A device and method for quickly adjusting load using a long-distance heating pipe network

Abstract

The present invention provides a device and method for rapid load regulation using a long-distance heating pipeline network, comprising a heat source, an extraction steam heat exchange unit, a long-distance heating pipeline network and a heat user unit, wherein: the exhaust steam outlet of the heat source is connected to the air inlet of the extraction steam heat exchange unit, the return water inlet of the extraction steam heat exchange unit is connected to the return water outlet of the long-distance heating pipeline network, and the return water inlet of the long-distance heating pipeline network is connected to the return water outlet of the heat user unit; the water supply outlet of the extraction steam heat exchange unit is connected to the water supply inlet of the heat user unit through the long-distance heating pipeline network; the present invention ensures that the steam pressure and temperature of the load on the other side remain unchanged during the process of adjusting the electric load or the thermal load, and has low control requirements for the boiler, steam flow, extraction steam valve and steam turbine connecting valve; in addition to realizing the regulation of the electric load or the thermal load by controlling the boiler combustion and steam parameters, the present invention also adjusts the electric load or the thermal load of the unit by means of extraction steam regulation on the heating side, thereby shortening the load regulation time.

Description

Technical Field

[0001] The present invention belongs to the field of heating, and in particular relates to a device and method for quickly adjusting loads by using a long-distance heating pipe network. Background Art

[0002] At present, the heating capacity of centralized heating sources in a large number of cities in northern my country is limited and cannot meet the heating needs of cities. The heating gap is large. Enterprises and institutions in urban areas use their own boilers for production and heating. The heating method is decentralized boiler room heating, and the fuel is mainly coal, which causes energy waste and air pollution. In accordance with the spirit of the state to dismantle and integrate decentralized small coal-fired boiler rooms, relevant power plants must adopt practical technical means to improve the heating capacity of the units and complete the task of dismantling and integrating small coal-fired boiler rooms in the heating area.

[0003] Long-distance heating has the energy-saving effect of reducing urban environmental pollution and taking into account the comprehensive utilization of energy. Some large thermal power units need to achieve centralized heating through long-distance heating because their sites are far away from the urban area. Long-distance heating also faces the joint adjustment of thermal load and electric load in traditional cogeneration units. In traditional cogeneration units, when receiving a heat load or electric load adjustment instruction, the steam pressure and temperature of the load on the other side are generally kept unchanged, and the changes in electric load or heat load are adjusted by means of boilers and main steam flow. Existing long-distance heating projects in operation and long-distance heating projects under construction also achieve cogeneration of heat and power through the above method.

[0004] However, the above adjustment scheme has the following disadvantages:

[0005] 1. In the above regulation scheme, it is necessary to ensure that the steam pressure and temperature of the load on the other side remain unchanged as much as possible during the adjustment of the electrical load or thermal load, and the control requirements for the boiler, steam flow, extraction valve and steam turbine connecting valve are relatively high.

[0006] 2. The above regulation scheme mainly realizes the regulation of electric load or thermal load by controlling boiler combustion and steam parameters, and the regulation speed is relatively slow.

[0007] 3. The above regulation scheme results in the thermal power units still relying mainly on the adjustment of boilers to achieve peak load and frequency regulation, and the flexibility of the thermal power units themselves is not greatly improved. Summary of the invention

[0008] The purpose of the present invention is to provide a device and method for quickly adjusting load by using a long-distance heating pipe network, thereby solving the above-mentioned deficiencies in the prior art.

[0009] In order to achieve the above object, the technical solution adopted by the present invention is:

[0010] The present invention provides a device for rapid load regulation using a long-distance heating pipeline network, comprising a heat source, an extraction steam heat exchange unit, a long-distance heating pipeline network and a heat user unit, wherein: the exhaust steam outlet of the heat source is connected to the air inlet of the extraction steam heat exchange unit, the return water inlet of the extraction steam heat exchange unit is connected to the return water outlet of the long-distance heating pipeline network, and the return water inlet of the long-distance heating pipeline network is connected to the return water outlet of the heat user unit; the water supply outlet of the extraction steam heat exchange unit is connected to the water supply inlet of the heat user unit through the long-distance heating pipeline network.

[0011] Preferably, the heat source comprises a first thermoelectric unit and a second thermoelectric unit, wherein exhaust ports of the first thermoelectric unit and the second thermoelectric unit are both connected to a steam inlet of the steam extraction heat exchange unit.

