A multi-source complementary heating system and method for cascaded energy utilization

Abstract

The present invention discloses a multi-source complementary heating system for cascaded energy utilization, comprising a coal-fired steam boiler, a steam turbine, an exhaust steam waste heat recovery mechanism, a primary flue gas waste heat recovery mechanism, a secondary flue gas waste heat recovery mechanism, a sewage waste heat recovery mechanism, a proximal network circulation mechanism, a distal primary network circulation mechanism, a distal secondary network circulation mechanism and a gas boiler, and discloses a multi-source complementary heating method for cascaded energy utilization. The multi-source complementary heating system for cascaded energy utilization can effectively reduce heat loss in the heat transmission process, reduce equipment investment, and achieve the ideal effect of optimal energy and optimal use; energy cascade utilization is achieved on the basis of ensuring that the indoor temperature of heat users is appropriate, thereby reducing pollution to the environment.

Description

Technical Field

[0001] The present invention relates to the technical field of new energy centralized heating, and more specifically to a multi-source complementary heating system and method for cascaded energy utilization. Background Art

[0002] At present, most centralized heating systems use only a single heat source, which is limited by many factors. Once a failure occurs and there is no alternative heat source, the heating system will be paralyzed, and the output safety and stability will be poor. In addition, the traditional heating system uses coal as the main fuel, and coal combustion will bring serious pollution problems and cause irreversible impacts on the environment. In addition, the existing heating system has a low energy utilization rate and is prone to waste of resources.

[0003] To solve the above problems, clean energy such as wind energy and solar energy can be reasonably introduced into the field of centralized heating to form a multi-source complementary heating form. However, the heating system equipment formed in this way requires large investment, and it is difficult to achieve a unified outlet water temperature for heating from multiple heat sources, making it difficult to ensure that the water supply temperature of the heating network is stable and meets the heating demand; moreover, the formed heating system simply connects several heating methods together, with low energy utilization, which still results in low energy utilization, waste of resources, and the environmental pollution problem cannot be significantly improved.

[0004] Therefore, how to build an efficient, clean, and energy-efficient multi-source complementary heating system is an urgent problem that technicians in this field need to solve. Summary of the invention

[0005] In view of this, the present invention provides a multi-source complementary heating system and method for cascaded energy utilization, which can effectively reduce heat loss in the heat transmission process, reduce equipment investment, and achieve the ideal effect of optimal energy utilization; it realizes cascaded energy utilization on the basis of ensuring that the indoor temperature of heat users is suitable, thereby reducing pollution to the environment.

[0006] In order to achieve the above object, the present invention adopts the following technical solution:

[0007] A multi-source complementary heating system with cascaded energy utilization, comprising a coal-fired steam boiler, a steam turbine, an exhaust steam waste heat recovery mechanism, a primary flue gas waste heat recovery mechanism, a secondary flue gas waste heat recovery mechanism, a sewage waste heat recovery mechanism, a proximal network circulation mechanism, a distal primary network circulation mechanism, a distal secondary network circulation mechanism and a gas boiler;

[0008] The high-temperature steam outlet of the coal-fired steam boiler is connected to the steam turbine, and the flue gas outlet is sequentially connected to the primary flue gas waste heat recovery mechanism and the secondary flue gas waste heat recovery mechanism through the flue;

[0009] The steam turbine is driven and connected to the secondary flue gas waste heat recovery mechanism;

[0010] The exhaust steam waste heat recovery mechanism is connected to the steam turbine upstream and the coal-fired steam boiler downstream; at the same time, the exhaust steam waste heat recovery mechanism is connected to the secondary flue gas waste heat recovery mechanism and the sewage waste heat recovery mechanism upstream, and is connected to the remote primary network circulation mechanism downstream; and the exhaust steam waste heat recovery mechanism is also connected to the primary flue gas waste heat recovery mechanism upstream through the first gate valve, the first booster pump and the first supplementary heat pipe;

[0011] The upstream of the primary flue gas waste heat recovery mechanism is connected to the proximal network circulation mechanism, and the upstream is also connected to the distal primary network circulation mechanism through the first flow regulating valve and the first heat supplement return pipe, and the downstream is connected to the proximal network circulation mechanism;

[0012] The secondary flue gas waste heat recovery mechanism and the sewage waste heat recovery mechanism are connected to the distal primary network circulation mechanism upstream, and are connected to the proximal network circulation mechanism downstream through a second flow regulating valve and a second heat supplement pipe;

[0013] The downstream of the proximal network circulation mechanism is connected to the distal primary network circulation mechanism through a second gate valve, a second booster pump and a second heat supplement return pipe;

[0014] The remote primary network circulation mechanism is connected to the remote secondary network circulation mechanism to form a closed loop;

[0015] The gas boiler is connected to the remote primary network circulation mechanism to form a closed loop.

[0016] The beneficial effects of the above-mentioned preferred technical scheme are as follows: a multi-source complementary heating system with cascaded energy utilization disclosed in the present invention, on the one hand, utilizes a primary flue gas waste heat recovery mechanism to heat the proximal network return water to obtain proximal network water supply that meets the temperature requirements, thereby providing heat to proximal heat users; on the other hand, utilizes a secondary flue gas waste heat recovery mechanism and a sewage waste heat recovery mechanism to preliminarily heat the circulating return water of the remote primary network, and then utilizes an exhaust steam waste heat recovery mechanism to further heat it, so that the obtained remote primary network water supply can meet the temperature requirements, thereby providing heat to remote heat users. Among them, according to the different losses in the heating process between the near-end heat users and the far-end heat users, the sub-network operation mode is adopted, which effectively reduces the heat loss in the heat transmission process, reduces the equipment investment, and achieves the ideal effect of optimal use of energy; and the cascade utilizes the waste heat and exhaust steam generated in the production process of the heating system to reduce energy waste; in addition, the sewage waste heat recovery mechanism is used to extract low-grade heat from the sewage to supplement the heat to the heating system, reducing the demand for heat extraction through coal combustion, thereby reducing the pollutant emissions of coal-fired boilers; at the same time, the secondary flue gas waste heat recovery mechanism and the sewage waste heat recovery mechanism are connected in parallel. If a device fails, it will not affect the overall heating effect, which improves the stability of the overall heating system. In addition, the two heat networks are connected by heat supplement pipes and heat supplement return pipes to supplement each other's heat under different loads; at the same time, a gas boiler that can be quickly started and stopped is set to supplement heat in extremely cold weather to ensure that the linkage coupling of the entire heating system is improved to the greatest extent.

[0017] Preferably, the exhaust steam waste heat recovery mechanism includes a steam pipe, a steam-water heat exchanger and a condensed water pipe;

[0018] The steam pipe connects the steam outlet of the steam turbine and the hot water inlet pipe of the steam-water heat exchanger;

[0019] The cold water outlet pipe of the steam-water heat exchanger is connected to the return pipe of the coal-fired steam boiler through the condensing water pipe, the cold water inlet pipe of the steam-water heat exchanger is respectively connected to the secondary flue gas waste heat recovery mechanism and the sewage waste heat recovery mechanism, and the cold water inlet pipe of the steam-water heat exchanger is also connected to the primary flue gas waste heat recovery mechanism through the first gate valve, the first booster pump and the first heat supplement pipe, and the hot water outlet pipe of the steam-water heat exchanger is connected to the remote primary network circulation mechanism.

[0020] The beneficial effect of the above-mentioned preferred technical solution is that the present invention can recover the waste heat of the low-temperature exhaust steam generated by the steam turbine through the cooperation of the steam pipe, the steam-water heat exchanger and the condensate pipe, and further heat the remote primary network return water that has been initially heated, thereby obtaining the remote primary network water supply that meets the temperature supply requirements.

