Double-valve interlocking type nitrogen production and supply system

Abstract

The utility model belongs to the technical field of nitrogen production and supply systems, and particularly relates to a double-valve interlocking type nitrogen production and supply system. Comprising a first air supply system and a second air supply system, the first air supply system and the second air supply system each comprise an air separation machine, the output ends of the two air separation machines are sequentially connected with a grid connection valve and a flow meter through an air supply pipeline, an emptying valve is connected to the air supply pipeline in parallel, the air supply pipeline is connected with a water cooling tower through a heat exchange pipeline, and a heat exchange valve is installed on the heat exchange pipeline. The two flow meters are connected through a nitrogen pipe network, and the nitrogen pipe network is connected with a medium-pressure nitrogen compressor, a low-pressure nitrogen compressor, a flow meter, a heat exchange valve and a blowoff valve electrical interlock in the 1 # gas supply system and a flow meter, a heat exchange valve and a blowoff valve electrical interlock in the 2 # gas supply system in parallel. By automatically controlling the nitrogen production and supply process of the air separation machine, manpower is reduced, and various problems caused by untimely manual operation are prevented.

Description

Technical Field

[0001] The utility model belongs to the technical field of nitrogen production and supply systems, and particularly relates to a double-valve interlocking nitrogen production and supply system. Background Technique

[0002] The air separation unit supporting the steel mill uses the deep refrigeration method to separate air and produce high-purity oxygen and nitrogen for metal smelting production. With the continuous expansion of the design scale of the steel mill, the number and output of the supporting air separation units also increase. Among them, there is a problem of product aggregation and supply for nitrogen production and supply. The nitrogen products produced by two air separation units are aggregated into one pipeline, and then boosted by nitrogen compressors with different pressure grades for nitrogen supply to the steel mill. The control of the nitrogen valves of the two air separation units is manually operated. If abnormal situations such as a single air separation unit tripping occur, the operator manually opens the nitrogen product extraction valve of the operating unit and manually closes the nitrogen product extraction valve of the shutdown unit. Thus, sufficient suction volume of the nitrogen compressor in the operating state and the safety of the shutdown unit are ensured. This method has the following deficiencies:

[0003] 1. Manual operation requires a lot of energy. In daily production, the main operator of the air separation unit needs to specifically pay attention to the production conditions of different units. For emergency adjustment to ensure the external supply of nitrogen.

[0004] 2. Manual operation is not timely, which easily causes a decline in product quality and even pressure loss of the unit. After the unit shuts down, production is interrupted, and unqualified nitrogen enters the external supply pipeline network, affecting the use of the steel mill. Secondly, after the unit shuts down and then extracts products, it is easy to cause the pressure of the device to drop excessively, which is easy to damage the equipment. Summary of the Invention

[0005] The purpose of the utility model is to provide a double-valve interlocking nitrogen production and supply system to solve the problems existing in the prior art.

[0006] The technical solution adopted by the utility model to solve its technical problems is:

[0007] A double-valve interlocking nitrogen production and supply system includes a No. 1 gas supply system and a No. 2 gas supply system. Both the No. 1 gas supply system and the No. 2 gas supply system include air separation machines. The output ends of the two air separation machines are sequentially connected with grid connection valves and flow meters through gas supply pipelines. A vent valve is connected in parallel on the gas supply pipeline. The gas supply pipeline is connected with a water cooling tower through a heat exchange pipeline. A heat exchange valve is installed on the heat exchange pipeline. The two flow meters are connected through a nitrogen pipeline network. A medium-pressure nitrogen compressor and a low-pressure nitrogen compressor are connected in parallel on the nitrogen pipeline network. The flow meter, heat exchange valve, and vent valve in the No. 1 gas supply system are electrically interlocked. The flow meter, heat exchange valve, and vent valve in the No. 2 gas supply system are electrically interlocked. The grid connection valve in the No. 1 gas supply system and the grid connection valve in the No. 2 gas supply system are electrically interlocked.

[0008] Further, the vent valve and the heat exchange pipeline are located on the gas supply pipeline between the output end of the air separation machine and the grid connection valve.

[0009] The utility model has the following beneficial effects:

[0010] 1. By automatically controlling the nitrogen production and supply process of the air separation machine, the labor is reduced, and various problems caused by untimely manual operation are prevented.

[0011] 2. The surplus nitrogen is used for heat exchange through the heat exchange pipeline, so that the surplus nitrogen is recycled, and the power of the air separation machine does not need to be frequently adjusted, enabling the nitrogen production to operate smoothly.

[0012] 3. Through the electrical interlock of the flow meter, the heat exchange valve, and the vent valve, the automatic distribution of nitrogen is realized, and while meeting the nitrogen supply of the steel mill, the automatic adjustment within each gas supply system is achieved.

[0013] 4. Through the interlock of the two grid connection valves, when a problem occurs in one air separation machine, the nitrogen supply can still be ensured in terms of quality and quantity. Description of the Drawings

[0014] Figure 1 It is a schematic structural diagram of the utility model.

[0015] Wherein: 1. 1# gas supply system; 2. 2# gas supply system; 3. air separation machine; 4. gas supply pipeline; 5. grid connection valve; 6. flow meter; 7. vent valve; 8. heat exchange pipeline; 9. water cooling tower; 10. heat exchange valve; 11. nitrogen gas pipeline network; 12. medium-pressure nitrogen gas compressor; 13. low-pressure nitrogen gas compressor. Detailed Embodiment

[0016] In order to make the purpose, technical solution and advantages of the utility model clearer, the following further describes the utility model in detail with reference to specific embodiments and the accompanying drawings. It should be understood that the specific embodiments described herein are only used to explain the utility model and are not used to limit the utility model.

