A high back pressure heat supply system and a heat supply method thereof

Abstract

The application discloses a high-back-pressure heat supply system and a heat supply method thereof, and relates to the technical field of heat and electricity energy saving. The application comprises a high-back-pressure steam turbine generator set, a medium-low pressure steam generator set, a primary heat exchanger set, a secondary heat exchanger set and a heat exchange pipe network. The steam input end of the medium-low pressure steam generator set is connected with the high-back-pressure steam turbine generator set through a medium-low pressure steam pipeline. The heat exchange pipe network has a first pipeline and a second pipeline, and the first pipeline is used for heat exchange with the second pipeline. The original steam turbine generator set is reformed to a high-back-pressure heat supply system, the heat supply potential of the generator set is fully tapped, the regional heat supply capacity is obviously improved, and the demand of the heat supply market development is met. The reformed high-back-pressure steam turbine generator set can operate under high back pressure, the exhaust steam temperature of the steam turbine generator set can be improved, and the exhausted steam is used to heat the hot water in the secondary heat exchanger set.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of thermoelectric energy-saving, in particular to a high-back-pressure heat supply system and a heat supply method thereof. BACKGROUND

[0002] In recent years, with the increase of heat supply demand, it is necessary to gradually increase the maximum heat supply capacity of the heat supply system. At present, the thermal power generating unit is in a low-yield and high-cost operation mode, and faces a very severe operating situation. Under this condition, the heat supply reconstruction of the large condensing unit in thermal power generation to provide centralized heating heat source to the surrounding area and industrial steam to enterprises is an important means to increase the income of the power plant. There are many existing heat supply reconstruction methods, including: directly punching a hole in the steam extraction pipeline to extract steam for heat supply, NCB heat supply technology, absorption heat pump, light shaft heat supply and high-back-pressure double-turbine heat supply. The simple punching of a hole in the steam turbine extraction pipeline to extract steam directly heats the heating return water, and the steam heat utilization rate is low. Although the NCB heat supply technology, absorption heat pump, light shaft heat supply and high-back-pressure double-turbine heat supply can improve the steam energy utilization efficiency, the reconstruction cost is high, the operation is complex, the operation cost is high, and part of the reconstruction scheme needs to be reconstructed to the main machine, which has a certain risk. Therefore, a high-back-pressure heat supply system and a heat supply method thereof are proposed. SUMMARY

[0003] The purpose of the present application is to provide a high-back-pressure heat supply system and a heat supply method thereof to solve the problems raised in the background art.

[0004] To achieve the above-mentioned purpose, the present application provides the following technical scheme: a high-back-pressure heat supply system, comprising: a high-back-pressure steam turbine generator unit, a medium-low pressure steam generator unit, a primary heat exchanger group, a secondary heat exchanger group and a heat exchange pipe network, wherein: the steam input end of the medium-low pressure steam generator unit is connected in communication with the high-back-pressure steam turbine generator unit through a medium-low pressure steam pipeline; the heat exchange pipe network has a first pipeline and a second pipeline, the first pipeline is used for heat exchange between the second pipeline, and the second pipeline is used for communication with a user end pipeline; the primary heat exchanger group has a first water inlet, a first water outlet, a first steam inlet and a first steam outlet, and the secondary heat exchanger group has a second water inlet, a second water outlet, a second steam inlet and a second steam outlet; the first water inlet is in communication with the water outlet of the first pipeline, the first water outlet is in communication with the second water inlet, the first steam inlet is in communication with the exhaust steam end of the high-back-pressure steam turbine generator unit, the second steam inlet is in communication with the exhaust steam end of the medium-low pressure steam generator unit, and the second water outlet is in communication with the water inlet of the first pipeline.

[0005] Preferably in the technical solution, the medium-low pressure steam generator set comprises a condensing back pressure steam turbine generator set, which is connected to the high back pressure steam turbine generator set through a medium pressure steam pipeline.

[0006] Preferably in the technical solution, the medium-low pressure steam generator set further comprises a small steam turbine generator set, which is connected to the high back pressure steam turbine generator set through a low pressure steam pipeline.

[0007] Preferably in the technical solution, the primary heat exchanger group comprises a first heat exchanger group; the secondary heat exchanger group comprises a second heat exchanger group and a third heat exchanger group, the second heat exchanger group is used for heat exchange with exhaust steam of the condensing back pressure steam turbine generator set, and the third heat exchanger group is used for heat exchange with exhaust steam of the small steam turbine generator set.

