1. The Brazilian biogas and biomethane market in 2026
Brazil has a structurally privileged position for biogas: robust agricultural matrix generating organic residues at scale (sugarcane vinasse, swine and bovine waste, poultry residues), urbanization generating landfills with recoverable biogas, and animal protein industries with capturable treatment lagoons. The Renovabio program (Law 13,576/2017) created the CBios (Decarbonization Credit) market that monetizes carbon reduction via biofuels, including biomethane.
ANP 8/2015 regulation set technical specifications for biomethane injection into the natural gas grid — opening the way for biogas plants to produce vehicular or industrial fuel.
2. The three flows of a biogas plant — separating the problem
The first engineering rule in a biogas plant is to separate the three flows with completely distinct physical requirements — assuming "it's all organic fluid" leads to wrong specifications and prematurely worn pumps.
- Flow 1 (raw abrasive): raw landfill leachate, digestate with coarse fiber, primary sludge — requires pump that tolerates abrasive solids and fibers (progressing cavity, lobe or slurry centrifugal)
- Flow 2 (clarified viscous): leachate after pretreatment (sieved/sedimented), clarified digestate, biofertilizer after decanter — H2S-resistant FBE gear pump is suitable
- Flow 3 (clean process liquids): biomethane in scrubber (amine water or pressurized), wash water, methanol recovery from biodiesel route — standard FBCN centrifugal in sour service serves
3. FBE on flow 2: clarified leachate and digestate
Clarified landfill leachate (after rotary sieve and sedimentation tank) and clarified anaerobic digestate (after decanter or centrifugation) have moderate viscosity (50-500 SSU depending on organic matter content), are oily fluids with average lubricity, and contain dissolved H2S in concentrations between 100 ppm and 5,000 ppm depending on the substrate. For this fluid, the FBE external gear pump is a good choice — provided materials are selected for sour service.
The standard recommended material is 316L stainless steel (CF8M) with HRC 22 max hardness limit per NACE MR0175 / ISO 15156 to resist sulfide stress cracking. For H2S above 3,000 ppm or low pH (<5), we recommend duplex 2205 steel () which offers additional resistance to pitting and crevice corrosion. Sealing is via type 21 mechanical seal with tungsten carbide face (do not use carbon in H2S fluids because carbon is attacked).
4. FBCN on process utilities: scrubber water and recovery
Purification of raw biogas (60-65% CH4, 35-40% CO2, H2S traces and moisture) to biomethane (95-98% CH4) typically uses solvent scrubber — pressurized water for CO2 removal or amine (MEA or DEA) for more efficient removal. Scrubber circulation pumps operate with clean fluid at moderate residual H2S content, medium flows (10-200 m³/h) and moderate pressure (5-15 bar). FBCN serves this application — normalized centrifugal with 316L or Duplex internals per H2S concentration.
5. FBOT in digester heating — cold climates and purification
Anaerobic digesters typically operate between 35-40°C (mesophilic) or 50-55°C (thermophilic). In cold climates in southern Brazil or in operations continuously above mesophilic, a heating system is required — thermal oil boiler or steam boiler with exchangers. The thermal oil circuit operates at 150-250°C and uses an FBOT pump (thermally isolated centrifugal). Additionally, biomethane purification plants may use thermal oil for amine regeneration (stripper) — another classic FBOT application.
6. By-products of the integrated biodiesel-biogas route (glycerin, BPF)
Integrated biodiesel + biogas plants generate by-products with their own flows. Crude glycerin — transesterification co-product — can go to sale as chemical feedstock or back to the digester as substrate. Glycerin has viscosity between 900 and 3,000 SSU at 40°C — ideal fluid for FBE (external gear). BPF, when produced at the plant from heavy crude oils, requires heated transfer at 70-100°C with FBE in standard material (ASTM A48 cast iron if no H2S, 316L if present).
7. Where we are NOT the best choice — raw abrasive flows
Technical honesty is fundamental in biogas because the sector is in collective learning phase in Brazil — many projects suffered from misspecified pumps on flow 1 (raw abrasive). FB Bombas' FBE gear is NOT the appropriate technology for raw leachate (with straw, plastic, particles), raw digestate with coarse fiber, or primary sludge with solids above 5% by mass. For these flows, we recommend progressing cavity or lobe technologies, supplied by global specialists.
- Netzsch (German): NEMO progressing cavity pumps and Tornado lobe pumps — global reference in leachate and abrasive digestate
- Boerger (German): ELRO and PUMPI Boerger lobe pumps — specialized in fluids with solids and fibers
- Vogelsang (German): VX and IQ rotary lobe pumps — used worldwide in agricultural biogas
- SEEPEX (German): BN, MD, and SCT progressing cavity pumps — also a reference in abrasive sludge
8. Selection table by application in biogas-biomethane chain
The table crosses typical pumping points of the chain with the recommended technology — FB Bombas where we are adequate, global specialist where we are not.
| Pumping point | Fluid characteristic | Recommendation |
|---|---|---|
| Raw landfill leachate extraction | Abrasive solids + plastic + sand | Netzsch / Boerger / SEEPEX (not FB) |
| Raw agricultural digester digestate | Coarse fiber + solids 5-10% | Netzsch / Vogelsang (not FB) |
| Clarified leachate post pretreatment | 50-500 SSU, H2S 100-3,000 ppm | FBE 316L sour service |
| Clarified digestate post decanter | 100-300 SSU, residual H2S | FBE 316L |
| Liquid biofertilizer distribution | 50-200 SSU post-clarification | FBE or FBCN (per viscosity) |
| Scrubber water in purification | Water or amine + residual H2S | FBCN 316L or Duplex |
| Crude glycerin from biodiesel route | 900-3,000 SSU at 40°C | Standard FBE |
| Thermal oil digester heating | Therminol 150-250°C | FBOT |
9. Renovabio, ANP 8/2015 and ABNT NBR 13971 safety compliance
Plants intending to generate CBios via Renovabio must demonstrate carbon reduction via Rota Renovabio — lifecycle audit certified by independent firms. This impacts pump specification indirectly: equipment with lower energy OPEX (correct BEP, documented hydraulic efficiency) enters the carbon balance better. Plants injecting biomethane into the natural gas grid must meet ANP 8/2015 (minimum CH4 composition, maximum H2S, maximum CO2, dew point).
The pump does not directly impact this composition, but purification scrubber pumps are part of the chain that enables meeting the specification. The Brazilian safety standard applicable to biogas handling is ABNT NBR 13971 — electrical equipment in classified-risk areas must be ATEX/INMETRO certified.
