KR100422660B1 - System for withdrawing energy in fuel reformer for fuel cell car - Google Patents

Abstract

An object of the present invention is to recover the energy of the raffinate supplied from the reactor to the combustion chamber and to use this energy as a power source of the compressor for supplying the air required for the combustion chamber, thereby increasing the energy efficiency of the fuel cell vehicle fuel converter To provide an energy recovery system.

Accordingly, the present invention provides a reactor in which a reforming reaction is performed through fuel, a separator provided in the reactor for selectively passing only hydrogen gas in the reforming gas, and a combustion chamber in which a combustion catalyst is installed outside the reactor to provide heat required for the reactor. A fuel converter comprising: a air supply means for supplying air to the combustion chamber by converting the energy according to the movement of the raffinate is installed on the raffinate transfer line connected to the combustion chamber in the reactor to the rotational energy; It provides an energy recovery system of a fuel converter for a fuel cell vehicle, characterized in that.

Description

Energy recovery system of fuel converter for fuel cell vehicle {SYSTEM FOR WITHDRAWING ENERGY IN FUEL REFORMER FOR FUEL CELL CAR}

The present invention relates to a small fuel converter for a fuel cell vehicle using a metal thin film for providing hydrogen to a fuel cell vehicle using methanol, ethanol, alcohol, etc., more specifically, to recover the energy wasted in the fuel converter The present invention relates to an energy recovery system of a fuel converter for a fuel cell vehicle, which can improve the efficiency of the system.

The steam reforming reaction for hydrogen generation and the separation reaction for hydrogen separation are simultaneously performed in the same reactor using the characteristics of the metal membrane that selectively permeates only hydrogen in the reformed gas mixed with hydrogen and the reaction rate in the unbalanced state. The present invention relates to a compact fuel converter for a fuel cell vehicle and a system using a metal thin film to reduce the size of the entire apparatus by employing a reaction / separation integrated fuel converter.

In general, a fuel cell is an energy conversion system that generates electric power as part of a chemical reaction between gas and electrolyte of diesel or industrial fuel and converts chemical energy of the fuel directly into electrical energy. It is a power generation system that can continue to generate electricity as long as fuel is supplied without the need for recharging.

A fuel cell is a sandwich of an electrolyte and two electrodes stacked together like a sandwich. When oxygen and hydrogen flow into each electrode, electricity, heat and water are produced. It is used as a system for supplying electric power to fields or electric vehicles that are not practically used.

Various fuels such as natural gas, methanol, gasoline, and the like may be used in the fuel cell, and the fuel may be reformed into hydrogen using a fuel converter.

As interest in energy efficiency and environmental pollution has increased recently, electric vehicles using fuel cells are expected to replace internal combustion engine vehicles, and reformed liquid fuels such as methanol, ethanol and gasoline according to this trend. Therefore, the development of a fuel converter for a fuel cell vehicle, which generates hydrogen and separates only hydrogen, is used as a fuel of a fuel cell.

2 is a conceptual view illustrating a fuel converter according to the prior art, the fuel converter 10 includes a reactor 11 through which fuel is introduced to perform a reforming reaction, and a separator provided in the reactor to selectively pass only hydrogen gas in the reformed gas. (12), a combustion chamber (13) installed outside the reactor and containing a combustion catalyst for providing heat required for the reactor by the reformed gas and air provided from the reactor and the air supply (14).

Therefore, the fuel (feed; water and methanol mixture) supplied from the outside into the reactor receives the heat source from the combustion chamber 13 to evaporate to form a vapor state and reacts with the catalyst to be converted into hydrogen and carbon dioxide, generated in the reactor 11 Only hydrogen among the hydrogen and carbon dioxide passes through the separator 12 to the place of use, and the raffinate (mixed gas of hydrogen and carbon dioxide) that has not passed through the hydrogen separator of the reactor is transferred to the combustion chamber 13 ( It is sent to the combustion chamber 13 through the flow path switching valve 15 installed in 14) is used as fuel to supply heat to the reactor and is discharged to the atmosphere.

Here, the driving force for moving hydrogen through the separator is the pressure and concentration difference between both sides of the separator, and is usually about 10 bar, and about 1/3 of hydrogen generated in the reactor and gas other than hydrogen are sent to the combustion chamber for oxidation. Let's go.

However, the conventional structure described above uses a raffinate having significant energy (flow rate 25 Nm ³ / hr, pressure 10 bar, temperature 300 ° C.) to 10 bar using a flow path switching valve or throttling. As a result of lowering the pressure near the atmospheric pressure and supplying it to the combustion chamber, energy loss of the raffinate is generated, thereby reducing the efficiency of the system.

