CN108131709A - A kind of increasing steam turbine steam exhaust recycling pumps combining heating system with full hydro-thermal - Google Patents

Abstract

A combined heat supply system of steam generator exhaust steam recovery system and full water heat pump, including steam turbine, condenser or air cooling island, exhaust steam extraction system, exhaust steam recovery and utilization system, and full water heat pump system; it is characterized in that: combined heat supply The system consists of two water cycles: one is the hot water exchange cycle system, and the other is the external network heating network water cycle system, and the two are connected to each other for heat exchange; the full water heat pump system is used to greatly improve the exhaust steam utilization of the steam generator exhaust steam recovery system increase the energy saving at the cold end; thermal power plant units no longer need to raise the back pressure to operate; the supply and return water of the external network of the heat network and the heat exchange supply and return water are two completely different cycles, which greatly reduce the mutual coupling and mutual restriction.

Description

A Combined Heat Supply System of Steam Booster Waste Steam Recovery and All-Water Heat Pump

technical field

The invention belongs to the field of energy saving and emission reduction, and in particular relates to a combined heat supply system of a waste steam recovery system of a steam booster and an all-water heat pump.

Background technique

As we all know, the exhaust steam waste heat recovery system of the steam generator is more and more popular in the application of the first station system of the thermal power plant. At the same time, the application of all-water absorption heat pumps on the external heating network side of the heating system is becoming more and more popular.

First of all, the basic principle of the waste steam recovery system of the steam booster is: use the steam booster to suck the exhaust steam (slack steam) of the steam turbine, so that the exhaust steam is properly boosted and heated, and then sent to the heat network condenser to heat the heat exchange return water. The heat of the exhausted steam can be recovered and passed into the heat exchange return water, and at the same time, the temperature of the heat exchange return water will be appropriately increased. The entire heat exchange and return water heating system is "cascaded heating", and the temperature of the heat exchange and return water is gradually increased. The heat network condenser is used as the pre-heater of the entire heat exchange and return water heating system, and the last stage heater is the peak heater of the first station of the heat network. Through the waste steam recovery system of the steam generator, the heat of exhaust steam at the cold end of the steam turbine (latent heat of vaporization) can be recovered and utilized, which greatly reduces the loss at the cold end of the power plant, improves and improves the heat utilization rate and efficiency of the "power plant Rankine cycle", and achieves The effect of energy saving and emission reduction.

Secondly, the basic principle of the all-water absorption heat pump is that the three-way heat transfer medium is all water. The first way, the heat pump power source medium, uses hot water from power plants (or hot water or waste hot water from industrial enterprises), especially the water supplied by the first station of the heat network (its temperature can be controlled at about 125°C) as the power source, then the heat pump The body does not need to consume steam as its power source. Heat pumps can also be used in thermal power plants with insufficient exhaust steam or with low exhaust steam parameters. The scope of use of the heat pump can be expanded. The second way, the heat release and cooling medium of the heat pump uses hot water from power plants (or hot water or waste hot water from industrial enterprises), especially the water supplied by the first station of the heat network (using plate heat exchangers) after proper cooling and then used as the heat pump Exothermic cooling medium, then, thermal power plant units (especially water-cooled units) no longer need to increase the back pressure (increase the temperature of the condenser circulating water) to operate, and even no longer need the condenser circulating water or steam turbine exhaust steam as exothermic cooling medium. The third way, the heat-absorbing and heating-up medium of the heat pump, adopts the return water from the external network of the heat network. The water supply and return cycle of the external network of the heating network and the supply and return water cycle of the first station of the heating network are two completely different water cycles.

For the all-water absorption heat pump, the power source hot water and the exothermic cooling hot water are all taken from the high-temperature supply and outlet water of the first station of the heating network. The water supply and return cycle at the first station of the heating network is only established between the first station of the heating network and the heat pump. In this way, the water supply side of the first station of the heating network no longer needs to be transported to the heat exchange station on the city side for a long distance. The all-water absorption heat pump absorbs heat to raise the temperature of the water, and uses the external network of the heat network to return water. The water supply and return cycle of the external network of the heating network is a cycle established between the all-water heat pump system and the heat exchange station on the city side.

When using the steam booster to recycle exhaust steam from the steam turbine for heating, the lower the temperature of the return water at the first station, the greater the recovery and utilization of exhaust steam from the steam turbine. The use of all-water heat pumps can provide return water with a large temperature difference for the first station of the heating network, which can greatly increase the exhaust steam utilization of the steam generator exhaust steam recovery system and improve the energy saving of the cold end. The waste steam recovery system of the supercharger and the all-water absorption heat pump each have significant advantages. If the two can be effectively combined to give full play to their respective advantages and create operating conditions for each other, then the exhaust steam recovery of the power plant and the energy-saving benefits of the cold end will be greatly improved.

