CN110608583B - Pressure control method and device - Google Patents
Pressure control method and device Download PDFInfo
- Publication number
- CN110608583B CN110608583B CN201910862915.6A CN201910862915A CN110608583B CN 110608583 B CN110608583 B CN 110608583B CN 201910862915 A CN201910862915 A CN 201910862915A CN 110608583 B CN110608583 B CN 110608583B
- Authority
- CN
- China
- Prior art keywords
- nitrogen pipeline
- valve
- molecular sieve
- controlling
- nitrogen
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
- 238000000034 method Methods 0.000 title claims abstract description 33
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims abstract description 671
- 229910052757 nitrogen Inorganic materials 0.000 claims abstract description 332
- 239000002808 molecular sieve Substances 0.000 claims abstract description 136
- URGAHOPLAPQHLN-UHFFFAOYSA-N sodium aluminosilicate Chemical compound [Na+].[Al+3].[O-][Si]([O-])=O.[O-][Si]([O-])=O URGAHOPLAPQHLN-UHFFFAOYSA-N 0.000 claims abstract description 136
- 239000002699 waste material Substances 0.000 claims abstract description 126
- 238000010438 heat treatment Methods 0.000 claims abstract description 55
- 238000007664 blowing Methods 0.000 claims abstract description 42
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 39
- 238000000926 separation method Methods 0.000 claims abstract description 34
- 230000004913 activation Effects 0.000 claims description 11
- 239000010865 sewage Substances 0.000 claims description 3
- 230000001276 controlling effect Effects 0.000 description 46
- 238000001816 cooling Methods 0.000 description 13
- 238000004519 manufacturing process Methods 0.000 description 10
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 description 8
- 239000007789 gas Substances 0.000 description 8
- 229910001873 dinitrogen Inorganic materials 0.000 description 7
- 230000008929 regeneration Effects 0.000 description 6
- 238000011069 regeneration method Methods 0.000 description 6
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 4
- MYMOFIZGZYHOMD-UHFFFAOYSA-N Dioxygen Chemical compound O=O MYMOFIZGZYHOMD-UHFFFAOYSA-N 0.000 description 4
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 4
- 239000001569 carbon dioxide Substances 0.000 description 4
- 229910002092 carbon dioxide Inorganic materials 0.000 description 4
- 230000008569 process Effects 0.000 description 4
- 238000010586 diagram Methods 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 150000002829 nitrogen Chemical class 0.000 description 3
- 230000009467 reduction Effects 0.000 description 3
- 230000009466 transformation Effects 0.000 description 3
- 229910000831 Steel Inorganic materials 0.000 description 2
- 238000010521 absorption reaction Methods 0.000 description 2
- 229910052786 argon Inorganic materials 0.000 description 2
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 2
- 238000006243 chemical reaction Methods 0.000 description 2
- 239000000498 cooling water Substances 0.000 description 2
- 239000012073 inactive phase Substances 0.000 description 2
- 229910052742 iron Inorganic materials 0.000 description 2
- 239000007788 liquid Substances 0.000 description 2
- 239000001301 oxygen Substances 0.000 description 2
- 229910052760 oxygen Inorganic materials 0.000 description 2
- 238000005057 refrigeration Methods 0.000 description 2
- 239000010959 steel Substances 0.000 description 2
- 101100522111 Oryza sativa subsp. japonica PHT1-11 gene Proteins 0.000 description 1
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 1
- 230000009471 action Effects 0.000 description 1
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 230000000903 blocking effect Effects 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 230000018109 developmental process Effects 0.000 description 1
- 238000007599 discharging Methods 0.000 description 1
- 239000000428 dust Substances 0.000 description 1
- 238000004134 energy conservation Methods 0.000 description 1
- 238000005265 energy consumption Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000000605 extraction Methods 0.000 description 1
- 238000001914 filtration Methods 0.000 description 1
- 238000009434 installation Methods 0.000 description 1
- 239000000395 magnesium oxide Substances 0.000 description 1
- CPLXHLVBOLITMK-UHFFFAOYSA-N magnesium oxide Inorganic materials [Mg]=O CPLXHLVBOLITMK-UHFFFAOYSA-N 0.000 description 1
- AXZKOIWUVFPNLO-UHFFFAOYSA-N magnesium;oxygen(2-) Chemical compound [O-2].[Mg+2] AXZKOIWUVFPNLO-UHFFFAOYSA-N 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- -1 moisture Substances 0.000 description 1
- 239000012071 phase Substances 0.000 description 1
- 238000010926 purge Methods 0.000 description 1
- 230000001105 regulatory effect Effects 0.000 description 1
- 229920006395 saturated elastomer Polymers 0.000 description 1
- 229910052814 silicon oxide Inorganic materials 0.000 description 1
- KKCBUQHMOMHUOY-UHFFFAOYSA-N sodium oxide Chemical compound [O-2].[Na+].[Na+] KKCBUQHMOMHUOY-UHFFFAOYSA-N 0.000 description 1
- 229910001948 sodium oxide Inorganic materials 0.000 description 1
- 238000001179 sorption measurement Methods 0.000 description 1
- 239000012798 spherical particle Substances 0.000 description 1
- 238000005507 spraying Methods 0.000 description 1
Images
Classifications
-
- 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
- F25J3/04775—Air purification and pre-cooling
-
- 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
- F25J3/04006—Providing pressurised feed air or process streams within or from the air fractionation unit
- F25J3/04078—Providing pressurised feed air or process streams within or from the air fractionation unit providing pressurized products by liquid compression and vaporisation with cold recovery, i.e. so-called internal compression
- F25J3/0409—Providing pressurised feed air or process streams within or from the air fractionation unit providing pressurized products by liquid compression and vaporisation with cold recovery, i.e. so-called internal compression of oxygen
-
- 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
- F25J3/04151—Purification and (pre-)cooling of the feed air; recuperative heat-exchange with product streams
- F25J3/04157—Afterstage cooling and so-called "pre-cooling" of the feed air upstream the air purification unit and main heat exchange line
-
- 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
- F25J3/04151—Purification and (pre-)cooling of the feed air; recuperative heat-exchange with product streams
- F25J3/04163—Hot end purification of the feed air
- F25J3/04169—Hot end purification of the feed air by adsorption of the impurities
- F25J3/04181—Regenerating the adsorbents
-
- 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
-
- 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
- F25J3/04521—Coupling of the air fractionation unit to an air gas-consuming unit, so-called integrated processes
- F25J3/04563—Integration with a nitrogen consuming unit, e.g. for purging, inerting, cooling or heating
-
- 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
- F25J3/04781—Pressure changing devices, e.g. for compression, expansion, liquid pumping
-
- 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
- F25J3/04787—Heat exchange, e.g. main heat exchange line; Subcooler, external reboiler-condenser
-
