CN106247808B - Heating-furnace cogeneration system with vertical lower resistance heat pipe - Google Patents

Abstract

The invention discloses a heating furnace waste heat power generation system with vertical low-resistance heat pipes, which includes a heating furnace, a waste heat recovery device, a superheater, a steam turbine, a generator, a condenser and a plurality of The first heat pipe, the evaporation end of the first heat pipe is connected to the flue of the heating furnace, the condensation end of the first heat pipe is connected to the waste heat recovery device, the waste heat recovery device is provided with working fluid, and the outlet flow channel of the working medium is connected to the superheater The inlet and the outlet of the superheater are connected to the steam turbine, the output shaft of the steam turbine is connected to the generator, the outlet of the working medium channel of the steam turbine is connected to the inlet of the condenser, and the outlet pipe of the condenser is provided with a pump, which is connected to the waste heat recovery device. The working fluid inlet channel; the outer surface of the first heat pipe is equipped with high-density multi-layer and multi-row linear bent heat exchange elements. Thus, the utilization efficiency of the waste heat of the heating furnace is greatly improved through the first heat pipe, the steam turbine and the generator, which saves energy and is environmentally friendly.

Description

Heating furnace waste heat power generation system with vertical low-resistance heat pipes

technical field

The invention relates to the field of recovery and utilization of waste heat and waste energy, in particular to a heating furnace waste heat power generation system with vertical low-resistance heat pipes.

Background technique

As a major energy consumer, steel rolling heating furnaces in iron and steel enterprises directly affect the production costs of enterprises. Generally, as a heating equipment, the thermal efficiency of a heating furnace is generally about 30%, and the energy consumption is high and the energy utilization level is low, resulting in a large amount of energy waste. Therefore, recovering the waste heat of the heating furnace has both good economic benefits and certain environmental benefits.

At present, most iron and steel enterprises use vaporization cooling walking beam heating furnaces. The general fuel is mixed gas, and the smoke exhaust method is natural smoke exhaust. The exhaust gas temperature is generally around 900 degrees Celsius. However, the waste heat recovery efficiency in the prior art is generally low.

Contents of the invention

In order to solve the above problems, the present invention provides a heating furnace waste heat power generation system with vertical low-resistance heat pipes.

According to one aspect of the present invention, a heating furnace waste heat power generation system with vertical low-resistance heat pipes is provided, including a heating furnace, a waste heat recovery device, a superheater, a steam turbine, a generator, a condenser, and a flue gas at the tail of the heating furnace. A plurality of first heat pipes are arranged in the airflow direction, the evaporation end of the first heat pipe is connected with the flue of the heating furnace, the condensation end of the first heat pipe is connected to the waste heat recovery device, the waste heat recovery device is provided with working fluid, and the waste heat recovery device is provided with The working medium inlet flow channel and the working medium outlet flow channel, the working medium outlet flow channel is connected to the inlet of the superheater, the outlet of the superheater is connected to the steam turbine, the output shaft of the steam turbine is connected to the generator, and the steam turbine is provided with a working medium channel, the steam turbine The outlet of the working medium channel is connected to the inlet of the condenser, the outlet pipe of the condenser is provided with a pump, and the pump is connected to the working medium inlet flow channel of the waste heat recovery device;

The outer surfaces of the evaporating end and the condensing end of the first heat pipe are equipped with high-density multi-layer and multi-row linear bending heat exchange elements. The linear bending heat exchange elements are bent four times by a metal wire to form the first bend. part, the second bent part, the third bent part, the fourth bent part and the fifth bent part, the linear bent heat exchange element passes through the first bent part and the fifth bent part and the first heat pipe External surface welding;

The condenser includes the second heat pipe, the exhaust steam cavity of the steam turbine and the cooling water cavity. The exhaust steam cavity of the steam turbine and the cooling water cavity are separated by a sealed partition. The evaporation end of the second heat pipe is located in the exhaust steam cavity of the steam turbine, and the condensation end of the second heat pipe Located in the cooling water chamber.