Contents of the invention

The purpose of the present invention is to provide a combined heat supply system of a steam booster waste steam recovery system and an all-water heat pump.

A combined heat supply system of steam generator exhaust steam recovery system and full water heat pump, including steam turbine, condenser or air cooling island, exhaust steam extraction system, exhaust steam recovery and utilization system, and full water heat pump system; it is characterized in that: combined heat supply The system consists of two water cycles: one is the hot water circulation system, the other is the external network heating network water circulation system, the two are connected to each other for heat exchange; the hot water circulation system is connected to the exhaust steam recovery system, including the exhaust steam condenser , steam generator condenser, hot water exchange circulation pipeline, and the hot water exchange circulation pipeline is connected to the exhaust steam condenser and steam generator condenser in turn, and the exhaust steam condenser and steam generator condenser are used to heat the water exchange medium ;The water circulation system of the external network heating network includes a full-water heat pump and the water circulation pipeline of the heating network; the water circulation pipeline of the water exchange circulation system is connected to the heat release side of the heat pump, and the water circulation pipeline of the heating network is connected to the heat absorption side of the heat pump , Heating the return water of the heating network.

Further, a combined heat supply method of a steam generator exhaust steam recovery system and an all-water heat pump is characterized in that:

(a1) The exhaust steam is drawn from the condenser of the main steam turbine, and the heat of the exhaust steam is recovered by the exhaust steam condenser and the steam booster condenser to perform a heating cycle for exchanging hot water;

(a2) The high-temperature water supply of the hot water exchange cycle is divided into two paths; one of the heat exchange high-temperature water supply is used as the power source medium of the heat pump; the other heat exchange high-temperature water supply is used as the heat release side medium of the plate heat exchanger to heat the external network for heat supply and low-temperature return water;

The cooled water from the power source of the heat pump merges with the heat-exchanged high-temperature supply water cooled in the plate heat exchanger, enters the cooling side of the heat pump, and continues to cool down in the heat pump; after that, it flows out of the cooling side of the heat pump to the heat exchange side. The water circulation system transports heat exchange low temperature return water.

The heat-exchanging low-temperature return water from the heat release and cooling side of the heat pump flows through the exhaust steam condenser and the steam generator condenser in the hot water exchange cycle in turn, and is heated to a suitable temperature by the heat network heater, and then distributed Two channels, delivering hot water to the power source of the heat pump heat pump and the plate heat exchanger, forming a cycle and reciprocating continuously;

(a3) The external grid heat supply and low temperature return water are divided into two paths. One of the low-temperature return water for external network heating is connected to the heat-absorbing and warming water inlet pipe of the heat pump, and the low-temperature return water for external network heating is heated in the heat pump; The water inlet pipes on the hot side are connected, and the low-temperature return water supplied by the external network is heated in the plate heat exchanger;

(a4) The effluent from the heat-absorbing and warming-up side of the heat pump is mixed with the effluent from the heat-absorbing side of the plate heat exchanger to provide a certain temperature of the external network for heating and high-temperature effluent to the external network of the heating network.

Compared with prior art, the beneficial effect of the present invention is:

1. When the steam generator is used to recycle the exhaust steam of the steam turbine for heating, the lower the temperature of the return water at the first station, the greater the recovery and utilization of the exhaust steam of the steam turbine. Using the all-water heat pump system to "create a large temperature difference return water" for the first station of the heating network can greatly increase the exhaust steam utilization of the steam generator exhaust steam recovery system and improve the energy saving of the cold end.

The waste steam recovery system of the supercharger and the all-water absorption heat pump have their own obvious advantages, and they are very mature. If the two can be effectively combined to give full play to their respective advantages and create operating conditions for each other, then the exhaust steam recovery of the power plant and the energy-saving benefits of the cold end will be greatly improved.

2. The exothermic and cooling medium of the heat pump is to properly cool the water supplied by the first station of the heating network (using a plate heat exchanger) and then use it as the exothermic and cooling medium of the heat pump. Then, the thermal power plant unit (especially the water-cooled unit) no longer needs to lift High back pressure (in order to increase the temperature of the condenser circulating water) operation, and even no longer need the condenser circulating water or exhaust steam of the steam turbine as the exothermic cooling medium.

