Advanced Process Control (APC) Benefits In Chemical Industry

The chemicals market is very competitive, volatile, and fast-paced. To maintain a strong market position, companies need to look harder and deeper into their equipment, production, and operations to ensure the production chain is optimized. At leading chemical companies Advanced Process Control (APC) is the main process control formula for reaching a higher level of process operational excellence.

Advanced Process Control (APC) is a process control and optimization technology that takes into account the multivariable interactive nature of process units to reduce variability and drive the process to an optimum. So, the goal of well-designed APC strategy in the chemical industry is very simple: to maximize margins while meeting customer expectations by moving the process to a more optimal point. This results in consistently operating the unit close to the maximum possible profit day in and day out, safely and reliably. The following criteria can quantify the benefits associated with an APC process:

• Production increase: Typically, Advanced Process Control (APC) projects have proven to increase capacity by 3% to 5%. By reducing the variability in the process and operating closer to limits, APC debottlenecks the process, or part of it, allowing higher production rates.
• Energy savings: Energy savings from APC implementation have been reported to be in the range of 3% to 15% depending on the process and current operations. Most of the time, utility management is a complex control issue that spans across the site and at times also affects the electric grid. These system applications can be designed to achieve benefits by reducing utility costs up to 60% the system also can be used to optimize energy production, such as boiler loads, gas turbines, or other.
• Quality improvements: It’s important to reduce variability in the final product quality. Some products are sold at a value that depends on the quality variability of the batch produced. Many companies report a reduction in standard deviation of product qualities of up to 50% using Advanced Process Control (APC).
• Yield improvement: Many organizations experience a yield improvement of 2% through APC deployments, typically achieved by optimizing the reactor temperature and/or the ratio of feed to the catalyst or the separation portion. In separation processes, such as distillation columns, maintaining the specifications by APC on the final product can increase the yield of the desired product by increasing impurities up to the contracted specifications.
• Grade transition time optimization: During different processes, the production wheel cannot be optimized to market needs, as difficult and time-consuming transitions may be rejected by operations resulting in low-value products produced during these transitions. Through the APC system, it is possible to “bust the production wheel” and produce grades when they are in demand while minimizing the time when the low-value transition products are produced. It’s common to achieve 20% to 50% reduction in grade transition time using the appropriate strategy.
• Recycle ratios optimization: Units that can be recycled qualify to collaborate with the APC system. The good strategy allows for optimizing the feed-to-recycle ratio to maximize throughput and/or maintain quality at specifications and/or to satisfy equipment constraints.
• Emissions control improvement: The implementation of APC can help control environmental constraints. By using this process, the emission equipment (such as furnaces and boilers) is possible to operate closer to the emissions limits without violating them. Using APC strategy also helps to decrease energy usage and minimize costs to meet NOX, SOX and COX emissions constraints.
• Exploiting ambient temperature effects: APC system has proven to exploit the benefits associated with ambient conditions. Ambient temperature has an effect on compressor performance, condensation capacity, gas turbine operation, cooling water temperature, refrigeration capability, gas volumes, and many more process-related conditions. Therefore, units that are affected by ambient conditions can benefit from APC applications as they can anticipate these changes and adjust process parameters accordingly.
• Disturbance effect reduction: Without Advanced Process Control (APC), disturbances arising from upstream or downstream will affect process units and reduce margins. With APC technology, units will constantly react to the disturbance optimally.

— Authors: Tushar Singh & Kate Kulik, Aspen Technology Inc.