CN115751840B - Variable working condition device and variable working condition process - Google Patents
Variable working condition device and variable working condition process Download PDFInfo
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- CN115751840B CN115751840B CN202211282820.5A CN202211282820A CN115751840B CN 115751840 B CN115751840 B CN 115751840B CN 202211282820 A CN202211282820 A CN 202211282820A CN 115751840 B CN115751840 B CN 115751840B
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
- F25J3/00—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification
- F25J3/02—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream
- F25J3/04—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream for air
- F25J3/04248—Generation of cold for compensating heat leaks or liquid production, e.g. by Joule-Thompson expansion
- F25J3/04284—Generation of cold for compensating heat leaks or liquid production, e.g. by Joule-Thompson expansion using internal refrigeration by open-loop gas work expansion, e.g. of intermediate or oxygen enriched (waste-)streams
- F25J3/0429—Generation of cold for compensating heat leaks or liquid production, e.g. by Joule-Thompson expansion using internal refrigeration by open-loop gas work expansion, e.g. of intermediate or oxygen enriched (waste-)streams of feed air, e.g. used as waste or product air or expanded into an auxiliary column
- F25J3/04303—Lachmann expansion, i.e. expanded into oxygen producing or low pressure column
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
- F25J3/00—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification
- F25J3/02—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream
- F25J3/04—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream for air
- F25J3/04248—Generation of cold for compensating heat leaks or liquid production, e.g. by Joule-Thompson expansion
- F25J3/04375—Details relating to the work expansion, e.g. process parameter etc.
- F25J3/04393—Details relating to the work expansion, e.g. process parameter etc. using multiple or multistage gas work expansion
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
- F25J3/00—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification
- F25J3/02—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream
- F25J3/04—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream for air
- F25J3/04406—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream for air using a dual pressure main column system
- F25J3/04412—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream for air using a dual pressure main column system in a classical double column flowsheet, i.e. with thermal coupling by a main reboiler-condenser in the bottom of low pressure respectively top of high pressure column
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
- F25J3/00—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification
- F25J3/02—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream
- F25J3/04—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream for air
- F25J3/04763—Start-up or control of the process; Details of the apparatus used
- F25J3/04769—Operation, control and regulation of the process; Instrumentation within the process
- F25J3/04812—Different modes, i.e. "runs" of operation
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- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Mechanical Engineering (AREA)
- Thermal Sciences (AREA)
- General Engineering & Computer Science (AREA)
- Separation By Low-Temperature Treatments (AREA)
Abstract
The invention discloses a variable working condition device and a variable working condition process. The variable working condition process comprises the following steps of: feeding: purified air input; heat exchange: the partially purified air is refrigerated by a first expander or a second expander and is used as a cold source; the rest purified air exchanges heat through the main heat exchanger and is used as a heat source; separating: the purified air is separated into nitrogen, dirty gas and liquid oxygen in a rectifying tower; and (3) outputting: and respectively conveying nitrogen, dirty gas and liquid oxygen to the outside. The variable working condition device and the variable working condition process are provided with two expansion machines, one of the two expansion machines is large in redundancy quantity adjusting range, the other of the two expansion machines is small in redundancy quantity under normal conditions, the other of the two expansion machines is large in redundancy quantity under abnormal conditions (when the supply is larger than the demand), the adjusting range of the other of the two expansion machines is larger, and the two expansion machines can operate with relatively lower power to reduce energy consumption.
Description
Technical Field
The invention belongs to the technical field of air separation, and particularly relates to a variable working condition device and a variable working condition process.
Background
The air separation device is a device for separating air and obtaining high-purity industrial gases such as oxygen, nitrogen, argon and the like, and is widely applied to various industrial fields such as petroleum, chemical industry, metallurgy, electronics, energy, aerospace, food and beverage, medical care and the like. The obtained oxygen, nitrogen and argon products have very wide application in national economy of one country.