3. The heat-absorbing and warming-up medium of the heat pump is the return water from the external network of the heating network. The "backwater supply to the external network of the heating network" and "the return water supply to the first station of the heating network" are two completely different cycles. The first station only supplies water to the heat pump. The "coupling and mutual restriction" between the return water temperature of the first station and the waste steam recovery and utilization system of the steam booster, the heat pump and the first station can be greatly slowed down.

Description of drawings

Figure 1 is a schematic diagram of the combined heating system of the waste steam recovery system of the supercharger and the all-water heat pump;

Among them, 1 medium exhaust steam of high back pressure steam turbine, 2 medium exhaust steam of low back pressure steam turbine, 3 low pressure cylinder of high back pressure steam turbine, 4 low pressure cylinder of low back pressure steam turbine, 5 condenser of high back pressure steam turbine, 6 low back pressure steam turbine Condenser, 7 steam booster, 8 heat network circulation outlet pipe, 9 heat network circulation return pipe, 10 heat network heater, 11 steam booster condenser, 12 second exhaust steam condenser, 13 first exhaust steam condenser Steam generator, 14 exhausted steam header, 15 exhausted steam header control valve, 16 heat pump cooling side, 17 heat pump heating side, 18 plate heat exchanger heat release side, 19 plate heat exchanger heat absorption side.

Detailed ways

The present invention will be further described below in conjunction with accompanying drawing 1. It should be understood that the content described here is only for illustration and explanation of the present invention, and is not intended to limit the present invention.

The technical scheme of the present invention is not limited by the capacity of the power plant unit.

The technical scheme of the present invention is not limited by the number of power plant units participating in exhaust steam recovery and heat supply.

The technical scheme of the present invention is not limited by the steam parameters of the power plant unit.

The technical scheme of the present invention is not limited by the exhaust steam cooling mode of the power plant unit.

The technical scheme of the present invention is not limited by the heat supply thermal system of the power plant.

Example 1: Air cooling unit

1. Steam generator waste steam recovery system

A power plant has two 600MW indirect air-cooled units installed. The exhaust steam of the two steam turbines is recycled by the steam booster at the same time.

Its waste steam recovery system for thermal power plants includes two steam turbines and corresponding two condensers, exhaust steam extraction system, and exhaust steam recovery and utilization system;

The two steam turbines have different operating back pressures, namely high back pressure steam turbine and low back pressure steam turbine. For example, two 600MW-class steam turbine units and two 600MW-class indirect air-cooling units operate at the same time. During winter operation, one of the steam turbines operates with a back pressure of 10.5KPa, and the other steam turbine operates with a back pressure of 20KPa. (10.5KPa and 20KPa are just examples for the convenience of description. Configuration methods of other parameters are also within the protection scope of the present application). The exhaust steam of both units is recycled.

Using the exhaust steam extraction system, holes are opened from the condenser of the 1#600MW steam turbine and the condenser of the 2#600MW steam turbine respectively, and the exhaust steam of the two indirect air-cooled units is drawn out, and transported to the exhaust steam header (main pipe) through pipelines ). The exhaust steam extraction system includes the exhaust steam extraction special parts, the exhaust steam extraction pipeline and the exhaust steam header (main pipe); the exhaust steam extraction special parts are fixedly installed on the throat side of the condenser, and the exhaust steam extraction special parts The exhaust steam outlet hole is arranged on the side plate of the throat, the reinforced structure is arranged on the inner side of the throat of the open condenser, and the exhaust steam deflector is arranged on the inner side of the exhaust steam outlet hole; The steam header; the exhaust steam outlet pipe is equipped with a control valve. The exhaust steam extraction system is to lead (direct air cooling, indirect air cooling, water cooling) steam turbine exhaust steam from the condenser or exhaust pipe, and control the amount of exhaust steam exhausted to the air cooling island or condenser.

There are valves on the exhaust steam header, forming a two-stage structure. One end is connected with 10.5KPa exhaust steam, and the other end is connected with 20KPa exhaust steam. They are the low-pressure section and the high-pressure section respectively. The high-pressure section is connected to the condenser of the high backpressure steam turbine through the exhaust steam outlet pipe, and the low pressure section is connected to the condenser of the low backpressure steam turbine through the exhaust steam outlet pipe. The valve on the exhaust gas header is controlled to open to realize a whole structure. The exhaust steam header is equipped with a control valve to facilitate the system to perform various adjustment operation modes.

