Steam exhaust gradient utilization heat supply system based on steam ejector

Abstract

The dead steam gradient utilization heat supply system comprises a boiler, a high-pressure cylinder, an intermediate-pressure cylinder, a low-pressure cylinder, a power generator, a steam increasing machine, a steam increasing machine condenser, a deaerator, an air cooling condenser, a high-back-pressure condenser, heat supply network backwater, a heat supply network heater and heat supply network water supply and steam exhaust equipment. An inlet of the boiler is connected with outlets of the high-pressure cylinder and the deaerator, and an outlet is connected with inlets of the high-pressure cylinder and the medium-pressure cylinder. An outlet of the medium-pressure cylinder is connected with inlets of the low-pressure cylinder, the steam increasing machine, the deaerator and the heat supply network heater; an outlet of the low-pressure cylinder is connected with inlets of the air-cooled condenser, the high-back-pressure condenser and the steam increasing machine; an outlet of the steam-increasing machine is connected with an inlet of the steam-increasing machine condenser. The steam exhaust waste heat of the steam turbine and the steam increasing machine and steam extraction of the pressure cylinder in the unit are utilized in a gradient mode, and heat supply network water supply gradient heating is achieved; steam turbine exhaust gas with low energy grade is fully utilized, unit cold end loss is reduced, unit combined heat and power generation cost is reduced, and combined heat and power generation benefits and unit peak load regulation capacity are improved.

Description

Technical Field

[0001] The utility model relates to the field of energy systems, and in particular to a steam ejector-based exhaust steam cascade utilization heating system. Background Art

[0002] Optimizing the energy mix and gradually shifting from reliance on fossil fuels to clean energy, such as the widespread use of renewable energy sources like wind power and solar power, is a key step in achieving emission reduction targets. Therefore, the power industry must pursue a two-pronged approach to promoting green and low-carbon development: developing new energy sources while also tapping into the energy-saving and emission-reduction potential of existing resources.

[0003] In the heating sector, reducing heating costs to improve economic efficiency and expand profit margins has become a challenge that companies must face. This is especially true under high backpressure heating conditions, where exhaust steam from turbines cannot be fully utilized and is directly discharged, resulting in energy waste. Accurately calculating the amount of waste heat recovered and the potential power generation losses incurred due to this recovery becomes particularly important. This helps to find the optimal balance between heating demand and power generation efficiency, achieving a win-win situation for both economic and environmental benefits.

[0004] In response to the multiple difficulties faced by coal-fired units, such as increased pressure for deep peak regulation, reduced annual utilization hours due to changes in electricity market demand, and rising costs caused by fluctuations in global coal market prices, exhaust steam recovery technology has emerged as an important technical means to solve these problems. Through innovative process design, this technology effectively recovers the heat energy in the exhaust steam originally planned to be discharged, converting it into heat required for heating or directly using it in other industrial production processes, thereby reducing heat energy losses. The application of exhaust steam recovery technology can effectively reduce heating costs because the recovered waste heat reduces the need for new heat sources, thereby saving fuel consumption and related operating expenses. At the same time, the recovered heat energy can also be converted into electricity or thermal energy products for sale, increasing the company's revenue source. Summary of the Invention

[0005] The utility model provides a steam ejector-based exhaust steam cascade utilization heating system, the technical purpose of which is to recover low-grade waste heat of turbine exhaust steam in large quantities and flexibly, reduce heat loss at the cold end of the unit, reduce the cost of cogeneration, and increase the income of the heating unit.

