Refining chews through 6–8% of global industrial energy and energy can be up to half of a refinery’s operating cost. Senior engineers are squeezing that curve with advanced process control, heat integration, and cogeneration—often yielding double‑digit savings and short paybacks.
Refining is energy‑hungry by design. Crude processing alone accounts for 6–8% of global industrial energy, and energy expenses can comprise up to 50% of a refinery’s operating costs (Alfa Laval). Atmospheric and vacuum distillation (CDU/VDU—crude/vacuum distillation units) often use about 30% of a site’s energy, and optimizing these heat‑intensive steps—especially crude preheat trains—can cut that use by roughly 25% or more (Alfa Laval; DigitalRefining).
Benchmark data shows a performance gap worth chasing: world‑class refineries typically run ≥20% more efficiently, with Energy Intensity Index (EII—an industry energy benchmark) in the 60–80 range versus a 100 baseline (DigitalRefining).
The policy tailwind is real in Indonesia. State oil company Pertamina has publicly emphasized “optimizing oil refineries” to strengthen national energy resilience (Pertamina). Indonesian MEMR Regulation No. 14/2012 mandates that all major energy users (>6,000 toe/year) appoint energy managers, perform audits, and implement conservation measures—requirements any refinery must meet (IEA).
Energy benchmarks and regulatory context
At the unit level, CDU/VDU optimization is the primary lever because it dominates the fuel balance (≈30% of total), and improved heat recovery can trim that by ~25% or more (Alfa Laval; DigitalRefining). Closing that gap is not just a cost play; it supports compliance with Indonesia’s energy‑management law (IEA).
Multivariable APC for fuel and yield
Advanced Process Control (APC—multivariable predictive control with real‑time models and soft‑sensors) keeps processes at stable, constraint‑pushing setpoints. Typical gains include higher capacity, greater availability, reduced off‑spec yields, and lower energy cost (Control Engineering). In practice, controllers tighten furnace air‑fuel ratios (oxygen trim), minimize unnecessary distillation reflux or reboiler duty, and maintain tight furnace/fireplace controls—routines that are hard to coordinate manually (DigitalRefining; Control Engineering).
APC often pays back quickly: Yokogawa/Shell reported more than 250 installations by 2009, and refiners routinely use APC to “bring the setpoint closer to the operational limit” to conserve energy (Yokogawa; Control Engineering). Key functionalities include multivariable predictive control, inferential quality estimators, and constraint management. Case studies show APC can shave a few percent off energy intensity—tightening furnace O₂, for instance—with leading sites maintaining lowest‑quartile EII partly through these upgrades (DigitalRefining).
Implementation matters. Plant‑wide integration, selective “small vs. complex” loop design, clear ownership between engineers and operators, model maintenance, and planning/alignment were cited in lessons from Total’s Leuna refinery (DigitalRefining). APC will not alone cut energy by tens of percent, but it unlocks the stable operation other measures need. Industry surveys report ~1–3% net fuel savings when APC is executed with energy‑oriented objectives—a modest but cost‑effective gain given the low capital outlay relative to hardware (Yokogawa; Control Engineering). The bottom line: APC provides “low‑hanging fruit” by recovering human conservatism (DigitalRefining).
Pinch analysis and HEN retrofits
Process heat integration is the big lever. Pinch analysis (a method to define theoretical minimum heating/cooling and pinpoint “pinch” bottlenecks) and heat‑exchanger network design are standard tools to squeeze internal recovery (DigitalRefining; Ipieca). Industry cases show ≈20% or more utility savings versus earlier designs, with crude preheat retrofits directly reducing furnace duty (DigitalRefining).
Measures that recur: extending preheat trains by repiping to use hot effluents, side draws, and pump‑arounds (one Aramco study found the redesigned crude preheat network delivered the highest net present value), and upgrading to high‑efficiency welded‑plate exchangers to add transfer area within tight footprints (DigitalRefining; Alfa Laval). Plates can offer roughly 5× the area efficiency of shell‑and‑tube at high pressure/temperature (Alfa Laval).
Real‑world outcomes back the math: one refinery replaced four shell‑tube reboilers with a single plate exchanger, saving about 7 MW of continuous duty (~60 GWh/yr) and cutting 14.6 kt CO₂/yr (Alfa Laval). Globally, Alfa Laval estimates plate exchangers save refiners ~54 TWh/yr (≈245 million ton CO₂) compared with traditional designs (Alfa Laval).
Fouling control is part of sustaining any heat‑integration win. Some sites supplement cleaning programs with targeted chemistry; as an example, scale inhibitors are used in cooling and boiler circuits to manage deposition.
Steam networks and waste heat recovery
Optimized multi‑pressure steam (LP/MP/HP—low/medium/high pressure) with flash recovery reduces make‑steam costs. Redirecting high‑value steam to low‑pressure vents through turbines substitutes utility power, and recovering vented steam from drains/condensate keeps fuel demand down. APC‑enabled control of steam let‑down and flash trains is a critical enabler.
