CN211650196U - Steam-driven water-feeding pump small-machine exhaust waste heat recycling device - Google Patents

Abstract

The utility model discloses a little quick-witted exhaust waste heat recovery utilizes device of steam-feed pump, including demineralized water input pipeline, little quick-witted condenser, circulating pump, air preheater export low temperature economizer, condensate water heat exchanger, heat exchanger bypass, air heater, overgrate air heater, condensate water pipeline, No. seven low pressure feed water heaters, No. six low pressure feed water heaters and No. five low pressure feed water heaters, the device can utilize the little quick-witted exhaust waste heat heating boiler's of feed pump air heater and overgrate air and unit condensate water.

Description

A device for recycling and utilizing waste heat from exhaust steam of a small steam-powered feed pump

technical field

The utility model relates to a waste heat recovery and utilization device, in particular to a waste heat recovery and utilization device for exhaust steam of a small machine of a steam-driven feed pump.

Background technique

The feed water pump is the equipment with the largest power in the thermal power unit. In recent years, in order to reduce the power consumption rate of the plant, the coal-fired power plant abandoned the electric feed pump scheme and replaced it with a small steam turbine to drive the induced draft fan. This measure has a good effect on reducing the power consumption rate of the plant. The small steam turbine that drives the feed water pump is referred to as the small feed pump machine for short, while the large steam turbine used in the thermal power plant to drive the generator is referred to as the large machine for short. Usually, the feed pump small machine has its own independent condenser. The function of the condenser is to use water (called circulating water) as a cooling medium, directly or indirectly contact with the steam discharged from the steam turbine, and condense the steam into water (called condensed water), and the heat is taken away by the circulating water.

The circulating water used for cooling the steam exhaust of the small machine of the feed pump is usually separated from the circulating water pipeline of the large machine. The condensed water obtained by condensing the exhaust steam of the small machine of the feed pump is usually transported to the condenser of the large machine by the water pump, and mixed with the condensed water of the large machine.

Low-temperature economizer is a common device for coal-fired power plants to reduce flue gas loss and recover flue gas waste heat. Its essence is a "flue gas-water" heat exchanger. The low temperature economizer is mainly composed of multiple groups of heating surface tube bundles. When the flue gas flows through here, the cold water in the tube bundle absorbs the heat of the flue gas, so that the temperature of the flue gas decreases and the temperature of the water increases. The structure of the low temperature economizer is shown in the figure above.

In order to prevent low-temperature corrosion (that is, acid corrosion) at the cold end of the air preheater, power plants often need to install primary air and secondary air heaters to increase the comprehensive temperature of the cold end and reduce the replacement of sulfuric acid vapor in the flue gas at the cold end. Condensation on thermal elements. The air heater is composed of multiple sets of tube bundles, and uses steam or hot water as a heat source to heat the primary air and secondary air (air) flowing through the tubes.

The steam discharged from the small machine of the feed pump carries high heat. After this part of the heat is taken away by the circulating water, it usually exchanges heat with the air directly or indirectly in the cooling tower and is lost to the atmosphere. If the waste heat of the exhaust steam of the feed pump is recycled, the heat of the flue gas at the inlet and outlet of the air preheater is synchronously recovered, and the above heat is used to heat the primary and secondary air of the boiler and the condensate water of the unit, which will undoubtedly significantly improve the overall performance of the unit. energy saving level.

Utility model content

The purpose of this utility model is to overcome the shortcomings of the above-mentioned prior art, and to provide a device for recycling the waste heat of steam exhausted by a small machine of a steam-driven feed pump, which can use the waste heat of a small machine of the feed pump to heat the primary air and secondary heat of a boiler. wind and condensed water from the unit.

In order to achieve the above purpose, the utility model for the recovery and utilization of the waste heat from the exhaust steam of the small engine of the steam-driven feed pump includes a demineralized water input pipeline, a small engine condenser, a circulating pump, a low-temperature economizer at the outlet of the air preheater, and a condensate water changer. Heater, heat exchanger bypass, primary air heater, secondary air heater, condensate pipeline, No. 7 low-pressure heater, No. 6 low-pressure heater and No. 5 low-pressure heater;

The demineralized water input pipeline and the outlet of the small-machine condenser are connected with the inlet of the circulating pump. The outlet of the circulating pump is divided into two paths after passing through the low-temperature economizer at the outlet of the air preheater, one of which is connected with the heat release of the condensate heat exchanger. The side inlet is connected, and the other is connected with the inlet of the heat exchanger bypass. The secondary air heater is communicated with the inlet of the small machine condenser;

The outlet of the condensed water pipeline is divided into two paths after passing through the No. 7 low-pressure heater, one of which is connected to the inlet of the heat-absorbing side of the condensed water heat exchanger, and the other is connected to the inlet of the No. 6 low-pressure heater, and the condensed water exchanges heat. The outlet of the heat-absorbing side of the heater and the outlet of the No. 6 low-pressure heater are all communicated with the inlet of the No. 5 low-pressure heater.

