| 摘要 |
Two or more methods selected among a steam reforming method, a partial oxidation reforming method, and an autothermal reforming method are defined as i-th reforming method. Functions Fi=fi(P), P=fi−1(Fi), and ηi=gi(P) are obtained in advance. If there is a number i which satisfies FiR≧Fimin, the following process (1) is performed when PD≦P is satisfied, and the following process (2) is performed when PD>PiM is satisfied. In the process (1), if fi(PD)≦FiR is satisfied, Pi*=PD and Fi*=fi(PD), and if fi(PD)>FiR is satisfied, Pi*=(the maximum fi−1(FiR) which is less than PD) and Fi*=FiR. In the process (2), if fi(PiM)≦FiR is satisfied, Pi*=PiM and Fi*=fi(PiM), and if fi(PiM)>FiR is satisfied, Pi*=(the maximum fi−1(FiR)) and Fi*=FiR. If there are a plurality of numbers i which satisfy FiR≧Fimin, PI*, a reforming method, and FI*, which relate to the number i which provides the maximal ηi=gi(Pi*), are adopted. |
| 主权项 |
1. A method of load following operation of a fuel cell system comprising a reformer for reforming a hydrocarbon-based fuel to produce a reformed gas containing hydrogen, said reformer having a reforming catalyst layer, and a high temperature fuel cell for generating electric power using the reformed gas, wherein
at least two reforming methods selected from the group consisting of a steam reforming method, a partial oxidation reforming method, and an autothermal reforming method are determined as i-th reforming methods, where i is an integer of 1 or more and L or less, and L is 2 or 3, functions Fi=fi(P) and P=fi−1(Fi) are obtained beforehand for every i, said functions Fi=fi(P) and P=fi−1(Fi) being functions of an electrical output P of the fuel cell and a flow rate Fi of the hydrocarbon-based fuel required to be supplied to the reforming catalyst layer in order to output the electrical output P from the fuel cell when a reformed gas produced by the i-th reforming method is supplied to the fuel cell,where P=fi−1(Fi) is an inverse function of Fi=fi(P),
a function ηi=gi(P) is obtained beforehand for every i, said function ηi=gi(P) being a function of the electrical output P of the fuel cell and an electric power generation efficiency hi of the fuel cell when a reformed gas produced by the i-th reforming method is supplied to the fuel cell to output the electrical output P from the fuel cell, PiM represents a maximum electrical output of the fuel cell when a reformed gas produced by the i-th reforming method is supplied to the fuel cell, and Fimin represents a minimum value of a flow rate of the hydrocarbon-based fuel determined by the function Fi=fi(P) when P is within a range of 0 or more and PiM or less, the method of load following operation of the fuel cell system comprising: A1) measuring a temperature T of the reforming catalyst layer; B1) for every i, calculating a reformable flow rate FiR that is a flow rate of the hydrocarbon-based fuel capable of being reformed in the reforming catalyst layer at the temperature T by the i-th reforming method; C1) when the reformable flow rate FiR calculated in step B1 is smaller than the minimum value Fimin for every i, stopping electric power generation in the fuel cell; D1) when the reformable flow rate FiR calculated in step B1 is equal to or more than the minimum value Fimin for at least one i,for each of said at least one i, performing step d11 if a fuel cell output demand value PD is equal to or less than the maximum electrical output PiM, and performing step d12 if the fuel cell output demand value PD exceeds the maximum electrical output PiM,
d11) calculating a flow rate fi(PD) of the hydrocarbon-based fuel required to be supplied to the reforming catalyst layer, in which the i-th reforming method is performed, in order to output the fuel cell output demand value PD from the fuel cell, using the function Fi=fi(P), and if fi(PD) is equal to or less than the reformable flow rate FiR calculated in step B1, then setting Pi*=PD, and setting Fi*=fi(PD), and if fi(PD) exceeds the reformable flow rate FiR calculated in step B1, then setting Pi*={a value that is less than PD and the maximum among one or more P values calculated from a function P=fi−1(FiR)} and setting Fi*=FiR, d12) calculating a flow rate fi(PiM) of the hydrocarbon-based fuel supplied to the reforming catalyst layer required to be supplied to the reforming catalyst layer, in which the i-th reforming method is performed, in order to output the maximum electrical output PiM from the fuel cell, using the function Fi=fi(P), and if fi(PiM) is equal to or less than the reformable flow rate FiR calculated in step B1, then setting Pi*=PiM, and setting Fi*=fi(PiM), and if fi(PiM) exceeds the reformable flow rate FiR calculated in step B1, then setting Pi*={a value that is the maximum among one or more P values calculated from the function P=fi−1(FiR)}, and setting Fi*=FiR; E1) when there exist two or more i for which the reformable flow rate FiR calculated in step B1 is equal to or more than the minimum value Fimin, calculating ηi=gi(Pi*) that is an electric power generation efficiency at the electrical output Pi*, using the function ηi=gi(P), for each of said two or more i, and representing i that gives the largest hi among thus calculated ηi as I, and setting an electrical output of the fuel cell to PI*, setting a reforming method performed in the reformer to an I-th reforming method, and setting a flow rate of the hydrocarbon-based fuel supplied to the reforming catalyst layer to FI*; and F1) when there exists only one i for which the reformable flow rate FiR calculated in step B1 is equal to or more than the minimum value Fimin, representing said only one i as I, and setting the electrical output of the fuel cell to PI*, setting the reforming method performed in the reformer to an I-th reforming method, and setting the flow rate of the hydrocarbon-based fuel supplied to the reforming catalyst layer to FI*. |
