Lesson 9. Experimentation in Pilot Plant

The pilot plant is a physical model and should be a “copy” of the corresponding industrial unit, with equipment scaled down in size to approximately 1/100 – 1/10 of the modelled unit.

Pilot plant experiments serve to obtain more information and data in the following areas:

1. Market survey: A determined new product amount can be produced in the pilot plant, to test its acceptance and to decide whether it would be economically profitable.

2. Design data: The behaviour of a given operation or unit process can be found under conditions impossible to duplicate in the laboratory.

3. Products and raw materials: A pilot plant is usually needed to characterize food products and to evaluate the development of certain raw materials into specific products.

4. Optimization data of a running plant.

9.1 Size and structure of the pilot plant

The most important criterion in determining the size and form of a pilot plant is the principle of similarity, a principle first formulated by Newton.

If, fluids are handled in the pilot plant, three types of similarities involved in fluid dynamics must be included:

1. Geometric similarity: Both the pilot plant and food processing plant should have the same physical form or at least the same geometric dimension relationships.

2. Kinematic similarity: The same velocity relationships should exist in both the pilot and food processing plants.

3. Dynamic similarity: In both the pilot and food processing plants, the same force relationships should exist. For example, the turbulence regime should be similar on both scales when fluids are handled.

If the process simulated in a pilot plant involves chemical the following similarities apply:

1. Thermal similarity.

2. Chemical and biochemical similarity.

9.1.1 Minimum and Maximum Size

Several factors can affect the size of a pilot plant. In general, the minimum size is set by the minimum product amount required for quality analytical control.

The maximum size of the pilot plant is set by the amount of processed product needed in order to test market acceptance.

9.2 Types and application

When product production in amounts large enough to conduct market acceptance tests is required, the pilot plant is called a semi-commercial plant.

The most common applications of a pilot plant are as follows:

1. Product studies

• Quality characterization

• Influence of process conditions on product quality

• Development of new products

• Studies of market acceptance

• Raw material characterization

• Evaluation of aptitude for industrialization of different raw materials

• Setting the most suitable process conditions from an economic point of view (cost minimization) and a product quality point of view (to obtain a product of given quality). Process technology is optimized.

• Study of process equipment alternatives to carry out given food processing steps or unit operations.

• Development of new process technology.

• Development of new process engineering or process equipment.

• Reliable evaluation of mass and energy balances and food physical properties

• Study of energy recovery possibilities in process systems

1. Raw material studies

1. Process technology and engineering studies

1. Auxiliary system requirement studies

Improvement and evaluation of alternatives for control systems