Correct Process Configuration: Pivotal to Energy Optimization and Conservation
Jinal Sevak
Sr Executive Engineer
Systems Engineering
Linde Engineering India

Attaining energy efficiency is a big concern for process plant owners as they capture a large share in the operational expenditure pie. Here in this article, the author, narrates how energy efficiency can be achieved through implementation of proper measures starting from the design stage itself.

Energy management is one area where the industry has seen a constant growth. In today's world with growing challenges in terms of high energy cost, depleting resources, and ever-increasing energy footprints, it is vital for any industry not only to monitor, but also to evaluate the optimum energy balance within the complex. A large share of the OPEX is usually the energy costs With ever increasing tightening of margins and knowing that there is nothing much to play around with the feedstock price, the real game changer can be the energy cost.

Role of a Technology Licensor
A common misconception about energy management and optimization is: it its optimization at a later stage during the energy audit or energy study in plant life cycle. This is where a technology licensor plays a key role.

Energy conservation issue(s) can be addressed at various phases of plant life cycle in order to have a positive impact in bigger magnitude. However, to sum up broadly, those issues can surface & be worked upon either during the project phase for a new chemical process plant or during the operational phase of an existing process plan.

When a new process plant is designed, the role of the process plant owner has equal importance to that of technology licensors. It is of note that the process design basis defines the overall feed, fuel, and utility requirements. Any process technology can have various configurations which are adopted and tailor-made to suit the customer needs, local site conditions, and the overall chemical complex. The price, availability, and reliability aspects of utilities viz steam, cooling water, and power - along with feed and fuel prices - are critical in deciding the correct process configuration.

For an instance, a standard steam of methane reforming a hydrogen plant can have its configuration either with excess steam production due to export steam credit, or without excess steam production owing to no/minimum export steam credit.

In one of the process configurations, condensate lifting devices are installed in order to pump a high amount of continuous condensate (from reboilers) with insufficient condensate system pressure, which - by using high pressure motive steam - can push the condensate at required destination vessels. This upshots the pumps to avoid their usage and therefore consequently leads to huge electric consumption on a continuous basis. This is another instance of process configuration overarching the whole chemical complex utility balance and the utility prices.

In one of the recent projects at Linde, for an acid gas processing plant using Linde's process technology, a process configuration was adopted to reduce the overall plant footprint, energy footprint, and thus leading to the unit's CAPEX and OPEX reduction. An acid gas removal unit can be broadly subdivided into an absorption section and a solvent regeneration section. The unit had two separate absorption sections with different feed compositions. Generally, it calls for two separate regeneration sections considering various plant operational cases given by the customer. However, a common regeneration section was selected without compromising on the clients' requirements in terms of various phase wise startup - operational as well as maintenance-based, and also in terms of other operational requirements. Such innovative and sustainable solutions can help customers to reduce the energy cost drastically during its design stage.

Key aspects during the project stage can be, but not limit ed to:
  • Detailed analysis of the client requirements
  • Site conditions, utility balance, and an inclination towards energy conservation
  • Innovative yet sustainable solutions that will keep pace with tomorrow's challenges
  • Review of the plot plan with respect to process design
  • Selection of equipment and components for energy loss reduction
  • Adaption to process controls for process performance optimization and fine tuning
  • Experience and implementation of lessons derived from past experience
Moving on to the operational phase of a process plant, it is vital that the process plant owner does carry out regular energy audits and tracks the plant's performance. There can be various recommendations and/or action items emerging out of such energy audits and which can fall under short-term, medium-term, or long-term measures basis the estimated payback period.

A technology licensor can also aid their customers at this stage wherever and whenever deemed fit. At Linde, we understand that most plant operators are keen to increase as well as to maintain the plant's uptime and performance. Having said that, at the same time, plant managers are under growing cost pressure and therefore need to exploit the efficiency enhancement measures. Such challenges can be met onsite as well as through remote audits either by revamping the components or modernizing control equipment, or by carrying out feasibility study in order to weigh the best foot forward aiming to match the customers' expectations.

Conclusion
Thus to close the discussion, it is of note, any amount of effort put towards process configuration optimization at the design stage of a plant has a better pay off than that of the operational stage. For a technology licensor as well as for a plant owner, it is therefore vital to review thoroughly, to share expectations, and to think about innovative, sustainable, and energy efficient processes.