Process heaters contain a process fluid in the tubes, rather than water. The process fluid is usually a hydrocarbon. These heaters come in tow main varieties: vertical cylindrical and cabin style. Vertical cylindrical heaters comprise a cylindrical flame zone surrounded by process tubes. Cabin style heaters are rectangular with wall and roof tubes. The radiant section comprised of overhead tubes that cannot directly view the flame. Convective tubes receive their heat from the direct contact of the combustion gases. The transition from the radiant to convective sections is known as bridgewall.

Process intensification is a concept that is introduced in the chemical industry for the purpose of reducing environmental emissions, energy consumption and materials consumption. The principle of process intensification can be used in related industries as well; textile finishing is an exemplary activity where it may have a significant long-term added value.

Process optimization is the technique of making changes or adjustments to a process, to get results. It is a method to determine the most cost effective solution to a problem or design for a process. This technique is one of the major quantitative tools in industrial decision making.