- 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
- F25J2205/00—Processes or apparatus using other separation and/or other processing means
- F25J2205/30—Processes or apparatus using other separation and/or other processing means using a washing, e.g. "scrubbing" or bubble column for purification purposes
- F25J2205/32—Processes or apparatus using other separation and/or other processing means using a washing, e.g. "scrubbing" or bubble column for purification purposes as direct contact cooling tower to produce a cooled gas stream, e.g. direct contact after cooler [DCAC]
-
- 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
- F25J2205/00—Processes or apparatus using other separation and/or other processing means
- F25J2205/30—Processes or apparatus using other separation and/or other processing means using a washing, e.g. "scrubbing" or bubble column for purification purposes
- F25J2205/34—Processes or apparatus using other separation and/or other processing means using a washing, e.g. "scrubbing" or bubble column for purification purposes as evaporative cooling tower to produce chilled water, e.g. evaporative water chiller [EWC]
-
- 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
- F25J2215/00—Processes characterised by the type or other details of the product stream
- F25J2215/42—Nitrogen or special cases, e.g. multiple or low purity N2
-
- 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
- F25J2245/00—Processes or apparatus involving steps for recycling of process streams
- F25J2245/42—Processes or apparatus involving steps for recycling of process streams the recycled stream being nitrogen
-
- 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
- F25J2270/00—Refrigeration techniques used
- F25J2270/90—External refrigeration, e.g. conventional closed-loop mechanical refrigeration unit using Freon or NH3, unspecified external refrigeration
Landscapes
- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Mechanical Engineering (AREA)
- Thermal Sciences (AREA)
- General Engineering & Computer Science (AREA)
- Health & Medical Sciences (AREA)
- Emergency Medicine (AREA)
- Separation Of Gases By Adsorption (AREA)
Abstract
The embodiment of the invention provides a pressure control method and a pressure control device, which are applied to an air separation system, wherein the air separation system comprises the following components: a first pure nitrogen pipeline, a second pure nitrogen pipeline, a third pure nitrogen pipeline, a first waste nitrogen pipeline, a second waste nitrogen pipeline, a third waste nitrogen pipeline and a fourth waste nitrogen pipeline; the third pure nitrogen pipeline and the first waste nitrogen pipeline are connected with a nitrogen water tower, and the second waste nitrogen pipeline and the third waste nitrogen pipeline are connected with a molecular sieve; the method comprises the following steps: controlling the opening degree of a first valve on the first pure nitrogen pipeline to be 30-35%, and controlling the opening degree of a second valve on the second pure nitrogen pipeline to be 30-35%; when the molecular sieve is determined to be in a heating stage or a cold blowing stage, controlling a first opening of a third valve on a third pure nitrogen pipeline based on a preset upper tower pressure; the preset upper tower pressure is 36 KPa; and controlling a fourth valve on the first waste nitrogen pipeline to be closed, and controlling a sixth valve on the fourth waste nitrogen pipeline to be closed.
Description
Technical Field
The invention relates to the technical field of air separation rectification, in particular to a pressure control method and a pressure control device.
Background
The stability of the upper tower pressure in the air separation device is a necessary condition for the stability of the rectification working condition, the fluctuation of the upper tower pressure can cause the fluctuation of the whole rectification tower working condition, the purity of the product nitrogen is influenced, and the change of an argon enrichment area can be caused to further influence the extraction of argon fraction.
With the development of iron and steel enterprises, the demand of the iron and steel enterprises for pure nitrogen is increased by multiple times, and under the condition that the pure nitrogen yield of the existing air separation device can not meet the production demand, the oxygen and nitrogen yield is improved to more than 1:2 from 1:1 at the beginning of design by carrying out process technology transformation on the existing air separation device, so that the demand of the enterprises for the nitrogen consumption is ensured.
In the process of technological transformation, in order to reduce the transformation cost, the waste nitrogen pipeline and the pure nitrogen pipeline are exchanged, the pipe diameter of the pure nitrogen pipeline is increased, but the pipe diameter of the waste nitrogen pipeline is reduced. And the waste nitrogen is an important component in the regeneration process of the molecular sieve, and the reduction of the waste nitrogen can lead the pressure of a waste nitrogen pipeline to be lowered in the heating stage and the cold blowing stage of the molecular sieve, so that the required waste nitrogen flow is insufficient. In order to ensure the regeneration effect of the molecular sieve, the waste nitrogen is continuously extracted from the upper tower, so that the pressure fluctuation of the upper tower is caused, the purity of the nitrogen is reduced, and the quality of the nitrogen product is influenced.
Disclosure of Invention
Aiming at the problems in the prior art, the embodiment of the invention provides a pressure control method and a pressure control device, which are used for solving the technical problems that in the prior art, the nitrogen purity is reduced and the quality of a nitrogen finished product is influenced because the upper tower pressure fluctuation of an air separation device is caused by the reduction of the pipe diameter of a waste nitrogen pipeline.
The embodiment of the invention provides a pressure control method, which is applied to an air separation system, wherein the air separation system comprises the following steps: a first pure nitrogen pipeline, a second pure nitrogen pipeline, a third pure nitrogen pipeline, a first waste nitrogen pipeline, a second waste nitrogen pipeline, a third waste nitrogen pipeline and a fourth waste nitrogen pipeline; the third pure nitrogen pipeline and the first waste nitrogen pipeline are connected with a nitrogen water tower, and the second waste nitrogen pipeline and the third waste nitrogen pipeline are connected with a molecular sieve; the method comprises the following steps:
controlling the opening degree of a first valve on the first pure nitrogen pipeline to be 30-35%, and controlling the opening degree of a second valve on the second pure nitrogen pipeline to be 30-35%;
when the molecular sieve is determined to be in a heating stage or a cold blowing stage, controlling a first opening of a third valve on a third pure nitrogen pipeline based on a preset upper tower pressure; the preset upper tower pressure is 36 KPa;
and controlling a fourth valve on the first waste nitrogen pipeline to be closed, and controlling a sixth valve on the fourth waste nitrogen pipeline to be closed.