The beneficial effect is that the heating furnace discharges high-temperature flue gas, the high-temperature flue gas passes through the evaporation end of the first heat pipe, the evaporation end of the first heat pipe starts after being heated by the high-temperature flue gas, the first heat pipe enters the working state, and starts to transfer to the condensation end. The condensing end of the first heat pipe is immersed in the working fluid inside the waste heat recovery device, the condensing end of the first heat pipe provides heat to the working fluid, and the heated working fluid is sent to the superheater. After the superheater is heated, a phase change occurs, from a high-temperature liquid to a high-temperature and high-pressure gaseous state, thereby driving the steam turbine to work. The output shaft of the steam turbine is connected to the generator, thereby driving the generator to generate electricity. The temperature and pressure of the gaseous working medium will decrease, but it still has a relatively high temperature and becomes a high-temperature and low-pressure gaseous working medium. In order to obtain a high pressure difference at both ends of the steam turbine, the outlet of the working medium channel of the steam turbine is connected with the inlet of the condenser. The strong suction of the vacuum inside the condenser can make the steam wash the blades of the steam turbine at the highest speed to maximize the enthalpy drop of the steam, which can greatly increase the efficiency of the steam turbine, thereby increasing the power generation of the generator. On the outlet pipe of the condenser A pump is provided, and the pump is connected to the working medium inlet channel of the waste heat recovery device, and the liquid working medium is transported to the waste heat recovery device through the pump, so that the working medium can be recycled and the whole system can be continuously used; considering the high temperature discharged from the heating furnace The flue gas and the working medium in the first heat pipe have different heat transfer coefficients to the tube wall. The heat transfer coefficient of the working medium in the first heat pipe is generally very high, while the flue gas flowing outside the evaporation end of the first heat pipe has a heat transfer coefficient of The coefficient is generally low, and the difference between the two is dozens of times or even hundreds of times. In this way, the heat transfer coefficient on the flue gas side is low, and the heat transfer capacity is low, which limits the improvement of heat transfer. In the present invention, the outer surface of the first heat pipe is provided with high-density The linear bent heat exchange element is simple to manufacture, and the linear bent heat exchange element is welded to the first heat pipe through the first bending part and the fifth bending part, so that the linear bending heat exchange The connection between the part and the first heat pipe is more stable, the linear bent heat exchange part is not easy to loosen from the first heat pipe, and the high-density linear bent heat exchange part greatly increases the actual heat transfer area of the first heat pipe. Solving the "bottleneck" of flue gas side heat exchange, the heat transfer effect of the first heat pipe will be greatly increased, which can greatly increase the heat transfer capacity of the first heat pipe, further improve the waste heat utilization efficiency of the present invention, save energy, and be environmentally friendly; the superheater comes out The high-temperature steam will lose part of the energy in the process of driving the steam turbine to do work, but the steam turbine only uses a small part of the high-temperature and high-pressure steam, and the exhaust steam entering the condenser still contains a large amount of heat energy. The contained energy can better save energy, so that energy can be fully utilized. In the present invention, the condenser adopts a heat pipe condenser, and the heat pipe has a very high thermal conductivity, which is a near superconductor, which will greatly improve The utilization rate of exhaust steam heat energy, in the present invention, the evaporation end of the second heat pipe is located in the exhaust steam chamber of the steam turbine, and the exhaust steam of the steam turbine enters the exhaust steam chamber of the steam turbine to heat the evaporation end of the second heat pipe, and the exhaust steam becomes into a liquid working medium, which is transported by the pump to the waste heat recovery device for recycling, while the second The evaporation end of the second heat pipe starts after being heated by exhaust steam, the second heat pipe enters the working state, and starts to transfer heat to the condensation end, the condensation end of the second heat pipe is immersed in the cooling water in the cooling water cavity, The cooling water provides heat, and the heated cooling water flows to a predetermined position according to actual needs, thus further improving the waste heat utilization rate of the entire system.

