CN209763246U - A flue gas waste heat utilization heating system - Google Patents

Abstract

The utility model provides a flue gas waste heat utilization heating system, which includes a flue gas side heat exchanger and a hot water side heat exchanger, and the flue gas side heat exchanger is connected with a flue gas side hot water inlet pipe passing through a heating medium, The cold water outlet pipe on the flue gas side, the unit condensate water inlet pipe and the unit condensate return water pipe passing through the heated medium; among them, the hot water inlet pipe on the flue gas side connected to the hot water outlet pipe of the gas-water heat exchanger is simultaneously Connect the hot water measuring hot water inlet pipe of the hot water side heat exchanger through the water inlet pipe of the hot water side heat exchanger, and the hot water side cold water outlet pipe of the hot water side heat exchanger pass through the return pipe of the hot water side heat exchanger Connect the cold water outlet pipe on the flue gas side; the heating medium passes through the inlet pipe of the heat exchanger on the hot water side and the return pipe of the heat exchanger on the hot water side; the system of the utility model can use the waste heat of the flue gas for heating of the unit during the heating period Heat supply increases the heating capacity of the unit, effectively reduces the coal consumption of the unit for power generation, and improves the energy utilization rate.

Description

A flue gas waste heat utilization heating system

technical field

The utility model relates to the field of heat supply systems of thermal power plants, in particular to a heat supply system utilizing waste heat of flue gas, and is a novel steam turbine heat supply system.

Background technique

Constrained by environmental pressure, central heating is the trend of urban development in the future, and thermal power unit heating transformation is the main technical means to improve heating capacity. At present, thermal power units mainly adopt the technology of extracting steam for heating, which requires high parameters such as steam source temperature and pressure. However, as the heat load increases year by year, the heating capacity of many units has reached the upper limit, and it is urgent to consider new technologies to increase the heating capacity of the units.

Existing steam sources for heating steam turbines are mostly exhaust steam from medium-pressure cylinders as heating steam, or exhaust steam from steam turbines is used for heating by means of high back pressure and light shaft.

Most of the existing flue gas waste heat utilization systems use the gas-water heat exchanger to absorb the waste heat from the boiler exhaust and send it to the condensate pipeline to recover heat, reducing the coal consumption of the unit for power generation.

Utility model content

In order to increase the heating capacity of the unit and effectively reduce the coal consumption of the unit, the utility model provides a flue gas waste heat utilization series heating system, which can use the waste heat of the flue gas to increase the heating capacity and power generation of the unit during the heating period, and improve the utilization rate of waste heat.

The utility model adopts the following technical solutions:

A flue gas waste heat utilization heating system, including a flue gas side heat exchanger and a hot water side heat exchanger, the flue gas side heat exchanger is connected to the flue gas side hot water inlet pipe passing through the heating medium, the flue gas side cold water Outlet pipes, unit condensate inlet pipes and unit condensate return pipes passing through the heated medium;

Among them, the hot water inlet pipe on the flue gas side connected to the hot water outlet pipe of the air-water heat exchanger is connected to the hot water measuring hot water inlet pipe of the hot water side heat exchanger through the water inlet pipe of the hot water side heat exchanger , the hot water side cold water outlet pipe of the hot water side heat exchanger is connected to the flue gas side cold water outlet pipe through the hot water side heat exchanger return pipe; the hot water side heat exchanger inlet pipe and the hot water side heat exchanger return water The heating medium passes through the pipeline;

The hot water side heat exchanger is also connected to the hot water side cold water inlet pipe and the hot water side hot water outlet pipe passing through the heated medium; the hot water side cold water inlet pipe of the hot water side heat exchanger is connected to the hot water The cold source pipe of the heat exchanger on the network side, and the hot water outlet pipe on the hot water side are connected to the water inlet pipe of the heating network heater;

Electric valves are provided on the inlet and outlet pipes connected to the hot water side heat exchanger through the heating medium and the heated medium.

The hot water side heat exchanger includes at least two arranged side by side.

The heat exchanger on the flue gas side is a water-to-water heat exchanger, and the hot fluid inlet pipe on the flue gas side is connected to the hot water outlet pipe of the air-water heat exchanger at the front.

Electric valves are installed on the inlet and outlet pipes connected to the heat exchanger on the flue gas side through the heating medium and the heated medium.

A regulating valve is arranged on the return water pipe of the hot water side heat exchanger.

