Cascade recycling system for waste heat of compressor station

Abstract

The utility model provides a compressor station waste heat cascade recycling system which comprises a compressor station engine unit, a waste heat boiler, a steam generator set, an air preheater, a phase change type smoke processor and a heat pump unit, the waste heat boiler receives smoke waste heat of the compressor station engine unit to generate steam, and the steam generator set generates electricity; the air preheater receives flue gas waste heat of the waste heat boiler to preheat external cold air, and the compressor station engine unit mixes the preheated hot air with natural gas for combustion to provide gas conveying pressure for the natural gas pipeline. The phase change type smoke processor receives smoke waste heat of the air preheater and exchanges heat with circulating water of the heat pump unit to supply heat to heating equipment. According to the scheme, gradient utilization of medium-high temperature flue gas waste heat power generation, medium-temperature flue gas combustion air preheating and low-temperature flue gas heating is achieved, direct emission of flue gas waste heat is avoided, station power consumption and fuel gas consumption are reduced, and the energy utilization efficiency is effectively improved.

Description

Technical Field

[0001] The utility model relates to the field of natural gas waste heat recovery, and in particular to a compressor station waste heat cascade recovery and utilization system. Background Art

[0002] Compressor stations are set up at certain intervals on long-distance natural gas pipelines to ensure the natural gas transmission pressure. At present, there are a large number of fuel-driven engine units on domestic long-distance natural gas pipeline compressor stations. The fuel is the natural gas used by the station itself, and the exhaust gas temperature after combustion can reach 550°C. At present, the flue gas of most compressor stations is directly discharged into the air, causing environmental pollution and energy waste. The cascade recovery and utilization of the waste heat of the compressor station engine unit can improve energy utilization and have good environmental and economic benefits.

[0003] At present, most of the waste heat recovery of compressor stations in China is to recover part of the flue gas waste heat for power generation or for heating of the station itself. After the flue gas waste heat is used for power generation, the exhaust temperature can reach about 180℃. At present, most of them are directly discharged, and a considerable amount of heat is still wasted. The use of flue gas waste heat for heating is mostly due to the limited heating demand of the compressor station itself, and the geographical location of the compressor station is usually remote, and the surrounding heat load demand is also small. Therefore, the recovery of flue gas waste heat as a heat source for station heating can only recover a small part of the waste heat, and the waste heat recovery rate is not high. Utility Model Content

[0004] The main purpose of the utility model is to provide a compressor station waste heat cascade recovery and utilization system, so as to at least solve the problem of low waste heat recovery rate of the compressor station in the prior art.

[0005] In order to achieve the above-mentioned purpose, the utility model provides a compressor station waste heat cascade recovery and utilization system, including: a compressor station engine group, the compressor station engine group is used to burn natural gas to provide gas transmission power to the natural gas pipeline; a waste heat boiler, connected to the compressor station engine group, the waste heat boiler receives the flue gas waste heat generated by the compressor station engine group burning natural gas to generate water vapor; a steam generator set, connected to the waste heat boiler, the steam generator set receives the water vapor generated by the waste heat boiler to generate electricity; an air preheater, connected to the compressor station engine group and the waste heat boiler, the air preheater The device receives the waste heat of the flue gas from the waste heat boiler, preheats the external cold air and then transmits it to the compressor station engine unit; the phase change flue gas processor and the heat pump unit, the phase change flue gas processor is connected to the air preheater and the heat pump unit, the phase change flue gas processor receives the waste heat of the flue gas from the air preheater, exchanges heat with the circulating water of the heat pump unit, and directly discharges the remaining waste heat of the flue gas; the heat pump unit receives the heat after the heat exchange of the circulating water to supply heat to the heating equipment; among them, the compressor station engine unit mixes the hot air preheated by the air preheater with natural gas for combustion to provide gas transmission power to the natural gas pipeline.

[0006] Furthermore, an air heat exchange pipe is provided in the air preheater, and the air heat exchange pipe has a cold air inlet and a hot air outlet; wherein, the cold air inlet is directly connected to the external atmosphere to receive external cold air, and the air heat exchange pipe exchanges heat with the flue gas waste heat of the waste heat boiler to preheat the cold air; the hot air outlet is connected to the compressor station engine unit to deliver the preheated hot air to the compressor station engine unit.