[0021] Preferably, the primary flue gas waste heat recovery mechanism comprises a primary desulfurization water bed, a primary desulfurization slurry circulation pump and a primary heat exchanger;

[0022] The flue gas inlet of the primary desulfurization water bed is connected to the flue gas outlet of the coal-fired steam boiler through the flue, the flue gas outlet of the primary desulfurization water bed is connected to the secondary flue gas waste heat recovery mechanism through the flue, the desulfurization slurry water outlet pipe of the primary desulfurization water bed is connected to the hot water inlet pipe of the primary heat exchanger through the primary desulfurization slurry circulation pump, and the desulfurization slurry water inlet pipe of the primary desulfurization water bed is connected to the cold water outlet pipe of the primary heat exchanger;

[0023] The cold water inlet pipe of the primary heat exchanger is connected to the proximal network circulation mechanism, and the cold water inlet pipe of the primary heat exchanger is connected to the distal primary network circulation mechanism through the first flow regulating valve and the first heat supplement return pipe;

[0024] The hot water outlet pipe of the primary heat exchanger is connected to the proximal network circulation mechanism, and at the same time, the hot water outlet pipe of the primary heat exchanger is connected to the cold water inlet pipe of the steam-water heat exchanger through the first gate valve, the first booster pump and the first heat supplement pipe.

[0025] The beneficial effects of the above-mentioned preferred technical scheme are: the present invention can perform preliminary desulfurization treatment on the flue gas through the cooperation of the first-level desulfurization water bed, the first-level desulfurization slurry circulation pump, the first-level heat exchanger and the steam-water heat exchanger circulation pump, and can preliminarily recover the heat in the flue gas generated by the coal-fired steam boiler, so that the return water of the proximal network can be heated to obtain the proximal network water supply that meets the heating requirements, provide heating for the proximal heat users, and avoid energy waste; and in conjunction with the first flow regulating valve, the first heat supplement pipe, the first gate valve, the first booster pump and the first heat supplement return pipe, the heat in the proximal network can be supplemented to the distal network when the proximal user is overheated and the distal user lacks heat, thereby improving the system operation stability.

[0026] Preferably, the secondary flue gas waste heat recovery mechanism includes a secondary desulfurization water bed, a secondary desulfurization slurry circulation pump, a secondary heat exchanger, an intermediate water pipe, an intermediate water circulation pump and a compression heat pump;

[0027] The flue gas inlet of the secondary desulfurization water bed is connected to the flue gas outlet of the primary desulfurization water bed through the flue, the flue gas outlet of the secondary desulfurization water bed is connected to the chimney through the flue, the desulfurization slurry water outlet pipe of the secondary desulfurization water bed is connected to the hot water inlet pipe of the secondary heat exchanger through the secondary desulfurization slurry circulation pump, and the desulfurization slurry water inlet pipe of the secondary desulfurization water bed is connected to the cold water outlet pipe of the secondary heat exchanger;

[0028] The cold water inlet pipe of the secondary heat exchanger is connected to the cold water outlet pipe of the compression heat pump through the intermediate water pipe, and the hot water outlet pipe of the secondary heat exchanger is connected to the hot water inlet pipe of the compression heat pump through the intermediate water circulation pump and the intermediate water pipe;

[0029] The cold water inlet pipe of the compression heat pump is connected to the remote primary network circulation mechanism, the hot water outlet pipe of the compression heat pump is connected to the cold water inlet pipe of the steam-water heat exchanger, and the hot water outlet pipe of the compression heat pump is connected to the proximal network circulation mechanism through the second flow regulating valve and the second heat supplement pipe, and the compression heat pump is driven by the steam turbine.

[0030] The beneficial effect of the above-mentioned preferred technical solution is: in the present invention, the secondary desulfurization water bed, the secondary desulfurization slurry circulation pump, the secondary heat exchanger, the intermediate water pipe, the intermediate water circulation pump and the compression heat pump cooperate with each other, so that the flue gas can be further desulfurized, so that the gas discharged through the chimney is safe and environmentally friendly, avoiding environmental pollution, and further recycling the heat in the flue gas, thereby improving energy utilization and saving energy.

[0031] Preferably, the waste heat recovery mechanism for sewage includes an absorption heat pump, a sewage channel, a sewage pipe, and a water pump;

[0032] The hot water inlet pipe of the absorption heat pump is connected to the sewage channel through the sewage pipe, the cold water outlet pipe of the absorption heat pump is connected to the sewage channel through the sewage pipe, the cold water inlet pipe of the absorption heat pump is connected to the remote primary network circulation mechanism through the water pump, the hot water outlet pipe of the absorption heat pump is connected to the cold water inlet pipe of the steam-water heat exchanger, and the hot water outlet pipe of the absorption heat pump is connected to the proximal network circulation mechanism through the second flow regulating valve and the second heat supplement pipe.

[0033] Among them, the sewage in the sewage channel comes from domestic sewage after preliminary treatment by the sewage treatment plant. The function of the absorption heat pump is to extract heat from the low-grade heat source and transfer it to the high-grade heat source. The sewage inlet temperature of the currently used absorption sewage source heat pump is about 12°C, and the outlet water temperature is about 7°C.

[0034] The beneficial effect of the above-mentioned preferred technical solution is: in the present invention, the absorption heat pump, sewage channel, sewage pipe, and water pump cooperate with each other to extract low-grade heat from sewage and supplement heat to the heating system, thereby reducing the demand for heat extraction through coal burning, and further reducing pollutant emissions from coal-fired boilers.

[0035] Preferably, the proximal network circulation mechanism includes a proximal network water supply pipe, a proximal network circulation pump, a proximal heat user and a proximal network return pipe;

[0036] The upstream of the proximal network water supply pipe is connected to the hot water outlet pipe of the primary heat exchanger, and the upstream of the proximal network water supply pipe is connected to the hot water outlet pipe of the compression heat pump and the hot water outlet pipe of the absorption heat pump through the second flow regulating valve and the second heat supplement pipe respectively;

[0037] The downstream of the proximal network water supply pipe is connected to the proximal heat user through the proximal network circulation pump;

[0038] The downstream of the proximal heat user is connected to the cold water inlet pipe of the primary heat exchanger through the proximal network return pipe;

[0039] At the same time, the proximal network return water pipe is connected to the distal primary network circulation mechanism through the second gate valve, the second booster pump and the second heat supplement return water pipe.

[0040] The beneficial effects of the above-mentioned preferred technical solution are: the present invention can connect the proximal heat user with the primary heat exchanger circulation through the cooperation of the proximal network water supply pipe, the proximal network circulation pump, the proximal heat user and the proximal network return pipe, thereby realizing water supply circulation, and continuously using the primary heat exchanger to heat the circulating water to meet the heating requirements; and in conjunction with the second flow regulating valve, the second heat supplement pipe, the second gate valve, the second booster pump and the second heat supplement return pipe, the heat in the remote network can be supplemented to the proximal network when the remote user is overheated and the proximal user lacks heat, thereby improving the system operation stability.

[0041] Preferably, the remote primary network circulation mechanism includes a heat network heat exchanger, a remote primary network water supply pipe, a remote primary network circulation pump and a remote primary network return pipe;

[0042] The hot water inlet pipe of the heat network heat exchanger is connected to the steam outlet of the gas boiler and the hot water outlet pipe of the steam-water heat exchanger through the remote primary network water supply pipe and the remote primary network circulation pump, and the cold water outlet pipe of the heat network heat exchanger is connected to the condensed water pipe of the gas boiler and the cold water return pipe of the absorption heat pump through the remote primary network return pipe;

[0043] At the same time, the upstream of the remote primary network return pipe is also connected to the proximal network return pipe through the second heat supplement return pipe, the second booster pump and the second gate valve;

[0044] The heat network heat exchanger is connected to the remote secondary network circulation mechanism to form a closed loop.

[0045] Preferably, the remote secondary network circulation exchange mechanism includes a remote secondary network circulation pump, a remote secondary network water supply pipe, a remote heat user and a remote secondary network return pipe; the remote secondary network circulation pump is connected to the hot water outlet pipe of the heat network heat exchanger upstream, and is connected to the remote heat user downstream through the remote secondary network water supply pipe; the remote heat user is connected to the cold water inlet pipe of the heat network heat exchanger through the remote secondary network return pipe.

[0046] Preferably, the primary desulfurization slurry circulation pump, the secondary desulfurization slurry circulation pump, the intermediate water circulation pump, the proximal network circulation pump, the distal primary network circulation pump and the distal secondary network circulation pump are variable frequency circulation pumps, and the pipe flow can be controlled by setting the power of the variable frequency circulation pump.

[0047] Preferably, the desulfurization slurry water inlet pipe and the desulfurization slurry water outlet pipe are made of stainless steel to prevent the desulfurization slurry from corroding the pipes.