In some embodiments, the first bent part and the fifth bent part are welded longitudinally along the first heat pipe, and a stainless steel ring is welded on the third bent part of each layer of linear bent heat exchange elements, and the stainless steel ring will be connected to the same The layered linear bent heat exchange elements are hooped.

The beneficial effect is that a stainless steel ring is welded on the third bending part of each layer of linear bending heat exchange parts, and the stainless steel rings hug the linear bending heat transfer parts of the same layer, and each layer of stainless steel rings increases again. The heat transfer area of each layer is increased, the heat transfer effect is further enhanced, the heat transfer efficiency is higher, and the heat transfer is more ideal. At the same time, the stainless steel ring also plays a role of a stable connection to the linear bending heat transfer parts of the same layer.

In some embodiments, the outer surfaces of the evaporating end and the condensing end of the second heat pipe are equipped with high-density multi-layer and multi-row linear bent heat exchange elements, and the linear bent heat exchange elements are made of a metal wire bent four times Bending to form the first bending part, the second bending part, the third bending part, the fourth bending part and the fifth bending part, and the linear bending heat exchange element passes through the first bending part and the fifth bending part The part is welded with the outer surface of the second heat pipe.

Its beneficial effect is that the high-density linear bending heat exchange parts will greatly increase the actual heat transfer area of the second heat pipe, the heat transfer effect of the second heat pipe will be greatly increased, and the heat transfer amount of the second heat pipe can be greatly improved. Improve waste heat utilization efficiency of the present invention.

In some embodiments, the second heat pipe is specifically a potassium-stainless steel heat pipe, and the working medium inside it is liquid potassium.

The beneficial effect is that the temperature of the exhaust steam from the steam turbine is lower than that of the high-temperature steam from the superheater, and the potassium-stainless steel heat pipe has a high heat exchange rate, which can meet the use requirements of the condenser environment.

In some embodiments, the working medium in the waste heat recovery device is specifically an organic zeotropic mixture working medium.

The beneficial effect is that the organic non-azeotropic mixture has stable chemical properties and excellent thermophysical properties, which can reduce irreversible losses in heat transfer and improve system efficiency.

Description of drawings

Fig. 1 is a schematic structural view of a heating furnace waste heat power generation system with vertical low-resistance heat pipes according to an embodiment of the present invention;

Fig. 2 is a schematic diagram of the surface of the first heat pipe shown in Fig. 1;

Fig. 3 is the schematic diagram of the surface of the second heat pipe shown in Fig. 1;

Fig. 4 is a schematic structural diagram of a linear bent heat exchange element.

Detailed ways

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

1 to 4 schematically show a heating furnace waste heat power generation system with vertical low-resistance heat pipes according to an embodiment of the present invention. As shown in the figure, the heating furnace waste heat power generation system with vertical low-resistance heat pipes includes a heating furnace 1, a waste heat recovery device 2, a superheater 5, a steam turbine 6, a generator 7, a condenser 8 and at the tail of the heating furnace 1 along A plurality of first heat pipes 3 are arranged in the flow direction of the flue gas. The evaporation end of the first heat pipe 3 is connected to the flue of the heating furnace 1, and the condensation end of the first heat pipe 3 is connected to the waste heat recovery device 2. The waste heat recovery device 2 is provided with a working fluid inlet flow channel 201 and a working medium outlet flow channel 202, the working medium outlet flow channel 202 is connected to the inlet of the superheater 5, the outlet of the superheater 5 is connected to the steam turbine 6, and the output of the steam turbine 6 The shaft is connected to the generator 7, the steam turbine 6 is provided with a working medium channel, the outlet of the working medium channel of the steam turbine 6 is connected to the inlet of the condenser 8, and the outlet pipe of the condenser 8 is provided with a pump 9, which is connected to the waste heat recovery The working fluid inlet channel 201 of the device 2;

