A 4 t/h, 0.7 MPa gas-fired boiler priced between US $30 000 and US $60 000—and consuming 260–280 Nm³/h of natural gas—offers feed mills a turnkey solution for precise steam control, high efficiency and minimal emissions. Its advanced PLC control, comprehensive safety interlocks and compact design drive consistent pellet quality, reliable operation and optimized plant productivity.
Boiler Design and Performance
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Type: Horizontal, three-pass, wet-back fire-tube
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Capacity: 4 tonnes per hour (4 000 kg/h)
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Pressure: 0.7 MPa (7 bar)
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Steam Temperature: 150–170 °C (saturated)
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Thermal Efficiency: ≥ 98 %
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Flue-gas Exit Temperature: ≤ 60 °C
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Fuel Consumption: 260–280 Nm³/h of natural gas
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Package Price: US $30 000 – US $60 000
Compact and skid-mounted, this boiler integrates a fully automatic burner management system for rapid startups and smooth response to load swings.
Advanced PLC Control and Safety Features
A dedicated PLC platform continuously monitors and adjusts all critical parameters:
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Real-time Detection: Steam pressure, temperature, flue-gas O₂/CO, water-level probes
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Electronic Air-Fuel Ratio Control: Proportional valves fine-tune gas and combustion air for peak efficiency
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Scale Detection: ΔT and conductivity sensors trigger descaling alerts before fouling impacts performance
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Dry-Fire Protection: Low-water cutoff halts firing to prevent tube overheating
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Fault Alerts & Diagnostics: HMI/SCADA-driven alarms (on-screen, SMS or network) for flame failure, sensor drift, pump issues, etc.
Steam Quality
Direct injection of saturated steam ensures immediate condensation—ideal for mash conditioning. At 0.7 MPa, saturation temperature is about 165 °C (adjustable to process), promoting starch gelatinization and strong pellet bonding without the risks of superheat (uneven heat distribution or tube erosion). Dryness > 99 % prevents water hammer and carryover, safeguarding downstream equipment.
Integration and Upkeep
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Feedwater Treatment & Insulation: Proper deaeration, softening and header lagging
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Condensate Return: Preheats makeup water, reducing energy use
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Routine Maintenance: Tube cleaning, burner tuning, safety-valve testing
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Predictive Alerts: PLC-based maintenance reminders cut unplanned downtime
If you need a detailed quotation list, boiler solution, fuel cost estimate, boiler room design, please contact us and we will provide you with free service.
