JP6768098B2 - Gas refinery and its operation method - Google Patents

Description

The present invention relates to a gas purification apparatus and an operation method thereof, and more specifically, includes a heater for heating the purification target gas to a predetermined catalytic reaction temperature to be introduced into a catalytic reactor that catalyzes an impurity component in the purification target gas. Regarding gas purification equipment and its operation method.

As a means for purifying by removing impurity components contained in the gas to be purified, a gas purification device in which a catalyst cylinder filled with a catalyst and an adsorption cylinder filled with an adsorbent are combined is known (for example, a patent). See Reference 1.). For example, when removing hydrocarbons, which are impurities contained in nitrogen gas, which is the gas to be purified, nitrogen gas heated by a heater is introduced into the catalyst cylinder, and methane is converted to water and carbon dioxide by catalytic reaction. After decomposing into the above, purified nitrogen gas is obtained by adsorbing and removing the generated water and carbon dioxide as components to be removed with an adsorption cylinder.

Japanese Unexamined Patent Publication No. 2012-51753

However, in the conventional gas purification device using the catalyst cylinder, in order to bring the gas to be refined into contact with the catalyst at a high temperature, a heater is arranged on the upstream side (previous stage) of the catalyst cylinder and the gas to be refined to be introduced into the catalyst cylinder. Had to be heated in a heater to the temperature required for the catalytic reaction. For this reason, the energy for heating the gas to be refined is enormous, and the running cost is greatly affected particularly in the semiconductor manufacturing equipment using a large amount of the refined gas.

Therefore, an object of the present invention is to provide a gas purification apparatus capable of reducing the running cost by suppressing the amount of energy required for the gas heater and an operation method thereof.

In order to achieve the above object, the gas purification apparatus of the present invention has a gas heater that heats the gas to be refined and an impurity component in the gas to be refined heated by the gas heater by catalytic reaction to form a component to be removed. In a gas purification apparatus provided with a catalyst cylinder for purifying and a purifier for removing the component to be removed in the gas to be refined derived from the catalyst cylinder, a gas introduction path for introducing the gas to be refined into the gas heater and a gas introduction route. A gas introduction valve provided in the gas introduction path, a refiner inlet path for introducing the gas derived from the catalyst cylinder into the refiner, and a refiner outlet path for introducing the refined gas purified by the refiner. , A bypass path branched from the upstream side of the gas introduction valve and connected to the refiner inlet path or the refiner outlet path, a bypass valve provided in the bypass path, and upstream of the branch portion of the bypass path. It is provided with an analyzer that measures the concentration of an impurity component in the gas to be purified flowing in the gas introduction path and controls the opening and closing of the gas introduction valve and the bypass valve according to the measured concentration of the impurity component . When the impurity component concentration measured by the analyzer is higher than the preset concentration, the analyzer controls the bypass valve to be closed and the gas introduction valve to be opened, and the analyzer is used. When the measured impurity component concentration is lower than the preset set concentration, the gas introduction valve is closed and the bypass valve is controlled to be opened .

Further, the gas purification apparatus of the present invention includes a detour route in which the gas introduction valve connects the upstream side and the downstream side of the gas introduction valve, and the detour route adjusts the gas flow rate flowing through the detour route. It is characterized by having a flow control valve.

Further, in the operation method of the gas purification apparatus of the present invention, a gas heater for heating the purification target gas and a catalyst for catalytically reacting an impurity component in the purification target gas heated by the gas heater to be a removal target component. A cylinder and a purifier for removing the component to be removed in the gas to be refined derived from the catalyst cylinder are provided, and the gas introduction path for introducing the gas to be refined into the gas heater and the gas introduction path are provided. The gas introduction valve, the refiner inlet path for introducing the gas drawn from the catalyst cylinder into the refiner, the refiner outlet path for taking out the refined gas refined by the refiner, and the gas introduction valve. A bypass path branched from the upstream side and connected to the refiner inlet path or the refiner outlet path, a bypass valve provided in the bypass path, and the gas introduction provided upstream of the branch portion of the bypass path. A method of operating a gas purification apparatus provided with an analyzer that measures the concentration of impurity components in the gas to be refined flowing in the path and controls the opening and closing of the gas introduction valve and the bypass valve according to the measured concentration of the impurity components. When the concentration of the impurity component measured by the analyzer is higher than the preset concentration, the bypass valve is closed and the gas introduction valve is opened to allow the purification target gas to pass through the gas introduction path. When the concentration of impurity components introduced into the gas heater and measured by the analyzer is lower than the preset concentration, the gas to be refined is gas by closing the gas introduction valve and opening the bypass valve. Is not introduced into the gas heater, but is introduced into the refiner inlet path or the refiner outlet path through the bypass path.

