adopting a flue gas-water heat exchanger and heat storage soil when the water outlet temperature of a buried pipe heat storage body is higher than 40 ℃; when the water outlet temperature of the ground heat storage body is lower than 40 ℃, the operation mode that the flue gas-water heat exchanger and the ground source heat pump unit supply heat to users is adopted.

2. The method for operating the cross-season buried pipe heat storage and supply by recovering flue gas waste heat according to claim 1, wherein the method comprises the following steps: the water pump in the special heat storage system is respectively arranged in a pipeline connected with the flue gas-water heat exchanger and the buried pipe heat storage body, a pipeline connected with the ground source heat pump unit and the heat user and a pipeline connected with the ground source heat pump unit and the buried pipe heat storage body.

3. The method for operating the cross-season buried pipe heat storage and supply by recovering flue gas waste heat according to claim 1, wherein the method comprises the following steps: valves are arranged in all pipelines of the special heat storage system.

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