A front-end feasibility study (FEFS) and front-end engineering design (FEED) turn an outline biogas proposal into a firm design, cost and delivery time. For a 60 tonnes per hour palm oil mill, the proposed FEFS began with a ten-day sampling campaign and ended with a feasibility report. This post lists what each stage contains.
The challenge: committing capital on assumptions
Early quotations rely on the client’s data. Soil, topography and real effluent strength are often unknown, and the design cannot be fixed until they are. A staged approach avoids paying for the wrong plant.
Stage 1: FEFS
- A ten-day sampling campaign recording effluent flow, COD, total solids, temperature and pH.
- Confirmation of the biogas production rate.
- A topographical survey and a soil test at the proposed lagoon site.
- Finalising the electrical single-line diagram.
- Confirmation of configuration, scope, full capital cost and delivery time.
- A feasibility report.
Stage 2: FEED
- Overall heat, energy and mass balance.
- Process flow diagram, P&ID and general arrangement drawing.
- Detailed specification data sheets for components.
The plant that follows
- A cooling tower, mix tank with two submersible mixers and feed pumps, and a sludge sump.
- One covered reactor with actuated feed distribution, floating gas cover, liner, baffles, weir level control and an emergency vent.
- Two biogas blowers sized for 1,100 m³/h, an enclosed flare with at least 95% methane destruction, and PLC control.
- Dewatering and a 5-micron final filter (F9 class) before the engines.
Why it is worth the time
- Soil and groundwater affect lagoon depth and cost.
- Real COD can differ greatly from design figures.
- Electrical design fixes the connection to the powerhouse.
Tender documents from industrial owners often add a safety management system and a quality plan, so allow time for those.
What to consider
- Budget for the FEFS separately.
- Collect effluent data early.
- Ask for a clear scope and responsibility matrix.
- Time the programme with the rainy season.
FAQ
How long is the sampling?
Ten days in this proposal.
What is a P&ID?
A piping and instrumentation diagram.
Does FEED fix the price?
It confirms the full capital cost.
How long is delivery?
10 to 12 months from order.