With the progress and development of industrial technology, oxygen-enriched smelting technology is increasingly widely used in nonferrous metal smelting technology, and enterprises using oxygen resources on a large scale have to face the problem of high oxygen release rate. The electric energy waste caused by the fact that a large amount of oxygen is discharged by oxygen fluctuation in the metallurgical industry and the safety problem possibly caused by the fact that a large amount of oxygen is discharged are prominent problems of oxygen factories in the metallurgical industry. How to solve the problem is one of important factors related to nonferrous smelting processing cost and enterprise economic benefit.
Disclosure of Invention
The invention aims to provide a variable working condition device and a variable working condition process, which are used for solving the problems in the prior art.
In order to achieve the above purpose, the present invention adopts the following technical scheme:
the invention provides a variable working condition device, which comprises a first expander, a second expander, a main heat exchanger, an upper tower, a main cooling tower and a lower tower, wherein an air inlet pipe, a lower tower connecting pipe and an upper tower connecting pipe are arranged on the main heat exchanger;
the upper tower, the main cooling tower and the lower tower form a rectifying tower, the upper tower is connected with the main heat exchanger through an upper tower connecting pipe, the lower tower is connected with the main heat exchanger through a lower tower connecting pipe, a liquid oxygen output pipe and a liquid nitrogen delivery pipe are arranged at the bottom of the upper tower, a subcooler is arranged on the liquid nitrogen delivery pipe, the liquid oxygen output pipe is connected with an oxygen device or a storage tank, and a nitrogen output pipe and a sewage output pipe are arranged at the top of the upper tower;
the redundancy of the first expander is larger than that of the second expander, and the first expander and the second expander work alternately to adapt to different oxygen consumption demands.
In one possible design, the liquid nitrogen delivery pipe comprises a connecting pipe and a liquid nitrogen delivery pipe, wherein the connecting pipe is communicated with the subcooler and the main cooler, the subcooler is provided with a liquid nitrogen input pipe, and a liquid inlet of the liquid nitrogen delivery pipe is communicated with the connecting pipe.
In one possible design, the main heat exchanger, upper column, main cooling, lower column, and subcooler are of a type compatible with the first expander and the second expander.
In one possible design, the outlet pipe comprises a main pipe and two branch pipes, one end of the main pipe is communicated with the upper tower connecting pipe, and the other end of the main pipe is respectively communicated with the first expander and the second expander through the branch pipes.
In one possible design, a nitrogen heat exchanger is arranged on the nitrogen output pipe; the main heat exchanger is provided with a dirty gas discharge pipe, and the dirty gas output pipe is communicated with the dirty gas discharge pipe through the main heat exchanger.
In a second aspect, the invention provides a variable working condition process based on the variable working condition device, which comprises the following steps:
feeding: purified air input;
heat exchange: the partially purified air is refrigerated by a first expander or a second expander to be used as a cold source; the rest purified air exchanges heat through the main heat exchanger to be used as a heat source;
separating: the purified air is separated into oxygen, nitrogen, dirty nitrogen and liquid oxygen in a rectifying tower;
and (3) outputting: oxygen, nitrogen, dirty gas and liquid oxygen are respectively delivered outwards;
the redundancy of the first expander is larger than that of the second expander, and the first expander and the second expander work alternately to change the gas and liquid quantity output outwards.
In one possible design, in the step feed: the purified air input into the first expander or the second expander is first purified air, and the purified air input into the main heat exchanger is second purified air.
In one possible design, in the step heat exchange:
the first purified air is input into the main heat exchanger after passing through the pressurizing end of the first expander or the pressurizing end of the second expander, and is subjected to heat exchange with the second purified air;
and the first purified air is returned to the expansion end of the first expander or the expansion end of the second expander after heat exchange, and is conveyed to the upper tower after expansion.
In one possible design, during step separation, liquid nitrogen is replenished through a subcooler to increase reflux;
a nitrogen heat exchanger is arranged on the nitrogen output pipe; the main heat exchanger is provided with a dirty gas discharge pipe, and the dirty gas output pipe is communicated with the dirty gas discharge pipe through the main heat exchanger;
in the step output: cooling nitrogen by a nitrogen heat exchanger and discharging; the sewage gas is discharged after heat exchange by the main heat exchanger.