In the above scheme, the method further comprises:
when the molecular sieve is determined to be in the non-activation stage, controlling the opening degree of the fourth valve to be 40-50%, and adjusting the opening degree of the sixth valve based on the preset upper tower pressure;
controlling a second opening degree of the third valve based on nitrogen flow reserved in the cold box, wherein the reserved nitrogen flow is 50-55% of the total nitrogen amount;
and controlling a heating valve on the second waste nitrogen pipeline to be closed, and controlling a cold blowing valve on the third waste nitrogen pipeline to be closed.
In the above scheme, when the molecular sieve is in the heating stage or the cold blowing stage, the method further comprises:
and acquiring the actual pressure in the upper tower, and controlling the fourth valve to be opened if the actual pressure is higher than a preset maximum limit value.
In the above scheme, when the molecular sieve is in the heating stage, the method comprises: adjusting an opening of a heating valve on the second dirty nitrogen line based on a required amount of dirty nitrogen for the molecular sieve.
In the above scheme, when the molecular sieve is in the cold blowing stage, the method comprises: and adjusting the opening degree of a cold blow valve on the third waste nitrogen pipeline based on the required waste nitrogen amount of the molecular sieve.
The embodiment of the invention also provides a pressure control device, which is applied to an air separation system, wherein the air separation system comprises: a first pure nitrogen pipeline, a second pure nitrogen pipeline, a third pure nitrogen pipeline, a first waste nitrogen pipeline, a second waste nitrogen pipeline, a third waste nitrogen pipeline and a fourth waste nitrogen pipeline; the third pure nitrogen pipeline and the first waste nitrogen pipeline are connected with a nitrogen water tower, and the second waste nitrogen pipeline and the third waste nitrogen pipeline are connected with a molecular sieve; the device comprises:
the first control unit is used for controlling the opening degree of a first valve on the first pure nitrogen pipeline to be 30-35%
The second control unit is used for controlling the opening of a second valve on the second pure nitrogen pipeline to be 30-35%;
the third control unit is used for controlling the first opening of a third valve on the third pure nitrogen pipeline based on preset upper tower pressure when the molecular sieve is determined to be in the heating stage or the cold blowing stage; the preset upper tower pressure is 36 KPa;
the fourth control unit is used for controlling a fourth valve on the first sewage nitrogen pipeline to be closed;
and the fifth control unit is used for controlling a sixth valve on the fourth waste nitrogen pipeline to be closed.
In the above scheme, the apparatus further comprises: a sixth control unit and a seventh control unit;
when it is determined that the molecular sieve is in the inactive stage, the third control unit is further to: controlling a second opening degree of the third valve based on nitrogen flow reserved in the cold box, wherein the reserved nitrogen flow is 50-55% of the total nitrogen amount;
the fourth control unit is further configured to: controlling the opening of the fourth valve to be 40-50%;
the fifth control unit is further configured to: adjusting the opening degree of the sixth valve based on the preset upper tower pressure;
the sixth control unit is configured to: controlling a heating valve on the second waste nitrogen pipeline to close;
the seventh control unit is configured to: and controlling a cold blow valve on the third waste nitrogen pipeline to be closed.
In the foregoing solution, the fourth control unit is further configured to: and when the molecular sieve is in a heating stage or a cold blowing stage, acquiring the actual pressure in the upper tower, and if the actual pressure is higher than a preset maximum limit value, controlling the fourth valve to be opened.
In the foregoing solution, the sixth control unit is further configured to: adjusting an opening of a heating valve on the second dirty nitrogen line based on a desired amount of dirty nitrogen for the molecular sieve when the molecular sieve is in a heating stage.
In the foregoing solution, the seventh control unit is further configured to: and when the molecular sieve is in a cold blowing stage, adjusting the opening degree of a cold blowing valve on the third dirty nitrogen pipeline based on the dirty nitrogen amount required by the molecular sieve.
The embodiment of the invention provides a pressure control method and a pressure control device, which are applied to an air separation system, wherein the air separation system comprises the following components: a first pure nitrogen pipeline, a second pure nitrogen pipeline, a third pure nitrogen pipeline, a first waste nitrogen pipeline, a second waste nitrogen pipeline, a third waste nitrogen pipeline and a fourth waste nitrogen pipeline; the third pure nitrogen pipeline and the first waste nitrogen pipeline are connected with a nitrogen water tower, and the second waste nitrogen pipeline and the third waste nitrogen pipeline are connected with a molecular sieve; the method comprises the following steps: controlling the opening degree of a first valve on the first pure nitrogen pipeline to be 30-35%, and controlling the opening degree of a second valve on the second pure nitrogen pipeline to be 30-35%; when the molecular sieve is determined to be in a heating stage or a cold blowing stage, controlling a first opening of a third valve on a third pure nitrogen pipeline based on a preset upper tower pressure; the preset upper tower pressure is 36 KPa; controlling a fourth valve on the first waste nitrogen pipeline to be closed, and controlling a sixth valve on the fourth waste nitrogen pipeline to be closed; so, the molecular sieve is in heating stage or cold blowing stage, if the dirty nitrogen volume that needs increases, when extracting dirty nitrogen from last tower, then through the first aperture of the third valve on the control third pure nitrogen pipeline, suitably reduce the pure nitrogen volume that third pure nitrogen pipeline flowed out, and control the fourth valve on the first dirty nitrogen pipeline and close, the sixth valve on the control fourth dirty nitrogen pipeline is closed, reduce dirty nitrogen outflow, make the pressure of going up the tower remain at 36KPa all the time, just so can avoid the pressure of going up the tower to produce undulantly, and then avoid influencing the purity of nitrogen gas product, ensured nitrogen gas quality.
Drawings
Fig. 1 is a schematic structural diagram of an air separation system according to a first embodiment of the present invention;
FIG. 2 is a schematic diagram illustrating installation of a pure nitrogen pipeline and a waste nitrogen pipeline according to an embodiment of the present invention;
FIG. 3 is a schematic flow chart of a pressure control method according to an embodiment of the present invention;
fig. 4 is a schematic structural diagram of a pressure control device according to a second embodiment of the present invention.