[0048] The present invention also provides a multi-source complementary heating method for cascaded energy utilization, which uses the multi-source complementary heating system for cascaded energy utilization, and comprises the following steps:

[0049] (1) The high-pressure steam generated by the coal-fired steam boiler is input into the steam turbine to perform work and then discharges low-temperature exhaust steam, which is transported to the steam-water heat exchanger through a steam pipe for heat exchange, and the condensed water is returned to the coal-fired steam boiler through a condensed water pipe for heating;

[0050] (2) Flue gas generated during the combustion of coal in a coal-fired steam boiler is transported to a primary desulfurization water bed through a flue for primary desulfurization treatment, and the primary desulfurization slurry is heated. Then, a primary desulfurization slurry circulation pump is started to transport the heated primary desulfurization slurry to a primary heat exchanger for heat exchange with the proximal network return water and then cooled. The cooled primary desulfurization slurry is refluxed to the primary desulfurization water bed. The primary heat exchanger simultaneously heats the proximal network return water to form proximal network supply water.

[0051] (3) starting the proximal network circulation pump to transport the proximal network supply water through the proximal network water supply pipe to the proximal heat user for heating and then cooling, forming the proximal network return water to flow back through the proximal network return pipe to the primary heat exchanger for heating and temperature increase;

[0052] (4) The flue gas after the primary desulfurization treatment enters the secondary desulfurization water bed for secondary desulfurization treatment, and the secondary desulfurization slurry is heated, and then the secondary desulfurization slurry circulation pump is started to transport the heated secondary desulfurization slurry to the secondary heat exchanger for heat exchange with the intermediate water, and the cooled secondary desulfurization slurry is returned to the secondary desulfurization water bed, and the secondary heat exchanger simultaneously heats the intermediate water; and the intermediate water circulation pump is started to transport the heated intermediate water to the compression heat pump for heat exchange with the remote primary network return water and then cool it, and the cooled intermediate water flows back to the secondary heat exchanger for heating, and the compression heat pump is driven by the steam turbine to heat the remote primary network return water to obtain the primary supply water, and the primary supply water is transported to the steam-water heat exchanger for heat exchange with the low-temperature exhaust steam; and the completely desulfurized flue gas is transported to the chimney through the flue and discharged to the outside;

[0053] (5) The sewage in the sewage channel is transported to the absorption heat pump through the sewage pipe to exchange heat with the return water of the remote primary network and then cooled. The cooled sewage flows back to the sewage channel through the sewage pipe. The absorption heat pump heats the return water of the remote primary network to obtain the primary supply water. The primary supply water is transported to the steam-water heat exchanger to exchange heat with the low-temperature exhaust steam.

[0054] (6) The primary water supply is heated up after heat exchange with the low-temperature exhaust steam through the steam-water heat exchanger to obtain remote primary network water supply, and then the remote primary network circulation pump is started to transport the water to the heat network heat exchanger through the remote primary network water supply pipe for heat exchange with the remote secondary network return water. After cooling, the remote primary network return water is transported to the absorption heat pump and the compression heat pump through the remote primary network return pipe for heating. The heat network heat exchanger heats the remote secondary network return water to obtain remote secondary network water supply; at the same time, the remote secondary network circulation pump is started to transport the remote secondary network supply water through the remote secondary network water supply pipe to the remote heat user for heating and then cooled. After cooling, the remote secondary network return water is returned to the heat network heat exchanger through the remote secondary network return pipe;

[0055] (7) When the proximal user is overheated and the distal user is short of heat, the first gate valve and the first booster pump are opened, and the proximal network supply water is transported to the steam-water heat exchanger through the first heat supplement pipe to exchange heat with the low-temperature exhaust steam and then heated to obtain the distal primary network supply water, and then transported to the heat network heat exchanger through the distal primary network supply pipe to exchange heat with the distal secondary network return water, and then cooled to obtain the distal primary network return water; at the same time, the first flow regulating valve is opened to return the distal primary network return water to the primary heat exchanger through the first heat supplement return pipe;

[0056] (8) When the remote user is overheated and the near user is short of heat, the second flow regulating valve is opened to transport the primary water supply to the near network water supply pipe through the second heat supplement pipe, and at the same time, the near network circulation pump is turned on to transport the water to the near heat user through the near network water supply pipe for heating, and the near network return water is formed after cooling; at the same time, the second gate valve and the second booster pump are opened to transport the near network return water to the remote primary network return water pipe through the near network return water pipe and the second heat supplement return water pipe;

[0057] (9) When the heat is insufficient, the gas boiler is turned on to heat the remote primary network return water to obtain the remote primary network supply water. At the same time, the remote primary network circulation pump is started to transport the remote primary network supply water through the remote primary network supply pipe to the heat network heat exchanger for heat exchange with the remote secondary network return water. After cooling, the remote primary network return water is returned to the gas boiler through the remote primary network return pipe for heating.

[0058] Preferably, the high-pressure steam in step (1) has a pressure of 3.11-3.96 MPa and a temperature of 430-480° C., and the low-temperature exhaust steam has a pressure of 0.12 MPa and a temperature of 190° C.;

[0059] The temperature of the primary desulfurization slurry after heating in step (2) is 120-132°C, the temperature of the primary desulfurization slurry after cooling is 84-96°C, the return water temperature of the proximal network is 32-38°C, and the supply water temperature of the proximal network is 45-50°C;

[0060] The temperature of the secondary desulfurization slurry after heating in step (4) is 26-32°C, and the temperature of the secondary desulfurization slurry after cooling is 19-25°C; the temperature of the intermediate water after heating is 19-20°C, and the temperature of the intermediate water after cooling is 15-16°C; the return water temperature of the remote primary network is 40°C, and the primary water supply temperature is 50-55°C;

[0061] In step (5), the temperature of the hot sewage is 12°C, the temperature of the cooled sewage is 7°C, the return water temperature of the remote primary network is 40°C, and the primary water supply temperature is 50-55°C;

[0062] The water supply temperature of the remote primary network in step (6) is 90-95°C;

[0063] The water supply temperature of the remote primary network in step (9) is 90-95°C.

[0064] The beneficial effects of the above-mentioned preferred technical scheme are: a multi-source complementary heating method with cascaded energy utilization disclosed by the present invention has a simple operation method and convenient overall regulation. The waste heat and exhaust steam generated in the production process of the heating system are utilized in a cascade manner to reduce energy waste; at the same time, low-grade heat in sewage can be extracted to supplement heat in the heating system, reducing the demand for coal combustion; and each waste heat recovery device is connected in parallel. If a certain device fails, it will not affect the overall heating effect, thereby improving the stability of the entire system; at the same time, the sub-network operation mode is adopted to effectively reduce heat loss in the heat transmission process, reduce equipment investment, and achieve the ideal effect of optimal energy and optimal use.

[0065] It can be seen from the above technical solutions that, compared with the prior art, the present invention discloses a multi-source complementary heating system and method for cascaded energy utilization, which has the following beneficial effects:

[0066] (1) The use of coal-fired steam boilers combined with a variety of clean energy sources to provide heat increases the heating capacity of the heat source and ensures that the heating needs of heat users are met;

[0067] (2) Use the primary flue gas waste heat recovery mechanism to directly supply heat to the proximal heat users through the proximal network circulation mechanism, and use the secondary flue gas waste heat recovery mechanism, exhaust steam waste heat recovery mechanism, and sewage waste heat recovery mechanism to supply heat to the remote heat users through the remote primary network circulation mechanism and the remote secondary network circulation mechanism. Adopt a separate network operation mode to reduce equipment investment and reduce the energy loss of heating water during transportation, ensuring optimal use of energy;

[0068] (3) The two heat networks are connected by using heat supply pipes and heat supply return pipes to supplement each other's heat under different loads, which improves the linkage coupling of the entire system and reduces the imbalance of the heat network.