In one possible design, when the first expander is operated in place of the second expander, the respective yields of liquid oxygen and liquid nitrogen are increased, excess liquid oxygen is delivered to the storage tank via the liquid oxygen delivery pipe, and excess liquid nitrogen is delivered and stored via the liquid nitrogen delivery pipe.
The beneficial effects are that:
the variable working condition device is characterized in that a second expander is arranged on the basis of a single expander, the redundancy quantity adjusting range of one of the two expanders is large, any expander can be selected for use based on the second expander, the one with smaller redundancy quantity is normally used, the one with larger redundancy quantity is abnormally used (when the supply is larger than the demand), the adjusting range of the one with larger redundancy quantity is larger, and the variable working condition device can operate with relatively lower power so as to reduce energy consumption.
Based on the method, the variable working condition process adopts a simple method, solves the problems of high energy consumption, high flow of the expander, partial expansion amount sharing of the hot-end expander and the like of the existing air separation device, greatly increases the controllability of an air separation system, effectively reduces the oxygen release amount, can reduce the energy consumption, reduces the electric energy waste by more than 10 percent, and can avoid the unsafe hidden trouble caused by oxygen release. Meanwhile, the yield of liquid oxygen or liquid nitrogen is increased, the liquid oxygen can be sold out to increase the income of enterprises, and the liquid oxygen product can be stored for emergency use.
Drawings
FIG. 1 is a schematic diagram of a variable operating mode device.
In the figure:
1. a first expander; 2. a second expander; 3. a main heat exchanger; 4. loading on a tower; 5. main cooling; 6. lower tower; 7. an air intake pipe; 8. a lower tower connecting pipe; 9. a tower connecting pipe; 10. a first air inlet pipe; 11. a second air inlet pipe; 12. an air outlet pipe; 121. a main pipe; 122. a branch pipe; 13. an air bypass valve; 14. a liquid oxygen delivery tube; 15. a liquid nitrogen delivery pipe; 151. a connecting pipe; 152. a liquid nitrogen output pipe; 16. a subcooler; 17. a nitrogen output pipe; 18. a dirty gas output pipe; 19. a nitrogen heat exchanger; 20. a dirty gas discharge pipe; 21. liquid nitrogen input pipe.
Detailed Description
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the present invention will be briefly described below with reference to the accompanying drawings and the description of the embodiments or the prior art, and it is obvious that the following description of the structure of the drawings is only some embodiments of the present invention, and other drawings can be obtained according to these drawings without inventive effort to a person skilled in the art. It should be noted that the description of these examples is for aiding in understanding the present invention, but is not intended to limit the present invention.
In the prior art, the power of the air separation unit is fixed and can only be adjusted within a small range. Based on this, when the oxygen consumption fluctuates, and when the oxygen consumption greatly increases, the conventional air separation unit can be kept working, and the gap between the actual oxygen consumption and the oxygen supply can be made up by other technical means.
However, when the oxygen consumption is greatly reduced, the capacity of the existing air separation plant cannot be reduced due to limited regulation capacity, the produced oxygen amount is kept relatively constant, but the actual oxygen consumption is greatly reduced, so that the condition that the oxygen supply amount is larger than the oxygen consumption occurs in actual production, redundant oxygen is usually directly discharged into the atmosphere in the prior art, the problem of high oxygen release is caused, and further, a large amount of oxygen air defense increases the safety risk of the area nearby a factory, so that the safety production is not facilitated.
Meanwhile, compared with the electric energy consumed by the production of the actual oxygen consumption, the existing air separation unit which keeps full-power operation has the problem of overlarge energy consumption, the energy consumption is relatively high, and the production cost is increased.