The outer surfaces of the evaporating end and the condensing end of the first heat pipe 3 are equipped with high-density multi-layer and multi-row linear bent heat exchange elements 4, and the linear bent heat exchange elements 4 are formed by bending a metal wire four times. A bent part 401, a second bent part 402, a third bent part 403, a fourth bent part 404 and a fifth bent part 405, the linear bent heat exchange element 4 passes through the first bent part 401 and The fifth bent portion 405 is welded to the outer surface of the first heat pipe 3;

The condenser 8 includes a second heat pipe 801, a steam turbine exhaust chamber 802 and a cooling water chamber 803, the steam turbine exhaust chamber 802 and the cooling water chamber 803 are separated by a sealing partition 804, and the evaporation end of the second heat pipe 801 is located in the steam turbine exhaust chamber In 802 , the condensation end of the second heat pipe 801 is located in the cooling water cavity 803 .

Its beneficial effect is that the heating furnace 1 discharges high-temperature flue gas, the high-temperature flue gas passes through the evaporation end of the first heat pipe 3, and the evaporation end of the first heat pipe 3 starts after being heated by the high-temperature flue gas, and the first heat pipe 3 enters the working state and starts Transfer heat to the condensing end, the condensing end of the first heat pipe 3 is immersed in the working fluid inside the waste heat recovery device 2, the condensing end of the first heat pipe 3 provides heat to the working fluid, and the heated working fluid is transported to the superheater 5, Due to the low boiling point of the working fluid, a phase change occurs after being heated by the superheater 5, from a high-temperature liquid state to a high-temperature and high-pressure gas state, thereby driving the steam turbine 6 to work, and the output shaft of the steam turbine 6 is connected to the generator 7, thereby driving the generator 7 to generate electricity After the high-temperature and high-pressure gaseous working medium works to push the steam turbine 6 to work, the temperature and pressure of the gaseous working medium will decrease, but it still has a relatively high temperature and becomes a high-temperature and low-pressure gaseous working medium. In order to obtain high pressure at both ends of the steam turbine 6 Poor, the outlet of the working medium channel of the steam turbine 6 is connected with the inlet of the condenser 8, and the strong suction force of the internal vacuum of the condenser 8 can make the steam wash the blades of the steam turbine 6 at the highest speed to maximize the steam enthalpy drop, which can greatly increase The efficiency of the steam turbine 6, thereby increasing the power generation of the generator 7, the outlet pipe of the condenser 8 is provided with a pump 9, the pump 9 is connected to the working medium inlet flow channel 201 of the waste heat recovery device 2, and the liquid working medium is transported through the pump 9 To the waste heat recovery device 2, so that the working medium can be recycled, so that the whole system can be continuously recycled; considering that the high-temperature flue gas discharged from the heating furnace 1 is different from the heat transfer coefficient of the working medium in the first heat pipe 3 to the pipe wall, the second The heat transfer coefficient of the working medium in the first heat pipe 3 is generally very high, while the heat transfer coefficient of the flue gas flowing outside the evaporation end of the first heat pipe 3 is generally low, and the difference between the two is dozens of times or even hundreds of times. The side heat transfer coefficient is low and the heat transfer capacity is low, which limits the improvement of heat transfer. In the present invention, the outer surface of the first heat pipe 3 is provided with high-density linear bent heat exchange elements 4, and the linear bent heat exchange elements 4 The production is simple, and the linear bent heat exchange element 4 is welded to the first heat pipe 3 through the first bending part 401 and the fifth bending part 405, so that the connection between the linear bent heat exchange element 4 and the first heat pipe 3 More stable, the linear bent heat exchange element 4 is not easy to loose from the first heat pipe 3, the high-density linear bent heat exchange element 4 will greatly increase the actual heat transfer area of the first heat pipe 3, and solve the problem of flue gas side The "bottleneck" of heat exchange, the heat transfer effect of the first heat pipe 3 will be greatly increased, which can greatly increase the heat transfer capacity of the first heat pipe 3, further improve the waste heat utilization efficiency of the present invention, save energy, and be environmentally friendly; in addition, the superheater 5 comes out The high-temperature steam will lose part of its energy in the process of pushing the steam turbine 6 to do work, but the steam turbine 6 only uses a small part of the high-temperature and high-pressure steam, and the exhaust steam entering the condenser 8 still contains a large amount of heat energy, so it is good to use the exhaust steam. The energy contained in the steam can better save energy, so that the energy can be fully utilized. In the present invention, the condenser 8 adopts a heat pipe condenser, and the heat pipe has a very high thermal conductivity, which is a near superconductor , will greatly improve the utilization rate of exhaust steam heat energy. In the present invention, the evaporation end of the second heat pipe 801 is located at the steam turbine In the exhaust steam chamber 802 of the turbine, the exhaust steam of the steam turbine enters the exhaust steam chamber 802 of the steam turbine to heat the evaporation end of the second heat pipe 801, and the exhaust steam passes through the condenser 8 and becomes a liquid working medium, which is transported to the waste heat recovery device 2 by the pump 9 cyclic use, and the evaporation end of the second heat pipe 801 starts after being heated by exhaust steam, the second heat pipe 801 enters the working state, and starts to transfer heat to the condensation end, and the condensation end of the second heat pipe 801 is immersed in the cooling water cavity 803 for cooling In the water, the condensation end of the second heat pipe 801 provides heat to the cooling water, and the heated cooling water flows to a predetermined position according to actual needs, thus further improving the waste heat utilization rate of the whole system.