[0008] Preferably in the technical solution, the secondary heat exchanger group further comprises a fourth heat exchanger group, which is connected to the low pressure steam pipeline and used for heat exchange with low pressure steam in the low pressure steam pipeline.

[0009] Preferably in the technical solution, a hot water driving device is further arranged between the primary heat exchanger group and the secondary heat exchanger group, which is used for driving hot water to flow from the primary heat exchanger group to the secondary heat exchanger group.

[0010] Preferably in the technical solution, the hot water driving device is a heat network circulating water pump.

[0011] Based on the high back pressure heat supply system, the present application provides a heat supply method, and the heat supply steps are as follows:

[0012] S1: first, heat exchange the heating return water in the heat exchange pipeline network with exhaust steam of the high back pressure steam turbine generator set in the first heat exchanger group to obtain transition hot water;

[0013] S2: heat exchange the transition hot water in the second heat exchanger group, the third heat exchanger group and the fourth heat exchanger group by the heat network circulating water pump respectively according to the mass ratio to obtain heating hot water;

[0014] S3: heat exchange the heating hot water with return water in the user pipeline network in the heat exchange pipeline network.

[0015] Preferably in the technical solution, the temperature of the heating return water is controlled to be 40-60℃, the temperature of the transition hot water is controlled to be 60-80℃, and the temperature of the heating hot water is controlled to be 85-95℃.

[0016] Preferably in the technical solution, the mass ratio of the transition hot water flowing into the second heat exchanger group, the third heat exchanger group and the fourth heat exchanger group is 0-5:0-4:0-3.

[0017] Compared with the prior art, the present application has the following advantages:

[0018] After the original steam turbine generator set is reformed for high back pressure heating, the heating potential of the generator set is fully tapped, and the regional heating capacity is significantly improved, meeting the demand of the development of the heating market. The reformed high back pressure steam turbine generator set can operate at high back pressure, which can increase the exhaust steam temperature of the steam turbine generator set and utilize the exhausted exhaust steam to heat the hot water in the secondary heat exchanger group. The scheme can significantly improve the heating capacity under the same fuel consumption, thereby improving the energy utilization efficiency.

[0019] Compared with the heating technologies such as NCB heating technology, absorption heat pump, optical axis heating and high back pressure double rotation heating in the market, the present application has the characteristics of less investment, simple system and wide applicability. It reduces the risk of reform and operating cost, and improves the heating capacity and economy of the generator set.

[0020] Through the present application, the standard coal consumption of power generation, the power utilization rate and the standard coal consumption of power supply are significantly reduced, the unit heating capacity is maximized, and the energy saving and consumption reduction results are remarkable. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 The figure is a structural schematic diagram of the present application.

[0022] In the figure: 1, high back pressure steam turbine generator set; 2, first heat exchanger group; 3, condensing back turbine generator set; 4, second heat exchanger group; 5, small turbine generator set; 6, third heat exchanger group; 7, fourth heat exchanger group; 8, heat exchange pipe network; 9, heat network circulating water pump. DETAILED DESCRIPTION

[0023] The technical solutions in the embodiments of the present application will be described clearly and completely below in combination with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0024] It should be noted that, in the description of the present application, the terms "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application.

[0025] In addition, it should be understood that, for the convenience of description, the sizes of various components shown in the drawings are not drawn in accordance with the actual proportional relationship, for example, the thickness or width of certain layers can be exaggerated relative to other layers.

[0026] It should be noted that similar reference numbers and letters represent similar items in the following drawings, and therefore, once an item is defined or described in one drawing, it will not need to be further specifically discussed and described in the description of subsequent drawings.

[0027] Before understanding the present application, it is necessary to make it clear that the generator set mentioned in the present application refers to a combination comprising several steam turbines and generators, which can be one or more. And the heat exchanger set refers to a combination comprising several heat exchangers, which can be one or more. Specifically, in the design, the specific number and specifications of the steam turbines, generators and heat exchangers in the generator set and the heat exchanger set can be selected and determined according to the actual steam supply of the high back pressure steam turbine generator set 1.

