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System Specifications
Oxygen injection system specifications for biological H2S removal in biogas applications. Dissolved oxygen injection rates, system sizing for 50-500 CFM capacity, HDPE distribution manifold design, monitoring parameters, and H2S reduction targets for flaring and RNG.
O2 injection system sizing by biogas flow capacity. Values are typical ranges for covered lagoon and anaerobic digester applications with biological desulfurization.
| Parameter | Small System | Medium System | Large System |
|---|---|---|---|
| Biogas Flow Range | 50-100 CFM | 100-250 CFM | 250-500 CFM |
| O2 Injection Capacity (Air) | 2.5-5.0 CFM | 5.0-12.5 CFM | 12.5-25.0 CFM |
| O2 Injection Capacity (Pure) | 0.5-1.0 CFM | 1.0-2.5 CFM | 2.5-5.0 CFM |
| Blower Motor Size | 1-2 HP | 3-5 HP | 7.5-15 HP |
| Distribution Header | 2" HDPE SDR 11 | 3-4" HDPE SDR 11 | 4-6" HDPE SDR 11 |
| Injection Points | 2-4 | 4-8 | 8-16 |
| Typical H2S Inlet | 500-2,000 ppm | 1,000-3,500 ppm | 2,000-5,000 ppm |
| H2S Removal Efficiency | 80-95% | 85-98% | 90-99% |
| Power Consumption | 1-3 kW | 3-8 kW | 8-20 kW |
| Estimated Capital Cost | $15K-$35K | $35K-$75K | $75K-$150K |
Values are typical ranges. Actual sizing depends on H2S concentration, removal target, biogas composition, and site-specific conditions. Contact EFI for project-specific engineering.
Required outlet H2S concentrations depend on the biogas end-use application. Biological O2 injection is typically the primary treatment; secondary polishing may be required for RNG pipeline specifications.
| Application | H2S Target | Rationale |
|---|---|---|
| Enclosed Flare | <200 ppm | Limits SO2 emissions to meet air permit thresholds; protects flare refractory lining |
| Open Flare (Candlestick) | <100 ppm | Incomplete combustion requires lower inlet H2S for SO2 compliance |
| RNG / Pipeline Injection | <4 ppm | Pipeline tariff specification (varies by utility); typically requires secondary polishing after biological treatment |
| RNG Upgrading Feed Gas | <50 ppm | Protects amine scrubbers and membrane systems from sulfur fouling |
| IC Engine / Generator | <100 ppm | Prevents accelerated wear of cylinder liners, valves, and exhaust components |
| Microturbine | <70 ppm | Turbine manufacturer warranty requirement; protects recuperator and turbine blades |
| Boiler / Direct Combustion | <250 ppm | Most tolerant application; limits depend on stack emissions requirements and boiler metallurgy |
Material specifications for O2 injection distribution systems in biogas environments. All materials must be compatible with H2S, moisture, and elemental sulfur deposits.
| Component | Material | Size | Pressure Rating | Notes |
|---|---|---|---|---|
| Main Distribution Header | HDPE SDR 11 | 2-6" diameter | 160 psi @ 73°F | Butt-fused joints; no threaded connections |
| Branch Injection Lines | HDPE SDR 11 | 0.5-2" diameter | 160 psi @ 73°F | Electrofusion or butt-fused couplings |
| Injection Nozzles | 316 Stainless Steel | 0.25-0.5" NPT | 150 psi | Check valve at each nozzle to prevent backflow |
| Air Supply Line | Schedule 80 PVC or HDPE | 2-4" diameter | 100-160 psi | From blower to distribution manifold |
| Condensate Drain Lines | Schedule 40 PVC | 1-2" diameter | Gravity flow | Drip legs at low points with manual or auto drain |
| Instrument Tubing | 316 Stainless Steel or PTFE | 0.25-0.5" OD tubing | 3,000+ psi (SS) | For analyzer sample lines; heat-traced if needed |
Required monitoring points for safe and effective O2 injection system operation. PLC/SCADA integration recommended for automated control and data logging.
| Parameter | Range | Measurement Method | Frequency | Alarm Setpoint |
|---|---|---|---|---|
| H2S Concentration (Inlet) | 0-10,000 ppm | Electrochemical sensor or GC | Continuous | >5,000 ppm |
| H2S Concentration (Outlet) | 0-1,000 ppm | Electrochemical sensor | Continuous | >200 ppm (flare) / >50 ppm (RNG) |
| O2 in Biogas Headspace | 0-10% | Paramagnetic or electrochemical | Continuous | >4% (warning) / >6% (shutdown) |
| Biogas Flow Rate | 0-600 CFM | Thermal mass flow meter | Continuous | <10% or >110% of design |
| O2 Injection Flow Rate | 0-30 CFM | Rotameter or mass flow | Continuous | >3% of biogas flow |
| Methane Concentration | 40-70% | NDIR or GC | Continuous or daily | <45% (dilution warning) |
| Biogas Temperature | 50-120°F | RTD or thermocouple | Continuous | >140°F |
| Blower Discharge Pressure | 0-15 psig | Pressure transducer | Continuous | >12 psig (high) / <2 psig (low) |
Get the complete O2 injection and H2S removal system specification sheet with sizing tables, pipe material schedules, monitoring parameters, and safety requirements in PDF format.
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