Preferably, the first bent part 401 and the fifth bent part 405 are welded longitudinally along the first heat pipe 3, and the third bent part 403 of each layer of linear bent heat exchange element 4 is welded with a stainless steel ring 406, stainless steel The ring 406 hugs the linear bent heat exchange elements 4 of the same layer.

The beneficial effect is that a stainless steel ring 406 is welded on the third bending part 403 of each layer of the linear bent heat exchange element 4, and the stainless steel ring 406 hugs the linear bent heat exchange element 4 of the same layer, and each layer The stainless steel ring 406 increases the heat transfer area of each layer again, the heat transfer effect is further enhanced, the heat transfer efficiency is higher, and the heat transfer is more ideal. The role of a solid connection.

Preferably, the outer surfaces of the evaporating end and the condensing end of the second heat pipe 801 are equipped with high-density multi-layer and multi-row linear bent heat exchange elements 4, and the linear bent heat exchange elements 4 are folded four times by a metal wire. Bending to form the first bending part 401, the second bending part 402, the third bending part 403, the fourth bending part 404 and the fifth bending part 405, the linear bending heat exchange element 4 passes through the first bending The portion 401 and the fifth bent portion 405 are welded to the outer surface of the second heat pipe 803 .

Its beneficial effect is that the high-density linear bending heat exchange element 4 will greatly increase the actual heat transfer area of the second heat pipe 801, the heat transfer effect of the second heat pipe 801 will be greatly increased, and the heat transfer efficiency of the second heat pipe 801 can be greatly improved. heat transfer, further improving the waste heat utilization efficiency of the present invention.

Preferably, the first heat pipe 3 is specifically a lithium-tungsten heat pipe, and the working medium inside it is liquid lithium.

The beneficial effect is that the lithium-tungsten heat pipe is a high-temperature heat pipe, which is very suitable for the use environment of the present invention, especially lithium has a high axial heat transfer density, which can further improve the waste heat utilization efficiency of the present invention.

Preferably, the second heat pipe 801 is specifically a potassium-stainless steel heat pipe, and the working medium inside it is liquid potassium.

The beneficial effect is that the temperature of the exhaust steam from the steam turbine 6 is lower than that of the high-temperature steam from the superheater, and the potassium-stainless steel heat pipe has a high heat exchange rate, which can meet the use requirements of the condenser 8 environment.

