Cogeneration unit heat supply extraction steam residual pressure utilization system

Abstract

The application provides a heat and power cogeneration unit heat supply extraction steam residual pressure utilization system, which comprises a gas supply unit and a heating unit, wherein the gas supply unit comprises a boiler (4), a high-pressure cylinder (1) communicated with the boiler (4), a medium-pressure cylinder (2) communicated with the high-pressure cylinder (1), and a low-pressure cylinder (3) communicated with the medium-pressure cylinder (2); the system further comprises a residual pressure utilization unit, which comprises a vortex tube (10) connected with the medium-pressure cylinder (2) through an extraction steam pipe (31); the system further comprises a heat network heat exchanger, and hot gas flow at a hot end of the vortex tube (10) sequentially passes through a hot end pipe (34), the heat network heat exchanger (7) and a return pipe (35) into a condenser (6); a cold end of the vortex tube (10) is connected into the condenser (6) through a cold end pipe (36); and a heat user (8) is connected to the heat network heat exchanger (7) through a heat exchange pipeline (37); because the vortex tube separates the inflow of the extraction steam pipe into cold gas flow or gas-liquid mixture with lower temperature and hot gas flow with higher temperature, the temperature of the hot gas flow after entering the heat network heat exchanger is higher than the temperature of the traditional extraction steam, and the larger heat transfer temperature difference means that, under the premise of constant heat exchange amount of the heat exchanger, the heat exchanger area can be greatly reduced, and the investment cost and land occupation of the heat exchanger are reduced; meanwhile, the product at the cold end outlet directly enters the condenser, and the required cold load of the condenser is also reduced, and the operation cost of the air cooler is reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of industrial energy saving, and particularly relates to a system for utilizing residual pressure of heat supply extraction steam in a combined heat and power unit. BACKGROUND

[0002] Industrial residual pressure mainly refers to the differential pressure energy generated in industrial production processes and not utilized, and usually refers to pressure energy that can be recycled and utilized but has not been recycled and utilized. There are mainly two sources: 1) by-product with pressure generated along with the process; and 2) working medium that needs pressure to be conveyed or meet the process pressure requirement and has residual pressure after use. From the current situation of the industry in China, the residual pressure resource mainly exists in the ironmaking of blast furnaces, natural gas transportation, central heating pipe network, reverse osmosis seawater desalination and other production processes.

[0003] Combined heat and power (CHP) is an efficient energy utilization method that generates both electricity and useful heat in one process to improve energy efficiency. CHP refers to a process that uses a heat engine or power plant to generate both electricity and useful heat. This technology can significantly improve the thermal efficiency of fuel, as it converts the heat energy that is usually wasted in traditional power generation into useful heat energy for heating, industrial processes or other applications. In a CHP system, the heat energy generated by fuel combustion is first used for power generation, usually through a steam turbine or a gas turbine. The waste heat after power generation is used for heating or refrigeration, realizing the cascade utilization of energy. The CHP system can be "first power generation" or "second power generation". In the first power generation system, the boiler steam is first used for power generation, and then the residual heat energy is used for heating; while in the second power generation system, the steam is first used for industrial processes, and then the residual heat energy is used for power generation.

[0004] In a CHP system, residual pressure utilization refers to the effective utilization of the pressure and temperature of the turbine exhaust steam to further improve the energy utilization rate of the system. This usually involves the use of residual heat recovery devices such as waste heat boilers or heat pumps to capture and utilize the residual heat. Residual pressure utilization has wide applications in areas such as district heating, industrial processes, and domestic hot water supply. For example, in cold winter regions, residual heat can be used to provide heating for residential and commercial buildings; in the industrial field, residual heat can be used to heat raw materials or as part of the production process. In a CHP unit with extraction steam for heating, especially in a unit modified for heating, the extraction steam parameters are often higher than the required values for heating, which on the one hand affects the safe operation of the heat exchanger, and on the other hand the steam work potential is not fully utilized, resulting in a decrease in the efficiency of the heating field. To solve the problem of mismatched heating extraction steam parameters, the extraction steam can be throttled and cooled by a pressure reducer before being exchanged in the heat exchanger. This method is widely used due to its simple equipment structure and adjustment mode. However, this method causes a large amount of heat energy loss due to the use of a throttle valve, and still cannot effectively utilize the work potential of the extraction steam. SUMMARY

[0005] In view of the problems in the prior art, the purpose of the present application is to provide a heat and power cogeneration unit heat extraction steam residual pressure utilization system, heat and power cogeneration refers to the process of using a heat engine or power station to simultaneously generate electricity and useful heat, so the residual pressure energy generated during the operation of the heat and power cogeneration system can be efficiently recovered and utilized using a vortex tube. Compared with the traditional technology of using a throttle valve to extract steam from the intermediate pressure cylinder for pressure reduction, the system uses a vortex tube to separate the cold and hot steam extracted from the intermediate pressure cylinder using residual pressure, separates and converts the energy in the high-speed airflow, which can be used for refrigeration, turbine power generation or heating the circulating water of the heat user, significantly improving the comprehensive utilization rate of energy. Specifically, it comprises a gas supply unit and a heating unit.

[0006] The gas supply unit comprises a boiler, a high-pressure cylinder communicating with the boiler, an intermediate-pressure cylinder communicating with the high-pressure cylinder, and a low-pressure cylinder communicating with the intermediate-pressure cylinder.

