CN117339385A - Feed gas treatment system and feed gas treatment method - Google Patents
Feed gas treatment system and feed gas treatment method Download PDFInfo
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- CN117339385A CN117339385A CN202311643129.XA CN202311643129A CN117339385A CN 117339385 A CN117339385 A CN 117339385A CN 202311643129 A CN202311643129 A CN 202311643129A CN 117339385 A CN117339385 A CN 117339385A
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- 238000000034 method Methods 0.000 title claims abstract description 11
- 239000007789 gas Substances 0.000 claims abstract description 219
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims abstract description 196
- 239000001301 oxygen Substances 0.000 claims abstract description 196
- 229910052760 oxygen Inorganic materials 0.000 claims abstract description 196
- 238000007254 oxidation reaction Methods 0.000 claims abstract description 81
- 230000003197 catalytic effect Effects 0.000 claims abstract description 73
- 239000012535 impurity Substances 0.000 claims abstract description 61
- 239000002994 raw material Substances 0.000 claims abstract description 56
- 230000003647 oxidation Effects 0.000 claims abstract description 51
- 238000012544 monitoring process Methods 0.000 claims abstract description 30
- 238000006213 oxygenation reaction Methods 0.000 claims abstract description 27
- 239000011261 inert gas Substances 0.000 claims abstract description 18
- 230000008859 change Effects 0.000 claims abstract description 9
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims description 22
- 238000001514 detection method Methods 0.000 claims description 12
- 229910052757 nitrogen Inorganic materials 0.000 claims description 11
- 238000012545 processing Methods 0.000 claims description 11
- 238000006243 chemical reaction Methods 0.000 claims description 8
- 230000009467 reduction Effects 0.000 claims description 6
- 230000008569 process Effects 0.000 claims description 5
- 238000003672 processing method Methods 0.000 claims description 4
- MYMOFIZGZYHOMD-UHFFFAOYSA-N Dioxygen Chemical compound O=O MYMOFIZGZYHOMD-UHFFFAOYSA-N 0.000 claims description 2
- 229910001882 dioxygen Inorganic materials 0.000 claims description 2
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 description 20
- 238000001179 sorption measurement Methods 0.000 description 18
- 238000000746 purification Methods 0.000 description 15
- 238000006555 catalytic reaction Methods 0.000 description 10
- 230000001105 regulatory effect Effects 0.000 description 8
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 description 7
- 229910002091 carbon monoxide Inorganic materials 0.000 description 7
- 239000001257 hydrogen Substances 0.000 description 7
- 229910052739 hydrogen Inorganic materials 0.000 description 7
- 238000002955 isolation Methods 0.000 description 6
- 150000002431 hydrogen Chemical class 0.000 description 5
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 description 4
- 229920006395 saturated elastomer Polymers 0.000 description 4
- 230000001276 controlling effect Effects 0.000 description 3
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 2
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 2
- 206010021143 Hypoxia Diseases 0.000 description 2
- 238000004364 calculation method Methods 0.000 description 2
- 229910002092 carbon dioxide Inorganic materials 0.000 description 2
- 239000001569 carbon dioxide Substances 0.000 description 2
- 239000003054 catalyst Substances 0.000 description 2
- 239000007795 chemical reaction product Substances 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 238000001914 filtration Methods 0.000 description 2
- 229910052751 metal Inorganic materials 0.000 description 2
- 239000002184 metal Substances 0.000 description 2
- 229910044991 metal oxide Inorganic materials 0.000 description 2
- 150000004706 metal oxides Chemical class 0.000 description 2
- 230000008929 regeneration Effects 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 2
- 230000002159 abnormal effect Effects 0.000 description 1
- 230000009471 action Effects 0.000 description 1
- 229910052786 argon Inorganic materials 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 239000012159 carrier gas Substances 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 238000011143 downstream manufacturing Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 239000001307 helium Substances 0.000 description 1
- 229910052734 helium Inorganic materials 0.000 description 1
- SWQJXJOGLNCZEY-UHFFFAOYSA-N helium atom Chemical compound [He] SWQJXJOGLNCZEY-UHFFFAOYSA-N 0.000 description 1
- 229910052743 krypton Inorganic materials 0.000 description 1
- DNNSSWSSYDEUBZ-UHFFFAOYSA-N krypton atom Chemical compound [Kr] DNNSSWSSYDEUBZ-UHFFFAOYSA-N 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 229910052754 neon Inorganic materials 0.000 description 1
- GKAOGPIIYCISHV-UHFFFAOYSA-N neon atom Chemical compound [Ne] GKAOGPIIYCISHV-UHFFFAOYSA-N 0.000 description 1
- 230000036284 oxygen consumption Effects 0.000 description 1
- 230000002035 prolonged effect Effects 0.000 description 1
- 238000011069 regeneration method Methods 0.000 description 1
- 239000004065 semiconductor Substances 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
- 230000001225 therapeutic effect Effects 0.000 description 1
- 229910052724 xenon Inorganic materials 0.000 description 1
- FHNFHKCVQCLJFQ-UHFFFAOYSA-N xenon atom Chemical compound [Xe] FHNFHKCVQCLJFQ-UHFFFAOYSA-N 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
- B01D53/34—Chemical or biological purification of waste gases
- B01D53/74—General processes for purification of waste gases; Apparatus or devices specially adapted therefor
- B01D53/86—Catalytic processes
- B01D53/8696—Controlling the catalytic process
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