The waste steam recovery and utilization system is equipped with a steam booster, the exhaust steam connection pipeline of the medium pressure cylinder of the high back pressure steam turbine is connected to the working (power) steam inlet of the steam booster, and the high pressure section connection pipeline of the exhaust steam header is connected to the suction steam port of the steam booster. The exhaust steam of the steam booster is connected to the steam (shell) side of the steam booster condenser; several steam boosters can also be connected in parallel to further increase the temperature and pressure of the steam or increase the operating flexibility.

Or, when the exhaust steam header is not used, the exhaust steam outlet pipe of the low back pressure steam turbine is directly connected to the first exhaust steam condenser, and the exhaust steam outlet pipe of the high back pressure steam turbine is directly connected to the second exhaust steam condenser; The exhaust steam outlet pipe of the steam turbine is also connected to the suction port of the exhaust steam recovery and utilization system, or the exhaust steam exhaust pipe of the low back pressure steam turbine is also connected to the exhaust steam outlet of the exhaust steam recovery and utilization system; the exhaust steam outlet of the exhaust steam recovery and utilization system is connected to The condenser of the steam generator; the combined hydraulic system is connected to the heating pipe network.

The steam booster is an adjustable steam booster, or a non-adjustable steam booster.

The power steam of the steam booster can also be the exhaust steam of the high-pressure cylinder of the steam turbine, or the steam extracted from the cold end (or hot end) of the boiler reheater.

2. Combined heating system

The entire combined heating system consists of two water cycles. One is the hot water exchange cycle at the first station, and the other is the external network heating network water cycle. The water circulation of the first station and the water circulation of the external network heating network are independent circulation systems, and they are connected to each other for heat exchange.

1. The hot water circulation system at the first station,

It belongs to the side of the power plant and is connected to the waste steam recovery system of the steam booster. The equipment involved includes: the first exhaust steam condenser, the second exhaust steam condenser, the steam booster condenser, the first station heater of the heating network, Water exchange system, supporting piping system (including pipes, valves, pipe fittings, supports and hangers, expansion joints, etc.).

The low pressure section of the exhaust steam header is connected to the steam (shell) side of the first exhaust steam condenser, and the high pressure section of the exhaust steam header is connected to the steam (shell) side of the second exhaust steam condenser. The exhaust steam from the medium-pressure cylinder of the high-backpressure steam turbine and the exhaust steam from the medium-pressure cylinder of the low-backpressure steam turbine are respectively connected to the heater at the first station of the heating network.

The heat exchange circulating water pipeline of the hot water exchange system passes through the first exhaust steam condenser, the second exhaust steam condenser, the steam booster condenser, and the heating network heater in sequence, and the heat exchange circulating water is heated and supplied to the whole water heat pump system.

The condensate pipes of each condenser are connected to the hot well of the steam exhaust device, and can also have an independent hot well.

After the exhaust steam of the indirect air-cooled unit is led to the exhaust steam header, according to the configuration of the heating condenser system and the matching of steam and water parameters, it is necessary to deal with the exhaust steam in the exhaust steam header for further utilization. Recovery of exhaust heat.

The waste steam is recovered through multiple processing.

A road: Low parameter (10.5KPa) exhausted steam directly enters the first exhausted steam condenser, which is used for heating and exchanging return water. The heat exchange return water temperature is 25°C. The exhaust steam of 10.5KPa can directly heat the return water for heat exchange. Heat the heat exchange return water at 25°C to raise the temperature by 12°C to 37°C. There is no need to deal with the drawn exhaust steam pressure.

Road B: The 20KPa exhaust steam can be used as a heat source to continue heating the 37°C water from the first exhaust steam condenser. Therefore, the exhaust steam at 20KPa directly enters the second exhaust steam condenser to heat the exchange water at 37°C to raise the temperature by 21°C to 58°C. There is no need to deal with the drawn exhaust steam pressure.

Route C: In order to further improve the heat utilization rate of the exhaust steam, the pressure of the exhaust steam can be increased appropriately through a steam booster (or other methods), and then the temperature of the steam is increased, and then heated and exchanged for return water. Utilize the exhaust steam of the medium pressure cylinder of the high back pressure steam turbine as the power steam of the steam booster, suck the 20KPa exhaust steam (exhaust steam) from the high pressure section of the exhaust steam header, and the 45KPa exhaust steam of the steam booster enters the condenser of the steam booster as the second heat exchange return water The three-stage heater continues to heat the heat exchange backwater to raise the temperature by 20°C to 78°C.

So far, the exhaust steam in the exhaust steam header enters different condensers to heat the heat exchange return water with three parameters of 10.5KPa, 20KPa, and booster boost to 45KPa, and the heat exchange return water is heated from 25°C to 78°C.