[0007] The heating unit comprises a low-pressure heater communicating with the low-pressure cylinder, a high-pressure heater communicating with the high-pressure cylinder and the intermediate-pressure cylinder, a condenser communicating with the low-pressure heater and the low-pressure cylinder, and a deaerator communicating with the low-pressure heater and the high-pressure heater.

[0008] It also comprises a residual pressure utilization unit comprising a vortex tube connected to the intermediate-pressure cylinder through a steam extraction pipe, and a heat network heat exchanger, the hot gas flow at the hot end of the vortex tube sequentially passes through the hot end pipe, the heat network heat exchanger and the return pipe into the condenser, the cold end of the vortex tube is connected to the condenser through the cold end pipe, and the heat user is connected to the heat network heat exchanger through the heat exchange pipe.

[0009] The vortex tube has a scroll chamber and an inlet nozzle, a cold end and a hot end communicating with the scroll chamber, and further comprises:

[0010] An inlet drive structure comprising a cylinder and a ring structure driven to rotate by the cylinder, a main inflow pipe connected to the inlet nozzle, an inflow branch pipe communicating with the cylinder rodless cavity, and a piston rod of the cylinder drivingly connected to the ring structure.

[0011] A control valve piece located between the valve seat and the nozzle, the control valve piece being capable of adjusting the opening degree of the nozzle and controlling the flow of the inflow in the inlet nozzle under the drive of the ring structure; when the inflow pressure rises, part of the inflow gas enters the cylinder rodless cavity through the inflow branch pipe, the piston rod of the cylinder drives the ring structure to rotate and expands the flow area of the inlet nozzle by rotating the control valve piece, automatically adapting to higher inlet pressure and flow.

[0012] The high-pressure cylinder is a subcritical boiler, and the steam temperature of the high-pressure cylinder is about 540℃, and the working pressure is 15.7-19.6Mpa.

[0013] The intermediate pressure cylinder is located after the high pressure cylinder. The exhaust pressure of the intermediate pressure cylinder is guaranteed to be above 0.4 MPa, and the exhaust temperature is around 240℃. The extraction pressure of the intermediate pressure cylinder is 0.3 MPa-0.5 MPa, and the temperature is 134-152℃.

[0014] The beneficial effects described in this application are as follows:

[0015] 1) Compared to the traditional technique of using a throttle valve to reduce the pressure of steam extracted from the intermediate-pressure cylinder, this embodiment uses a vortex tube to separate the hot and cold steam extracted from the cylinder using residual pressure, thus replacing the throttle valve in the existing technology. The hot-end outlet temperature rises to generate superheated steam, increasing the heat exchange capacity of the steam, which then enters the heat network heater for heat exchange, saving heat exchange area. The cold-end outlet temperature decreases, and some of the gas can even condense. The cooled gas-liquid mixture enters the air cooler, which can also reduce the cooling load of the air cooler. Of course, the working fluid at the hot and cold ends can also be mixed by an ejector before entering the air cooler. It can be seen that the residual pressure utilization system, by using a vortex tube in conjunction with the heat network heat exchanger and condenser, can improve the efficiency of heat exchange and condensation in the heat network, thereby reducing the size of the heat network heat exchanger and condenser. In the construction of cogeneration units, this can significantly reduce the investment cost of the heat network heat exchanger and condenser heat exchanger, and significantly improve economic benefits.

[0016] 2) When a phase change occurs inside the vortex tube, the condensate that is precipitated can be discharged from the cold end of the vortex tube and then directly enter the condenser to mix with the fluid returning from the return tube, thereby improving the condensation effect of the condenser. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the heat extraction steam pressure utilization system of the cogeneration unit used in this invention.

[0018] Figure 2 This is a three-dimensional schematic diagram of the inlet self-adjusting structure of the vortex tube in this invention to cope with changes in incoming flow pressure.

[0019] Figure 3 for Figure 2 Side view.

[0020] Figure 4 for Figure 3 AA section diagram.

[0021] Figure 5 According to Figure 1 Location map of the proposed cogeneration heating extraction steam residual pressure utilization system.

[0022] Explanation of reference numerals in the attached figures:

[0023] 1. High pressure cylinder; 2. Medium pressure cylinder; 3. Low pressure cylinder; 4. Boiler; 5. Deaerator; 6. Condenser; 7. Heat network heat exchanger; 8. Heat user; 9. Hot steam temperature reducer; 10. Vortex tube; 11. Inlet nozzle; 12. First control ring; 13. Second control ring; 14. Adjusting block; 15. Control pull rod; 16. Control valve piece; 17. Spout; 18. Valve seat; 19. Driving block; 21. High pressure heater; 22. Low pressure heater; 31. Extraction pipe; 32. Cooling steam pipe; 33. Medium pressure discharge pressure reduction branch; 34. Hot end pipe; 35. Backflow pipe; 36. Cold end pipe; 37. Heat exchange pipeline. DETAILED DESCRIPTION

[0024] In order to make the above objectives, features and advantages of the present application more obvious and easy to understand, the specific embodiments of the present application are described in detail below with reference to the accompanying drawings.

[0025] Although the present application is disclosed as above, the present application is not limited thereto. In the description of the present specification, the description of the terms "one embodiment", "some embodiments", "exemplary embodiment", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In the present specification, the exemplary description of the above terms does not necessarily mean the same embodiment or example. Also, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present application, and therefore the scope of protection of the present application should be defined by the scope defined in the claims.

