Investigation of the Use of Biogas in a Gas Hob

Abstract

The production of biogas from household and farm wastes is gaining in popularity, also with well-off users seeking to reduce their environmental impact or responding to rising energy prices and supply threats. Such users often own standard household gas appliances. Special biogas appliances are typically required because biogas has a low methane content compared to natural gas. It was hypothesized that unless modified, a standard gas hob could not operate on a gas that had the same composition as biogas. A standard gas hob was tested with a range of synthesized gas mixtures that represented biogas, as well as various levels of upgraded biogas. The tests consisted of measuring the time taken to heat one litre of water to 50 °C under various conditions in order to determine flame power and hob thermal efficiency, as well as determining the lowest methane composition required for ignition. The experimental work produced two main findings. The first was that increasing the injector size increased the heating rate of water and stove efficiency, and allowed for the ignition of a lower quality gas. Secondly, it was shown that upgraded biogas also improved the water heating rate and efficiency, and that a methane content of 80 % was considered a sufficient level of biogas upgrading in order to be compatible with a standard hob. It was thus shown that a standard gas hob could be modified in order to run on biogas, or that the biogas could be upgraded for use in an unmodified hob.