- B01D53/34—Chemical or biological purification of waste gases
- B01D53/74—General processes for purification of waste gases; Apparatus or devices specially adapted therefor
- B01D53/86—Catalytic processes
- B01D53/90—Injecting reactants
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
- C01B23/00—Noble gases; Compounds thereof
- C01B23/001—Purification or separation processes of noble gases
- C01B23/0015—Chemical processing only
- C01B23/0021—Chemical processing only by oxidation
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2251/00—Reactants
- B01D2251/10—Oxidants
- B01D2251/102—Oxygen
Abstract
The invention discloses a feed gas treatment system and a feed gas treatment method, wherein the treatment system comprises: an air inlet unit provided with an air inlet amount monitoring module for monitoring the volume flow of the raw material gas which is fed into the catalytic oxidation unit, wherein the raw material gas is inert gas containing reducing gas impurities capable of reacting with oxygen; the oxygenation unit is provided with an air inflow control module for monitoring and adjusting the volume flow of oxygen introduced into the catalytic oxidation unit; a catalytic oxidation unit, wherein the reducing gas impurities and oxygen in the raw material gas undergo oxidation reaction in the catalytic oxidation unit to obtain purified gas; the control unit is connected with the air inflow monitoring module and the air inflow control module; the control unit controls the air inflow control module to adjust the volume flow of the oxygen according to the concentration of the reducing gas impurities in the raw material gas. The control unit controls the air inflow control module to adjust the volume flow of the oxygen which is introduced into the catalytic oxidation unit once at intervals of T according to the change of the oxygen concentration of the purified gas.
Description
Technical Field
The disclosure relates to the technical field of gas purification, in particular to a feed gas treatment system and a feed gas treatment method.
Background
The inert gas with high purity is electron and medicalRaw materials essential for the therapeutic industry and the like. Inert gas feed gases, e.g. N 2 The raw material gas contains reducing gas impurities such as methane, carbon monoxide, hydrogen and the like, and can be purified to obtain high-purity inert gas meeting the standard. The catalytic oxidation reaction of the impurities in the raw material gas is carried out in a high-temperature (300 ℃) catalytic unit, the impurities in the raw material gas react with oxygen to generate water and carbon dioxide, and the catalytic reaction of the impurities is as follows:
CH 4 +2O 2 →2H 2 O+CO 2
2CO+O 2 →2CO 2
2H 2 +O 2 →2H 2 O
the gas after the catalytic reaction of the high-temperature catalytic unit is continuously led into a normal-temperature adsorption unit at the rear end, and purified N is obtained after the water, the carbon dioxide and the oxygen in the gas are adsorbed by the adsorption unit 2 . The adsorption units are at least two, when one adsorption unit is saturated, the adsorption unit is switched to the other adsorption unit to continue adsorption, the adsorption unit with saturated adsorption starts a regeneration program to regenerate, and after regeneration is finished, the next switching is waited, and the cycle is performed so as to achieve the purpose of uninterrupted air supply.
Oxygen is needed in the high-temperature catalytic reaction, although oxygen is contained in the raw material gas, the fluctuation of the oxygen content is large, and the oxygen content in the raw material gas is insufficient to reoxidize the metal simple substance in a reduced state in the high-temperature catalytic unit into metal oxide with catalytic activity, so that the metal oxide catalyst in the high-temperature catalytic unit can be continuously reduced into the metal simple substance by the reduced impurities in the reaction process, and finally the catalytic activity is completely lost, so that methane, hydrogen and carbon monoxide impurities in the gas cannot be removed, and the downstream process is influenced.
Therefore, additional oxygen is required in the actual high temperature catalytic step to prevent this. In the inert gas purification system, oxygen is added into a high-temperature catalytic reaction unit through a pressure regulating valve and a restrictor, wherein the air inflow of the oxygen is controlled by controlling the pressure of the air inlet end of the restrictor, and then the air inflow is displayed through a float air inflow meter. Supplying oxygen in this way has the following two drawbacks:
1. the pressure regulating valve and the flow restrictor can only be controlled manually, and automatic control cannot be realized. When the air inflow of the raw material gas is increased, the methane content is increased, if the air inflow for supplying oxygen is unchanged at the moment, the high-temperature catalytic reaction of methane and oxygen is insufficient, impurities are not removed cleanly, the purity requirement cannot be met, and the rear end product can be seriously scrapped;
when the air inflow of the raw material gas is reduced, the actual oxygen consumption of the high-temperature catalytic unit is also reduced, and if the air inflow of the supplied oxygen is unchanged at the moment, the redundant oxygen enters the adsorption unit, so that the adsorption unit is saturated quickly, and the cycle period of the adsorption unit is shortened. The cycle time of the adsorption unit can be prolonged by increasing the volume of the adsorption unit, but the cost is increased. And after the adsorption unit is saturated due to high-concentration oxygen, oxygen impurities can enter a rear-end process pipeline to influence the purity of inert gas, and the rear-end product can be seriously scrapped.