The exchange water at 78°C enters the heater at the first station of the heating network for fourth-stage heating. After four-stage heating, the exchanged water reaches 120°C and is sent to the external network heating network water circulation system.

The system works as follows:

The exhaust steam of two (1# and 2#) steam turbines is drawn out from the exhaust pipe or the throat of the condenser.

The exhausted steam of 1# steam turbine enters the first exhausted steam condenser, which is used as the first-stage heater to heat and exchange the return water to raise its temperature to a certain temperature. The exhaust steam of 2# steam turbine enters the exhaust second exhaust steam condenser, which is used as the second stage heater to continue heating the heat exchange return water to make it heat up again to a certain temperature.

Utilize the exhaust steam from the medium-pressure cylinder of 2# steam turbine as the power steam of the steam generator, and extract the exhaust steam (exhausted steam) from the low-pressure cylinder of the 2# steam turbine, and the exhaust steam of the steam generator enters the condenser of the steam generator as the third stage of heat exchange return water The heater continues to heat the heat-exchanging return water to make it heat up again to a certain temperature.

When the heating season is running, the heater at the first station of the heating network at the first station belongs to the fourth-level heater. After four-stage heating, the exchanged water reaches the required temperature and is sent to the external network heating network water circulation system.

The multi-stage heated condenser system operates as follows:

The water system of the three condensers is connected in series and can be operated in series, that is, the heat exchange return water of the heat network flows through the first exhaust steam condenser, the second exhaust steam condenser, the steam generator condenser, and the water The system water temperature gradually increases.

The water systems of the three condensers have bypass pipelines respectively, and can also be operated by bypass, that is, after the heat exchange return water flows through the first exhaust steam condenser, it is condensed from the second exhaust steam condenser and the steam booster. Bypass the heater, directly flow into the heater at the first station of the heat network, or the heat exchange return water of the heat network does not flow through the first exhaust steam condenser, directly enters the second exhaust steam condenser, and bypasses the steam generator condenser, Then it flows into the heater at the first station of the heating network, or the heat exchange return water does not flow through the first exhaust steam condenser and the second exhaust steam condenser, but directly enters the condenser of the steam generator, and then flows into the heater at the first station of the heating network.

If the steam turbine operating at 10.5KPa back pressure is overhauled, there will no longer be 10.5KPa back pressure exhaust steam in the exhaust steam header. Then, the first exhaust steam condenser is disconnected. Heat exchange return water can flow through the first exhaust steam condenser, but it will not be heated up. The heat exchange return water can also bypass the first exhaust steam condenser. The heat exchange return water is heated up in the second exhaust steam condenser and the steam booster condenser, and the temperature value will change. This is a variable working condition operation, the temperature gap is made up by the heater at the first station of the heating network, and the steam extraction volume of the steam turbine will increase appropriately.

If the steam turbine running at 20KPa back pressure is overhauled, there will no longer be 20KPa back pressure exhaust steam in the exhaust steam header. There are two system configurations and modes of operation.

In the first operation mode, the second exhaust steam condenser and the steam generator condenser are disconnected, and the heat exchange return water flows through or bypasses the second exhaust steam condenser and the steam generator condenser Condenser, steam booster condenser, heat exchange return water heating system changed from four levels to two levels, namely: the first exhaust steam condenser, the heater at the first station of the heating network, the second exhaust steam condenser, the booster The temperature deficiency caused by the decoupling of the steam turbine condenser is compensated by the heater at the first station of the heating network, and the steam extraction volume of the steam turbine is appropriately increased.

In the second operation mode, the second exhaust steam condenser is disconnected, the heat exchange return water flows through or bypasses the second exhaust steam condenser, and the heat exchange return water heating system consists of four The first stage becomes three stages, namely: the first exhaust steam condenser, the steam booster condenser, the heater at the first station of the heating network, and the temperature deficiency caused by the decoupling of the second exhaust steam condenser is compensated by the heater at the first station of the heating network , the steam extraction volume of the steam turbine is appropriately increased; at this time, the power steam and exhaust steam of the steam booster come from the running low back pressure steam turbine, and the low back pressure steam turbine is adjusted to high back pressure operation.

If both steam turbines are overhauled, the heating will be stopped accordingly.

2. The water circulation of the external network heating network,

It belongs to the external heating network side, and the equipment involved includes: full water heat pump, plate heat exchanger, pipeline valve piping system, etc. The all-water heat pump and plate heat exchanger are built on the side of the external heat network.

The whole water heat pump system is used as the key equipment of the external network of the heating network.