[0069] (4) Using coal-fired steam boilers and waste heat recovery devices as the basic heat source and gas boilers as peak-shaving boilers can enable the entire system to quickly adapt to weather changes caused by weather fluctuations;

[0070] (5) The flue gas waste heat recovery device and the sewage source heat pump are used to heat the heating water, and then the exhaust steam is used to raise the temperature again to meet the heating standard. This realizes the cascade utilization of energy, saves about 20% of coal compared to the traditional heating system, and reduces pollutant emissions;

[0071] (6) The secondary flue gas waste heat recovery mechanism and the sewage waste heat recovery mechanism are connected in parallel. If a device fails, it will not affect the overall heating effect, thereby improving the stability of the heating system operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0072] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0073] Figure 1 The accompanying drawing is a schematic structural diagram of a multi-source complementary heating system for cascaded energy utilization provided in Example 1 of the present invention.

[0074] In the figure: 1 is a coal-fired steam boiler, 2 is a steam turbine, 3 is a gas boiler, 4 is a steam pipe, 5 is a steam-water heat exchanger, 6 is a condensate pipe, 7 is a first gate valve, 8 is a first booster pump, 9 is a first heat supplement pipe, 10 is a first flow regulating valve, 11 is a first heat supplement return pipe, 12 is a primary desulfurization water bed, 13 is a primary desulfurization slurry circulation pump, 14 is a primary heat exchanger, 15 is a secondary desulfurization water bed, 16 is a secondary desulfurization slurry circulation pump, 17 is a secondary heat exchanger, 18 is an intermediate water pipe, 19 is an intermediate water circulation pump, 20 is a compression heat pump, 21 is a second flow regulating valve, 22 is a second heat supplement Pipe, 23 is an absorption heat pump, 24 is a sewage channel, 25 is a sewage pipe, 26 is a water pump, 27 is a second gate valve, 28 is a second booster pump, 29 is a second heat supply return pipe, 30 is a proximal network water supply pipe, 31 is a proximal network circulation pump, 32 is a proximal heat user, 33 is a proximal network return pipe, 34 is a heat network heat exchanger, 35 is a remote primary network water supply pipe, 36 is a remote primary network circulation pump, 37 is a remote primary network return pipe, 38 is a remote secondary network circulation pump, 39 is a remote secondary network water supply pipe, 40 is a remote heat user, 41 is a remote secondary network return pipe, 42 is a flue, and 43 is a chimney. DETAILED DESCRIPTION

[0075] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0076] Example 1

[0077] Embodiment 1 of the present invention discloses a multi-source complementary heating system for cascaded energy utilization, including a coal-fired steam boiler, a steam turbine, an exhaust steam waste heat recovery mechanism, a primary flue gas waste heat recovery mechanism, a secondary flue gas waste heat recovery mechanism, a sewage waste heat recovery mechanism, a proximal network circulation mechanism, a distal primary network circulation mechanism, a distal secondary network circulation mechanism, and a gas boiler;

[0078] The high-temperature steam outlet of the coal-fired steam boiler is connected to the steam turbine, and the flue gas outlet is connected to the primary flue gas waste heat recovery mechanism and the secondary flue gas waste heat recovery mechanism in sequence through the flue;

[0079] Among them, the exhaust steam waste heat recovery mechanism includes a steam pipe, a steam-water heat exchanger and a condensate pipe; the steam pipe connects the steam outlet of the steam turbine and the hot water inlet pipe of the steam-water heat exchanger; the cold water outlet pipe of the steam-water heat exchanger is connected to the return pipe of the coal-fired steam boiler through the condensate pipe, the cold water inlet pipe of the steam-water heat exchanger is respectively connected to the secondary flue gas waste heat recovery mechanism and the sewage waste heat recovery mechanism, and the cold water inlet pipe of the steam-water heat exchanger is also connected to the primary flue gas waste heat recovery mechanism through the first gate valve, the first booster pump and the first heat supplement pipe, and the hot water outlet pipe of the steam-water heat exchanger is connected to the remote primary network circulation mechanism.

[0080] In addition, the primary flue gas waste heat recovery mechanism includes a primary desulfurization water bed, a primary desulfurization slurry circulation pump and a primary heat exchanger; the flue gas inlet of the primary desulfurization water bed is connected to the flue gas outlet of the coal-fired steam boiler through the flue, the flue gas outlet of the primary desulfurization water bed is connected to the secondary flue gas waste heat recovery mechanism through the flue, the desulfurization slurry water outlet pipe of the primary desulfurization water bed is connected to the hot water inlet pipe of the primary heat exchanger through the primary desulfurization slurry circulation pump, and the desulfurization slurry water inlet pipe of the primary desulfurization water bed is connected to the cold water outlet pipe of the primary heat exchanger; the cold water inlet pipe of the primary heat exchanger is connected to the proximal network circulation mechanism, and the cold water inlet pipe of the primary heat exchanger is connected to the distal primary network circulation mechanism through the first flow regulating valve and the first heat supplement return pipe; the hot water outlet pipe of the primary heat exchanger is connected to the proximal network circulation mechanism, and at the same time, the hot water outlet pipe of the primary heat exchanger is connected to the cold water inlet pipe of the steam-water heat exchanger through the first gate valve, the first booster pump and the first heat supplement pipe.

[0081] In addition, the secondary flue gas waste heat recovery mechanism includes a secondary desulfurization water bed, a secondary desulfurization slurry circulation pump, a secondary heat exchanger, an intermediate water pipe, an intermediate water circulation pump and a compression heat pump; the flue gas inlet of the secondary desulfurization water bed is connected to the flue gas outlet of the primary desulfurization water bed through a flue, the flue gas outlet of the secondary desulfurization water bed is connected to the chimney through a flue, the desulfurization slurry outlet pipe of the secondary desulfurization water bed is connected to the hot water inlet pipe of the secondary heat exchanger through the secondary desulfurization slurry circulation pump, and the desulfurization slurry inlet pipe of the secondary desulfurization water bed is connected to the secondary heat exchanger. Cold water outlet pipe; the cold water inlet pipe of the secondary heat exchanger is connected to the cold water outlet pipe of the compression heat pump through the intermediate water pipe, and the hot water outlet pipe of the secondary heat exchanger is connected to the hot water inlet pipe of the compression heat pump through the intermediate water circulation pump and the intermediate water pipe; the cold water inlet pipe of the compression heat pump is connected to the remote primary network circulation mechanism, the hot water outlet pipe of the compression heat pump is connected to the cold water inlet pipe of the steam-water heat exchanger, and at the same time, the hot water outlet pipe of the compression heat pump is connected to the near-end network circulation mechanism through the second flow regulating valve and the second heat supplement pipe, and the compression heat pump is driven by the steam turbine.

[0082] In addition, the sewage waste heat recovery mechanism includes an absorption heat pump, a sewage channel, a sewage pipe, and a water pump; the hot water inlet pipe of the absorption heat pump is connected to the sewage channel through the sewage pipe, the cold water outlet pipe of the absorption heat pump is connected to the sewage channel through the sewage pipe, the cold water inlet pipe of the absorption heat pump is connected to the remote primary network circulation mechanism through the water pump, the hot water outlet pipe of the absorption heat pump is connected to the cold water inlet pipe of the steam-water heat exchanger, and at the same time, the hot water outlet pipe of the absorption heat pump is connected to the proximal network circulation mechanism through the second flow regulating valve and the second heat supplement pipe.

[0083] Among them, the sewage in the sewage channel comes from domestic sewage after preliminary treatment by the sewage treatment plant. The function of the absorption heat pump is to extract heat from the low-grade heat source and transfer it to the high-grade heat source. The sewage inlet temperature of the currently used absorption sewage source heat pump is about 12°C, and the outlet water temperature is about 7°C.

[0084] Moreover, the proximal network circulation mechanism includes a proximal network water supply pipe, a proximal network circulation pump, a proximal heat user and a proximal network return pipe; the proximal network water supply pipe is connected to the hot outlet pipe of the primary heat exchanger upstream, and the proximal network water supply pipe is connected to the hot outlet pipe of the compression heat pump and the hot outlet pipe of the absorption heat pump respectively upstream through the second flow regulating valve and the second heat supplement pipe; the proximal network water supply pipe is connected to the proximal heat user downstream through the proximal network circulation pump; the proximal heat user is connected to the cold inlet pipe of the primary heat exchanger downstream through the proximal network return pipe; at the same time, the proximal network return pipe is connected to the distal primary network circulation mechanism through the second gate valve, the second booster pump and the second heat supplement return pipe.

