JP4199593B2 - Pure hydrogen production equipment - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
TECHNICAL FIELD The present invention relates to an apparatus for producing pure hydrogen gas by purifying a hydrogen-rich reformed gas obtained by reforming a hydrogen atom-containing fuel such as hydrocarbon with a PSA apparatus, and in particular, suppressing carbon dioxide emission. In addition, the present invention relates to a pure hydrogen production apparatus that can be quickly started up with almost no impurities such as carbon monoxide, unburned hydrocarbons, and NOx.
[0002]
[Prior art]
In a polymer electrolyte membrane fuel cell configured by stacking a plurality of cells formed by sandwiching a polymer electrolyte membrane between a fuel electrode (anode) and an oxygen electrode (cathode) from both sides, hydrogen is used as a fuel in the fuel electrode. Is supplied, air is supplied to the oxygen electrode as an oxidant, hydrogen ions generated by a catalytic reaction at the fuel electrode pass through the solid polymer electrolyte membrane to the oxygen electrode, and electrochemical reaction with oxygen at the oxygen electrode To generate electricity. There is known a fuel cell system that generates hydrogen gas supplied as fuel to such a fuel cell by reforming liquid fuel such as hydrocarbon (methanol, gasoline, etc.) or gaseous fuel (methane, ethane, etc.). Yes.
[0003]
For example, a hydrogen production apparatus disclosed in Japanese Patent Laid-Open No. 8-225302 (Patent Document 1) includes a desulfurization apparatus, a high temperature reformer, a high temperature shift apparatus, and a PSA (Pressure Swing Adsorption) apparatus. Among these, the PSA apparatus has one or more adsorption towers filled with an adsorbent that selectively adsorbs components other than hydrogen under high pressure and desorbs under reduced pressure. Each adsorption tower is configured to cyclically perform an operation consisting of adsorption-desorption-substitution-pressure increase so that hydrogen is taken out and other components are discharged as purge gas. Carbon monoxide is a component that is difficult to adsorb in the mixed gas in steam reforming. Therefore, in order to construct the PSA apparatus economically and compactly, it is necessary to keep the concentration of carbon monoxide in the mixed gas entering the PSA apparatus as small as possible. For this purpose, a CO denaturing device is placed upstream of the PSA unit, and a CO denaturing reaction (CO + H ₂ O → H ₂ + CO ₂ ) Reduces the CO concentration and increases the hydrogen concentration as much as possible.
[0004]
However, in a system in which pure hydrogen gas is separated from a hydrogen rich gas obtained by reforming hydrocarbon fuel by a PSA device and supplied to the fuel cell, the reforming system that is the source of the reformed rich gas with respect to power load fluctuations. It is difficult to load hydrogen into the fuel cell because the load fluctuation cannot be followed and hydrogen is responsive to the load fluctuation.
[0005]
On the other hand, at the time of starting the fuel cell system, as an operation for raising the temperature of the reforming catalyst of the reformer to a predetermined activation temperature, for example, starting fuel such as methanol is burned in the starting combustor and the obtained combustion gas is used. A method of heating a reformer [JP 2000-723163 (Patent Document 2)] is known.
[0006]
As another start-up operation of the fuel cell system, for example, air and a fuel such as methanol are supplied to a catalytic combustor disposed upstream of the reformer, and after the catalyst is activated by a burner, methanol and air are supplied. A method of supplying a reforming raw material gas obtained by directly charging, then supplying and evaporating an excessive amount of liquid fuel, and mixing water vapor to a reformer [Japanese Patent Laid-Open No. 2000-191304 (Patent Document 3) ]] Is also known.
[0007]
However, in any of the above systems, fuel such as methanol burns with catalyst or burner, so CO 2 ₂ In addition, there are also emissions of unburned fuel and impurity gases such as CO, which are undesirable in the environment. In addition, since the time required to raise the temperature of the reformer and the evaporator by catalytic combustion of fuel such as methanol is relatively long, there is also a problem that the startup time of the apparatus becomes long.
[0008]
Japanese Patent Application Laid-Open No. 2002-20102 (Patent Document 4) discloses a desulfurization section that removes sulfur content of a raw material hydrocarbon, and a hydrogen-containing gas obtained by steam reforming by adding steam to the raw material hydrocarbon desulfurized in the desulfurization section. A gas reforming section for converting carbon monoxide and steam in the hydrogen-containing gas into carbon dioxide and hydrogen, and a hydrogen-containing gas that has been gas-transformed in the gas conversion section into high-purity hydrogen. In the start-up method of the hydrogen production apparatus comprising the PSA unit to be purified, and the catalytic combustion unit that heats the steam reforming unit by causing a combustion reaction between the hydrogen-containing combustible gas and oxygen in the air, the catalytic combustion When the temperature of the steam reforming part reaches the start temperature of steam reforming, the temperature of the steam reforming part is raised by supplying a high-purity hydrogen and air to the part to cause a catalytic combustion reaction. Open the supply of water vapor and the above raw material hydrocarbons A starting method of a hydrogen production apparatus is disclosed. High purity hydrogen is supplied to the catalytic combustion section from a hydrogen storage tank connected to the PSA section.
[0009]
In this hydrogen production apparatus start-up method, the exhaust gas is clean because the catalytic combustion section is heated by the catalytic combustion reaction of high purity hydrogen obtained from the PSA section. However, it does not mention the use of off-gas from the PSA department.