Detailed Description
In order to solve the technical problems that in the prior art, the purity of nitrogen is reduced and the quality of a nitrogen finished product is influenced due to the fact that the upper tower pressure fluctuation of an air separation device is caused by the fact that the pipe diameter of a waste nitrogen pipeline is reduced, the invention provides a pressure control method and a pressure control device, and the pressure control method and the pressure control device are applied to an air separation system, wherein the air separation system comprises: a first pure nitrogen pipeline, a second pure nitrogen pipeline, a third pure nitrogen pipeline, a first waste nitrogen pipeline, a second waste nitrogen pipeline, a third waste nitrogen pipeline and a fourth waste nitrogen pipeline; the third pure nitrogen pipeline and the first waste nitrogen pipeline are connected with a nitrogen water tower, and the second waste nitrogen pipeline and the third waste nitrogen pipeline are connected with a molecular sieve; the method comprises the following steps: controlling the opening degree of a first valve on the first pure nitrogen pipeline to be 30-35%, and controlling the opening degree of a second valve on the second pure nitrogen pipeline to be 30-35%; when the molecular sieve is determined to be in a heating stage or a cold blowing stage, controlling a first opening of a third valve on a third pure nitrogen pipeline based on a preset upper tower pressure; the preset upper tower pressure is 36 KPa; and controlling a fourth valve on the first waste nitrogen pipeline to be closed, and controlling a sixth valve on the fourth waste nitrogen pipeline to be closed.
The technical solution of the present invention is further described in detail by the accompanying drawings and the specific embodiments.
Example one
The present embodiment provides a pressure control method, which is applied to an air separation system, and in order to better understand the technical solution herein, the overall structure of the air separation system is described first. Referring to fig. 1, the air separation system includes: the system comprises a cooling box 1, an air filter chamber 2, an air compressor 3, an air cooling tower 4, a nitrogen water tower 5, a refrigerator 6, a water pump 7, a supercharger 8, an expander 9, a liquid oxygen pump 10, a heater 11 and a molecular sieve.
Referring to fig. 2, an air separation column 20 and a plate heat exchanger 22 are installed in the cold box 1, the air separation column 20 comprises an upper column 21 and a lower column, a pure nitrogen pipeline and a waste nitrogen pipeline are separated from the upper column 21, and finished nitrogen is discharged from the pure nitrogen pipeline and is used for providing nitrogen for enterprises. The pure nitrogen line includes: a first pure nitrogen line 23, a second pure nitrogen line 24, a third pure nitrogen line 25 and a fourth pure nitrogen line 26, the waste nitrogen line comprising: a first dirty nitrogen line 27, a second dirty nitrogen line 28, a third dirty nitrogen line 29, and a fourth dirty nitrogen line 30.
The air filter chamber 2 is used for filtering dust in air, and then the air enters the air compressor 3 to be compressed, and the air compressor 3 compresses the air into air with the pressure of about 5 bar.
The air cooling tower 4 is used for cooling air, reducing moisture entering the molecular sieve and reducing heat entering the air separation tower. The cooling water from the refrigerator 6 is sprayed from the upper part of the air cooling tower 4, and the air enters from the lower part and flows out from the upper pipe.
The nitrogen water tower 5 is used for cooling water returned from the air cooling tower 4 or new production water is added just by spraying, normal-temperature polluted nitrogen gas coming out of the plate heat exchanger 22 enters from the lower part of the nitrogen water tower 5, water is sprayed from the upper part of the nitrogen water tower 5, and as the polluted nitrogen gas does not contain water, a part of water is taken away after passing through the nitrogen water tower, namely the water is partially evaporated, the water is evaporated to absorb heat, so that the temperature of the water sprayed into the nitrogen water tower 5 is reduced. Since the pressure in the air cooling tower 4 is higher than the pressure in the nitrogen water tower 5, the water after cooling the air automatically flows back into the nitrogen water tower 5 from the air cooling tower 4 to be cooled again, and at this time, a part of water needs to be supplemented.
The refrigerator 6 is a machine which consumes electric energy for refrigeration and is used for further cooling the water from the nitrogen water tower, and then the water is sent to the air cooling tower 4 through a water pump 7.
The molecular sieve comprises: the first molecular sieve 12 and the second molecular sieve 13, the first molecular sieve 12 and the second molecular sieve 13 are respectively connected with the heater 11, and spherical particles with main components of alumina, silicon oxide, sodium oxide and magnesium oxide are filled in the first molecular sieve 12 and the second molecular sieve 13, so that the water absorption is strong, moisture, carbon dioxide and the like in air can be adsorbed, and the ice formation in the cold box 1 can be prevented from blocking pipelines.
The first molecular sieve 12 and the second molecular sieve 13 lose their functions after absorbing water, and the first molecular sieve 12 and the second molecular sieve 13 need to be heated by heated dry (water molecule-free) polluted nitrogen to release water, and then the first molecular sieve 12 and the second molecular sieve 13 are blown off by normal-temperature dry polluted nitrogen to take away the released water and release the water to the atmosphere, and the whole process is called as activation regeneration of the molecular sieves. The first molecular sieve 12 and the second molecular sieve 13 are switched by valve control. It is noted that in addition to the heating and cold blowing steps, other stages are not required for the nitrogen purge.
When the first molecular sieve 12 and the second molecular sieve 13 are heated, the dirty nitrogen enters the first molecular sieve 12 and the second molecular sieve 13 through the heater 11, and when the first molecular sieve 12 and the second molecular sieve 13 are cold-blown, the dirty nitrogen directly enters the first molecular sieve 12 and the second molecular sieve 13 from a bypass.
Booster 8 compresses the clean air from either first molecular sieve 12 or second molecular sieve 13 into higher pressure air.
The plate heat exchanger 22 is used for exchanging heat of various gases, so that the gases entering the air separation column 20 are all low-temperature gases or liquids, and the gases entering the user side are all normal-temperature gases. This allows the refrigeration capacity in the air separation column 20 to be preserved without loss. The pressure and flow of various media passing through the heat exchanger are stabilized as much as possible so as to ensure normal heat exchange, normal gas-liquid conversion and the like.
The expander 9 is an energy conversion device which achieves the purpose of cooling air by expanding high-pressure air from a supercharger 8 into air of lower pressure of 5bar by using the principle that the expansion temperature of gas can be reduced, and sends the cooled air into an air separation column 20.
The liquid oxygen pump 10 pressurizes the liquid oxygen from the air separation column 20 to about 30bar, and the liquid oxygen is converted into normal temperature oxygen through heat exchange with hot air by the heat exchanger 22 and finally conveyed to a user.
Here, with continued reference to fig. 2, the first pure nitrogen line 23, the second pure nitrogen line 24 are connected to the nitrogen compressor train 31, the third pure nitrogen line 25 and the first waste nitrogen line 27 are connected to the nitrogen water tower 5, and the fourth pure nitrogen line 26 is used for discharging nitrogen gas.
