Biogas operators face increasing challenges in respect to the liquid manure ordinance, the liquid manure storage, the nutritional balance and the application of liquid digestate. Due to the reduced application times, a higher volume must be stored. A higher storage volume means high investment costs and, as the case may be, a reclassification in the Hazardous Incident Ordinance. Shorter application times result in even higher costs. All this is accompanied by soil compaction, way contamination, loss of nitrogen, provision of expensive application technology, additional workload and costs. An exhaust gas drying procedure is not only a very interesting economical solution, but considerably improves the overall situation of the plant and is active environmental protection. The exhaust gas flow contains 50% of the thermal waste heat of a BHPP. In most cases, it is discharged into the atmosphere via the exhaust gas pipe. With the exhaust gas flow of a BHPP, approximately 50% of the overall fermenter mass can be dried from e.g. 7% TS to 90% TS. This reduces the overall storage volume by 50% and simultaneously reduces the application.
Our exhaust gas drying is the ideal solution for these problems. There are 50% of the thermal energy of your BHPP in the exhaust gas flow. With this energy which is normally discharged unused via the exhaust pipe into the atmosphere, almost 50% of the liquid fermenter mass can be dried at a standard plant. While the liquid is completely evaporated, all nutrients remain in the dried digestate in a concentrated form. You have a valuable fertiliser for your own purposes or for marketing purposes.
During the drying procedure, the hot exhaust gases of your BHPP are fed into the material cloud of the dryer. Due to the high temperatures and the resulting thermodynamics, a kind of turbo drying procedure with an incomparable efficiency is achieved. The evaporation rate per litre of water amounts to approximately 750 W which is very close to ideal physical conditions. Liquid digestate is mixed to a moisture content of 70% via a drying return line and homogenisation screw and then transported into the dryer. Following a passage of less than 6 minutes, the humidity is reduced to a residual moisture content of 10% and leaves the dryer. Your digestate product is completely hygienised. Our dryers are acknowledged as a hygienisation stage. Thus, you have the option to market your dried digestate product as a fertiliser according to the fertiliser law.
The entire process is fully automated and is adjusted to varying outputs by means of an intelligent control. It does not matter if a smaller amount of gas is available at your BHPP or if it is operated via control energy in different power ranges, the dryer and the drying process are regulated in a fully automatic manner.
An ARC (active remote control) monitors the procedure in real-time and saves all drive, temperature and control-relevant data in an interval of 5 seconds. The supplied energy quantity as well as the throughput are measured and recorded for determining the cogeneration bonus.
Of course, we plan the project together with you. We prepare the required drawings and documents for a claim according to art. 15 or we provide the required documents including all expertises for an application according to art. 16.
We will be pleased to give you advice without obligation within the scope of a personal meeting.