[0085] Thirdly, the remote primary network circulation mechanism includes a heat network heat exchanger, a remote primary network water supply pipe, a remote primary network circulation pump and a remote primary network return pipe; the hot water inlet pipe of the heat network heat exchanger is connected to the steam outlet of the gas boiler and the hot water outlet pipe of the steam-water heat exchanger through the remote primary network water supply pipe and the remote primary network circulation pump respectively, and the cold water outlet pipe of the heat network heat exchanger is connected to the condensate pipe of the gas boiler and the cold water return pipe of the absorption heat pump respectively through the remote primary network return pipe; at the same time, the upstream of the remote primary network return pipe is also connected to the proximal network return pipe through the second heat supply return pipe, the second booster pump and the second gate valve; the heat network heat exchanger is connected to the remote secondary network circulation mechanism to form a closed loop.

[0086] Finally, the remote secondary network circulation exchange mechanism includes a remote secondary network circulation pump, a remote secondary network water supply pipe, a remote heat user and a remote secondary network return pipe; the remote secondary network circulation pump is connected to the hot water outlet pipe of the heat network heat exchanger upstream, and is connected to the remote heat user downstream through the remote secondary network water supply pipe; the remote heat user is connected to the cold water inlet pipe of the heat network heat exchanger through the remote secondary network return pipe.

[0087] In order to further optimize the technical solution, variable frequency circulation pumps are used for the primary desulfurization slurry circulation pump, secondary desulfurization slurry circulation pump, intermediate water circulation pump, proximal network circulation pump, remote primary network circulation pump and remote secondary network circulation pump. The pipe flow can be controlled by setting the power of the variable frequency circulation pump.

[0088] In order to further optimize the technical solution, the desulfurization slurry inlet pipe and the desulfurization slurry outlet pipe are made of stainless steel to prevent the desulfurization slurry from corroding the pipes.

[0089] In order to further optimize the technical solution, the primary heat exchanger, the secondary heat exchanger and the heat network heat exchanger are plate heat exchangers.

[0090] How it works:

[0091] First, after the coal is burned in the coal-fired steam boiler, the condensed water is heated to generate high-pressure steam, which is then input into the steam turbine to drive the compression heat pump to generate low-temperature exhaust steam. The low-temperature exhaust steam is transported to the hot water inlet pipe of the steam-water heat exchanger through the steam outlet of the steam turbine and the steam pipe. After heat exchange and cooling in the steam-water heat exchanger, condensed water is obtained, which is then returned to the coal-fired steam boiler through the cold water outlet pipe of the steam-water heat exchanger, the condensed water pipe, and the return water pipe of the coal-fired steam boiler to continue heating;

[0092] Secondly, the flue gas generated by the combustion of coal in the coal-fired steam boiler is transported to the primary desulfurization water bed through the flue gas outlet of the coal-fired steam boiler, the flue, and the flue gas inlet of the primary desulfurization water bed for primary desulfurization treatment, and the primary desulfurization slurry can be heated at the same time; then the primary desulfurization slurry circulation pump is started, and the heated primary desulfurization slurry is transported to the primary heat exchanger through the desulfurization slurry outlet pipe of the primary desulfurization water bed and the hot water inlet pipe of the primary heat exchanger for heat exchange with the proximal network return water, and the cooled primary desulfurization slurry is returned to the primary desulfurization water bed through the cold water outlet pipe of the primary heat exchanger and the desulfurization slurry inlet pipe of the primary desulfurization water bed, and the primary heat exchanger simultaneously heats the proximal network return water to form proximal network water supply; and at the same time, the proximal network circulation pump is started to transport the proximal network supply water to the proximal heat user through the proximal network water supply pipe for heating and then cool, forming proximal network return water, which is returned to the primary heat exchanger through the proximal network return pipe to continue heating and heating;

[0093] Furthermore, the flue gas after the primary desulfurization treatment enters the secondary desulfurization water bed for secondary desulfurization treatment, and the secondary desulfurization slurry is heated, and then the secondary desulfurization slurry circulation pump is started to transport the heated secondary desulfurization slurry to the secondary heat exchanger for heat exchange with the intermediate water, and the cooled secondary desulfurization slurry is returned to the secondary desulfurization water bed, and the secondary heat exchanger heats up the intermediate water at the same time; and the intermediate water circulation pump is started to transport the heated intermediate water to the compression heat pump for heat exchange with the remote primary network return water and then cool it, and the cooled intermediate water flows back to the secondary heat exchanger for heating, and the compression heat pump is driven by the steam turbine to heat the remote primary network return water to obtain primary supply water, and the primary supply water is transported to the steam-water heat exchanger for heat exchange with the low-temperature exhaust steam; and the completely desulfurized flue gas is transported to the chimney through the flue to be discharged outside;

[0094] Secondly, the sewage in the sewage channel is transported to the absorption heat pump through the sewage pipe to exchange heat with the return water of the primary network and then cooled. The cooled sewage flows back to the sewage channel through the sewage pipe. The absorption heat pump heats the return water of the primary network at the same time to obtain primary supply water, which is transported to the steam-water heat exchanger for heat exchange with the low-temperature exhaust steam.

[0095] Furthermore, the primary water supply is heated up after heat exchange with low-temperature exhaust steam in the steam-water heat exchanger to obtain remote primary network water supply, and then transported to the heat network heat exchanger through the remote primary network water supply pipe for heat exchange with remote secondary network return water. After cooling, the remote primary network return water is transported to the absorption heat pump and the compression heat pump through the remote primary network return pipe for heating. The heat network heat exchanger heats the remote secondary network return water to obtain remote secondary network water supply; at the same time, the remote secondary network circulation pump is turned on to transport the remote secondary network water supply through the remote secondary network water supply pipe to the remote heat user for heating and then cooled. After cooling, the remote secondary network return water is returned to the heat network heat exchanger through the remote secondary network return pipe;

[0096] In addition, when the near-end user is overheated and the far-end user lacks heat, the first gate valve and the first booster pump are opened to transport the near-end network supply water to the steam-water heat exchanger through the first heat supplement pipe for further heating to obtain the far-end primary network supply water, and then transport it to the heat network heat exchanger through the far-end primary network supply pipe for heat exchange with the far-end secondary network return water, and obtain the far-end primary network return water after cooling; at the same time, the first flow regulating valve is opened to return the far-end primary network return water to the primary heat exchanger through the first heat supplement return pipe;

[0097] In addition, when the remote user is overheated and the near user lacks heat, the second flow regulating valve is opened, and the primary water supply is transported to the near network water supply pipe through the second heat supplement pipe, and then transported to the near heat user through the near network water supply pipe under the action of the near network circulation pump for heating, and forms near network return water after cooling; at the same time, the second gate valve and the second booster pump are opened, and the near network return water is transported to the remote primary network return pipe through the near network return pipe and the second heat supplement return pipe;

[0098] Moreover, when the heat is insufficient, the gas boiler is turned on to heat the remote primary network return water to obtain the remote primary network supply water. At the same time, the remote primary network circulation pump is started to transport the remote primary network supply water through the remote primary network water supply pipe to the heat network heat exchanger for heat exchange with the remote secondary network return water. After cooling, the remote primary network return water is returned to the gas boiler through the remote primary network return pipe for heating.

[0099] The present invention discloses a multi-source complementary heating system with cascaded energy utilization. On the one hand, a primary flue gas waste heat recovery mechanism is used to heat the proximal network return water to obtain the proximal network water supply that meets the temperature supply requirements, thereby providing heat to the proximal heat users. On the other hand, a secondary flue gas waste heat recovery mechanism and a sewage waste heat recovery mechanism are used to preliminarily heat the remote primary network circulating return water, which is then further heated by an exhaust steam waste heat recovery mechanism, thereby enabling the remote primary network water supply to meet the temperature supply requirements, thereby providing heat to the remote heat users. Among them, according to the different losses in the heating process between the near-end heat users and the far-end heat users, the sub-network operation mode is adopted, which effectively reduces the heat loss in the heat transmission process, reduces the equipment investment, and achieves the ideal effect of optimal use of energy; and the cascade utilizes the waste heat and exhaust steam generated in the production process of the heating system to reduce energy waste; in addition, the sewage waste heat recovery mechanism is used to extract low-grade heat from the sewage to supplement the heat to the heating system, reducing the demand for heat extraction through coal combustion, thereby reducing the pollutant emissions of coal-fired boilers; at the same time, the secondary flue gas waste heat recovery mechanism and the sewage waste heat recovery mechanism are connected in parallel. If a device fails, it will not affect the overall heating effect, which improves the stability of the overall heating system. In addition, the two heat networks are connected by heat supplement pipes and heat supplement return pipes to supplement each other's heat under different loads; at the same time, a gas boiler that can be quickly started and stopped is set to supplement heat in extremely cold weather to ensure that the linkage coupling of the entire heating system is improved to the greatest extent.