Here, the waste nitrogen from the first waste nitrogen pipeline 27 is a normal temperature gas, enters the nitrogen water tower 5, is directly released into the atmosphere after being cooled by water supply under the action of moisture absorption, and is recycled, so that the purposes of energy conservation and consumption reduction are achieved. The second waste nitrogen pipeline 28 and the third waste nitrogen pipeline 29 are respectively connected with the first molecular sieve 12 and the second molecular sieve 13, and the first molecular sieve 12 and the second molecular sieve 13 are also connected with the heater 11; the fourth dirty nitrogen line 30 is used to bleed dirty nitrogen. The molecular sieve removes gases such as moisture, carbon dioxide and the like in the air by using an adsorption principle, prevents the moisture and the carbon dioxide in the air from entering the cold box 1, and avoids causing pipeline blockage. After the molecular sieve is saturated, the molecular sieve will lose its effectiveness and can no longer absorb moisture and carbon dioxide, and at this time, the molecular sieve needs to be regenerated and activated, and taking the second molecular sieve 13 as an example, when the second molecular sieve 13 is in a heating state or a cold blowing state, it indicates that the second molecular sieve 13 is in an activation and regeneration stage.
The first pure nitrogen pipeline 23 is provided with a first valve V11, the second pure nitrogen pipeline 24 is provided with a second valve V13, the third pure nitrogen pipeline 25 is provided with a third valve V14, and the fourth pure nitrogen pipeline 26 is provided with a fifth valve V12.
The fourth valve V21 is installed on the first waste nitrogen pipeline 27, the heating valve V23 is installed on the second waste nitrogen pipeline 28, the cold blowing valve V24 is installed on the third waste nitrogen pipeline 29, and the sixth valve V22 is installed on the fourth waste nitrogen pipeline 30.
Here, a flow meter FT11 is further installed on the header pipe of the first pure nitrogen line 23 and the fourth pure nitrogen line 26, and a flow meter FT12 is further installed on the header pipe of the second pure nitrogen line 24 and the third pure nitrogen line 25; a pressure gauge PT21 and a flow gauge FT21 are also arranged at the main pipe of the waste nitrogen pipeline; a pressure gauge PT11 is also mounted at the upper column.
Then, referring to fig. 3, the pressure control method includes:
s310, controlling the opening of a first valve on the first pure nitrogen pipeline to be 30-35%, and controlling the opening of a second valve on the second pure nitrogen pipeline to be 30-35%;
in order to ensure the nitrogen consumption of the downstream production line, whether the molecular sieve is in a heating stage or a cold blowing stage, the opening degree of a first valve on a first pure nitrogen pipeline is controlled to be 30-35%, and the opening degree of a second valve on a second pure nitrogen pipeline is controlled to be 30-35%; and the pure nitrogen output by the first pure nitrogen pipeline and the second pure nitrogen pipeline enters a nitrogen compressor unit, and is pressurized and then supplied to a downstream production line. Wherein the molecular sieve described herein may be any one of the first molecular sieve and the second molecular sieve.
Here, in order to ensure the working efficiency, the first molecular sieve and the second molecular sieve are alternately operated, and when the first molecular sieve is in an activated stage, the second molecular sieve is in a non-activated stage; when the first molecular sieve is in the inactive stage, the second molecular sieve is in the active stage.
In addition, in any stage, the opening degree of the fifth valve V12 is adjusted, so that the sum of the nitrogen flow rate of the first pure nitrogen pipeline and the nitrogen flow rate of the fourth pure nitrogen pipeline is stabilized at 50-55%, preferably 50%, of the total nitrogen flow rate.
S311, when the molecular sieve is determined to be in a heating stage or a cold blowing stage, controlling a first opening of a third valve on a third pure nitrogen pipeline based on preset upper tower pressure; and controlling a fourth valve on the first waste nitrogen pipeline to be closed, and controlling a sixth valve on the fourth waste nitrogen pipeline to be closed.
When the molecular sieve is determined to be in the heating stage or the cold blowing stage, the first waste nitrogen pipeline and the fourth waste nitrogen pipeline are both in a closed state and do not participate in the pressure regulation of the upper tower, and then the fourth valve on the first waste nitrogen pipeline is controlled to be closed, and the sixth valve on the fourth waste nitrogen pipeline is controlled to be closed.
Meanwhile, the control mode of the V14 switching the third valve is a pressure control mode, specifically, the first opening degree of the third valve on the third pure nitrogen pipeline is controlled based on the preset upper column pressure (the preset upper column pressure is 36KPa), so that the upper column pressure is always kept at 36 KPa. And when the molecular sieve is in a heating stage or a cold blowing stage, the valve opening corresponding to the flow control mode is 100%, the valve opening is the maximum value, the flow control mode is naturally invalid, and the pressure control mode is put into operation.
For example, in order to maintain the pressure of the dirty nitrogen line and ensure the regeneration and activation effects of the molecular sieve, more dirty nitrogen is extracted from the upper tower, so that the pressure in the upper tower is reduced, and at this time, the first opening of the third valve is controlled to be reduced based on the preset upper tower pressure, so that the amount of pure nitrogen flowing to the third pure nitrogen line is reduced, and thus the pressure in the upper tower is increased.
Here, as an alternative example, when the molecular sieve is in the heating stage, the method includes: and controlling the heating valve to be opened, and adjusting the opening degree of the heating valve on the second waste nitrogen pipeline to be about 80% in real time based on the waste nitrogen amount required by the molecular sieve. The amount of contaminated nitrogen required for the molecular sieve in the heating stage is approximately 50000Nm3/h。
When the molecular sieve is in the cold blowing stage, comprising: controlling the cold blow valve to be opened, and adjusting the opening degree of the cold blow valve on the third waste nitrogen pipeline to be about 90% in real time based on the waste nitrogen amount required by the molecular sieve, wherein the waste nitrogen amount required by the molecular sieve in the cold blow stage is about 70000Nm3/h。
As an alternative example, when the molecular sieve is in the heating stage or the cold blowing stage, if the heating valve or the cold blowing valve fails to cause interruption of heating or cold blowing on the molecular sieve, the upper tower pressure may be rapidly increased, and at this time, if it is not enough to adjust the upper tower pressure by using the third valve and it is necessary to adjust the upper tower pressure by using the fourth valve installed on the first dirty nitrogen pipeline to release the dirty nitrogen, when the molecular sieve is in the heating stage or the cold blowing stage, the method further includes:
and acquiring the actual pressure in the upper tower, and controlling the fourth valve to be opened if the actual pressure is higher than a preset maximum limit value. The present embodiment sets the maximum limit value to 37 KPa.