2. The oxygen intake amount is displayed by the float intake air amount meter, and is greatly influenced by the pressure of oxygen. Because the calibration pressure of the float air inlet meter is a fixed value, when the actual oxygen pressure fluctuation is large, the air inlet amount is inaccurate, the actual air inlet amount is larger or smaller, the oxygen adding amount is inaccurate, and the oxygen or methane impurity is easy to exceed the standard.
Disclosure of Invention
Based on this, it is an object of the present disclosure to precisely control the amount of oxygen fed to a high temperature catalytic unit during the purification of an inert gas feed gas.
To achieve the above object, the present disclosure provides a feed gas processing system including:
the air inlet unit is provided with an air inflow monitoring module which is used for monitoring the volume flow of raw gas which is introduced into the catalytic oxidation unit, wherein the raw gas is inert gas containing reducing gas impurities capable of reacting with oxygen;
the oxygen adding unit is provided with an air inflow control module which is used for monitoring and adjusting the volume flow of oxygen introduced into the catalytic oxidation unit;
a catalytic oxidation unit, wherein the reducing gas impurities and the oxygen in the raw material gas undergo oxidation reaction in the catalytic oxidation unit to obtain purified gas;
the control unit is connected with the air inflow monitoring module and the air inflow control module and used for controlling the air inflow control module to adjust the volume flow of the oxygen according to the concentration of the reducing gas impurities in the raw gas;
the control unit also controls the air inflow control module to adjust the volume flow A of the oxygen which is introduced into the catalytic oxidation unit once at intervals of T according to the change of the oxygen concentration of the purified gas:
when residual oxygen is detected in the purified gas after a time interval T, the volume flow a is adjusted to: the volume flow of oxygen in the purified gas after the time interval T is subtracted from the volume flow of oxygen which is introduced into the catalytic oxidation unit before the time interval T;
when no oxygen is detected in the purified gas after a time interval T, the volume flow a is adjusted to: the volume flow of oxygen to the catalytic oxidation unit before the time interval T is added to the reduced volume flow of oxygen of the purified gas after the time interval T.
Preferably, when no oxygen is detected in the purified gas after time interval T and the oxygen volumetric flow is not reduced when adjusted before time interval T, the volumetric flow a is adjusted to: the volume flow of oxygen introduced into the catalytic oxidation unit before the time interval T is increased by the corresponding volume flow reduction when the volume flow of the most recently adjusted oxygen is reduced.
Preferably, the feed gas comprises at least two of the reducing gas impurities.
Preferably, the control unit calculates the volumetric flow rate of oxygen in the following manner:
calculating the oxygen volume ratio required by the complete oxidation reaction of each reducing gas impurity according to the volume ratio of each reducing gas impurity in the raw material gas,
and multiplying the sum of the oxygen volume ratios corresponding to the complete oxidation reaction of the reducing gas impurities by the volume flow of the raw material gas.
Preferably, the feed gas comprises high purity nitrogen or ultra high purity nitrogen in CB/T8979.
Preferably, the device further comprises a detection unit, wherein the detection unit is connected with the control unit and is at least used for detecting the oxygen concentration of the raw material gas before the catalytic oxidation reaction and the oxygen concentration of the purified gas obtained after the catalytic oxidation reaction.
More preferably, the control unit controls the intake air amount control module to adjust the volume flow of oxygen flowing into the catalytic oxidation unit once every time interval T according to the change of the oxygen concentration of the purified gas every time interval T.
More preferably, the volume flow of oxygen is:
and adding the volume flow of the oxygen calculated by the control unit with a compensation coefficient, wherein the value of the compensation coefficient is the volume flow corresponding to 0-0.2 ppm of oxygen.
To achieve the above object, the present disclosure also provides a feed gas processing method performed in the foregoing feed gas processing system, including the steps of:
s1, feeding back the monitored volumetric flow a of the raw gas to a control unit by an air inflow monitoring module in an air inflow unit;
s2, the control unit calculates the volume flow A of oxygen required by the reaction of the reducing gas impurities in the volume flow a according to the concentration of the reducing gas impurities in the raw material gas;
s3, the control unit controls an air inflow control module in the oxygenation unit to adjust the volume flow of oxygen to the volume flow A.
Preferably, the control unit calculates the volumetric flow a as follows:
and calculating the oxygen volume ratio required by the complete oxidation reaction of each reducing gas impurity according to the volume ratio of each reducing gas impurity in the raw material gas, and multiplying the sum of the oxygen volume ratios corresponding to the complete oxidation reaction of each reducing gas impurity by the volume flow of the raw material gas.
