Air separation unit capable of keeping oxygen extraction rate under liquid nitrogen extraction

Abstract

The utility model belongs to the technical field of air separation unit equipment, and relates to an air separation unit capable of keeping oxygen extraction rate under liquid nitrogen extraction, which comprises a fractionating tower, an oxygen taking pipe arranged on one side of the middle of the fractionating tower, an oxygen valve arranged on the oxygen taking pipe, a waste nitrogen taking pipe arranged on one side of the top of the fractionating tower, a waste nitrogen valve arranged on the waste nitrogen taking pipe and a detector. A liquid nitrogen taking pipe is arranged on one side of the top of the fractionating tower and connected to a liquid nitrogen storage tank, and a liquid nitrogen valve is arranged on the front side of the liquid nitrogen storage tank. According to the utility model, through the interlocking control of valves and test analysis data, reasonable extraction of liquid nitrogen products is realized, and the operation economy of an air separation unit is improved.

Description

Technical Field

[0001] The utility model belongs to the technical field of air separation unit equipment, and in particular relates to an air separation unit capable of maintaining an oxygen extraction rate under liquid nitrogen extraction. Background Art

[0002] In the air separation unit distillation tower, the components in the raw air are separated according to their different boiling points. In the extraction of liquid nitrogen products, the reflux ratio of the distillation section of the upper tower of the distillation tower will be changed, causing the oxygen component content in the contaminated nitrogen product to increase, thereby reducing the oxygen extraction rate.

[0003] The existing air separation unit liquid nitrogen extraction valve is manually controlled, and the operation of the liquid nitrogen extraction valve depends on the operator's experience level, and cannot track the test analysis data of the dirty nitrogen product in time, which easily causes the oxygen content in the dirty nitrogen gas to rise, affecting the extraction and utilization of oxygen products. Therefore, an air separation unit that maintains the oxygen extraction rate under liquid nitrogen extraction is proposed. Utility Model Content

[0004] The utility model aims to provide an air separation unit capable of maintaining oxygen extraction rate under liquid nitrogen extraction, which has the function of maintaining oxygen extraction rate under liquid nitrogen extraction, solves the problem that the prior art is manually controlled, and the operation of the liquid nitrogen extraction valve depends on the experience level of the operator, and the test analysis data of the dirty nitrogen product cannot be tracked in time, which easily causes the oxygen content in the dirty nitrogen gas to rise, so that the extraction and utilization of the oxygen product are affected.

[0005] In order to achieve the above-mentioned purpose, the technical solution adopted by the utility model is as follows: the utility model provides an air separation unit for maintaining oxygen extraction rate under liquid nitrogen extraction, comprising a distillation tower, an oxygen extraction pipe is arranged on one side of the middle part of the distillation tower, an oxygen valve is arranged on the oxygen extraction pipe, a dirty nitrogen extraction pipe is arranged on one side of the top of the distillation tower, a dirty nitrogen valve and a detector are arranged on the dirty nitrogen extraction pipe, a liquid nitrogen extraction pipe is arranged on one side of the top of the distillation tower, the liquid nitrogen extraction pipe is connected to a liquid nitrogen storage tank, and a liquid nitrogen valve is arranged on the front side of the liquid nitrogen storage tank.

[0006] Preferably, the interior of the distillation tower is divided into two layers, and a condenser evaporator is arranged at the center of the distillation tower.

[0007] Preferably, an air inlet pipe is provided at the bottom of the distillation tower, and an air inlet valve is provided on the air inlet pipe.

[0008] Preferably, the detector is electrically connected to the liquid nitrogen valve.

[0009] Preferably, a nitrogen intake pipe is provided at the top of the fractionation tower, and a nitrogen valve is provided on the nitrogen intake pipe.

[0010] Preferably, a throttle valve is provided at the front end of the liquid nitrogen extraction tube.

[0011] Compared with the prior art, the advantages and positive effects of the utility model are:

[0012] 1. The utility model realizes the reasonable extraction of liquid nitrogen products and improves the operating economy of the air separation unit by designing the interlocking control of the valve and the test analysis data;

[0013] 2. The utility model has the function of maintaining the oxygen extraction rate under liquid nitrogen extraction, which solves the problem that the operation of the liquid nitrogen extraction valve in the prior art depends on the experience level of the operator and cannot track the test and analysis data of the contaminated nitrogen product in time, which easily causes the oxygen content in the contaminated nitrogen gas to increase, thereby affecting the extraction and utilization of the oxygen product. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] In order to more clearly illustrate the technical solutions of the embodiments of the utility model, the following is a brief introduction to the drawings required for use in the description of the embodiments. Obviously, the drawings described below are some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative labor.