The high temperature (about 125°C) water supply of the heater at the first station of the heating network is divided into two routes. Among them, the high-temperature water supply at the first station of the heat network is used as the power source medium of the heat pump, and is connected to the water inlet pipe of the heat pump power source; the high-temperature water supply at the first station of the other heat network is used as the heat release side medium of the plate heat exchanger, and is connected to the heat release side of the plate heat exchanger. It is used to heat the low-temperature hair (about 60°C) return water of the external network in the heat-absorbing side of the plate heat exchanger. The flow ratio of the high-temperature water supply at the first station of the two-way heating network is based on the premise of satisfying the effective operation of the heat pump system.

The water outlet pipe of the heat pump power source merges with the outlet pipe on the heat release side of the heat exchanger and is connected to the water inlet pipe on the heat release and cooling side of the heat pump, and the outlet pipe on the heat release and cooling side of the heat pump is connected to the first exhaust steam condenser of the first station water exchange circulation system; cooling (about 65°C), the heat pump power source outlet water merges with the heat exchange water (about 63.8°C) cooled in the plate heat exchanger (about 63°C), enters the heat release and cooling side of the heat pump, and continues to release heat and cool down in the heat pump , After that, it flows out of the heat release and cooling side of the heat pump, and delivers low temperature (about 25°C) return water to the hot water exchange circulation system of the first station.

The return water with a large temperature difference (temperature dropped from about 125°C to about 25°C) from the heat release and cooling side of the full water heat pump flows through the first exhaust steam condenser and the second exhaust steam condenser in the hot water exchange cycle system of the first station in sequence The steam generator and the steam generator condenser are heated to about 125°C by the heater at the first station of the heating network, and then divided into two routes to deliver hot water to the power source of the full water heat pump heat pump and the plate heat exchanger to form a cycle. Keep going back and forth.

The return water (about 60°C) of the heating external network is divided into two paths. One of the return water from the external network is connected to the water inlet pipe on the heat-absorbing side of the heat pump, and the return water from the external network is heated to about 110°C in the heat pump; the other return water from the external network is connected to the heat-absorbing side of the plate heat exchanger. The pipes are connected, and the return water of the external network is heated in the plate heat exchanger (to about 122°C); after that, the water outlet pipe on the heat-absorbing side of the heat pump (temperature about 110°C) and the water outlet pipe on the heat-absorbing side of the plate heat exchanger (Temperature about 122°C) After merging, connect the water outlet of the heating external network to supply hot water at a certain temperature (about 113°C) to the heating external network.

The heating system of the whole combined heating system consists of two water cycles. The hot water exchange cycle at the first station only circulates between the waste steam recovery system of the supercharger and the full water heat pump, and the route is relatively short.

The temperature of the heat exchange return water at the first station is controlled at 25°C, and this temperature basically does not follow the atmospheric temperature. In this way, the temperature of the incoming heat exchange return water has the following characteristics: Compared with other systems, if it is the beginning and end of heating, the return water temperature is relatively high during actual operation (such as 40°C, 45°C), which is greater than 25°C; if it is heating In the deep cold period, the return water temperature is higher during actual operation (such as 55°C, 60°C). In this system, the temperature of the heat exchange return water at the first station is controlled at around 25°C, which realizes 1. The temperature is relatively low; 2. The temperature basically does not change with the change of the atmospheric temperature.

The heat exchange return water of the first station flows into the first exhaust steam condenser for heat exchange. Assume that the heat exchange end difference of the first exhaust steam condenser is 2.8°C, and the temperature rise of the condenser is 15°C. Then, the exhaust steam temperature entering the condenser = 25 + 15 + 2.8 = 42.8°C, and the corresponding exhaust steam saturation pressure is 8.5KPa.a. This pressure is the running back pressure of the steam turbine.

If other heating systems are used, the temperature of the heat exchange return water at the first station shall be 50°C. The heat exchange return water of the first station flows into the first exhaust steam condenser for heat exchange. Assume that the heat exchange end difference of the first exhaust steam condenser is 2.8°C, and the temperature rise of the condenser is 15°C. Then, the exhaust steam temperature entering the condenser = 50 + 15 + 2.8 = 67.8°C, and the corresponding exhaust steam saturation pressure is 28.4KPa.a. This pressure is the running back pressure of the steam turbine.

When the heat exchange return water temperature of the first station is 25°C, the operating back pressure of the steam turbine is 8.5KPa.a, and the waste steam recovery system of the steam booster can be effectively implemented. The utilization range of exhaust steam is wide, the impact on the power generation of the unit is small, and the recovery of exhaust steam is large. Moreover, it has strong applicability for direct air cooling, indirect air cooling and water cooling units.