More preferably, the step of adjusting said volume flow a once per time interval T is also comprised:
the detection unit detects the oxygen concentration of the purified gas obtained after the catalytic oxidation reaction at intervals of T and feeds back the result to the control unit,
the control unit compares the oxygen concentration of the purified gas before and after the time interval T,
when residual oxygen is detected in the purified gas after a time interval T, the volume flow a is adjusted to: the volume flow of oxygen in the purified gas after the time interval T is subtracted from the volume flow of oxygen which is introduced into the catalytic oxidation unit before the time interval T;
when no oxygen is detected in the purified gas after a time interval T, the volume flow a is adjusted to: the oxygen volume flow which is introduced into the catalytic oxidation unit before the time interval T is added with the oxygen volume flow which is reduced by the purified gas after the time interval T;
when no oxygen is detected in the purified gas after time interval T and the oxygen volumetric flow is not reduced when adjusted before time interval T, then the volumetric flow a is adjusted to: the volume flow of oxygen introduced into the catalytic oxidation unit before the time interval T is increased by the corresponding volume flow reduction when the volume flow of the most recently adjusted oxygen is reduced.
More preferably, the method further comprises the step of compensating the volumetric flow of oxygen:
the volume flow A is as follows: and the volume flow of the oxygen calculated by the control unit is added with a compensation coefficient, wherein the value of the compensation coefficient is the volume flow corresponding to 0-0.2 ppm of oxygen.
The technical scheme claimed by the disclosure has the following beneficial effects:
1) The linkage of the oxygenation unit and the raw material gas inlet unit is realized, the volume flow of oxygen required by catalytic oxidation can be automatically regulated according to the volume flow of raw material gas and the concentration of the reducing gas impurities therein, the oxygenation amount is accurately controlled, excessive or insufficient oxygenation is avoided, the sufficient reaction of the reducing gas impurities and the oxygen is ensured, and the running stability of a purification system is ensured.
2) The detection unit detects the oxygen concentration of the raw material gas before and after catalytic oxidation, calculates and controls the actually required oxygen adding amount according to the change of the oxygen concentration in the purified gas obtained after the catalytic oxidation, and further realizes the accurate control of the oxygen amount.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present disclosure, the drawings required for the description of the embodiments will be briefly introduced below, and it is obvious that the drawings in the following description are only embodiments of the present disclosure, and other drawings may be obtained according to the provided drawings without inventive effort for a person skilled in the art.
FIG. 1 is a schematic diagram of an inert gas purification apparatus including a feed gas treatment system.
Fig. 2 is a block diagram of a feed gas processing system.
Reference numerals:
1-a mass flowmeter; 2-a manual isolation valve; 3-a first intake pressure sensor; 4-a first manual valve; 5-mass flow controller; 6-a second manual valve; 7-a filter; 8-a pressure regulating valve with a meter; 9-a second intake pressure sensor; 10-a one-way valve; 11-pneumatic diaphragm valve; 12-a normal temperature adsorption tank; 13-a heat exchange unit; 14-catalytic oxidation unit.
Detailed Description
For the purpose of making the objects, technical solutions and advantageous effects of the embodiments of the present disclosure more clear, the technical solutions of the embodiments of the present disclosure will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present disclosure, and it is apparent that the described embodiments are some embodiments of the present disclosure, but not all embodiments. Based on the embodiments in this disclosure, all other embodiments that a person of ordinary skill in the art would obtain without making any inventive effort are within the scope of protection of this disclosure.
Example 1
The feed gas processing system in this example was used in inert gas purification. Referring to fig. 1 and 2, the oxygenation system in the present embodiment includes an air intake unit, an oxygenation unit, a catalytic oxidation unit, and a control unit, where the air intake unit and the oxygenation unit are respectively connected to the catalytic oxidation unit.
The air inlet unit is provided with an air inflow monitoring module for monitoring the volume flow of the inert gas raw material gas which is introduced into the catalytic oxidation unit, and the air inflow monitoring module is preferably a mass flowmeter 1. In the preferred scheme, the air inlet pipeline of the air inlet unit is also provided with a branch, and the branch is provided with a pressure monitoring module and a branch switch for monitoring the air inlet pressure of the raw material gas.
The air intake unit is illustratively provided with a manual isolation valve 2, a first intake pressure sensor 3 and a mass flow meter 1. The manual isolation valve 2 and the mass flowmeter 1 are arranged on an air inlet main pipeline, the manual isolation valve 2 is used for opening and closing the raw gas of the air inlet unit pipeline, and the mass flowmeter 1 is used for monitoring the volume flow of the inert gas raw gas which is introduced into the catalytic oxidation unit and feeding back the monitoring result to the control unit in real time. The first intake pressure sensor 3 is provided in a branch of the intake unit pipe for monitoring the intake pressure of the intake unit pipe. The branch of the air inlet unit pipeline is also provided with a first manual valve 4 for opening and closing the branch, and when the first air inlet pressure sensor 3 is damaged, the manual valve can be closed for replacement without affecting the supply of raw gas.
The oxygenation unit is provided with an inlet air quantity control module, preferably a mass flow controller 5, for monitoring and regulating the volumetric flow of oxygen to the catalytic oxidation unit. In the preferred scheme, the gas inlet side of the air inflow control module is further provided with a filtering module for filtering impurities in oxygen, a pressure adjusting module for adjusting the gas pressure at the inlet end of the air inflow control module and a pressure monitoring module for monitoring the gas pressure at the inlet end of the air inflow control module in sequence according to the air inflow direction.