Further, the method of operating the gas purification apparatus of the present invention is characterized in that when the gas introduction valve is closed, the gas to be refined at a preset flow rate is introduced into the gas heater.

According to the present invention, when the impurity component concentration measured by the analyzer is lower than the preset set concentration, the purification target gas can be prevented from being introduced into the heater, so that the purification target gas can be heated by the heater. No energy is required. As a result, the running cost of the gas purification apparatus can be reduced.

It is a system diagram which shows an example of one form of the gas purification apparatus of this invention. It is a system diagram of the gas purification apparatus used in the experimental example.

FIG. 1 is a system diagram showing an example of a mode of the gas purification apparatus of the present invention. In the gas purification apparatus shown in this embodiment, the removal target component (impurity component) contained in the raw material gas (purification target gas) supplied from the raw material gas supply path 11 is removed by the refiner 13 by a catalytic reaction in the catalyst cylinder 12. The raw material gas is purified by converting it into a possible component and removing the component to be removed by the refiner 13, and the high temperature after the catalytic reaction derived from the catalyst cylinder 12 is on the upstream side of the catalyst cylinder 12. A heat exchanger 14 that recovers heat by exchanging heat between the gas and the raw material gas, and a gas heater 15 that heats the raw material gas to a temperature required for a catalytic reaction are provided.

The catalyst cylinder 12 has a heater and a heat insulating layer (neither of them is shown), and the heater of the catalyst cylinder 12 is not intended to heat the catalyst in the cylinder, but is a catalyst together with the heat insulating layer. The catalyst is provided to prevent the temperature from dropping, and the catalyst reacts by coming into contact with the high-temperature raw material gas heated by the heat exchanger 14 and the gas heater 15. Therefore, the gas heater 15 is provided with a heater having a capacity capable of heating the entire amount of the raw material gas supplied from the raw material gas supply path 11 to a predetermined catalytic reaction temperature, and is provided at the outlet portion of the gas heater 15 or the outlet portion of the gas heater 15. The heater output is automatically controlled according to the measured temperature of a thermometer (not shown) provided at the inlet of the catalyst cylinder 12.

The raw material gas supply path 11 is branched into a gas introduction path 16 and a bypass path 17, and the gas introduction path 16 is transferred from the heat exchanger 14 and the gas heater 15 to the catalyst cylinder 12 via the gas introduction valve 18. The bypass path 17 that bypasses the catalyst cylinder 12 and the like is connected to the refiner inlet path 20 provided on the inlet side of the refiner 13 via the bypass valve 19.

Further, on the upstream side of the branch portion of the bypass path 17 in the raw material gas supply path 11, the concentration of the impurity component contained in the raw material gas flowing in the raw material gas supply path 11 is measured, and the gas is introduced. An analyzer 21 for controlling the opening and closing of the valve 18 and the bypass valve 19 is provided. When the measured impurity component concentration is higher than the preset setting concentration, the analyzer 21 closes the bypass valve 19 and opens the gas introduction valve 18, and the measured impurity component concentration is preset. When the concentration is lower than the set concentration, a valve open / close control unit for closing the gas introduction valve 18 and opening the bypass valve 19 is provided.

Further, the gas introduction path 16 is provided with a detour route 22 connecting the upstream side and the downstream side of the gas introduction valve 18, and the detour route 22 is provided with a gas flow rate flowing through the detour route 22. A flow rate control valve 23 for adjusting and a flow meter 24 for confirming the flow rate are provided. This detour path 22 is for introducing a part of the raw material gas into the catalyst cylinder 12 via the heat exchanger 14 and the gas heater 15 when the gas introduction valve 18 is fully closed. By introducing a part of the raw material gas heated and heated by the heat exchanger 14 and the gas heater 15 into the catalyst cylinder 12, the catalyst in the catalyst cylinder 12 is heated and maintained at a predetermined catalyst reaction temperature. ing.

When the concentration of impurity components in the raw material gas measured by the analyzer 21 is higher than the set concentration, the gas purification apparatus configured in this way closes the bypass valve 19 and opens the gas introduction valve 18 to gas the entire amount of the raw material gas. It is introduced into the heat exchanger 14 from the introduction path 16 for primary heating, and further heated to a predetermined catalytic reaction temperature by secondary heating with the gas heater 15, and then introduced into the catalyst cylinder 12 in a high temperature state to provide a catalyst. By the reaction, the impurity component in the raw material gas is converted into a component that can be removed by the purifier 13 (component to be removed). The high-temperature raw material gas containing the component to be removed is cooled by heat recovery in the heat exchanger 14 and then introduced into the refiner 13 through the refiner inlet path 20 by an adsorbent or the like in the refiner 13. By removing the component to be removed, the purified gas has the component to be removed in the raw material gas removed.

