Processing costs ={ Equipment costs / Payback time } +{ Cost of utilities }+{ Additional environmental costs } The economic potential at any stage n is then EPn=EPI/0{Processingcosts} For this process PFD EP can be determined as: EP=EPI/0{Rxtorcosts/paybacktime}{costofsepns}{utilitiescosts}{additionalenvironcosts} You can assume that environmental costs are 5-6\% of product and by-product sales. It can be assumed also that sales/(all other costs in EPI/O ) ratio is 1.73.0. Use this information to determine annual EPI/O after obtaining the sales costs of products and by-products [assume 340 days of manufacture per year]. Provide a reference of where you obtain up to current sales cost data. (g) As you can realize, there are a lot of opportunities for energy integration (even steam generation) for this process. Identify points in the proposed PFD where additional heat exchangers are located. Compare the PFD to one involving a catalytic process (locate in patents) in terms of energy integration. Problem 4 (Development of PFD and Economic Performance) The hydrodealkylation of side-chain aromatics to non-substituted parents is a major process in petrochemical processes [for example, benzene is the starting raw material for producing a top commodity chemical like isopropyl benzene (also called cumene) which accounts for about 8% of the total worldwide propylene consumption. Cumene is mostly used to produce phenol and acetone]. The conversion of toluene to benzene is carried out via the reaction: C6H5CH3+H2C6H6+CH4 at 30-50 bar, either thermally at 550700C or over a suitable catalyst. Thermally, the conversion is 6080% with selectivity 95% [of course, selectivity is higher with catalyst]. Other significant side reaction produces diphenyl via reaction: 2C6H6C12H10+H2 (i) Feeds are introduced by mixing pure toluene and hydrogen with 5% methane. Hydrogen is recycled back to the process but to avoid accumulation of methane in process some purge stream of H2 /methane is added to the process from which valuable methane is recovered via membranes. (ii) All toluene is recycled. But ratio H2 /toluene of 5 is maintained at reactor inlet to avoid C formation. We will assume reaction takes place at 40 bar and temperature of 600C. (iii) Raw feeds will be heated (in furnace) before introduction to the plug flow reactor and the reactor outlet products will be cooled before sending them to a single stage flash unit. A simulation of the flash unit at 40 bar \& 305K using Peng-Robinson EOS gives the K values in the table (table includes operating data too). win/out or ilowsneet; -rkmoi (a) Obtain boiling points of toluene, diphenyl and benzene and identify the scheme used to separate them into their pure form. (b) Investigate any patented catalytic process that will improve selectivity. Show also its PFD. (c) Determine ratio of gas recycle rate to the molar flow rate of input. (d) Develop a PFD for the process based on the data provided. (e) Identify useful products for this process. (f) Economic potential EP is generally evaluated in stages. The first stage EPI/O is EPI/O={ product value }+{ By-products value }{ Raw material costs } { Auxiliary material costs }{ Ecological costs }