Novel double-tower rectification high-extraction-rate energy-saving nitrogen making device

Abstract

The utility model discloses a novel double-tower rectification high extraction rate energy-saving nitrogen making device which comprises an air compressor, a precooling unit, a molecular sieve purifier and a cold box which are sequentially connected, a main heat exchanger, a high-pressure rectification tower, a low-pressure rectification tower, a main condensation evaporator and an auxiliary condensation evaporator are arranged in the cold box, and the novel double-tower rectification high extraction rate energy-saving nitrogen making device further comprises an expansion machine, the main heat exchanger is connected with the molecular sieve purifier, the high-pressure rectifying tower, the low-pressure rectifying tower, the auxiliary condensation evaporator and the expansion machine; the high-pressure rectifying tower is connected with the main condensing evaporator and the low-pressure rectifying tower; the low-pressure rectifying tower is connected with the main condensation evaporator and the auxiliary condensation evaporator; and the main condensation evaporator is connected with the auxiliary condensation evaporator. The device is high in nitrogen extraction rate, relatively simple in structure, small in occupied area of the fractionating tower cold box and low in operation energy consumption.

Description

TECHNICAL FIELD

[0001] The utility model relates to a novel double-tower rectification high-extraction-rate energy -conserving nitrogen device belongs to nitrogen equipment technical field. BACKGROUND

[0002] The chemical property of nitrogen is not active, has very big inertness under ordinary state, and is not easy to have chemical reaction with other substances. Therefore, nitrogen is widely used to do the protection gas in metallurgy, electronic chemical industry, glass product, metal smelting process. Liquid nitrogen is mainly applied to low temperature physics research, frozen food, refrigerant, preservation living body sample, cryotherapy. Low temperature liquid has superiority in storage and transportation, therefore the demand of low temperature liquid nitrogen is more and more.

[0003] The patent number for CN202121949442.2, the patent name for a novel nitrogen device in the scheme disclosed in, nitrogen product is extracted from the top of a rectifying column in the cold box, and the nitrogen extraction rate is about 70%, the nitrogen extraction rate is relatively low, and the low-pressure liquid nitrogen needs to be pressurized by a liquid nitrogen pump to enter the high-pressure column as a reflux liquid, and the liquid nitrogen pump generally needs to be provided with a separate cold box and pipeline, so that the land area of the entire fractionating column cold box is larger, not only the cost is higher, but also the on-site assembly of the equipment is more complex and cumbersome. UTILITY MODEL CONTENT

[0004] The utility model solves the technical problem to provide a novel double-tower rectification high-extraction-rate energy -conserving nitrogen device, and the nitrogen extraction rate is high, and the structure is relatively simple, the land area of the fractionating column cold box is less, and the operation energy consumption of the device is low.

[0005] In order to solve the above technical problem, the technical scheme adopted by the utility model is:

[0006] A novel double-tower rectification high-extraction-rate energy -conserving nitrogen device, including air compressor precooling unit, molecular sieve purifier and cold box that are connected in sequence, the cold box is provided with main heat exchanger, high-pressure rectifying column, low-pressure rectifying column, main condensation evaporator and auxiliary condensation evaporator, still includes expander, wherein the main heat exchanger is connected with molecular sieve purifier, high-pressure rectifying column, low-pressure rectifying column, auxiliary condensation evaporator and expander;The high-pressure rectifying column is connected with the main condensation evaporator and low-pressure rectifying column;The low-pressure rectifying column is connected with the main condensation evaporator and auxiliary condensation evaporator;The main condensation evaporator is connected with the auxiliary condensation evaporator.

[0007] The foregoing novel double-tower rectification high-extraction-rate energy -conserving nitrogen device, characterized by: the cold box is further provided with supercooler, and the supercooler is connected with the main heat exchanger, high-pressure rectifying column and auxiliary condensation evaporator.

[0008] The aforementioned novel double-tower distillation high-extraction rate energy-saving nitrogen production device is characterized in that the expansion end of the expander is arranged inside the cold box, the boosting end is arranged outside the cold box, and a cooler connected to the boosting end of the expander is also arranged outside the cold box.

[0009] The aforementioned novel double-tower distillation high-extraction-rate energy-saving nitrogen production device is characterized in that the expansion end of the expander is connected to the molecular sieve purifier through a main heat exchanger.

[0010] The aforementioned novel double-tower distillation high-extraction rate energy-saving nitrogen production device is characterized in that a muffler connected to the molecular sieve purifier is further provided outside the molecular sieve purifier, and the muffler is connected to the expansion end of the expander through a main heat exchanger.