[0010]
On the other hand, the present applicant has disclosed an apparatus for reforming a fuel gas containing hydrogen atoms into a hydrogen-rich gas of a reforming catalyst, and a plurality of adsorption towers that adsorb impurity gas in the reformed gas and separate pure hydrogen gas. A pressure swing adsorption device comprising: a reformed gas supply means that pressurizes the reformed gas and supplies the reformed gas to the adsorption tower; and an offgas tank that stores offgas formed by desorbing the impurity gas adsorbed on the adsorption tower And a pure hydrogen production apparatus comprising: a catalytic combustor capable of combusting the off gas supplied from the off gas tank; and a means for supplying fuel capable of being combusted by a catalyst to the catalytic combustor. At the start of the manufacturing apparatus, the offgas stored in the offgas tank is supplied to the catalytic combustor, the reformer is heated by the combustion heat of the offgas in the catalytic combustor, and the catalytic converter is heated. When the combustion catalyst of the combustor reaches a predetermined active state, the supply of the off gas to the catalytic combustor is stopped, the fuel is supplied to the catalytic combustor by the fuel supply means, and the reformer Has previously proposed a pure hydrogen production apparatus characterized in that the supply of the fuel to the catalytic combustor is stopped when a predetermined operation start state is reached (Japanese Patent Application No. 2003-090573).
[0011]
The above-mentioned system that heats the combustion catalyst to a predetermined active state by off-gas at the start of the fuel cell system has an advantage of effectively using off-gas. However, when off-gas is burned in the catalytic combustor, carbon dioxide is contained in the exhaust gas. In addition to being included, unburned fuel, carbon monoxide, NOx, etc. are also included, and there is a problem that the cleanliness of the power generation system is somewhat lowered.
[0012]
[Patent Document 1]
JP-A-8-225302
[Patent Document 2]
JP 2000-723163 A
[Patent Document 3]
JP 2000-191304 A
[Patent Document 4]
JP 2002-20102 A
[0013]
[Problems to be solved by the invention]
Therefore, the object of the present invention is to reduce the size of the entire apparatus by utilizing the purification of the reformed gas by the PSA apparatus, and use the off-gas and / or residual gas of the PSA apparatus together with the pure hydrogen gas obtained by the PSA apparatus. By doing so, it is to provide a pure hydrogen production apparatus that can be started quickly and efficiently.
[0014]
[Means for Solving the Problems]
That is, the pure hydrogen production apparatus of the present invention purifies a hydrogen-containing reformed gas obtained by reforming a fuel containing hydrogen atoms by a pressure swing adsorption method to produce pure hydrogen, and (a) a combustion catalyst (B) a reformer having a reforming catalyst connected downstream of the evaporator and generating a hydrogen-rich reformed gas from water vapor and fuel generated by the evaporator. A pressure swing adsorption device connected to the downstream of the reformer and purifying the reformed gas to obtain pure hydrogen gas, and (d) a pulsation obtained from the pressure swing adsorption device. A pulsation mitigating hydrogen tank for storing pure hydrogen gas, and (e) an offgas tank for storing offgas discharged from the pressure swing adsorption device, wherein the pulsation mitigating hydrogen tank and the offgas tank are respectively the catalytic combustor. And before Connected to a reformer, and when the pure hydrogen production apparatus is started up, the pure hydrogen gas in the pulsation mitigating hydrogen tank and the offgas in the offgas tank are appropriately switched and fed to the catalytic combustor and the reformer. The catalyst is combusted to raise the temperature of the catalyst combustor, the evaporator and the reformer.
[0015]
The switching between the pure hydrogen gas and the off gas is preferably determined based on the residual pressures of the pulsation mitigating hydrogen tank and the off gas tank, respectively.
[0016]
In a preferred embodiment of the present invention, the pressure swing adsorption device is also connected to the catalytic combustor and the reformer. In this case, when the pure hydrogen production apparatus is started, the residual gas of the pressure swing adsorption apparatus, the pure hydrogen gas of the pulsation mitigating hydrogen tank, and the off gas of the offgas tank are appropriately switched to the catalytic combustor and the reformer. The catalyst is combusted and fed to raise the temperature of the catalyst combustor and the reformer. The switching of the pure hydrogen gas, the off gas, and the residual gas is preferably determined based on the residual pressures of the pulsation mitigating hydrogen tank, the off gas tank, and the pressure swing adsorption device, respectively.
[0017]
It is preferable that pure hydrogen gas in the pulsation mitigating hydrogen tank is first supplied to the catalytic combustor and the reformer.
[0018]
A cooler and a steam / water separator are provided between the reformer and the pressure swing adsorption device, and it is preferable that water vapor is liquefied and separated from the reformed gas discharged from the reformer.
[0019]
It is preferable that a solid polymer electrolyte fuel cell, a hydrogen storage device, and a hydrogen dispenser are connected to the pulsation mitigating hydrogen tank.
[0020]
A fuel combustion burner is connected to the evaporator and the reformer, and a total heat quantity of residual gas in the pressure swing adsorption device, off-gas in the off-gas tank, and pure hydrogen gas in the pulsation mitigating hydrogen tank is When the amount of heat required to heat the evaporator and the reformer to a predetermined temperature is not reached, fuel is burned by the burner and the combustion gas is sent to the evaporator and the reformer. preferable.
[0021]
DETAILED DESCRIPTION OF THE INVENTION
[1] First embodiment
(A) Structure of pure hydrogen production equipment
FIG. 1 schematically shows the overall configuration of a pure hydrogen production apparatus according to a first embodiment of the present invention. This pure hydrogen production apparatus includes an evaporator 1 for evaporating water and fuel, a reformer 3 connected to the evaporator 1 through a heat exchange unit 2, a cooler 4, a steam separator 5 and a compression. A PSA device 7 connected to the reformer 3 via a machine 6, a pulsation mitigating hydrogen tank 8 for storing pure hydrogen gas purified by the PSA device 7, and an off-gas after separation of the pure hydrogen gas by the PSA device 7 , A solid polymer electrolyte fuel cell (PEFC) 10 connected to the pulsation reducing hydrogen tank 8 via the flow rate adjusting valve V1, a pulsation reducing hydrogen tank 8 to the flow rate adjusting valve V2 and the compressor 11 And a hydrogen dispenser 13 connected to the high-pressure hydrogen tank 12.