[0028] And the high back pressure steam turbine generator set 1 refers to a steam turbine generator set that has been modified for high back pressure. The steam turbine high back pressure heating technology is to increase the exhaust pressure of the low-pressure cylinder of the steam turbine, thereby increasing the exhaust temperature, and further increasing the output of heating hot water to meet the heating requirements of users. The high back pressure heating technology recycles the heat originally discharged from the air cooling island into the natural world, reduces the cold source loss to zero, improves the circulating heat efficiency of the unit, and uses this method to heat without increasing the size of the unit. The cold source loss is recycled, the heating capacity is increased, and the heating area is increased, achieving the purpose of saving heating steam and improving the economic benefit of the steam turbine unit. Since this technology is a very mature existing technology, it will not be described here.

[0029] It should be noted that the heat exchanger is a device for transferring heat from hot fluid to cold fluid, so it needs to continuously input and output hot fluid and cold fluid to exchange heat between them. In this invention, the hot fluid is steam and the cold fluid is water. For the sake of understanding, we call the port of the heat exchanger group that inputs hot fluid the steam inlet, the port that outputs hot fluid the steam outlet, the port that inputs cold fluid the water inlet, and the port that outputs cold fluid the water outlet.

[0030] As shown in Figure 1 The invention provides a technical solution: a high back pressure heating system, a high back pressure steam turbine generator set 1, a medium and low pressure steam generator set, a primary heat exchanger group, a secondary heat exchanger group, and a heat exchange pipe network 8. The heat exchange pipe network 8 has a first pipe and a second pipe. The first pipe is used for heat exchange between the second pipe. The second pipe is used for communication with the user pipe. The high back pressure steam turbine generator set 1 is mainly used for thermal power generation, and the medium and low pressure steam generator set is used for steam power generation. The input end is connected with the high back pressure steam turbine generator set 1 through the medium and low pressure steam pipe. The medium and low pressure steam turbine generator set can extract medium and low pressure steam from the high back pressure steam turbine generator set 1 to generate electricity. At the same time, the medium and low pressure steam generated by the power generation can become exhaust steam and be discharged from the medium and low pressure steam generator set to the secondary heat exchanger group for heat exchange. It not only can improve the supply of hot water in the heating period, but also can improve the energy utilization rate of the whole system. Extracting medium and low pressure steam from the high back pressure steam turbine generator set 1 does not affect the high back pressure steam turbine generator set 1, and can generate a large amount of steam, thereby improving the exhaust steam production in the whole system. The secondary heat exchanger group is used for heating the transition hot water from the primary heat exchanger group. The heat source for heating the transition hot water in the secondary heat exchanger group comes from the high back pressure steam turbine generator set 1 and the medium and low pressure steam generator set. In this system, the pressure in the heat exchange pipe network 8 can be used to drive the hot water in the secondary heat exchanger group. However, in order to control the driving pressure of the hot water in the primary heat exchanger group and the secondary heat exchanger group, a hot water driving device is arranged between the primary heat exchanger group and the secondary heat exchanger group. The hot water driving device is used to drive the hot water in the primary heat exchanger group to flow from the secondary heat exchanger group to the heat exchange pipe network 8. As a preferred embodiment, the hot water driving device is a heat network circulating water pump 9.

[0031] Specifically, the primary heat exchanger group has a first water inlet, a first water outlet, a first steam inlet and a first steam outlet, and the secondary heat exchanger group has a second water inlet, a second water outlet, a second steam inlet and a second steam outlet; the first water inlet is communicated with the water outlet of the first pipeline, the first water outlet is communicated with the second water inlet, the first steam inlet is communicated with the exhaust steam end of the high-back pressure steam turbine generator set 1, the second steam inlet is communicated with the exhaust steam end of the medium-low pressure steam turbine generator set, and the second water outlet is communicated with the water inlet of the first pipeline.

[0032] Specifically, the medium-low pressure steam turbine generator set includes a condensing-back steam turbine generator set 3 and a small steam turbine generator set 5. The condensing-back steam turbine generator set 3 is communicated with the medium-pressure cylinder inside the high-back pressure steam turbine generator set 1 through a medium-pressure steam pipeline. The small steam turbine generator set 5 is communicated with the low-pressure cylinder inside the high-back pressure steam turbine generator set 1 through a low-pressure steam pipeline.

