Flue gas waste heat utilization boiler

Abstract

The utility model relates to the technical field of waste heat boilers, in particular to a flue gas waste heat utilization boiler. A flue gas inlet and a flue gas outlet are formed in the two ends of the flue gas channel respectively, the ends of the flue gas inlet and the flue gas outlet extend out of the boiler body, the flue gas inlet communicates with a flue gas discharge outlet of upstream equipment, the water inlet end of the economizer communicates with an external water source through a first branch pipeline, and the water outlet end of the economizer communicates with the boiler barrel through a second branch pipeline. A liquid outlet pipe and an air inlet pipe are communicated with the boiler barrel, the liquid outlet pipe is communicated with the liquid inlet end of the convection bank, the air inlet pipe is communicated with the air outlet end of the convection bank, and the liquid inlet end of the convection bank is lower than the air outlet end of the convection bank. The superheater arranged on the boiler barrel exhaust pipe is used for reheating part of steam in the boiler barrel and then discharging the reheated steam to the side, close to the smoke inlet, of the smoke channel to heat the boiler together with smoke, the temperature in the smoke channel is increased, more steam is provided for the boiler barrel, and the use requirement of a user can be met.

Description

Technical Field

[0001] This utility model relates to the field of waste heat boiler technology, and in particular to a flue gas waste heat utilization boiler. Background Technology

[0002] Waste heat boilers are devices that use high-temperature flue gas generated by upstream equipment to exchange heat with a working fluid to produce steam or hot water. The temperature of the high-temperature flue gas discharged from the upstream equipment is generally between 170℃ and 300℃. However, the operating time of most upstream equipment will decrease significantly at the beginning and end of the operation period, resulting in the high-temperature flue gas generated being insufficient to meet the requirements of the waste heat boiler. Consequently, the steam or hot water produced by the waste heat boiler cannot meet the user's needs. Summary of the Invention

[0003] To address the problem that the high-temperature flue gas generated by the upstream equipment of existing waste heat boilers is insufficient to meet the requirements of the waste heat boiler when the operating time is insufficient, this utility model proposes a flue gas waste heat utilization boiler. By installing a superheater on the boiler drum exhaust pipe, a portion of the steam in the boiler drum is reheated and discharged to the side of the flue gas passage near the flue gas inlet, where it heats the boiler together with the flue gas, thereby increasing the temperature in the flue gas passage and providing more steam to the boiler drum to meet the user's needs.

[0004] To achieve the above objectives, the technical solution of this utility model is as follows:

[0005] A flue gas waste heat recovery boiler includes a boiler body, a flue gas passage disposed within the boiler body, and a boiler drum disposed at the upper end of the boiler body. The flue gas passage has a flue gas inlet and a flue gas outlet at its two ends, both of which extend out of the boiler body. The flue gas inlet is connected to the flue gas discharge port of an upstream device. A superheater, a convection tube bundle, and an economizer are sequentially arranged within the flue gas passage along the flue gas flow direction. The economizer's inlet is connected to an external water source via a first branch pipe, and its outlet is connected to the boiler drum via a second branch pipe. The boiler drum has a liquid outlet pipe and an air inlet pipe connected to it. The liquid outlet pipe is connected to the liquid inlet of the convection tube bundle, and the air inlet pipe is connected to the air outlet of the convection tube bundle. The liquid inlet of the convection tube bundle is lower than its air outlet. The boiler drum also has an exhaust pipe, and the superheater is mounted on the exhaust pipe. The end of the exhaust pipe extends into the flue gas passage and is located on the side of the flue gas passage closest to the flue gas inlet.

[0006] Preferably, the flue gas passage is in the shape of an inverted "U" within the boiler body. This increases the travel distance of the flue gas within the boiler body, improving the residence time of the flue gas and the utilization efficiency of waste heat.

[0007] Preferably, the superheater includes a low-temperature superheater and a high-temperature superheater, wherein the high-temperature superheater is located between the low-temperature superheater and the outlet end of the exhaust pipe.

[0008] Preferably, there are multiple economizers, and the inlet and outlet of two adjacent economizers are connected by a pipe.

[0009] Preferably, there are multiple convection tube bundles, with the liquid inlet end of each convection tube bundle connected to the liquid outlet pipe and the gas outlet end of each convection tube bundle connected to the gas inlet pipe. The multiple convection tube bundles are evenly distributed in the flue gas channel.

[0010] Preferably, a water-cooled wall is fixed inside the flue gas passage to better absorb heat from the flue gas.