[0012] Preferably, the first thermal power unit includes a first condenser, a first boiler and a steam turbine, wherein the water outlet of the first condenser is connected to the water inlet of the first boiler through a first feed water pump, the superheated steam outlet of the first boiler is connected to the steam inlet of the steam turbine, and the exhaust port of the steam turbine is divided into two paths, one path is connected to the steam extraction heat exchange unit; the other path is connected to the air inlet of the first condenser.

[0013] Preferably, a first steam extraction regulating valve is provided between the steam exhaust port of the steam turbine and the steam extraction heat exchange unit;

[0014] A connecting pipe regulating valve is arranged between the exhaust port of the steam turbine and the air inlet of the first condenser.

[0015] Preferably, the second thermal power unit includes a second condenser, a second boiler, a high-pressure steam turbine and a low-pressure steam turbine, wherein the water outlet of the second condenser is connected to the water inlet of the second boiler through a second feed water pump, the superheated steam outlet of the second boiler is connected to the steam inlet of the high-pressure steam turbine, the exhaust outlet of the high-pressure steam turbine is divided into two paths, one path is connected to the steam inlet of the low-pressure steam turbine, and the exhaust outlet on the low-pressure steam turbine is connected to the air inlet of the second condenser; the other path is the steam inlet of the steam extraction heat exchange unit.

[0016] Preferably, a high-low pressure connecting pipe regulating valve is provided between the steam exhaust port of the high-pressure steam turbine and the steam inlet of the low-pressure steam turbine;

[0017] A second steam extraction regulating valve is arranged between the steam exhaust port of the high-pressure steam turbine and the steam extraction heat exchange unit.

[0018] Preferably, the extraction steam heat exchange unit includes a first basic heater, a second basic heater and a peak heater, wherein the return water inlets of the first basic heater and the second basic heater are both connected to the return water outlet of the long-distance heating pipeline network; the steam inlets of the first basic heater and the second basic heater are both connected to the exhaust outlet of the first thermal power unit of the heat source; the return water outlets of the first basic heater and the second basic heater are both connected to the return water inlet of the peak heater, and the return water outlet of the peak heater is connected to the water supply inlet of the long-distance heating pipeline network.

[0019] Preferably, the long-distance heating pipeline network includes a pressure isolating station, wherein the return water inlet of the pressure isolating station is connected to the return water outlet of the heat user unit; the return water outlet of the pressure isolating station is connected to the return water inlet of the steam extraction heat exchange unit through a return water pump; the water supply inlet of the pressure isolating station is connected to the water supply outlet of the steam extraction heat exchange unit through a water supply pump; the water supply outlet of the pressure isolating station is connected to the water supply inlet of the heat user unit.

[0020] Preferably, a bypass is provided between the water supply inlet and the return water outlet of the pressure isolation station.

[0021] A method for rapid load regulation using a long-distance heating pipe network comprises the following steps:

[0022] When the electrical load needs to be increased and the thermal load remains unchanged, the working parameters of the heat source are adjusted to reduce the steam extraction volume of the steam extraction heat exchange unit and, at the same time, increase the return water flow of the long-distance heating pipeline network;

[0023] When the heat load needs to be increased and the electrical load remains unchanged, the work parameters of the heat source are adjusted to increase the steam extraction volume of the steam extraction heat exchange unit and, at the same time, reduce the return water flow of the long-distance heating pipeline network.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] The present invention provides a device and method for rapid load regulation using a long-distance heating pipeline network. When a cogeneration unit used for long-distance heating receives a command to increase or decrease the electric load or the thermal load, on the one hand, the load change is achieved based on the adjustment of conventional boiler combustion and water supply. On the other hand, the long-distance heating pipeline network is used to adjust the valve opening of the steam extraction pipeline or the connecting pipeline while increasing or decreasing the load, thereby assisting in increasing the load regulation speed. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 is a system structure diagram of the present invention;

[0027] Among them, 1, the first condenser 2, the first feed water pump 3, the first boiler 4, the steam turbine 5, the connecting pipe regulating valve 6, the second condenser 7, the second feed water pump 8, the second boiler 9, the high-pressure steam turbine 10, the low-pressure steam turbine 11, the high-and-low-pressure connecting pipe regulating valve 12, the first extraction steam regulating valve 13, the second extraction steam regulating valve 14, the first regulating valve 15, the second regulating valve 16, the first basic heater 17, the second basic heater 18, the peak heater 19, the water supply pump 20, the pressure isolation station 21, the bypass regulating valve 22, the return water pump 23, and the thermal power station. DETAILED DESCRIPTION

[0028] The present invention will be further described in detail below in conjunction with the accompanying drawings.