[0006] The above technical objectives of the present invention are achieved through the following technical solutions:

[0007] A steam ejector-based exhaust steam cascade utilization heating system, characterized in that it includes: a boiler, a high-pressure cylinder, a medium-pressure cylinder, a low-pressure cylinder, a generator, a steam booster, a steam booster condenser, a deaerator, an air-cooled condenser, a high back-pressure condenser, a heat network return water, a heat network heater, a heat network water supply and an exhaust device; the inlet of the boiler is connected to the outlet of the high-pressure cylinder and the deaerator, and the outlet is connected to the inlet of the high-pressure cylinder and the medium-pressure cylinder; the outlet of the medium-pressure cylinder is connected to the inlet of the low-pressure cylinder, the steam booster, the deaerator and the heat network heater; the low-pressure cylinder The outlet is connected to the air-cooled condenser, the high back-pressure condenser and the inlet of the steam booster, wherein the inlet of the high back-pressure condenser collects the heat from the low-pressure cylinder; the outlet of the steam booster is connected to the inlet of the steam booster condenser and serves as the heat source of the steam booster condenser; the inlet of the exhaust equipment is connected to the drain outlet of the high back-pressure condenser, the steam booster condenser and the heat network heater. The heat network return water flows through the high back-pressure condenser, the steam booster condenser and the heat network heater in sequence, and becomes the heat network supply water after three-stage heating, which is used for cascade heating.

[0008] Furthermore, the high-pressure cylinder, medium-pressure cylinder, low-pressure cylinder and generator are connected in sequence.

[0009] Furthermore, the heat source of the steam booster condenser is the extraction steam from the intermediate pressure cylinder and the exhaust gas from the low pressure cylinder.

[0010] Furthermore, the heat source of the high back pressure condenser is low pressure cylinder exhaust gas.

[0011] Furthermore, the heat source of the heat network heater is the exhaust steam of the medium pressure cylinder.

[0012] The advantages of the utility model are:

[0013] (1) The cascade heating of the feed water in the heating network is achieved by utilizing the exhaust heat of the steam turbine and the steam booster and the steam extracted from the intermediate pressure cylinder of the unit;

[0014] (2) Make full use of the turbine exhaust gas with lower energy quality to reduce the cold end loss of Unit 2, reduce the cost of cogeneration of the unit, and improve the income of cogeneration and the peak load regulation capacity of the unit. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is a structural diagram of the combined heat and power system of the present invention;

[0016] Among them: 1- boiler, 2- high-pressure cylinder, 3- medium-pressure cylinder, 4- low-pressure cylinder, 5- generator, 6- steam turbine, 7- steam turbine condenser, 8- deaerator, 9- air-cooled condenser, 10- high back-pressure condenser, 11- heat network return water, 12- heat network heater, 13- heat network water supply, 14- exhaust equipment. DETAILED DESCRIPTION

[0017] The following is a detailed description of the technical solution of this application in conjunction with the accompanying drawings. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0018] like Figure 1 As shown, the cogeneration system of the present invention includes: a boiler 1, a high-pressure cylinder 2, a medium-pressure cylinder 3, a low-pressure cylinder 4, a generator 5, a steam booster 6, a steam booster condenser 7, a deaerator 8, an air-cooled condenser 9, a high back-pressure condenser 10, a heating network return water 11, a heating network heater 12, a heating network water supply 13, an exhaust device 14 and corresponding working fluid pipelines.

[0019] The outlet of the low-pressure cylinder 4 is connected to the inlet of the air-cooled condenser 9, the inlet of the high back-pressure condenser 10 and the inlet of the steam booster 6, and the inlet of the high back-pressure condenser 10 collects the heat from the low-pressure cylinder 4; the outlet of the medium-pressure cylinder 3 is connected to the inlet of the steam booster 6, the deaerator 8 and the heat network heater 12; the outlet of the steam booster 6 is connected to the heat source inlet of the steam booster condenser 7; the heat source inlet of the heat network heater 12 is the exhaust steam of the medium-pressure cylinder 3; the inlet of the exhaust equipment 14 is connected to the drain outlet of the high back-pressure condenser 10, the drain outlet of the steam booster condenser 7 and the drain outlet of the heat network heater 12, thereby forming a steam exhaust cascade utilization heating system based on steam ejectors.

[0020] The heat network return water 11 flows sequentially through the high back-pressure condenser 10, the steam booster condenser 7, and the heat network heater 12. After three stages of heating, it becomes the heat network feed water 13, achieving cascade heating of the heating feed water. Ultimately, a cascaded exhaust steam utilization heating system based on steam ejectors is formed.