[0100] Example 2

[0101] Embodiment 2 of the present invention discloses a multi-source complementary heating method for cascaded energy utilization, which adopts the multi-source complementary heating system for cascaded energy utilization disclosed in Embodiment 1, and includes the following steps:

[0102] (1) The high-pressure steam generated by the coal-fired steam boiler is input into the steam turbine to perform work and then the low-temperature exhaust steam is discharged. The low-temperature exhaust steam is transported to the steam-water heat exchanger through the steam pipe for heat exchange, and the condensed water is returned to the coal-fired steam boiler through the condensed water pipe for heating; the pressure of the high-pressure steam is 3.11-3.96 MPa and the temperature is 430-480°C, and the pressure of the low-temperature exhaust steam is 0.12 MPa and the temperature is 190°C.

[0103] (2) Flue gas generated during the combustion of coal in a coal-fired steam boiler is transported to a primary desulfurization water bed through a flue for primary desulfurization treatment, and the primary desulfurization slurry is heated to 120-132°C, and then a primary desulfurization slurry circulation pump is started to transport the heated primary desulfurization slurry to a primary heat exchanger for heat exchange with the proximal network return water, and then cooled to 84-96°C, and the cooled primary desulfurization slurry is returned to the primary desulfurization water bed, and the primary heat exchanger simultaneously heats the 32-38°C proximal network return water to form 45-50°C proximal network supply water;

[0104] (3) Start the proximal network circulation pump to transport the proximal network supply water through the proximal network water supply pipe to the proximal heat user for heating and then cool it, forming the proximal network return water to flow back through the proximal network return pipe to the primary heat exchanger for heating and temperature increase;

[0105] (4) The flue gas after the primary desulfurization treatment enters the secondary desulfurization water bed for secondary desulfurization treatment, and the secondary desulfurization slurry is heated to 26-32°C, and then the secondary desulfurization slurry circulation pump is started to transport the heated secondary desulfurization slurry to the secondary heat exchanger for heat exchange with the intermediate water and then cooled to 19-25°C, and the cooled secondary desulfurization slurry is returned to the secondary desulfurization water bed, and the secondary heat exchanger simultaneously heats the intermediate water to 19-20°C; and the intermediate water circulation pump is started to transport the heated intermediate water to the compression heat pump for heat exchange with the 40°C remote primary network return water and then cooled to 15-16°C, and the cooled intermediate water flows back to the secondary heat exchanger for heating, and the compression heat pump is driven by the steam turbine to heat the remote primary network return water to 50-55°C to obtain primary supply water, and the primary supply water is transported to the steam-water heat exchanger for heat exchange with the low-temperature exhaust steam; and the completely desulfurized flue gas is transported to the chimney through the flue to be discharged outside;

[0106] (5) The 12°C sewage in the sewage channel is transported to the absorption heat pump through the sewage pipe and cooled to 7°C after heat exchange with the primary network return water. The cooled sewage flows back to the sewage channel through the sewage pipe. The absorption heat pump heats the 40°C remote primary network return water to 50-55°C to obtain primary supply water. The primary supply water is transported to the steam-water heat exchanger for heat exchange with the low-temperature exhaust steam.

[0107] (6) The primary supply water is heated to 90-95°C after heat exchange with low-temperature exhaust steam in the steam-water heat exchanger to obtain remote primary network supply water, and then the remote primary network circulation pump is started to transport the water to the heat network heat exchanger through the remote primary network water supply pipe for heat exchange with the remote secondary network return water. After cooling, the remote primary network return water is transported to the absorption heat pump and the compression heat pump through the remote primary network return pipe for heating. The heat network heat exchanger heats the remote secondary network return water to obtain the remote secondary network supply water; at the same time, the remote secondary network circulation pump is started to transport the remote secondary network supply water through the remote secondary network water supply pipe to the remote heat user for heating and then cooled. After cooling, the remote secondary network return water is returned to the heat network heat exchanger through the remote secondary network return pipe;

[0108] (7) When the proximal user is overheated and the distal user is short of heat, the first gate valve and the first booster pump are opened to transport the proximal network supply water to the steam-water heat exchanger through the first heat supplement pipe for further heating to obtain the distal primary network supply water, and then transport the proximal network supply water to the heat network heat exchanger through the distal primary network supply pipe for heat exchange with the distal secondary network return water, and obtain the distal primary network return water after cooling; at the same time, the first flow regulating valve is opened to return the distal primary network return water to the primary heat exchanger through the first heat supplement return pipe;

[0109] (8) When the remote user is overheated and the near user is short of heat, the second flow regulating valve is opened, and the primary supply water is transported to the near network water supply pipe through the second heat supplement pipe, and then transported to the near heat user through the near network water supply pipe under the action of the near network circulation pump for heating, and forms near network return water after cooling; at the same time, the second gate valve and the second booster pump are opened, and the near network return water is transported to the remote primary network return pipe through the near network return pipe and the second heat supplement return pipe;

[0110] (9) When the heat is insufficient, the gas boiler is turned on to heat the remote primary network return water to obtain the remote primary network supply water. At the same time, the remote primary network circulation pump is started to transport the remote primary network supply water through the remote primary network supply pipe to the heat network heat exchanger for heat exchange with the remote secondary network return water. After cooling, the remote primary network return water is returned to the gas boiler through the remote primary network return pipe for heating.

[0111] Example 3

[0112] Example 3 of the present invention takes the heating system of a heating company in Shenyang as an example. The company's heat source is a 60MW coal-fired steam boiler and a 20MW gas boiler, the heating area is 1 million square meters, and the indoor standard temperature is 18°C. A heating method for cascade utilization of energy is specifically disclosed, including the following steps:

[0113] (1) The high-pressure steam generated by the coal-fired steam boiler is input into the steam turbine to perform work and then the low-temperature exhaust steam is discharged. The low-temperature exhaust steam is transported to the steam-water heat exchanger through the steam pipe for heat exchange, and the condensed water is returned to the coal-fired steam boiler through the condensed water pipe for heating; the pressure of the high-pressure steam is 3.12 MPa and the temperature is 480°C, and the pressure of the low-temperature exhaust steam is 0.12 MPa and the temperature is 190°C;

[0114] (2) Flue gas generated during the combustion of coal in a coal-fired steam boiler is transported to a primary desulfurization water bed through a flue for primary desulfurization treatment, and the primary desulfurization slurry is heated to 132°C. Then, a primary desulfurization slurry circulation pump is started to transport the heated primary desulfurization slurry to a primary heat exchanger for heat exchange with the near-end network return water and then cooled to 86°C. The cooled primary desulfurization slurry is returned to the primary desulfurization water bed. At the same time, the primary heat exchanger heats the 37°C near-end network return water to form a 46°C near-end network supply water. At this time, the indoor temperature of the near-end heat user reaches 24°C.

[0115] (3) Start the proximal network circulation pump to transport the proximal network supply water through the proximal network water supply pipe to the proximal heat user for heating and then cool it, forming the proximal network return water to flow back through the proximal network return pipe to the primary heat exchanger for heating and temperature increase;

[0116] (4) The flue gas after the primary desulfurization treatment enters the secondary desulfurization water bed for secondary desulfurization treatment, and the secondary desulfurization slurry is heated to 32°C, and then the secondary desulfurization slurry circulation pump is started to transport the heated secondary desulfurization slurry to the secondary heat exchanger for heat exchange with the intermediate water and then cooled to 19°C. The cooled secondary desulfurization slurry is returned to the secondary desulfurization water bed, and the secondary heat exchanger simultaneously heats the intermediate water to 19°C; and the intermediate water circulation pump is started to transport the heated intermediate water to the compression heat pump for heat exchange with the 40°C remote primary network return water and then cooled to 15°C. The cooled intermediate water flows back to the secondary heat exchanger for heating. The compression heat pump is driven by the steam turbine at the same time to heat the remote primary network return water to 52°C to obtain primary supply water, and the primary supply water is transported to the steam-water heat exchanger for heat exchange with the low-temperature exhaust steam; and the completely desulfurized flue gas is transported to the chimney through the flue for discharge;

[0117] (5) The 12°C sewage in the sewage channel is transported to the absorption heat pump through the sewage pipe and cooled to 7°C after heat exchange with the primary network return water. The cooled sewage flows back to the sewage channel through the sewage pipe. The absorption heat pump heats the 40°C remote primary network return water to 52°C to obtain primary supply water. The primary supply water is transported to the steam-water heat exchanger for heat exchange with the low-temperature exhaust steam.

