Low-calorific-value gas waste heat utilization system

Abstract

The utility model discloses a low heat value coal gas waste heat utilization system belongs to lead and zinc fire metallurgy technical field. Including low heat value coal gas delivery main pipe, be connected with the discharge branch pipe on low heat value coal gas delivery main pipe, and the export end of low heat value coal gas delivery main pipe inserts into the waste heat boiler, and the output end pipe section of discharge branch pipe is equipped with the blanking blind plate, and the water seal and bypass of parallel installation are additionally installed on the side of blanking blind plate of discharge branch pipe, electric regulating valve is installed on bypass. The utility model satisfies the low heat value coal gas flow required when waste heat boiler normal load works, and guarantees that the CO partial pressure of closed blast furnace hearth satisfies the reduction condition required when smelting.

Description

Technical Field

[0001] This utility model relates to the field of lead-zinc pyrometallurgical technology, specifically to a low-calorific-value coal gas waste heat utilization system. Background Technology

[0002] In the reduction smelting process of the ISP process in a closed blast furnace, coke added to the furnace reacts with oxygen at a high temperature of approximately 1000℃ to generate carbon monoxide, which reduces the sintered agglomerates (mainly composed of PbO and ZnO) to produce liquid lead and zinc vapors. During the reduction process, coke needs to be continuously replenished and low-concentration CO gas discharged from the furnace needs to be controlled to maintain a good reducing atmosphere inside the furnace. The low-concentration CO produced during the reduction process in the closed blast furnace has a concentration of 24% and a calorific value of 1000 KJ / Nm³. 3 The low-calorific-value gas has good reuse value, and a factory plans to build a waste heat boiler to reuse it. The flow rate of low-calorific-value gas generated by the closed blast furnace is greater than that required for the normal operation of the waste heat boiler. When designing the low-calorific-value gas transmission pipeline, it is necessary to take into account both the operating load of the waste heat boiler and the furnace pressure of the closed blast furnace. Part of the low-calorific-value gas is sent to the boiler for waste heat utilization, and part is sent to subsequent treatment to meet standards before being discharged. It is necessary to avoid "pressure buildup" in the closed blast furnace and to control the flow rate of low-calorific-value gas to meet the normal operating load. Summary of the Invention

[0003] The purpose of this invention is to provide a waste heat utilization system for low-calorific-value coal gas generated by a closed blast furnace in an ISP (Integrated Power System) pyrometallurgical lead-zinc smelting enterprise. This system connects the low-calorific-value coal gas to a waste heat boiler for waste heat utilization, while simultaneously meeting the operating load requirements of the waste heat boiler and the furnace pressure requirements for normal production in the closed blast furnace. This allows for the utilization of this low-concentration CO without affecting the normal production of the closed blast furnace, thereby solving the problems existing in the prior art.

[0004] The technical solution adopted in this utility model is as follows:

[0005] A low-calorific-value coal gas waste heat utilization system includes a low-calorific-value coal gas transmission main pipeline 1, a discharge branch pipe 2 connected to the low-calorific-value coal gas transmission main pipeline 1, a waste heat boiler 3 connected to the outlet end of the low-calorific-value coal gas transmission main pipeline 1, a sealing blind plate 4 provided in the outlet end pipe section of the discharge branch pipe 2, a water seal 5 and a bypass 6 connected in parallel on the side of the sealing blind plate 4 on the discharge branch pipe 2, and an electric regulating valve 7 installed on the bypass 6.

[0006] The waste heat boiler 3 is also connected to a fresh air inlet pipe 8 and a natural gas inlet pipe 9.

[0007] The central axis of the discharge branch pipe 2 forms a 45° angle with the axis of the low-calorific-value gas transmission main pipeline 1.

[0008] Both the main pipeline 1 for transmitting low-calorific-value gas and the branch pipeline 2 for discharging gas are Ф800 Q235 pipes.

[0009] The discharge branch pipe 2 is welded to the low-calorific-value gas transmission main pipeline 1.

[0010] In summary, due to the adoption of the above technical solution, the beneficial effects of this utility model are:

[0011] This utility model connects a discharge branch pipe to the main pipeline for low-calorific-value gas transmission. The central axis of the branch pipe forms a 45° angle with the axis of the main pipeline. This angle is designed according to the flow distribution requirements between the subsequent treatment and discharge process and the waste heat boiler inlet, so as to avoid the occurrence of excessively low-calorific-value gas flow at the waste heat boiler inlet and excessively high pressure in the closed blast furnace.

[0012] This utility model adds a water seal and a bypass to the low-calorific-value gas before it is transported to the subsequent treatment and discharge process in the discharge branch pipe. The original transport pipeline is blocked with a blind flange, and an electric regulating valve is added to the bypass. The flow rate of the low-calorific-value gas transported to the subsequent treatment and discharge process is further adjusted by the valve opening and the water seal level. This achieves the purpose of further adjusting the flow distribution of low-calorific-value gas between the waste heat boiler inlet and the treatment and discharge end. Adjustment is made when the flow rate of low-calorific-value gas generated by the closed blast furnace fluctuates.

