A device for recovering waste heat from raw coal gas and a method for preventing black smoke

Abstract

The application discloses a raw coal gas waste heat recovery device and a method for preventing black smoke generation, wherein the raw coal gas waste heat recovery device comprises an ascending pipe body; the ascending pipe body comprises an inner pipe and an outer pipe coaxially arranged outside the inner pipe, and a jacket is formed between the inner pipe and the outer pipe; and a heat exchange pipe is spirally wound on the inner pipe. The jacket is formed between the inner pipe and the outer pipe, and an upper connecting port and a lower connecting port are arranged on the jacket respectively, heat is taken away by the jacket and the heat exchange pipe, the heat of raw coal gas is absorbed to generate water vapor mixture, saturated water vapor or to produce superheated steam, the heat exchange effect is good, meanwhile, the upper connecting port and the lower connecting port can inject steam into the jacket when black smoke appears, so that the heat exchange effect is reduced, the generation of black smoke is avoided, the operation is simple, the effect is obvious, the generation of black smoke is avoided as much as possible without affecting the production, the production benefit is ensured, and environmental pollution is avoided.

Description

Technical Field

[0001] This invention relates to the field of waste gas heat recovery technology, and in particular to a waste gas waste heat recovery device and a method for preventing the generation of black smoke. Background Technology

[0002] The most important equipment for waste heat recovery from raw coal gas is the riser pipe waste heat recovery device. Coil-type riser pipe waste heat recovery devices are widely used due to their simple structure, ease of manufacture, and high heat exchange efficiency. However, after the raw coal gas undergoes vaporization and cooling, tar condenses at the dew point, releasing large amounts of black smoke and polluting the environment. To address this, the usual approach is to reduce the circulating water volume to decrease the heat absorption of the riser pipe waste heat recovery device. However, this method is relatively simplistic, and a typical coke oven has over a hundred riser pipes. Relying on the adjustment of a single water pump in conjunction with a throttling orifice plate to control the heat absorption of the heat exchange device results in a huge workload and makes dynamic balancing difficult. Summary of the Invention

[0003] The purpose of this invention is to address the problem that existing riser pipe waste heat recovery devices require a huge amount of work to eliminate black smoke and are difficult to dynamically balance, and to propose a waste gas waste heat recovery device and a method to prevent black smoke generation.

[0004] The technical solution to achieve the purpose of this invention is: a waste heat recovery device for raw coal gas, comprising a riser body: the riser body includes an inner tube and an outer tube coaxially disposed outside the inner tube, and a jacket is formed between the inner tube and the outer tube; a heat exchange tube is spirally wound on the inner tube; a water inlet and a steam outlet communicating with the inlet and outlet of the heat exchange tube are respectively provided on the outer tube; an upper connection port and a lower connection port communicating with the jacket are respectively provided at both ends of the outer tube.

[0005] Both ends of the riser pipe body are equipped with connecting flanges.

[0006] The heat exchange tube has a D-shaped cross-section that fits against the inner tube wall.

[0007] The heat exchange tube is spiraled upwards from the bottom of the inner tube, and the overall height of the heat exchange tube is 2 / 3 of the length of the inner tube.

[0008] The outer wall of the heat exchange tube is coated with a waterproof layer.

[0009] A method for preventing black smoke from the aforementioned waste heat recovery device for raw coal gas includes the following steps:

[0010] S1: Keep the water inlet in the heat exchange tube and the jacket constant, and slowly inject a small amount of steam into the jacket in a counter-current manner. If the black smoke is not eliminated, then use S2.

[0011] S2: Keep the water inlet in the heat exchange tube and the jacket constant, and inject a large amount of steam into the jacket in a co-current manner. If the black smoke is not eliminated, then use S3.

[0012] S3: Reduce the water flow rate into the heat exchange tubes and jacket, and inject high-temperature steam into the jacket again in a co-current manner. If the black smoke is still not eliminated, then use S4.

[0013] S4: Close the water inlet to the heat exchange tubes and jacket, and then inject a large amount of high-temperature steam in a co-current manner until the black smoke disappears.

[0014] The present invention has the following beneficial effects by adopting the above technical solution: (1) A jacket is formed between the inner tube and the outer tube of the present invention, and an upper connection port and a lower connection port are respectively provided on the jacket. Heat is extracted in stages by the jacket and the heat exchange tube. The heat of the raw coal gas is absorbed to produce water vapor mixture, saturated steam or superheated steam, and the heat exchange effect is better. At the same time, when black smoke appears, steam can be injected into the jacket through the upper connection port and the lower connection port to reduce the heat exchange effect and thus avoid the generation of black smoke. The operation is simple and the effect is obvious. Black smoke is avoided as much as possible without affecting production, ensuring production efficiency while avoiding environmental pollution.

[0015] (2) The present invention is provided with a flange to facilitate the overall installation of the device.

[0016] (3) The heat exchange tube of the present invention has a D-shaped cross section that fits the inner tube wall, which increases the contact area between the heat exchange tube and the inner tube wall and improves the heat exchange effect.

[0017] (4) The overall height of the heat exchange tube of the present invention is 2 / 3 of the length of the inner tube, which avoids excessive heat exchange efficiency and causes black smoke to be released from the top of the inner tube, thus reducing the risk of black smoke emission.

[0018] (5) The waterproof layer sprayed on the outer wall of the heat exchange tube in this invention provides good protection for the heat exchange tube and prevents the high-temperature water in the jacket from damaging the heat exchange tube.

[0019] (6) The present invention provides a method for preventing the generation of black smoke by heating the heat exchange medium in the jacket, thereby reducing the overall heat exchange effect of the device and thus avoiding the generation of black smoke. Attached Figure Description

[0020] To make the content of this invention easier to understand, the invention will be further described in detail below with reference to specific embodiments and accompanying drawings, wherein...