[0026] Gas supply unit

[0027] Figure 1 is a schematic diagram of a heat and power cogeneration unit heat supply extraction pressure utilization system, which converts steam energy into mechanical energy to drive a generator, while providing steam for heating of a heat user 8.

[0028] The boiler 4 is a device for generating steam, which functions to heat water into high-temperature and high-pressure steam. In a steam supply unit, the steam generated by the boiler first enters the high pressure cylinder to do work, and then passes through the medium pressure cylinder and the low pressure cylinder in turn, to finally complete the step-by-step utilization of energy. For a subcritical pressure boiler, the outlet steam pressure is 15.7-19.6 MPa; while for a supercritical pressure boiler, the outlet steam pressure exceeds the critical pressure of 22.1 MPa, and the supercritical pressure adopted by a power plant boiler is usually between 25-27 MPa, while the temperature range of the steam is determined according to the heating demand and the technical index of the equipment, and generally the steam leaving the boiler has a temperature of about 540°C.

[0029] The high-pressure cylinder 1 is the part of the steam turbine that withstands the highest pressure and temperature, usually made of materials that can withstand high temperatures and pressures. In a steam turbine unit, the high-pressure cylinder receives high-temperature and high-pressure steam from the boiler and expands to drive the turbine to rotate, thereby driving the generator to generate electricity. Its working pressure is usually matched with the boiler outlet pressure, so it can be considered the same as the boiler. For a subcritical boiler, the steam temperature of the high-pressure cylinder is around 540°C, and the working pressure is 15.7-19.6 MPa.

[0030] The intermediate-pressure cylinder 2 is located behind the high-pressure cylinder and receives the steam discharged from the high-pressure cylinder. Here, the pressure and temperature of the steam are reduced, but still maintain a high level. The design of the intermediate-pressure cylinder considers the balance between cost and efficiency, usually using medium-temperature-resistant materials, and may use a single-layer cylinder structure to reduce cost. Regarding the specific working pressure and temperature of the intermediate-pressure cylinder, there may be differences due to different combined heat and power system unit designs and heating and power supply needs. Generally, the working pressure of the intermediate-pressure cylinder will be lower than that of the high-pressure cylinder, and the temperature will also be correspondingly reduced. To ensure the safety of the last-stage blades of the intermediate-pressure cylinder, the exhaust pressure is generally guaranteed to be above 0.4 MPa, and the exhaust temperature is generally around 240°C. Regarding the extraction of the intermediate-pressure cylinder, to ensure the safety of heating and heating needs, the extraction pressure is 0.3-0.5 MPa, and the temperature is 134-152°C.

[0031] The low-pressure cylinder 3 is the last stop in the steam energy conversion process. Here, the temperature and pressure of the steam reach the lowest point. The low-pressure cylinder is characterized by its large size, as it needs to handle a large amount of low-temperature steam. It is usually made of ordinary steel and may use a welded double-layer cylinder structure in terms of structure to improve strength and durability. Its steam pressure is usually 0.1-0.5 MPa, which allows the steam to further expand and convert into mechanical energy.

[0032] The deaerator 5 is used to remove dissolved oxygen and other gases from the boiler feedwater to prevent corrosion of the boiler equipment and piping caused by oxygen, prolonging the service life of the equipment.

[0033] The condenser 6 is mainly used to condense the low-pressure steam discharged from the steam turbine into water for recycling. In a steam turbine unit, the condenser also plays a role in maintaining the system vacuum, improving the thermal efficiency of the entire system.

[0034] The cooling steam pipe 33 is an important component for cooling the intermediate-pressure cylinder 2. During the operation of the steam turbine, the intermediate-pressure cylinder will generate a large amount of heat, which may cause overheating and even damage to the equipment if not cooled in time. The cooling steam pipe effectively reduces the temperature of the intermediate-pressure cylinder by introducing cooling steam, ensuring the normal operation and long-term stability of the equipment.

[0035] The intermediate pressure discharge branch 32 is an important pipeline connecting the intermediate pressure cylinder and the low pressure cylinder. Its main function is to reduce the pressure of the steam entering the low pressure cylinder to ensure smooth flow and energy conversion of the steam in the low pressure cylinder. The existence of the intermediate pressure discharge branch makes the steam turbine flexible to adjust the flow and pressure of the steam under different loads, thereby improving the adaptability and economy of the equipment.

[0036] The high pressure heater 21 is a device that uses part of the steam turbine's extraction to heat the feedwater. It is a prior art that consists of two parts: shell and tube system. The upper part of the shell cavity is provided with a steam condensation section, and the lower part is provided with a drain cooling section. The top of the inlet and outlet water pipes is provided with a feedwater inlet and a feedwater outlet. When superheated steam enters the shell through the inlet, it can heat the feedwater in the upper main spiral pipe. After the steam condenses into water, the condensed hot water can heat part of the feedwater in the lower drain spiral pipe. The condensed water after being used flows out of the body through the drain outlet.

[0037] The function of the low pressure heater 22 is to use the steam that has done part of the work in the steam turbine to heat the feedwater in the heater, thereby increasing the temperature of the water and reducing the amount of steam discharged from the steam turbine to the condenser, thereby reducing energy loss and improving the circulating efficiency of the thermal system. The structure is more commonly used in vertical tube plate type heater. The heating surface of the heater is generally composed of straight tube bundles or U-shaped tube bundles composed of brass tubes or seamless steel tubes. The heated water enters the water chamber on one side from the upper inlet pipe, then flows into the U-shaped tube bundle, and the U-shaped tube absorbs the heat of the heating steam in the steam space of the heater and transfers it to the water flowing in the tube. The heated water flows out through the outlet water chamber of the heater.