The lines of the oxygenation unit may be provided with a second manual valve 6, a filter 7, a pressure regulating valve with meter 8, a second intake pressure sensor 9, a mass flow controller 5, a one-way valve 10 and a pneumatic diaphragm valve 11, in particular in that order, according to the intake direction.
Wherein the second manual valve 6 is used for controlling the oxygen switch. The filter 7 is used to filter the oxygen particulates and prevent the particulates from damaging the mass flow controller. The pressure regulating valve 8 with a meter is used for regulating the pressure at the inlet end of the mass flow controller 5, and ensuring the pressure to be within the range of the required pressure. The pressure gauge is used for observing the pressure of the oxygen after pressure regulation, so that the oxygen pressure can not be determined after the second air inlet pressure sensor 9 fails. The second inlet pressure sensor 9 is used to monitor whether the pressure at the inlet end of the mass flow controller 5 is within the operating pressure range, and to provide an alarm signal when overpressure or pressure drop occurs and to alarm by an alarm system. The check valve 10 is used to prevent the feed gas from flowing back into the oxygen line. The pneumatic diaphragm valve 11 is used for automatic switching of oxygenation.
The catalytic oxidation unit is a place where the reducing gas impurities in the raw material gas and the oxygen from the oxygenation unit are subjected to oxidation reaction under the action of a catalyst at high temperature. Since nitrogen is the inert shielding gas most commonly used in the industry, it is used as a shielding gas and carrier gas in the manufacture of integrated circuit semiconductors and electric vacuum devices. Thus, in this embodiment, the feed gas is illustratively high purity nitrogen of GB/T8979-2008, wherein the reducing gas impurities are hydrogen, methane and carbon monoxide. The concentrations of hydrogen, methane and carbon monoxide are calculated as the maximum concentration of hydrogen, methane and carbon monoxide contained in the high purity nitrogen in GB/T8979-2008.
The control unit adopts PLC (Programmable Logic Controller ), and the control unit is connected with the air inflow monitoring module and the air inflow control module, and the concentration of hydrogen, methane and carbon monoxide is preset in the control unit. The air inflow monitoring module and the air inflow control module respectively feed back the monitored volume flow a of the raw material gas and the monitored volume flow of the oxygen to the control unit in real time through 4-20mA signals, the control unit calculates the volume flow A of the oxygen required by the reaction of the reducing gas impurities in the raw material gas with the volume flow a according to the concentration of the reducing gas impurities in the raw material gas, and gives out a control signal to control a proportional electromagnetic valve of the mass flow controller to adjust the air inflow of the oxygen to the volume flow A, and the mass flow controller feeds back the flow through a thermal flow monitoring function. When the flow fed back by the mass flow controller is different from the control flow of the control unit, an abnormal oxygen flow alarm is given, so that the pneumatic diaphragm valve 11 is closed, and excessive oxygen is prevented from entering the rear end to affect the purity of the process gas. In a preferred scheme, the control unit controls the air inflow control module to adjust the air inflow of primary oxygen at intervals T according to the volume flow change of the raw gas.
Specifically, the impurity concentrations of high purity nitrogen in GB/T8979-2008 are shown in the following table.
The following high temperature catalytic reactions occur in the catalytic oxidation unit:
CH 4 +2O 2 →2H 2 O+CO 2
2CO+O 2 →2CO 2
2H 2 +O 2 →2H 2 O
in this embodiment, it is assumed that all the gases are ideal gases in the standard condition, and thus the molar ratio of the gases can be directly expressed as a volume ratio. The control unit can calculate the volume ratio of oxygen required by the complete oxidation reaction of each reducing gas impurity according to the volume ratio of each reducing gas impurity in the raw material gas, and then the volume flow of the raw material gas can be calculated by adding the volume ratio of oxygen corresponding to the complete oxidation reaction of each reducing gas impurity.
According to the reaction equation, the oxygen adding amount is calculated according to the content of the maximum reducing gas impurity, and the oxygen in the raw material gas is ignored because the oxygen in the air separation raw material gas is less and the operation stability of the purification system is ensured. Thus, 1ppmCH 4 Requiring addition of 2ppmO 2 1ppmCO requires the addition of 0.5ppmO 2 ，1ppmH 2 Requiring the addition of 0.5ppmO 2 I.e. maximum oxygen addition of 3ppmO 2 。
ppm is the mole fraction or the volume fraction of gas, and after the PLC calculates the required oxygenation amount under the limit state (under the state of the maximum amount of reducing gas impurities) according to the volumetric flow rate of the raw material gas fed back by the mass flowmeter 1, the mass flow controller is controlled to adjust the volumetric flow rate of the oxygen, so that the shortage or the excess oxygenation amount is avoided. The accuracy of the oxygen mass flow controller is 1 minute to adjust the flow for 1 time, so as to improve the accuracy of the oxygen adding flow and the purification stability.
