JP2009226355A - Reduction treatment device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a reduction treatment device which can determine the end of reduction at a low cost in a short time. <P>SOLUTION: A water level gage 20 is set so that the amount of water produced after gas-liquid separation determined by the amount of a CO modification catalyst 15 packed in a catalyst reactor 14 can be detected by a liquid level in a cooler 17. When it is detected that the level of the produced water in the cooler 17 reaches a detection level by the water level gage 20, a cutoff valve 21 is opened by a control device 24 to discharge the produced water in the cooler 17 into a produced water storage tank 22, the amount of the produced water discharged in the produced water storage tank 22 is measured with a balance 23, and the end of reduction is determined from the results of the measurement. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a catalytic reduction device for a reactor filled with a catalyst that requires a reduction treatment in advance.

  A fuel cell system generally generates electricity by steam-reforming a fuel such as city gas, LPG (Liquefied Petroleum Gas), kerosene, etc. to extract hydrogen, and chemically reacting the extracted hydrogen with oxygen in the air. However, a plurality of catalytic reactors are required for reforming the fuel. For example, a reformer of a phosphoric acid fuel cell system includes a desulfurizer for removing sulfur contained in fuel, a reformer for generating hydrogen from the desulfurized fuel, and a fuel cell body cover. It is composed of a CO converter that reduces carbon monoxide, which is a toxic substance, to 1% or less.

  As the above-described reformer, there is known a method of removing organic sulfur compounds such as dimethyl sulfide and tertiary butyl mercaptan contained in city gas by a hydrodesulfurization method in a desulfurizer. In recent years, a desulfurization method using a copper zinc-based catalyst has also been developed. In the reformer, after removing sulfur with a desulfurizer, a hydrogen-rich reformed gas is obtained by a steam reforming reaction that generates hydrogen. The hydrogen-rich reformed gas is introduced into a CO converter using a copper zinc-based catalyst in the subsequent stage and the CO concentration is reduced to 1% or less, and then supplied to the fuel cell body. The catalyst used in these catalytic reactors needs to be subjected to a reduction treatment in advance in order to exhibit performance. For example, a copper zinc-based catalyst used in a desulfurizer and a CO converter is a typical catalyst that is generally used after reduction treatment (see, for example, Patent Document 1).

The reduction operation of the copper-zinc catalyst is a reaction for changing CuO (copper oxide) to Cu (metal copper), and involves a remarkable exothermic reaction.
CuO + H ₂ → Cu + H ₂ 0 −20.7 (kcal / mol) (1)
Therefore, in order to avoid temperature runaway during the catalyst reduction operation, nitrogen is used as the carrier gas as the inert gas, the reducing gas is mixed at a low concentration, and the temperature of the catalyst layer installed in the catalyst layer is measured. However, it was important to control the reduction temperature so that no abnormal heat generation occurred. GHSV (Gas Hourly Space Velocity, space velocity of residual concentration) when carrying out the reduction operation is set in the range of 200-1500 (1 / h), the pressure is normal pressure, and the carrier gas is about 200 ° C. to 240 ° C. Heat to. The reduction operation of the copper-zinc catalyst requires 130-140 (m ³ ) of hydrogen per catalyst (m ³ ), and the amount of water produced corresponds to about 110 (kg). This changes depending on the copper oxide ratio of the copper-zinc catalyst. However, in the case of a copper zinc catalyst having a copper oxide ratio of about 40%, the above-described hydrogen consumption and generated water can be obtained.

Conventionally, this reduction operation is controlled manually while adjusting the flow rates of nitrogen and hydrogen, which are carrier gases, and the amount of hydrogen consumed is eliminated based on the results of hydrogen concentration analysis at the inlet and outlet of the catalytic reactor. When the balance of hydrogen at the entrance and exit coincided, the end of the reduction was judged.
JP 2006-142224 A

  However, the determination of the end of reduction by analyzing the hydrogen concentration at the inlet / outlet of the reactor requires equipment for analyzing the hydrogen concentration, which increases the cost and increases the consumption of hydrogen until there is no more consumption. Since the amount has to be monitored, there is a problem that it takes time to determine the end of the reduction.

  The present invention has been made in view of this point, and an object of the present invention is to provide a reduction processing apparatus that can perform a reduction end determination at a low cost and in a short time.

