CN201163156Y - A Combined High Temperature Air Preheater - Google Patents

Abstract

The utility model relates to a combined type high-temperature air preheater, and belongs to a heat exchange device. The combined type high-temperature air preheater consists of a radiation heat transfer section and a convection heat transfer section; a fume inlet is arranged on the front end surface of the radiation heat transfer section; a fume outlet is arranged on the rear end surface of the convection heat transfer section; a cold air inlet is arranged on the sidewall of the convection heat transfer section close to the fume outlet; a hot air outlet of the convection heat transfer section is arranged on the sidewall close to the other end of the convection heat transfer section; a high-temperature air outlet is arranged on the sidewall of the radiation heat transfer section close to the fume inlet; an air inlet of the radiation heat transfer section is arranged on the sidewall close to the other end of the radiation heat transfer section; the hot air outlet of the convection heat transfer section is connected with an air inlet pipeline of the radiation heat transfer section; the combined type high-temperature air preheater utilizes the heat transfer principle of fume in different temperature stages, combines the radiation heat transfer and the convection heat transfer into a whole, fully recycles the heat energy of fume, solves the problems that the welding between the pipeline and a tube plate is ripped under high temperature difference by heat stress caused by thermal expansion and cold contraction; and the combined type high-temperature air preheater has a simple structure, easy manufacturing, energy conservation and long service life.

Description

A Combined High Temperature Air Preheater

technical field

The utility model belongs to a heat exchange device and relates to a high-temperature air preheater designed by using the principle of heat radiation.

Background technique

The technology of using flue gas to heat air has made great progress after years of research, and various forms of air preheaters have emerged, such as heat pipe air preheaters, tubular air preheaters, and rotary air preheaters. Preheaters, finned tube air preheaters and plate air preheaters, etc., these preheaters have made great contributions to making full use of the heat of the flue gas, but they can preheat the air to above 700°C There are few equipments, mainly because the above equipment is difficult to solve the thermal stress problem caused by thermal expansion and contraction, and the welding of pipes and tube sheets often cracks due to the above stress under high temperature difference. Secondly, the equipment design is basically based on the principle of convective heat transfer, and there are almost no equipment designed using the principle of heat radiation.

Contents of the invention

The utility model aims at overcoming the above-mentioned shortcomings, and provides a combined high-temperature air preheater, which can use the flue gas higher than 1200°C to indirectly heat the air, and fully recover the heat energy of the flue gas. The main innovation is to use the flue gas at different temperature stages Based on the principle of heat transfer, the air heating part is designed into two parts: a thermal radiation heating section and a convection heating section. Specifically, it is implemented as follows: a combined high-temperature air preheater, which is characterized in that the preheater is composed of a radiation heat transfer section and a convective heat transfer section. There is a flue gas outlet on the rear end of the hot section, a cold air inlet is placed on the side wall of the convection heat transfer section close to the flue gas outlet, and a hot air outlet of the convection section is placed on the side wall near the other end of the convection heat transfer section, which is close to the flue gas outlet. The side wall of the radiation heat transfer section of the air inlet is provided with a high-temperature air outlet, and the side wall near the other end of the radiation heat transfer section is provided with an air inlet of the radiation section, and the hot air outlet of the convection section is connected with the air inlet pipe of the radiation section. When the flue gas is above 700°C, the heat transfer is dominated by heat radiation, and the heat transfer intensity of heat radiation is far greater than the intensity of convective heat transfer, and a small heat transfer area can be used to transfer a large amount of heat. The heat section is the heat transfer equipment designed by using the principle of high temperature flue gas radiation heat transfer.

The radiation heat transfer section of the present invention is a heat exchange tube structure, which is composed of a central flue gas channel and a surrounding hot air flow channel. An expansion joint with a corrugated structure is placed on the wall of the central flue gas channel to absorb thermal expansion, which solves the problem of tube-sheet type It is difficult for heat exchangers to solve the problem of thermal stress cracking of tubes and plates caused by thermal stress; there is also a guide plume in the central flue gas channel to enhance the disturbance of hot air fluid, enhance heat transfer, and reduce air short circuit. In order to prevent heat loss, an insulating castable is placed between the wall of the hot air flow channel in the radiation heat transfer section and the shell of the heat exchange cylinder. The heat transfer section can not only greatly reduce the flue gas temperature, but also greatly reduce the requirements for the heat exchange equipment in the convection section, which is the equipment that can adopt various heat-transfer structures in the convection section.

When the flue gas temperature is lower than 700°C, the heat transfer is mainly changed from heat radiation heat transfer to convection heat transfer. The convection heat transfer section of the utility model can adopt a plate heat exchanger structure or a finned tube heat exchanger structure , the structure of the shell and tube heat exchanger and the structure of the heat pipe heat exchanger. Especially the double-sided strengthened plate heat exchanger, due to its high heat transfer film coefficient, less steel consumption, small volume, high thermal efficiency, etc., compared with other heat exchangers under sub-high temperature conditions, it can save Nearly 50% of the investment. The convection heat transfer equipment can reduce the temperature of the flue gas at 700°C to below 150°C, fully recover the heat of the flue gas, and achieve the effect of energy saving.