[0022]
The evaporator 1 has a built-in catalytic combustor 15 for heating it. The catalytic combustor 15 contains, for example, a Pt-based or Pd-based catalyst as a combustion catalyst. The pulsation mitigating hydrogen tank 8 and the off-gas tank 9 are connected to the starting gas line TL via the shut-off valves V3 and V4, respectively. The starting gas line TL is the injection means (flow control means) INJ-1 and INJ-, respectively. 2 is connected to the reformer 3 and the catalytic combustor 15. In this example, fuel combustion burners 18 and 19 are connected to the catalytic combustor 15 and the reformer 3, respectively, and shut-off valves V5 and V6 are provided in the fuel supply lines of the burners 18 and 19, respectively.
[0023]
The reformer 3 has a reforming catalyst such as a Rh-based or a Ru-based, and partially oxidizes the fuel with the reforming air by the action of the reforming catalyst and reforms the fuel with steam to generate hydrogen. Produces rich reformed gas. Although this reforming reaction is an endothermic reaction, the amount of heat necessary for this is replenished by an oxidation reaction. For example, when methane is used as a fuel, CH2 is generated by methane, oxygen in the air, and water vapor. _Four + 2O ₂ → CO ₂ + 2H ₂ O (exothermic reaction) and CH _Four + 2H ₂ O → CO ₂ + 4H ₂ (Endothermic reaction) occurs simultaneously. Such an autothermal (ATR) type reformer 3 does not require an external heating means, and thus has a simple configuration and a short temperature increase (warming-up) time.
[0024]
The PSA device 7 separates only hydrogen gas from the hydrogen-rich reformed gas generated by the reformer 3, and has a structure shown in FIG. 2, for example. The PSA device 7 includes first to third adsorption towers 71a, 71b, 71c, first to third three-way switching valves 72a, 72b, 72c, and first to third pressure equalization control valves 73a, 73b. 73c. Each adsorption tower 71a, 71b, 71c is filled with an adsorbent such as activated carbon or zeolite.
[0025]
The compressor 6 is connected to the adsorption towers 71a, 71b, 71c via the three-way switching valves 72a, 72b, 72c, and the reformed gas is pressurized by the compressor 6 and is applied to the adsorption towers 71a, 71b. , 71c. Each adsorption tower 71a, 71b, 71c adsorbs the impurity gas such as carbon monoxide and nitrogen contained in the reformed gas by the adsorbent, and the pure hydrogen gas that has not been adsorbed is connected to each adsorption tower 71a, 71b, 71c. It flows to the pulsation mitigating hydrogen tank 8. Any one of the first to third switching control valves 72a, 72b, 72c is a flow direction F from the compressor 6 toward the adsorption towers 71a, 71b, 71c. _IN Is set to
[0026]
Each adsorption tower 71a, 71b, 71c is connected to the off-gas tank 9 via each switching control valve 72a, 72b, 72c. When the pure hydrogen gas discharged from any of the first to third adsorption towers 71a, 71b, 71c flows through each adsorption tower 71a, 71b, 71c as a cleaning gas, the adsorption in each adsorption tower 71a, 71b, 71c Impurity gases such as carbon monoxide and nitrogen adsorbed by the agent are desorbed and discharged to the off-gas tank 9, and the interior of each adsorption tower 71a, 71b, 71c is cleaned. Any one of the first to third switching control valves 72a, 72b, 72c has a flow direction F from each adsorption tower 71a, 71b, 71c toward the off-gas tank 9. _OUT Is set to
[0027]
Each adsorption tower 71a, 71b, 71c is connected to a pressure equalization control flow path 76 via a three-way switching valve 73a, 73b, 73c, and each pressure equalization control valve 73a, 73b, 73c is connected to each adsorption tower 71a, 71b, It is possible to switch the flow direction OUT from 71c to the pressure equalization control flow path 76 or the flow direction IN from the pressure equalization control flow path 76 to each adsorption tower 71a, 71b, 71c.
[0028]
In the process of pressure equalization and pressure equalization, one of the first to third pressure equalization control valves 73a, 73b, 73c is closed, and the other is set to the flow direction OUT toward the pressure equalization control flow path 76. If the last one is set in the flow direction 1N toward the adsorption towers 71a, 71b, 71c, the internal pressures of any two of the first to third adsorption towers 71a, 71b, 71c are the same.
[0029]
By controlling the switching of the flow direction by the switching control valves 72a, 72b, 72c and the pressure equalization control valves 73a, 73b, 73c, as shown in FIG. 3, the adsorption, pressure equalization, pressure reduction, washing, pressure equalization are sequentially performed. Then, a series of processes consisting of pressurization is repeated, and pure hydrogen gas is continuously separated from the reformed gas.
[0030]
PSA device controlled by first to third adsorption towers 71a, 71b, 71c, first to third switching control valves 72a, 72b, 72c, and first to third pressure equalization control valves 73a, 73b, 73c The operation of No. 7 is as shown in FIG.
[0031]
Other devices than the above may be the same as the conventional ones unless otherwise specified.
[0032]
(B) Operation of pure hydrogen production equipment
(1) Starting the reforming system
FIG. 4 shows an example of starting the reforming system (including the evaporator 1 and the reformer 3). In FIG. 4, the temperature T of the combustion catalyst of the catalytic combustor 15 ₁ And the temperature T of the reforming catalyst of the reformer 3 ₂ Only the process of using the pure hydrogen gas in the pulsation mitigating hydrogen tank 8 to raise the pressure is shown. Of course, in the present invention, the off gas in the off gas tank 9 is also used. Furthermore, the residual gas (mainly hydrogen gas) of the PSA device 7 can be used.
[0033]
When off gas and residual gas are used in addition to pure hydrogen gas, switching between these gases is determined based on the residual pressures of the PSA device 7, the pulsation mitigating hydrogen tank 8, and the off gas tank 7. In this case, the order in which pure hydrogen gas, off-gas, and residual gas are supplied to the catalytic combustor 15 and the reformer 3 can be set as appropriate.