For example, when the volumetric flow rate Q=60 Nm of nitrogen is equal to or lower than 1000slm (standard liter per minute, standard liter/min) in terms of the volumetric flow rate Q per unit time, 3ppm of O 2 Converted into oxygen flow S as follows: 1000×3×10 -6 sml=3×10 -3 sml =3 sccm (standard milliliters/minute). If the volumetric flow rate of the raw gas measured by the mass flowmeter 1 changes, the raw gas can be calculated according to the above formula. And writing a calculation formula into a PLC control program, and automatically calculating the oxygenation flow according to the flow of the raw material gas, so as to adjust and control the oxygen volume flow, thereby ensuring the accuracy of the oxygenation flow and the running stability of the purification system.
Of course, the oxygen adding calculation method in this embodiment is also applicable to other inert gases, such as helium, neon, argon, krypton or xenon, besides nitrogen, wherein the concentration of the reducing gas impurities can be referred to the respective national standards.
The embodiment realizes the linkage of the oxygenation unit and the raw material gas inlet unit, can automatically adjust the flow of oxygen according to the flow of the raw material gas, accurately controls the oxygenation amount, avoids excessive or insufficient oxygenation, and ensures the purity of the purified gas and the stability of the purification process.
The oxygenation and purification process performed in the inert gas purification system including the oxygenation system in this example includes the steps of:
s1, feeding raw gas into a heat exchange unit 13 through a manual isolation valve 2/a bellows valve through an air inlet unit, then feeding the raw gas into a catalytic oxidation unit 14 for high-temperature catalytic reaction, and feeding the monitored volumetric flow a of the raw gas back to a control unit by an air inlet amount monitoring module in the air inlet unit;
s2, the control unit calculates the volume flow A of oxygen required by the reaction of the reducing gas impurities in the volume flow a according to the concentration of the reducing gas impurities in the raw material gas;
s3, the control unit controls an air inflow control module in the oxygenation unit to adjust the volume flow of oxygen to be the volume flow A, and oxygen enters a pipeline of the oxygenation unit through the second manual valve 6 and enters the catalytic oxidation unit through the filter 7, the one-way valve 10 and the pneumatic diaphragm valve 11.
In a more preferred embodiment, the method further comprises the step of compensating the volume flow of oxygen fed to the catalytic oxidation unit: the volume flow of oxygen calculated by the control unit is added with a compensation factor which can be set to a volume flow corresponding to 0 to 0.2ppm of oxygen, preferably to a volume flow corresponding to 0.1ppm of oxygen, for compensating for oxygen deficiency due to instrument deviation.
After the high-temperature catalytic reaction of the raw material gas is finished, the raw material gas enters the heat exchange unit again to exchange heat with the air inlet, enters the normal-temperature adsorption tank 12 through the pneumatic valve to be adsorbed and purified after the heat exchange, and then enters the back-end user process equipment through the pneumatic valve.
Example 2
The raw material gas processing system in this embodiment is provided with a detection unit for detecting the concentration of the reducing gas impurity and the oxygen concentration of the raw material gas before and after the catalytic oxidation reaction, for example, with a detection device such as an oxygen analyzer or a chromatograph, and the rest of the arrangement is referred to in embodiment 1.
The detection unit is connected with the control system, and the detected data of the concentration of the reducing gas impurity and the concentration of the oxygen in the raw material gas before the catalytic oxidation reaction and the oxygen concentration of the purified gas obtained after the catalytic oxidation reaction are fed back to the control unit through 4-20mA signals.
In this embodiment, the inert gas is also illustratively selected from the group consisting of high purity nitrogen in GB/T8979-2008, and the reducing gas impurities include hydrogen, methane and carbon monoxide. Of course, the system of this embodiment can also be used for purification of other inert gases. The volume flow of the initial oxygen gas fed to the catalytic oxidation unit is also calculated in the same manner as in example 1:
and calculating the volume ratio of oxygen required by the complete oxidation reaction of each reducing gas impurity according to the volume ratio of each reducing gas impurity in the raw material gas, and then adding the volume ratio of oxygen corresponding to the complete oxidation reaction of each reducing gas impurity to the volume flow of the raw material gas to obtain the volume flow of oxygen.
However, in this embodiment, the control unit will control the air intake control module to accurately adjust the volumetric flow of primary oxygen according to the change of the oxygen concentration in the purified gas fed back by the detection unit at intervals T.
