Views: 0 Author: Site Editor Publish Time: 2025-09-01 Origin: Site
Dry Air Cooler with Auxiliaries & Associated Facilities for Southeast Asian Gas Fields
A Dry Air Cooler is a critical heat rejection device for gas field operations, using ambient air (instead of water) to cool process fluids (e.g., natural gas, lube oil, or compression interstage fluids). In Southeast Asia—characterized by high temperatures (25–35°C year-round), high humidity (60–90%), and frequent monsoons—DAC systems require specialized design, auxiliaries, and infrastructure to ensure reliable performance.
In Southeast Asian gas fields (e.g., offshore platforms in Indonesia, onshore fields in Malaysia, or pipeline stations in Thailand), DACs primarily serve two critical roles:
Process Fluid Cooling: Cool high-temperature natural gas after compression (gas compressors generate heat, raising gas temp to 80–120°C; DACs reduce it to 40–50°C for downstream processing, e.g., dehydration or liquefaction).
Auxiliary Equipment Cooling: Maintain safe temperatures for rotating machinery (e.g., compressor lube oil, engine jacket water) and electrical systems (e.g., transformer oil), preventing overheating in the region’s hot, humid climate.
| Component | Design Details & Regional Adaptations |
|---|---|
| Heat Exchanger Coil | The core heat transfer element, typically a fin tube coil (maximizes air contact area): - Tube Material: Carbon steel (for non-corrosive fluids like lube oil) or 316L stainless steel (for corrosive fluids like natural gas with H₂S, common in Southeast Asian gas fields). - Fin Material: Aluminum (lightweight, high thermal conductivity) with epoxy coating (resists corrosion from humid air and monsoon salt spray). - Fin Density: 10–15 fins per inch (higher density = more heat transfer, but requires anti-fouling measures to prevent dust/debris buildup during dry seasons). |
| Air Fans | Drives ambient air across the coil; designed for high humidity and variable wind: - Type: Axial fans (high airflow, low pressure drop, ideal for gas field DACs). - Motor: Totally Enclosed Fan Cooled (TEFC) motors (IP55/IP65 rating) to prevent humidity, dust, or rainwater ingress. - Speed Control: Variable Frequency Drives (VFDs) to adjust airflow based on ambient temp (reduces energy use during cooler monsoon months). |
| Fan Casing & Shrouds | - Material: Galvanized steel or fiberglass-reinforced plastic (FRP) (resists rust from monsoon rains). - Wind Deflectors: Added to the fan inlet/outlet to counter Southeast Asia’s strong seasonal winds (prevents airflow reversal, which reduces cooling efficiency). |
| Support Structure | - Elevation: Raised 1.5–2 m above ground (avoids flooding during monsoons, common in low-lying onshore gas fields). - Material: Hot-dip galvanized steel (resists corrosion from humid soil and salt air in coastal fields). |
| Auxiliary System | Purpose & Regional Design |
|---|---|
| Anti-Fouling System | Prevents buildup of dust, pollen, or agricultural debris (common in rural Southeast Asian fields) on coil fins: - Type: High-pressure water spray nozzles (connected to a dedicated freshwater tank—avoids saltwater corrosion) or compressed air blowers. - Automation: Timed cleaning cycles (1–2x per week during dry seasons, adjusted via PLC) to avoid manual intervention in remote locations. |
| Dehumidification & Drainage | Mitigates condensation (high humidity causes water buildup on coils, which can freeze in rare cool spells or promote corrosion): - Condensate Drains: Sloped coil design + automated float drains (prevents water pooling). - Heated Coil Headers: Optional electric heaters (for high-humidity offshore platforms) to keep coil inlets/outlets above dew point (15–20°C). |
| Fire Protection System | Gas fields are high-fire-risk environments; DACs (with electrical fans/motors) require: - Sprinkler System: Water mist sprinklers mounted above the DAC (connected to the gas field’s fire water network). - Flame Detectors: UV/IR detectors linked to the field’s emergency shutdown (ESD) system (triggers fan shutdown and sprinklers if fire is detected). |
| Power Backup | Southeast Asia has frequent power outages (especially in remote fields); ensures DAC operation during blackouts: - Diesel Generators: 100% capacity backup (sized to power the DAC and its auxiliaries) with auto-start (activates within 10 seconds of power loss). - Battery Backup: For critical controls (PLC, VFDs) to prevent system damage during shutdowns. |
| Instrumentation & Control | Monitors performance and adapts to variable climate: - Sensors: Ambient temp/humidity sensors, fluid inlet/outlet temp sensors, fan vibration sensors, and differential pressure sensors (detect fin fouling). - PLC & SCADA Integration: Centralized control (linked to the gas field’s SCADA system) for remote monitoring/operation (critical for unmanned offshore platforms). - Alarm System: Alerts for high fluid temp, fan failure, or low water (for anti-fouling sprays) via SMS/email to on-site or off-site operators. |
