PuK - Process Technology & Components 2022

Leading article Hydrogen

Leading article Hydrogen structure coupling with LOHC as storage medium Prof. Dr.-Ing. Eberhard Schlücker If a country wants to go into the future with hydrogen and thus secure the energy supply, synergetic solutions are required that raise the overall efficiency of hydrogen use to a maximum level. While in last year’s edition of the PuK the example of a sewage treatment plant as an energy centre showed a complete synergetic approach for decentralised structures, we are now listing other examples on a small to large scale, which can be exemplary for centralised but also decentralized structures. fits in with the heating oil infrastructure. This property allows us to think freely. Example residential buildings If someone has PV of sufficient size (10 KWp is already sufficient in summer in Germany. In more southern countries the energy yield is even greater and less is enough) on his house roof and has the usual 10–14 KWh per day consumption and one can assume 8 hours of sun (sunny day), then the ficiency in energy matters. However, if you want to produce and store hydrogen at home, you need an electrolytic cell and a hydrogenation system. There will be so little hydrogen between these two components that there will be no danger, and absolutely airtight components would be used for this purpose. The waste heat from the two components can be used for hot water, cooking (new form of cooking with steam), etc. in the summer. In the transitional periods, the heating is added. If this house now District heating of the companies from local data centre Waste wood, sewage sludge, residues Exhaust gas CO 2 H 2 Reactor Methane Water Tank H 2 gas Elektrolysis Electric current O 2 Q H 2 Q Oven Steam Q Salt storage with integrated reactor Q Catering company Hydrogenation reactor LOHC Steam H 2 LOHC H 2 H 2 Petrol station Tank LOHC Fuel cell Petrol station Water for electrolysis Electricity Energy logistics centre flow diagram. Red areas: products; red arrows: hot streams, gas, steam, hydrogen; yellow: LOHC area; green: power generation. The prerequisites for these considerations are that the LOHC based on dibenzenetoluene or benzyltoluene is absolutely non-flammable even when charged with hydrogen and can therefore be transported by anyone, for example in buckets or plastic canisters, but can also be pumped without any problems. It is therefore easy to use even for laypersons and private electric car can be charged additionally and still energy would be left, which one could save for the winter instead of feeding it into the grid for a fraction of the cost, which one pays for electricity oneself. Since energy prices are expected to continue to rise, the population will certainly strive to develop a certain degree of independence and self-sufhas an SOFC fuel cell that can also be used as an electrolysis cell (twoway operation), then the waste heat from the SOFC fuel cell (waste heat temperature approx. 800 °C) could be sufficient for dehydrogenating the hydrogen from the LOHC, which is then converted into electricity in the SOFC to supply the house. The heating energy for the residential building 10 PROCESS TECHNOLOGY & COMPONENTS 2022

Leading article would be included here (note: such a fuel cell is currently being developed (patented)). This means that a residential building could be self-sufficiently supplied all year round. As far as is known, this SOFC is being developed for four houses at once or for multi-family houses. Other models are also conceivable that combine several houses into energy units or cooperate with small businesses. In addition, however, homeowners could install even more PV on their house roof and thus become energy suppliers who could also supply LOHC or the centres or also produce electricity at home and feed it into the grid in times of shortage. Urban areas – energy logistic centres Cities and industrial areas don’t have it that easy. Of course you are supplied by energy suppliers (e. g. in Germany also by imports), but you can also produce a lot of energy yourself using PV. In this way, all roofs, but also parking lots, can be covered with PV. But if you pursue synergetic approaches, then even more is possible. A project that is currently being worked on in the preliminary planning is an energy logistics centre (Fig. 1). This is to be built in the centre of an industrial area. About 1 square kilo metre industrial roof area is available there to be covered with PV. There is also a parking area of about 0.5 km 2 that could have a roof put over it which could be also covered with PV. There is also a large data centre that produces a lot of waste heat and therefore has a high power requirement. Since a large proportion of the industrial buildings are warehouses and, with the exception of the data centre, there is no highperformance industry, the electricity that can be generated with PV should be almost sufficient. A nearby wind power plant can fill the gap that still exists, or small wind power plants can be retrofitted on the high company roofs. However, a storage concept is necessary for a certain self-sufficient supply throughout the year in order to be able to shift the excess electricity from day to night, from sunny days to rainy days and also from summer to winter. A catering company that supplies ready-to-eat meals is located in the vicinity of the building site for the energy logistics centre. On the other side is a bus company that is converting to hydrogen propulsion technology. The catering company cooks with steam. So the logistics centre is equipped with electrolysis cells and the hydrogen is stored in LOHC. The waste heat from the reactors and cells is used to generate steam and is used to supply the neighbouring company. Since cooking is preferred during the day, the required power density is limited to around 10 hours. Nevertheless, this heat is still not enough. Therefore, an additional natural material incineration plant for waste wood or sewage sludge is being built on this site, which works with pure oxygen from the electrolysis cell. Pure We tackle the challenges of the future – with our intelligent vacuum solutions. www.buschvacuum.com