[0007] Furthermore, a waste hot water circulation pipe and a heating water circulation pipe are arranged in the heat pump unit, the phase change flue gas processor is connected to the waste hot water circulation pipe, and the heating water circulation pipe is connected to the heating equipment; wherein, the phase change flue gas processor receives the waste heat of the flue gas from the air preheater to heat the circulating water in the waste hot water circulation pipe and exchanges heat with the circulating water in the heating water circulation pipe; the heating water circulation pipe transports the circulating water after heat exchange to the heating equipment for heating.

[0008] The utility model discloses a gas compressor station waste heat cascade recovery and utilization system, which includes a gas compressor station engine unit, a waste heat boiler, a steam generator unit, an air preheater, a phase change flue gas processor and a heat pump unit. The gas compressor station engine unit burns the natural gas in the station to generate power, thereby providing gas transmission pressure to the natural gas pipeline; the waste heat boiler is connected to the gas compressor station engine unit, and receives the waste heat of the flue gas generated by the combustion of natural gas by the gas compressor station engine unit to generate water vapor; the steam generator unit is connected to the waste heat boiler, and receives the water vapor generated by the waste heat boiler to generate electricity; the air preheater is connected to the gas compressor station engine unit, and receives the water vapor generated by the waste heat boiler to generate electricity. The station engine unit and the waste heat boiler are connected. The air preheater receives the flue gas waste heat from the waste heat boiler to preheat the external cold air and then transmits it to the compressor station engine unit. The compressor station engine unit mixes the hot air preheated by the air preheater with natural gas for combustion, thereby effectively improving the combustion efficiency of natural gas; the phase change flue gas processor is connected to the air preheater and the heat pump unit. The phase change flue gas processor receives the flue gas waste heat from the air preheater and exchanges heat with the circulating water of the heat pump unit and directly discharges the remaining flue gas waste heat; the heat pump unit receives the heat after the circulating water heat exchange to supply heat to the heating equipment. This scheme uses waste heat boilers and steam generator sets, air preheaters, phase change flue gas processors and heat pump units to achieve the cascade utilization of medium and high temperature flue gas waste heat for power generation, medium temperature flue gas for combustion air preheating, and low temperature flue gas for heating, avoiding direct discharge of flue gas waste heat, reducing station electricity and fuel gas consumption, improving energy utilization efficiency, and also reducing the emission of pollutants such as nitrogen oxides. The problem of low waste heat recovery rate of the compressor station in the prior art is solved. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] The drawings constituting part of the present application are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation on the present invention. In the drawings:

[0010] Figure 1 It is a structural schematic diagram of a compressor station waste heat cascade recovery and utilization system that can be selected according to an embodiment of the utility model.

[0011] The above drawings include the following reference numerals:

[0012] 10. Compressor station engine unit; 20. Waste heat boiler; 30. Steam generator unit; 40. Air preheater; 50. Phase change flue gas treatment unit; 60. Heat pump unit. DETAILED DESCRIPTION

