In the present research, a Pressurized Liquid Extraction (PLE) unit has been preliminarily designed to extract bioactive compounds from medicinal plants. The design steps included: 1) Developing design bases with general information about the process; 2) Preparing a concept process flow sheet in which the unit operation type, the required equipment, the main input and output flows and the flows related to the utilities are shown; 3) Determining the operational mode of the process; 4) Determining the type of equipment; and 5) Doing calculations and balancing energy and process materials. In this design, 500 kg of dried chopped plant and a combination of ethanol and water as solvent were used as input materials to the extractor. A batch mode is considered for the extraction operation and a continuous mode is considered for concentration operation. Unit operations were designed based on a fixed-bed extractor, and subsidiary equipment required were determined according to the desired conditions for the process also, falling film evaporator is used to concentrate the extract. By determining the flows, balancing the materials and energy, and doing the process-related calculations, the Process Flow Diagram (PFD) was finally obtained.
