(65f) Pilot Plant Screening Steps, Test Plan Development, Execution, and Results Analysis As Related to Thin-Film Evaporation

Chemical processors invest billions of dollars each year in capital equipment. Many of the processes are new and novel while some are established yet have long running issues that have not been solved. The potential costs of downtime from troubleshooting in the field during production is not justifiable so many companies continue to run their processes at sub-optimal process conditions. Before finalizing a purchase order, engineering, operations, and business leaders want to know that they are signing off on a proven solution.

The solution to vetting new processes or investigating existing ones is utilizing a pilot plant. Information is gathered on pilot scale equipment to scale-up to production scale equipment. The equipment sizing from pilot plant data is used to get ballpark pricing, which can be used to establish a business case for the product you are investigating. Another benefit of pilot plant testing is the small relative quantity of feed material required. It may be difficult to procure mass quantities of feed for new applications, typically using lengthy batch preparation. For existing production evaluation, you can divert a small stream of process material to run the trial without major production losses.

At LCI, we perform testing and piloting services for customers to evaluate new processes and troubleshooting existing processes utilizing our thin-film evaporation and drying technologies. LCI generates processed material samples for its customers for evaluation to determine if the end product will be well received by their customers and profitable enough to invest capital dollars. Pilot testing is an attempt to validate a process through quantitative means via logging of process variables such as mass flow rates for feed, concentrate and distillate streams, heating media type and conditions, operating pressure, and process temperatures and referencing run data versus analytical data from sample analysis. This data is used to draw a correlation between the process conditions and product specifications for quality, whether that be residual solvent content, color, viscosity, reaction completion, et al.

Before pilot testing, new processes are screened using a relatively small sample (~1L) at lab-scale. This qualitative testing determines if there are any product characteristics (such as fouling, foaming, temperature sensitivity, etc) that may present major issues during pilot scale operations. In addition, test conditions parameter ranges can be determined during the sample evaluation. A database of past tests is also utilized to determine any instances of similarity to past tests. These past tests can be used to determine process condition targets or foretell pitfalls that can be avoided with a certain test setup.

Once sample evaluation and database research are completed, a test plan is created with a planned layout. Careful consideration of evaporator style (size, rotor type, heating media, bearing design), material handling needs (pumps, piping, heat tracing, valves, heating media, feed vessel setup), and scope of test objectives determine test time, setup, and quantity of material required.

Execution of pilot plant testing requires a good plan and a skilled operator crew. One of the main goals of pilot testing is to find the boundaries of what the equipment can do and push it to failure to determine the maximum operating conditions related to product temperature, viscosity, concentration, or some other limiting variable.

Once a test is completed, the results logged during the test are compared to analytical tests performed on the collected samples. Optimally, statistical analysis will clarify a relationship between process conditions (feed rate, heating temperature, etc) and product quality specifications (concentration, color, etc). These relationships uncover the optimal test conditions and production-scale operational conditions.

The optimal test conditions/run are the basis for sizing of larger, production scale equipment. For evaporators, the main goal of testing, besides verifying that the equipment type can handle the qualitative restraints of the process, is to determine a U value and subsequently an outside film coefficient. The scale-up requires revised values for the outside film coefficient and conductivity portion of the U value calculation, which will change as the equipment grows in size and the wall thickness changes as per the relevant pressure vessel code.

Pilot plant testing is an essential part of chemical process R&D and production troubleshooting. LCI offers a complete pilot plant test to service the chemical processing industry such as food, pharma, specialty chemical, polymer/plastics, solvent recovery and waste minimization, and others. Alternatively, production facilities with this technology can install a pilot-scale, evaporator setup in their R&D pilot plant to evaluate new product types, batch recipes, or process conditions.

In conclusion, this oral presentation will present an overview of the pilot plant screening steps, test plan development, execution, and results analysis as related to thin-film evaporation. I have a few case studies to illustrate pilot plant importance and lessons learned along the way.