[0038] The hot steam desuperheater 9 is a device used to reduce the temperature of steam. Its main function is to reduce the temperature of steam to an appropriate level before it enters the steam turbine, to protect the steam turbine from overheating damage. The working principle of the hot steam desuperheater is based on the principle of heat exchange. When high temperature steam flows through the desuperheater, it exchanges heat with the cooling medium (usually water or air) inside the desuperheater. In this way, the temperature of the steam is reduced, while the cooling medium absorbs the heat of the steam and is heated. Direct contact desuperheater uses cooling water to directly mix with steam, and reduces the temperature of steam by evaporation of water to absorb heat. Indirect contact desuperheater uses metal or other heat-conducting materials as heat transfer medium to transfer heat between steam and cooling water without directly mixing the two. This type of desuperheater usually has better control performance and higher efficiency.

[0039] Principle of combined heat and power system operation

[0040] Water is heated into high pressure and high temperature steam in the boiler 4, the steam pressure is in, these steam first into the high pressure cylinder 1 to do work, then in turn through the medium pressure cylinder 2 and low pressure cylinder 3, finally complete the energy cascade utilization, and in this process to push the turbine rotation to generate electricity. In this process, the use of steam turbine high pressure cylinder 1 and medium pressure cylinder 2 part of the extraction steam in the high pressure heater 21 for heating water, these superheated steam after three rounds of heating after condensation into water and into the deaerator 5 to remove dissolved oxygen in water; From the low pressure cylinder 3 to do the steam into the low pressure heater 22 heating feed water to improve its temperature, so as to reduce the steam turbine to the condenser 6 discharge, reduced the condenser 6 condensing load, improve the system circulation efficiency. In addition, the hot steam desuperheater 9 can be before the superheated steam into the steam turbine, by exchanging heat between the steam and the cooling medium inside the desuperheater 9 to reduce the steam temperature to the appropriate level, so as to protect the steam turbine from overheating damage.

[0041] Surplus pressure utilization system operating principle

[0042] Surplus pressure utilization unit, which is a surplus pressure utilization equipment added in front of the heat network heat exchanger, which includes a vortex tube 10, the vortex tube 10 is connected with the medium pressure cylinder 2 through the extraction pipe 31. Vortex tube is a device that can divide the compressed gas into cold gas flow and hot gas flow two parts, its working principle is based on the vortex effect and fluid dynamics principle. When the compressed gas enters the vortex chamber in a high speed rotating manner through the nozzle, a free vortex is formed. Due to the difference in angular velocity, friction is generated between the layers of free vortex, resulting in the temperature of the gas flow in the center part to be reduced, becoming cold gas flow, while the temperature of the gas flow in the peripheral part is increased, becoming hot gas flow. This separation leads to the formation of temperature gradient, so that cold gas is released at one end and hot gas is released at the other end, which is realized by the high energy of the entering compressed gas in the vortex tube. In this embodiment, the inlet of the vortex tube utilizes the surplus pressure of the medium pressure cylinder extraction steam, which separates the steam into cold gas flow and hot gas flow. It should be noted that the cold and hot gas flow here is a relative description relative to the inlet of the vortex tube.

[0043] As can be seen, the high temperature steam extracted from the medium pressure cylinder 2 enters the self-regulating vortex tube 10 through the extraction pipe 31, and the high temperature steam is separated into cold gas flow and hot gas flow through the vortex tube, so as to achieve the purpose of utilizing the surplus pressure of the combined heat and power system, and the outlet pressure can be reduced to meet the threshold of the heating system. Since the temperature of the hot gas flow is higher than the extraction steam temperature, the hot gas flow is introduced into the heat network heat exchanger 7 to heat the heat network circulating water returning to the heat network heat exchanger from the heat user 8. After heating the circulating water, the temperature of the hot gas flow is reduced and enters the condenser through the connecting pipe 35 and mixes with the cold gas flow. The heated circulating water also reaches the heating temperature to continue heating the heat user.

[0044] The excess pressure utilization unit further comprises a heat network heat exchanger, which is mainly used for heating circulating water in a hot water supply system by using steam extracted from the steam turbine or generated by the boiler to meet the heating demand. In a shell-and-tube structure, a heat medium (such as steam) flows in the inner side of the tube, and the heat-exchanged substance passes through the shell outside the tube to exchange heat. Heat exchange is completed through the wall of the tube to cool the heat medium or heat the heat-exchanged substance.

[0045] The hot gas stream at the hot end of the vortex tube 10 passes through the hot end tube 34, the heat network heat exchanger 7 and the return tube 35 in sequence to enter the condenser 6, the cold end of the vortex tube 10 is connected to the condenser 6 through the cold end tube 36, and the heat user 8 is connected to the heat network heat exchanger 7 through the heat exchange pipeline 37. When phase change occurs in the vortex tube, the condensed water separated out can be discharged from the cold end of the vortex tube and then directly enter the condenser 6 to mix with the fluid returned by the return tube 35, thereby improving the condensing effect of the condenser 6.

