Cyclone
Coarse particles are separated from the gas stream in a high efficiency cyclone separator. Entrained ashes from the gasifier are collected in an ash bin which can be opened at the bottom for regular cleaning.
Intermediate size particles and most of the fines are removed from the gasifier in an impingement separator of special design. This separator is insulated so as to avoid condensation of vapours and to allow passage of hot gas (above 150°C) to the glass fibre cloth filter.
5.1.4 Glass fibre cloth filter
To guard the engine against any solid material, the product gas is passed through a glass fibre cloth filter, which removes any solids that have slipped through the previous filter sections.
In order to maintain the temperature above the dew-point of the gas and to avoid condensation (approximately 80°C) this filter is also insulated with rockwool and an aluminium lining.
Both the impingement separator and glass fibre cloth filter are equipped with water gauge manometers in order to permit the continuous monitoring of pressure drop caused by fouling of the filtering devices.
Originally, the glass fibre cloth filter was equipped with a safety condensate outlet. In Giriulla it was found that such a device was unnecessary. Because some water was condensing in the connection pipe between cooler (see below) and engine air inlet manifold, the drain vessel was removed from the filter box and put in the connection pipe, where it worked better.
The cooling section consists of a tubular heat exchanger. Condensate can be tapped from the cooler by means of two drain vessels, equipped with safety taps, similar to the one described above. Cooler outlet temperatures vary between 30° and 50°C, depending on environmental conditions (temperature, wind) and engine load.