  The reduction processing apparatus of the present invention includes a catalytic reactor filled with a known amount of catalyst, a cooler that cools a processing gas of the catalytic reactor and performs gas-liquid separation, and starts reduction processing of the catalyst. And a controller for determining the end of reduction in the catalytic reactor based on the amount of water produced by gas-liquid separation in the cooler.

  According to this configuration, since the end of reduction is determined based on the amount of product water generated in gas-liquid separation, the end point of reduction can be accurately obtained without analyzing the hydrogen concentration at the reactor inlet / outlet. The determination can be performed at a low cost and in a short time.

  Moreover, the present invention is characterized in that, in the above reduction treatment apparatus, the control unit determines the end of the reduction based on the amount of generated water at the end of reduction determined from the amount of catalyst charged in the catalytic reactor.

  With this configuration, the amount of generated water at the end of reduction can be calculated in advance from the amount of catalyst charged in the catalytic reactor, so that the amount of generated water can be used as a criterion for determining the end of reduction without analyzing the hydrogen concentration at the inlet / outlet of the reactor. Thus, the end point of reduction can be accurately obtained.

  Further, the present invention provides the above-described reduction treatment apparatus, wherein the controller raises the concentration of the reducing gas within a range not exceeding the upper temperature limit after the reduction end determination based on the amount of generated water, and is provided in the catalytic reactor. The reduction operation is completed after confirming that no abnormal exothermic reaction has occurred from the detection result of the temperature sensor.

  With this configuration, the control unit determines the end of reduction from the amount of generated water and determines whether there is an abnormal exothermic reaction under temperature control after the end of reduction determination, so that complicated temperature management can be reduced and process management of the entire reduction operation can be performed. Can be easy.

  According to the present invention, the product water after gas-liquid separation is weighed and the end of reduction is determined based on the measured amount of product water. Therefore, the end of reduction can be determined at low cost and in a short time.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.
FIG. 1 is a schematic configuration diagram of a reduction processing apparatus according to an embodiment of the present invention.
In the reduction treatment apparatus of the present embodiment, a nitrogen control valve 1 for adjusting the inflow amount of nitrogen (carrier gas) by manual operation is disposed near the inlet of the nitrogen pipe L1. A hydrogen control valve 2 for manually adjusting the inflow amount of hydrogen (reducing gas) is disposed near the inlet of the hydrogen pipe L2. A nitrogen pressure gauge 4 is arranged in the nitrogen pipe L1 on the downstream side of the nitrogen control valve 1 to measure the pressure in the pipe due to the inflow of nitrogen. Further, a hydrogen pressure gauge 5 is provided in the hydrogen pipe L2 on the downstream side of the hydrogen regulating valve 2, and the pressure in the pipe due to the inflow of hydrogen is measured. A nitrogen shut-off valve 7 composed of an electromagnetic valve is disposed in the nitrogen pipe L1 on the downstream side of the nitrogen pressure gauge 4 so that the inflow of nitrogen to the downstream side can be blocked. The nitrogen shut-off valve 7 is controlled to open and close by the control device 24. The hydrogen pipe L2 on the downstream side of the hydrogen pressure gauge 5 is provided with a hydrogen cutoff valve 8 constituted by an electromagnetic valve so that the inflow of hydrogen to the downstream side can be blocked. The hydrogen shut-off valve 8 is controlled to open and close by the control device 24. Further, a nitrogen flow meter 10 is disposed in the nitrogen pipe L1 on the downstream side of the nitrogen cutoff valve 7, so that the nitrogen passing through the nitrogen cutoff valve 7 can be adjusted to a predetermined flow rate. A hydrogen flow meter 11 is disposed in the hydrogen pipe L2 on the downstream side of the hydrogen shut-off valve 8 so that the hydrogen passing through the hydrogen shut-off valve 8 can be adjusted to a predetermined flow rate. The ends of the nitrogen pipe L1 and the hydrogen pipe L2 are connected to a supply pipe L3, and are connected so as to supply a mixed gas of nitrogen and hydrogen to the heater 13. The heater 13 heats the nitrogen that has passed through the nitrogen flow meter 10 and the hydrogen that has passed through the hydrogen flow meter 11, and the amount of heating is adjusted by the control device 24. A catalytic reactor 14 is disposed on the downstream side of the heater 13.