A bypass valve is provided on the bypass of the heat exchanger.

The inlet of the circulation pump is provided with a circulation pump inlet door, and the outlet of the circulation pump is provided with a circulation pump outlet door.

A demineralized water valve is arranged on the demineralized water input pipeline.

An inlet door is arranged at the inlet of the heat-absorbing side of the condensed water heat exchanger, and an outlet door is arranged at the outlet of the heat-absorbing side of the condensed water heat exchanger.

It also includes a small-machine steam exhaust pipe, wherein the small-machine steam exhaust pipe is communicated with the steam inlet of the small-machine condenser.

The utility model has the following beneficial effects:

In the specific operation, the utility model adopts the combined design of condenser + low temperature economizer + condensed water heat exchanger + hot water heater. The heat is used to heat the condensed water, primary air and secondary air without additional energy consumption, which significantly reduces the coal consumption of the unit and improves the efficiency of the unit. Specifically, the demineralized water is heated by the small-machine condenser and the low-temperature economizer at the outlet of the air preheater, and then the condensed water, the primary air and the secondary air are heated by the high-temperature demineralized water, so as to realize the heating by the waste heat of the exhaust steam of the small machine of the feed pump. The purpose of the primary air and secondary air of the boiler and the condensed water of the unit. In addition, it should be noted that the medium and low temperature economizer, the primary air heater and the secondary air heater are all arranged around the air preheater, and the condensed water heat exchanger and the condenser are arranged around the steam-driven feed pump , The pipeline is short, the layout is compact, the pipe material is saved, the resistance along the process is reduced, and the good circulation effect is guaranteed.

Description of drawings

Figure 1 is a schematic structural diagram of the utility model.

1 is the demineralized water valve, 2 is the inlet door of the circulating pump, 3 is the circulating pump, 4 is the outlet door of the circulating pump, 5 is the low temperature economizer at the outlet of the air preheater, 6 is the No. 7 low pressure heater, 7 is the inlet door, 8 No. 6 low-pressure heater, 9 is condensate heat exchanger, 10 is outlet door, 11 is No. 5 low-pressure heater, 12 is primary air heater, 13 is secondary air heater, 14 is bypass valve , 15 is a small machine condenser.

Detailed ways

Below in conjunction with accompanying drawing, the utility model is described in further detail:

Referring to Fig. 1, the utility model for the recovery and utilization of waste heat from the exhaust steam of a small engine of a steam-driven feed pump includes a demineralized water input pipeline, a small engine condenser 15, a circulating pump 3, a low-temperature economizer 5 at the outlet of the air preheater, a condensation Water heat exchanger 9, heat exchanger bypass, primary air heater 12, secondary air heater 13, condensate pipeline, No. 7 low-pressure heater 6, No. 6 low-pressure heater 8 and No. 5 low-pressure heater 11; The demineralized water input pipeline and the outlet of the small-machine condenser 15 are connected with the inlet of the circulating pump 3, and the outlet of the circulating pump 3 is divided into two paths after passing through the low-temperature economizer 5 at the outlet of the air preheater, one of which is connected to the condensed water. The heat release side inlet of the heat exchanger 9 is connected, and the other way is connected with the inlet of the heat exchanger bypass. The primary air heater 12 and the secondary air heater 13 are connected to the inlet of the small machine condenser 15; the outlet of the condensed water pipeline is divided into two paths after passing through the No. 7 low-pressure heater 6, one of which is connected to the condensed water. The inlet of the heat-absorbing side of the heat exchanger 9 is connected, and the other way is connected with the inlet of the No. 6 low-pressure heater 8. The outlet of the heat-absorbing side of the condensed water heat exchanger 9 and the outlet of the No. 6 low-pressure heater 8 are both connected to the No. The inlets of the low pressure heaters 11 are communicated. The utility model also includes a small-machine steam exhaust pipe, wherein the small-machine steam exhaust pipe is communicated with the steam inlet of the small-machine condenser 15 .

A bypass valve 14 is arranged on the bypass of the heat exchanger; a circulating pump inlet door 2 is arranged at the inlet of the circulating pump 3, and a circulating pump outlet door 4 is arranged at the outlet of the circulating pump 3; a demineralized water valve is arranged on the demineralized water input pipeline 1. An inlet door 7 is arranged at the inlet of the heat-absorbing side of the condensed water heat exchanger 9, and an outlet door 10 is arranged at the outlet of the heat-absorbing side of the condensed water heat exchanger 9.

The utility model uses demineralized water as a working medium to carry out a closed cycle, and the circulating power comes from the driving of the circulating pump 3. When preparing to put into use, firstly inject demineralized water, open the demineralized water valve 1 at this time, and the demineralized water enters the system. After filling with demineralized water, open the inlet door 2 of the circulating pump, start the circulating pump 3, open the outlet door 4 of the circulating pump, and the demineralized water in the system begins to circulate.

