Model predictive control (MPC)
On a liquefaction train, one controller coordinates refrigerant composition, compressor loading, and feed gas rate against compressor and driver limits.
LNG and Gas Processing Advanced Process Control
LNG advanced process control (APC) coordinates liquefaction trains, NGL fractionation, acid gas removal, and dehydration to maximize throughput within compressor and driver limits. Atlas Prediction Control restores and sustains APC performance inside the control systems you already run, through ambient and feed gas swings.
Request a Plant Performance ScanGas processing and LNG
LNG and Gas Processing Advanced Process Control
Where APC pays off in gas processing and LNG
| Unit | Interacting variables and limits | APC objective |
|---|---|---|
| Liquefaction trains | Refrigerant composition, compressor limits, ambient temperature, feed gas rate | Maximize LNG production within compressor and driver limits |
| NGL fractionation | Deethanizer and demethanizer pressures, reflux, product purity | Maximize liquids recovery at spec |
| Acid gas removal (amine) | Solvent circulation, regenerator duty, CO2 and H2S limits | Hold treated gas spec with minimum reboiler energy |
| Dehydration | Regeneration temperature, water dew point | Stable dew point with lower energy |
| Fuel gas and utility systems | Header pressure, demand swings | Smooth fuel supply to heaters and turbines |
Signs a gas processing or LNG unit is ready for APC.
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.
Production falls on hot days because compressor or driver limits bind.
Feed gas composition and rate swing, and operators detune controllers to stay safe.
What Atlas delivers in gas processing and LNG
Quality estimation (soft sensors)
A soft sensor infers NGL product composition or treated gas CO2 between analyzer readings.
Advanced regulatory control (ARC)
Ratio and cascade control hold refrigerant composition and dehydration regeneration temperature steady.
Custom calculations
Ambient-corrected driver power limits and compressor operating point calculations give the controller limits that move with the weather.
Monitoring and diagnostics
CLPM ranks loops by time in manual, oscillation, and valve health. Atlas Advisor™, where deployed, ties APC and historian signals to root cause.
Lifecycle and performance services
Remote Resident™ rechecks models and limits across seasons and after feed changes.
How an engagement works in gas processing and LNG.
assessment looks at how often compressor and driver limits bind across seasons, and at how far operators detune controllers during feed swings.
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.
Frequently asked questions
How does APC increase LNG train throughput?
APC coordinates refrigerant composition, compressor loading, and feed gas rate to hold the train at its active constraint, usually compressor or driver power. It reacts to ambient temperature and feed changes within limits. Atlas restores the models and constraint limits that let the controller keep the train there.
How does ambient temperature affect liquefaction control?
Higher ambient temperature reduces cooling and driver capability. A train with spare capacity on a cold night can hit compressor or driver limits in the afternoon. A controller with ambient-aware limits and a current model adjusts feed and refrigerant to stay at the constraint.
What does APC do in a gas plant?
In a gas plant, APC controls NGL fractionation pressures, reflux, and purity, holds treated gas specifications in amine units with minimum reboiler energy, and stabilizes dehydration dew point. The aim is liquids recovery and stable specification at lower energy.
Which gas processing and LNG units benefit most from APC?
Liquefaction trains, NGL fractionation, acid gas removal, dehydration, and fuel gas systems. Each has interacting variables and an active constraint that shifts with feed and ambient conditions.
How do you keep gas plant controllers performing?
Atlas monitors loops with CLPM, rechecks models after feed or equipment changes, and reviews limits that have widened. Remote Resident™ keeps this work on a regular cadence, so drift is caught before it costs throughput.
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. It does not replace DCS or APC infrastructure.
LNG and Gas Processing Advanced Process Control
LNG advanced process control (APC) coordinates liquefaction trains, NGL fractionation, acid gas removal, and dehydration to maximize throughput within compressor and driver limits. Atlas Prediction Control restores and sustains APC performance inside the control systems you already run, through ambient and feed gas swings.
Request a Plant Performance Scan