  The catalytic reactor 14 is filled with a CO conversion catalyst 15 of a copper-zinc catalyst, and the CO conversion catalyst 15 is reduced with a mixed gas of nitrogen and hydrogen. By introducing a mixed gas of nitrogen and hydrogen into the catalytic reactor 14, the reaction of the above-described formula (1) is performed in the CO conversion catalyst 15, and the copper oxide is reduced to metallic copper.

  A temperature detector 16 for measuring the temperature of the CO shift catalyst 15 is disposed in the catalyst reactor 14. The temperature detector 16 has three thermocouples 16A to 16C. The thermocouple 16A is positioned near the catalyst layer inlet and detects the temperature of the CO shift catalyst 15 near the inlet of the catalyst reactor 14. The thermocouple 16B is located near the middle of the catalyst layer and detects the temperature of the CO shift catalyst 15 near the middle of the catalyst reactor. The thermocouple 16C is located near the catalyst layer outlet and detects the temperature of the CO shift catalyst 15 near the outlet of the catalytic reactor 14. The temperatures detected by the thermocouples 16 </ b> A to 16 </ b> C are taken into the control device 24 and used for temperature management in the catalytic reactor 14.

  A cooler 17 is disposed on the downstream side of the catalyst reactor 14. The cooler 17 cools the process gas discharged from the catalyst reactor 14 and performs gas-liquid separation. The gas that has been gas-liquid separated and discharged by the cooler 17 is returned to the heater 13 via the supply pipe L3, and the water separated from the gas-liquid is collected in the produced water storage tank 22 as produced water. External circulating water is passed through the cooler 17 and is circulated by the pump 18 while being cooled by the cooler 19. A water level meter 20 is disposed in the cooler 17. The water level level 20 detects the water level of the generated water stored in the cooler 17. The detection signal of the water level meter 20 is taken into the control device 24. The amount of produced water is determined by the amount of catalyst charged in the catalytic reactor 14. Therefore, since the amount of generated water at the end of the reduction can be known by calculation, the water level meter 20 can be arbitrarily set in advance according to the height of the liquid level where the generated water accumulates from the volume of the cooler 17. .

  Between the cooler 17 and the generated water storage tank 22, a shut-off valve 21 configured by an electromagnetic valve and controlled to be opened and closed by a control device 24 is disposed. A balance 23 for measuring the amount of generated water discharged to the generated water storage tank 22 is installed. The measurement value of the generated water by the balance 23 is taken into the control device 24.

  The control device 24 is mainly configured by a computer, and further, a driver for driving the nitrogen cutoff valve 7, the hydrogen cutoff valve 8 and the cutoff valve 21, a driver for driving the heater 13, a microcomputer, a temperature detector 16, and a water level. An interface (not shown) for connecting the level meter 20 and the balance 23 is provided. The control device 24 adjusts the amount of heating in the heater 13 based on information from the temperature detector 16 and opens and closes the nitrogen cutoff valve 7 and the hydrogen cutoff valve 8. Further, the control device 24 opens and closes the shut-off valve 21 based on information from the water level meter 20 and takes in information from the balance 23.

Next, the operation of the reduction processing apparatus according to the present embodiment configured as described above will be described.
First, after the pressure of the nitrogen is adjusted by the nitrogen control valve 1, the nitrogen flows into the nitrogen flow meter 10 through the nitrogen cutoff valve 7, is adjusted to a predetermined flow rate by the nitrogen flow meter 10, and flows into the heater 13. Nitrogen flowing into the heater 13 is preheated by the heater 11 and is heated to about 200 ° C., and then flows into the catalytic reactor 14 to raise the temperature of the CO shift catalyst 15. The temperature in the catalyst reactor 14 is detected by the thermocouples 16 </ b> A to 16 </ b> C of the temperature detector 16 and is taken into the control device 24. The gas discharged from the catalytic reactor 14 enters the cooler 17 and returns to the heater 13 through the cooler 17.

