Compressed Bio Gas Plant Mechanical Engineering

I’m putting together a full design package for a green-field biogas facility that will process more than 50 t/day of Napier grass (or similar energy crops) and upgrade the gas to >90 % pure Bio-CNG. To move from concept to construction I need a process engineer—or a small interdisciplinary team—to translate my production targets into a fully engineered solution that can be handed straight to EPC contractors and automation vendors. The scope begins with the biology. I will supply rough feed analyses; you will calculate the organic loading rate, hydraulic retention time, expected gas yield, nutrient balance, and mixing power for a continuously stirred tank reactor (CSTR) train. From those figures we’ll finalise digester volume, agitation duty, heating loops, and any necessary feed pre-treatment. Once the raw biogas numbers are set, the job expands into purification. Please size and specify an economical PSA, water-scrubbing, or membrane system—your choice, so long as it consistently strips CO₂, H₂S, and moisture to reach the 90 % + methane spec. Utility demands, media consumption, and expected skid footprints have to be part of the package. Mechanical and instrumentation detail is essential. I need complete PFDs and P&IDs, line lists, datasheets for slurry pumps, heat exchangers, flare, blowers, flow meters, analysers, and safety valves. Every piece should close out a mass- and energy-balance so the numbers reconcile. Because the plant will run largely unattended, a high-level PLC/SCADA narrative is also required. Describe temperature control loops, pH and pressure interlocks, emergency shutdown logic, and the commissioning sequence needed to start the biology safely the first time. Deliverables (all native files plus PDFs): • Block flow diagram, PFD, heat & material balance • P&IDs with annotated equipment and instrument tags • Equipment sizing calculations and datasheets • Gas upgrading package sizing and vendor recommendations • Control philosophy and PLC/SCADA I/O list • Commissioning and biological start-up plan Drawings can be produced in AutoCAD P&ID or similar; calculations in Excel, ASPEN, or your preferred process software, as long as assumptions are transparent. If you’ve taken at least one large-scale digester from design through commissioning, especially with fibrous energy crops, I’d like to see that experience reflected in your proposal along with a rough timeline to first draft.