As an alternative example, when it is determined that the molecular sieve is in the inactive phase, i.e. the molecular sieve does not require the flow of the waste nitrogen, the control mode of the third valve V14 is switched to the flow control, specifically: controlling a heating valve on a second waste nitrogen pipeline to be closed, controlling a cold blowing valve on a third waste nitrogen pipeline to be closed, controlling the opening degree of a fourth valve on the first waste nitrogen pipeline to be 40-50%, and adjusting the opening degree of a sixth valve based on the preset upper tower pressure, wherein the preset upper tower pressure is 36 kPa;
and controlling a second opening degree of a third valve V14 on a third pure nitrogen pipeline based on the reserved nitrogen flow in the cold box, wherein the reserved nitrogen flow is 50-55% of the total nitrogen, and preferably 50%.
It should be noted that the pressure, flow rate and valve opening degree related to the present embodiment may be different in different air separation systems or different production loads.
Based on the same inventive concept, the invention also provides a pressure control device, which is detailed in embodiment two.
Example two
The present embodiment provides a pressure control apparatus, which is applied to the air separation system as mentioned in the first embodiment, as shown in fig. 4, the apparatus includes: a first control unit 41, a second control unit 42, a third control unit 43, a fourth control unit 44, a fifth control unit 45, a sixth control unit 46, a seventh control unit 47; wherein,
in order to ensure the nitrogen consumption of the downstream production line, no matter whether the molecular sieve is in the heating stage or the cold blowing stage, the first control unit 41 controls the opening of the first valve on the first pure nitrogen pipeline to be 30-35%, and the second control unit 42 controls the opening of the second valve on the second pure nitrogen pipeline to be 30-35%; and the pure nitrogen output by the first pure nitrogen pipeline and the second pure nitrogen pipeline enters a nitrogen compressor unit, and is pressurized and then supplied to a downstream production line. Wherein the molecular sieve described herein may be any one of the first molecular sieve and the second molecular sieve.
Here, in order to ensure the working efficiency, the first molecular sieve and the second molecular sieve are alternately operated, and when the first molecular sieve is in an activated stage, the second molecular sieve is in a non-activated stage; when the first molecular sieve is in the inactive stage, the second molecular sieve is in the active stage.
In addition, in any stage, the sum of the nitrogen flow rates of the first pure nitrogen pipeline and the fourth pure nitrogen pipeline is stabilized to 50-55%, preferably 50%, of the total nitrogen flow rate by adjusting the opening degree of the fifth valve V12.
When the molecular sieve is determined to be in the heating stage or the cold blowing stage, the fourth control unit 44 is configured to control the fourth valve on the first sewage nitrogen pipeline to be closed; a fifth control unit 45 is arranged to control the sixth valve on the fourth dirty nitrogen line to close. So that the first waste nitrogen pipeline and the fourth waste nitrogen pipeline are both in a closed state and do not participate in the pressure regulation of the upper tower.
Simultaneously, the control mode of the V14 of the third valve is switched to pressure control, and the third control unit 43 controls the first opening of the third valve on the third pure nitrogen pipeline based on the preset upper tower pressure; the preset upper tower pressure is 36 KPa.
And when the molecular sieve is in a heating stage or a cold blowing stage, the valve opening corresponding to the flow control mode is 100%, the valve opening is the maximum value, the flow control mode is naturally invalid, and the pressure control mode is put into operation.
For example, in order to maintain the pressure of the dirty nitrogen line and ensure the regeneration and activation effects of the molecular sieve, more dirty nitrogen is extracted from the upper tower, so that the pressure in the upper tower is reduced, and at this time, the first opening of the third valve is controlled to be reduced based on the preset upper tower pressure, so that the amount of pure nitrogen flowing to the third pure nitrogen line is reduced, and thus the pressure in the upper tower is increased.
When the molecular sieve is in the heating phase, the sixth control unit 46 is configured to: the heating valve is controlled to be opened, the opening degree of the heating valve on the second waste nitrogen pipeline is adjusted in real time based on the waste nitrogen amount required by the molecular sieve, the opening degree of the heating valve on the second waste nitrogen pipeline is controlled to be about 80%, and the waste nitrogen amount required by the molecular sieve in the heating stage is about 50000Nm3/h。
When the molecular sieve is in the cold blowing stage, the seventh control unit 47 is configured to: controlling a cold blow valve to be opened, adjusting the opening degree of the cold blow valve on a third waste nitrogen pipeline in real time based on the waste nitrogen amount required by the molecular sieve, controlling the opening degree of the cold blow valve on the third waste nitrogen pipeline to be about 90%, and controlling the waste nitrogen amount required by the molecular sieve in a cold blow stage to be about 70000Nm3/h。
As an alternative example, when the molecular sieve is in the heating stage or the cold blowing stage, if the heating valve or the cold blowing valve fails to stop heating or cold blowing the molecular sieve, the upper tower pressure may be rapidly increased, and if the adjustment of the upper tower pressure by using only the third valve is not enough and the adjustment of the upper tower pressure by using the fourth valve installed on the first contaminated nitrogen line is needed to simultaneously adjust and release the contaminated nitrogen, the fourth control unit 44 is further configured to:
and acquiring the actual pressure in the upper tower, and controlling the fourth valve to be opened if the actual pressure is higher than a preset maximum limit value. The present embodiment sets the maximum limit value to 37 KPa.
As an alternative example, when it is determined that the molecular sieve is in the inactive phase, i.e. the molecular sieve does not require the flow of the waste nitrogen, the control mode of the third valve V14 is switched to the flow control, specifically: the sixth control unit 46 controls the heating valve on the second waste nitrogen pipeline to be closed, the seventh control unit 47 controls the cold blow valve on the third waste nitrogen pipeline to be closed, the fourth control unit 44 controls the opening degree of the fourth valve on the first waste nitrogen pipeline to be 40-50%, the fifth control unit 45 is used for adjusting the opening degree of the sixth valve based on the preset upper tower pressure, and the preset upper tower pressure is 36 kPa; the third control unit 43 is further configured to control a second opening degree of a third valve V14 on the third pure nitrogen line based on a reserved nitrogen flow rate in the cold box, where the reserved nitrogen flow rate is 50-55%, preferably 50%, of the total nitrogen amount.