[0034]
The flow chart of FIG. 4 shows the temperature rise of the catalytic combustor 15 first for convenience, but this does not mean that the temperature rise of the catalytic combustor 15 should be performed first. In addition, the temperature of the reformer 3 can be increased at the same time. However, in any case, it is preferable to first supply the pure hydrogen gas from the pulsation mitigating hydrogen tank 8 to the catalytic combustor 15 and the reformer 3.
[0035]
To start the reforming system according to the procedure of the flowchart of FIG. ₁ And the temperature T of the reforming catalyst of the reformer 3 ₂ Is detected (step A2). Next, the internal pressure P of the pulsation reducing hydrogen tank 8 _Three Is higher than the rating (process A3), and if it is higher than the rating, the internal pressure P of the pulsation reducing hydrogen tank 8 _Three And combustion catalyst temperature T ₁ Thus, the injection amount of hydrogen supplied to the catalytic combustor 15 is determined (step A4). Further, starting air is injected into the catalytic combustor 15 (step A5), and hydrogen is injected from the pulsation mitigating hydrogen tank 8 into the catalytic combustor 15 to raise the temperature of the combustion catalyst (step A6).
[0036]
Combustion catalyst temperature T ₁ Is equal to or higher than a predetermined temperature Tc (eg, 540 ° C.) (step A7). If the temperature is lower than the predetermined temperature Tc, step A6 is repeated. If the temperature is higher than the predetermined temperature Tc, the internal pressure P of the pulsation reducing hydrogen tank 8 _Three And reforming catalyst temperature T ₂ Thus, the injection amount of hydrogen to the reforming catalyst is determined (step A8), and start-up air to the reforming catalyst is injected (step A9).
[0037]
Hydrogen is injected into the reforming catalyst from the pulsation mitigating hydrogen tank 8 to raise the temperature of the reforming catalyst (step A10), and the reforming catalyst temperature T ₂ Is equal to or higher than a predetermined temperature Tc (eg, 540 ° C.) (step A11). If the temperature is lower than the predetermined temperature Tc, the process A10 is repeated. When the temperature is equal to or higher than the predetermined temperature Tc, the temperature raising of the reformer is completed.
[0038]
In step A3, the internal pressure P of the pulsation reducing hydrogen tank 8 _Three Is determined to be below the rating, the combustion catalyst temperature T ₁ And reforming catalyst temperature T ₂ Thus, the flow rate of the fuel supplied to each fuel combustion burner 18, 19 is determined (step A4 '). Operate burner 18 (process A5 '), combustion catalyst temperature T ₁ Is equal to or higher than a predetermined temperature Tc (eg, 540 ° C.) (step A6 ′). If the temperature is lower than the predetermined temperature Tc, step A5 ′ is repeated. When the temperature is equal to or higher than the predetermined temperature Tc, the burner 19 is similarly operated (step A7 ′), and the reforming catalyst temperature T ₂ Is equal to or higher than a predetermined temperature Tc (for example, 540 ° C.) (step A8 ′). If the temperature is lower than the predetermined temperature Tc, the process A7 ′ is repeated. When the temperature is equal to or higher than the predetermined temperature Tc, the temperature raising of the reformer is completed.
[0039]
In step A4 ′ to step A8 ′, the evaporator 1 and the reformer 3 are heated by the combustion gas from the fuel combustion burners 18 and 19, but of course, the temperature is increased using off-gas and / or residual gas. You can also. The extent to which the evaporator 1 and the reformer 3 are heated by the combustion gas of the burners 18 and 19 is determined based on the residual pressures of the PSA device 7, the pulsation mitigating hydrogen tank 8 and the offgas tank 7.
[0040]
(2) Determination of fuel input
As shown in FIG. 5, after the temperature raising of the reforming system is completed, the internal pressure P of the pulsation alleviating hydrogen tank 8 _Three And the internal pressure P of the high-pressure hydrogen tank 12 _Four Thus, the reforming load (fuel supply amount, etc.) is determined according to the table (step B4). The reformer 3 is operated with the reforming load set in the process B4 (process B5), and the power generation load is monitored to determine whether or not it is below the rating (process B6). If the power generation load exceeds the rating, process B5 is repeated, and if it is less than the rating, the internal pressure P of the pulsation reducing hydrogen tank 8 _Three It is determined whether or not is over the rating (step B7). P _Three If B is less than the rating, repeat step B5. If the rating is greater than the rating, the reforming load is lowered step by step in accordance with the reforming load table, and finally reformed under the rated conditions. The vessel 3 is operated (step B8).
[0041]
(3) Tracking power generation load
As shown in FIG. 6, after the reforming system has been heated, the amount of power generated by the PEFC is monitored (step C2), and the flow rate adjusting valve V provided upstream of the PEFC according to the amount of power generated. ₁ Is feedback controlled (step C3). As a result, an amount of pure hydrogen gas corresponding to the power generation load is supplied to the PEFC.
[0042]
(4) Production of high-pressure hydrogen
Since the load at home varies with time, the PEFC needs to follow the load (power generation load) to generate power. In other words, hydrogen gas corresponding to the fluctuating power generation load must be supplied to the PEFC. Since the reformer 3 cannot follow this fluctuation in the power generation load, as shown in FIG. 7, during the rated operation of the reformer 3, the pulsation mitigating hydrogen tank 8 follows the power generation load and the required amount of hydrogen for the PEFC. Gas is supplied (process D2). Next, it is determined whether or not the power generation load is equal to or less than a predetermined ratio (for example, 70%) of the rating (step D3). When the ratio is less than the predetermined ratio, the internal pressure P of the pulsation reducing hydrogen tank 8 _Three Determines whether or not is equal to or higher than a predetermined value (eg, 500 kPa) (process D4). _Three When is less than the predetermined value, the operation of the power generation system is continued.