The present invention has been made to solve the above problems, by recovering the energy of the raffinate supplied from the reactor to the combustion chamber and using this energy as a power source of the compressor for supplying the air required for the combustion chamber, energy efficiency It is an object of the present invention to provide an energy recovery system of a fuel converter for a fuel cell vehicle that can be increased.

1 is a schematic view showing an energy recovery system of a fuel converter according to the present invention;

2 is a schematic diagram illustrating the concept of a fuel converter according to the prior art.

Explanation of symbols on the main parts of the drawings

10 fuel converter 11 reactor

12 Separation membrane 13 Combustion chamber

14: air supply 15: transfer line

20 turbine 21 motor generator

22: compressor 30: flow control valve

In order to achieve the object as described above, the present invention, the reactor in which the fuel is introduced to the reforming reaction, and the separator provided in the reactor to selectively pass only hydrogen gas in the reforming gas, installed outside the reactor to provide the heat required for the reactor In a fuel converter including a combustion chamber with a combustion catalyst for providing, the fuel converter is installed on the raffinate transfer line connected to the combustion chamber in the reactor to convert the energy of the movement of the raffinate into rotational energy to supply air to the combustion chamber It characterized in that it further comprises an air supply means for.

Here, the present invention may include a turbine in which the air supply means is installed on the raffinate moving line, and an air supply compressor connected to the power shaft of the turbine.

In another aspect, the present invention may further include a motor that the air supply means is connected between the turbine and the compressor for air supply.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a schematic diagram illustrating an energy recovery system of a fuel converter according to the present invention.

According to the above drawings, the fuel converter 10 has a fuel inlet through which liquid fuel such as methanol, ethanol or alcohol is introduced, and a reforming catalyst for reforming fuel introduced through the fuel inlet is filled therein to reform the fuel. Reaction membrane 11 for selectively reacting with the reactor 11 and the reformed gas is selectively separated and permeated and supplied to a stack of fuel cells through a separate discharge pipe connected to the reactor 11, on the outer peripheral surface of the reactor 11. It comprises a combustion chamber 13 installed and a combustion catalyst for providing heat to the reactor 11 for the hydrogen separation reaction.

In addition, the air supply 14 is connected to one side of the combustion chamber 13 to supply air for combustion, and the raffinate transfer line 15 is connected between the reactor 11 and the combustion chamber 13 to separate the membrane ( Raffinate, which is a reformed gas that does not pass 12), is transferred to the combustion chamber 13 and is used as a combustion raw material.

The present invention is the fuel converter 10 of the above-described structure, is installed on the raffinate transfer line 15 is connected to the combustion chamber 13 in the reactor 11 to rotate the energy according to the movement of the raffinate A compressor 20 and a turbine 20 for supplying air for supplying air to the combustion chamber 13 by receiving a driving force from the turbine 20 connected to the turbine 20 and the drive shaft of the turbine 20 for converting the gas into the combustion chamber 13. And a motor generator 21 connected to the power axis of the compressor 22 to transmit power to the compressor 22 or recover power to generate power according to the driving force of the turbine 20.

The motor generator 21 is capable of generating power or producing electric power. The motor generator 21 transmits the power of the turbine 20 to the compressor 22 as it is, according to the driving force of the turbine 20, that is, the flow rate of the raffinate. Drive 22 and produce power in this process, or if the drive force of the turbine 20 is insufficient to operate itself to supply additional power to the compressor 22.

Unexplained reference numeral 30 is a flow control valve installed on the raffinate transfer line 15.

Referring to the operation of the system of the present invention having such a configuration as follows.

In FIG. 1, the dashed line arrow indicates the fuel transfer line, the dashed line arrow indicates the transfer line of permeate, and the dashed line arrow indicates the raffinate transfer line 15.

Fuels such as alcohol, such as methanol and ethanol, vaporized in advance by an external fuel preheater (not shown) are introduced from the fuel inlet provided in the reactor 11, and the fuel thus introduced is the combustion heat supplied from the combustion chamber 13. It is heated to 150 to 600 ℃, which is the temperature required for the hydrogen separation reaction.

The fuel heated as described above is converted into a reforming gas composed of hydrogen and carbon dioxide, a small amount of carbon monoxide and excess water by performing a reforming reaction as shown in Scheme 1 below in contact with the reforming catalyst.