Supporting equipment fits naturally alongside trap and insulation work. A condensate polisher polishes steam condensate after heat‑exchange cooling, helping protect return loops. Accurate chemical feed to boilers is typically handled by an accurate dosing pump. Plants also deploy boiler oxygen scavengers to limit corrosion in steam systems.
Waste heat recovery adds another layer: older furnaces and hot vents often support waste‑heat boilers or gas‑to‑power (ORC/steam) additions. Focusing on major hot streams—furnace exhausts, regenerator flue—can often recover an extra 5–10% of energy. Published retrofits frequently show ≥20% total energy reduction from thorough heat integration; real‑world designs usually settle short of theoretical pinch targets to respect operability constraints. With high fuel prices, payback of 2–3 years is common; one analysis reported IRR ≈24% (NPV $21.8 million) on a heat‑train retrofit (DigitalRefining; DigitalRefining).
Cogeneration (CHP) configurations and economics
Power and steam are inseparable in refining. Conventional setups—buying grid electricity plus on‑site boilers—deliver roughly 50% combined efficiency. Cogeneration (CHP—producing electricity and then recovering residual heat for steam) typically reaches ~60–80% total efficiency (DigitalRefining). Ipieca reports CHP systems commonly achieve 50–70% electrical efficiency and consume 20–40% less fuel for the same power‑plus‑heat than separate generation (Ipieca; Ipieca).
Refineries often co‑fire natural gas or refinery off‑gas in gas turbines or engines, using heat‑recovery steam generators (HRSGs) to supply process steam and offset grid purchases. Sizing can enable surplus power sales. On‑site CHP also boosts resilience—studies note continued operation during grid outages (DigitalRefining). Recent economics are strong: designed properly, a refinery CHP retrofit can pay back in under one year (DigitalRefining).
Typical configurations include a gas turbine or reciprocating engine with HRSG, sometimes followed by a condensing/steam turbine—selected by capacity (from small 5–20 MW units up to tens of MW) and fuel. Case outcomes cited include 10–20 MW additions during turnarounds; one refinery reported tripling its thermal efficiency and cutting energy costs after installing a 12 MW CHP tract with expected payback under two years. Tail‑gas‑fired turbine engines (micro‑CHP) burning hydrogen‑rich waste gas have shown >70% fuel‑to‑energy efficiency. CHP directly lowers the carbon footprint per delivered energy and can “decouple” from grid emissions; renewable natural gas or hydrogen can further reduce carbon intensity.
Where CHP expands steam cycles, sites often update makeup‑water trains; engineers may specify RO, NF, and UF membrane systems to support boiler and HRSG water quality in industrial service.
Practical roadmap and expected outcomes
Roadmaps typically begin with an energy audit and benchmarking using indices like Solomon EII to pinpoint inefficiencies—CDU/VDU preheat and fuel‑network losses are frequent culprits. Sites define KPIs (e.g., MJ/bbl) and targets; many refineries aim for ≥15–20% reduction in fuel intensity over five years.
Control upgrades then lock in stability: APC on CDU, FCC (fluid catalytic cracker), reformer, sulfur recovery (SRU), and other key units using energy‑oriented objectives. Focusing on steady equipment such as heat exchangers, reactors, and furnaces and involving operators in tuning helps maintain gains; improvements show up as lower fuel rates at fixed throughput or better yield per unit energy.
Heat‑exchange retrofits follow pinch/HEN findings. Added exchangers capture pinch‑offset opportunities; low‑effectiveness units are replaced or augmented with high‑efficiency plates; more recovery is extracted from serial heaters, stripper condensers, and fractionation pump‑around networks. Typical incremental savings run 10–30% of firing fuel, with ROIs of 1–4 years depending on fuel prices.
Steam‑system optimization ensures traps, insulation, and condensate return are perfected; headers (LP/MP/HP) are re‑balanced; turbine‑driven pumps are considered where steam exergy fit is favorable. As a rule of thumb, each 1% reduction in steam venting or 1 °C lower cooling‑water return temperature translates to material fuel savings.
Cogeneration fills out the picture. Evaluations account for electricity price, gas price, incremental steam credit, and carbon factors. In many markets, a gas‑turbine plus HRSG can deliver 20–40% fuel savings versus separate heat and power, and current price spreads often yield projects whose NPV pays out in 1–3 years (Ipieca; DigitalRefining; DigitalRefining).
Put together, these measures often deliver double‑digit cuts in energy use. One China refinery cut CDU energy use by 30% via full optimization (Alfa Laval). An industry‑wide shift to compact exchangers could reduce global refinery energy demand by ~23% (Alfa Laval). The net result is lower fuel cost and lower carbon—impacting OPEX and aligning with Indonesia’s energy‑management rules (IEA).
Financially, portfolios bundling APC, pinch‑driven retrofits, and CHP commonly report IRRs exceeding 15–25%. One heat‑exchanger retrofit logged an NPV of $21.8 million and IRR ≈24% (DigitalRefining). Even “few‑percent” reductions matter at refinery scale—translating into multi‑million‑dollar annual savings.