Beneficial effects of the utility model: the system of the utility model can use the waste heat of the flue gas to supply heat to the unit during the heating period, which increases the heating capacity of the unit; it is sent to the condensed water after recovering the heat of the traditional flue gas, and squeezes out the low pressure Compared with the energy-saving effect of the 7th and 8th cylinder steam extraction, because this system discharges higher-quality medium-pressure cylinder exhaust steam, it can more effectively reduce the coal consumption of the unit for power generation and improve the energy utilization rate.

Description of drawings

Figure 1 is a schematic diagram of the system.

Among them, 101 is the flue gas side heat exchanger, 102 is the heating network side heat exchanger, 103 is the heating network side heat exchanger; Hot water inlet pipe on the gas side, 114 is the cold water outlet pipe on the flue gas side, 115 is the water inlet pipe of the heat exchanger on the hot water side, 116 is the return water pipe of the heat exchanger on the hot water side, and 132 is the cold water pipe on the heat network side. 133 is the water inlet pipe of the heating network heater; 121 is the cold source inlet valve of the raw water heat exchanger; 122 is the cold source outlet valve of the raw water heat exchanger; 123 is the heat source inlet valve of the raw water heat exchanger; 124 is the heat source outlet valve of the raw water heat exchanger, 125 is the heat source inlet valve of the newly added water water heat exchanger, 126 is the heat source outlet valve of the newly added water water heat exchanger, and 127 is the heat source outlet valve of the newly added water water heat exchanger , 128 is the newly added water-water heat exchanger heat source water outlet regulating valve, 129 is the newly added water-water heat exchanger cold source water inlet valve, 130 is the newly added water-water heat exchanger cold source water outlet valve, and 131 is the newly added water water Heat exchanger cold source water bypass valve.

Detailed ways

The utility model is described in further detail below in conjunction with accompanying drawing and specific embodiment.

The utility model provides a flue gas waste heat utilization heating system, the system includes the existing flue gas side heat exchanger 101, the flue gas side heat exchanger is connected to the flue gas side hot water inlet pipe 113 through the heating medium, It also includes the cold water pipeline at the outlet of the raw water heat exchanger, that is, the cold water outlet pipeline 114 on the flue gas side, the original unit condensate water inlet pipeline 111 passing through the heated medium, and the heated unit condensate return water pipeline 112 . Wherein, the heating medium is the hot water outlet after the heat exchange of the gas-water heat exchanger for gas-water heat exchange on the flue gas, that is, the hot fluid inlet pipe 113 on the flue gas side is connected to the hot water outlet pipe of the steam-water heat exchanger at the front , the heated medium is the condensed water of the unit.

In order to achieve the purpose of using the waste heat of the flue gas for heating, the utility model is also equipped with a hot water side heat exchanger, which is heated by the flue gas side heat exchanger 101 respectively through the water inlet and outlet pipes of the heating medium. The water inlet and outlet pipes of the medium are connected, so that the heat can be supplied by the waste heat of the flue gas during the heating period.

The above-mentioned flue gas side heat exchanger 101 and hot water side heat exchanger are all water-to-water heat exchangers.

Specifically, the flue gas side hot water inlet pipe 113 connected to the hot water outlet pipe of the air-water heat exchanger is connected to the hot water heat measurement of the hot water side heat exchanger through the hot water side heat exchanger water inlet pipe 115 The water supply pipe, the hot water side cold water outlet pipe of the hot water side heat exchanger is connected to the flue gas side cold water outlet pipe 114 through the hot water side heat exchanger return pipe 116, and the flue gas side cold water outlet pipe 114 is connected to the air-water heat exchange The cold water return pipe of the device is pressurized by the original water pump and then sent to the original air-water heat exchanger to recirculate and absorb the waste heat of the flue gas; the water inlet pipe 115 of the hot water side heat exchanger and the return water pipe of the hot water side heat exchanger What circulates in 116 is heating medium. That is, the flue gas side hot water inlet pipe 113 not only serves as the heating medium of the flue gas side heat exchanger 101, but also serves as the heating medium of the hot water side heat exchanger, and the cold water after the heat exchange of the heating medium of the hot water side heat exchanger The flow direction is exactly the same as the cold water flow direction of the flue gas side heater.