The purifier 13 can employ means according to the components to be removed, and usually, a temperature fluctuation adsorption separation device (TSA device) or a pressure fluctuation adsorption separation device (PSA device) using an adsorbent is used. Can be done. In the case of these TSA devices and PSA devices, by arranging a plurality of adsorption cylinders and sequentially switching between the adsorption step and the regeneration step, the adsorption and removal of the component to be removed from the raw material gas can be continuously performed.

On the other hand, when the impurity component concentration measured by the analyzer 21 is lower than the set concentration, the gas introduction valve 18 is closed, the bypass valve 19 is opened, the raw material gas is introduced from the bypass path 17 into the refiner inlet path 20, and the refiner 13 is introduced. Introduce directly to. That is, since the raw material gas is not heated by the gas heater 15, the energy for heating the raw material gas in the gas heater 15 becomes unnecessary, and for example, the power consumption can be reduced.

At this time, the catalyst in the catalyst cylinder 12 is heated by heating an appropriate amount of the raw material gas through the flow control valve 23 of the detour path 22 with the heat exchanger 14 and the gas heater 15 and then introducing the gas into the catalyst cylinder 12. It is possible to heat to a predetermined catalytic reaction temperature with a fixed amount of raw material gas, and it is possible to prevent the temperature of the catalyst from dropping. In this case, the total amount of raw material gas than when heated in a gas heater 15, since less material amount of gas heated by the gas heater 15, the raw material gas heat amount in the gas heater 15 is much less Therefore, the energy for heating the raw material gas can be reduced. As a result, when the concentration of impurity components in the raw material gas rises and the path of the raw material gas is switched from the bypass path 17 to the gas introduction path 16, the catalytic reaction in the catalyst cylinder 12 can be immediately started, and no reaction occurs. Impurities will not flow out of the catalyst cylinder 12 at a high concentration.

Further, instead of connecting the downstream of the bypass path 17 to the refiner inlet path 20, it is connected to a path provided on the outlet side of the refiner 13, and the impurity component concentration in the raw material gas measured by the analyzer 21. When the value is low, the raw material gas can be flowed from the bypass path to the outlet side of the refiner 13. Further, when the flow rate adjustable valve is used for the gas introduction valve 18 and the bypass valve 19, and the impurity component concentration in the raw material gas measured by the analyzer 21 is equal to or slightly higher than the set concentration, the gas flows into the gas introduction path 16. It is also possible to adjust the flow rate of the raw material gas and the flow rate of the gas flowing through the bypass path 17 so that the raw material gas flows through both paths at an appropriate ratio at the same time. As a result, the energy for heating the raw material gas can be reduced while maintaining the purity of the gas derived from the refining apparatus.

For example, when methane contained in nitrogen gas is removed and purified to obtain high-purity nitrogen gas having a methane content of less than 10 ppb, the raw material nitrogen gas is used in a heat exchanger 14 and a gas heater 15 at about 200 to 400 ° C. After heating and raising the temperature, the gas is introduced into the catalyst cylinder 12 and brought into contact with the oxidation catalyst filled in the catalyst cylinder 12, and methane is decomposed into water and carbon dioxide by an oxidation reaction at a high temperature. Moisture and carbon dioxide generated by the catalytic reaction, and the components to be removed originally contained in the raw material nitrogen gas are removed by an adsorbent filled in the adsorption cylinder of the refiner 13, for example, alumina or molecular sieves. As a result, high-purity nitrogen gas having a methane content of less than 10 ppb can be obtained.

At this time, if the concentration of methane contained in the raw material nitrogen gas is less than 10 ppb from the beginning, it can be used as it is as high-purity nitrogen gas without converting methane into water and carbon dioxide by catalytic reaction. , It is not necessary to heat the raw material nitrogen gas and introduce it into the catalyst cylinder 12. Therefore, the energy consumption in the gas heater 15 can be reduced by guiding the raw material nitrogen gas to the downstream side of the catalyst cylinder 12 without passing through the gas heater 15 and the catalyst cylinder 12 by using the bypass path 17.

Next, the result of conducting an experiment for confirming the effect of the present invention using the experimental purification apparatus having the configuration shown in FIG. 2 will be described. In the following description, the same components as the components of the gas purification apparatus shown in the above-described example will be designated by the same reference numerals, and detailed description thereof will be omitted.

