Benzene, toluene and xylene are important precursors in the manufacture of petrochemicals. The feedstock can be reformed naphtha. You have been contracted to design the distillation column for the recovery of benzene. You may assume that a constant flow of 150 metric tonnes per hour of feedstock is to be processed. Typically, a column will have a feed stream pumped at a certain temperature and pressure, a vapour stream that is cooled by an overhead condenser, a reflux stream that is pumped back to the column by a reflux pump, and a reboiler that adds heat to the process. Data: Feed Composition: Benzene 0.77 Toluene 0.22 p-xylene 0.02 o-xylene 0.01 m-xylene 0.021 Temperature and Pressure You choose, but ensure that these parameters are suitable to comply with the clients specification. Note that some of the materials may need to be in a liquid state and that the pressure needs to be at a level that will cause the benzene to flash when it enters the column. Required Purity of Benzene 99 % Data for Pump and Line Sizing The base of the feed tank is vertically elevated 3 metres above ground. The pipe descends from the base of the feed tank and, moving left to right, travels a distance of 2 metres laterally before entering the feed pump. The pipe exits the feed pump and travels 4.5 metres laterally before entering the heat exchanger. The pipe then exits the heat exchanger and travels 2 metres laterally to a point below the distillation column, the pipe then vertically ascends 9 metres to a bend, and continues 2 metres laterally from the bend before entering the side of the distillation column. The pipe carrying the distillate exits the side of the distillation column and descends to the discharge pump which is located near the base of the distillation column. The pipe then exits the discharge pump and travels 30 metres laterally to a point below a tank, it then vertically ascends 20 metres to a bend, and continues 2 metres laterally from the bend before entering the side of the tank. Another pipe exits the base of the distillation column and enters the bottoms pump. The pipe then exits the bottoms pump and travels 90 metres laterally to a point below a vessel, it then vertically ascends 8 metres to a bend, and continues 1.5 metres laterally from the bend before entering the side of the vessel. All pumps are at ground level. You may assume that all piping will be Schedule 40 Mild Steel.

Using the UniSim software program, develop a PFD to successfully comply with the clients specification of designing a distillation column for the recovery of benzene. Once you have completed this simulation furnish the following requirements: a) Provide a PFD of this chemical engineering process showing the main equipment in this process. Ensure that the PFD includes a shortcut distillation column, main distillation column, feed pump, heat exchangers, reboiler, bottoms pump, and distillate pump.

b) Develop a stream table as a part of the PFD for all the major streams. Remember to go into the Column environment for the overheads and reboiler information

c) Size the piping and pumps. Ensure that you include the: 1. Feed pump. 2. Distillate discharge pump. 3. Bottoms pump

d) Draw a P&ID from the feed pump to the discharge streams. This drawing requires you to accurately size the lines and the pumps. Note: You may use an appropriate software program (such as Microsoft Words AutoShapes, Microsofts Paint, or another suitable program such as Visio) to draw the required P&ID.

e) Briefly discuss the research methodology and challenges which you adopted for sizing the piping and pumps in your UniSim Model. Ensure that your answer includes a justification for selecting the specific piping and pump sizing in your UniSim model.

f) Briefly discuss about the importance of simulation tool in engineering and how it will help engineers to improve efficiency.

g) Underline the importance of sustainable practices and environmental considerations in chemical processes by providing a detailed discussion of the implications of these in the system which you have designed.