[0015] Figure 1 It is a structural schematic diagram of an air separation unit that maintains oxygen extraction rate under liquid nitrogen extraction;

[0016] In the above figure, 1. distillation tower, 2. air inlet pipe, 3. air inlet valve, 4. oxygen extraction pipe, 5. oxygen valve, 6. dirty nitrogen extraction pipe, 7. dirty nitrogen valve, 8. detector, 9. nitrogen extraction pipe, 10. nitrogen valve, 11. liquid nitrogen extraction pipe, 12. liquid nitrogen storage tank, 13. throttle valve, 14. liquid nitrogen valve. DETAILED DESCRIPTION

[0017] In order to more clearly understand the above-mentioned purpose, features and advantages of the utility model, the utility model is further described below in conjunction with the accompanying drawings and embodiments. It should be noted that the embodiments of the present application and the features in the embodiments can be combined with each other without conflict.

[0018] In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention may also be implemented in other ways than those described herein. Therefore, the present invention is not limited to the specific embodiments of the following disclosure.

[0019] Embodiment 1, as Figure 1As shown, an air separation unit for maintaining oxygen extraction rate under liquid nitrogen extraction includes a fractionation tower 1, which plays the role of fractionating various components in the air, and realizes the extraction of different components by separating gases with different boiling points in the tower. An oxygen extraction pipe 4 is arranged on one side of the middle part of the fractionation tower 1, and the oxygen extraction pipe 4 is used to extract the oxygen gas fractionated in the fractionation tower 1, and further extract oxygen products. An oxygen valve 5 is arranged on the oxygen extraction pipe 4, and the oxygen valve 5 controls the flow of oxygen in the oxygen extraction pipe 4 to realize the extraction control of oxygen.

[0020] A dirty nitrogen extraction pipe 6 is provided on one side of the top of the fractionation tower 1. The dirty nitrogen extraction pipe 6 is used to extract the dirty nitrogen fractionated in the fractionation tower 1. A dirty nitrogen valve 7 and a detector 8 are provided on the dirty nitrogen extraction pipe 6. The dirty nitrogen valve 7 controls the opening and closing of the dirty nitrogen extraction pipe 6. The detector 8 can collect and detect the composition data of the dirty nitrogen, which is used to monitor the content of each component in the dirty nitrogen product and timely feedback to the system. A liquid nitrogen extraction pipe 11 is provided on one side of the top of the fractionation tower 1. The liquid nitrogen extraction pipe 11 is connected to a liquid nitrogen storage tank 12. The liquid nitrogen storage tank 12 is used to store liquid nitrogen products. The liquid nitrogen extraction pipe 11 transports the extracted liquid nitrogen to the liquid nitrogen storage tank 12. A liquid nitrogen valve 14 is provided on the front side of the liquid nitrogen storage tank 12. The liquid nitrogen valve 14 controls the flow of the liquid nitrogen product in the liquid nitrogen storage tank 12, thereby realizing the control of the extraction and storage of the liquid nitrogen product.

[0021] The following is a detailed description of the design of the above key components:

[0022] The interior of the distillation tower 1 is divided into two layers, which can improve the distillation efficiency of the distillation tower 1 and make it easier to separate different components. A condenser evaporator is arranged in the center of the distillation tower 1. The condenser evaporator is also called the main cooler, which helps to cool and condense the gas and facilitates liquefaction and evaporation during the separation process.

[0023] The bottom of the fractionation tower 1 is provided with an air inlet pipe 2, and an air inlet valve 3 is provided on the air inlet pipe 2. The design of the air inlet pipe 2 allows air to smoothly enter the fractionation tower 1 to ensure sufficient supply of raw gas, and the air inlet valve 3 can accurately control the flow rate of the intake air to ensure the stability of the fractionation process.

[0024] The detector 8 is electrically connected to the liquid nitrogen valve 14 to achieve real-time monitoring and control of the extraction of the liquid nitrogen product. Through the transmission of electronic signals, the opening and closing state of the liquid nitrogen valve 14 can be adjusted according to the data of the detector 8, making the extraction of the liquid nitrogen product more accurate and efficient.

[0025] A nitrogen extraction pipe 9 is provided at the top of the fractionation tower 1, and a nitrogen valve 10 is provided on the nitrogen extraction pipe 9. The nitrogen extraction pipe 9 can facilitate the extraction of nitrogen products in the fractionation tower 1, and the setting of the nitrogen valve 10 can control the extraction speed and amount of nitrogen, ensuring that the extraction of nitrogen products meets the extraction requirements.

[0026] The front end of the liquid nitrogen extraction pipe 11 is provided with a throttle valve 13. The throttle valve 13 can limit the size of the liquid nitrogen flow rate, realize accurate and effective extraction of the liquid nitrogen product, and adjust the opening of the throttle valve 13 to limit the flow rate of the liquid nitrogen.

