The elevated flare essentially consists of a burner, installed on the top by a selfsupporting structure, with a protection windscreen, a pilot equipped with an high energy ignitor and a flame detection system control thermocoulple type.
The flare ignition is of automatic type, controlled by an electrical panelboard generally mounted at the flare ground, in explosion-proof execution, and regulated by an ON-OFF electric valve mounted on the biogas access pipes.
The lack of a combustion chamber with refractory insulation and the free flame combustion make that either the biogas mixture with the necessary air for combustion or the combustion temperature are hardly checkable. This type of flare produces a luminous flame which can be seen over the windbreak.
The height of these flares, being free flame type, is determined by the radiations which the heat produced by the combustion transmits at ground level, and depends on the amount and on the features of biogas to be swallowed. Therefore the height of these flares, which are calculated according to international standards, is such as to ensure a sufficient protection to the people and the things possibly you have ground level.
However the simplicity of the elevated flares makes it impossible to answer to the standards of emission which are at present applied in most developed countries. The absence of a covering together with the intense heat produced to the top of the elevated flares make a very difficult emission monitoring.
Historically the free flame flares have become popular for their simplicity and their low cost, taking into consideration the absence of parameters and combustion gas checks. They are particularly used where the biogas to be burnt is discontinuous and where no emission check kind is required by the competent authorities.