Model predictive control
On a crude unit, one controller coordinates furnace outlet temperature, side-draw cuts, and overflash against tower pressure limits.
Industries / Refining
Refinery Advanced Process Control
Refinery advanced process control (APC) coordinates crude, vacuum, coker, reformer, FCC, and hydrotreating units so each runs closer to its limits at stable quality. Atlas Prediction Control restores and sustains APC performance inside the control systems you already run, from the first assessment to ongoing monitoring.
Request a Plant Performance Scan2 to 4 hours, remote, no cost.
Process Environments
Stable control performance across
complex refinery operations.
Refinery Applications
Where APC pays off in refining
Refinery units have interacting variables, changing feed conditions, and operating constraints. APC coordinates these variables to sustain performance.
| Unit | Interacting variables and limits | APC objective |
|---|---|---|
| Crude distillation | Furnace outlet temperature, side-draw cuts, overflash, tower pressure, crude switches | Maximize throughput and cut quality through feed changes |
| Vacuum distillation | Furnace temperature, vacuum level, wash oil rate, product draws | Maximize gas oil recovery within heater and tower limits |
| Delayed coker | Furnace coil temperature, drum cycle timing, fractionator draws, compressor limits | Push throughput and yield against heater and compressor constraints |
| Catalytic reformer | Reactor inlet temperatures, hydrogen to hydrocarbon ratio, octane | Hold octane at target with minimum giveaway, using quality estimation |
| FCC | Reactor temperature, regenerator limits, wet gas compressor, main fractionator | Maximize conversion at the active constraint |
| Hydrotreater and hydrocracker | Reactor temperatures, hydrogen supply, product sulfur | Hold sulfur spec while minimizing hydrogen and fuel use |
Operational Indicators
Signs a refinery unit is ready for APC
These operating conditions can indicate an opportunity to improve control performance.
Several variables interact, so moving
one loop disturbs others.
Response times are long, so operators
wait to see the effect of a move.
Product quality or safety limits cap
how hard the unit can be pushed.
Feed composition or rate changes often.
Energy-intensive equipment such as furnaces,
compressors, or reboilers sets the cost of operation.
Operating limits sit conservatively because
operators cannot see how close the unit is to them.
Crude switches push cut quality off target for hours.
A furnace, wet gas compressor, or fractionator
limit binds most of the time, and operators
hold margin by hand.
Engineering Capabilities
What Atlas delivers in refining
Engineering support covers the control models, underlying loops, operating constraints, and ongoing monitoring needed to sustain APC performance.
Quality estimation
A soft sensor infers reformate octane or product sulfur between lab samples, so control acts on a reading available every minute.
Advanced regulatory control
Feedforward from crude properties and decoupling on side-draw loops steady the base layer during a crude change.
Custom calculations
Calculated heater duty, tower flooding margin, or compressor surge margin give the controller a limit it can honor.
Monitoring and diagnostics
CLPM ranks loops by time in manual and valve health, and Atlas Advisor™, where deployed, ties APC and historian signals to root cause.
Lifecycle and performance services
Remote Resident™ rechecks models after catalyst changes, turnarounds, and crude slate shifts.
Working With Atlas
How an engagement works in refining
Assessment starts with the units where constraints bind most often and where operators hold the largest margins.
Assessment
A Plant Performance Scan (2 to 4 hours, remote, no cost) scores the unit. A Plant Audit (2 to 4 days onsite) adds a financial estimate. You provide engineer time and recent operating data. Atlas provides the score, findings, and loss estimate.
Step testing and modeling
Atlas designs and runs step tests in live operation, then builds or recalibrates the models. You provide operations access and test windows. Atlas provides test design, analysis, and models.
Commissioning
Atlas commissions the controller or soft sensor with your operators and validates it in live operation. You provide operator and engineering time and DCS integration support. Atlas provides tuning, validation, and handover.
Performance monitoring
Control Loop Performance Monitoring (CLPM) tracks loop and controller health against live data. A 90-day pilot on an agreed set of loops carries no fee.
Ongoing support
Remote Resident™ keeps models, constraints, and loops aligned as conditions change.
Technical Questions
Frequently asked questions
What is advanced process control (APC) on a crude unit?
APC on a crude unit is a multivariable controller
that moves furnace outlet temperature, side-draw
rates, and tower pressure together. It pushes
throughput and cut quality toward their limits
while honoring overflash, heater, and tower
constraints. Atlas Prediction Control restores
and sustains that controller so it keeps
working after commissioning.
How does APC handle crude switches?
A crude switch changes feed properties and
disturbs every cut. APC uses feedforward on
feed properties and quality estimates to start
moving before the cuts drift, while constraints
keep the furnace and tower inside limits.
Models need recalibration when the crude slate
changes, which is where Atlas starts.
How do you keep refinery controllers performing after commissioning?
Controllers drift as feeds, catalysts, and
equipment change. Atlas monitors loop and
controller health with CLPM, rechecks models
and inferentials against new lab results,
and reviews constraint limits on a set cadence
through Remote Resident™. The aim is to catch
widening limits and rising manual time before
they cost throughput.
Which refinery units benefit most from APC?
Units with interacting variables, binding
constraints, and quality targets benefit most:
crude and vacuum distillation, delayed cokers,
catalytic reformers, FCC, and hydrotreaters
or hydrocrackers. The best candidates run
against a heater, compressor, or fractionator
limit most of the time.
Does Atlas replace our existing APC or DCS?
No. Atlas is vendor-neutral and works inside
the control systems you already run, whether
commercial APC, licensor systems, or custom
controllers. Atlas restores model alignment,
tightens constraints, and builds baseline
control where none exists. It does not
replace DCS or APC infrastructure.
What does a Plant Performance Scan involve at a refinery?
The Scan is a 2 to 4 hour remote review at no cost.
Atlas interviews your process and control engineers,
views live DCS and APC behavior by screen share,
and pulls recent operating data. Within days
you receive a score out of 100, the key findings,
and an indicative annual loss figure.
Start With an Assessment
Find where refinery control performance is being lost.
Request a Plant Performance Scan. You receive a score out of 100, key findings, and an indicative annual loss figure.
Request a Plant Performance Scan2 to 4 hours, remote, no cost.