[0027] Example 2, an air separation unit for maintaining oxygen extraction rate under liquid nitrogen extraction as shown in Example 1, working description:

[0028] The raw air is controlled by the air inlet valve 3 and enters the lower tower of the fractionation tower 1 for preliminary distillation and separation. Under the control of the throttle valve 13, it enters the upper tower of the fractionation tower 1 for further distillation and separation. The nitrogen product is obtained at the top of the fractionation tower 1, the liquid oxygen product is accumulated at the condenser evaporator of the fractionation tower 1, and the oxygen product is taken out from one side of the fractionation tower 1. In addition, in order to maintain the purity of the oxygen and nitrogen products, the intermediate product dirty nitrogen is drawn out from the dirty nitrogen extraction pipe 6 through the control of the dirty nitrogen valve 7.

[0029] The production of liquid nitrogen is mainly controlled by the liquid nitrogen valve 14, which draws out the liquid nitrogen into the liquid nitrogen storage tank 12 for storage and utilization. Among them, the oxygen content in the contaminated nitrogen gas is controlled below 2% under normal working conditions. As an intermediate product of distillation separation, the contaminated nitrogen gas is critical for the production of high-purity oxygen and nitrogen after proper extraction. At the same time, controlling the oxygen content in the contaminated nitrogen gas within a reasonable range is also a key measure to ensure the oxygen extraction rate.

[0030] The liquid nitrogen valve 14 is designed to be interlocked with the detector 8 to convert manual control into automatic interlock tracking. The liquid nitrogen valve 14 is adjusted to control the content of the polluted nitrogen component and the upper limit opening is designed.

[0031] Liquid nitrogen is extracted based on the purity of dirty nitrogen. The measurement value of the liquid nitrogen valve 14 is set to 1.5%, which is less than the analysis control index of daily dirty nitrogen gas. The PID control strategy of the liquid nitrogen valve 14 automatically extracts liquid nitrogen products according to the purity of dirty nitrogen gas. It avoids the instability of working conditions caused by delayed and improper human operation. According to daily experience data, the upper limit of the opening of the liquid nitrogen valve 14 is designed to make the liquid nitrogen valve 14 automatically adjust.

[0032] The standard parts used in the utility model can all be purchased from the market, special-shaped parts can be customized according to the description in the specification and the drawings, the specific connection methods of each part adopt the conventional means such as mature bolts, rivets, welding, etc. in the prior art, the machinery, parts and equipment all adopt the conventional models in the prior art, and the circuit connection adopts the conventional connection method in the prior art, which will not be described in detail here. The content not described in detail in this specification belongs to the prior art known to professional and technical personnel in this field.

[0033] The above description is only a preferred embodiment of the present invention and does not limit the present invention in other forms. Any technician familiar with the profession may use the technical content disclosed above to change or modify it into an equivalent embodiment with equivalent changes and apply it to other fields. However, any simple modification, equivalent change and modification made to the above embodiment based on the technical essence of the present invention without departing from the content of the technical solution of the present invention still falls within the protection scope of the technical solution of the present invention.

Claims

1. An air separation unit for maintaining oxygen extraction rate under liquid nitrogen extraction, characterized in that: The invention comprises a fractionating tower, wherein an oxygen taking pipe is arranged on one side of the middle of the fractionating tower, an oxygen valve is arranged on the oxygen taking pipe, a waste nitrogen taking pipe is arranged on one side of the top of the fractionating tower, a waste nitrogen valve and a detector are arranged on the waste nitrogen taking pipe, a liquid nitrogen taking pipe is arranged on one side of the top of the fractionating tower, the liquid nitrogen taking pipe is connected to a liquid nitrogen storage tank, and a liquid nitrogen valve is arranged on the front side of the liquid nitrogen storage tank.

2. An air separation unit for maintaining oxygen extraction rate under liquid nitrogen extraction according to claim 1, characterized in that: The interior of the distillation tower is divided into two layers, and a condenser evaporator is arranged at the center of the distillation tower.

3. The air separation unit for maintaining oxygen extraction rate under liquid nitrogen extraction according to claim 1, characterized in that: An air inlet pipe is arranged at the bottom of the fractionation tower, and an air inlet valve is arranged on the air inlet pipe.

4. The air separation unit for maintaining oxygen extraction rate under liquid nitrogen extraction according to claim 1, characterized in that: The detector is electrically connected to the liquid nitrogen valve.

5. The air separation unit for maintaining oxygen extraction rate under liquid nitrogen extraction according to claim 1, characterized in that: A nitrogen extraction pipe is arranged on the top of the fractionation tower, and a nitrogen valve is arranged on the nitrogen extraction pipe.

6. The air separation unit for maintaining oxygen extraction rate under liquid nitrogen extraction according to claim 1, characterized in that: A throttle valve is arranged at the front end of the liquid nitrogen taking pipe.

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