Page last updated 30/08/2018
Small-scale Rural Biogas Programmes
Appendix Abstracts - 2
Appendix 4 Basic gas pipe fitting
The biogas from a biogas plant is only beneficial if it can be piped to where it is needed and used
efficiently. Gas leaks from piping are often a cause of operators deciding that their biogas plants are
not working. Biogas is being produced, but it is lost through the leaks. Biogas contains water
vapour, which can condense in pipes and block them, so measures need to be designed for the
water to be removed. As gas flows down a pipe, friction between the gas and the walls of the pipe
causes pressure losses, which can be calculated. (4 references).
Appendix 5 Gas appliance design
The design of biogas burners depends on the properties of biogas. The basic theory for the design of
biogas burners uses fluid flow theory and defines the sizes of key parameters, including the
diameters of the gas jet and the mixing tube throat. The total area of the flame ports is another
important dimension. Methods can be used to improve the stability of gas flames. (3 references).
Appendix 6 Follow-up surveys
Surveys are part of the work of follow-up, which is a key part of a biogas extension programme.
Surveys start with secondary sources: existing information on the survey area. Different types of
survey include inspection, questionnaires, group interviews, use of key respondents and field
measurements. Surveys must be carefully planned and then tested by using a pilot survey. (10
references).