[0118] (6) The primary supply water is heated to 93°C after heat exchange with low-temperature exhaust steam in the steam-water heat exchanger to obtain remote primary network supply water, and then the remote primary network circulation pump is started to transport the water to the heat network heat exchanger through the remote primary network water supply pipe for heat exchange with the remote secondary network return water, and the water is cooled to 40°C to obtain remote primary network return water, which is then transported to the absorption heat pump and the compression heat pump through the remote primary network return pipe for heating. The heat network heat exchanger simultaneously heats the remote secondary network return water to 45°C to obtain remote secondary network supply water; at the same time, the remote secondary network circulation pump is started to transport the remote secondary network supply water through the remote secondary network water supply pipe to the remote heat user for heating, and then cooled to 35°C. After cooling, the remote secondary network return water is obtained and refluxed to the heat network heat exchanger through the remote secondary network return pipe;

[0119] (7) When the proximal user is overheated and the distal user is short of heat, the first gate valve and the first booster pump are opened to transport the proximal network supply water to the steam-water heat exchanger through the first heat supplement pipe for further heating to obtain the distal primary network supply water, and then transport the proximal network supply water to the heat network heat exchanger through the distal primary network supply pipe for heat exchange with the distal secondary network return water, and obtain the distal primary network return water after cooling; at the same time, the first flow regulating valve is opened to return the distal primary network return water to the primary heat exchanger through the first heat supplement return pipe;

[0120] (8) When the remote user is overheated and the near user is short of heat, the second flow regulating valve is opened, and the primary supply water is transported to the near network water supply pipe through the second heat supplement pipe, and then transported to the near heat user through the near network water supply pipe under the action of the near network circulation pump for heating, and forms near network return water after cooling; at the same time, the second gate valve and the second booster pump are opened, and the near network return water is transported to the remote primary network return pipe through the near network return pipe and the second heat supplement return pipe;

[0121] (9) When the heat is insufficient, the gas boiler is turned on to heat the remote primary network return water to obtain the remote primary network supply water. At the same time, the remote primary network circulation pump is started to transport the remote primary network supply water through the remote primary network supply pipe to the heat network heat exchanger for heat exchange with the remote secondary network return water. After cooling, the remote primary network return water is returned to the gas boiler through the remote primary network return pipe for heating.

[0122] In this specification, each embodiment is described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the embodiments can be referred to each other. For the device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant parts can be referred to the method part.

[0123] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A multi-source complementary heating system with cascaded energy utilization, It is characterized in that Including coal-fired steam boilers, steam turbines, exhaust steam waste heat recovery mechanisms, primary flue gas waste heat recovery mechanisms, secondary flue gas waste heat recovery mechanisms, sewage waste heat recovery mechanisms, near-end network circulation mechanisms, remote primary network circulation mechanisms, remote secondary network circulation mechanisms and gas boilers; The high-temperature steam outlet of the coal-fired steam boiler is connected to the steam turbine, and the flue gas outlet is connected to the primary flue gas waste heat recovery mechanism and the secondary flue gas waste heat recovery mechanism in sequence; The steam turbine is driven and connected to the secondary flue gas waste heat recovery mechanism; The exhaust steam waste heat recovery mechanism is connected to the steam turbine upstream and the coal-fired steam boiler downstream; at the same time, the exhaust steam waste heat recovery mechanism is connected to the secondary flue gas waste heat recovery mechanism and the sewage waste heat recovery mechanism upstream and connected to the remote primary network circulation mechanism downstream; the primary flue gas waste heat recovery mechanism is connected to the proximal network circulation mechanism upstream; The secondary flue gas waste heat recovery mechanism and the sewage waste heat recovery mechanism are connected upstream to the remote primary network circulation mechanism; The proximal network circulation mechanism is connected downstream to the distal primary network circulation mechanism; The remote primary network circulation mechanism is connected to the remote secondary network circulation mechanism to form a closed loop; The gas boiler is connected to the remote primary network circulation mechanism to form a closed loop; The exhaust steam waste heat recovery mechanism includes a steam pipe, a steam-water heat exchanger and a condensed water pipe; The steam pipe connects the steam outlet of the steam turbine and the hot water inlet pipe of the steam-water heat exchanger; The cold water outlet pipe of the steam-water heat exchanger is connected to the return pipe of the coal-fired steam boiler, the cold water inlet pipe of the steam-water heat exchanger is respectively connected to the secondary flue gas waste heat recovery mechanism and the sewage waste heat recovery mechanism, and the hot water outlet pipe of the steam-water heat exchanger is connected to the remote primary network circulation mechanism; The primary flue gas waste heat recovery mechanism includes a primary desulfurization water bed, a primary desulfurization slurry circulation pump and a primary heat exchanger; The flue gas inlet of the primary desulfurization water bed is connected to the flue gas outlet of the coal-fired steam boiler, the flue gas outlet of the primary desulfurization water bed is connected to the secondary flue gas waste heat recovery mechanism, the desulfurization slurry water outlet pipe of the primary desulfurization water bed is connected to the hot water inlet pipe of the primary heat exchanger, and the desulfurization slurry water inlet pipe of the primary desulfurization water bed is connected to the cold water outlet pipe of the primary heat exchanger; The cold water inlet pipe of the primary heat exchanger is connected to the proximal network circulation mechanism, and the cold water inlet pipe of the primary heat exchanger is connected to the distal primary network circulation mechanism; The hot water outlet pipe of the first-stage heat exchanger is connected to the proximal network circulation mechanism, and the hot water outlet pipe of the first-stage heat exchanger is connected to the cold water inlet pipe of the steam-water heat exchanger; The secondary flue gas waste heat recovery mechanism includes a secondary desulfurization water bed, a secondary desulfurization slurry circulation pump, a secondary heat exchanger, an intermediate water pipe, an intermediate water circulation pump and a compression heat pump; The flue gas inlet of the secondary desulfurization water bed is connected to the flue gas outlet of the primary desulfurization water bed, the flue gas outlet of the secondary desulfurization water bed is connected to the chimney, the desulfurization slurry water outlet pipe of the secondary desulfurization water bed is connected to the hot water inlet pipe of the secondary heat exchanger, and the desulfurization slurry water inlet pipe of the secondary desulfurization water bed is connected to the cold water outlet pipe of the secondary heat exchanger; The cold water inlet pipe of the secondary heat exchanger is connected to the cold water outlet pipe of the compression heat pump, and the hot water outlet pipe of the secondary heat exchanger is connected to the hot water inlet pipe of the compression heat pump; The cold water inlet pipe of the compression heat pump is connected to the distal primary network circulation mechanism, the hot water outlet pipe of the compression heat pump is connected to the cold water inlet pipe of the steam-water heat exchanger, and the hot water outlet pipe of the compression heat pump is connected to the proximal network circulation mechanism; The waste heat recovery mechanism includes an absorption heat pump, a sewage channel, a sewage pipe, and a water pump; The hot water inlet pipe of the absorption heat pump is connected to the sewage canal, the cold water outlet pipe of the absorption heat pump is connected to the sewage canal, the cold water inlet pipe of the absorption heat pump is connected to the remote primary network circulation mechanism, the hot water outlet pipe of the absorption heat pump is connected to the cold water inlet pipe of the steam-water heat exchanger, and the hot water outlet pipe of the absorption heat pump is connected to the proximal network circulation mechanism.