Scheme 1

CH ₃ OH (methanol) + H ₂ O + Q ⇔ 3H ₂ + CO ₂

Only the hydrogen is selectively permeated while the reformed gas passes through the separator 12, and the hydrogen separated from the remaining components of the reformed gas is supplied to the stack of the battery through the outlet. In addition, the raffinate, which is a reformed gas that does not penetrate the separation membrane 12, is supplied to the combustion chamber 13 along a transfer line 15 connecting the reactor 11 and the combustion chamber 13.

In addition, the reforming reaction as in Scheme 1 is an endothermic reaction that requires a lot of heat, the heat required for this is made by heat exchange with the heat of combustion generated in the combustion chamber 13, this heat of combustion is the raffinate transfer line It is obtained by being supplied to the combustion chamber 13 through 15 and used as a fuel.

That is, the raffinate generated in the reactor 11 and not passing through the separator 12 contains about 1 to 70% of hydrogen depending on the operating conditions of the reactor 11, and thus may be used as fuel in the combustion chamber 13. It is.

Meanwhile, the raffinate introduced into the combustion chamber 13 along the transfer line 15 has energy of about 25 Nm ³ / hr, a pressure of 10 bar, and a temperature of about 300 ° C., and thus the turbine 20 installed in the transfer line 15. While passing through the high temperature and high pressure state is changed to the low pressure state at this time the energy of the raffinate is converted into the rotational energy of the turbine 20 is to rotate the turbine 20 at high speed.

The rotational force of the turbine 20 is transmitted to the compressor 22 via the motor generator 21 connected to the drive shaft of the turbine 20 to operate the compressor 22, and the air is driven by the compressor 22 to operate the combustion chamber 13. Or can be supplied as a stack of batteries.

In addition, according to the operation of the turbine 20, the motor generator 21 rotates to produce electric power, and the generated electric power is supplied to the air supply 14 to operate a blower of the supply 14. This eliminates the need for an external power supply for blower operation.

In this case, when the amount of raffinate introduced into the combustion chamber 13 through the transfer line 15 is small, the driving force of the turbine 20 for operating the compressor 22 is not sufficient. In this case, power is supplied to the motor generator 21. When the power is applied to generate power, the power is added to the driving force of the turbine 20 so that the compressor 22 can be operated.

The above-mentioned system is provided with both the compressor 22 and the air supply 14, wherein the air discharged from the compressor 22 is supplied to the combustion chamber 13 of the fuel converter 10 and from the air supply 14. Outgoing air may be supplied to the stack of cells or, conversely, air of the compressor 22 may be supplied to the stack of cells and air of the air supply 14 may be supplied to the combustion chamber 13.

Alternatively, it may be constructed as a system for supplying air to both the combustion chamber 13 and the stack by the compressor 22 alone without the air supply 14.

Example

Based on the 30 Kw class system, the turbine 20 recovers energy from the high temperature and high pressure raffinate, which is about 2.4 kw.

Calculation of gas constant of raffinate

ingredient volume(%) Mole fraction Molecular Weight Mass per kmol Mass-based analysis value H ₂ 50 0.5 2.0 1.0 0.043 CO ₂ 50 0.5 44.0 22.0 0.957

Formula: w = -k × R × T ₁ / (k × 1) × {(P ₂ / P ₁ ) ^{((k-1) / k)} -1}

(Assuming k = 1.3, P ₁ = 10 bar, P ₂ = 1 bar)

Raffinate Gas Constant R = 8.3144 / 23 0.3615 kJ / kgK

Raffinate Flow Rate 25 Nm ³ / hr 0.006638 kg / sec

W = 370.0 kw / kg during reversible insulation

Expansion Date of Raffinate W = 2.456 kw / (25 Nm ³ / hr)

Considering that the blower maximum demand output of the air supply 14 that supplies air to the reactor 11 or stack is about 1.2 kw, the power supplied from the outside even if the efficiency of the turbine 20 is about 50%. Air supply is possible without.

According to the energy recovery system of the fuel cell vehicle fuel converter 10 according to the present invention as described above, the energy of the discarded raffinate can be utilized to increase the efficiency of the system.

Claims (3)

delete delete Fuel including a reactor into which the fuel is introduced to undergo a reforming reaction, a separator provided in the reactor to selectively pass only hydrogen gas from the reforming gas, and a combustion chamber installed outside the reactor to provide heat required for the reactor. In the energy recovery system of the converter, A turbine installed on the raffinate transfer line and driven by the movement of the raffinate; A compressor for supplying air connected to a power shaft of the turbine and driven by kinetic energy generated by the turbine; And And a motor generator installed between the turbine and the compressor for supplying air and transmitting power generated by the rotation of the turbine to an air supply.