[0043]
P _Three Is higher than the specified value, the internal pressure P of the high-pressure hydrogen tank 12 _Four Is less than or equal to a predetermined value (for example, 30 MPa) (process D5), P _Four When is over a predetermined value, the operation of the power generation system is continued. Also P _Four Is below the specified value, the power generation load, the internal pressure P of the pulsation mitigating hydrogen tank 8 _Three And the internal pressure P of the high-pressure hydrogen tank 12 _Four Therefore, the flow control valve V provided upstream of the high-pressure hydrogen tank 12 ₂ Is calculated (step D6). The compressor 11 is operated based on the calculated value of the process D6, and the high-pressure hydrogen tank 12 is filled with hydrogen gas (process D7). Internal pressure P of pulsation mitigating hydrogen tank 8 _Three Is the predetermined value P _B (For example, 500 kPa) or the internal pressure P of the high-pressure hydrogen tank 12 _Four Is the predetermined value P _H If it exceeds (for example, 35 MPa) or satisfies any of the conditions, the operation of the compressor 11 for the high-pressure hydrogen tank 12 is stopped (step D8).
[0044]
(5) Determination of fuel flow rate to be input to the reformer during rated operation
As shown in FIG. 8, during the rated operation of the reformer 3, the power generation system is operated following the power generation load (step E2). It is determined whether or not the power generation load is equal to or greater than a predetermined ratio (for example, 70%) of the rating (step E3). If the power generation load is less than the predetermined ratio, the process returns to step E2 to continue the operation of the power generation system. If the power generation load is less than the rated ratio, the internal pressure P of the pulsation reducing hydrogen tank 8 _Three Is determined to be less than or equal to a predetermined value (for example, 500 kPa) (step E4), P _Three When is over a predetermined value, the operation of the power generation system is continued.
[0045]
P _Three Is less than the specified value, the internal pressure P of the pulsation reducing hydrogen tank 8 _Three And the internal pressure P of the high-pressure hydrogen tank 12 _Four Thus, the reforming load is determined (step E5), and the flow rate of the reforming fuel is increased stepwise while interlocking with the PSA device 7 (step E6). It is determined whether or not the power generation load is below the rating (step E7). If the power generation load exceeds the rating, step E6 is repeated. If the power generation load is below the rating, the internal pressure P of the pulsation mitigating hydrogen tank 8 _Three Is the predetermined value P _B It is determined whether or not (for example, 500 kPa) or more (step E8). P _Three Is the predetermined value P _B If less, repeat step E6. Also P _Three Is the predetermined value P _B In the above case, according to the reforming load table, the reforming load is lowered step by step in conjunction with the PSA device 7 and converged to the rated operation (step E9).
[0046]
[2] Second embodiment
(A) Structure of pure hydrogen production equipment
FIG. 9 schematically shows the overall configuration of a pure hydrogen production apparatus according to the second embodiment of the present invention. In addition, the same reference number is attached | subjected to the apparatus same as the apparatus in a 1st Example.
[0047]
A three-way switching valve V between the reformer 3 and the cooler 4 ₇ A three-way selector valve V ₇ Is connected to the circulation line R. Three-way switching valve V between PSA device 7 and pulsation mitigating hydrogen tank 8 ₈ A three-way selector valve V ₈ And the starting gas line TL are connected by a PSA residual gas line Z. An emergency hydrogen tank 20 is provided between the high-pressure hydrogen tank 12 and the starting gas line TL, and a shutoff valve V is provided on both sides of the emergency hydrogen tank 20. ₁₃ , V ₁₄ Is provided. The emergency hydrogen tank 20 is a tank filled with hydrogen as energy necessary for the first start-up when the system is installed. When used for start-up, the emergency hydrogen tank 20 is replenished from the high-pressure hydrogen tank 12 during operation.
[0048]
The cathode of the PEFC 10 is connected to the circulation line R and the catalytic combustor 15. V ₁₅ Is a pressure regulating valve. Also V ₁₅ Also adjust the pressure in the circulation line R with the pressure regulating valve. Since the configuration other than the above is substantially the same as the pure hydrogen production apparatus according to the first embodiment, the description thereof is omitted.
[0049]
(B) Operation of pure hydrogen production equipment
(1) Temperature rise of reforming system
As shown in Fig. 10, the three-way switching valve V ₇ Is connected to the circulation line R (step F2). Combustion catalyst temperature T ₁ And reforming catalyst temperature T ₂ , And the injection amount of the injection means INJ-1 and INJ-2 and the temperature T of the evaporator 1 _Three To combustion catalyst temperature T ₁ And reforming catalyst temperature T ₂ The amount of heat V required to raise the temperature of the reforming system to a predetermined temperature (for example, 550 ° C.) is calculated, and the amount of off-gas heat VC required to raise the temperature of the entire reforming system from the catalyst temperature (for example, 550 ° C.) The flow rates of starting air, heated air and reforming air are calculated (step F3). Furthermore, the internal pressure P of the PSA device 7 ₁ , The internal pressure P of the offgas tank 9 ₂ And the internal pressure P of the pulsation reducing hydrogen tank 8 _Three Detecting the amount of hydrogen P in each tank ₁ Q, P ₂ Q, P _Three Q is calculated (step F4).
[0050]
P ₁ It is determined whether or not the condition of Q <V + VC is satisfied (process F5). If not satisfied, the process proceeds to flow A. If satisfied, P is satisfied. ₂ It is determined whether or not the condition of Q> VC is satisfied (step F6). P ₂ If the condition of Q> VC is not satisfied, go to Step F18 and P ₁ Q + P ₂ Q + P _Three Judge whether the condition of Q> V + VC is satisfied. P ₁ Q + P ₂ Q + P _Three If the condition Q> V + VC is satisfied, P _Three The process proceeds to step F7 for determining whether or not the condition of Q> V is satisfied. Otherwise, the process proceeds to flow B. Also, P in the judgment of process F6 ₂ If the condition Q> VC is satisfied, go to process F7 and P _Three If the condition of Q> V is not satisfied, P ₁ Q + P _Three The process proceeds to Step F19 for determining whether or not the condition of Q> V is satisfied. If not satisfied, the process proceeds to Flow B. In addition, when both the determination of the process F7 and the determination of the process F19 are satisfied, the temperature raising of the reforming system is started (processes F8 and F20, respectively).