[0033] Specifically, the primary heat exchanger group includes a first heat exchanger group 2, and the secondary heat exchanger group includes a second heat exchanger group 4, a third heat exchanger group 6 and a fourth heat exchanger group 7. The first heat exchanger group 2 is used for heat exchange with the exhaust steam of the high-back pressure steam turbine generator set 1. The second heat exchanger group 4 is used for heat exchange with the exhaust steam of the condensing-back steam turbine generator set 3. The third heat exchanger group 6 is used for heat exchange with the exhaust steam of the small steam turbine generator set 5. The fourth heat exchanger group 7 is communicated with the low-pressure steam pipeline and is used for heat exchange with the low-pressure steam in the low-pressure steam pipeline.

[0034] As shown in Figure 1 Specifically, the steam inlet of the first heat exchanger group 2 is communicated with the exhaust steam end of the high-back pressure steam turbine generator set 1, the water inlet of the first heat exchanger group 2 is communicated with the output end of the heat exchange pipeline network 8, the water outlet of the first heat exchanger group 2 is respectively communicated with the output end inlet of the second heat exchanger group 4, the third heat exchanger group 6 and the fourth heat exchanger group 7, and the water outlet of the second heat exchanger group 4, the third heat exchanger group 6 and the fourth heat exchanger group 7 is respectively communicated with the input end of the heat exchange pipeline network 8. Among them, the steam inlet of the second heat exchanger group 4 is communicated with the exhaust steam end of the condensing-back steam turbine generator set 3, and the steam inlet of the third heat exchanger group 6 is communicated with the exhaust steam end of the small steam turbine generator set 5. In order to drive the hot water to flow in the secondary heat exchanger group, the heat network circulating water pump 9 is arranged on the pipeline communicated with the first heat exchanger group 2, the second heat exchanger group 4, the third heat exchanger group 6 and the fourth heat exchanger group 7.

[0035] Based on the high back pressure heating system, the application provides a heating method of the high back pressure heating system, which uses the high back pressure heating system, and the high back pressure heating system can deliver heating hot water to the heat exchange pipe network 8 through the primary heat exchanger group and the secondary heat exchanger group. The heating hot water used by the user is cooled to form heating return water, which is input into the primary heat exchanger group and the secondary heat exchanger group again to be heated, thereby forming a heating cycle, and the heating steps are as follows:

[0036] S1: first, the heating return water in the heat exchange pipe network 8 is delivered to the first heat exchanger group 2 to exchange heat with the exhaust steam discharged from the high back pressure steam turbine generator set 1, and the transition hot water is obtained, wherein the temperature of the heating return water is controlled to be 40-60℃. Specifically, the temperature of the heating return water can be any one of 40℃, 42℃, 44℃, 46℃, 48℃, 50℃, 52℃, 54℃, 56℃, 58℃ and 60℃, or any temperature between adjacent temperatures. The temperature of the transition hot water is controlled to be 60-80℃, which can be any one of 60℃, 62℃, 64℃, 66℃, 68℃, 70℃, 72℃, 74℃, 76℃, 78℃ and 80℃, or any temperature between adjacent temperatures.

[0037] S2: the transition hot water is delivered to the second heat exchanger group 4, the third heat exchanger group 6 and the fourth heat exchanger group 7 in the mass ratio through the heat network circulating water pump 9 to exchange heat and obtain the heating hot water, and the temperature of the heating hot water is controlled to be 85-95℃. Specifically, the temperature of the heating hot water is controlled to be 85-95℃, wherein the temperature of the heating hot water can be any one of 85℃, 86℃, 87℃, 88℃, 89℃, 90℃, 91℃, 92℃, 93℃, 94℃ and 95℃, or any temperature between adjacent temperatures, and the mass ratio of the transition hot water flowing into the second heat exchanger group 4, the third heat exchanger group 6 and the fourth heat exchanger group 7 is 0-5:0-4:0-3.

[0038] S3: the heating hot water is delivered to the heat exchange pipe network 8 to exchange heat with the return water in the user pipe network.

[0039] As can be seen from the above, in the application, the heating return water can form the heating hot water after two heat exchanges, wherein the first heat exchange of the heating return water is carried out in the first heat exchanger group 2, the heating return water becomes the transition hot water with a higher temperature after the first heat exchange, and the transition hot water becomes the heating hot water after the second heat exchange in the second heat exchanger group 4 or the third heat exchanger group 6 or the fourth heat exchanger group 7. This segmented heating facilitates the control and adjustment of the temperature of the output heating hot water, and the system can obtain the heating hot water with the required temperature.