[0011] The aforementioned novel double-tower distillation high-extraction rate energy-saving nitrogen production device is characterized in that a residual liquid evaporator is further provided outside the cold box, and the residual liquid evaporator is respectively connected to the high-pressure distillation tower, the low-pressure distillation tower, the main condenser evaporator and the auxiliary condenser evaporator.

[0012] The aforementioned novel double-tower distillation high-extraction-rate energy-saving nitrogen production device is characterized in that an air filter is also connected to the front end of the air compressor.

[0013] The beneficial effects of the utility model are:

[0014] 1. A certain amount of nitrogen is extracted from the top of the high-pressure distillation tower and fed into the low-pressure distillation tower. The nitrogen rectified by the low-pressure distillation tower is heat exchanged and pressurized in the main heat exchanger before being output as product nitrogen. By extracting a portion of nitrogen from the top of each of the two distillation towers, the nitrogen product extraction rate is increased to about 78%;

[0015] 2. After a certain amount of nitrogen extracted from the top of the high-pressure distillation tower is condensed into liquid nitrogen in the main condensation generator, a portion of the liquid nitrogen is returned to the high-pressure distillation tower as reflux liquid. No liquid nitrogen pump is required, making the process more simple and reliable, and also reducing equipment investment costs, operating costs and maintenance costs;

[0016] 3. After the nitrogen leaves the cold box, it is pressurized by the expander and then provided as a product. While meeting the nitrogen product pressure requirements, the exhaust pressure of the air compressor is relatively reduced, thereby reducing power consumption by about 5%. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a structural schematic diagram of a novel double-tower distillation high-extraction rate energy-saving nitrogen production device of the utility model. DETAILED DESCRIPTION

[0018] The present invention will be further described below with reference to the accompanying drawings.

[0019] As Figure 1 shown, a new double-tower rectification high-extraction-rate energy-saving nitrogen production device, comprising air compressor 10, pre-cooling unit 20, molecular sieve purifier 30 and cold box 40 connected in sequence, the cold box 40 is provided with main heat exchanger 41, high-pressure rectification tower 42, low-pressure rectification tower 43, main condensing evaporator 44 and auxiliary condensing evaporator 45, and further comprising expander 60, wherein the main heat exchanger 41 is connected with the molecular sieve purifier 30, high-pressure rectification tower 42, low-pressure rectification tower 43, auxiliary condensing evaporator 45 and expander 60; the high-pressure rectification tower 42 is connected with the main condensing evaporator 44 and low-pressure rectification tower 43; the low-pressure rectification tower 43 is connected with the main condensing evaporator 44 and auxiliary condensing evaporator 45; the main condensing evaporator 44 is connected with the auxiliary condensing evaporator 45. The cold box 40 is further provided with supercooler 46, and the supercooler 46 is connected with the main heat exchanger 41, high-pressure rectification tower 42 and auxiliary condensing evaporator 45.

[0020] In this embodiment, the front end of the air compressor 10 is further connected with an air filter 50, and the raw air enters the air compressor after removing dust through the self-cleaning air filter 50. The air compressed by the air compressor 10 is cooled to about 10℃ by the pre-cooling unit 20, and then enters the molecular sieve purifier 30 to remove residual water, carbon dioxide and hydrocarbons. The dew point of water in the air out of the purifier is less than or equal to -70℃, and the carbon dioxide is less than 1PPm.

[0021] The processed air after purification enters the cold box 40, is cooled to the dew point temperature in the main heat exchanger 41, and then enters the high-pressure rectification tower 42. After rectification of the high-pressure rectification tower 42, the bottom part obtains oxygen-rich liquid air, which is sent to the main condensing evaporator 44 after supercooling by the supercooler 46, and is evaporated. The vapor enters the low-pressure rectification tower 43 for rectification.

[0022] The nitrogen gas at the top of the high-pressure rectification tower 42 is condensed into liquid nitrogen in the main condensing evaporator 44 as the top reflux liquid of the high-pressure rectification tower 42. Another part of the nitrogen gas is sent to the low-pressure rectification tower 43. After rectification of the low-pressure rectification tower 43, part of the nitrogen gas at the top enters the main heat exchanger 41, and is re-heated after cooling the raw air in the main heat exchanger 41, and is discharged from the cold box. After being pressurized by the expander 60, it is used as product nitrogen gas. Another part of the nitrogen gas enters the auxiliary condensing evaporator 45 to be condensed into liquid nitrogen, which is used as the top reflux liquid of the low-pressure rectification tower 43.

[0023] The expansion end of the expander 60 is connected with the molecular sieve purifier 30 through the main heat exchanger 41, low-pressure rectification tower 43 bottom liquid air throttle enters the auxiliary condensation evaporator 45 to evaporate, the oxygen-enriched air is cooled through the supercooler 46, reheated in the main heat exchanger 41 and then enters the expansion end of the expander 60, the expanded low-temperature air enters the main heat exchanger 41 to cool the raw material air, reheated to ambient temperature and then discharged from the cold box as the regeneration gas of the molecular sieve purifier 30.

