The Chemical Process Consultant’s Role
Whether improving an existing plant or building a new biorefinery, the chemical process consultant should be your first stop. In existing plants, yield improvements, energy efficiency and solvent recovery are the most common projects. When properly scoped and executed, these projects tend to have immediate impact on efficiency and economics. The consultant identifies the opportunity and scopes, and often manages the project. A couple of typical projects are outlined below.
Methanol Recovery: A biodiesel facility was losing 150 pounds of methanol an hour to the vent operated at a slight vacuum, and the originally designed cooling water condenser was only partially effective. Enhanced Biofuels used a combination of process simulation and analytical data to confirm the magnitude of the losses and recommended a chilled water condenser. Given space limitations, a low-footprint condenser with small pressure drop was recommended and installed. Methanol losses were minimized and the project had a payout of a few months.
Heat Recovery, Additional Capacity: A plant needed additional capacity and one of the distillation columns was identified as the bottleneck. One of our engineers tackled the problem by performing an energy balance and hydraulic review to uncover that the bottleneck was two-fold. The product pump was undersized and the heat requirement could not be met by the existing heater. Heater replacement was prohibitively expensive. Process simulation was used to show that product heat recovery could be used to cost-effectively add the required heat to increase capacity. A feed bottoms heat exchanger was recommended and installed with new bottom pumps. At the completion of the project, the distillation operated at higher capacity and lower energy consumption per pound of product.
Technology improvements are a special type of project where the plant is expected to perform better than it was originally designed for. Examples include using a different feedstock, changes in product specification, changes in equipment design, and large increases in capacity. An important role of the chemical process consultant in this type of project is technology review and selection.
Dryer Specification, Throughput: In a newly built plant, a fluidized bed dryer was not meeting design throughput or moisture specifications. We used a bench-scale dryer and worked closely with the plant to collect operating data. As a result, addition and modification of the dryer internal baffles was recommended to increase dryer throughput and achieve moisture specification. The dryer now operates at 20 percent higher throughput.
When facing the challenge of a new biorefinery, one should consider bringing on board a chemical process consultant to act as an “owner’s representative,” a technology- and business-savvy project manager who will help manage the project development process.
Feasibility Study, Alternative Review: This provides preliminary capital cost and pro forma, and vets the business model, identifies major risks and reviews alternative technologies, sites, feedstock choices, utility types. The owner’s representative may undertake or oversee the feasibility study.
Front-End Engineering, Design: FEED defines and freezes the project scope, and process equipment. Long lead items will be specified as ready to purchase. The cost estimate might be refined to plus or minus 10 percent. The owner’s representative will help to choose and supervise the engineering company.
Detailed Engineering: This refines the project documents to “ready for construction” with detailed design of equipment, foundations, structures, electrical and piping routing, instruments, etc. The owner’s representative will facilitate communications and manage scope, cost and schedule.
Procurement: Typically led by the engineering company and the general contractor. Long delivery and special technology items may be procured by the owner’s representative.
Construction: Led by the engineering company and the general contractor. The owner’s representative is least involved in the construction of the project.
Startup, Performance: This phase starts by ensuring that operating and maintenance manuals are ready and operators are properly trained. Once mechanically complete, the unit will go through a shakedown period until it reaches nameplate capacity and product specification. At this point, a third party will usually be brought in to certify performance. The owner’s representative is intimately involved in this stage of the project.
Optimization: This is adjustments as a result of changes in market conditions, utility prices, product specifications, and feedstock changes. The owner’s representative may stay involved with optimization efforts given the expertise developed during the project.
Author: Roman Wolff
President, Enhanced Biofuels