[0040] Specifically, in the method of the present application, a high back pressure steam turbine generator set 1 with a power generation capacity of 600,000 kWh is taken as an example. The temperature of the heating return water in the whole system is controlled at 50°C, the temperature of the transition hot water is controlled at 70°C, and the temperature of the heating hot water is controlled at 90°C. At this time, the high back pressure steam turbine generator set 1 is started, and the power generation capacity of the high back pressure steam turbine generator set 1 is 450,000 kWh. The exhaust end of the high back pressure steam turbine generator set 1 can generate a large amount of exhaust steam with a pressure of 33 KPa and a temperature of 71°C, and 26,567 tons of hot water can be heated from the heating return water to the transition hot water per hour by the exhaust steam. The condensing back turbine generator set 3 can extract the medium pressure steam from the medium pressure cylinder of the high back pressure steam turbine generator set 1 through the medium pressure steam pipeline to generate power. The medium pressure steam is superheated steam, and specifically, the pressure of the extracted medium pressure steam is 0.9 Mpa to 1.2 Mpa, which can be any one of 0.9 Mpa, 1.0 Mpa, 1.1 Mpa and 1.2 Mpa, or any pressure between adjacent pressures. The temperature of the medium pressure steam is 380°C, and the flow rate is 350 t / h to 450 t / h. In this embodiment, the pressure of the extracted medium pressure steam is 1.0 Mpa, the temperature is 380°C, and the flow rate is 400 t / h. At this time, the power generation capacity of the condensing back turbine generator set 3 is 38,000 kWh, and the exhaust end of the condensing back turbine generator set 3 can output exhaust steam with a pressure of 0.25 Mpa and a temperature of 230°C, which can be used to heat the transition hot water to the heating hot water through the second heat exchanger group 4. The second heat exchanger group 4 can heat 11,703 tons of transition hot water to heating hot water per hour. At the same time, the small turbine generator set 5 can extract low pressure steam from the low pressure cylinder of the high back pressure steam turbine generator set 1 through the low pressure steam pipeline to generate power. Specifically, the low pressure steam is superheated steam, and the pressure of the extracted low pressure steam is 0.6 Mpa to 0.8 Mpa, which can be any one of 0.6 Mpa, 0.7 Mpa and 0.8 Mpa, or any pressure between adjacent pressures. The temperature of the low pressure steam is 300°C, and the flow rate is 250 t / h to 350 t / h. In this embodiment, the pressure of the extracted low pressure steam is 0.8 Mpa, the temperature is 330°C, and the flow rate is 300 t / h. At this time, the power generation capacity of the small turbine generator set 5 is 25,000 kWh, and the exhaust end of the small turbine generator set 5 can output exhaust steam with a pressure of 0.2 Mpa and a temperature of 200°C, which can be used to heat the transition hot water to the heating hot water through the third heat exchanger group 6. The third heat exchanger group 6 can heat 8,578 tons of transition hot water to heating hot water per hour.At the same time, the low-pressure steam pipeline can also deliver low-pressure steam to the fourth heat exchanger group 7 to perform heat exchange, and the steam flow is 150 t / h to 250 t / h, and in the embodiment, the steam flow is 200 t / h, which can heat 6286 tons of transition hot water into heating hot water per hour.

[0041] The high back pressure steam turbine generator set 1 before the modification, with a power generation of 600,000 kWh, generates electricity with the same input energy (total: 8.08*10^12j, about 276 tons of coal), and the power generation is 600,000 kWh, which can heat 17455 tons of heating return water into heating hot water per hour. The power generation and water supply per hour of the statistical embodiment and the comparative example are counted, and the energy utilization rate is calculated. Energy utilization efficiency=(power generation energy+heating water energy) / input energy*100%, and the specific results are shown in Table 1:

[0042] Table 1

[0043] Item Example Comparative Example Power generation 513,000 kWh 6,000,000 kWh Heating water amount 26567 tons 17455 tons Power generation energy 1.8468*10^12j 2.1580*10^12j Heating water energy 4.4633*10^12j 2.9324*10^12j Energy utilization efficiency 78.1％ 63％

[0044] From Table 1, it can be seen that the energy utilization efficiency of the high back pressure steam turbine generator set after modification is greatly improved.