With the increase of the heat exchange return water temperature of the first station, for example, when it reaches 50°C, the running back pressure of the steam turbine must reach 28.4KPa.a, it is difficult to implement the waste steam recovery system of the steam booster, and the range of exhaust steam utilization is narrow, which will affect the power generation of the unit The volume has a great influence, and the recovery volume of exhaust steam is small. Moreover, for the water-cooled unit, the waste steam recovery system of the supercharger lacks applicability.

From the above comparison, it can be seen that when the exhaust steam of the steam turbine is recovered and utilized for heating by the steam booster, the lower the return water temperature of the first station is, the greater the exhaust steam recovery and utilization of the steam turbine will be. Utilizing the all-water heat pump system can provide return water with a large temperature difference for the first station of the heating network, which can greatly increase the utilization of exhaust steam, increase the energy saving at the cold end, and greatly improve the energy-saving benefit.

If only one heating network water cycle is formed in the whole heating system. The heat exchange return water (design temperature is about 55°C) flows through the full water heat pump, the first exhaust steam condenser, the second exhaust steam condenser, the steam generator condenser and the full water The heat pump passes through the first station of the heating network, and is heated to about 125°C by the peak heater, and then divided into two routes to deliver hot water to the heat pump power source of the full water heat pump and the municipal external network, forming a cycle and constantly reciprocating.

The heat exchange return water enters the heat pump for the first time as a heat release cooling medium; the heat network water enters the heat pump for the second time as an endothermic heating medium. In this heating system, the return water temperature is greatly affected by the air temperature. Assuming that the design return water temperature is 55°C, the corresponding first station water supply temperature is 120°C. This working condition corresponds to the cryogenic period. At this point, the system is functioning normally. If it is the beginning and end of the heating period, the temperature is high, and the return water temperature is less than 55°C (for example, 40°C) during actual operation, corresponding to the first station water supply temperature of 70-80°C. The power of the all-water heat pump is insufficient, the efficiency of the heat pump is too low, and the entire heating system cannot be operated.

Combined heating system The heating system consists of two water cycles, and the full water heat pump technology can be used to provide return water with a large temperature difference for the first station of the heating network, which can greatly increase the utilization of exhaust steam, improve the energy saving of the cold end, and save energy. There will be a big improvement. At the same time, it also ensures that the return water temperature is less affected by the environment, and the heating system can operate reliably throughout the heating period.

Embodiment 2: Water-cooled unit

A power plant installed two 300MW water-cooled units. The exhaust steam of the two steam turbines is recycled by the steam booster at the same time. Similar to the air-cooling unit in Embodiment 1, the all-water absorption heat pump is used as the key equipment outside the heating network. The entire combined heating system consists of two water cycles. One is the hot water exchange cycle at the first station, and the other is the external network heating network water cycle.

Finally, it should be noted that: the above is only an explanation of the present invention, and is not intended to limit the present invention. Although the present invention has been described in detail, for those skilled in the art, it can still understand the aforementioned techniques The plan shall be modified, or some of the technical features shall be equivalently replaced. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims (10)

1. a kind of increasing steam turbine dead steam recovery system and full hydro-thermal pump combining heating system, including steam turbine, condenser or Air-Cooling Island, Steam exhaust extraction system, steam exhaust recycling system, full hydro-thermal pumping system；It is characterized in that：Combining heating system is followed there are two water Ring forms：One is heat-exchanging water-circulation system, the other is outer net heat supply network water circulation system, the two interconnection exchanges heat； Heat-exchanging water-circulation system is connected with each other with dead steam recovery system, including steam exhaust condenser, increases steam turbine condenser, heat-exchanging water-circulation pipe Road, heat-exchanging water-circulation pipeline are sequentially ingressed into steam exhaust condenser, increase steam turbine condenser, using steam exhaust condenser, increase steam turbine condenser Heating heat exchange aqueous medium；Outer net heat supply network water circulation system includes full hydro-thermal pumping system, heat supply heat supply network water circulation pipe；Heat-exchanging water follows The heat-exchanging water-circulation pipeline access heat pump cold side of loop system, heat supply heat supply network water circulation pipe access heat pump heat absorbing side, heating supply Heat supply network return water.

2. increasing steam turbine dead steam recovery system according to claim 1 pumps combining heating system with full hydro-thermal, which is characterized in that Heat-exchanging water-circulation system further includes heat exchangers for district heating；Heat exchange cycle water lines successively by steam exhaust condenser, increase steam turbine condenser, Heat exchangers for district heating, heat exchangers for district heating outlet pipeline connection heat pump cold side water inlet pipe.