[0017] Such as Figure 1As shown in the figure, a double-valve interlocked nitrogen production and supply system includes a 1# gas supply system 1 and a 2# gas supply system 2. Both the 1# gas supply system 1 and the 2# gas supply system 2 include an air separation unit 3. The output ends of the two air separation units 3 are sequentially connected with a grid connection valve 5 and a flow meter 6 through a gas supply pipeline 4. A vent valve 7 is connected in parallel on the gas supply pipeline 4. The gas supply pipeline 4 is connected to a water cooling tower 9 through a heat exchange pipeline 8. A heat exchange valve 10 is installed on the heat exchange pipeline 8. The two flow meters 6 are connected through a nitrogen gas pipeline network 11. A medium-pressure nitrogen gas compressor 12 and a low-pressure nitrogen gas compressor 13 are connected in parallel on the nitrogen gas pipeline network 11. The flow meter 6, the heat exchange valve 10, and the vent valve in the 1# gas supply system 1 are electrically interlocked. The flow meter 6, the heat exchange valve 10, and the vent valve in the 2# gas supply system 2 are electrically interlocked. The grid connection valve 5 in the 1# gas supply system 1 and the grid connection valve 5 in the 2# gas supply system 2 are electrically interlocked.

[0018] The vent valve 7 and the heat exchange pipeline 8 are located on the gas supply pipeline 4 between the output end of the air separation unit 3 and the grid connection valve 5.

[0019] The working principle of the present utility model is as follows:

[0020] The nitrogen gas products produced by the air separation unit 3 supporting the steel mill are at normal temperature and the pressure is 10 - 20 kPa. During normal use, the grid connection valves 5 of the 1# gas supply system 1 and the 2# gas supply system 2 are at an opening degree of 50% - 60%, and a small-amplitude adjustment method is adopted to stabilize the intake of the medium-pressure nitrogen gas compressor 12 and the low-pressure nitrogen gas compressor 13. The medium-pressure nitrogen gas compressor 12 boosts the nitrogen gas pressure to 1.6 - 2.1 MPa and then caches it in the nitrogen gas spherical tank for supply to the steel mill. The low-pressure nitrogen gas compressor 13 compresses the product nitrogen gas to 0.6 MPa and then supplies it to the steel mill users as purge gas and protective gas. The surplus nitrogen gas produced by the air separation unit 3 enters the water cooling tower 9 through the control of the heat exchange valve 10 for heat exchange and temperature reduction. The remaining nitrogen gas is discharged into the atmosphere through the vent valve 7. After the heat exchange valve 10 and the flow meter 6 inside the 1# gas supply system 1 and the 2# gas supply system 2 are electrically interlocked through the PID module, the sum of the actual flow values detected by the two flow meters 6 is the detected value. The PID module compares the detected value with the set target value. If the target value < the detected value, that is, the nitrogen gas demand of the steel mill is smaller than the actual flow, it outputs a signal to increase the opening degree, making the heat exchange valve 10 open wider, so that the amount of nitrogen gas supplied to the steel mill decreases. If the target value is still smaller than the detected value after the heat exchange valve 10 is opened wider, it means there is still surplus nitrogen gas, and the vent valve is opened to discharge some nitrogen gas into the atmosphere. On the contrary, if the target value > the detected value, the heat exchange valve 10 is adjusted smaller.

[0021] The electrically controlled valve is usually controlled by a solenoid valve to adjust the opening degree of the valve, and the execution mode can be pneumatic. When the operation signal of the air compressor inside the 1# gas supply system 1 is lost, it indicates that the air compressor has stopped or tripped. The solenoid valve of the grid connection valve 5 inside the 1# gas supply system 1 loses power, causing it to close. At the same time, since the grid connection valve 5 inside the 2# gas supply system 2 is electrically interlocked with it through the PID module, the PID module automatically assigns the opening degree of the grid connection valve 5 inside the 2# gas supply system 2 to 100%, so as to ensure the supply volume of nitrogen in the steel plant. At the same time, the detected value of nitrogen is also the actual flow value of the flowmeter 6 inside the 2# gas supply system 2. The PID module compares the detected value with the set target value, and then automatically adjusts the opening degree of the heat exchange valve 10.

[0022] The embodiments described above are only used to describe the preferred implementation manners of the present invention, and do not limit the concept and scope of the present invention. Without departing from the design concept of the present invention, various modifications and improvements made by those of ordinary skill in the art to the technical solutions of the present invention shall fall within the protection scope of the present invention.

[0023] The technologies, shapes, and structures not described in detail in the present invention are all well-known technologies.

Claims

1. A double valve interlocking nitrogen production and supply system, characterized in that: It comprises a 1# gas supply system and a 2# gas supply system, wherein the 1# gas supply system and the 2# gas supply system both comprise an air separator, the output ends of the two air separators are connected in sequence with a grid-connected valve and a flow meter through a gas supply pipeline, a vent valve is connected in parallel on the gas supply pipeline, the gas supply pipeline is connected with a water cooling tower through a heat exchange pipeline, a heat exchange valve is installed on the heat exchange pipeline, two flow meters are connected through a nitrogen pipeline network, a medium-pressure nitrogen compressor and a low-pressure nitrogen compressor are connected in parallel on the nitrogen pipeline network, the flow meter, the heat exchange valve and the vent valve in the 1# gas supply system are electrically interlocked, the flow meter, the heat exchange valve and the vent valve in the 2# gas supply system are electrically interlocked, and the grid-connected valve in the 1# gas supply system is electrically interlocked with the grid-connected valve in the 2# gas supply system.

2. The double valve interlock nitrogen production and supply system according to claim 1, characterized in that: The vent valve and the heat exchange pipeline are located on the gas supply pipeline between the output end of the air separation unit and the grid-connected valve.

Images