Biogas blending and flaring - instruments / controls

[marc29]

Anybody have any practical feedback/info on biogas flaring?
I'll be working on a biogas (CH4, CO2, H2S, O2) power generation unit.
If biogas routed to the stack, if calorific value too low (too low CH4 content), must be blended with LPG propane assist gas.

1) Instrumentation:
What are the different instrument/analyser possibilities? (performance, reliability, simplicity)
- full analyser multichannel (infrared/chemical) for CH4, CO2, O2, H2S?
- BTU analyser?
- simple CH4 sensor/detector?
- O2 needed for shutdown?
- H2S detection required?

2) Control:
What are the possible blending control philosophies?
- CH4 measurement on biogas inlet -> controller -> LPG valve
- BTU measurement on biogas inlet -> controller -> LPG valve
- CH4 measurement on blend -> controller -> LPG valve
- BTU measurement on blend -> controller -> LPG valve
- stack exhaust analyser -> controller -> LPG valve
- stack exhaust temp -> controller -> LPG valve

Many thanks.

 

[bimr]

You might contact Walker Process. They have been doing this for years. Walker Process is FM certified to make the fuel supply systems.

http://www.walker-process.com/prod_digestion_combinationBoilers.htm

 

[marc29]

Hi bimr,
Thanks a lot for the contact name.