[0011] The beneficial effects of this utility model through the above technical solution are as follows: This utility model connects an external water source to the boiler drum through an economizer. At the same time, the economizer is equipped with a flue gas inlet, and the water inside it will receive some heat. The boiler drum is also equipped with a liquid outlet pipe, which uses the height difference to discharge the water in the boiler drum to the convection tube bundle. The convection tube bundle forms a steam-water mixture under the heating effect of the flue gas, and then returns to the boiler drum through the air inlet pipe. When the high-temperature flue gas generated by the upstream equipment of the waste heat boiler is insufficient, the steam in the boiler drum is transported to the superheater through the exhaust pipe in the boiler drum for reheating and then introduced into the flue gas channel to heat the convection tube bundle and the economizer, making up for the problem of insufficient high-temperature flue gas, and providing more steam to the boiler drum, thereby meeting the user's needs. Attached Figure Description

[0012] Figure 1 This is a schematic diagram of the structure of a flue gas waste heat utilization boiler according to the present invention;

[0013] Figure 2 This is a schematic diagram of the connection structure between the boiler drum and multiple economizers of a flue gas waste heat utilization boiler according to this utility model.

[0014] Figure 3 This is a schematic diagram of the connection structure between the boiler drum and multiple convection tube bundles of a flue gas waste heat utilization boiler according to this utility model.

[0015] Figure 4 This is a schematic diagram of the connection structure between the boiler drum and the superheater of a flue gas waste heat utilization boiler according to this utility model.

[0016] In the attached diagram, the following numbers are used: 1 is the boiler body, 2 is the flue gas passage, 3 is the boiler drum, 4 is the flue gas inlet, 5 is the flue gas outlet, 6 is the superheater, 7 is the convection tube bundle, 8 is the economizer, 9 is the first branch pipe, 10 is the second branch pipe, 11 is the liquid outlet pipe, 12 is the air inlet pipe, 13 is the exhaust pipe, and 14 is the water-cooled wall. Detailed Implementation

[0017] The present invention will be further described below with reference to the accompanying drawings and specific embodiments:

[0018] like Figures 1-4 As shown, this embodiment provides a flue gas waste heat utilization boiler, including a boiler body 1, a flue gas passage 2 welded and fixed inside the boiler body 1, and a boiler drum 3 welded to the upper end of the boiler body 1. The boiler drum 3 is horizontally placed on the boiler body 1. The flue gas passage 2 has a flue gas inlet 4 and a flue gas outlet 5 at its two ends, respectively. The ends of both the flue gas inlet 4 and the flue gas outlet 5 extend out of the boiler body 1. The flue gas inlet 4 is connected to the flue gas discharge port of upstream equipment. The boiler drum 3 is positioned higher than all positions of the flue gas passage 2. The flue gas passage 2 is in an inverted "U" shape inside the boiler body 1 to increase the travel distance of the flue gas within the flue gas passage 2. A water-cooled wall 14 is fixed inside the flue gas passage 2.

[0019] The flue gas passage 2 is provided with a superheater 6, a convection tube bundle 7 and an economizer 8 arranged sequentially along the flue gas flow direction. The water inlet of the economizer 8 is connected to an external water source through a first branch pipe 9, and the water outlet of the economizer 8 is connected to the boiler drum 3 through a second branch pipe 10. The external water source is transported to the economizer 8 by the power of the water pump and then enters the boiler drum 3. In this embodiment, there are four economizers 8, and the water inlet and outlet of two adjacent economizers 8 are connected by a pipe.

[0020] The boiler drum 3 is connected to a liquid outlet pipe 11 and an air inlet pipe 12. The liquid outlet pipe 11 is connected to the liquid inlet end of the convection tube bundle 7, and the air inlet pipe 12 is connected to the air outlet end of the convection tube bundle 7. The liquid inlet end of the convection tube bundle 7 is lower than the air outlet end of the convection tube bundle 7. The boiler drum 3 is divided into upper and lower parts. The upper part is used to store steam and the lower part is used to store liquid water. The liquid outlet pipe 11 is connected to the lower part and transports the liquid water into the convection tube bundle 7 under the action of gravity. During the heating process of the flue gas, the water in the convection tube bundle 7 boils and evaporates into water vapor. The air outlet end of the convection tube bundle 7 is higher than the liquid level in the convection tube bundle 7. The water vapor moves upward to the upper part of the boiler drum 3 through the air inlet pipe 12 connected to the air outlet end of the convection tube bundle 7.

[0021] The boiler drum 3 is equipped with a liquid level sensor to detect the water level inside the boiler drum 3. When the liquid water is insufficient, it is replenished by a water pump. When there is enough liquid water, the water pump can be turned off.