Preferably, the working fluid in the waste heat recovery device 2 is specifically an organic zeotropic mixed working fluid.

The beneficial effect is that the organic non-azeotropic mixture has stable chemical properties and excellent thermophysical properties, which can reduce irreversible losses in heat transfer and improve system efficiency.

What have been described above are only some embodiments of the present invention. For those skilled in the art, without departing from the inventive concept of the present invention, several modifications and improvements can be made, and these all belong to the protection scope of the present invention.

Claims (4)

1. A heating furnace waste heat power generation system with vertical low-resistance heat pipes, characterized in that it includes a heating furnace (1), a waste heat recovery device (2), a superheater (5), a steam turbine (6), a generator (7), a condenser vaporizer (8) and a plurality of first heat pipes (3) arranged along the flue gas flow direction at the tail of the heating furnace (1), the evaporation end of the first heat pipes (3) communicates with the flue of the heating furnace (1), The condensation end of the first heat pipe (3) is connected to the waste heat recovery device (2), the waste heat recovery device (2) is provided with a working fluid, and the waste heat recovery device (2) is provided with a working fluid inlet flow channel (201 ) and working fluid outlet channel (202), the working fluid outlet channel (202) is connected to the inlet of the superheater (5), the outlet of the superheater (5) is connected to the steam turbine (6), and the steam turbine The output shaft of (6) links to each other with generator (7), and described steam turbine (6) is provided with working medium passage, and the outlet of working medium passage of described steam turbine (6) links to each other with condenser (8) inlet, and described A pump (9) is provided on the outlet pipeline of the condenser (8), and the pump (9) is connected to the working medium inlet flow channel (201) of the waste heat recovery device (2); The outer surfaces of the evaporating end and the condensing end of the first heat pipe (3) are equipped with high-density multi-layer and multi-row linear bent heat exchange elements (4), and the linear bent heat exchange elements (4) are composed of a A metal wire is bent four times to form a first bending part (401), a second bending part (402), a third bending part (403), a fourth bending part (404) and a fifth bending part (405), the linear bent heat exchange element (4) is welded to the outer surface of the first heat pipe (3) through the first bent part (401) and the fifth bent part (405); The condenser (8) includes a second heat pipe (801), a steam turbine exhaust chamber (802) and a cooling water chamber (803), and the steam turbine exhaust chamber (802) and the cooling water chamber (803) pass through a sealed partition The plate (804) is separated, the evaporation end of the second heat pipe (801) is located in the exhaust chamber (802) of the steam turbine, and the condensation end of the second heat pipe (801) is located in the cooling water chamber (803), The first bending part (401) and the fifth bending part (405) are welded longitudinally along the first heat pipe (3), and the third bending part of each layer of the linear bending heat exchange element (4) A stainless steel ring (406) is welded on the bent part (403), and the stainless steel ring (406) hugs the linear bent heat exchange element (4) of the same layer. 2. The heating furnace waste heat power generation system with vertical low-resistance heat pipes according to claim 1, characterized in that, the outer surfaces of the evaporation end and the condensation end of the second heat pipe (801) are equipped with high-density multi-layer and multi-row A linear bent heat exchange element (4), the linear bent heat exchange element (4) is bent four times by a metal wire to form a first bending part (401), a second bending part (402 ), the third bending part (403), the fourth bending part (404) and the fifth bending part (405), the linear bending heat exchange element (4) passes through the first bending part (401) And the fifth bending part (405) is welded with the outer surface of the second heat pipe (801). 3. The heating furnace waste heat power generation system with vertical low-resistance heat pipes according to claim 1, wherein the second heat pipe (801) is specifically a potassium-stainless steel heat pipe, and the working medium inside it is liquid potassium. 4. The heating furnace waste heat power generation system with vertical low-resistance heat pipes according to claim 1, characterized in that, the working medium in the waste heat recovery device (2) is specifically an organic zeotropic mixed working medium.