CN1741310A

CN1741310A - Method for fluid-bed electrode directly carbon converting fuel battery and converting device

Info

Publication number: CN1741310A
Application number: CNA2005100410473A
Authority: CN
Inventors: 仲兆平; 金保升; 黄亚继
Original assignee: Southeast University
Current assignee: Southeast University
Priority date: 2005-07-15
Filing date: 2005-07-15
Publication date: 2006-03-01
Anticipated expiration: 2025-07-15
Also published as: CN100347891C

Abstract

A method of using fluidized bed to directly convert carbon to be fuel cell includes preparing positive and negative electrodes of three phase fluidized bed , setting metal cylinder on each said electrode ; using carbonate as electrolyte and nickel powder as catalyst ; placing carbon powder particle , catalyst particle and electrolyte in positive electrode ; placing catalyst particle and electrolyte in negative electrode ; heating and leading CO2 to positive electrode as well as mixed gas of CO2 and air to negative electrode ; carrying on electrochemical reaction for obtaining fuel cell . The device for realizing the method is also disclosed .

Description

Method and device for converting fluidized bed electrode direct carbon into fuel cell

Technical Field

The invention relates to a technology for converting direct carbon of a fluidized bed electrode into a fuel cell, in particular to a method and a device for converting direct carbon of the fluidized bed electrode into the fuel cell.

Background

With the continuous and rapid development of national economy, the clean and efficient utilization of energy becomes a very urgent problem. The traditional way of utilizing energy is to first chemically react the fuelThe energy can be converted into heat energy and then into mechanical energy and electric energy, the power generation efficiency is only about 30 percent due to the restriction of Carnot cycle and materials, and serious wastewater, waste gas, waste residue, waste heat and noise pollution are generated in the power generation process. The fuel cell is a device for directly converting chemical energy in fuel and oxidant into electric energy, is not limited by Carnot cycle, and has the power generation efficiency of 50-70%; compared with the traditional thermal power generating unit: NOx (<2ppm) and SO₂Very little (<1ppm) emissions, CO₂The emission can be reduced by 40-60%, and the noise is low (less than 60 dB); a modular structure; the variable load rate is high (20-120%); the power supply can be centralized and distributed; the occupied area is small. Therefore, the fuel cell is referred to as a fourth generation power generation device following hydroelectric, thermal, and nuclear power. Fuel cells are expected to play an important role in the fields of electric power, automobiles, communications, and computers for national defense and civilian use.

Fuel cells have received much attention from governments and enterprises in developed countries because of their outstanding advantages of high energy conversion efficiency, minimal pollution, low water usage, small footprint, etc. At present, China is the world CO₂Gas emission second major country, CO emission reduction₂The pressure is very great, the energy is efficiently utilized, and the CO is greatly reduced₂Is one of the effective measures for emission.

In the early century, scientists, represented by professor j.f. cooper, Lawrance national laboratory, usa, have been working on developing a new fuel cell directly fueled with carbon powder. Since the solid fuel does not need to be gasified, the cost of the whole system is greatly reduced, and the battery is highly valued by researchers and scholars of fuel cells. The fuel cell is based on a Molten Carbonate Fuel Cell (MCFC), the cathodeStill introducing air and CO₂The anode is changed from the original hydrogen flow to the direct addition of carbon powder prepared from biomass (or coal), and the research of Cooper et al shows that: the direct carbon reforming fuel cell can obtain the current density which is equivalent to that of the molten carbonate fuel cell using hydrogen as fuel under the same cell voltage, which shows that the direct carbon reforming fuel cell has quite attractive scenes.2003 American Scientific Applications&Strahinja Zecevic et al, by Research Associates (SARA), reported direct carbon reforming fuel cells based on metal hydroxides as the electrolyte. Thomas Tao from CellTech Power, USA, is also under investigation for direct carbon reforming fuel cells. At the end of the last ninety years of the last century, a great deal of research work was conducted on fluidized bed electrodes as fuel cell electrodes by y.matsuno, Kyushu, Katsuki, Newcastle university, usa, t.berent, et al.