The gas to be refined was nitrogen gas for semiconductor manufacturing equipment, and the impurity component was methane, which is a type of hydrocarbon. As shown in FIG. 2, the experimental refiner is provided with a methane introduction unit 31 for introducing methane on the upstream side of the analyzer 21, and a refiner outlet path provided on the outlet side of the refiner 13. The flow meter 33 and the lead-out gas flow control valve 34 were provided in the 32, and the same analyzer 35 as the supply side was provided so that the methane concentration could be measured.

The catalyst cylinder 12 was filled with a Pd-based catalyst, and a heater provided in the catalyst cylinder 12 automatically controlled the surface temperature to 300 ° C. Further, the gas heater 15 automatically controlled the heater so that the gas temperature on the outlet side of the heater was 300 ° C. The catalyst cylinder 12, the gas heater 15, and the piping through which the high-temperature gas flows were covered with a heat insulating material having a thickness of 100 mm in order to prevent burns and excessive power consumption due to heat dissipation. Further, the refiner 13 is laminated and filled with molecular sieves and alumina to remove carbon dioxide and water, which are components to be removed, which are generated by the catalytic reaction in the catalyst cylinder 12.

First, as a conventional example, the gas introduction valve 18 was opened with the bypass valve 19 closed, and the gas flow rate was adjusted to 20 Nm ³ / h in the standard state by the lead-out gas flow rate control valve 34 provided at the outlet of the device. The nitrogen gas supply pressure from the raw material gas supply path 11 at this time was 0.8 MPaG. The total amount of the supplied nitrogen gas was heated to 300 ° C. by the gas heater 15 and introduced into the catalyst cylinder 12 for 3 hours to measure the power consumption. As a result, the power consumption was 4 kW.

On the other hand, as an experimental example of the method of the present invention, the operation was performed with the flow rate and pressure of the nitrogen gas and the temperature of the catalyst cylinder 12 being the same as those of the comparative example, except that nitrogen gas having a methane content of less than 10 ppb was used. Further, the flow rate control valve 23 is adjusted so that the amount of nitrogen gas flowing through the detour path 22 is 1 L / min with the gas introduction valve 18 closed, and a constant amount of nitrogen gas is released even when the gas introduction valve 18 is closed. It was made to flow toward the gas heater 15. The gas introduction valve 18 and the bypass valve 19 are set to switch between opening and closing by setting the set concentration of the analyzer 21 to 10 ppb.

First, the operation was performed without adding methane from the methane introduction unit 31. At this time, since the methane measurement concentration of the analyzer 21 is less than 10 ppb, the gas introduction valve 18 is closed and the bypass valve 19 is opened, and substantially all of the supplied nitrogen gas passes through the bypass path 17 to the gas heater 15. Is in a state where 1 L / min of nitrogen gas flows. The methane concentration measured by the analyzer 35 provided in the refiner outlet path 32 was also less than 10 ppb.

After 1 hour, methane was added at 1 sccm from the methane introduction section 31 so that the methane concentration in the nitrogen gas became 3 ppm. At this time, since the methane measurement concentration of the analyzer 21 exceeded the set concentration of 10 ppb, the bypass valve 19 was automatically switched to open and the gas introduction valve 18 was automatically switched to open, and the entire amount of nitrogen gas to which methane was added was introduced into gas. It will flow to the route 16. As a result, methane is converted into carbon dioxide and water by the catalytic reaction in the catalyst cylinder 12, and the generated carbon dioxide and water are adsorbed and removed by the refiner 13. In this state, the methane concentration measured by the analyzer 35 of the refiner outlet path 32 was less than 10 ppb, and it was confirmed that methane, which is an impurity component, was reliably removed.

When the addition of methane was stopped in 1 hour, the concentration of methane measured by the analyzer 21 was less than the set concentration of 10 ppb, so that the gas introduction valve 18 was closed and the bypass valve 19 was automatically switched to open. Therefore, 1 L / min of nitrogen gas flows through the gas heater 15. The operation was carried out for 1 hour in this state, and the power consumption was measured for a total of 3 hours (of which 1 hour was added with methane). As a result, the power consumption was 1.5 kW.

Therefore, the power consumption can be reduced to 1 / 2.7 as compared with the conventional case. The amount of power consumption that can be reduced differs depending on conditions such as the flow rate of nitrogen gas flowing through the flow rate control valve 23 to the gas heater 15 when the gas introduction valve 18 is closed. For example, the flow rate of nitrogen gas as a raw material or The effect of reducing power consumption also differs depending on the purity and the set concentration of the analyzer 21 for switching between the gas introduction valve 18 and the bypass valve 19.

