LNG Liquefaction

Faster Start-up Contributes to Quick Production Delivery

• Automated cool down of the Main Cryogenic Heat Exchanger (MCHE) using Modular Procedural Automation (MPA) shortens start-up time and avoids equipment damage

The MCHE is the key component of an LNG plant. It consists of large bundles of tubes in an aluminum shell. At start-up, the MCHE has to be cooled down from ambient temperature to around minus 160℃ where the natural gas is liquefied. Controlling the temperature of the MCHE according to the ideal temperature curve is challenging for the operator. Several valves need to be controlled at the same time while the process response changes as the cool-down progresses. Poor operation may result in exceeding the maximum allowable temperature change over time, which can damage the MCHE due to thermal expansion and contraction. However, slow cooling will delay the start of production. To avoid these risks, highly reliable and efficient automated operation is required. Yokogawa’s Modular Procedural Automation (MPA) employs the best operators experience, process expertise, analyses of the existing procedure and historical data. Automated cool down is enabled as if an experienced operator were controlling the plant. The start-up time is shortened without damaging MCHE.
 

Next-generation Advanced Process Control maximizes throughput

• Platform for advanced control and estimation optimizes production while ensuring stable control

The liquefaction process is complex because it is affected by factors, such as gas composition, ambient temperature, separator level and compressor performance. To achieve steady process control, those variables need to be controlled by Advanced Process Control (APC). Yokogawa has been providing APC licenses and consulting for more than 20 years. Based on our expertise in process automation, Yokogawa’s next-generation of APC, called Platform for Advanced Control and Estimation (PACE), provides process optimization to maximize throughput while ensuring steady process control.

Empower operations with Business KPIs to increase profits

• Profit-driven Operation enables integrated plant management

The business objectives of a manufacturing plant is to achieve the targets of Business KPIs (Key Performance Indicators) such as Safety, Productivity, Profitability, Energy saving(CSR), and Plant availability. Business KPIs are usually calculated using plant historian and reviewed by Plant Management on a monthly basis.
According to the market research, there are outstanding issues about Business KPI management, and it reduces plant profit.

・KPI disconnect between Plant management and Operators
・Partial KPI optimization due to silo
・Invisible KPI trade-off such as stability vs profitability
・Ex-post action to improve KPI

Yokogawa considered how to solve the above issues using Industrial Best Practices and Disruptive Digital Technologies. Profit-driven Operation (PDO) is a solution for process industries that drives seamless alignment with plant management objectives across the organization, from the plant floor through to the plant management, using the bridged KPIs. PDO helps Plant Engineers and Operators to solve their KPI issue before impacting to Business KPIs, calculating all KPIs in real-time using live DCS data.
Yokogawa has developed Industrial KPI templates for liquefaction and regasification plants and it helps PDO user to achieve early ROI by shortening engineering period. Karaoke dashboard is one of real time and ready-made KPI dashboard. This helps workforce to understand and control KPI trade-off like Japanese Karaoke system. Tree dashboard indicates the alarm conditions of each KPI in KPI tree structure. This helps operators and engineers to identify the root cause of KPI alarm and to solve KPI issue before impacting management KPIs. This also helps top management to understand what is happening on the plant floor.

Prepare for operational challenges with an advanced training simulator

• Plant simulator enables training of operations for every possible scenarios

Due to the shortage of experienced operators and engineers, human resource development has become a major management issue. Yokogawa’s Operator Training System(OTS) provides a virtual plant on a computer and realistic operations training such as plant start-up, shut-down, operation switching and emergency response.

We have a lineup of learning themes for each plant application, including C3MR and SMR models for LNG industry. OTS has been evaluated as a high fidelity plant simulator and are installed in all over the world.

At Oman LNG, OTS training is a major focus for operational efficiency.
Operators and trainers are required to deal with various scenarios such as emergency response and malfunction before being assigned to work at the actual plant.
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Video:Dynamic Plant Simulator at Oman LNG

Acid Gas removal

• Feed gas KO Drum pressure control
• Absorber Bottom Level/Flow control
• Absorber inlet lean amine flow control
• Pressure monitoring
• Temperature monitoring
• Treated gas quality monitoring
• Amine regeneration control
• Sulphur recovery unit control

Dehydration and mercury removal

• Drier sequence control
• Regeneration gas compressor control

NGL Recovery/Fractionations

• Feed Gas Pressure Control
• Bottom level and Disch. Flow control
• Reflux Flow control
• Reboiler temp control

Liquefaction

• Feed Gas Pressure/flow Control
• MR balance control
• Pre-cool refrigerant compressor and flow/temp control
• MR refrigerant flow/temp controls
• End Flash and pressure control
• LNG Rundown and Production control
• Anti-Surge Control

LNG Storage Loading

• Tank monitoring
• Loading sequence
• Circulation control for loading lines
• BOG compressor