[0024] In the embodiment, the expansion end of the expander 60 is arranged in the cold box 40, the increase end is arranged outside the cold box 40, and the cooler 70 connected with the increase end of the expander 60 is further arranged outside the cold box 40, the nitrogen gas is cooled through the cooler 70 after being pressurized through the increase end of the expander 60 and then output as product nitrogen gas, so that the output requirement of the product is met.

[0025] The molecular sieve purifier 30 is further provided with the muffler 90 connected therewith, and the muffler 90 is connected with the expansion end of the expander 60 through the main heat exchanger 41, so that noise is reduced through the muffler 90 when the regeneration gas is discharged.

[0026] The cold box 40 is further provided with the residual liquid evaporator 80, and the residual liquid evaporator 80 is connected with the high-pressure rectification tower 42, the low-pressure rectification tower 43, the main condensation evaporator 44 and the auxiliary condensation evaporator 45 respectively. The low-temperature liquid generated in the operation process of the high-pressure rectification tower 42, the low-pressure rectification tower 43, the main condensation evaporator 44 and the auxiliary condensation evaporator 45 can be gasified through the residual liquid evaporator 80 and then discharged to the atmospheric environment.

[0027] In summary, the novel double-tower rectification high-extraction-rate energy-saving nitrogen production device has high nitrogen extraction rate, relatively simple structure, small land occupation of the rectification tower cold box and low operation energy consumption of the device.

[0028] The basic principle, main features and advantages of the utility model are shown and described. It should be understood by those skilled in the art that the utility model is not limited by the above embodiments, and the above embodiments and the description in the specification only illustrate the principle of the utility model, and various changes and improvements can be made to the utility model without departing from the spirit and scope of the utility model, and these changes and improvements all fall within the scope of the utility model claimed. The scope of protection of the utility model is defined by the appended claims and their equivalents.

Claims

1. A novel double-tower distillation high-extraction-rate energy-saving nitrogen production device, comprising an air compressor (10), a pre-cooling unit (20), a molecular sieve purifier (30) and a cold box (40) connected in sequence, characterized in that: The cold box (40) is provided with a main heat exchanger (41), a high-pressure rectifying tower (42), a low-pressure rectifying tower (43), a main condensing evaporator (44) and an auxiliary condensing evaporator (45), and further comprises an expander (60), wherein, The main heat exchanger (41) is connected with the molecular sieve purifier (30), the high-pressure rectifying tower (42), the low-pressure rectifying tower (43), the auxiliary condensing evaporator (45) and the expander (60); The high-pressure rectifying tower (42) is connected with the main condensing evaporator (44) and the low-pressure rectifying tower (43); The low-pressure rectifying tower (43) is connected with the main condensing evaporator (44) and the auxiliary condensing evaporator (45); The main condensing evaporator (44) is connected with the auxiliary condensing evaporator (45).

2. A novel double-tower rectification high-extraction-rate energy-saving nitrogen production device according to claim 1, characterized in that: The cold box (40) is further provided with a supercooler (46), which is connected with the main heat exchanger (41), the high-pressure rectifying tower (42) and the auxiliary condensing evaporator (45).

3. A new type of double-tower rectification high-extraction-rate energy-saving nitrogen production device according to claim 1 or 2, characterized in that: The expansion end of the expander (60) is arranged in the cold box (40), the increasing end is arranged outside the cold box (40), and the cold box (40) is further provided with a cooler (70) connected with the increasing end of the expander (60).

4. The novel double-tower rectification high-extraction-rate energy-saving nitrogen production device according to claim 3, characterized in that: The expansion end of the expander (60) is connected with the molecular sieve purifier (30) through the main heat exchanger (41).

5. The novel double-tower rectification high-extraction-rate energy-saving nitrogen production device according to claim 4, characterized in that: The molecular sieve purifier (30) is further provided with a silencer (90) connected therewith, and the silencer (90) is connected with the expansion end of the expander (60) through the main heat exchanger (41).

6. The novel double-tower rectification high-extraction-rate energy-saving nitrogen production device according to claim 5, characterized in that: The cold box (40) is further provided with a residual liquid evaporator (80), which is connected with the high-pressure rectifying tower (42), the low-pressure rectifying tower (43), the main condensing evaporator (44) and the auxiliary condensing evaporator (45) respectively.

7. The novel double-tower rectification high-extraction-rate energy-saving nitrogen production device according to claim 1, characterized in that: The front end of the air compressor (10) is further connected with an air filter (50).

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