Further, by using a valve whose opening degree can be adjusted as the gas introduction valve 18, the gas introduction valve 18 can be used even under the condition that the gas introduction valve 18 is closed without using the bypass path 22 or the flow rate control valve 23. A part of the raw material gas can be flowed through the gas introduction path 16 in a slightly open state. Further, the analyzer 21 is as close to the supply source on the upstream side of the raw material gas supply path 11 as possible in order to reliably switch between the gas introduction valve 18 and the bypass valve 19 even when the impurity component concentration changes abruptly. It is preferable to provide it at a position.

11 ... Raw material gas supply path, 12 ... Catalyst cylinder, 13 ... Purifier, 14 ... Heat exchanger, 15 ... Gas heater, 16 ... Gas introduction path, 17 ... Bypass path, 18 ... Gas introduction valve, 19 ... Bypass valve , 20 ... Purifier inlet path, 21 ... Analyzer, 22 ... Detour path, 23 ... Flow control valve, 24 ... Flow meter, 31 ... Methane introduction section, 32 ... Purifier outlet path, 33 ... Flow meter, 34 ... Derivation Gas flow control valve, 35 ... Analyzer

Claims (4)

In the gas heater that heats the gas to be refined, the catalyst cylinder that catalyzes the impurity component in the gas to be refined heated by the gas heater to be the component to be removed, and the gas to be refined derived from the catalyst cylinder. In a gas purification apparatus provided with a purifier for removing the component to be removed, a gas introduction path for introducing the gas to be refined into the gas heater, a gas introduction valve provided in the gas introduction path, and the catalyst. The refiner inlet path for introducing the gas drawn out from the cylinder into the refiner, the refiner outlet path for taking out the refined gas refined by the refiner, and the refiner branching from the upstream side of the gas introduction valve. In the bypass path connected to the inlet path or the outlet path of the refiner, the bypass valve provided in the bypass path, and the gas to be purified which is provided on the upstream side of the branch portion of the bypass path and flows in the gas introduction path. The analyzer is provided with an analyzer that measures the impurity component concentration and controls the opening and closing of the gas introduction valve and the bypass valve according to the measured impurity component concentration, and the analyzer has the impurity component concentration measured by the analyzer. When the concentration is higher than the preset set concentration, the bypass valve is closed and the gas introduction valve is controlled to open, and the impurity component concentration measured by the analyzer is lower than the preset set concentration. A gas purification apparatus characterized in that the gas introduction valve is closed and the bypass valve is opened when the concentration is high . The gas introduction valve includes a detour path connecting the upstream side and the downstream side of the gas introduction valve, and the detour path includes a flow rate control valve for adjusting the gas flow rate flowing through the detour path. The gas purification apparatus according to claim 1. In the gas heater that heats the gas to be refined, the catalyst cylinder that catalyzes the impurity component in the gas to be refined heated by the gas heater to be the component to be removed, and the gas to be refined derived from the catalyst cylinder. It is provided with a purifier for removing the component to be removed, a gas introduction path for introducing the gas to be refined into the gas heater, a gas introduction valve provided in the gas introduction path, and a lead-out from the catalyst cylinder. The refiner inlet path for introducing gas into the refiner, the refiner outlet path for deriving the refined gas refined by the refiner, and the refiner inlet path or the refiner inlet path branched from the upstream side of the gas introduction valve. The concentration of impurity components in the bypass path connected to the outlet path of the refiner, the bypass valve provided in the bypass path, and the purification target gas provided upstream from the branch portion of the bypass path and flowing in the gas introduction path. In the operation method of the gas purification apparatus provided with the gas introduction valve and the analyzer that controls the opening and closing of the bypass valve according to the measured and measured impurity component concentration, the impurity component concentration measured by the analyzer is determined. When the concentration is higher than the preset set concentration, the gas to be purified is introduced into the gas heater through the gas introduction path by closing the bypass valve and opening the gas introduction valve, and measured by the analyzer. When the concentration of the purified impurity component is lower than the preset concentration, the bypass valve is closed and the bypass valve is opened without introducing the purification target gas into the gas heater. A method of operating a gas purifier, which comprises introducing the gas purifier into the refiner inlet route or the refiner outlet route through a route. The method for operating a gas purification apparatus according to claim 3, wherein when the gas introduction valve is closed, the gas to be refined at a preset flow rate is introduced into the gas heater.

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