Aiming at the problems existing in the prior art, the variable working condition device is provided with a second expansion machine on the basis of a single expansion machine, the redundancy quantity adjusting range of one of the two expansion machines is large, any expansion machine can be selected for use based on the variable working condition device, one with small redundancy quantity is normally used, one with large redundancy quantity is abnormally used (when the supply is larger than the demand), the adjusting range of the one with large redundancy quantity is larger, and the variable working condition device can operate with relatively lower power so as to reduce energy consumption.
Based on the method, the variable working condition process adopts a simple method, solves the problems of high energy consumption, high flow of the expander, partial expansion amount sharing of the hot-end expander and the like of the existing air separation device, greatly increases the controllability of an air separation system, effectively reduces the oxygen release amount, can reduce the energy consumption, reduces the electric energy waste by more than 10 percent, and can avoid the unsafe hidden trouble caused by oxygen release. Meanwhile, the yield of liquid oxygen or liquid nitrogen is increased, the liquid oxygen can be sold out to increase the income of enterprises, and the liquid oxygen product can be stored for emergency use.
Specifically, the fire disaster is easily caused by the large amount of oxygen and the dyspnea and even asphyxia of people are easily caused by the large amount of nitrogen, so that the amount of oxygen is effectively reduced and the safety of production is improved. The water and electricity waste is reduced, the development concept of energy conservation and emission reduction is met, and the benefit of a company is improved; the liquid oxygen is convenient to store, can be sold out, can be used for subsequent air supply, and is flexible to use. In the prior art, an external liquefying device is mostly adopted to treat redundant oxygen and nitrogen, so that additional investment of land, equipment and manpower is required to be increased, the production cost is greatly increased, and the problem is effectively avoided.
Example 1:
as shown in fig. 1, in a first aspect, the present invention provides a variable working condition device, which includes a first expander 1, a second expander 2, a main heat exchanger 3, an upper tower 4, a main cooling 5 and a lower tower 6, wherein the main heat exchanger 3 is provided with an air inlet pipe 7, a lower tower connecting pipe 8 and an upper tower connecting pipe 9, the first expander 1 is connected with a first air inlet pipe 10, the second expander 2 is provided with a second air inlet pipe 11, the first expander 1 and the second expander 2 are both communicated with the lower tower connecting pipe 8 through an air outlet pipe 12, and two ends of the connection part of the air outlet pipe 12 and the lower tower connecting pipe 8 are respectively provided with an air bypass valve 13;
the upper tower 4, the main cooling 5 and the lower tower 6 form a rectifying tower, the upper tower 4 is connected with the main heat exchanger 3 through an upper tower connecting pipe 9, the lower tower 6 is connected with the main heat exchanger 3 through a lower tower connecting pipe 8, a liquid oxygen output pipe 14 and a liquid nitrogen delivery pipe 15 are arranged at the bottom of the upper tower 4, a subcooler 16 is arranged on the liquid nitrogen delivery pipe 15, the liquid oxygen output pipe 14 is connected with an oxygen-utilizing device or a storage tank, and a nitrogen output pipe 17 and a sewage output pipe 18 are arranged at the top of the upper tower 4;
the redundancy of the first expander 1 is larger than that of the second expander 2, and the first expander 1 and the second expander 2 alternately work to adapt to different oxygen consumption requirements.
The redundancy of the first expander 1 is large, the redundancy of the second expander 2 is small, the second expander 2 is used under normal conditions, and when the supply-demand relationship is changed, the first expander 1 is used, so that the flexibility of use is improved. The main heat exchanger 3 is adapted to take over heat exchange between the process air and the return gas, cooling the process air below its critical temperature to liquefy it, for use as a cold source in the rectifying column. Further, in the working condition changing device, the processing air and the back flow air are both the input purified air, namely, part of the purified air (namely, the first purified air, hereinafter referred to as first purified air) is input into the first expander 1 or the second expander 2, and is sequentially conveyed to the main heat exchanger 3 through the air outlet pipe 12 and the upper tower connecting pipe 9 after being pressurized, the rest of the purified air (namely, the second purified air, hereinafter referred to as second purified air) is input into the main heat exchanger 3, and then the first purified air and the second purified air exchange heat in the main heat exchanger 3, the first purified air releases heat and cools to be used as a cold source, and the second purified air absorbs heat and heats to be used as a heat source.