[0029] The present invention provides a device and method for rapid load regulation using a long-distance heating pipeline network. When a cogeneration unit used for long-distance heating receives a command to increase or decrease the electric load or the thermal load, on the one hand, the load change is achieved based on the adjustment of conventional boiler combustion and water supply. On the other hand, the long-distance heating pipeline network is used to adjust the valve opening of the steam extraction pipeline or the connecting pipeline while increasing or decreasing the load, thereby assisting in increasing the load regulation speed.

[0030] The present invention provides a device for rapid load adjustment using a long-distance heating pipeline network, which mainly includes a heat source, an extraction steam heat exchange unit, a long-distance heating pipeline network and a heat user unit, wherein: the exhaust steam outlet of the heat source is connected to the air inlet of the extraction steam heat exchange unit, the return water inlet of the extraction steam heat exchange unit is connected to the return water outlet of the long-distance heating pipeline network, and the return water inlet of the long-distance heating pipeline network is connected to the return water outlet of the heat user unit; the water supply outlet of the extraction steam heat exchange unit is connected to the water supply inlet of the heat user unit through the long-distance heating pipeline network.

[0031] Specifically: the heat source includes two typical cogeneration units, the first is the first low-pressure cylinder zero-output unit, denoted as the first thermal power unit, the first thermal power unit includes a first condenser 1, a first feedwater pump 2, a first boiler 3, a steam turbine 4, and a first interconnecting pipe regulating valve 5, wherein the water outlet of the first condenser 1 is connected to the water inlet of the first boiler 3 through the first feedwater pump 2, the superheated steam outlet of the first boiler 3 is connected to the steam inlet of the steam turbine 4, the exhaust port of the steam turbine 4 is divided into three paths through the first extraction regulating valve 12, one path is connected to the first basic heater 16 through the first regulating valve 14, and the other path is connected to the second basic heater 17 through the second regulating valve 15; the last path is connected to the air inlet of the first condenser 1 through the first interconnecting pipe regulating valve 5.

[0032] The second type is the second perforated extraction unit, denoted as the second thermal power unit, which includes a second condenser 6, a second feedwater pump 7, a second boiler 8, a high-pressure steam turbine 9, a low-pressure steam turbine 10 and a high-low pressure connecting pipe regulating valve 11, wherein the water outlet of the second condenser 6 is connected to the water inlet of the second boiler 8 through the second feedwater pump 7, the superheated steam outlet of the second boiler 8 is connected to the steam inlet of the high-pressure steam turbine 9, and the exhaust outlet of the high-pressure steam turbine 9 is divided into two paths, one of which is connected to the steam inlet of the low-pressure steam turbine 10 through the high-low pressure connecting pipe regulating valve 11, and the exhaust outlet on the low-pressure steam turbine 10 is connected to the air inlet of the second condenser 6; the other path is connected to the steam inlet of the peak heater 18 through the second extraction regulating valve 13.

[0033] The circulating water outlets on the first basic heater 16 and the second basic heater 17 are both connected to the water inlet of the peak heater 18 , and the water outlet of the peak heater 18 is connected to the pressure isolation station 20 through the water supply pump 19 .

[0034] The return water outlet of the pressure isolation station 20 is connected to the water inlet of the first basic heater 16 and the water inlet of the second basic heater 17 through a return water pump.

[0035] The water supply outlet on the pressure isolation station 20 is connected to a plurality of thermal power stations 23 ; and the return water outlets of the plurality of thermal power stations 23 are connected to the return water inlet on the pressure isolation station 20 .

[0036] A bypass is provided between the water outlet of the water supply pump 19 and the return water outlet of the pressure isolation station 20 , and a bypass regulating valve 21 is provided on the bypass.

[0037] Working process of the present invention:

[0038] The exhaust steam of the steam turbine 4 in the first thermal power unit serves as a heat source for the first thermal power unit, and enters the first basic heater 16 and the second basic heater 17 through the first extraction regulating valve 12, wherein the first basic heater 16 and the second basic heater 17 are respectively provided with a first regulating valve 14 and a second regulating valve 15 in front of them for regulating the amount of steam entering the two basic heaters.

[0039] The exhaust steam of the high-pressure steam turbine 9 in the second thermal power unit is used as a heat source for heating the second thermal power unit and enters the peak heater 18 through the second steam extraction regulating valve 13 .

[0040] The circulating water of the long-distance heat transmission network first enters the first basic heater 16 and the second basic heater 17 through the return pump 22. After the temperature is initially increased, it enters the peak heater 18, and the temperature is further increased to meet the water supply temperature requirements of the long-distance pipeline network. Then, it enters the pressure isolation station 20 in the urban area through the water supply pump 19. A bypass pipe is arranged near the pressure isolation station, and a bypass regulating valve 21 is arranged on it for adjusting the amount of long-distance circulating water passing through the pressure isolation station 20.