The oxygenation and purification process performed in the inert gas purification system including the feed gas treatment system in this example includes the steps of:
s0. detecting unit detects the concentration of the reducing gas impurity and the concentration of the original oxygen in the raw material gas, and the oxygen concentration of the raw material gas after catalytic oxidation reaction and feeds back to the control unit;
s1, feeding raw gas into a heat exchange unit 13 through a manual isolation valve 2/a bellows valve through an air inlet unit, then feeding the raw gas into a catalytic oxidation unit 14 for high-temperature catalytic reaction, and feeding the monitored volumetric flow a of the raw gas back to a control unit by an air inlet amount monitoring module in the air inlet unit;
s2, the control unit calculates the volume flow A of oxygen required by the reaction of the reducing gas impurities in the volume flow a according to the concentration of the reducing gas impurities in the raw material gas;
s3, the control unit controls an air inflow control module in the oxygenation unit to adjust the volume flow of oxygen to volume flow A, and oxygen enters a pipeline of the oxygenation unit through the second manual valve 6 and enters the catalytic oxidation unit through the filter 7, the one-way valve 10 and the pneumatic diaphragm valve 11;
s4, the control unit controls the air inflow control module to accurately adjust the volume flow of primary oxygen every time interval T (such as one minute) according to the change of the oxygen concentration in the purified gas:
the detection unit detects the oxygen concentration of the purified gas obtained after the catalytic oxidation reaction at each time interval T and feeds back the result to the control unit,
the control unit compares the oxygen concentration of the purified gas before and after the time interval T,
when residual oxygen is detected in the purified gas after the time interval T, the volume flow a is adjusted to: the volume flow of oxygen in the purified gas after the time interval T is subtracted from the volume flow of oxygen which is introduced into the catalytic oxidation unit before the time interval T;
when no oxygen is detected in the purified gas after the time interval T, the volume flow a is adjusted to: the oxygen volume flow which is introduced into the catalytic oxidation unit before the time interval T is added with the oxygen volume flow which is reduced by the purified gas after the time interval T;
when no oxygen is detected in the purified gas after time interval T and the oxygen volumetric flow is not reduced when adjusted before time interval T, then the volumetric flow a is adjusted to: the volume flow of oxygen introduced into the catalytic oxidation unit before the time interval T is increased by the reduction in the volume flow of oxygen in the previous adjustment, i.e. by the corresponding reduction in volume flow when the volume flow of oxygen in the last adjustment is reduced.
In this embodiment, the oxygen volume flow adjusted before the time interval T is used for the catalytic oxidation reaction in the time range T, and the oxygen volume flow adjusted after the time interval T is used for the catalytic oxidation reaction in the next time range T.
After the high-temperature catalytic reaction of the raw material gas is finished, the raw material gas enters the heat exchange unit again to exchange heat with the air inlet, enters the normal-temperature adsorption tank 12 through the pneumatic valve to be adsorbed and purified after the heat exchange, and then enters the back-end user process equipment through the pneumatic valve.
In a more preferred embodiment, the present embodiment also comprises the step of compensating the volumetric flow rate of oxygen fed to the catalytic oxidation unit: the volume flow of oxygen calculated by the control unit is added with a compensation factor which can be set to a volume flow corresponding to 0 to 0.2ppm of oxygen, preferably to a volume flow corresponding to 0.1ppm of oxygen, for compensating for oxygen deficiency due to instrument deviation.
The detection unit is arranged to detect the actual concentration of the oxygen in the raw material gas before and after catalytic oxidation, and the oxygen adding amount actually required is calculated and controlled according to the change of the oxygen concentration of the raw material gas after catalytic oxidation, so that the operation is more flexible, and the accurate control of the oxygen amount is further realized.
The above embodiments are merely exemplary descriptions of the present disclosure, and are not intended to limit the scope of the disclosure, and various modifications and improvements made by those skilled in the art to the technical solutions of the present disclosure should fall within the protection scope determined by the present disclosure without departing from the design spirit of the present disclosure.
Claims (10)
1. A feed gas processing system, comprising
The air inlet unit is provided with an air inflow monitoring module which is used for monitoring the volume flow of raw gas which is introduced into the catalytic oxidation unit, wherein the raw gas is inert gas containing reducing gas impurities capable of reacting with oxygen;
the oxygen adding unit is provided with an air inflow control module which is used for monitoring and adjusting the volume flow of oxygen introduced into the catalytic oxidation unit;
a catalytic oxidation unit, wherein the reducing gas impurities and the oxygen in the raw material gas undergo oxidation reaction in the catalytic oxidation unit to obtain purified gas;
the control unit is connected with the air inflow monitoring module and the air inflow control module and used for controlling the air inflow control module to adjust the volume flow of the oxygen according to the concentration of the reducing gas impurities in the raw gas;
the control unit controls the air inflow control module to adjust the volume flow A of the oxygen which is introduced into the catalytic oxidation unit once at intervals of T according to the change of the oxygen concentration of the purified gas:
when residual oxygen is detected in the purified gas after a time interval T, the volume flow a is adjusted to: the volume flow of oxygen in the purified gas after the time interval T is subtracted from the volume flow of oxygen which is introduced into the catalytic oxidation unit before the time interval T;
when no oxygen is detected in the purified gas after a time interval T, the volume flow a is adjusted to: the volume flow of oxygen to the catalytic oxidation unit before the time interval T is added to the reduced volume flow of oxygen of the purified gas after the time interval T.
2. The feed gas processing system of claim 1, wherein when no oxygen is detected in the purified gas after time interval T and the oxygen volumetric flow is not reduced when adjusted prior to time interval T, the volumetric flow a is adjusted to: the volume flow of oxygen introduced into the catalytic oxidation unit before the time interval T is increased by the corresponding volume flow reduction when the volume flow of the most recently adjusted oxygen is reduced.