[0051]
3-way selector valve V ₈ Is connected to line Z (process F9), and reforming catalyst temperature T ₂ Is set to a target value (for example, 550 ° C.), the residual gas of the PSA device 7 is injected from the injection means INJ-1 to the reformer 3, and the temperature of the reformer 3 is increased (step F10). At that time, start-up air is also supplied to the reformer 3. Further, the pressure of the circulation line R is set to 5 kPa, for example, and the residual gas of the PSA device 7 is injected into the catalytic combustor 15 from the injection means INJ-2, and the combustion catalyst temperature T ₁ For example, the evaporator 1 is heated (step F11).
[0052]
Combustion catalyst temperature T ₁ And reforming catalyst temperature T ₂ Is determined to exceed a predetermined value (for example, 540 ° C.) (step F12). If not, the process returns to step F10, and if it exceeds, the temperature T of the evaporator 1 is exceeded. _Three It is determined whether or not the temperature exceeds a predetermined temperature H ° C. (step F13). The predetermined temperature H ° C. is measured by a temperature sensor installed at a site where it can be determined whether or not the temperature raising of the entire system has been completed. For example, three-way switching valve V ₇ Assume that the temperature of the pipe wall surface is H ° C., and when the temperature reaches 150 ° C. (a safety factor is set for the reformed gas dew point temperature), the temperature rise of the housing is completed. However, the installation location may be any location where the temperature rise of the system can be determined.
[0053]
T _Three When the condition of> H ° C. is satisfied, the temperature raising of the reforming system is completed (step F14), and reforming is started (step F15). If not satisfied, the three-way selector valve V ₈ And shut off the shutoff valve V ₁₂ And the off-gas in the off-gas tank 9 is injected from the injection means INJ-2 to the catalytic combustor 15 to raise the temperature of the combustion catalyst (step F16). Combustion catalyst temperature T ₁ And reforming catalyst temperature T ₂ For example, the evaporator 1 and the reformer 3 are heated from the injection means INJ-1 and INJ-2 (step F17), and the process returns to the step F13.
[0054]
As the process F20 and subsequent steps for starting the temperature raising of the reforming system, first, the three-way switching valve V ₈ Is connected to the PSA residual gas line Z (process F21), and the reforming catalyst temperature T ₂ Is set to, for example, 550 ° C., the residual gas in the PSA device 7 is injected into the reformer 3 from the injection means INJ-1, and the temperature of the reformer 3 is increased (step F22). The pressure Pa of the starting gas line TL is the pressure regulating valve V ₁₅ When the pressure drops to the same pressure as the three-way selector valve V ₈ And shut off the shutoff valve V ₁₁ And the line X of the pulsation reducing hydrogen tank 8 is connected to the starting gas line TL (step F23). Reforming catalyst temperature T ₂ Is set to, for example, 550 ° C., a portion of the pure hydrogen gas in the pulsation mitigating hydrogen tank 8 is injected onto the reforming catalyst from the injection means INJ-1, and the temperature of the reformer 3 is increased (step F24). In addition, the pressure of the circulation line R is, for example, 5 kPa, and the combustion catalyst temperature T ₁ Is set to, for example, 550 ° C., a portion of the pure hydrogen gas in the pulsation mitigating hydrogen tank 8 is injected into the catalytic combustor 15 from the injection means INJ-2, and the evaporator 1 is heated (step F25).
[0055]
Combustion catalyst temperature T ₁ And reforming catalyst temperature T ₂ Is determined to exceed a predetermined value (for example, 540 ° C.) (step F26). If not, the process returns to step F22, and if it exceeds, the process proceeds to flow C.
[0056]
In the flow A shown in FIG. 11, the temperature raising of the reforming system is started. First, three-way selector valve V ₈ Is connected to the PSA residual gas line Z (process F28), and the reforming catalyst temperature T ₂ Is set to 550 ° C., for example, PSA residual gas is supplied from the injection means INJ-1 to the reformer 3, and reforming air is also supplied to raise the temperature of the reformer 3 (step F29). In addition, the pressure of the circulation line R is, for example, 5 kPa, and the combustion catalyst temperature T ₁ For example, the injection means INJ-2 is operated, the PSA residual gas and the starting air are supplied to the catalyst combustor 15, and the evaporator 1 is heated (step F30). Combustion catalyst temperature T ₁ And reforming catalyst temperature T ₂ For example, it is determined whether or not both are over 540 ° C. (step F31). The combustion catalyst temperature T ₁ And reforming catalyst temperature T ₂ When both are over 540 ° C, the temperature T of the evaporator 1 _Three It is determined whether or not the temperature exceeds a predetermined temperature H ° C. (step F32). Temperature T _Three If the temperature does not exceed H ° C., the process returns to step F30, and if it exceeds, the temperature raising of the reforming system is completed (step F33), and reforming is started (step F34).
[0057]
Flow B shown in FIG. 12 is an emergency sequence. First, the pressure P of the emergency hydrogen tank 20 _Five Calorie of hydrogen stored from V _B Is calculated (step F35). V _B To determine whether V exceeds V (process F36), V _B If is below V, issue a warning and stop activation. Also V _B P if V exceeds V ₁ Q + P ₂ Q + P _Three Q + V _B It is determined whether or not a condition of> V + VC is satisfied (step F37). If this condition is not met, an alarm is issued and the activation is stopped. If it satisfies the condition, the shutoff valve V ₁₃ Is opened and the emergency hydrogen tank 20 is connected to the starting gas line TL and the reforming air is supplied to the reformer 3 (step F38). Reforming catalyst temperature T ₂ Is set to, for example, 550 ° C., hydrogen gas is injected from the injection means INJ-1, and the reformer 3 is heated (step F39). In addition, the pressure of the circulation line R is, for example, 5 kPa, and the combustion catalyst temperature T ₁ For example, the injection means INJ-2 is operated, hydrogen gas is supplied from the emergency hydrogen tank 20 to the catalytic combustor 15, and the evaporator 1 is heated (step F40).
