In the far west of the republic on the Lower Rhine, only a few kilometres from the Dutch border, one of the first biogas plants that Envitec built for Karl Josef Heimes in 2003 is located in Kerken. Many greenhouses, which primarily grow flowers, characterise the rural region. Karl Josef Heimes, whose farm has 150 dairy cows and 100 head of cattle, was one of the first farmers in Germany to deal with biogas as a renewable energy. His location on Liebfrauenweg is virtually ideal, because right across the road, one of the region’s largest horticultural businesses grows balcony plants for the German idyll.
Flowers need warmth all year round, the resourceful farmer thinks. Heat that his Envitec biogas plant has in abundance. And so one of the first biogas plants in Germany already has an exemplary heat concept to this day. It would be desirable if more biogas plants had followed his example.
The biogas sector is still young in 2003. Good biogas engines that burn the lean gas efficiently and have good starting behaviour are not yet available on the market in a large selection. And so the prevented engineer Heimes decides to go among the engine builders himself and, together with a friend, develops an ignition jet cogeneration unit based on a Volvo Penta engine with 330 kW peak load. The engine is so successful that he sells no less than 20 of them in the following years to his new clientele, the horticultural businesses in the region.
As efficient as the engines are running, the disadvantage of the ignition jet operation is the high nitrogen oxide emissions. Heimes has an excellent knowledge of the combustion process and will find out about possibilities for exhaust gas aftertreatment and internal engine nitrogen oxide reduction as early as 2013. It was during this time that the first enquiry for an SCR system was made to the still young company Emission Partner. However, in 2013, they are still wavering off the idea that SCR exhaust aftertreatment is far too expensive and would never pay off for 330 kW. Instead, they recommend exhaust gas recirculation. However, it is precisely this enquiry from Kerken that shows the engineers from Ramsloh that there is obviously a market for SCR systems in the biogas business and that there are obviously no inexpensive solutions for the catalytic reduction of nitrogen oxides, especially in the segment below one megawatt electrical output.
Another 2 years later – Emission Partner has been operating an SCR prototype on a 105 kW 2G biogas engine in Friesoythe since the end of 2013 – Heimes again asks the catalyst specialists about the status of development. The tinkerer is determined to permanently comply with the nitrogen oxide limits of the TA Luft (German Clean Air Act) for his ignition steel engines with optimum fuel consumption. The pioneers on both sides will soon come to an agreement. The first SCR system will be put into operation on a Volvo Penta TAD1641 GE jet-ignition engine from Heimes in July 2016. Another three SCR systems are to follow in the next six months. One of them will also be mounted on his jet engine, which is located on the Envitec biogas plant.
And here again, Mr. Heimes, the tinkerer and biogas pioneer, is one of the first in Germany to continuously reduce the nitrogen oxide emissions of his biogas CHPs using SCR technology.