The utility model utilizes the heat transfer principle of flue gas at different temperature stages, combines radiation heat exchange and convective heat exchange into one, fully recovers the heat of flue gas, and solves the problem of thermal stress caused by thermal expansion and contraction of pipes and pipes. The problem of plate welding cracking under high temperature difference, the heat transfer equipment is simple in structure, easy to manufacture, energy saving, and long in service life.

Description of drawings

Accompanying drawing is the structural representation of the utility model.

Detailed ways

Example 1, a combined high-temperature air preheater, the preheater is composed of a radiation heat transfer section 1 and a convective heat transfer section 2, the radiation heat transfer section 1 is a heat exchange cylinder structure, and consists of a central flue gas channel 13 and its The outer hot air flow channel 10 is formed, the wall of the flue gas channel 13 is provided with an expansion joint 6, and the flue gas channel 13 is also equipped with a guide plume 7, and the radiation heat transfer section 1 and the wall of the hot air flow channel 10 are connected with the heat exchange There is an insulating castable 9 between the shells 8; the convection heat transfer section 2 can adopt a plate heat exchanger structure, a finned tube heat exchanger structure, a tube heat exchanger structure or a heat pipe heat exchanger structure; the radiation heat transfer section 1 There is a flue gas inlet 3 on the front end, and a flue gas outlet 14 is placed on the rear end of the convection heat transfer section 2, and a cold air inlet 12 is placed on the side wall of the convection heat transfer section 2 near the flue gas outlet 14, close to the convection heat transfer The hot air outlet 11 of the convection section is installed on the side wall at the other end of the section 2, and the high-temperature air outlet 4 is installed on the side wall of the radiation heat transfer section 1 near the flue gas inlet 3, and the hot air outlet 4 is installed on the side wall near the other end of the radiation heat transfer section 1. The air inlet 5 of the radiation section is provided, and the hot air outlet 11 of the convection section is connected with the air inlet 5 of the radiation section.

Example 2, referring to Example 1, the expansion joint 6 on the wall of the flue gas passage 13 is a corrugated expansion joint, and the convection heat transfer section 2 adopts a double-plate heat exchanger.

The cold air enters the heat exchanger from the cold air inlet 12, and in the convection heat transfer section 2, the air is heated to above 600°C by using the convection heat transfer principle, and then enters the radiation heat transfer section 1, and continues to use the heat radiation heat transfer principle of the air Continue to be heated to above 800°C and supply to the user; the flue gas above 1200°C enters the air heater from the flue gas inlet 3, is cooled to about 850°C in the radiation section and enters the convection section, and continues to be cooled by air below 150°C , to discharge the device.

Claims (8)

1. A combined high-temperature air preheater, characterized in that the preheater is composed of a radiation heat transfer section and a convection heat transfer section, a flue gas inlet is arranged on the front end of the radiation heat transfer section, and a flue gas inlet is arranged on the rear end surface of the convection heat transfer section There is a flue gas outlet, a cold air inlet is placed on the side wall of the convection heat transfer section near the flue gas outlet, a hot air outlet of the convection section is placed on the side wall near the other end of the convection heat transfer section, and a radiation transfer section near the flue gas inlet A high-temperature air outlet is arranged on the side wall of the heat section, and an air inlet of the radiation section is arranged on the side wall near the other end of the radiation heat transfer section, and the hot air outlet of the convection section is connected with the air inlet pipe of the radiation section. 2. The combined high-temperature air preheater according to claim 1, characterized in that the radiation heat transfer section is a heat exchange cylinder structure, which is composed of a central flue gas channel and a surrounding hot air channel. 3. The combined high-temperature air preheater according to claim 2, characterized in that an expansion joint is placed on the wall of the central flue gas passage. 4. The combined high-temperature air preheater according to claim 3, characterized in that it is an expansion joint with a corrugated structure. 5. The combined high-temperature air preheater according to any one of claims 2, 3, and 4, characterized in that guide plumes are built in the central flue gas channel. 6. The combined high-temperature air preheater according to claim 2, characterized in that an insulating castable is interposed between the tube wall of the hot air passage in the radiation heat transfer section and the shell of the heat exchange tube. 7. The combined high-temperature air preheater according to claim 1, characterized in that the convective heat transfer section adopts a plate heat exchanger structure or a finned tube heat exchanger structure or a tube heat exchanger structure or a heat pipe heat exchanger structure. 8. The combined high-temperature air preheater according to claim 7, characterized in that the convection heat transfer section adopts a double-panel heat exchanger.

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