[0046] Since the vortex tube 10 separates the incoming flow of the steam extraction tube 31 into cold gas stream and hot gas stream, the temperature of the hot gas stream entering the heat network heat exchanger 7 is higher than the temperature of the conventional steam extraction, and the larger heat transfer temperature difference means that, under the premise that the heat exchange amount of the heat exchanger is unchanged, the heat exchanger area can be greatly reduced, and the investment cost and land occupation of the heat exchanger are reduced; at the same time, the product at the cold end outlet directly enters the condenser, which can also reduce the cold load required by the condenser and reduce the operation cost of the air cooler. That is, the volume or heat exchange area of the heat network heat exchanger 7 can be reduced. The cold gas stream separated by the vortex tube 10 directly enters the condenser 6, which also reduces the heat exchange pressure of the condenser 6, so the volume or heat exchange area of the condenser 6 can also be reduced.

[0047] Compared with the traditional technology of using a throttle valve to reduce the pressure of steam extracted from the intermediate-pressure cylinder, the steam extracted from the cylinder in the embodiment is used to separate cold and hot by using the residual pressure of the vortex tube, so that the throttle valve in the prior art is replaced, the temperature of the hot-end outlet is increased to generate superheated steam, the heat exchange capacity of the steam is increased, the heat exchanger in the heat supply network is used for heat exchange, and the heat exchange area can be saved; the temperature of the cold-end outlet is reduced, and part of the gas can even be condensed, the gas-liquid mixture with the reduced temperature is fed into the air cooler, and part of the air cooling load can be reduced; of course, the working medium of the hot-end outlet and the cold-end outlet can also be mixed by using an ejector and then fed into the air cooler. Therefore, the residual pressure utilization system can improve the efficiency of heat supply network heat exchange and condensation by using the vortex tube 10 in combination with the heat supply network heat exchanger 7 and the condenser 6, so that the sizes of the heat supply network heat exchanger 7 and the condenser 6 are reduced, the investment cost of the heat supply network heat exchanger 7 and the condenser 6 is greatly reduced in the construction of the combined heat and power unit, and the economic benefit is significantly improved. Compared with the residual pressure utilization system in which the extracted steam is heated to heat circulating water by using a throttle valve, the residual pressure utilization system integrated with the vortex tube has a greater heat exchange temperature difference and a higher degree of fluid turbulence, and therefore has a stronger heat exchange capacity, reduces the heat exchange area required by the heat exchanger, and reduces the economic cost. In addition, due to the separation effect of the vortex tube, the cold gas flow is mixed with the hot gas flow after heat exchange, and the temperature of the gas-liquid mixture is lower than that of the conventional residual pressure utilization system, which to some extent also reduces the condensing load of the condenser, and therefore reduces the economic cost.

[0048] According to actual engineering experience, the vortex tube is regarded as an isenthalpic process, the inlet temperature of the vortex tube is consistent with the extracted steam temperature, which is 134-152 ℃, and the inlet pressure is 0.3-0.5 MPa; the prior art research shows that when the cold flow ratio is 0.76, if the cold-end outlet and the inlet pressure ratio is calculated according to 0.25, the approximate range of the hot-end pressure value can be calculated according to the mass conservation principle and the energy conservation principle. However, to calculate the accurate values of the hot-end outlet temperature rise and the cold-end outlet temperature drop, numerical simulation calculation needs to be performed according to the parameters such as the state of the cold-end outlet steam and the hot-end outlet steam, the enthalpy, and the specific heat capacity. h =P in *(1-c) / c. However, to calculate the accurate values of the hot-end outlet temperature rise and the cold-end outlet temperature drop, numerical simulation calculation needs to be performed according to the parameters such as the state of the cold-end outlet steam and the hot-end outlet steam, the enthalpy, and the specific heat capacity.

[0049] Heat supply network heat exchanger: when the system power is 300 MW, the steam saturation pressure is 0.07-0.14 MPa, the design temperature of the water supply is 120-130 ℃, the actual temperature of the water supply is 80-100 ℃, the design return water temperature is 70 ℃, the actual return water temperature is 50 ℃, and the upper end difference of the heat exchanger is 10 ℃.

[0050] Self-regulating vortex tube

[0051] The vortex tube 10 is a device for energy separation by using high-speed rotating airflow. By injecting compressed gas into the vortex tube, the compressed gas is made to rotate at high speed in the tube, so as to realize temperature separation and form cold and hot gas flows. In the specific embodiment, the flow size of the vortex tube is adjusted according to the parameters (temperature and pressure) of the vortex tube inflow, and the vortex tube is always kept in an optimal working state, so as to cope with the fluctuation of the inflow of the high-temperature steam extracted from the intermediate pressure cylinder 2 through the steam extraction pipe 31 into the self-adjusting vortex tube 10. The self-adjusting vortex tube is described in detail in the prior application CN2024112063768 of the applicant, and in the specific embodiment, the self-adjusting vortex tube is applied to a combined heat and power system to prevent damage to the rear-end equipment caused by the inflow fluctuation of the steam extraction pipe 31.

[0052] The self-adjusting vortex tube has a vortex chamber and an inlet nozzle 11, a cold end pipe and a hot end pipe which are all in communication with the vortex chamber. On the basis of the main structure of the vortex tube, a piston cylinder and an inlet transmission structure are added, that is, Figure 2 The inlet transmission structure in the above formula includes a cylinder and a ring structure driven to rotate by the cylinder. The main inflow pipe is connected with the inlet nozzle 11, the branch inflow pipe is communicated with the rodless cavity of the cylinder, and the piston rod of the cylinder is drivingly connected with the ring structure.