3. The feed gas processing system of claim 1, wherein the feed gas comprises at least two of the reducing gas impurities;
the control unit calculates the volumetric flow rate of the oxygen in the following manner:
calculating the oxygen volume ratio required by the complete oxidation reaction of each reducing gas impurity according to the volume ratio of each reducing gas impurity in the raw material gas,
and multiplying the sum of the oxygen volume ratios corresponding to the complete oxidation reaction of the reducing gas impurities by the volume flow of the raw material gas.
4. A feed gas processing system according to claim 3, wherein the feed gas comprises high purity nitrogen or ultra-high purity nitrogen in CB/T8979.
5. The feed gas processing system according to claim 3, further comprising a detection unit connected to the control unit for detecting at least an oxygen concentration of the feed gas before the catalytic oxidation reaction and an oxygen concentration of the purified gas obtained after the catalytic oxidation reaction.
6. The feed gas processing system of claim 5, wherein the volumetric flow rate of oxygen is:
and adding the volume flow of the oxygen calculated by the control unit with a compensation coefficient, wherein the value of the compensation coefficient is the volume flow corresponding to 0-0.2 ppm of oxygen.
7. A process for treating a feed gas in a feed gas treatment system according to any one of claims 1 to 6, comprising the steps of:
s1, feeding back the monitored volumetric flow a of the raw gas to a control unit by an air inflow monitoring module in an air inflow unit;
s2, the control unit calculates the volume flow A of oxygen required by the reaction of the reducing gas impurities in the volume flow a according to the concentration of the reducing gas impurities in the raw material gas;
s3, the control unit controls an air inflow control module in the oxygenation unit to adjust the volume flow of oxygen to the volume flow A.
8. The feed gas processing method according to claim 7, wherein the control unit calculates the volume flow a as follows:
and calculating the oxygen volume ratio required by the complete oxidation reaction of each reducing gas impurity according to the volume ratio of each reducing gas impurity in the raw material gas, and multiplying the sum of the oxygen volume ratios corresponding to the complete oxidation reaction of each reducing gas impurity by the volume flow of the raw material gas.
9. The feed gas processing method according to claim 8, further comprising the step of adjusting the volume flow a once every time interval T:
the detection unit detects the oxygen concentration of the purified gas obtained after the catalytic oxidation reaction at intervals of T and feeds back the result to the control unit,
the control unit compares the oxygen concentration of the purified gas before and after the time interval T,
when residual oxygen is detected in the purified gas after a time interval T, the volume flow a is adjusted to: the volume flow of oxygen in the purified gas after the time interval T is subtracted from the volume flow of oxygen which is introduced into the catalytic oxidation unit before the time interval T;
when no oxygen is detected in the purified gas after a time interval T, the volume flow a is adjusted to: the oxygen volume flow which is introduced into the catalytic oxidation unit before the time interval T is added with the oxygen volume flow which is reduced by the purified gas after the time interval T;
when no oxygen is detected in the purified gas after time interval T and the oxygen volumetric flow is not reduced when adjusted before time interval T, then the volumetric flow a is adjusted to: the volume flow of oxygen introduced into the catalytic oxidation unit before the time interval T is increased by the corresponding volume flow reduction when the volume flow of the most recently adjusted oxygen is reduced.
10. The feed gas processing method according to claim 7, further comprising the step of compensating the volumetric flow rate of oxygen gas:
the volume flow A is as follows: and the volume flow of the oxygen calculated by the control unit is added with a compensation coefficient, wherein the value of the compensation coefficient is the volume flow corresponding to 0-0.2 ppm of oxygen.
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| CN87103563A (en) * | 1986-04-16 | 1988-01-06 | Veg气体研究所公司 | From sulfurous gas, reclaim the method for sulphur |
| CN110282608A (en) * | 2019-07-18 | 2019-09-27 | 大连中鼎化学有限公司 | A kind of purification devices and its technique for nitrogen, oxygen, argon gas and helium |
| CN209906346U (en) * | 2019-03-18 | 2020-01-07 | 华谊高新纯化技术(大连)有限公司 | Ultra-pure purification system of nitrogen gas, argon gas, oxygen |
| CN117180972A (en) * | 2023-08-01 | 2023-12-08 | 四川省达科特能源科技股份有限公司 | Air supplementing control method for catalytic oxidative dehydrogenation reaction in dehydrogenation system |
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Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN87103563A (en) * | 1986-04-16 | 1988-01-06 | Veg气体研究所公司 | From sulfurous gas, reclaim the method for sulphur |
| CN209906346U (en) * | 2019-03-18 | 2020-01-07 | 华谊高新纯化技术(大连)有限公司 | Ultra-pure purification system of nitrogen gas, argon gas, oxygen |
| CN110282608A (en) * | 2019-07-18 | 2019-09-27 | 大连中鼎化学有限公司 | A kind of purification devices and its technique for nitrogen, oxygen, argon gas and helium |
| CN117180972A (en) * | 2023-08-01 | 2023-12-08 | 四川省达科特能源科技股份有限公司 | Air supplementing control method for catalytic oxidative dehydrogenation reaction in dehydrogenation system |
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