Full-scale Experience with THIOPAQ® Technology from Paques - An Elegant Way to Desulphurise Biogas

European governments have increasingly recognised the fact that fossil fuels on earth are limited and that alternative energy sources need to be developed and implemented. Wind, sun and biomass are widely recognised as new sources of renewable energy.

Most countries have set ambitious targets for the development of alternative energy sources. Germany with its Feed-In Tariff Program is one of the front runners for stimulating sustainable energy development and use.
This programme is largely followed by Canada and USA and in addition to stimulating the production of bioethanol, the programme also promotes the usage of biogas and landfill gas for combined heat and power generation (CHP). Upgrading biogas to biomethane subsequently produces a vehicle fuel that is promoted in Sweden and this development is followed by South Korea.

Biogas is produced through the anaerobic digestion of wastewaters. The biogas produced by methanogenic communities contains methane ranging from 50 to 80v%, with the remainder being CO2 and H2O. Anaerobic lagoons and landfills are
the most simple and straightforward environments for biogas production, whereas digesters, UASB and IC reactors are the more advanced bioreactors. The produced biogas is collected and can be used as a source of sustainable green energy.
If sulphate, organic sulphur components and proteins are present, sulphate-reducing bacteria will compete with the methanogens for COD-usage.

In general the sulphate amount is much less than the COD content, almost all sulphate is reduced by the sulphate-reducing organisms to sulphide. The sulphide will appear in the biogas and its concentration can range from several ppm up to 3v%. Prior to use, the biogas for CHP requires H2S to be removed to prevent the production of acid rain and possibly more importantly to prevent corrosion and protect the oil in the engine from acidification. An efficient way to desulphurise biogas is the THIOPAQ® technology from water technology company Paques from the Netherlands.