Electricity from hydrogen for infrastructure – Flexible KNF diaphragm pumps for scalable fuel cell systems.
For 25 years, Proton Motor Fuel Cell GmbH has been working on solutions for the energy challenges of our time. Europe’s expert for modular fuel cell premium products “Made in Germany” relies on KNF pumps for hydrogen recirculation, which is decisive for the efficiency of the energy system.
Proton Motor develops and produces in the field of energy supply with customer-specific hydrogen fuel cells. The technology is one of the possible solutions for a grid-independent or decentralized power and emergency power supply.
Central component for emission-free hydrogen applications: the fuel cell stack
Regardless of the actual application and the required power level, every hydrogen solution at Proton Motor starts with the stack, the cell stack.
The active area of a cell determines how much electrical energy the stack or cell stack can provide through the amount of simultaneous reactions. The corresponding voltage is a result of the number of interconnected cells.
In this way, the stack modules from Proton Motor currently provide an electrical output of 1.8 to 42.6 kW. The company’s future plans include a further increase in performance, in particular through the use of multistacks.
Recirculating hydrogen gas with high-density, maintenance-free KNF diaphragm pump
The mode of operation of the fuel cell systems is the recirculation mode. The introduction of more hydrogen into the anode input than is consumed in the process prevents an undersupply of the anode with changing current load.
Proton Motor currently uses KNF N 10.6.838 diaphragm gas pumps in systems with an output of up to 1.2 kW to feed excess hydrogen gas back into the fuel cell stack.
At the anode outlet, the gas pump N 838.1.2 absorbs the unused hydrogen. The condensate remains in the separator. The remaining hydrogen gas mixture compresses the N 838.1.2 to the required anode inlet pressure and recirculates it into the stack.
The KNF recirculation pump ensures that the hydrogen used can be used almost completely. This optimizes hydrogen consumption and has a positive effect on the efficiency of the overall system.
The requirements of hydrogen for the diaphragm pump
The energy carrier hydrogen places specific demands on the recirculation pump.
The wetted components of the pump – pump head, wiring and connection plate – are made of 316L stainless steel. This prevents unwanted material embrittlement and the leaching of harmful components.
The density of hydrogen is low; in addition, this changes depending on the operating point. The pump head is adapted to the characteristics of the hydrogen and thus remains reliably sealed.
The protection class IP 20 of the standard version has been increased to IP 44. For this purpose, the motor receives an additional flange, special motor cable glands and a separate terminal box. Another adaptation that enables the KNF modular system in a time- and cost-efficient manner is the equipment with gas-tight screw connection.
Dynamic pump characteristics for different operating states
The operating modes start-up, normal operation and shutdown or stand-by result in different amounts of hydrogen gas to be returned.
The KNF recirculation pump is equipped with a motor from the Digital Customization series. This precisely controllable motor gives the maintenance-free recirculation pump the necessary flexibility to achieve the respective flow rate of anode gas with the best possible energy efficiency.
The system pressure is up to 400 mbar g – the brushless DC motor, developed in-house by KNF, copes very well with this prepressure. A soft start is possible, the current consumption remains under control at all times and there are no current peaks.
Modular fuel cell systems with the need for compact hydrogen pumps
Proton Motor pays attention to the size when selecting the anode gas pump. The production model of the diaphragm gas pump N 838.1.2. is already compact. Modifications to the interconnection of the pump head have additionally streamlined the recirculation pump, the space requirement is further reduced. This option perfectly supports the modular design of the CleanTech company.
Hydrogen for off-grid power supply and emergency power supply
Proton Motor’s scalable fuel cell solutions can be used stationary and mobile. They can be used both indoors and outdoors as a turnkey cabinet solution.
In addition to the application as an emergency power system, the emergency power supply of critical infrastructures is an important area of application. A current project is the emergency power supply for the signal box of Deutsche Bahn in Sömmerda. In cooperation with the DB Bahnbau Group and DB Netz AG, the company has created a container solution for an uninterruptible power supply. For this purpose, the diesel generator, which had previously been responsible for the emergency power supply, was replaced by the emission-free fuel cell system HyModule S8 with an output of 7.8 kW.®
Hydrogen as an energy carrier with future potential
Fuel cells are building blocks for a sustainable energy supply. Due to the compact design of the stack module, these can be easily assembled into a higher-level system tailored to the respective application. If the hydrogen is then also produced via the electrolysis of water using renewable energies such as photovoltaics or wind energy, energy generation with fuel cells is CO2-neutral.
Diaphragm gas pumps from KNF ensure the controlled, continuous recirculation of hydrogen in the fuel cell stacks.
READ the latest news shaping the hydrogen market at Hydrogen Central
Electricity from hydrogen for infrastructure, April 4, 2023