The upper tower 4, the main cooling 5 and the lower tower 6 form a rectifying tower, the first purified air is a cold source, the first purified air is conveyed to the upper tower 4 and falls down, the second purified air is a heat source, the second purified air is conveyed to the lower tower 6 and rises, the rising steam and the falling liquid are subjected to heat exchange to realize separation of nitrogen and oxygen, and four products of gas nitrogen, liquid oxygen and sewage gas are obtained, and the products can be used in different aspects after being collected respectively, so that the comprehensive benefit is improved.
The air bypass valve 13 is used for limiting the on-off of the upper tower connecting pipe 9 so as to ensure that the flow direction of the first purified air accords with the design, and the flow route of the first purified air is the first expander 1 or the second expander 2-the main heat exchanger 3-the first expander 1 or the second expander 2-the upper tower 4, wherein the first purified air flows through the pressurizing end of the first expander 1 or the second expander 2 for the first time and flows through the expanding end of the first expander 1 or the second expander 2 for the second time.
In operation, taking the first expander 1 as an example, the first purified air is input into the first expander 1 through the first air inlet pipe 10, and the first purified air enters the pressurizing end of the first expander 1, and flows into the main heat exchanger 3 through the air outlet pipe 12 and the upper tower connecting pipe 9 after being pressurized. The second purified air is input into the main heat exchanger 3 through the air inlet pipe 7, heat exchange is carried out between the first purified air and the first purified air after the first purified air enters the main heat exchanger 3, the first purified air is returned to the expansion end of the first expander 1 after heat release and temperature reduction, and the second purified air is input into the lower tower 6 through the lower tower connecting pipe 8 after heat absorption and temperature rise. The first purified air is expanded in the first expander 1 and then fed into the upper column 4 through the upper column connecting pipe 9. Meanwhile, when the first purified air flows, the two air bypass valves 13 are noticed to be opened and closed so as to ensure that the air flows correctly.
After the first purified air and the second purified air are both conveyed into the rectifying tower, a cold source and a heat source in the rectifying tower are complete, and the purified air is separated in the rectifying tower, wherein the working principle of the rectifying tower is common knowledge in the field and is not repeated herein. After separation, the gas nitrogen is output through a nitrogen output pipe 17, the sewage gas is output through a sewage gas output pipe 18, the liquid oxygen is output through a liquid oxygen output pipe 14, and the liquid nitrogen is output through a liquid nitrogen delivery pipe 15, or the liquid nitrogen is delivered to a subcooler 16 and flows back to the upper tower 4, so that the volume of the reflux liquid is increased.
In a possible implementation manner, the liquid nitrogen delivery pipe 15 includes a connecting pipe 151 and a liquid nitrogen output pipe 152, the connecting pipe 151 is communicated with the subcooler 16 and the main cooling 5, the subcooler 16 is provided with a liquid nitrogen input pipe 21, and a liquid inlet of the liquid nitrogen output pipe 152 is communicated with the connecting pipe 151. Based on the above design, the connecting pipe 151 is used for the reciprocating flow of liquid nitrogen between the rectifying tower and the subcooler 16, so as to refrigerate the liquid nitrogen through the subcooler 16, avoid the gasification of the liquid nitrogen, and ensure the volume of the reflux liquid in the upper tower 4. The liquid nitrogen output pipe 152 is used for outputting liquid nitrogen outwards, namely outputting liquid nitrogen products outwards when the supply is greater than the demand, and reducing the volume of reflux liquid in the upper tower 4 so as to reduce the yield of the rest products.
