Elaboration of the process flow diagrams . From the idea to the industrial plant

As Napoleon Bonaparte once said, "a good sketch is worth more than a long speech". So, to effectively describe a production or transformation process, it's essential to use diagrams with appropriate symbols that are understood by the various parties involved in a project. In industry, "process" refers to the tools and methods used to produce a product by following a number of elementary operations. By tools, we mean devices or equipment used to carry out some of these operations. Methods are both the order in which these operations are to be performed, and the operating conditions to be used. The process flow diagram summarizes this information in a single document, using a symbolic graphic language that must be common and universal if it is to be understood by all.

The language of the diagrams must be common to the various scientific professions that contribute to the design and development of the process: chemistry, biochemistry, physical chemistry, chemical engineering, instrumentation, mechanics... but also to all the company's players, whatever their activities or their level of execution and decision-making.

Diagram language must be universal. Graphic symbols, even if there is no single international standard, must be clear enough and close enough to each other to be used and understood by all professions, research, engineering, production, equipment manufacturing... whatever the original spoken language.

Schematics are at the heart of design, dimensioning and manufacturing methods. They are an integral part of the industrialization process, from the laboratory to the factory, from design to operation, and must be the tools used by all those involved. The quality of this mode of representation is one of the key factors in the success of exchanges between players, whatever the stage of development, industrialization or operation.

This article sheds light on the use of different diagrams throughout the life of a project, from the idea to the industrial unit, via the various development phases. It proposes an elaboration method and addresses optimization issues. Finally, it attempts to introduce everyone to the language of process diagrams.

After a brief presentation of the industrialization process for a product and the process for obtaining it, in order to place ourselves in the industrial context, the contribution of the various schemes is described. Finally, the following two sets of diagrams are analyzed in greater detail:

• block diagram. It describes the chemical and physical stages of the process, and the flow of materials and heat from raw materials to the finished product;

• the process flow diagram...