JPH02119061A - Methanol reformer of fuel cell - Google Patents

Abstract

PURPOSE:To increase load response capability by detecting increase in a load of a cell and thermal instability in a reformer, vaporizing a specified amount of mixed solution by heat exchange with reformer flue gas, and supplying the vaporized gas to a gas burner. CONSTITUTION:Increase in a load is detected with a load current detector 9, and a pump 5 is driven and control valves 7 is opened with an arithmetic output signal of a controller 10. A specified amount of mixed solution is vaporized while it flows in a branch passage 6 with a heat exchanger 8 which is heated with a flue gas, and the vaporized gas is supplied to a gas burner 2 as additional fuel. The supply amount of a reformed fuel is increased with a control valve 11, and fuel gas corresponding to a load is supplied from a reformer to quickly follow load variation. Even when heating value in the reformer is decreased by drop in a flow rate of exhaust fuel gas caused by condensed water in the passages or valves, this is also detected and solved in the same way.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention relates to methanol fuel reforming for a fuel cell power generation system;

(b) In the conventional technology methanol reformer, the burner fuel at startup is
The same fuel as reformed fuel is used due to unification of fuel tanks and fuel safety issues. This is a mixture of methanol and water at a molar ratio of 1:1.34. In the case of such methanol combustion, the atomization combustion method using single force spray is adopted due to poor ignition, but there is a key point in controlling the flow rate, especially when controlling the flow rate of a small amount, the pressure decreases and the spray becomes combustible. It is impossible to take any form. Therefore, the spray nozzle
Selected according to maximum fuel flow rate.

- Burner fuel during battery operation is the exhaust gas of the fuel gas generated in the reformer and supplied to the battery, which is combusted in the gas burner to improve the fuel efficiency of the entire power generation system.

However, due to an increase in load during steady operation, the burner PA
! Due to insufficient quantity, the amount of fuel gas generated by the reformer is insufficient and cannot follow load fluctuations. In this case, pj with a spray burner
It is virtually impossible to compensate for the % loss due to the characteristics of the atomizing burner as described above.

(c) Problems to be Solved by the Invention The present invention solves the above-mentioned problems and provides a methanol reforming device for a fuel cell with excellent load responsiveness.

(d) Means for Solving the Problems The present invention provides a reformer that vaporizes and reformes a mixture of methanol and water to generate fuel gas to be supplied to a fuel cell, and a reformer that combusts the mixture at startup. It is equipped with a reforming burner consisting of a spray burner and a gas burner that burns the exhaust gas of the fuel gas when the battery is activated, and detects when the load on the battery increases or when there is thermal instability in the reformer, A route is provided for replenishing a predetermined amount of the liquid to the gas burner through vaporization 1 through heat exchange with the reformer flue gas.

(E) Function In the present invention, a mixture of methanol and water is vaporized by heat exchange with the reformer flue gas, and this is supplied to a fuel gas burner for fuel gas (reformed gas) discharged from the battery. By simultaneously burning the fuel, the insufficient heating of the reformer is compensated for and the load followability of the battery is improved.

(f) The practical example of the electric power system is a methanol/water mixture fuel tank (T
), a reformer (RF), a fuel cell (FC) and an inverter (INV).

The burner of the reformer (RF) has a spray burner (1) that burns the liquid mixture and a gas burner (2) that burns the fuel gas discharged from the battery (FC).

When the system is started, the mixed liquid in the tank (T) is burned in the spray burner (1), and when the temperature inside the reformer reaches a predetermined value, the mixed liquid is used as reformed fuel in the vaporization section (3) inside the reformer. It is then supplied to the reforming section (4). This liquid mixture is vaporized and reformed to produce hydrogen-rich gas, which is supplied to the cell (FC) as fuel gas.

In this way, when fuel gas is generated from the reformer (RF), combustion in the spray burner (1) is stopped and the battery (
The exhaust fuel gas from F'C) is supplied to the gas burner (2) and combusted to serve as a heat source for the reformer.

In the present invention, a path (6) is provided from the downstream side of the pump (5) that supplies the mixed liquid to the spray burner (1) through a branch 1 to the gas burner (2), and this path (6) has a regulating valve. (
7) and a heat exchange section (8) with the reformer flue gas are interposed.

If the load (+-) increases and the fuel gas utilization rate improves, the combustion of the exhaust fuel gas in the gas burner will become unstable, and the amount of heat in the reformer will be insufficient, causing the reformed gas to The amount generated also decreases, making it impossible to follow load fluctuations.

Therefore, in the present invention, an increase in load is detected and controlled by p and load current detection 1s (9). The control valve (7) is opened at the same time as the ribbon valve (5) is driven by the calculation output signal of the M device (10).

In this state, while flowing through the branch path (6), a predetermined amount of the mixed liquid is immediately vaporized in the heat exchange section (8), which is constantly heated with flue gas, and is supplied to the gas burner (2) as additional fuel. Ru. At the same time, the supply amount of reformed fuel is adjusted by the regulating valve (1
1), the fuel gas is increased by a predetermined amount and sent out from the reformer (RF) according to the load to quickly follow load fluctuations.

In addition to load fluctuations, if the flow rate of exhaust fuel gas decreases due to moisture condensed in the pipes or valves, resulting in a lack of heat in the reformer, this will be detected and dealt with in the same way as above. can.

(g) Effects of the Invention - As described above, according to the present invention, when the battery load increases or the temperature in the reformer becomes unstable, this is detected and the mixed fuel is transferred to the heat of the reformer flue gas. By exchanging it, it can be vaporized and combusted in a gas burner along with the battery exhaust fuel gas, making it possible to compensate for the lack of heat in the reformer and improve response to load fluctuations. Improvement in characteristics has not been achieved.

[Brief explanation of drawings]

The drawing is a block diagram of a fuel cell power generation system equipped with the methanol reformer of the present invention. T, mixed liquid tank, RF: reformer, FC: fuel cell,
INV: Inverter, 1: Spray burner, 2: Gas burner, 3: Vaporization section, 4: Reforming section, 5: Combustion fuel supply pump, 6: Branch path, 7.11: Regulating valve, 9: Load detector , lO2 control group

Claims (1)

[Scope of Claims] 1. A reformer that vaporizes and reforms a mixture of methanol and water to generate fuel gas to be supplied to a fuel cell, a spray burner that burns the mixture at startup, and when the battery is in operation. and a reforming burner consisting of a gas burner that burns the exhaust fuel gas of the battery, and detects when the load on the battery increases or when there is thermal instability in the reformer and adjusts the predetermined amount of the mixed liquid. . A methanol reforming device for a fuel cell, comprising a path for vaporizing the gas by heat exchange with the reformer flue gas and replenishing the gas burner. 2. The methanol reforming device for a fuel cell according to claim 1, wherein the path branches from a downstream side of a supply pump that sends the mixed liquid to the spray burner, and has a regulating valve.