It should be noted that the pressure, flow rate and valve opening degree related to the present embodiment may be different in different air separation systems or different production loads.
The embodiment of the invention can bring the following beneficial effects:
at molecular sieve heating or cold blow stage, if the dirty nitrogen volume that needs increases, when extracting dirty nitrogen from last tower, then through the first aperture of the third valve on the control third pure nitrogen pipeline, suitably reduce the pure nitrogen volume that the third pure nitrogen pipeline flows out, and the fourth valve on the control first dirty nitrogen pipeline is closed, the sixth valve on the control fourth dirty nitrogen pipeline is closed, reduce dirty nitrogen outflow, make the pressure of going up the tower remain at 36KPa all the time, just so can avoid the pressure of going up the tower to produce undulantly, and then avoid influencing the purity of nitrogen gas product, ensured nitrogen gas quality. Therefore, the requirements of the molecular sieve on the flow of the waste nitrogen are met, the influence of the pressure fluctuation of the upper tower on the rectification working condition is avoided, and the quality of the nitrogen is ensured.
In the non-activation stage of the molecular sieve, the control of the pressure of the upper tower is automatically switched to a fourth valve and a sixth valve on a waste nitrogen pipeline, the fourth valve is in a fixed opening degree and meets the requirement of cooling the nitrogen water tower, the pressure of the upper tower is dynamically regulated by the sixth valve, and the third valve is switched to a flow control mode. And the third valve adopts a pressure control mode in the activation stage of the molecular sieve, adopts a flow control mode in the non-activation stage, and circularly switches the control modes in the activation stage and the non-activation stage of the molecular sieve. The pressure of the upper tower can be stabilized in the whole molecular sieve period.
And when the heating valve or the cold blowing valve corresponding to the molecular sieve breaks down, the third valve and the fourth valve can be simultaneously utilized to adjust the pressure of the upper tower, so that the pressure of the upper tower is ensured to be stable, the production can be continuously kept, and the production efficiency is ensured.
The above description is only exemplary of the present invention and should not be taken as limiting the scope of the present invention, and any modifications, equivalents, improvements, etc. that are within the spirit and principle of the present invention should be included in the present invention.
Claims (10)
1. A pressure control method applied to an air separation system, the air separation system comprising: a first pure nitrogen pipeline, a second pure nitrogen pipeline, a third pure nitrogen pipeline, a first waste nitrogen pipeline, a second waste nitrogen pipeline, a third waste nitrogen pipeline and a fourth waste nitrogen pipeline; the third pure nitrogen pipeline and the first waste nitrogen pipeline are connected with a nitrogen water tower, and the second waste nitrogen pipeline and the third waste nitrogen pipeline are connected with a molecular sieve; the method comprises the following steps:
controlling the opening degree of a first valve on the first pure nitrogen pipeline to be 30-35%, and controlling the opening degree of a second valve on the second pure nitrogen pipeline to be 30-35%;
when the molecular sieve is determined to be in a heating stage or a cold blowing stage, controlling a first opening of a third valve on a third pure nitrogen pipeline based on a preset upper tower pressure; the preset upper tower pressure is 36 KPa;
and controlling a fourth valve on the first waste nitrogen pipeline to be closed, and controlling a sixth valve on the fourth waste nitrogen pipeline to be closed.
2. The method of claim 1, wherein the method further comprises:
when the molecular sieve is determined to be in the non-activation stage, controlling the opening degree of the fourth valve to be 40-50%, and adjusting the opening degree of the sixth valve based on the preset upper tower pressure;
controlling a second opening degree of the third valve based on nitrogen flow reserved in the cold box, wherein the reserved nitrogen flow is 50-55% of the total nitrogen amount;
and controlling a heating valve on the second waste nitrogen pipeline to be closed, and controlling a cold blowing valve on the third waste nitrogen pipeline to be closed.
3. The method of claim 1, wherein when the molecular sieve is in the heating stage or the cold blowing stage, further comprising:
and acquiring the actual pressure in the upper tower, and controlling the fourth valve to be opened if the actual pressure is higher than a preset maximum limit value.
4. The method of claim 1, wherein when the molecular sieve is in the heating stage, comprising: adjusting an opening of a heating valve on the second dirty nitrogen line based on a required amount of dirty nitrogen for the molecular sieve.
5. The method of claim 1, wherein when the molecular sieve is in the cold blowing stage, comprising: and adjusting the opening degree of a cold blow valve on the third waste nitrogen pipeline based on the required waste nitrogen amount of the molecular sieve.
6. A pressure control apparatus, characterized by being applied to an air separation system, the air separation system comprising: a first pure nitrogen pipeline, a second pure nitrogen pipeline, a third pure nitrogen pipeline, a first waste nitrogen pipeline, a second waste nitrogen pipeline, a third waste nitrogen pipeline and a fourth waste nitrogen pipeline; the third pure nitrogen pipeline and the first waste nitrogen pipeline are connected with a nitrogen water tower, and the second waste nitrogen pipeline and the third waste nitrogen pipeline are connected with a molecular sieve; the device comprises:
the first control unit is used for controlling the opening degree of a first valve on the first pure nitrogen pipeline to be 30-35%;
the second control unit is used for controlling the opening of a second valve on the second pure nitrogen pipeline to be 30-35%;
the third control unit is used for controlling the first opening of a third valve on the third pure nitrogen pipeline based on preset upper tower pressure when the molecular sieve is determined to be in the heating stage or the cold blowing stage; the preset upper tower pressure is 36 KPa;
the fourth control unit is used for controlling a fourth valve on the first sewage nitrogen pipeline to be closed;
and the fifth control unit is used for controlling a sixth valve on the fourth waste nitrogen pipeline to be closed.
7. The apparatus of claim 6, wherein the apparatus further comprises: a sixth control unit and a seventh control unit;
when it is determined that the molecular sieve is in the inactive stage, the third control unit is further to: controlling a second opening degree of the third valve based on nitrogen flow reserved in the cold box, wherein the reserved nitrogen flow is 50-55% of the total nitrogen amount;
the fourth control unit is further configured to: controlling the opening of the fourth valve to be 40-50%;
the fifth control unit is further configured to: adjusting the opening degree of the sixth valve based on the preset upper tower pressure;
the sixth control unit is configured to: controlling a heating valve on the second waste nitrogen pipeline to close;
the seventh control unit is configured to: and controlling a cold blow valve on the third waste nitrogen pipeline to be closed.