Disclosure of Invention

The invention provides a method and a device for converting fluidized bed electrode direct carbon into a fuel cell, which can improve current density.

The invention adopts the following technical scheme:

the method of the invention comprises the following steps: a method for directly converting carbon into fuel cell by fluidized bed electrode includes such steps as separating the cathode and anode by microporous metal partition plate to form three-phase fluidized bed, putting the metal cylinders with holes on them in said cathode and anode, using carbonate as electrolyte and Ni powder or Ni-Cr alloy powder as catalyst, putting the carbon powder particles, catalyst particles and electrolyte in anode, putting them in cathode, heating to melt the electrolyte, introducing the carbon dioxide as anode fluidizing gas to anode, introducing the mixture of carbon dioxide as cathode fluidizing gas and air to cathode, and electrochemical reaction to convert it into fuel cell.

The conversion device of the invention is that: the conversion device for implementing the method for directly converting the carbon into the fuel cell by the fluidized bed electrode comprises a reaction cylinder, a heater is arranged on the reaction cylinder, a microporous partition board is arranged in the reaction cylinder and divides the reaction cylinder into an anode chamber and a cathode chamber, an anode current collector is arranged in the anode chamber, a cathode current collector is arranged in the cathode chamber, the anode current collector and the cathode current collector are both metal cylinders, holes are arranged on the metal cylinders, an anode fluidizing gas inlet is arranged at the bottom of the anode chamber, an anode fluidizing gas outlet is arranged at the top of the anode chamber, the bottom of the cathode chamber is provided with a cathode fluidizing gas inlet, the top of the cathode chamber is provided with a cathode fluidizing gas outlet, an electrolyte is placed in the anode chamber and the cathode chamber, carbon powder particles and catalyst particles are placed in the anode current collector, and catalyst particles are placed in the cathode chamber.

Compared with the prior art, the invention has the following advantages:

the present invention achieves transformation based on the following principles:

the anode reaction is as follows:

the cathode reaction is as follows:

the overall cell reaction for a direct carbon conversion fuel cell is:

the invention puts carbon powder particles, catalyst particles, electrolyte and a current collector into an anode, puts the catalyst particles, the electrolyte and the current collector into a cathode, utilizes an external electric heating system to heat the fuel cell, and leads CO into the anode after the electrolyte is melted₂Air and CO are introduced into the cathode₂Mixture (CO)₂The concentration is 10-50%) to form a gas, liquid and solid three-phase fluidized bed electrode; the anode and cathode are separated by a microporous separator which prevents particle exchange between the two electrodes, but permits diffusion of carbonate ions; the current collectors in the cathode and the anode are connected by a wire, an ammeter is arranged in a connecting circuit to indicate the generated current, and the gas, liquid and solid three-phase fluidized bed electrode has good heat and mass transfer effects and small boundary layer diffusion resistance, and compared with the conventional fixed bed electrode, the current density can be improved by 20-30%. In addition, the present invention adopts carbon powder with wide material source and relatively low cost to replace conventional fuel cellThe high-quality gas fuel which is difficult to store and transport saves the fuel gas reforming link through direct carbon conversion, and the operation cost is lower. Use can realize CO₂Carbon powder prepared from the biological circulating biomass is used as fuel and can realize CO₂Zero emission of (2). The carbon powder is subjected to fine treatment such as devolatilization, ash removal and the like, SO that the emission of other environmental pollutants such as SO2, NOx and the like of the fuel cell is extremely small. And current collectors which are large in surface area and small in influence on electrochemical reaction are arranged in the cathode and the anode, so that the current collection efficiency is high. The mixed carbonate or hydroxide is used as electrolyte, the bed temperature can be kept at a lower level, and the equipment investment cost is correspondingly reduced. The microporous separator between the cathode and the anode has the following structure: a plurality of micropores are formed in one metal plate, the micropores are uniformly distributed in an isosceles triangle shape, the aperture is directly equivalent to that of a carbonate ion group, and the distance between the pores is 2-5 times of the aperture. The microporous partition board between the cathode and the anode is made of the following materials: nickel or nickel-chromium alloy, its advantage is: can replace noble metals as partial catalysts of electrochemical reaction.