[0053] The control valve plate 16 is located between the valve seat 18 and the nozzle 17, and can adjust the opening of the nozzle 17 and control the flow of the inflow in the inlet nozzle 11 under the drive of the ring structure. When the inflow pressure rises, part of the inflow gas enters the rodless cavity of the cylinder through the branch inflow pipe, the piston rod of the cylinder 8 drives the ring structure to rotate and expands the flow area of the inlet nozzle 11 by rotating the control valve plate 16, so as to automatically adapt to the higher inlet pressure and flow.

[0054] In use, if the inflow pressure rises, part of the inflow gas enters the piston cylinder through the bypass, the gas pressure above the cylinder of the self-adjusting vortex tube increases and pushes the piston to move downward, thereby driving the peripheral ring of the inlet transmission device to rotate clockwise, and then pushing the control pull rod to move inward, and squeezing the movable valve plate to expand the area of the inlet nozzle of the vortex tube, so as to adapt to the higher inlet pressure and flow. When the inflow pressure decreases, part of the gas in the piston cylinder leaves the cylinder and flows into the main pipe from the bypass, the gas pressure above the cylinder decreases and pulls the piston to move upward, thereby driving the peripheral ring of the inlet transmission device to rotate counterclockwise, and then pulling the control pull rod to move outward, and the movable valve plate rebounds to reduce the area of the inlet nozzle of the vortex tube, so as to adapt to the lower inlet pressure and flow. Thus, the device realizes that the vortex tube pressure reduction system can maintain a relatively stable outflow state under different inflow pressures.

[0055] The self-adjusting vortex tube cylinder driven adaptive adjustment structure can quickly respond when the fluid pressure fluctuates, thereby coping with the change of the incoming flow of the high-temperature steam extracted from the middle cylinder 2 through the steam extraction pipe 31 into the self-adjusting vortex tube 10, reducing the shock and over-adjustment of the system. Moreover, the cylinder can adapt to harsh environments such as high temperature, high pressure, corrosive medium, etc., ensuring the normal operation of the valve under these conditions, which helps to maintain the stable operation of the production line.

[0056] Referring to Figures 2-4 Further comprising: a circular ring structure is coaxially installed with the vortex tube, the circular ring structure is provided with an adjusting block 14, the side of the vortex chamber is provided with a driving block 19, the driving block 19 can control the rotation of the valve plate 16 relative to the valve seat 18, the driving control pull rod 15 passes through the adjusting block 14 and is connected with the driving block 19.

[0057] In this embodiment, the inlet nozzle 11 is multiple and uniformly distributed in the circumferential direction, which can better accelerate the high-pressure incoming flow of gas and form a high-speed rotating flow, creating conditions for energy separation. When the gas passes through the inlet nozzle 11, it will expand rapidly and accelerate to form a strong rotating airflow. This rotating airflow produces an energy separation effect inside the vortex chamber, causing the temperature of the gas to differ between the center and the periphery.

[0058] The circular ring structure is used to synchronously control the valve opening of the multiple inlet nozzles 11, so it is selected to be coaxially installed with the self-adjusting vortex tube, the gas pressure above the cylinder increases and extrudes the piston to move downward, thereby driving the peripheral circular ring of the inlet transmission device to rotate clockwise, the side of the vortex chamber is provided with a driving block 19, the driving block 19 can control the rotation of the valve plate 16 relative to the valve seat 18, the driving control pull rod 15 passes through the adjusting block 14 and is connected with the driving block 19, when the gas pressure above the cylinder of the self-adjusting vortex tube increases and extrudes the piston to move downward, thereby driving the peripheral circular ring structure of the inlet transmission device to rotate clockwise, the circular ring structure further rotates the driving block 19 by pushing the control pull rod 15, the driving block 19 further rotates the valve plate 16, and the angles of rotation of the multiple control valve plates 16 are the same, so the openings of the multiple nozzles 11 are also the same. Figure 4 In this embodiment, the circular ring structure includes a first control circular ring 12 and a second control circular ring 13, the adjusting block 14 is rotatably arranged between the first control circular ring 12 and the second control circular ring 13, and the hole of the adjusting block 14 is slidably connected with the control pull rod 15. The driving block 19 includes a sleeve and a shaft outside the sleeve, the sleeve is fixedly connected with the control pull rod 15, and the shaft passes through the side of the vortex chamber and is fixedly connected with the control valve plate 16.

[0059]

[0060] ​When the ring structure rotates and pushes the control rod 15, the relative position of the control rod 15 and the adjusting block 14 also changes due to the change in position. Sliding displacement occurs between the control rod 15 and the hole of the adjusting block 14. This sliding fit between the hole and the shaft can prevent motion interference between the transmission components.

[0061] In this embodiment, a reset element is also included, which can maintain the control valve plate 16 at a preset opening degree of the nozzle 17 or restore it to the preset opening degree of the nozzle 17.

[0062] The reset element is existing technology, such as using a spring sleeved on the cylinder piston rod. When the incoming flow pressure returns to the preset value, the cylinder piston can return to the preset position under the action of the spring. That is, the entire self-adjusting vortex tube resets.

[0063] This embodiment also includes a hot-end self-adjusting component, and further includes:

[0064] The temperature conduction module consists of a bimetallic structure 7 and a linkage lever. The temperature conduction module can transfer heat to the bimetallic structure 7 and is connected to the main inlet pipeline and the hot end outlet of the vortex tube respectively. When the bimetallic structure 7 changes shape according to temperature changes, it drives the linkage lever to move. The linkage lever is connected to the regulating valve 5. The regulating valve 5 can move along the axial direction of the hot end pipe 4 and adjust the opening of the hot end outlet of the vortex tube.

