Nature of Design

Any production plants require design of manufacturing process that is performed by chemical design engineers. Chemical engineers develop and evaluates the possible designs to meet the targets of the production plant. The design of the project is affected by external and internal constrains as described in Figure 1.1. Engineers should identify the best design option to achieve the design specification considering the impact of constraints. External constraints are generally fixed and include physical law, government regulations and standards. However, internal constraints are variable depending on the feasibility to perform. Economic considerations are obviously a major constraint on any engineering design: plants must make a profit. The commercial operating company which produces chemicals mainly focuses on maximizing benefits. Besides, sub-objective like to minimize operating costs, to reduce investment, maximize yield, reduce labor requirements, reduce maintenance, operate safely will be considered.

 

                                                                   

The stages in the development of a design, from the initial identification of the objective to the final design, are shown diagrammatically in Figure 1.2   

                                             

                                                                      Figure 1.2  The design process

Chemical engineering projects can be divided into four types, depending on the novelty involved:

• Development of new plants: implemented by EPCM company (Greenfield projects)
• Amendment and extension of existing plants; generally implemented by the plant design group (Brownfield projects)
• Production scale-up or debottlenecking projects to match the sales demand 
• Development of new processes from laboratory research or through pilot plants, to a commercial process.