[0021] This system features three stages of heating, enabling large-scale and flexible recovery of exhaust steam for preheating. The first stage's heat source comes from the high-back-pressure condenser 10, the second stage's heat source comes from the booster condenser 7, and the third stage's heat source comes from the extraction steam from the intermediate-pressure cylinder 3. The high-back-pressure condenser 10's heat source is the exhaust steam from the low-pressure cylinder 4, while the booster condenser 7's heat source is the extraction steam from the intermediate-pressure cylinder 3 and the exhaust steam from the low-pressure cylinder 4.

[0022] The high-back-pressure condenser 10 and the booster condenser 7 fully utilize the exhaust heat from the unit's steam turbine, raising the water-side inlet temperature of the heating network heaters and achieving cascade heating of the heating network water. Through first- and second-stage heating, the amount of steam extracted from the turbine for return water heating is reduced, ensuring that the unit's peak-shaving capacity is not significantly restricted during periods of high heating demand.

[0023] The advantages of the utility model are:

[0024] (1) The cascade heating system utilizes the exhaust heat of the steam turbine and steam booster and the steam extracted from the intermediate pressure cylinder of the unit to achieve cascade heating of the feed water in the heating network;

[0025] (2) Make full use of the turbine exhaust gas with lower energy quality, reduce the cold end loss of the unit, reduce the cost of cogeneration of the unit, and improve the income of cogeneration and the peak load regulation capacity of the unit.

[0026] The above is only a preferred embodiment of the present invention, and other effective embodiments are all possible. For other technicians in the same technical field, if effective improvements are proposed based on the present invention, these improvements should also be considered within the scope of protection of the present invention.

Claims

1. A steam ejector-based exhaust steam cascade utilization heating system, characterized in that: include: Boiler (1), high-pressure cylinder (2), medium-pressure cylinder (3), low-pressure cylinder (4), generator (5), steam booster (6), steam booster condenser (7), deaerator (8), air-cooled condenser (9), high back-pressure condenser (10), heat network return water (11), heat network heater (12), heat network water supply (13) and exhaust equipment (14); the inlet of the boiler (1) is connected to the outlet of the high-pressure cylinder (2) and the deaerator (8), and the outlet is connected to the inlet of the high-pressure cylinder (2) and the medium-pressure cylinder (3); the outlet of the medium-pressure cylinder (3) is connected to the inlet of the low-pressure cylinder (4), the steam booster (6), the deaerator (8) and the heat network heater (12); the outlet of the low-pressure cylinder (4) is connected to the outlet ... outlet of the low-pressure cylinder (4) and the medium-pressure cylinder (4). The inlet of the air-cooled condenser (9), the high back pressure condenser (10) and the steam booster (6) is connected, wherein the inlet of the high back pressure condenser (10) receives heat from the low pressure cylinder (4); the outlet of the steam booster (6) is connected to the inlet of the steam booster condenser (7) and serves as a heat source for the steam booster condenser (7); the inlet of the exhaust equipment (14) is connected to the high back pressure condenser (10), the steam booster condenser (7) and the drain outlet of the heat network heater (12); the heat network return water (11) flows through the high back pressure condenser (10), the steam booster condenser (7) and the heat network heater (12) in sequence, and becomes the heat network supply water (13) after three-stage heating for cascade heating.

2. The exhaust steam cascade utilization heating system based on steam ejectors according to claim 1 is characterized in that: The high-pressure cylinder (2), the medium-pressure cylinder (3), the low-pressure cylinder (4), and the generator (5) are connected in sequence.

3. The exhaust steam cascade utilization heating system based on steam ejectors according to claim 1 is characterized in that: The heat sources of the steam booster condenser (7) are the extraction steam from the intermediate pressure cylinder (3) and the exhaust gas from the low pressure cylinder (4).

4. The exhaust steam cascade utilization heating system based on steam ejectors according to claim 1 is characterized in that: The heat source of the high back pressure condenser (10) is the exhaust gas from the low pressure cylinder (4).

5. The exhaust steam cascade utilization heating system based on steam ejectors according to claim 1 is characterized in that: The heat source of the heat network heater (12) is the exhaust steam of the medium pressure cylinder (3).

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