8. The apparatus of claim 6, wherein the fourth control unit is further to: and when the molecular sieve is in a heating stage or a cold blowing stage, acquiring the actual pressure in the upper tower, and if the actual pressure is higher than a preset maximum limit value, controlling the fourth valve to be opened.
9. The apparatus of claim 7, wherein the sixth control unit is further configured to: adjusting an opening of a heating valve on the second dirty nitrogen line based on a desired amount of dirty nitrogen for the molecular sieve when the molecular sieve is in a heating stage.
10. The apparatus of claim 7, wherein the seventh control unit is further to: and when the molecular sieve is in a cold blowing stage, adjusting the opening degree of a cold blowing valve on the third dirty nitrogen pipeline based on the dirty nitrogen amount required by the molecular sieve.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910862915.6A CN110608583B (en) | 2019-09-12 | 2019-09-12 | Pressure control method and device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910862915.6A CN110608583B (en) | 2019-09-12 | 2019-09-12 | Pressure control method and device |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN110608583A CN110608583A (en) | 2019-12-24 |
| CN110608583B true CN110608583B (en) | 2021-07-23 |
Family
ID=68892641
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201910862915.6A Active CN110608583B (en) | 2019-09-12 | 2019-09-12 | Pressure control method and device |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN110608583B (en) |
Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0949471A1 (en) * | 1998-04-08 | 1999-10-13 | Linde Aktiengesellschaft | Cryogenic air separation plant with two different operation modes |
| US5979182A (en) * | 1997-03-13 | 1999-11-09 | Kabushiki Kaisha Kobe Seiko Sho | Method of and apparatus for air separation |
| JP3237892B2 (en) * | 1992-03-18 | 2001-12-10 | 株式会社日立製作所 | Pressurized air separation device |
| CN102380361A (en) * | 2011-08-31 | 2012-03-21 | 莱芜钢铁股份有限公司 | Process utilizing product nitrogen gas to involve regeneration of molecular sieve absorbers |
| CN203375800U (en) * | 2013-06-24 | 2014-01-01 | 湖南宜化化工有限责任公司 | Deep cooling air separation oxygen generation system by adoption of synthesis ammonia process |
| CN105928319A (en) * | 2016-05-13 | 2016-09-07 | 深圳市海格金谷化工科技有限公司 | Cryogenic nitrogen generation control system |
| CN108072234A (en) * | 2016-11-15 | 2018-05-25 | 北大方正集团有限公司 | The control method of air-separating plant |
| CN110108090A (en) * | 2019-04-26 | 2019-08-09 | 北京科技大学 | A method of reducing air separation unit upper tower pressure and system energy consumption |
-
2019
- 2019-09-12 CN CN201910862915.6A patent/CN110608583B/en active Active
Patent Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP3237892B2 (en) * | 1992-03-18 | 2001-12-10 | 株式会社日立製作所 | Pressurized air separation device |
| US5979182A (en) * | 1997-03-13 | 1999-11-09 | Kabushiki Kaisha Kobe Seiko Sho | Method of and apparatus for air separation |
| EP0949471A1 (en) * | 1998-04-08 | 1999-10-13 | Linde Aktiengesellschaft | Cryogenic air separation plant with two different operation modes |
| CN102380361A (en) * | 2011-08-31 | 2012-03-21 | 莱芜钢铁股份有限公司 | Process utilizing product nitrogen gas to involve regeneration of molecular sieve absorbers |
| CN203375800U (en) * | 2013-06-24 | 2014-01-01 | 湖南宜化化工有限责任公司 | Deep cooling air separation oxygen generation system by adoption of synthesis ammonia process |
| CN105928319A (en) * | 2016-05-13 | 2016-09-07 | 深圳市海格金谷化工科技有限公司 | Cryogenic nitrogen generation control system |
| CN108072234A (en) * | 2016-11-15 | 2018-05-25 | 北大方正集团有限公司 | The control method of air-separating plant |
| CN110108090A (en) * | 2019-04-26 | 2019-08-09 | 北京科技大学 | A method of reducing air separation unit upper tower pressure and system energy consumption |
Non-Patent Citations (2)
| Title |
|---|
| "三万五"制氧机空分塔压力稳定的控制方案;张瑜峰; 徐文革;《华夏星火》;20011010;第52-53页 * |
| 分子筛自动切换程序的优化控制;李秀英; 梁日钧;《包钢科技》;20090415;第56-58页 * |
Also Published As
| Publication number | Publication date |
|---|---|
| CN110608583A (en) | 2019-12-24 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN107940801B (en) | A kind of space division system recycling compressed air waste-heat | |
| CN207379163U (en) | Supercharging stream backed expansion nitrogen making machine after oxygen-enriched | |
| CN201173660Y (en) | Middle and small sized multi- behavior energy-saving -type air separation equipment | |
| CN110787587A (en) | Air separation purification pressure equalizing system and control method | |
| JP7460973B2 (en) | air separation equipment | |
| CN102380361B (en) | Process utilizing product nitrogen gas to involve regeneration of molecular sieve absorbers | |
| CN110608583B (en) | Pressure control method and device | |
| CN208332861U (en) | A kind of space division system | |
| CN211234024U (en) | Air separation equipment | |
| CN202057113U (en) | Heat pump unit and comprehensive energy-saving system | |
| CN203928596U (en) | The recycling device of the dirty nitrogen of a kind of air separation | |
| CN110986620A (en) | Air separation equipment | |
| CN202238066U (en) | Device for product nitrogen gas to participate in molecular sieve adsorber regeneration | |
| CN218973023U (en) | Air separation system pre-cooled by regenerated gas heat exchanger | |
| JPH0584418A (en) | Pretreatment of air separator and equipment therefor | |
| CN111238167A (en) | Energy-saving heating device and method for air separation device | |
| CN215559004U (en) | Medical modularized combined oxygen generator | |
| RU2696437C1 (en) | Method of waste gas regeneration treatment | |
| CN115709971B (en) | Hydrogen purification system and control method | |
| CN218545021U (en) | Purification system and air separation device | |
| CN109737690A (en) | Compression large scale liquid space division device and its application method in a kind of | |
| CN111981760B (en) | Heating and unfreezing method of low-temperature air separation device | |
| CN218290822U (en) | Natural gas dehydration system utilizing system pressure regeneration | |
| CN109988660A (en) | Natural gas purification system and natural gas purification method | |
| CN111486663B (en) | Nitrogen making machine suitable for electronic gas factory |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |