Electricity generator for vehicles using formic acid and an AFC fuel cell.
1. The vehicle tank consists of several cylinders with:
- formic acid destined to be decomposed into H2 and CO2,
- liquid CO2.
A moving piston separates the two liquids.
During use, formic acid decreases and CO2 increases.
At the filling station, a pistol with two ports simultaneously allows the reverse operation: fill in formic acid and evacuate liquid CO2.
An expandable envelope surrounds the tank and fills in it of CO2 in case of excessive pressure of it.
At the head of each cylinder, one can place a valve with gauge.
2. The dissociation of formic acid (HCOOH) in hydrogen (H2) and carbon dioxide (CO2).
Can be carried out at low temperatures using appropriate catalysts and by using the heat produced by the fuel cell. (*)
The following method allows high pressures and does not produce carbon monoxide (CO) (**)
Patent number: 8133464
Patent Application Number: 20100068131
Assignee: Federal Polytechnic School of Lausanne (EPFL) (Lausanne)
Inventors: Laurenczy Gabor, Celine Fellay, Paul Dyson
(*) If compared with methanol, reforming thereof, being performed at 270 ° C with catalyst, requires 10 to 15% of the available energy.
(**) Experience has shown that CO2 is liquefied.
3. The fuel cell.
In the example (see figure) is an alkaline fuel cell (AFC) has been chosen, primarily to reduce the cost of the electrodes, but also for performance.
The electrolyte is traditionally KOH solution, this poses the problem of carbonates because CO2 from the air.
Electrolyte regeneration (in the case of a AFC):
There are several possibilities:
- capture CO2 before the entry of air into the stack,
- regularly drain the electrolyte and replace,
- separate and treat carbonates directly in the vehicle.
The methods and procedures for this do exist in the literature.
As has "hot" and "cold", a method based on the difference in solubility depending on temperature could be studied.
4. Regeneration of CO2 to formic acid.
Several processes, including:
1) The most recent:
Direct synthesis of formic acid from carbon dioxide by hydrogenation in acidic media
2) Another method:
"One of the processes on the scale of the research laboratory to produce formic acid from CO2 (up 3.5 million catalytic cycles) using an iridium catalyst
(III) in the presence of potash, high pressure CO2 and hydrogen (50 bar and 120 ° C). "