For over 10 years, ZSW has been developing fuel cell systems using a wide range of fuels, such as natural gas, LPG, ethanol, methanol or dimethyl ether. ZWS’s experience spans the entire process chain from the reformer and gas treatment stages to the integration of the overall system.
One of the highlights was the development of a 1 kWel FlexFuel fuel cell system, which can be run on bio-ethanol or LPG and can provide electricity and heat without a mains connection. The systems can be used as auxiliary power units, battery chargers or on-board power supplies for vehicles.
Another fine example of ZSW’s innovations is the 4 kWel fuel cell system that is powered by natural gas and used for combined heat and power (CHP) applications for the domestic energy supply. These microCHP plants with outputs from 1 to 5 kWel could make a major contribution to climate protection and to relieving the load on the mains grid. They provide a flexible means to supplement and compensate the fluctuating yield of electricity generated from the wind and sun. This can also be realised by converting the gas generated using the Power-to-Gas (P2G®) process back to electricity in a highly efficient process. Of all microCHP technologies, fuel cell heating units achieve the best electrical efficiency and thus leave the smallest carbon footprint. Between 2008 and mid-2016, in its capacity as project coordinator and scientific advisor of the flagship project Callux ZSW helped to prepare these devices for the market.
ZSW also develops and optimises processes for treating and conditioning renewable gases using a membrane technology. The processes are based on the variable permeation of gas components through membrane materials. The key benefits of this technology include extremely simple design, the almost maintenance-free and uncomplicated handling, and also the resulting high reliability. Therefore, the process is even suitable for small, decentralised treatment systems. An example of its use is the treatment of crude biogas to produce bio natural gas that can be fed into the grid. The major gas components of the crude gas, i.e. methane (CH4) and carbon dioxide (CO2), must be separated before the gas is fed in. The technology can also be used in the (P2G®) process to condition the product gas, if residual H2/CO2 needs to be separated from the methane.
ZSW’s research and development work covers the design, construction, characterisation and optimisation of combined systems suitable for this task of separating gases. In development projects, prototypes of container-integrated system have already been successfully installed and have treated biogas outputs of up to 100 kW. Membrane treatment stages also form part of ZSW’s 250 kW P2G® system.