[0041] After the circulating water of the urban primary network absorbs the heat of the circulating water of the long-distance pipeline network in the pressure isolation station, it enters the urban thermal power station 23 for urban heating.

[0042] For the first station, when the extraction parameters are constant, the steam extraction of the first thermal power unit, the steam extraction of the second thermal power unit and the long-distance heat network circulating water flow rate determine the final outlet temperature of the circulating water at the peak heater 18; the long-distance heat network circulating water flow rate determines the time for the long-distance heat network circulating water to reach the pressure isolation station 20 from the outlet of the peak heater 18. The greater the circulating water flow rate, the shorter the time required, and vice versa. Generally speaking, the temperature change of the circulating water at the first station of the heat network will take about 10 hours to be reflected in the pressure isolation station 20; the long-distance heat network circulating water flow rate and the outlet temperature of the circulating water flow rate at the peak heater 18 determine the heat storage capacity of the heat network; the heat absorbed by the urban primary network circulating water at the pressure isolation station 20 is mainly related to the temperature and flow of the long-distance heat network circulating water. Therefore, the steam extraction of the first thermal power unit, the steam extraction of the second thermal power unit and the long-distance heat network circulating water flow rate determine the heat absorbed by the urban primary network circulating water at the pressure isolation station 20 at a certain moment. When the electrical load of the unit changes, the load change can be achieved not only by adjusting the boiler, but also by adjusting the steam extraction volume of the first thermal power unit, the steam extraction volume of the second thermal power unit, and the circulating water flow rate of the long-distance heat transmission network, so as to further adjust the electrical load while ensuring that the urban primary network absorbs a certain amount of heat.

[0043] The following is a typical load regulation process:

[0044] When the unit is providing heat and power stably, and the heat load on the urban side does not change, the power grid requires the power plant to increase the power load. At this time, on the one hand, the combustion of the first boiler 3 and the second boiler 8 is enhanced, and the water supply of the first feedwater pump 2 and the second feedwater pump 7 is increased. On the other hand, the opening of the first regulating valve 14 and the second steam extraction regulating valve 13 is reduced, and the opening of the high-low pressure connecting valve 11 is increased, so as to quickly improve the working capacity of the steam turbine 4 and the high-pressure steam turbine 9 and the low-pressure steam turbine 10, and realize a rapid increase in the power load;

[0045] When the circulating water flow rate of the long-distance heat transmission network remains unchanged, the above operation will also cause the circulating water outlet temperature of the peak heater 18 to decrease. Taking into account the hysteresis of the long-distance heat transmission network, the circulating water of the long-distance heat transmission network with the temperature reduced will reach the pressure isolation station 20 after about 10 hours. At this time, the circulating water flow rate is further increased to enhance the heat exchange capacity in the pressure isolation station 20 to compensate for the decrease in heat exchange caused by the temperature reduction, until the circulating water outlet temperature reaches the normal design temperature, and then the circulating water flow rate is reduced to the normal design level.

[0046] Therefore, through the above-mentioned regulation scheme, it is possible to utilize the long-distance pipeline network's long-time lag characteristics and heat storage capacity to enable the unit to quickly respond to the regulation requirements of the electric load.

[0047] The beneficial effects of the present invention are:

[0048] 1. In the process of adjusting the electrical load or thermal load, the unit load can be quickly adjusted by further adjusting the heating steam extraction valve and the turbine connecting valve.

[0049] 2. By changing the circulating water flow rate of the long-distance pipeline network in stages, the coupling of the changes in electric load and thermal load on different time scales can be achieved, thereby realizing the flexible adjustment of the electric load and thermal load of the cogeneration unit.

[0050] 3. By utilizing the long-distance pipeline network’s long-time lag characteristics and heat storage capacity, the unit-side heat source adjustment is first reflected in the system characteristics of the long-distance pipeline network, thereby avoiding direct impact on the heat load side.

[0051] This solution does not require that the steam pressure and temperature of the load on the other side remain unchanged during the adjustment of the electrical load or thermal load, and has relatively low control requirements for the boiler, steam flow, extraction valve and steam turbine connecting valve.

[0052] In addition to adjusting the electrical load or thermal load by controlling boiler combustion and steam parameters, this solution also adjusts the electrical load or thermal load of the unit by adjusting the steam extraction on the heating side, thus shortening the load adjustment time.