  When nitrogen is supplied and circulated and the CO conversion catalyst 15 is heated to a predetermined temperature of 200 ° C., the control device 24 opens the hydrogen cutoff valve 8. When the hydrogen shut-off valve 8 is opened, hydrogen flows into the hydrogen flow meter 11 and is adjusted to a predetermined flow rate. At this time, the hydrogen flow meter 11 normally adjusts the hydrogen concentration to about 1 mol% to 2 mol% and starts the supply to the downstream side. When the temperature of the CO conversion catalyst 15 exceeds the preset upper limit due to the supply of hydrogen, the control device 24 throttles the hydrogen cutoff valve 8 to reduce the flow rate of hydrogen or opens the nitrogen cutoff valve 7. Control the excessive temperature rise by increasing the flow rate of nitrogen.

  When the mixed gas of hydrogen and nitrogen flows into the CO conversion catalyst 15, copper oxide is reduced to metallic copper by hydrogen by the reaction of the above-described formula (1). At the same time, water is generated. Since the water generated at this time has a high gas temperature, it is introduced into the cooler 17 in the state of water vapor, cooled here, and recovered as generated water. Then, as the reduction progresses and when the reduction is about to end, the water level accumulated in the cooler 17 is detected by the water level meter 20. When the generated water is detected by the water level meter 20, the control device 24 opens the shut-off valve 21 and discharges the generated water accumulated in the cooler 17 to the generated water storage tank 22. The discharge amount of the generated water is measured by a balance 23. The discharged generated water amount is taken into the control device 24. When the control device 24 fetches the measurement result from the balance 23, the control device 24 determines the measurement result and determines the end of the reduction operation.

  After determining the end of the reduction, the control device 24 opens the hydrogen shutoff valve 8 and increases the hydrogen supply amount so that the upper limit of the hydrogen concentration is 50 mol%, and determines that no abnormal exothermic reaction has occurred. The reduction operation is completed when it can be determined from the measurement result of the measuring device 16, and the hydrogen cutoff valve 8 is closed to make the hydrogen flow rate zero. Further, the nitrogen shutoff valve 7 is throttled to reduce the flow rate of nitrogen and the heat source of the heater 13 is turned off, so that the temperature of the CO conversion catalyst 15 is lowered and the temperature is lowered to room temperature.

  By the above procedure, the amount of produced water is calculated in advance from the catalyst filling volume required for reduction, and the reduction operation can be automatically completed by setting the water level meter 20 at an arbitrary position. it can.

  As described above, according to the reduction treatment apparatus of the present embodiment, the produced gas obtained by performing the gas-liquid separation by cooling the treatment gas from the catalyst reactor 14 is measured, and the reduction is completed with the amount of produced water. Since the determination is performed, the end of the reduction can be determined at a low cost and in a short time.

  In the above embodiment, the generated water discharge is measured by the balance 23 and taken into the control device 24. However, it is directly measured by other measuring means such as a flow meter and sent to the control device 24 in real time. You may make it input.

It is a schematic structure figure showing a reduction processing device concerning an embodiment of the invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Nitrogen control valve, 2 ... Hydrogen control valve, 4 ... Nitrogen pressure gauge, 5 ... Hydrogen pressure gauge, 7 ... Nitrogen shut-off valve, 8 ... Hydrogen shut-off valve, 10 ... Nitrogen flow meter, 11 ... Hydrogen flow meter, 13 ... Heater, 14 ... reactor, 15 ... CO shift catalyst, 16 ... temperature detector, 16A-16C ... thermocouple, 17 ... cooler, 18 ... cooling water circulation pump, 19 ... cooler, 20 ... water level meter, 21 ... Shut-off valve, 22 ... generated water storage tank, 23 ... balance, 24 ... control device

Claims (3)

A catalytic reactor filled with a known amount of catalyst;
A cooler for performing gas-liquid separation by cooling the processing gas of the catalytic reactor;
And a controller that determines the end of reduction in the catalytic reactor based on the amount of water produced by gas-liquid separation in the cooler after starting the reduction treatment of the catalyst. Reduction processing device.   The reduction processing apparatus according to claim 1, wherein the control unit determines the end of the reduction based on the amount of generated water at the end of reduction determined from the amount of catalyst charged in the catalytic reactor.   After the reduction end determination based on the amount of generated water, the control unit increases the concentration of the reducing gas within a range not exceeding the upper temperature limit, and an abnormal exothermic reaction is detected from the detection result of the temperature sensor provided in the catalytic reactor. 3. The reduction processing apparatus according to claim 1, wherein the reduction operation is completed after confirming that no occurrence has occurred.

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