[0013] In summary, this utility model not only meets the low calorific value gas flow required for normal load operation of the waste heat boiler, but also ensures that the CO partial pressure in the closed blast furnace meets the reduction conditions required during smelting. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the overall structure of this utility model;

[0015] Figure 2 for Figure 1 A schematic diagram of the local structure at point A;

[0016] In the diagram: 1. Low-calorific-value gas transmission main pipeline; 2. Discharge branch pipe; 3. Waste heat boiler; 4. Sealing blind flange; 5. Water seal; 6. Bypass; 7. Electric regulating valve; 8. Fresh air inlet pipeline; 9. Gas inlet pipeline; 10. Boiler drum; 11. Smoke exhaust chimney; 12. Smoke exhaust fan; 13. Blower. Detailed Implementation

[0017] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments. The components of the embodiments of this utility model described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0018] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0019] In the description of this utility model, it should be understood that the terms "upper", "lower", "front", "rear", "left", "right", "top", "bottom", "inner", and "outer" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model. Example

[0020] like Figure 1-2 This embodiment provides a low-calorific-value coal gas waste heat utilization system, including a Ф800 low-calorific-value coal gas transmission main pipeline 1. A Ф800 Q235 material discharge branch pipe 2 is connected to the low-calorific-value coal gas transmission main pipeline 1, and the discharge branch pipe 2 is welded to the low-calorific-value coal gas transmission main pipeline 1. The central axis of the discharge branch pipe 2 forms a 45° angle with the axis of the low-calorific-value coal gas transmission main pipeline 1. This 45° angle is designed according to the flow distribution requirements between the subsequent treatment and discharge process and the waste heat boiler inlet, to avoid the low-calorific-value coal gas flow rate at the waste heat boiler inlet and the furnace pressure of the closed blast furnace being too high. The outlet end of the low-calorific-value coal gas transmission main pipeline 1 is connected to the waste heat boiler 3. A blind flange 4 is provided in the outlet section of the discharge branch pipe 2. A water seal 5 and a bypass 6 are installed in parallel on the side of the blind flange 4 on the discharge branch pipe 2. An electric regulating valve 7 is installed on the bypass 6. The flow rate of low-calorific-value gas delivered to the subsequent treatment and discharge process is further adjusted by the opening degree of the electric regulating valve 7 and the water level of the water seal 5. This achieves the purpose of further adjusting the flow distribution of low-calorific-value gas between the waste heat boiler inlet and the treatment and discharge outlet. Adjustment is made when the flow rate of low-calorific-value gas generated by the closed blast furnace fluctuates.

[0021] The waste heat boiler 3 is also connected to a fresh air inlet pipe 8 and a natural gas inlet pipe 9.

[0022] This invention connects the low-calorific-value gas generated by the closed blast furnace in the ISP pyrometallurgical lead-zinc smelting enterprise to the waste heat boiler for waste heat utilization. This not only meets the low-calorific-value gas flow required for the normal load operation of the waste heat boiler, but also ensures that the CO partial pressure in the closed blast furnace meets the reduction conditions required during smelting.

Claims

1. A low-calorific-value coal gas waste heat utilization system, comprising a main pipeline for transmitting low-calorific-value coal gas (1), characterized in that, The low-calorific-value gas transmission main pipeline (1) is connected to a discharge branch pipe (2). The outlet end of the low-calorific-value gas transmission main pipeline (1) is connected to a waste heat boiler (3). A blind flange (4) is provided in the outlet section of the discharge branch pipe (2). A water seal (5) and a bypass (6) are installed in parallel on the side of the blind flange (4) on the discharge branch pipe (2). An electric regulating valve (7) is installed on the bypass (6).

2. The low-calorific-value coal gas waste heat utilization system according to claim 1, characterized in that: The waste heat boiler (3) is also connected to a fresh air inlet pipe (8) and a natural gas inlet pipe (9).

3. The low-calorific-value coal gas waste heat utilization system according to claim 1, characterized in that: The central axis of the discharge branch pipe (2) forms a 45° angle with the axis of the low-calorific-value gas transmission main pipeline (1).

4. A low-calorific-value coal gas waste heat utilization system according to claim 1, characterized in that: The main pipeline (1) for transmitting low-calorific-value coal gas and the branch pipeline (2) for discharging it are both Q235 pipelines with a diameter of Ф800.

5. A low-calorific-value coal gas waste heat utilization system according to claim 1, characterized in that: The discharge branch pipe (2) is welded to the low-calorific-value gas transmission main pipeline (1).

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