[0053] This solution further enhances the flexibility of the thermal power units themselves.

Claims

1. A device for rapid load regulation using a long-distance heating network, characterized in that: It includes a heat source, a steam extraction heat exchange unit, a long-distance heating pipeline network and a heat user unit, wherein: the exhaust steam outlet of the heat source is connected to the air inlet of the steam extraction heat exchange unit, the return water inlet of the steam extraction heat exchange unit is connected to the return water outlet of the long-distance heating pipeline network, and the return water inlet of the long-distance heating pipeline network is connected to the return water outlet of the heat user unit; the water supply outlet of the steam extraction heat exchange unit is connected to the water supply inlet of the heat user unit through the long-distance heating pipeline network; the heat source includes a first thermal power unit and a second thermal power unit, wherein the exhaust steam outlets of the first thermal power unit and the second thermal power unit are both connected to the steam inlet of the steam extraction heat exchange unit; The first thermal power unit comprises a first condenser (1), a first boiler (3) and a steam turbine (4), wherein the water outlet of the first condenser (1) is connected to the water inlet of the first boiler (3) via a first feedwater pump (2), the superheated steam outlet of the first boiler (3) is connected to the steam inlet of the steam turbine (4), and the exhaust port of the steam turbine (4) is divided into two paths, one of which is connected to the steam extraction heat exchange unit; and the other is connected to the air inlet of the first condenser (1); A first steam extraction regulating valve (12) is provided between the steam exhaust port of the steam turbine (4) and the steam extraction heat exchange unit; A connecting pipe regulating valve (5) is provided between the exhaust port of the steam turbine (4) and the air inlet of the first condenser (1); The second thermal power unit comprises a second condenser (6), a second boiler (8), a high-pressure steam turbine (9) and a low-pressure steam turbine (10), wherein the water outlet of the second condenser (6) is connected to the water inlet of the second boiler (8) via a second feedwater pump (7), the superheated steam outlet of the second boiler (8) is connected to the steam inlet of the high-pressure steam turbine (9), the exhaust steam outlet of the high-pressure steam turbine (9) is divided into two paths, one path is connected to the steam inlet of the low-pressure steam turbine (10), and the exhaust steam outlet on the low-pressure steam turbine (10) is connected to the air inlet of the second condenser (6); the other path is connected to the steam inlet of the steam extraction heat exchange unit; A high- and low-pressure connecting pipe regulating valve (11) is provided between the steam exhaust port of the high-pressure steam turbine (9) and the steam inlet of the low-pressure steam turbine; A second steam extraction regulating valve (13) is provided between the exhaust port of the high-pressure steam turbine (9) and the steam extraction heat exchange unit; The extraction heat exchange unit comprises a first basic heater (16), a second basic heater (17) and a peak heater (18), wherein the return water inlets of the first basic heater (16) and the second basic heater (17) are both connected to the return water outlet of the long-distance heating pipeline network; the steam inlets of the first basic heater (16) and the second basic heater (17) are both connected to the exhaust steam outlet of the first thermal power unit of the heat source; the return water outlets of the first basic heater (16) and the second basic heater (17) are both connected to the return water inlet of the peak heater (18), and the return water outlet of the peak heater (18) is connected to the water supply inlet of the long-distance heating pipeline network; The long-distance heat supply pipeline network comprises a pressure isolating station (20), wherein the return water inlet of the pressure isolating station (20) is connected to the return water outlet of the heat user unit; the return water outlet of the pressure isolating station (20) is connected to the return water inlet of the steam extraction heat exchange unit via a return water pump (22); the water supply inlet of the pressure isolating station (20) is connected to the water supply outlet of the steam extraction heat exchange unit via a water supply pump (19); and the water supply outlet of the pressure isolating station (20) is connected to the water supply inlet of the heat user unit.

2. The device for rapid load regulation using a long-distance heating network according to claim 1 is characterized in that: A bypass is provided between the water supply inlet and the return water outlet of the pressure isolation station (20).

3. A method for rapid load regulation using a long-distance heating network, characterized in that: The device according to claim 1 or 2 comprises the following steps: When the electrical load needs to be increased and the thermal load remains unchanged, the working parameters of the heat source are adjusted to reduce the steam extraction volume of the steam extraction heat exchange unit and, at the same time, increase the return water flow of the long-distance heating pipeline network; When the heat load needs to be increased and the electrical load remains unchanged, the work parameters of the heat source are adjusted to increase the steam extraction volume of the steam extraction heat exchange unit and, at the same time, reduce the return water flow of the long-distance heating pipeline network.

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