The hot water side heat exchanger is also connected to the hot water side cold water inlet pipe and the hot water side hot water outlet pipe passing through the heated medium; the hot water side cold water inlet pipe of the hot water side heat exchanger is connected to the heat network side for heat exchange The cold source pipeline 132 of the device, and the hot water outlet pipeline of the hot water side are connected to the water inlet pipeline 133 of the heating network heater.

Electric valves are installed on the inlet and outlet pipes passing through the heating medium and the heated medium connected to the hot water side heat exchanger, and electric valves are installed on the inlet and outlet pipes passing through the heating medium and the heated medium connected to the flue gas side heat exchanger 101. Equipped with electric valves.

A regulating valve 128 is provided on the return water pipe 116 of the hot water side heat exchanger to adjust the return water flow rate of the hot water side heat exchanger.

According to needs, multiple above-mentioned hot water side heat exchangers can be arranged in parallel, all connected to the flue gas side heat exchanger 101 . As shown in FIG. 1 , it is an embodiment in which the hot water side heat exchanger 102 and the hot water side heat exchanger 103 are arranged in parallel.

In the embodiment shown in Figure 1, it includes a flue gas side heat exchanger 101, a heat network side heat exchanger 102 and a heat network side heat exchanger 103, a flue gas side hot water inlet pipe 113, and a flue gas side cold water outlet pipe 114. Hot water side heat exchanger inlet pipe 115, hot water side heat exchanger return water pipe 116, unit condensate water inlet pipe 111, unit condensate return water pipe 112, heat network side heat exchanger cold source pipe 132 , Heat network heater water inlet pipe 133 and supporting valves 121-131.

The above-mentioned flue gas side heat exchanger 101 , heat network side heat exchanger 102 and heat network side heat exchanger 103 are all water-to-water heat exchangers.

The heat exchanger 101 on the flue gas side is an existing conventional water-water heat exchanger, and the heating medium is the incoming hot water after exchanging heat between the air-water heat exchanger at the front and the flue gas, and the incoming hot water passes through the flue gas side The hot water incoming pipe 113 is input into the flue gas side heat exchanger 101 as a heating medium, and the heated medium in the flue gas side heat exchanger 101 absorbs the hot water incoming through the flue gas side hot water incoming pipe 113 High-temperature water heat is used to heat the condensate temperature of the main engine as the heated medium, thereby reducing the steam extraction volume of the low-pressure cylinder of the main engine, so as to use the waste heat of the flue gas to increase the steam volume of the main engine to do work.

The heating network side heat exchanger 102 and the heating network side heat exchanger 103 also use the hot water after heat exchange with the flue gas by the air-water heat exchanger installed at the front as the heating medium to heat the return water of the municipal heating network. Specifically, the incoming hot water after exchanging heat between the air-water heat exchanger installed at the front and the flue gas enters the hot water side heat exchanger 102 and the hot water side heat exchanger through the hot water side heat exchanger inlet pipe 115 respectively. The water inlet pipe of the device 103, the cold water after heat exchange converges through the water outlet pipe, and then enters the cold water outlet pipe 114 on the flue gas side through the return water pipe 116 of the heat exchanger on the hot water side and flows out. The utility model heats the return water of the municipal heating network by absorbing the heat of high-temperature water after heat exchange with the flue gas, thereby reducing the high-quality heating and extraction steam volume of the main engine, achieving the use of the waste heat of the flue gas, and increasing the amount of working steam of the main engine.

The above-mentioned return water pipeline 116 of the hot water side heat exchanger is provided with a newly added water-water heat exchanger heat source water outlet valve 127 and a newly added water-water heat exchanger heat source water outlet regulating valve 128, which can adjust the water outlet of the pipeline, and at the same time The water output can be adjusted.

For the heat network side heat exchanger 102 and the heat network side heat exchanger 103, considering the change of the power generation load of the unit, the waste heat of the flue gas fluctuates greatly, and two water-to-water heat exchangers with 50% capacity can be used, and the smoke exhaust rate of the unit can be adjusted accordingly. For heat, put one or two heat exchangers into operation.

The hot water outlet pipe and the cold water return pipe of the gas-water heat exchanger are respectively connected to the hot water inlet pipe 113 on the flue gas side and the cold water outlet pipe 114 on the flue gas side, and the flue gas heat is mainly transferred to the The water side, and then release the heat to the heat demand side through the pipeline through the flue gas side heat exchanger.

