Process plants, either existing or new ones, have many objectives to achieve. Most of these objectives are common such as best safety, health and environmental compliances; reaching its production and quality targets; minimizing its products loss; minimizing its raw materials loss, using lower number of units less maintenance requirements, less energy consumption and so on.
Plant Energy Efficiency Assessment Methodology
Since late seventies of the last century some new objectives have emerged and most of industrial facilities are now giving them an increased attention, such as minimize fuel consumption; minimize energy intensity; maximizing power export, if applicable, and so on. Recent guidelines for process plants design and operation are currently advocating and pushing for newly coined terms such as; design-to-capacity, control-to-specifications, reliability-by-application, multi-generation, total-site-integration, simultaneous design and operation, healthy-aging-design with retrofit-in-mind and many more.
The term “Energy Assessment” refers to the methodology of collecting and analyzing available energy utilities related process data without losing the context of the whole process requirements mentioned above in order to establish the “big picture” of the energy requirements of a particular facility. Then, it identifies component-based-energy efficiency optimization opportunities from the operating cost point of view and capital cost of energy and process sub-systems point of view too for implementation. Striking the right balance between capital and operating costs will define the close-to-optimum solution of the energy problem in the retrofit of existing facilities or in the design of any new one.
Energy assessment studies for existing plants are very common applications since the seventies of the last century, while such practice for new plants is not much. In grassroots projects available data to conduct energy assessment studies are a little uncertain, time is critical and there are infinite combinations of options. Therefore, the energy assessment of new plant/project has to be conceptual, fast and rigorous with the right level of details.
The purpose of this chapter is to start the manual with an overview and simple “scope of work” definition for the conduction of new plants or expansion projects energy efficiency optimization study. Normally, the optimum time to conduct such energy assessment study is the earliest date after the preliminary process flow diagrams (PFD) is seeing the light; including mass and heat balances and the identification of the plant fuel and power consumption estimates. In big projects, it is recommended to avoid any conflict of interest among the project parties is to conduct such studies by independent consultants and not by the process licensor or the project engineering contractor.