2. A multi-source complementary heating system with cascaded energy utilization according to claim 1, It is characterized in that The proximal network circulation mechanism includes a proximal network water supply pipe, a proximal network circulation pump, a proximal heat user and a proximal network return pipe; The upstream of the proximal network water supply pipe is connected to the hot water outlet pipe of the primary heat exchanger, and the upstream of the proximal network water supply pipe is respectively connected to the hot water outlet pipe of the compression heat pump and the hot water outlet pipe of the absorption heat pump through the second flow regulating valve and the second heat supplement pipe; The downstream of the proximal network water supply pipe is connected to the proximal heat user through the proximal network circulation pump; The downstream of the proximal heat user is connected to the cold water inlet pipe of the primary heat exchanger through the proximal network return pipe; At the same time, the proximal network return water pipe is connected to the distal primary network circulation mechanism through the second gate valve, the second booster pump and the second heat supplement return water pipe.

3. A multi-source complementary heating system with cascaded energy utilization according to claim 2, It is characterized in that The remote primary network circulation mechanism includes a heat network heat exchanger, a remote primary network water supply pipe, a remote primary network circulation pump and a remote primary network return pipe; The hot water inlet pipe of the heat network heat exchanger is connected to the steam outlet of the gas boiler and the hot water outlet pipe of the steam-water heat exchanger through the remote primary network water supply pipe and the remote primary network circulation pump, and the cold water outlet pipe of the heat network heat exchanger is connected to the condensed water pipe of the gas boiler and the cold water return pipe of the absorption heat pump through the remote primary network return pipe; At the same time, the upstream of the remote primary network return pipe is also connected to the proximal network return pipe through the second heat supplement return pipe, the second booster pump and the second gate valve; The heat network heat exchanger is connected to the remote secondary network circulation mechanism to form a closed loop.

4. A multi-source complementary heating system with cascaded energy utilization according to claim 3, It is characterized in that The remote secondary network circulation exchange mechanism includes a remote secondary network circulation pump, a remote secondary network water supply pipe, a remote heat user and a remote secondary network return pipe; the remote secondary network circulation pump is connected to the hot water outlet pipe of the heat network heat exchanger upstream, and is connected to the remote heat user downstream through the remote secondary network water supply pipe; the remote heat user is connected to the cold water inlet pipe of the heat network heat exchanger through the remote secondary network return pipe.

5. A multi-source complementary heating method with cascaded energy utilization, It is characterized in that A multi-source complementary heating system using the energy cascade utilization as described in any one of claims 1 to 4 comprises the following steps: (1) The high-pressure steam generated by the coal-fired steam boiler is input into the steam turbine to perform work and then discharges low-temperature exhaust steam. The low-temperature exhaust steam is transported to the steam-water heat exchanger through the steam pipe for heat exchange, and the condensed water is returned to the coal-fired steam boiler through the condensed water pipe for heating; (2) Flue gas generated during the combustion of coal in a coal-fired steam boiler is transported to a primary desulfurization water bed through a flue for primary desulfurization treatment, and the primary desulfurization slurry is heated. Then, a primary desulfurization slurry circulation pump is started to transport the heated primary desulfurization slurry to a primary heat exchanger for heat exchange with the proximal network return water and then cooled. The cooled primary desulfurization slurry is returned to the primary desulfurization water bed. The primary heat exchanger simultaneously heats the proximal network return water to form proximal network supply water. (3) starting the proximal network circulation pump to transport the proximal network supply water through the proximal network water supply pipe to the proximal heat user for heating and then cooling, forming the proximal network return water to flow back through the proximal network return pipe to the primary heat exchanger for heating and temperature increase; (4) The flue gas after the primary desulfurization treatment enters the secondary desulfurization water bed for secondary desulfurization treatment, and the secondary desulfurization slurry is heated, and then the secondary desulfurization slurry circulation pump is started to transport the heated secondary desulfurization slurry to the secondary heat exchanger for heat exchange with the intermediate water, and the cooled secondary desulfurization slurry is returned to the secondary desulfurization water bed, and the secondary heat exchanger simultaneously heats the intermediate water; and the intermediate water circulation pump is started to transport the heated intermediate water to the compression heat pump for heat exchange with the remote primary network return water and then cool it, and the cooled intermediate water flows back to the secondary heat exchanger for heating, and the compression heat pump is driven by the steam turbine to heat the remote primary network return water to obtain primary supply water, and the primary supply water is transported to the steam-water heat exchanger for heat exchange with the low-temperature exhaust steam; and the completely desulfurized flue gas is transported to the chimney through the flue to be discharged outside; (5) The sewage in the sewage channel is transported to the absorption heat pump through the sewage pipe to exchange heat with the return water of the remote primary network and then cooled. The cooled sewage flows back to the sewage channel through the sewage pipe. The absorption heat pump heats the return water of the remote primary network to obtain the primary supply water. The primary supply water is transported to the steam-water heat exchanger to exchange heat with the low-temperature exhaust steam. (6) The primary supply water is heated up after heat exchange with the low-temperature exhaust steam through the steam-water heat exchanger to obtain remote primary network supply water, and then the remote primary network circulation pump is started to transport the water to the heat network heat exchanger through the remote primary network water supply pipe for heat exchange with the remote secondary network return water. After cooling, the remote primary network return water is transported to the absorption heat pump and the compression heat pump through the remote primary network return pipe for heating. The heat network heat exchanger heats the remote secondary network return water to obtain remote secondary network supply water. At the same time, the remote secondary network circulation pump is started to transport the remote secondary network supply water through the remote secondary network water supply pipe to the remote heat user for heating and then cooled. After cooling, the remote secondary network return water is returned to the heat network heat exchanger through the remote secondary network return pipe; (7) When the proximal user is overheated and the remote user is short of heat, the first gate valve and the first booster pump are opened, and the proximal network supply water is transported to the steam-water heat exchanger through the first heat supplement pipe to exchange heat with the low-temperature exhaust steam and then heated to obtain the remote primary network supply water, and then transported to the heat network heat exchanger through the remote primary network supply pipe to exchange heat with the remote secondary network return water, and then cooled to obtain the remote primary network return water; at the same time, the first flow regulating valve is opened to return the remote primary network return water to the primary heat exchanger through the first heat supplement return pipe; (8) When the remote user is overheated and the near user is short of heat, the second flow regulating valve is opened to transport the primary water supply to the near network water supply pipe through the second heat supplement pipe, and at the same time, the near network circulation pump is turned on to transport the water to the near heat user through the near network water supply pipe for heating, and the near network return water is formed after cooling; at the same time, the second gate valve and the second booster pump are opened to transport the near network return water to the remote primary network return water pipe through the near network return water pipe and the second heat supplement return water pipe; (9) When the heat is insufficient, the gas boiler is turned on to heat the remote primary network return water to obtain the remote primary network supply water. At the same time, the remote primary network circulation pump is started to transport the remote primary network supply water through the remote primary network supply pipe to the heat network heat exchanger for heat exchange with the remote secondary network return water. After cooling, the remote primary network return water is returned to the gas boiler through the remote primary network return pipe for heating.

6. A multi-source complementary heating method for cascaded energy utilization according to claim 5, It is characterized in that The high-pressure steam in step (1) has a pressure of 3.11-3.96 MPa and a temperature of 430-480°C, and the low-temperature exhaust steam has a pressure of 0.12 MPa and a temperature of 190°C; The temperature of the primary desulfurization slurry after heating in step (2) is 120-132°C, the temperature of the primary desulfurization slurry after cooling is 84-96°C, the return water temperature of the proximal network is 32-38°C, and the supply water temperature of the proximal network is 45-50°C; The temperature of the secondary desulfurization slurry after heating in step (4) is 26-32°C, and the temperature of the secondary desulfurization slurry after cooling is 19-25°C; the temperature of the intermediate water after heating is 19-20°C, and the temperature of the intermediate water after cooling is 15-16°C; the return water temperature of the remote primary network is 40°C, and the primary water supply temperature is 50-55°C; In step (5), the hot sewage temperature is 12°C, the cooled sewage temperature is 7°C, the remote primary network return water temperature is 40°C, and the primary water supply temperature is 50-55°C; The water supply temperature of the remote primary network in step (6) is 90-95°C; The water supply temperature of the remote primary network in step (9) is 90-95°C.

Images