Refinery Process Fundamentals Curriculum
Module 7 - Utilities
Module from the Refinery Process Fundamentals Curriculum curriculum.
UTILITY SYSTEMS · Learning Objectives · 1. Describe refinery steam generation and distribution systems (BFW, boilers, steam headers) 2. Explain cooling water system operation and chemistry control 3. Understand instrument air and plant air supply requirements 4. Describe nitrogen generation and distribution for inerting and purging 5. Explain flare system design, operation, and environmental compliance · Refinery Steam System — Typical Pressure Levels
| Steam Level | Pressure (psig) | Temperature (°F) | Primary Uses | Generation Source | Consumption (typical % of total) |
|---|---|---|---|---|---|
| High Pressure (HP) | 600-900 | 750-900 | Turbine drives (compressors, pumps), process heating | Package boilers, waste heat recovery (FCCU, SRU) | 30-40% |
| Medium Pressure (MP) | 150-250 | 400-500 | Reboilers, ejectors, process stripping, turbine extraction | HP letdown, waste heat boilers | 25-35% |
| Low Pressure (LP) | 50-75 | 300-350 | Tracing, tank heating, deaerator pegging, strippers | MP letdown, process waste heat | 25-35% |
| Very Low Pressure (VLP) | 15-25 | 250-270 | Vacuum ejectors, tank heating, winterization | LP letdown, process condensate flash | 5-10% |
| Cooling Water System Parameters | |||||
| Parameter | Typical Range | Control Method | Purpose | Risk if Out of Range | Test Frequency |
| Supply Temperature | 85-95°F (summer) | Cooling tower fans, basin volume | Adequate heat removal from exchangers | High: reduced exchanger capacity, fouling | Continuous (online) |
| Return Temperature | 110-125°F | CW flow rate to exchangers | Limit biological growth, scaling | High: accelerated fouling, biological growth | Continuous (online) |
| pH | 7.0-8.5 | Acid/base injection | Control scale formation and corrosion | Low: corrosion; High: scale (CaCO3) | Daily |
| TDS | <2500 ppm | Blowdown rate (cycles of concentration) | Prevent excessive scale/fouling | High: scaling, deposits | Daily |
| Free Chlorine | 0.2-0.5 ppm | Chlorine/biocide injection | Biological control (algae, bacteria, Legionella) | Low: bio-fouling; High: corrosion of Cu alloys | 2x daily |
| Corrosion Rate | <3 mpy (mild steel) | Corrosion inhibitor injection, pH control | Protect piping and exchanger tubes | High: tube failures, leaks | Monthly (coupon) |
| Cycles of Concentration | 3-6 | Blowdown valve control | Balance water conservation vs. water quality | High: scaling; Low: water waste | Daily calculation |
| Source: FOS Chief Files — Module 14 (Hydrogen Plant), general utility system references, Cooling_Water_Chemistry_Log_v1.xlsx |
Source: Refinery_Process_Fundamentals_Curriculum_v1.xlsx · Sheet: Module 7 - Utilities
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