Today, the basic aspects of designing chemical manufacturer is done by chemical engineers. Historically, this is not always the case. Before the establishment of chemical engineering, many chemical manufacturers were established in a disorderly way. In 1887, George e Davies opened the first chemical engineering course in Manchester University. The course covers all aspects of industrial chemistry practice in the form of 12 lectures. Therefore, George E. Davis is considered to be the first chemical engineer in the world. Today's chemical engineering is a profession, and those experienced professional chemical engineers can obtain the "chartered" engineer qualification through the Institute of chemical engineers.

In factory design, less than 1% of new design ideas can be commercialized. In this solution process, cost studies are often used as a preliminary screening to eliminate unprofitable designs. If a process seems profitable, other factors should also be considered, such as safety, environmental constraints, controllability, etc. In factory design, the general goal is to construct or synthesize "optimal design" near the expected constraints

Most of the time, chemists study chemical reactions or other chemical principles in the laboratory, usually small-scale "batch" experiments. Chemical engineers use the chemical information obtained, together with their own expertise, to transform it into a chemical process and to expand the batch size or capacity. Usually, before a large plant is built, a small chemical plant called a pilot plant is built to provide design and operational information. Based on the data and operating experience obtained from the pilot plant, an expanded plant can be designed to produce at higher or full capacity. After the basic aspects of the plant design have been determined, the mechanical or electrical engineers may be involved in the mechanical or electrical details, respectively. Structural engineers may be involved in the design of the plant to ensure that the structure can withstand the weight of the unit, piping and other equipment.

Unit, flow and fluid systems of chemical manufacturer or processes can be represented by block flow diagrams, which are very simple diagrams or more detailed process flow diagrams. Water and other pipes are represented by lines, and arrows indicate the usual direction of material flow. In block diagrams, units are usually simply represented as blocks. More detailed symbols can be used in the process flow diagram to show pumps, compressors and main valves. The range of possible values or material flow rates for various material flows is determined using material balance calculations based on the required plant capacity. The energy balance also calculates the amount of heating and cooling required in different places based on the reaction heat, heat capacity, expected temperature and pressure at different points, and determines the size of the heat exchanger. The design of a chemical plant can be shown in more detail in the piping and instrumentation diagram (P & ID), which shows all piping, piping, valves and instrumentation, usually with special symbols. Displaying a complete device in a P & ID is often complex, so only a single unit or specific fluid system is usually displayed in a P & ID.

In factory design, the size of each cell is for the maximum capacity that each cell may have to process. Similarly, piping, pumps, compressors and associated equipment are sized according to the flow they must handle. The design of the power plant should also include utility systems such as power and water supply. Additional piping for unconventional or standby operating procedures, such as plant or unit startup and shutdown, may have to be included. Fluid system design usually includes individual units or parts of the plant around the isolation valve so that a part of the plant can be isolated in the case of a unit leak. If pneumatic or hydraulic valves are used, a pressurized line system connecting the actuator is required. Any point requiring sampling should include sampling lines, valves and access to them in the detailed design. If necessary, provisions shall be made to reduce the high pressure or temperature of the sample flow, including pressure relief valves or sample coolers.