[0013] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present utility model will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0014] The utility model technical scheme of the compressor station waste heat cascade recovery and utilization system, such as Figure 1 As shown, it includes a compressor station engine unit 10, a waste heat boiler 20, a steam generator unit 30, an air preheater 40, a phase change flue gas processor 50 and a heat pump unit 60. The compressor station engine unit 10 burns the natural gas in the station to generate power so as to provide gas transmission pressure to the natural gas pipeline; the waste heat boiler 20 is connected to the compressor station engine unit 10, and receives the waste heat of the flue gas generated by the compressor station engine unit 10 burning the natural gas to generate water vapor; the steam generator unit 30 is connected to the waste heat boiler 20, and the steam generator unit 30 receives the water vapor generated by the waste heat boiler 20 to generate electricity; the air preheater 40 is connected to the compressor station engine unit 10 and the waste heat boiler 20. The heat boilers 20 are all connected, the air preheater 40 receives the waste heat of the flue gas from the waste heat boiler 20, preheats the external cold air, and then transmits it to the compressor station engine unit 10, and the compressor station engine unit 10 mixes the hot air preheated by the air preheater 40 with natural gas for combustion, thereby effectively improving the combustion efficiency of the natural gas; the phase change flue gas processor 50 is connected to both the air preheater 40 and the heat pump unit 60, the phase change flue gas processor 50 receives the waste heat of the flue gas from the air preheater 40, exchanges heat with the circulating water of the heat pump unit 60, and directly discharges the remaining waste heat of the flue gas; the heat pump unit 60 receives the heat after heat exchange with the circulating water to supply heat to the heating equipment. This solution uses the waste heat boiler 20, steam generator set 30, air preheater 40, phase change flue gas processor 50 and heat pump unit 60 to realize the cascade utilization of medium and high temperature flue gas waste heat for power generation, medium temperature flue gas for combustion air preheating, and low temperature flue gas for heating, avoiding direct emission of flue gas waste heat, reducing station electricity and fuel gas consumption, improving energy utilization efficiency, and also reducing the emission of pollutants such as nitrogen oxides. It solves the problem of low waste heat recovery rate of medium pressure gas station in the prior art.

[0015] During specific implementation, the compressor station engine unit 10 burns the station natural gas to provide power for increasing the natural gas pressure, and at the same time generates high-temperature flue gas of 550°C. The waste heat boiler 20 absorbs the waste heat of the 550°C medium-temperature flue gas and converts it into 180°C medium-temperature flue gas, and provides sufficient steam as power for the steam generator unit 30; the steam generator unit 30 uses the steam provided by the waste heat boiler 20 as power to generate electricity, providing the station with self-use electricity; the air preheater 40 is used to absorb the waste heat of the 180°C medium-temperature flue gas and convert it into 60°C low-temperature flue gas. The absorbed flue gas waste heat is used to preheat the combustion air of the compressor station engine unit 10. By preheating the air, the consumption of natural gas can be reduced. The phase-change flue gas processor 50 absorbs the waste heat of the low-temperature flue gas at 60°C and converts it into flue gas at room temperature of 20°C. The absorbed waste heat of the flue gas is used to provide a low-quality heat source for the heat pump unit 60; the heat pump unit 60 provides low-temperature chilled water for the phase-change flue gas processor 50 to absorb the waste heat of the low-temperature flue gas. The sensible heat in the flue gas and the latent heat of condensation of water vapor are fully recovered and then discharged into the air. The waste heat of the flue gas absorbed by the chilled water is upgraded by the heat pump unit 60 and used as a heating heat source for the site.

[0016] Furthermore, an air heat exchange pipe is provided in the air preheater 40, and the air heat exchange pipe has a cold air inlet and a hot air outlet; the cold air inlet is directly connected to the external atmosphere to receive external cold air, and the air heat exchange pipe exchanges heat with the flue gas waste heat of the waste heat boiler 20 to preheat the cold air; the hot air outlet is connected to the compressor station engine unit 10 to transport the preheated hot air to the compressor station engine unit 10 to mix with natural gas for combustion. Since the cold air is preheated, the combustion efficiency of the natural gas is effectively improved and the consumption of natural gas is reduced.

[0017] Furthermore, a waste hot water circulation pipeline is provided on the evaporator side of the heat pump unit 60, and a heating water circulation pipeline is provided on the condensation side of the heat pump unit 60. The phase change flue gas processor 50 is connected to the waste hot water circulation pipeline, and the heating water circulation pipeline is connected to the heating equipment; the phase change flue gas processor 50 receives the 60°C low-temperature flue gas waste heat from the air preheater 40 to heat the circulating water in the waste hot water circulation pipeline and exchange heat with the circulating water in the heating water circulation pipeline; the heating water circulation pipeline transports the circulating water after heat exchange to the heating equipment for heating. The phase change flue gas processor 50 uses anti-corrosion materials to solve the problem of flue gas condensation corrosion. The chilled water on the evaporator side of the heat pump unit 60 provides a low-temperature heat absorption medium for the phase change flue gas processor 50 to absorb the low-temperature flue gas waste heat, and at the same time, the condensation side of the heat pump unit 60 provides a heating heat source for the heating equipment.