In one possible implementation, the main heat exchanger 3, the upper column 4, the main cooling 5, the lower column 6 and the subcooler 16 are of a type compatible with the first expander 1 and the second expander 2. It is easy to understand that in the variable working condition device, the refrigeration performance is changed by the alternate operation of the first expander 1 and the second expander 2, and the main heat exchanger 3, the upper tower 4, the main cooling 5, the lower tower 6 and the subcooler 16 are also adaptively selected, that is, the upper tower 4 and the lower tower 6 are subjected to variable working condition calculation design according to the oxygen demand in advance, so that the upper tower 4 and the lower tower 6 can be adapted to normally produce gaseous oxygen and nitrogen, and also adapt to produce more liquid oxygen or liquid nitrogen than the conventional production, and the gas-liquid ratio adjustment range of the rectifying tower is large; while an adaptively compatible retrofit main heat exchanger 3 and subcooler 16 is performed.
In one possible implementation, as shown in fig. 1, the air outlet pipe 12 includes a main pipe 121 and two branch pipes 122, one end of the main pipe 121 is connected to the upper tower connection pipe 9, and the other end of the main pipe 121 is connected to the first expander 1 and the second expander 2 through the branch pipes 122, respectively. Based on the above design, the branch pipe 122 not only plays a role of connection, but also can be appropriately extended to be adapted to the distance between the first expander 1 and the second expander 2 to meet the installation requirements of the first expander 1 and the second expander 2.
In one possible implementation, a nitrogen heat exchanger 19 is provided on the nitrogen outlet pipe 17. Based on the above design, the nitrogen heat exchanger 19 is used for refrigerating the nitrogen output outwards, the liquefied nitrogen is liquefied into liquid nitrogen, and then the liquid nitrogen can be input into the subcooler 16 through the liquid nitrogen input pipe 21 to form reflux liquid for the upper tower 4, so that the reflux liquid is supplemented. In other words, the application of the gas nitrogen is expanded, the reflux times are increased, and the separation purity is improved.
In one possible implementation, the main heat exchanger 3 is provided with a dirty gas outlet pipe 20, and the dirty gas outlet pipe 18 communicates with the dirty gas outlet pipe 20 via the main heat exchanger 3. Based on the design scheme, the second purified air is heated by utilizing the heat of the sewage gas, so that the energy is fully utilized, and the waste is reduced.
Example 2:
the embodiment introduces a variable working condition process based on the variable working condition device on the basis of embodiment 1, wherein the variable working condition process comprises the following steps:
s100 feeding: purified air input; and the purified air input into the first expander 1 or the second expander 2 is first purified air, and the purified air input into the main heat exchanger 3 is second purified air, so as to describe the flow direction of the purified air.
S200, heat exchange: the partially purified air is cooled by the first expander 1 or the second expander 2 to be used as a cold source; the remaining purified air is heat exchanged via the main heat exchanger 3 to be used as a heat source.
Specifically, S200 heat exchange includes:
s201: the first purified air is fed into the main heat exchanger 3 through the pressurizing end of the first expander 1 or the pressurizing end of the second expander 2, and is subjected to heat exchange with the second purified air.
S202: the first purified air is returned to the expansion end of the first expander 1 or the expansion end of the second expander 2 after heat exchange, and is delivered to the upper tower 4 after expansion.
Through step S201 and step S202, not only the heating of the second purified air can be achieved by the heat of the purified air itself to form a heat source, but also the temperature of the first purified air can be greatly reduced to form a cold source. Based on the above, the energy input is reduced, so that the purpose of reducing the energy consumption is achieved.
S300, separation: the purified air is separated into oxygen, nitrogen, dirty nitrogen and liquid oxygen in a rectifying column.
In step S300, liquid nitrogen is replenished through the subcooler 16 to increase the reflux liquid. Based on this, the sufficient reflux liquid provides the necessary flow for each plate, a necessary condition for establishing a normal concentration profile for each plate and maintaining continuous stable operation of the whole column.
S400 output: oxygen, nitrogen, dirty gas and liquid oxygen are respectively delivered to the outside.