[0021] Figure 1 This is a schematic diagram of the structure of the present invention.

[0022] The labels in the attached diagram are:

[0023] Ascension pipe body 1, inner pipe 1-1, outer pipe 1-2, jacket 2, upper connection port 2-1, lower connection port 2-2, heat exchange pipe 3, water inlet 3-1, steam outlet 3-2. Detailed Implementation

[0024] (Example 1)

[0025] See Figure 1 This embodiment of a waste heat recovery device for raw coal gas includes a riser body 1: the riser body 1 includes an inner tube 1-1 and an outer tube 1-2 coaxially disposed outside the inner tube 1-1, and a jacket 2 is formed between the inner tube 1-1 and the outer tube 1-2; a heat exchange tube 3 is spirally wound on the inner tube 1-1; the outer tube 1-2 is respectively provided with a water inlet 3-1 and a steam outlet 3-2 communicating with the inlet and outlet of the heat exchange tube 3; the two ends of the outer tube 1-2 are respectively provided with an upper connection port 2-1 and a lower connection port 2-2 communicating with the jacket 2.

[0026] Furthermore, to facilitate the overall installation of the device, both ends of the riser body 1 are provided with connecting flanges.

[0027] Furthermore, the heat exchange tube 3 has a D-shaped cross-section that fits against the wall of the inner tube 1-1, which can effectively increase the contact area between the heat exchange tube 3 and the wall of the inner tube 1-1, thereby improving the heat exchange effect.

[0028] Furthermore, the heat exchange tube 3 is spiraled upwards from the bottom of the inner tube 1-1, and the overall height of the heat exchange tube 3 is 2 / 3 of the length of the inner tube 1-1. This avoids excessive heat exchange efficiency, which could cause black smoke to be released from the top of the inner tube 1-1, thus reducing the risk of black smoke emission.

[0029] Furthermore, the outer wall of the heat exchange tube 3 is coated with a waterproof layer, which can provide good protection for the heat exchange tube 3 and prevent the high-temperature water in the jacket 2 from damaging the heat exchange tube 3.

[0030] A method for preventing black smoke from the aforementioned waste heat recovery device for raw coal gas includes the following steps:

[0031] S1: Keep the water inlet in heat exchange tube 3 and jacket 2 unchanged, and slowly inject a small amount of steam into jacket 2 in a counter-current manner. If the black smoke is not eliminated, then use S2.

[0032] S2: Keep the water inlet in heat exchange tube 3 and jacket 2 unchanged, and inject a large amount of steam into jacket 2 in a co-current manner. If the black smoke is not eliminated, then use S3.

[0033] S3: Reduce the water flow rate in heat exchange tube 3 and jacket 2, and inject high-temperature steam into jacket 2 again in a co-current manner. If the black smoke is still not eliminated, then use S4.

[0034] S4: Close the water inlet of heat exchange tube 3 and jacket 2, and then inject a large amount of high-temperature steam in a co-current manner until the black smoke disappears.

[0035] The waste heat recovery device for raw coal gas in this embodiment is not only simple in structure, but also only requires connecting the upper connection port 2-1 and the lower connection port 2-2 of the jacket 2 to the corresponding water / steam interfaces, and switching between co-current and counter-current flow by valves, thereby heating the medium inside the jacket 2, thereby heating the wall of the inner tube 1-1, reducing heat exchange efficiency, and thus avoiding the generation of black smoke. It can prevent the generation of black smoke as much as possible without affecting production, achieving both production efficiency and environmental protection.

[0036] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preventing black smoke from a waste heat recovery device for slag gas, characterized in that: The waste heat recovery device for raw coal gas includes a riser body (1), which includes an inner tube (1-1) and an outer tube (1-2) coaxially disposed outside the inner tube (1-1), and a jacket (2) is formed between the inner tube (1-1) and the outer tube (1-2); a heat exchange tube (3) is spirally wound on the inner tube (1-1); and the outer tube (1-2) is provided with a water inlet (3-1) and a steam outlet respectively connected to the inlet and outlet of the heat exchange tube (3). Outlet (3-2); the two ends of the outer tube (1-2) are respectively provided with an upper connection port (2-1) and a lower connection port (2-2) communicating with the jacket (2); both ends of the riser body (1) are provided with connecting flanges; the cross section of the heat exchange tube (3) is D-shaped and fits against the wall of the inner tube (1-1); the heat exchange tube (3) is spiraled upward from the bottom of the inner tube (1-1), and the overall height of the heat exchange tube (3) is 2 / 3 of the length of the inner tube (1-1); The method for preventing black smoke from the waste heat recovery device for raw coal gas includes the following steps: S1: Keep the water inlet in the heat exchange tube (3) and the jacket (2) unchanged, and slowly inject a small amount of steam into the jacket (2) in a countercurrent manner. If the black smoke is not eliminated, then use S2. S2: Keep the water inlet in the heat exchange tube (3) and the jacket (2) unchanged, and inject a large amount of steam into the jacket (2) in a co-current manner. If the black smoke is not eliminated, then use S3. S3: Reduce the amount of water entering the heat exchange tube (3) and the jacket (2), and inject high-temperature steam into the jacket (2) again in a co-current manner. If the black smoke is still not eliminated, then use S4. S4: Close the water inlet of the heat exchange tube (3) and the jacket (2), and then inject a large amount of high-temperature steam in a co-current manner until the black smoke disappears.

2. The method for preventing black smoke from the waste heat recovery device of raw coal gas according to claim 1, characterized in that: The outer wall of the heat exchange tube (3) is coated with a waterproof layer.

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