The unit condensate water inlet pipe 111 and the unit condensate return water pipe 112 of the flue gas side heat exchanger are conventional condensate water pipes that absorb the heat of the flue gas and then send it to the main engine condensate water pipe to reduce the main engine extraction of the low-pressure heater, thereby increasing the unit Do work and reduce the coal consumption of the unit for power generation.

The cold source pipe 132 of the heat network side heat exchanger of the heat network side heat exchanger and the water inlet pipe 133 of the heat network heater are newly added pipes, and the cold source pipe 132 of the heat network side heat exchanger is the return water pipe of the heat network system. The water inlet pipe 133 of the heat network heater is the water inlet pipe sent to the original conventional heat network heater, the cold source pipe 132 of the heat exchanger on the heat network side, and the water inlet pipe 133 of the heat network heater absorb the heat of the flue gas The return pipe of the municipal heating network reduces the high-quality heating extraction of the main engine, thereby increasing the work of the unit and reducing the coal consumption of the unit for power generation. The cold source pipe 132 of the heat network side heat exchanger of the heat network side heat exchanger, the water outlet pipe 133 of the heat network heater and the original conventional heat network heater pipeline are connected in series. The temperature generally rises to about 70°C, and then the return water of the heat network is heated up to 120 or 130°C by a conventional heat network heater and then sent to the heat user.

The return water pipeline 116 of the hot water side heat exchanger is provided with a regulating valve 128, which can switch and adjust the water side pipeline to ensure that the flue gas side heat exchanger 101 is switched to the heat network side heat exchanger 102 and the heat network side during the heating period. Heat exchanger 103 operates.

When the return water pipes 117 and 118 of the heating network are started or the heat exchanger equipment on the heating network side is overhauled, the electric valve 131 of the cold source water bypass valve of the newly added water-to-water heat exchanger goes through the bypass system to ensure the stable operation of the unit’s heating. Because the heating season is generally 4-6 months, the bypass pipeline needs to be used for pipeline flushing at the initial stage of operation, and the return water of the heating network can be fed into the heating network heater after the water quality is in compliance. The water outlet end of the bypass pipe is connected to the water inlet pipe of the original conventional heating network heater, and the water inlet end is connected to the water side inlet of the original conventional heating network heater.

The working principle of the system shown in Figure 1 is:

The hot water measuring heat exchanger of the utility model is arranged in parallel with the original flue gas side heat exchanger. During the non-heating period, when the system is in normal operation, the unit condensate water inlet pipe 111, unit condensate return water pipe 112, smoke The hot water inlet pipe 113 on the gas side and the cold water outlet pipe 114 on the flue gas side are in operation, the water inlet pipe 115 of the heat exchanger on the hot water side and the return pipe 116 of the heat exchanger on the hot water side are out of service to ensure that the unit can be used effectively Flue gas residual heat.

During the heating period, the hot water side heat exchanger 102 and the hot water side heat exchanger 103 return water pipes 132 and 133 of the heating network system are first put into operation, and then the water inlet pipe 115 of the hot water side heat exchanger and the hot water side heat exchanger are replaced. The heater return water pipe 116 is filled with water, the water source comes from the flue gas side hot water pipe 113, and then the hot water from the flue gas side hot water pipe 113 is switched to the hot water side heat exchanger water inlet Pipeline 115 and return water pipe 116 of the hot water side heat exchanger.

The water in the above-mentioned water inlet pipe 115 of the hot water side heat exchanger and the return water pipe 116 of the hot water side heat exchanger comes from the outlet pipe of the original air-water heat exchanger of the system, that is, the hot water inlet pipe 113 on the flue gas side In order to avoid pipeline vibration when the system is put into operation, after the cold source side inlet pipe 132 and cold source side outlet pipe 133 of the hot water side heat exchanger 102 and hot water side heat exchanger 103 are put into operation, Just open the heat source water inlet valve 125 of the newly added water-to-water heat exchanger, the heat source water outlet valve 126 of the newly added water-to-water heat exchanger, and then open the water-filled side heat exchanger water inlet pipeline 115 and the hot water side heat exchanger Return water pipeline 116. Usually, the electric valve 124 is closed only after the deviation between the pressure of the return water pipe 116 of the heat exchanger on the hot water side and the pressure of the cold water outlet pipe 114 on the flue gas side is kept within 0.1 MPa, so as to avoid the vibration of the cold water outlet pipe 114 on the flue gas side.