The nitrogen output pipe 17 is provided with a nitrogen heat exchanger 19; the main heat exchanger 3 is provided with a dirty gas discharge pipe 20, and a dirty gas output pipe 18 is communicated with the dirty gas discharge pipe 20 through the main heat exchanger 3; in step S400: the nitrogen is discharged after being cooled by a nitrogen heat exchanger 19; the dirty gas is discharged after heat exchange by the main heat exchanger 3. Based on the method, different products flow out from different pipelines to obtain different kinds of products in a classified way, so as to treat and utilize the products respectively, and achieve the purpose of improving comprehensive benefits.
Wherein the redundancy of the first expander 1 is greater than that of the second expander 2, and the first expander 1 and the second expander 2 alternately operate to change the amount of gas and liquid output to the outside.
Namely, when the second expander 2 works, the redundant quantity of the second expander 2 meets the oxygen supply requirement in normal production, and the second expander 2 works normally. When the supply and demand relation is changed, when the first expander 1 is used for replacing the second expander 2, the respective yields of liquid oxygen and liquid nitrogen are increased, the surplus liquid oxygen is conveyed to the storage tank through the liquid oxygen output pipe 14, and the surplus liquid nitrogen is output and stored through the liquid nitrogen conveying pipe 15. Based on this, on the basis of meeting the oxygen supply requirement, the redundant liquid oxygen can be stored in a storage tank for emergency use.
Finally, it should be noted that: the foregoing description is only of the preferred embodiments of the invention and is not intended to limit the scope of the invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (9)
1. The variable working condition device is characterized by comprising a first expander (1), a second expander (2), a main heat exchanger (3), an upper tower (4), a main cooler (5) and a lower tower (6), wherein an air inlet pipe (7), a lower tower connecting pipe (8) and an upper tower connecting pipe (9) are arranged on the main heat exchanger (3), a first air inlet pipe (10) is connected to the first expander (1), a second air inlet pipe (11) is arranged on the second expander (2), the first expander (1) and the second expander (2) are both communicated with the lower tower connecting pipe (8) through an air outlet pipe (12), and an air bypass valve (13) is respectively arranged at two ends of a joint of the air outlet pipe (12) and the lower tower connecting pipe (8);
the upper tower (4), the main cooling (5) and the lower tower (6) form a rectifying tower, the upper tower (4) is connected with the main heat exchanger (3) through an upper tower connecting pipe (9), the lower tower (6) is connected with the main heat exchanger (3) through a lower tower connecting pipe (8), a liquid oxygen output pipe (14) and a liquid nitrogen delivery pipe (15) are arranged at the bottom of the upper tower (4), a subcooler (16) is arranged on the liquid nitrogen delivery pipe (15), the liquid oxygen output pipe (14) is connected with an oxygen-utilizing device or a storage tank, and a nitrogen output pipe (17) and a sewage output pipe (18) are arranged at the top of the upper tower (4);
the redundancy of the first expander (1) is larger than that of the second expander (2), and the first expander (1) and the second expander (2) work alternately to adapt to different oxygen consumption demands;
the liquid nitrogen delivery pipe (15) comprises a connecting pipe (151) and a liquid nitrogen output pipe (152), the connecting pipe (151) is communicated with the subcooler (16) and the main cooler (5), the subcooler (16) is provided with a liquid nitrogen input pipe (21), and a liquid inlet of the liquid nitrogen output pipe (152) is communicated with the connecting pipe (151);
when the second expander (2) works, the redundant quantity of the second expander (2) meets the oxygen supply requirement in normal production, and the second expander (2) works normally; when the supply and demand relation is changed, when the first expander (1) is used for replacing the second expander (2), the respective yields of liquid oxygen and liquid nitrogen are increased, the redundant liquid oxygen is conveyed to a storage tank through a liquid oxygen output pipe (14), and the redundant liquid nitrogen is output and stored through a liquid nitrogen conveying pipe (15).
2. The variable working condition device according to claim 1, wherein the main heat exchanger (3), the upper tower (4), the main cooling (5), the lower tower (6) and the subcooler (16) are of a type compatible with the first expander (1) and the second expander (2).