Drawings

Fig. 1 is a schematic structural diagram of an embodiment of the present invention.

Fig. 2 is a schematic view of the structure of the microporous metal separator of the present invention.

Detailed Description

Example 1

A fluidized bed electrode direct carbon conversion fuel battery method, separate and form the negative pole 9 and positive pole 5 of the three-phase fluidized bed with the metal baffle of the micropore, put metal cylinder equipped with hole on it separately in negative pole 9 and positive pole 5, as the current collector of negative pole current and positive pole, regard carbonate as the electrolyte, regard nickel powder or nichrome powder as the catalyst, put carbon powder granule 2, catalyst granule 3 and electrolyte 4 into positive pole 5, put catalyst granule 11 and electrolyte 10 into negative pole 9, heat it again, make the electrolyte melt, then, the carbon dioxide gas as the anode fluidizing gas is led into the positive pole, the carbon dioxide gas as the cathode fluidizing gas and mixed gas of the air are led into the negative pole, and the concentration of the carbon dioxide gas in the mixed gas is 10% -50%, after electrochemical reaction, turn into the fuel battery, in this embodiment, the carbonate may specifically adopt any one of the following four specific technical measures: (1) the carbonate comprises lithium carbonate and sodium carbonate, and the mass percentage of the carbonate is 20-50%: 50-80%, this embodiment can select 20%: 50%, 50%: 80% and 34%: 65% and 43%: 75% or 45%: 55 percent; (2) the carbonate comprises lithium carbonate and potassium carbonate, and the mass percentage of the carbonate is 20-50%: 50-80%, this embodiment can select 20%: 50%, 50%: 80% and 38%: 64% and 41%: 70% or 45%: 55 percent; (3) the carbonate comprises sodium carbonate and potassium carbonate, and the mass percentage of the carbonate is 20-50%: 50-80%,this embodiment can select 20%: 50%, 50%: 80% and 35%: 60% and 48%: 58% or 47%: 52 percent; (4) the carbonate is composed of lithium carbonate, sodium carbonate and potassium carbonate, and the mass percentage of the carbonate is 10-30%: 35-45%: 35-45%, this embodiment can select 10%: 35%: 35% and 15%: 37%: 43%, 20%: 40%: 40% and 22%: 43%: 37% or 30%: 45%: 45 percent; the carbon powder particles 2 adopt micron-sized carbon powder; the catalyst particles 3 adopt submicron nickel powder or nichrome powder.

Example 2

A conversion device for implementing the method of the fluidized bed electrode direct carbon conversion fuel cell comprises a reaction cylinder 15, a heater 7 is arranged on the reaction cylinder 15, a microporous partition 14 is arranged in the reaction cylinder 15, the reaction cylinder 15 is partitioned by the microporous partition 14 to form an anode chamber 5 and a cathode chamber 9, an anode current collector 11 is arranged in the anode chamber 5, a cathode current collector 12 is arranged in the cathode chamber 9, the anode current collector 11 and the cathode current collector 12 are both metal cylinders and are provided with holes, an anode fluidizing gas inlet 1 is arranged at the bottom of the anode chamber 5, an anode fluidizing gas outlet 1 is arranged at the top of the anode chamber 5, a cathode fluidizing gas inlet 13 is arranged at the bottom of the cathode chamber 9, a cathode fluidizing gas outlet 13 is arranged at the top of the cathode chamber 9, an electrolyte 4 is arranged in the anode chamber 5 and the cathode chamber 9, carbon powder particles 2 and catalyst particles 3 are arranged in the anode current collector 11, in the cathode chamber 9, catalyst particles 3 are placed, and in this example, the microporous separator 14 is a nickel or nickel-chromium alloy plate having micropores with a diameter corresponding to the carbonate ion diameter, for example: the aperture of the micropore cantake the same order of magnitude as the particle size of carbonate ion; the micropores are arranged in an isosceles triangle; the aperture of the holes on the anode current collector 11 and the cathode current collector 12 is 4mm-12 mm.