[0065] The hot-end self-adjusting component is used to control the hot-end control valve to adjust the hot-end outlet area according to the temperature of the incoming gas, thereby adjusting the flow rate at the hot-end outlet of the vortex tube, and further adjusting the flow ratio between the hot and cold ends of the vortex tube.

[0066] The bimetallic structure is composed of two different metals. This composite structure leverages the advantages of each metal and produces a synergistic effect, thereby improving overall performance. In a temperature adaptive control system, the bimetallic structure is used in conjunction with a temperature conduction module to respond to changes in the incoming flow temperature based on the temperatures of the main inlet pipeline and the hot end outlet of the vortex tube.

[0067] Economic Benefit Analysis

[0068] This embodiment presents a calculation method for the economic benefit analysis of the aforementioned combined heat and power (CHP) unit's exhaust steam pressure utilization system. It should be noted that this method is only a preferred calculation method and should not be considered a limitation of the aforementioned technology.

[0069] To facilitate system analysis and research, this embodiment... Figure 1 Mark the points as follows: Figure 5 As shown, a simplified mathematical model is proposed before data analysis:

[0070] 1) The behavior of water vapor in the vortex tube is referenced to air with the same parameters;

[0071] 2) All points in the entire system are in a steady state during operation;

[0072] 3) Ignore pressure losses caused by each connecting pipe;

[0073] 4) The process in the vortex tube is an isenthalpic process.

[0074] 1. Energy Analysis

[0075] First, monitoring instruments were installed at key locations such as the inlet and outlet of the vortex tube and the inlet and outlet of the heat exchanger to monitor parameters such as temperature, pressure, flow rate, and humidity in real time. Mass and energy conservation equations were established for each component, including the boiler, turbine, heater, vortex tube, and heat exchanger. Based on the first law of thermodynamics, the enthalpy changes at the inlet and outlet of each component were calculated under specified operating conditions to obtain the energy and mass changes of steam in each heat exchange process, and the energy conversion efficiency and losses were evaluated. Finally, the experimental results of the integrated vortex tube residual pressure utilization system and the system using a throttling valve for airflow depressurization were compared and analyzed, and improvement measures to increase energy conversion efficiency and reduce energy losses were proposed.

[0076] For residual pressure utilization systems, the enthalpy values ​​at the inlet and outlet of the vortex tube can be calculated using the following formula:

[0077] h out =h in -η nozzle (h in -h out,is ), where η nozzle Isentropic efficiency refers to the degree to which the gas state change during the operation of a vortex tube approximates an isentropic process. The isentropic efficiency η is... nozzle Determined by multiple factors such as the cooling flow ratio, pressure ratio, and structural design, a vortex tube with high isentropic efficiency means lower energy loss and superior performance. Therefore, the mass and energy conservation equations for a vortex tube are as follows: m in =m cold +m hot h in =ch cold +(1-c)h hot c is the cold flow ratio of the vortex tube.

[0078] according to Figure 5 Based on the point diagram and the above assumptions, the mass and energy conservation equations for the residual pressure utilization system of the integrated vortex tube are as follows:

[0079]

[0080] 2 analyze

[0081] As the maximum available energy in the system, it reflects the irreversibility of the energy conversion process. Similarly, based on data such as temperature, pressure, and flow rate, calculations are performed for each stage of both actual cogeneration cycles and integrated vortex tube cogeneration cycles. Values, including inputs Output and Loss. By comparing inputs. With useful output The ratio of integrated vortex tube residual pressure utilization system to airflow depressurization system using throttle valve is compared and analyzed. Efficiency and The main links in the loss. Finally, regarding... For links where losses are significant, suggestions should be made to reduce irreversibility and improve... Efficiency improvement measures.

[0082] Each state point The formula for calculating the value is as follows:

[0083] E x = m[(h-h0)-T0(s-s0)], where h0 and s0 are the specific enthalpy and specific entropy of the steam at the reference point. Generally, the ambient temperature T0 is taken as 298.15K and P0 as 101.325kPa.

[0084] Various thermodynamic processes The loss is calculated using the following formula:

[0085] Ex d,k =∑EX in,k -∑EX out,k ±Q(1-T0 / T)±W

[0086] Ex in，k and Ex out,k This represents the thermodynamic processes flowing into and out of the k-th component. Q(1-T0 / T) and W represent the heat exchanged between the working fluid and the surroundings in the component and the work done by the component, respectively, and Exd,k represents the component's... loss.

[0087] according to Figure 5 Based on the location diagram and the above assumptions, the residual pressure utilization system of this integrated vortex tube utilizes the components of each component. The loss is calculated as follows:

[0088]

[0089] 3. Economic Analysis

[0090] Establish based on The cost conservation equation of the system is: The economic model is used to quantify the economic cost, and the system construction investment cost, fuel cost, operation and maintenance cost are calculated to compare the cost and benefit, and to calculate the economic benefit of the system. The economic coefficient f k , fuel cost C F,k , product cost C P , and loss cost C D，k , etc. economic indicators, through these indicators to evaluate the economic feasibility of the system, compared with the economic benefit of the pressure utilization system integrated with the vortex tube and the air flow pressure reduction system using the throttle valve.