[0058]
Combustion catalyst temperature T ₁ And reforming catalyst temperature T ₂ For example, it is determined whether or not both are over 540 ° C. (step F41). The combustion catalyst temperature T ₁ And reforming catalyst temperature T ₂ When both are over 540 ° C, the temperature T of the evaporator 1 _Three Is determined to be less than a predetermined temperature H ° C. (step F42).
[0059]
Temperature T _Three When is below H ° C, the pressure Pa in the starting gas line TL is ₁₅ When the pressure drops to the same as the adjustment pressure of ₁₃ Is closed and the three-way selector valve V ₈ Is connected to the line Z, and the residual gas of the PSA device 7 is injected from the injection means INJ-2 into the catalytic combustor 15 and the combustion catalyst temperature T ₁ To raise. Further, while continuing to monitor the pressure Pa of the starting gas line TL, it is connected to the starting gas line TL in the order of line Y → line X, and off-gas and pure hydrogen gas are injected into the catalyst combustor 15 in order, and the combustion catalyst Temperature T ₁ Is raised (step F43). Next, returning to step F42, the temperature T of the evaporator 1 is reached. _Three Is determined to be less than a predetermined temperature H ° C. Repeat this cycle until the temperature T _Three When the temperature reaches H ° C. or higher, the temperature raising of the reforming system is completed (step F44), and reforming is started (step F45).
[0060]
In the flow C shown in FIG. 13, the temperature T of the evaporator 1 _Three Is lower than the predetermined temperature H ° C (step F46), and if it is equal to or higher than H ° C, the temperature raising of the reforming system is completed (step F47), and reforming is started (step F48). When the temperature is lower than H ° C, the pressure Pa of the starting gas line TL is ₁₅ When the pressure drops to the same pressure as the three-way selector valve V ₁₁ And shut off the shutoff valve V ₁₂ And the line Y of the off-gas tank 9 is connected to the starting gas line TL (step F49). Combustion catalyst temperature T ₁ And reforming catalyst temperature T ₂ Is set to 550 ° C., for example, off-gas is injected from the injection means INJ-1 and INJ-1 to the catalytic combustor 15 and the reformer 3, respectively, and the evaporator 1 and the reformer 3 are heated (step F50). ).
[0061]
Evaporator 1 temperature T _Three It is determined whether or not the temperature exceeds a predetermined temperature H ° C. (step F51). Temperature T _Three If the temperature does not exceed H ° C., the process returns to step F39, and if it exceeds, the temperature raising of the reforming system is completed (step F52), and reforming is started (step F53).
[0062]
As described above, the first and second embodiments have been described separately, but this is of course not intended to be limited to each operation, and the procedures of the first and second embodiments may be combined as necessary. It should be understood that it can be done.
[0063]
Using the pure hydrogen production apparatus of the second embodiment, the hydrogen gas remaining in the PSA apparatus 7 is supplied to the reforming catalyst in the reformer 3 at room temperature (24 ° C.), and the reforming catalyst temperature T is obtained by catalytic combustion. ₂ Was raised. Next, when the pressure in the circulation line R rises to 5 kPa, hydrogen gas is supplied to the combustion catalyst in the catalytic combustor 15, and the combustion catalyst temperature T ₁ Was raised. When each catalyst temperature reached 540 ° C., off-gas was supplied to the reformer 3 and the catalytic combustor 15 instead of hydrogen gas, and the off-gas was catalytically combusted. Combustion catalyst temperature T at this time ₁ And reforming catalyst temperature T ₂ , And three-way switching valve V ₈ The temperature inside was measured. The results are shown in FIG. The temperature rise of this reforming system is ₈ The temperature was evaluated by the time required for the temperature to reach H ° C (150 ° C). As a result, it was found that this reforming system reached the required temperature in 55 seconds. From this, it can be seen that the startup time of the pure hydrogen production apparatus of the present invention is within 1 minute.
[0064]
FIG. 15 shows the impurity components in the exhaust gas exiting from the catalytic combustor 15 when started in the above procedure. During hydrogen combustion, CO, total hydrocarbon components and N _OX The amount of CO was 0, and after switching to off-gas combustion, a small amount of CO and total hydrocarbon components were slightly discharged. From this result, it was found that the exhaust gas as a whole is very clean when the temperature of the reforming system according to the present invention is increased.
[0065]
【The invention's effect】
Since a high-purity hydrogen is separated from a hydrogen-rich gas obtained by reforming hydrogen atom-containing fuel such as natural gas or LPG using a PSA device, the hydrogen in the pulsation mitigation hydrogen tank connected to the PSA device is used as a fuel cell. The high-pressure hydrogen tank can be filled with high pressure.
[0066]
At startup, the hydrogen gas stored in the pulsation mitigating hydrogen tank and / or the gas (mainly consisting of hydrogen gas) remaining in the PSA unit is supplied to the catalytic combustor and reformer attached to the evaporator, so that the temperature can be quickly reduced. Hydrogen catalytic combustion occurs. Further, by switching from hydrogen gas to off-gas when a predetermined temperature (for example, 540 ° C.) is reached, the off-gas can be effectively used for raising the temperature of the evaporator and reformer. With such a temperature raising system, the temperature rise of the evaporator and the reformer from a low temperature is quick, and not only the startup time of the pure hydrogen production apparatus is short, but also the exhaust gas is relatively clean.
