Four ways to improve midstream process optimization
Boost output and use fewer resources while increasing plant life and performance.
The prevailing oil price slump has left everyone shaken, be it independent shale producers with a few rigs in their backyards or oil and gas giants who have dominated the market for years. The one thing that many have come to appreciate is the potential value of optimization.
When selling prices get close to operating costs, any effort to shave off an extra dollar is rewarded. While this is true for the upstream, there is a lot of incentive for midstream and downstream facilities to follow suit. Process optimization is one of the least capital-intensive methods of improving margins and is ideal for prolonged slumps where stakeholders and managers rarely see eye to eye.
What is process optimization?
Process optimization is a systematic improvement to all aspects of an operational process in order to improve output, utilize fewer resources and increase plant life and performance. Its implementation can vary from the slightest changes in inlet temperature, operating temperature or reagent concentrations to redesigning entire processes to improve utilization and yields. There are four main areas where midstream process optimization can be implemented:
- The initial process
- Process parameters and operating constraints
- Equipment, instruments, and devices associated with the process
- Personnel tasked with oversight/operation of the process.
Optimize the initial process
Optimization encompasses redesigning or revising the process to uncover hidden efficiencies or rectify design inefficiencies. While most modern plants and facilities are extremely unlikely to have design inefficiencies, sometimes factors like changes in demand and expansion can render the original process inefficient. For example, a compressor station operating at peak efficiency with three compressors found maintenance costs increased when gas demand was significantly lowered. The operator redesigned how often each compressor worked to improve uptime under a lower load, reducing maintenance costs.
In another example, managers at a gas plant reused excess flare gas by redirecting it to generator sets that powered the plant’s residential units. Electricity overhead was reduced while increasing the efficient use of flare gas.
Optimize process parameters and constraints
Operators at aging facilities can feel overwhelmed with alarms. As a plant ages, its instruments lose accuracy, control valves and rotating equipment wear out, pipes corrode, and electronics start failing. Optimizing process parameters and constraints covers analyzing the process with respect to its plant’s condition and revising its parameters to make the best use of what the plant has to offer. Managing equipment load and times, adjusting pressures, temperatures, and reassessing the amount of reagents go a long way in improving midstream process output and reliability. A healthy alarm management system can reduce the load on operators and prevent unwanted process hindrances.
These activities are highly recommended for gas processing and liquid natural gas (LNG) plants. Similar results can be achieved with pipelines, compressor/pumping stations, tank farms, and valve stations. For example, if a particular gathering station has wetter gas than normal, applying corrosion and drag-reducing agents can prolong pipeline life. If the station also has a separator and/or sweetener, they will require revised parameters too.
Equipment, instruments, and devices used in the process
The equipment’s age may also be an issue. Sensors lose sensitivity over time, control valves get rigid, and rotary equipment wears out. Tuning instruments and devices regularly contribute to greater process yield. Transmitters can be calibrated, and control valves can be inspected for damage and tuned for optimized proportional-integral-derivative (PID) values; other equipment should be tested and maintained as needed. These activities should be part of routine maintenance at any facility, so conducting smart, efficient maintenance can prolong uptime.
Optimize human interaction
Even the most sophisticated unmanned facilities require some level of human interaction for sustained operation. An operator who knows the entire process and all its intricacies is equipped to respond to anomalies and prevent serious damage if a situation arises. In addition to operator training, efficient alarm optimization and aesthetic HMI designs can improve operator concentration and reduce overloading.
One of the most significant routine costs at any plant or facility is maintenance. Standard maintenance procedures require routine inspections, measurements, and recording data. While this method of maintenance is widely practiced, it often wastes time of the personnel checking perfectly functional equipment and unnecessarily extends planned maintenance time. The advent of highly accurate and precise digital sensors and the concept of digital oilfields have opened up a window of possibilities for optimizing maintenance processes and reducing overheads.
Condition-based monitoring and maintenance (CBMM) is a relatively new domain with great potential for predictive maintenance. With large-scale data storage capabilities available to even the remotest stations, all it takes are a few analyses of equipment and instruments to determine which are close to failing and which do not require any maintenance—in effect reducing maintenance time and cost significantly. The failure trends of all devices also help design a predictive spares inventory, reducing warehousing costs and the time needed to get replacements for failed components.
Combining these capabilities with the Industrial Internet of Things (IIoT) and cloud storage allows greater access to this information, whether in a central facility or on mobile devices. This holistic view of all midstream assets and facilities, complete with health status and maintenance reports, can help managers be more responsive to operations while senior management can focus on productivity.
Most optimization activities will be a mixture of the different areas of optimization discussed above. What makes midstream process optimization work is a well-experienced team of experts who can take care of minor details and provide adequate support and training where needed. It may seem like a daunting task for end users who don’t have very experienced optimization teams or the means to carry out these tasks themselves, but there are many system integrators and original equipment manufacturers (OEMs) who provide these services throughout the world.
Ahmed Habib, assistant manager marketing operations, Intech Process Automation; Jahangir Malik, process optimization engineer at Intech Process Automation. Intech Process Automation is a CFE Media content partner. Edited by Chris Vavra, production editor, Control Engineering, CFE Media, firstname.lastname@example.org.
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