The demineralized water first enters the condenser 15 of the small machine, exchanges heat with the steam discharged from the small machine, cools the exhaust steam from the small machine and condenses it into condensed water, and the demineralized water absorbs the waste heat of the exhaust steam, and the water temperature rises.

After being pressurized by the circulating pump 3, the demineralized water flows through the low-temperature economizer 5 at the outlet of the air preheater, and the demineralized water is heated by the high-temperature flue gas, so that the temperature of the flue gas is lowered, the temperature of the demineralized water is increased, and the demineralized water enters the condensed water for heat exchange In the heat exchanger 9, part of the heat is transferred to the condensed water, and then enters the primary air heater 12. The condensed water output by the No. 7 low-pressure heater 6 enters the condensed water heat exchanger 9 to absorb heat and then enters the No. 5 low pressure. In the heater 11, the flow rate of the pipeline is adjusted through the inlet door 7 and the outlet door 10, or the condensed water heat exchanger 9 is deactivated. In the initial stage of the boiler ignition, the amount of flue gas is small. In order to ensure the temperature of the heater, The condensate heat exchanger 9 needs to be deactivated. At this time, the bypass valve 14 is opened, the inlet door 7 and the outlet door 10 are closed, the No. 6 low-pressure heater 8 is turned on, and the heat exchanger bypass is put into operation to reduce heat loss and ensure warm air first. heat supply to the appliance.

The high-temperature demineralized water entering the primary air heater 12 heats the primary air, then enters the secondary air heater 13 to heat the secondary air, and finally enters the small-machine condenser 15, and starts to cool down. One endothermic-exothermic cycle.

To sum up, in the present invention, the demineralized water passes through the steam-water and flue gas-water heat exchangers, and the waste heat is fully recovered, and then passes through the condensed water heat exchanger 9, the water-air heat exchanger, etc., to achieve condensed water, The increase of primary air and secondary air temperature reduces the coal consumption of the unit, improves the efficiency of the unit, and has a significant energy saving effect.

Claims (6)

1. a steam-driven feed pump small machine exhaust steam waste heat recovery and utilization device, is characterized in that, comprises demineralized water input pipeline, small machine condenser (15), circulating pump (3), air preheater outlet low temperature economizer (5), condensate heat exchanger (9), heat exchanger bypass, primary air heater (12), secondary air heater (13), condensate pipeline, No. 7 low pressure heater (6) , No. 6 low-pressure heater (8) and No. 5 low-pressure heater (11); The demineralized water input pipeline and the outlet of the small-machine condenser (15) are connected with the inlet of the circulating pump (3), and the outlet of the circulating pump (3) is divided into two paths after passing through the low-temperature economizer (5) at the outlet of the air preheater. , one of which is connected to the heat release side inlet of the condensate heat exchanger (9), the other way is connected to the inlet of the heat exchanger bypass, the heat release side outlet of the condensate heat exchanger (9) and the heat exchanger The outlet of the bypass is connected with the inlet of the small-machine condenser (15) through the primary air heater (12) and the secondary air heater (13) in turn after passing through the pipeline; The outlet of the condensed water pipeline is divided into two paths after passing through the No. 7 low-pressure heater (6), one of which is connected to the heat-absorbing side inlet of the condensed water heat exchanger (9), and the other is connected to the No. 6 low-pressure heater (8) The inlet of the condensate heat exchanger (9) and the outlet of the No. 6 low-pressure heater (8) are connected with the inlet of the No. 5 low-pressure heater (11). 2 . The device for recovering and utilizing waste heat from exhaust steam of a small machine of a steam powered feed pump according to claim 1 , wherein a bypass valve ( 14 ) is provided on the bypass of the heat exchanger. 3 . 3. The steam-driven feed pump small machine exhaust steam waste heat recovery and utilization device according to claim 1 is characterized in that, the inlet of the circulating pump (3) is provided with a circulating pump inlet door (2), and the circulating pump (3) is provided with a circulating pump inlet door (2). A circulating pump outlet door (4) is arranged at the outlet. 4. The device for recovering and utilizing waste heat from exhaust steam of a small machine of a steam-driven feed pump according to claim 1, characterized in that a desalinated water valve (1) is provided on the demineralized water input pipeline. 5. The device for recycling waste heat of exhaust steam from a small machine of a steam-driven feed pump according to claim 1, characterized in that, an inlet door (7) is provided at the inlet of the heat-absorbing side of the condensed water heat exchanger (9), and the condensed water heat exchanger (9) is provided with an inlet door (7). An outlet door (10) is provided at the outlet of the heat-absorbing side of the heat exchanger (9). 6. The device for recovering and utilizing the waste heat of the small-machine exhaust steam of a steam-powered feed pump according to claim 1, characterized in that it also comprises a small-machine exhaust pipe, wherein the small-machine exhaust pipe and the small-machine condenser (15) connected to the steam inlet.

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