[0045] Although the embodiments of the present application have been shown and described, it can be understood by those skilled in the art that various changes, modifications, replacements and variations can be made to the embodiments without departing from the principles and spirits of the present application, and the scope of the present application is defined by the appended claims and their equivalents.

Claims

1. A high back pressure heating system, characterized in that: include: High back pressure steam turbine generator set (1), medium and low pressure steam generator set, primary heat exchanger set, secondary heat exchanger set, heat exchange pipe network (8), wherein: The steam input end of the medium and low pressure steam generator set is connected to the high back pressure steam turbine generator set (1) through the medium and low pressure steam pipeline; The heat exchange pipe network (8) comprises a first pipe and a second pipe, wherein the first pipe is used for exchanging heat with the second pipe, and the second pipe is used for communicating with a user-end pipe; The primary heat exchanger group has a first water inlet, a first water outlet, a first steam inlet and a first steam outlet, and the secondary heat exchanger group has a second water inlet, a second water outlet, a second steam inlet and a second steam outlet; the first water inlet is connected to the water outlet of the first pipe, the first water outlet is connected to the second water inlet, the first steam inlet is connected to the exhaust steam end of the high back pressure steam turbine generator set (1), the second steam inlet is connected to the exhaust steam end of the medium and low pressure steam generator set, and the second water outlet is connected to the water inlet of the first pipe; The medium- and low-pressure steam generator set comprises a condensing back steam turbine generator set (3) and a small steam turbine generator set (5), wherein the condensing back steam turbine generator set (3) is connected to the medium-pressure cylinder inside the high-back-pressure steam turbine generator set (1) through a medium-pressure steam pipeline, and the small steam turbine generator set (5) is connected to the low-pressure cylinder inside the high-back-pressure steam turbine generator set (1) through a low-pressure steam pipeline; The secondary heat exchanger group comprises: a second heat exchanger group (4) and a third heat exchanger group (6); the second heat exchanger group (4) is used for exchanging heat with exhaust steam discharged from the condensing back steam turbine generator group (3); and the third heat exchanger group (6) is used for exchanging heat with exhaust steam discharged from the small steam turbine generator group (5).

2. The high back pressure heating system according to claim 1, characterized in that: The primary heat exchanger group comprises: a first heat exchanger group (2).

3. The high back pressure heating system according to claim 2, characterized in that: The secondary heat exchanger group further comprises: a fourth heat exchanger group (7), the fourth heat exchanger group (7) being connected to the low-pressure steam pipeline and being used for exchanging heat with the low-pressure steam in the low-pressure steam pipeline.

4. The high back pressure heating system according to claim 3, characterized in that: A hot water driving device is further provided between the primary heat exchanger group and the secondary heat exchanger group, and the hot water driving device is used to drive hot water to flow from the primary heat exchanger group to the secondary heat exchanger group.

5. The high back pressure heating system according to claim 4, characterized in that: The hot water driving device is a heat network circulating water pump (9).

6. A heating method using the high back pressure heating system according to claim 5, characterized in that: The heating steps are as follows: S1: First, the heating return water in the heat exchange pipe network (8) is transported to the first heat exchanger group (2) to exchange heat with the exhaust steam discharged from the high back pressure steam turbine generator group (1) to obtain transition hot water; S2: The transition hot water is respectively transported to the second heat exchanger group (4), the third heat exchanger group (6) and the fourth heat exchanger group (7) according to the mass ratio through the heat network circulating water pump (9) for heat exchange, thereby obtaining heating hot water; S3: The heating hot water is transported to the heat exchange pipe network (8) to exchange heat with the return water in the user pipe network.

7. The heating method of the high back pressure heating system according to claim 6, characterized in that: The temperature of the heating return water is controlled to be 40°C to 60°C, the temperature of the transition hot water is controlled to be 60°C to 80°C, and the temperature of the heating hot water is controlled to be 85°C to 95°C.

8. The heating method of the high back pressure heating system according to claim 6, characterized in that: The mass ratio of the transition hot water flowing into the second heat exchanger group (4), the third heat exchanger group (6) and the fourth heat exchanger group (7) is 0-5:0-4:0-3.

Images