[0022] The boiler drum 3 is also equipped with an exhaust pipe 13. The connection between the exhaust pipe 13 and the boiler drum 3 is located in the upper half of the boiler drum 3. The superheater 6 is installed on the exhaust pipe 13. The end of the exhaust pipe 13 extends into the flue gas passage 2 and is located on the side of the flue gas passage 2 near the flue gas inlet 4. The superheater 6 includes a low-temperature superheater and a high-temperature superheater. The high-temperature superheater is located between the low-temperature superheater and the outlet end of the exhaust pipe 13. The exhaust pipe 13 transports part of the steam in the boiler drum 3 into the flue gas passage 2. During this process, the superheater 6 heats this part of the steam and discharges it into the flue gas passage 2. Together with the high-temperature flue gas generated by the upstream equipment of the waste heat boiler, it heats the flue gas passage 2, causing more water vapor to be transported into the boiler drum 3 from the convection tube bundle 7.

[0023] In this embodiment, there are multiple convection tube bundles 7, which are evenly arranged in the flue gas channel 2. The liquid inlet end of each convection tube bundle 7 is connected to the liquid outlet pipe 11, and the gas outlet end of each convection tube bundle 7 is connected to the gas inlet pipe 12.

[0024] When the high-temperature flue gas generated by the upstream equipment of the waste heat boiler is delivered to the flue gas passage 2, the water pump is turned on and the water is pumped to the economizer 8 through the first branch pipe 9 and then into the boiler drum 3. The economizer 8 is located in the flue gas passage 2, where the flue gas heats it. Then, the liquid outlet pipe 11 on the boiler drum 3 sends the water to the convection tube bundle 7 in the flue gas passage 2. The flue gas heats the convection tube bundle 7, and the liquid in the convection tube bundle 7 vaporizes after reaching the boiling point. It moves upward to the upper part of the boiler drum 3 through the air inlet pipe 12 connected to the air outlet end of the convection tube bundle 7. Some of the water vapor in the boiler drum 3 enters the flue gas passage 2 through the exhaust pipe 13. The superheater 6 on the exhaust pipe 13 heats this part of the steam and then discharges it into the flue gas passage 2. Together with the high-temperature flue gas generated by the upstream equipment of the waste heat boiler, it heats the flue gas passage 2, causing more water vapor to be delivered to the boiler drum 3 from the convection tube bundle 7.

[0025] The embodiments described above are merely preferred embodiments of this utility model and are not intended to limit the scope of implementation of this utility model. Therefore, all equivalent changes or modifications made to the structure, features and principles described in the patent claims of this utility model should be included within the scope of the patent application of this utility model.

Claims

1. A flue gas waste heat utilization boiler, characterized in that, It includes a boiler body (1), a flue gas passage (2) set inside the boiler body (1) and a boiler drum (3) set at the upper end of the boiler body (1). The flue gas passage (2) is provided with a flue gas inlet (4) and a flue gas outlet (5) at both ends. The ends of the flue gas inlet (4) and the flue gas outlet (5) extend out of the boiler body (1). The flue gas inlet (4) is connected to the flue gas discharge port of the upstream equipment. The flue gas passage (2) is arranged in sequence along the flue gas flow direction, including a superheater (6), a convection tube bundle (7), and an economizer (8). The water inlet of the economizer (8) is connected to an external water source through a first branch pipe (9), and the water outlet of the economizer (8) is connected to the boiler drum (3) through a second branch pipe (10). The boiler drum (3) is connected to a liquid outlet pipe (11) and an air inlet pipe (12). The liquid outlet pipe (11) is connected to the liquid inlet of the convection tube bundle (7), and the air inlet pipe (12) is connected to the air outlet of the convection tube bundle (7). The liquid inlet of the convection tube bundle (7) is connected to the air outlet of the convection tube bundle (7). The boiler drum (3) is also provided with an exhaust pipe (13), and the superheater (6) is provided on the exhaust pipe (13). The end of the exhaust pipe (13) extends into the flue gas passage (2) and is located on the side of the flue gas passage (2) near the flue gas inlet (4).

2. The flue gas waste heat utilization boiler according to claim 1, characterized in that, The flue gas passage (2) is in the shape of an inverted "U" inside the boiler body (1).

3. A flue gas waste heat utilization boiler according to claim 1, characterized in that, The superheater (6) includes a low-temperature superheater and a high-temperature superheater, wherein the high-temperature superheater is located between the low-temperature superheater and the outlet end of the exhaust pipe (13).

4. A flue gas waste heat utilization boiler according to claim 1, characterized in that, There are multiple economizers (8), and the inlet and outlet of two adjacent economizers (8) are connected by a pipe.

5. A flue gas waste heat utilization boiler according to claim 1, characterized in that, There are multiple convection tube bundles (7), and the liquid inlet end of each convection tube bundle (7) is connected to the liquid outlet pipe (11), and the gas outlet end of each convection tube bundle (7) is connected to the gas inlet pipe (12).

6. A flue gas waste heat utilization boiler according to claim 1, characterized in that, A water-cooled wall (14) is fixed inside the flue gas passage (2).

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