Increasing Fuel Efficiency of Direct Methanol Fuel Cell Systems with Feedforward Control of the Operating Concentration

Abstract

Most of the R&D on fuel cells for portable applications concentrates on increasing efficiencies and energy densities to compete with other energy storage devices, especially batteries. To improve the efficiency of direct methanol fuel cell (DMFC) systems, several modifications to system layouts and operating strategies are considered in this paper, rather than modifications to the fuel cell itself. Two modified DMFC systems are presented, one with an additional inline mixer and a further modification of it with a separate tank to recover condensed water. The set point for methanol concentration control in the solution is determined by fuel efficiency and varies with the current and other process variables. Feedforward concentration control enables variable concentration for dynamic loads. Simulation results were validated experimentally with fuel cell systems.

Numerical Investigations of the Combined Effects of Flow Rate and Methanol Concentration on DMFC Performance

“…With a constant input methanol concentration, e.g., 1.0 mol/L as shown in Figure 6a, the overall color of current density distribution becomes lighter and brighter with the increase of input flow rate. It is in good agreement with the experimental evidence that the more the methanol (fuel) is pumped into a certain energy conversion system, the more the energy can be generated [9,10,18]. With a constant input flow rate, the low current density region (in dark blue) decreases gradually with the increase of input methanol concentrations, which is apparent for a low input flow rate of 1.0 mol/L (see the left column of Figure 6).…”

“…A typical DMFC is primarily composed of a Polymer Electrolyte Membrane (PEM), the catalyzed electrodes at anode/cathode sides and the end plates, as shown in Figure 1. The understanding of energy conversion process is necessary for optimal operation and design, but it is a task full of challenges as it normally involves lots of operating parameters, such as the feed solution properties [9] and the flow characteristics [10]. As the underlying mechanism of such a multi-parameter dependent system is usually hard to be experimentally determined, the comprehensive modelings of DMFC systems are essential in optimization design and operational management.…”

Liquid Hydrocarbon Production from CO2: Recent Development in Metal‐Based Electrocatalysis

“…[166] SinceC H 3 OH can be stored under ambient conditions, it can be readily integrated within current fuel cell technologies, such as direct methanol fuel cells (DMFCs), to generate electricity. [176][177][178][179] Apart from itsu tilization as as toragem edium, CH 3 OH itself is also an important chemical, consumed in several processes as af eedstocki np roducing consumable goods such as silicones, paints, plastics,a nd pharmaceutical products. [180] At present,t he majority of CH 3 OH is produced by using the well-established FT process from natural gas.…”

Studies on Influence of Cell Temperature in Direct Methanol Fuel Cell Operation

“…Advanced control strategies based on methanol concentration were designed and implemented to increase the efficiency of a DMFC. This method is more efficient than performing several modifications to system layouts and operating strategies [13]. In addition to the control of an integrated fuel processing system, the fuel cell system in a DMFC provides efficient fuel cell operation and sustainable power source for various utilities [14].…”