3. increasing steam turbine dead steam recovery system according to claim 2 pumps combining heating system with full hydro-thermal, which is characterized in that Another way heat exchangers for district heating outlet pipe connects heat pump power source inlet channel, the power source medium as heat pump.

4. increasing steam turbine dead steam recovery system according to claim 3 pumps combining heating system with full hydro-thermal, which is characterized in that Heat pump power source outlet conduit imports heat pump cold side water inlet pipe.

5. increasing steam turbine dead steam recovery system according to claim 2 pumps combining heating system with full hydro-thermal, which is characterized in that Outer net heat supply network water circulation system further includes plate heat exchanger, plate heat exchanger cold side access heat exchangers for district heating outlet pipeline.

6. increasing steam turbine dead steam recovery system according to claim 5 pumps combining heating system with full hydro-thermal, which is characterized in that Heat supply hot net water water return pipeline accesses heat pump heat absorbing side all the way；Another way accesses plate heat exchanger heat absorbing side.

7. increasing steam turbine dead steam recovery system according to claim 6 pumps combining heating system with full hydro-thermal, which is characterized in that Heat pump heat absorbing side outlet pipe and heat exchanger heat absorbing side outlet pipe connect outside networks of heat supply outlet pipe after converging.

8. increasing steam turbine dead steam recovery system according to claim 1 pumps combining heating system with full hydro-thermal, which is characterized in that The setting of steam exhaust recycling system increases steam turbine, turbine discharge connecting line to the power steam entrance for increasing steam turbine, and steam exhaust is drawn For connecting line to the suction steam ports for increasing steam turbine, the steam discharge connecting line for increasing steam turbine extremely increases steam turbine condenser vapour side.

9. increasing steam turbine dead steam recovery system according to claim 1 pumps combining heating system with full hydro-thermal, which is characterized in that With two different steam turbines, there are different operation back pressures, respectively high back pressure steam turbine, low back pressure turbine；It draws respectively weary Vapour is pipelined to steam exhaust header；Heat-exchanging water-circulation system includes the first steam exhaust condenser, the second steam exhaust condenser；Steam exhaust Header divides two-way pipeline to connect the first steam exhaust condenser, the second steam exhaust condenser；Steam exhaust header is equipped with valve, forms two sections of knots Structure；Respectively high pressure section and low pressure stage, high pressure section connection high back pressure turbine condenser, low pressure stage connect low back pressure turbine and coagulate Vapour device；Valve is opened by control and adjusted.

10. a kind of increasing steam turbine dead steam recovery system pumps cooperation heat supply method with full hydro-thermal, it is characterised in that：

(a1) steam exhaust is drawn from main steam turbine condenser, using steam exhaust condenser, increases steam turbine condenser recycling steam exhaust heat exchange Hot water carries out heat cycles；

(a2) heat-exchanging water-circulation high temperature water supply is divided into two-way；The power source medium that wherein heat exchange high temperature supplies water as heat pump all the way； Another way heat exchange high temperature supplies water as plate heat exchanger cold side medium, to heat outer net heat supply low-temperature return water；

Heat pump power source water outlet after cooling converges with the heat exchange high temperature water supply after cooling down in plate heat exchanger, is put into heat pump Heat release cooling is continued in heat drop temperature side in heat pump；Later, outflow heat pump heat release cooling side is changed to the conveying of heat-exchanging water-circulation system Hot low-temperature return water.

The heat exchange low-temperature return water come out from heat pump heat release cooling side, flows successively through the steam exhaust condenser in heat-exchanging water-circulation, increases vapour Machine condenser is heated to suitable temperature using heat exchangers for district heating, then divides two-way, to heat pump heat supply pump power source and Plate heat exchanger conveys hot water, forms cycle, constantly reciprocal；

(a3) outer net heat supply low-temperature return water is divided into two-way.The wherein heat absorption heating water inlet of outer net heat supply low-temperature return water and heat pump all the way Pipeline is connected, and outer net heat supply low-temperature return water is heated up in heat pump；Another way outer net heat supply low-temperature return water is changed with board-like Hot device heat absorbing side inlet channel is connected, and outer net heat supply low-temperature return water is heated up in plate heat exchanger；

(a4) the heat absorption heating side water outlet of heat pump is mixed with the water outlet of plate heat exchanger heat absorbing side, and certain temperature is provided to heat supply network outer net Outer net heat supply high-temperature water outlet.