Claims

1. A method for converting carbon directly into fuel cell by fluidized bed electrode is characterized in that a cathode (9) and an anode (5) of a three-phase fluidized bed are separated by a microporous metal separator and formed, metal cylinders with holes are respectively arranged in the cathode (9) and the anode (5) to be used as a cathode current collector and an anode current collector, carbonate is used as electrolyte, nickel powder or nickel-chromium alloy powder is used as catalyst, carbon powder particles (2), catalyst particles (3) and electrolyte (4) are placed in the anode (5), catalyst particles (11) and electrolyte (10) are placed in the cathode (9) and then heated to melt the electrolyte, then carbon dioxide gas used as anode fluidizing gas is introduced into the anode, mixed gas of carbon dioxide gas used as cathode fluidizing gas and air is introduced into the cathode, and the concentration of the carbon dioxide gas in the mixed gas is 10-50%, after electrochemical reaction, the fuel cell is converted into a fuel cell.

2. The method for converting direct carbon into fuel cells by using fluidized bed electrodes as claimed in claim 1, wherein the carbonate comprises 20-50% of lithium carbonate and 50-80% of sodium carbonate by mass.

3. The method for converting direct carbon into fuel cells by using fluidized bed electrodes as claimed in claim 1, wherein the carbonate comprises 20-50% of lithium carbonate and 50-80% of potassium carbonate by mass.

4. The method for converting direct carbon into fuel cells by using fluidized bed electrodes as claimed in claim 1, wherein the carbonate comprises 20-50% of sodium carbonate and 50-80% of potassium carbonate by mass.

5. The method for converting direct carbon into fuel cells by using fluidized bed electrodes as claimed in claim 2, 3 or 4, wherein the carbonate is composed of lithium carbonate, sodium carbonate and potassium carbonate, and the mass percentage of the carbonate is 10-30% to 35-45%.

6. The method for direct carbon conversion fuel cell with fluidized bed electrode according to claim 1, characterized in that the carbon powder particles (2) are micron-sized carbon powder, and the catalyst particles (3) are submicron-sized nickel powder or nichrome powder.

7. A reformer for carrying out the fluidized bed electrode direct carbon reforming fuel cell process according to claim 1, comprising a reaction vessel (15), characterized in that a heater (7) is provided on the reaction vessel (15), a microporous partition (14) is provided in the reaction vessel (15) and the reaction vessel (15) is partitioned by the microporous partition (14) to form an anode chamber (5) and a cathode chamber (9), an anode current collector (11) is provided in the anode chamber (5), a cathode current collector (12) is provided in the cathode chamber (9), the anode current collector (11) and the cathode current collector (12) are each a metal cylinder provided with holes, an anode fluidizing gas inlet (1) is provided at the bottom of the anode chamber (5), an anode fluidizing gas outlet (1) is provided at the top of the anode chamber (5), and a cathode fluidizing gas inlet (13) is provided at the bottom ofthe cathode chamber (9), a cathode fluidizing gas outlet (13) is provided at the top of the cathode chamber (9), an electrolyte (4) is placed in the anode chamber (5) and the cathode chamber (9), carbon powder particles (2) and catalyst particles (3) are placed in the anode current collector (11), and catalyst particles (3) are placed in the cathode chamber (9).

8. The reformer according to claim 7, characterized in that the microporous separator (14) is a nickel or nickel-chromium alloy plate with pores having a diameter corresponding to the carbonate ion diameter.

9. The conversion apparatus of claim 7, wherein the micropores are arranged in an isosceles triangle.

10. The reformer according to claim 7, characterized in that the apertures in the anode current collector (11) and the cathode current collector (12) are between 4mm and 12mm in diameter.