[0067]
In particular, reforming systems used in home refueling systems (HRS) that charge hydrogen to vehicles with pure hydrogen fuel cells (FCV) at home frequently start and stop, so energy for heating that hinders efficiency However, since the start-up device of the present invention is quick to start, it is preferable.
[Brief description of the drawings]
FIG. 1 is a schematic view showing an apparatus for producing pure hydrogen according to an embodiment of the present invention.
FIG. 2 is a block diagram showing a detailed structure of a PSA device.
FIG. 3 is a diagram showing the operation of each adsorption tower in the PSA device.
FIG. 4 is a flowchart for determining the amount of fuel to be charged into a reformer that has been heated.
FIG. 5 is a flowchart for controlling the amount of hydrogen gas input to the solid polymer electrolyte fuel cell according to the amount of power generation.
FIG. 6 is a flowchart showing an example of a temperature raising process of the reforming system.
FIG. 7 is a flowchart showing an example of a high-pressure hydrogen production process.
FIG. 8 is a flowchart for determining the amount of fuel to be charged into the reformer during rated operation.
FIG. 9 is a schematic view showing a pure hydrogen production apparatus according to another embodiment of the present invention;
FIG. 10 is a flowchart showing another example of the temperature raising process of the reforming system.
FIG. 11 is a flowchart showing a part of the reforming system of FIG.
12 is a flowchart showing a part of the reforming system of FIG.
13 is a flowchart showing a part of the reforming system of FIG.
FIG. 14 is a graph showing a temperature rising pattern when hydrogen gas and off-gas are supplied to the reforming catalyst and the combustion catalyst, respectively.
FIG. 15 is a graph showing the impurity concentration in exhaust gas that is emitted when catalytic combustion of hydrogen gas and off-gas fed to the catalytic combustor occurs.
[Explanation of symbols]
1 Evaporator
2 ... Heat exchanger
3 ... ATR reformer
4 ... Cooler
5 ... Steam separator
6 ... Compressor
7 ... PSA equipment
8 ... Pulsation relaxation hydrogen tank
9 ... Off-gas tank
10 ... PEFC
11 ... Compressor
12 ... High pressure hydrogen tank
13 ... Hydrogen dispenser
15 ... Catalyst combustor
20 ... Emergency hydrogen tank
71a, 71b, 71c ・ ・ ・ Adsorption tower
72a, 72b, 72c ・ ・ ・ Three-way selector valve
73a, 73b, 73c ・ ・ ・ equal pressure control valve
74 ・ ・ ・ Hydrogen storage unit

Claims (8)

An apparatus for producing pure hydrogen by purifying a hydrogen-containing reformed gas obtained by reforming a fuel containing hydrogen atoms by a pressure swing adsorption method, and (a) a catalytic combustor having a combustion catalyst is incorporated. An evaporator; and (b) a reformer connected downstream of the evaporator and having a reforming catalyst that generates hydrogen-rich reformed gas from water vapor and fuel generated by the evaporator; and (c) the reformer. A pressure swing adsorption device connected to the downstream of the mass device to obtain the pure hydrogen gas by purifying the reformed gas, and (d) pulsation relaxation for storing the pure hydrogen gas having pulsation obtained from the pressure swing adsorption device A hydrogen tank, and (e) an offgas tank for storing offgas from the pressure swing adsorption device, wherein the pulsation mitigating hydrogen tank and the offgas tank are connected to the catalytic combustor and the reformer, respectively. The net At the time of starting the element production apparatus, the pure hydrogen gas of the pulsation mitigating hydrogen tank and the off gas of the off gas tank are appropriately switched and fed to the catalytic combustor and the reformer to perform catalytic combustion, An apparatus for producing pure hydrogen, wherein the temperature of the evaporator and the reformer is increased. 2. The pure hydrogen production apparatus according to claim 1, wherein switching between the pure hydrogen gas and the off gas is determined based on residual pressures of the pulsation mitigating hydrogen tank and the off gas tank, respectively. 2. The pure hydrogen production apparatus according to claim 1, wherein the pressure swing adsorption device is also connected to the catalytic combustor and the reformer, and a residual gas of the pressure swing adsorption device is activated when the pure hydrogen production device is started. Then, the pure hydrogen gas in the pulsation mitigating hydrogen tank and the off gas in the off gas tank are appropriately switched and supplied to the catalytic combustor and the reformer for catalytic combustion, thereby raising the catalytic combustor and the reformer. A pure hydrogen production apparatus characterized by heating. 4. The pure hydrogen production apparatus according to claim 3, wherein switching of the residual gas, the pure hydrogen gas, and the off gas is determined based on residual pressures of the pressure swing adsorption device, the pulsation relaxation hydrogen tank, and the off gas tank, respectively. Pure hydrogen production equipment characterized by The pure hydrogen production apparatus according to any one of claims 1 to 4, wherein pure hydrogen gas in the pulsation relaxation hydrogen tank is first supplied to the catalytic combustor and the reformer. apparatus. The pure hydrogen production apparatus according to any one of claims 1 to 5, wherein a cooler and a steam separator are provided between the reformer and the pressure swing adsorption device. A pure hydrogen production apparatus characterized in that water vapor is liquefied and separated from the reformed gas. 7. The pure hydrogen production apparatus according to claim 1, wherein a solid polymer electrolyte fuel cell, a hydrogen storage device, and a hydrogen dispenser are connected to the pulsation relaxation hydrogen tank. apparatus. The pure hydrogen production apparatus according to any one of claims 1 to 7, wherein a fuel combustion burner is connected to the evaporator and the reformer, and residual gas in the pressure swing adsorption device, in the off-gas tank When the total amount of heat of off-gas and pure hydrogen gas in the pulsation mitigating hydrogen tank does not reach the amount of heat required to heat the evaporator and the reformer to a predetermined temperature, the burner burns fuel, An apparatus for producing pure hydrogen, wherein combustion gas is supplied to the evaporator and the reformer.

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