Specifically, the regulating valve 128 provided on the return water pipe 116 of the hot water side heat exchanger is adjusted to ensure that the original flue gas side heat exchanger 101 of the flue gas side hot water inlet pipe 113 and the flue gas side cold water outlet The pipeline 114 is switched without disturbance to ensure safe operation. Through the operation of the hot water measuring heat exchanger 102 and the hot water measuring heat exchanger 103, it can absorb the waste heat of the flue gas to heat the return water of the heat network through the heat network return water pipe 117, increase the heat supply capacity of the unit, and reduce the coal consumption of the unit for power generation; At this time, the raw water water heat exchanger heat source water inlet valve 123 and the raw water water heat exchanger heat source water outlet valve 124 connected to the heating medium inlet and heating medium outlet pipes of the flue gas side heat exchanger 101 are closed, The cold source water inlet valve 121 of the raw water heat exchanger and the cold source water outlet valve 122 of the raw water water heat exchanger on the unit condensate water inlet pipe 111 and the unit condensate return water pipe 112 are also closed; the hot water side heater 102 and the hot water side heater The heating medium outlet pipeline, the heating medium inlet pipeline, the heated medium outlet pipeline, and the heated medium inlet pipeline of the water side heater 103 are newly added water-to-water heat exchanger cold source water inlet valve 129 and newly added water-to-water heat exchanger The cold source water outlet valves 130 are all opened.

The flue gas waste heat utilization heating system of the utility model can effectively utilize the flue gas waste heat and exert the working ability of high-quality steam, and reduce the coal consumption of the unit for power generation.

The logic control mode of the utility model can adjust the heat load according to the real-time change of the electric load or the heat supply load, so as to realize effective utilization of waste heat energy of the flue gas.

In the description of this specification, specific features, structures, materials or characteristics may be combined in any one or more embodiments or examples in an appropriate manner.

The above is only a specific embodiment of the present utility model, but the scope of protection of the present utility model is not limited thereto. Any skilled person in the art can easily think of changes or replacements within the scope disclosed by the present utility model. , should be covered within the protection scope of the present utility model.

Claims (5)

1. A flue gas waste heat utilization heating system, characterized in that it includes a flue gas side heat exchanger (101) and a hot water side heat exchanger, and the flue gas side heat exchanger is connected to the flue gas side heat exchanger passing through the heating medium. Water incoming pipe (113), flue gas side cold water outlet pipe (114), unit condensate water incoming pipe (111) passing through the heated medium, unit condensate return pipe (112); Among them, the flue gas side hot water inlet pipe (113) connected to the hot water outlet pipe of the air-water heat exchanger is connected to the hot water of the hot water side heat exchanger through the hot water side heat exchanger water inlet pipe (115). Measuring the hot water inlet pipe, the hot water side cold water outlet pipe of the hot water side heat exchanger is connected to the flue gas side cold water outlet pipe (114) through the hot water side heat exchanger return pipe (116); the hot water side heat exchanger The heating medium passes through the water inlet pipe (115) and the return water pipe (116) of the hot water side heat exchanger; The hot water side heat exchanger is also connected to the hot water side cold water incoming pipe and the hot water side hot water outlet pipe (118) passing through the heated medium; the hot water side cold water incoming water of the hot water side heat exchanger The pipe is connected to the cold source pipe (132) of the heat exchanger on the heating network side, and the hot water outlet pipe on the hot water side is connected to the water inlet pipe of the heating network heater (133); Electric valves are provided on the inlet and outlet pipes connected to the hot water side heat exchanger through the heating medium and the heated medium. 2 . The heat supply system for utilizing flue gas waste heat according to claim 1 , wherein the hot water side heat exchanger includes at least two arranged side by side. 3 . 3. A flue gas waste heat utilization heating system according to claim 1, characterized in that: the flue gas side heat exchanger (101) is a water-water heat exchanger, and the flue gas side hot water inlet pipe ( 113) Connect the hot water outlet pipe of the air-water heat exchanger at the front. 4. A flue gas waste heat utilization heating system according to claim 1, characterized in that: the inlet and outlet pipes connected to the flue gas side heat exchanger (101) through the heating medium and the heated medium are provided with electric valve. 5. A heat supply system utilizing flue gas waste heat according to claim 1, characterized in that: a regulating valve (128) is set on the return water pipe (116) of the hot water side heat exchanger.