[0018] Compared with the prior art, the beneficial effects of the utility model are:

[0019] 1. The utility model utilizes the waste heat boiler 20, the air preheater 40, and the phase change flue gas processor 50 in series to realize the step-by-step recovery and utilization of flue gas waste heat. The flue gas temperature can be recovered to about 20°C before being discharged, thereby maximizing the utilization of the sensible heat of the flue gas and the latent heat of water vapor in the flue gas.

[0020] 2. The phase-change flue gas processor 50 of the present invention adopts anti-corrosion materials to solve the problem of flue gas condensation corrosion.

[0021] 3. The utility model adopts a waste heat boiler 20 and a steam generator set 30 to convert high-temperature waste heat into high-quality electric energy for the station to use, thus solving the problem of waste heat redundancy in natural gas stations.

[0022] In short, compared with the conventional waste heat utilization technology of the compressor station, the utility model can fully utilize the waste heat of the flue gas and reduce it to 20°C, thereby improving the utilization rate of the sensible heat of the flue gas and the latent heat of condensation of water vapor, and significantly improving the energy utilization efficiency; at the same time, the utility model converts the waste heat of the flue gas into electrical energy, combustion air heat energy and heating heat energy according to the different temperature grades of the waste heat, thereby solving the problem of redundant waste heat in the compressor station.

[0023] The above description is only the preferred embodiment of the utility model, and is not intended to limit the utility model. For those skilled in the art, the utility model can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the utility model shall be included in the protection scope of the utility model.

Claims

1. A compressor station waste heat cascade recovery and utilization system, characterized in that: include: A compressor station engine unit (10), the compressor station engine unit (10) being used to burn natural gas to provide gas transmission power to a natural gas pipeline; A waste heat boiler (20) is connected to the compressor station engine unit (10), and the waste heat boiler (20) receives waste heat from flue gas generated by combustion of natural gas by the compressor station engine unit (10) to generate water vapor; A steam generator set (30) is connected to the waste heat boiler (20), and the steam generator set (30) receives the steam generated by the waste heat boiler (20) to generate electricity; an air preheater (40) connected to the compressor station engine unit (10) and the waste heat boiler (20), wherein the air preheater (40) receives waste heat from flue gas of the waste heat boiler (20) to preheat external cold air and then transmits the air to the compressor station engine unit (10); A phase-change flue gas processor (50) and a heat pump unit (60), wherein the phase-change flue gas processor (50) is connected to both the air preheater (40) and the heat pump unit (60); the phase-change flue gas processor (50) receives flue gas waste heat from the air preheater (40) and exchanges heat with circulating water of the heat pump unit (60), and directly discharges the remaining flue gas waste heat; the heat pump unit (60) receives heat from the circulating water after heat exchange to supply heat to the heating equipment; The compressor station engine unit (10) mixes the hot air preheated by the air preheater (40) with natural gas for combustion to provide gas transmission power to the natural gas pipeline.

2. The compressor station waste heat cascade recovery and utilization system according to claim 1 is characterized in that: An air heat exchange pipe is arranged in the air preheater (40), and the air heat exchange pipe has a cold air inlet and a hot air outlet; The cold air inlet is directly connected to the external atmosphere to receive external cold air, the air heat exchange pipe exchanges heat with the flue gas waste heat of the waste heat boiler (20) to preheat the cold air; and the hot air outlet is connected to the compressor station engine unit (10) to transport the preheated hot air to the compressor station engine unit (10).

3. The compressor station waste heat cascade recovery and utilization system according to claim 1 is characterized in that: A waste water circulation pipeline and a heating water circulation pipeline are arranged in the heat pump unit (60), the phase change flue gas processor (50) is connected to the waste water circulation pipeline, and the heating water circulation pipeline is connected to the heating equipment; The phase change flue gas processor (50) receives the waste heat of the flue gas from the air preheater (40) to heat the circulating water in the waste water circulation pipe and exchanges heat with the circulating water in the heating water circulation pipe; the heating water circulation pipe transports the circulating water after heat exchange to the heating equipment for heating.

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