[0091] The cost conservation equation is:∑C in,k +C Q,k +Z k =∑C out,k +C w,k , wherein C in,k , C Q,k , C W,k , C out, k represents the cost rate related to the fluid input, heat energy input, work input and fluid output of the kth component, and Z k is the cost rate of the component itself.

[0092] The cost rate C ex =C w =C q , wherein c is the unit cost, which is the unit cost, the work unit cost and the heat exchange unit cost, respectively.

[0093] In addition, the fuel cost rate C F,k and the product cost rate C P,k of the system have the following relationship: C P，k =C F,k +Z k , Z k =Z k ci +Z k om , Z k om =1.5%Z k ci , wherein Z k is the total investment cost rate of the component itself, Z k ci is the investment cost rate of the component, and Z k om is the operation cost rate of the component, zk It is the cost of components. This is the maintenance factor, and τ is the annual operating time (hours). CRF = i(i+1) n / [(i+1) n [-1] is the capital recovery factor, i is the annual interest rate, and n is the component's lifespan. Fuel cost rate C F,k and product cost ratio C P,k This is empirical data. Zk can be calculated using formulas derived from empirical data. For high-pressure cylinders, intermediate-pressure cylinders, and low-pressure cylinders, Zk is used. tur =4405W k 0.7 All other components can use Z. k =130(A) k / 0.093) 0.78 Where Ak is the heat exchange area of ​​the component [ 4 ].

[0094] and Economic coefficient f k It can be calculated using the following formula: f k =Z k / (Z k +C D,K ), can be used with f k The importance of system components is assessed, where C is the formula. D,k Represents the k-th component The loss rate can be calculated using the following formula: C D,k =c f,k *Ex D,k c f,k c is the average unit cost of fuel for the k-th component. f,k =C F,k / E f,k E f,k fuel Value. System fuel cost rate. The total system cost rate, The total fuel cost rate of the system. Total system output

[0095] according to Figure 5 Based on the location diagram and the above assumptions, the residual pressure utilization system of this integrated vortex tube utilizes the components of each component. The cost conservation equation is shown below:

[0096]

[0097] Finally, it should be noted that: the above examples are only used to illustrate the technical solutions of the present application, but not limited to them; under the idea of the present application, the technical features of the above examples or different examples can also be combined, the steps can be implemented in any order, and there are many other changes of different aspects of the present application as described above, which are not provided in details for simplicity; although the present application has been described in detail with reference to the foregoing examples, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing examples, or make equivalent replacement for part of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A heat supply extraction steam residual pressure utilization system of a combined heat and power unit, comprising: The application relates to a gas supply unit and a heating unit. The gas supply unit comprises a boiler (4), a high-pressure cylinder (1) communicated with the boiler (4), a medium-pressure cylinder (2) communicated with the high-pressure cylinder (1), and a low-pressure cylinder (3) communicated with the medium-pressure cylinder (2). The heating unit comprises a low-pressure heater (22) communicated with the low-pressure cylinder (3), a high-pressure heater (21) communicated with the high-pressure cylinder (1) and the medium-pressure cylinder (2), a condenser (6) communicated with the low-pressure heater (22) and the low-pressure cylinder (3), and a deaerator (5) communicated with the low-pressure heater (22) and the high-pressure heater (21). The application further comprises a pressure residual utilization unit, which comprises a vortex tube (10) connected with the medium-pressure cylinder (2) through a steam extraction pipe (31), and a heat network heat exchanger, wherein the hot gas flow at the hot end of the vortex tube (10) sequentially passes through a hot end pipe (34), the heat network heat exchanger (7) and a return pipe (35) into the condenser (6), the cold end of the vortex tube (10) is connected into the condenser (6) through a cold end pipe (36), and a heat user (8) is connected to the heat network heat exchanger (7) through a heat exchange pipeline (37). The vortex tube (10) has a vortex chamber, an inlet nozzle (11), a cold end and a hot end communicated with the vortex chamber, and further comprises an inlet transmission structure comprising a cylinder and a ring structure driven to rotate by the cylinder; a main inflow pipeline is connected with the inlet nozzle (11), a branch inflow pipeline is communicated with a rodless cavity of the cylinder, and a piston rod of the cylinder is drivingly connected with the ring structure. A control valve piece (16) is arranged between a valve seat (18) and a nozzle (17), and the control valve piece (16) can adjust the opening degree of the nozzle (17) and control the flow of the inflow in the inlet nozzle (11) under the driving of the ring structure; when the inflow pressure is increased, part of the inflow gas enters the rodless cavity of the cylinder through the branch inflow pipeline, the piston rod of the cylinder drives the ring structure to rotate and expands the flow area of the inlet nozzle (11) by rotating the control valve piece (16), so as to automatically adapt to the higher inlet pressure and flow.

2. The system according to claim 1, wherein the system further comprises a steam turbine (2) and a condenser (3) connected to the steam turbine (2) in series. The high-pressure cylinder (1) is a subcritical boiler, the steam temperature of the high-pressure cylinder is about 540 DEG C, and the working pressure is 15.7-19.6 Mpa.

3. The system according to claim 1, wherein the system further comprises a steam turbine (1) and a condenser (2) connected to the steam turbine (1) in series. The medium-pressure cylinder (2) is located behind the high-pressure cylinder, the exhaust pressure of the medium-pressure cylinder is ensured to be above 0.4 Mpa, the exhaust temperature is about 240 DEG C, the steam extraction pressure of the medium-pressure cylinder is 0.3-0.5 Mpa, and the temperature is 134-152 DEG C.

Images