COMPACT DESIGNED "BIOGAS" DRYERS TO REMOVE WATER, DUST PARTICLES AND POSSIBLY SULPHUR FOR COMBINED CYCLE INSTALLATIONS UP-TO 1000 M3/HOUR TO INCREASING THE RELIABILITY OF THE GAS ENGINE OR STEAM TURBINE

Stricter environmental regulations enforce a development in the use of alternative energy sources. One of these energy sources is biogas from waste treatment installations, to replace the use of fossil fuels.

History:
The market for biogas fired (combined cycle) installations is therefore growing rapidly. Raw biogas has to be purified however before it can be used. Operators of Biogas installations and manufactures of gas engines are experiencing, that for most "Biogas" installations, removal of water, dust particles and sulphur is crucial for a proper performance of the engine, without much maintenance and down time.

Solution:
Geurts International a leading company with over 40 years of experience in the heat exchanger technology, and well known for its creativity on designing and developing new technology has developed a compact biogas drying system to remove water, dust and sulphur from the produced “Biogas”.

A very compact vertical Biogas drying system was designed, combining the removal of water, dust and sulphur, in one installation. This biogas conditioner is based on direct contact between biogas and scrubber fluid, which contact is established through a packed column. The scrubber fluid is cooled over an integrated plate type heat exchanger below 5° C before entering the top of the column. The water in the biogas (Relative humidity of 100%) will condense when contacting with the surface of the packing material. The condensate and scrubber fluid will be collected in the circulation tank underneath the column. The surplus of fluid will be drained out of the tank. In order to neutralize the absorbed sulphur NAOH will be added to the scrubber fluid.

The treated biogas passes a demister to remove droplets and is heated up by an integrated gas / gas heat exchanger at the top of the column or by a separate heater fed with the engine cooling water of +/-90 °C
The removal efficiency of this type of installations for sulphur and dust is around 90 %, the relative humidity of the biogas is reduced from 100 % to 60%. As a result the reliability of the gas engine or steam turbine can be increased considerably. Consequently down time and maintenance cost can be significantly reduced.