3. The variable working condition device according to claim 1, wherein the air outlet pipe (12) comprises a main pipe (121) and two branch pipes (122), one end of the main pipe (121) is communicated with the upper tower connecting pipe (9), and the other end of the main pipe (121) is respectively communicated with the first expander (1) and the second expander (2) through the branch pipes (122).
4. The variable working condition device according to claim 1, characterized in that a nitrogen heat exchanger (19) is arranged on the nitrogen output pipe (17);
the main heat exchanger (3) is provided with a waste gas discharge pipe (20), and a waste gas output pipe (18) is communicated with the waste gas discharge pipe (20) through the main heat exchanger (3).
5. A variable operating condition process based on the variable operating condition device according to any one of claims 1 to 4, characterized by comprising the steps of:
feeding: purified air input;
heat exchange: the partially purified air is refrigerated by a first expander (1) or a second expander (2) to be used as a cold source; the rest purified air exchanges heat through the main heat exchanger (3) to be used as a heat source;
separating: the purified air is separated into oxygen, nitrogen, dirty nitrogen and liquid oxygen in a rectifying tower;
and (3) outputting: oxygen, nitrogen, dirty gas and liquid oxygen are respectively delivered outwards;
the redundancy of the first expander (1) is larger than that of the second expander (2), and the first expander (1) and the second expander (2) work alternately to change the gas and liquid amounts output outwards.
6. The variable duty process of claim 5, wherein in the step of feeding: the purified air input into the first expander (1) or the second expander (2) is first purified air, and the purified air input into the main heat exchanger (3) is second purified air.
7. The variable duty process of claim 6, wherein in the step of heat exchanging:
the first purified air is input into the main heat exchanger (3) after passing through the pressurizing end of the first expander (1) or the pressurizing end of the second expander (2), and is subjected to heat exchange with the second purified air;
the first purified air is returned to the expansion end of the first expander (1) or the expansion end of the second expander (2) after heat exchange, and the first purified air is delivered to the upper tower (4) after expansion.
8. The variable duty process of claim 5, wherein during step separation, liquid nitrogen is supplemented by a subcooler (16) to increase reflux;
a nitrogen heat exchanger (19) is arranged on the nitrogen output pipe (17); the main heat exchanger (3) is provided with a sewage gas discharge pipe (20), and a sewage gas output pipe (18) is communicated with the sewage gas discharge pipe (20) through the main heat exchanger (3);
in the step output: the nitrogen is discharged after being cooled by a nitrogen heat exchanger (19); the dirty gas is discharged after heat exchange by the main heat exchanger (3).
9. The variable working condition process according to claim 5, wherein when the first expander (1) is operated in place of the second expander (2), the respective yields of liquid oxygen and liquid nitrogen are increased, the surplus liquid oxygen is conveyed to the storage tank through the liquid oxygen output pipe (14), and the surplus liquid nitrogen is output and stored through the liquid nitrogen conveying pipe (15).
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| US6082137A (en) * | 1998-03-24 | 2000-07-04 | The Boc Group Plc | Separation of air |
| JP2001116449A (en) * | 1999-10-12 | 2001-04-27 | Kobe Steel Ltd | Air separator and operating method therefor |
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| CN115077140A (en) * | 2021-03-16 | 2022-09-20 | 浙江雪波蓝科技有限公司 | Rankine cycle system, Rankine-refrigeration cycle system, and refrigerator car |
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2022
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Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6082137A (en) * | 1998-03-24 | 2000-07-04 | The Boc Group Plc | Separation of air |
| JP2001116449A (en) * | 1999-10-12 | 2001-04-27 | Kobe Steel Ltd | Air separator and operating method therefor |
| WO2017101775A1 (en) * | 2015-12-16 | 2017-06-22 | 新疆天辰深冷技术有限公司 | Externally-cooled low-purity oxygen air separation system and method |
| CN108731379A (en) * | 2018-07-24 | 2018-11-02 | 杭州杭氧股份有限公司 | A kind of amount of liquid is adjustable and produces the air separation plant and production method of more specification oxygen products simultaneously |
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| CN115751840A (en) | 2023-03-07 |
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