Biogas leaks methane: confronting the challenge of process emissions: PRESENTATION
Cox, E., Assentech Sales Ltd, UK
(Free)
Huge leaks can be invisible to the human eye – This tank was next to a school
Mission – Reduce fugitive emissions from digesters
• Operating Pressure range <1 barg. Most <30mbarg
• Final emergency pressure relief from digesters
• Biogas used for electricity/gas generation
• Excess to flare
• Emergency relief via pressure/vacuum vent
• All valves should meet international standards API2000 or ISO28300
• No specific biogas standard. Application in process.
• Valve will begin to open from 75% of set point
• Many digesters run <90% of MAWP
• 9 out of 10 valve manufacturers do not test production vents according to section 5.4 (API2000) 6.4 (ISO28300)