OTTO-VON-GUERICKE-UNIVERSITÄTMAGDEBURGFaculty of Process & Systems Engineering Simulation Lab WS2017/2018Supportedby:[email protected] “Productionand Distillation of Cumene of the Hock Phenol Synthesis” Date: 26.01.2018Group Member: Course of Study Matriculation number:Mihir Khandelwal PSEE 218017Sannidh Ramoliya PSEE 220845Table of Contents 1. Introduction2. Methods:Properties and Procedure3.
Results4. Conclusion5. ReferencesAppendix A: ASPENPLUS Simulation ModelAppendix B:Results1. Introduction Cumene is produced with the reaction between benzeneand propylene, the process under consideration is hock-phenol process. In this,the cumene produced is utilized to obtain phenol and acetone. The process wasdescribed by Hock and Lang in 1944. The reaction to form cumene is desirable,but reaction between cumene and propylene which forms diisopropyl-benzene(DIPB) is undesirable. Both the reactions are irreversible.
The primary use of cumene is as a feedstock for themanufacturing of phenol and acetone; however, it is used as starting reactantsfor various chemicals. It is used as thinner in paints, enamels, lacquers.Also, it is used in the production of rubber, paper, iron and steel. § Cumeneproduction reactions: The reaction ofbenzene with propylene is as follows: C3H6 + C6H6 ® C6H5-C3H7 C3H6 + C6H5-C3H7 ® C3H7-C6H4-C3H7 Cumene (Isopropyl benzene) is an important componentin global chemical industries. As per a report (Wildcat market researchsolution), in 2011 the production of cumene was 12 MT (million tons), which isexpected to increase by 50%, to 18 MT by 2020. This makes it a 20 billiondollars industry per year. The demand is increasing in Asia-Pacific region,which makes cumene production process important.
The process can be simulatedusing ASPEN, and the results can be obtained considering selectivity,conversion, and feed in the mixture. With this, ASPEN model, we can vary feedand check how much cumene is produced. Furthermore, description of process flowmade using ASPEN is discussed.
2. Methods:Properties and Procedure § Propertiesof cumene: Description: Itis a colorless liquid with gasoline like gasoline like odor. It is soluble inalcohol, benzene and various inorganic components, but it is insoluble inwater. It is highly flammable.
BoilingPoint: 152.4 °CDensity: 0.8618 g/cm3 at 20 °CMeltingPoint: -96.0 °CRefractiveIndex: 1.4915 at 20 °CFlashPoint: 39 °C, whenthe cup is closedSolubility: Not soluble in water,miscible in benzene, acetone and ethanol.Reactivity: Combustible, incompatiblewith nitric acid, oxidizers and sulphuric acid.
(Reference:Australian Government, Department of the Environment and Energy,http://www.npi.gov.au/resource/cumene-1-methylethylbenzene) § ProcessEconomics:Thecosts of raw materials and products when considered for long term period, ismuch higher than the cost of construction costs, energy or any initialinvestments B. Process economics states that the reactants (Feed) conversionto product should be as high as possible.
Two principles are stated as per C.(1)The feed mixture contains benzene and propylene under normal atmosphericconditions. The propylene feed stream contains impurity of propane, whichshould be taken out. Propane under the reactor is inert, so its separation isvery time consuming and difficult. Instead, the better trade-off would be highconversion of propylene.(2)The undesirable by-product, which has only the value of fuel, should be kept aslow as possible, as it consumes reactants.
§ ProcessDescription: Thereactants benzene and propylene stored in their respective tanks are fed in thereactor in liquid form, the feed temperature is kept under atmosphericconditions, temperature is 25°C and pressure is 1 atmospheric bar. The feed iskept in the ratio of 2:1, benzene to propylene respectively. This can be variedas per needs to obtain different results.
The temperature in the reactor ismaintained at 360°C and pressure of 25 atmospheric bar C. Cumene obtained from benzene and propylene, alsoproduces undesirable by-product, which is of no relevance to us. This can bedone either by increasing benzene so that cumene and propylene concentrationsremain low but this will increase cost of separation A. Other method would beif we increase the size of reactor provided the cost of material isinexpensive.
If, the material cost is high, small reactor is theonly feasible option. Thedesign of cumene production and distillation process is simulated using AspenPlus software. The process flow diagram (PFD) of the entire process isillustrated below.Figure 1: Process Flow Diagram of Cumeneprocess Twodistillation columns and one flash tank are used to separate cumene from otherby-products and remaining reactants. Cumene process is mainly divided into twosections: reactor section and separation section. ® Reactor section:Reactors convertscheap raw materials into desired, economical products. They play an importantrole in terms of safety and environmental protection.
A reactor is designedwith kinetics of reaction, experience, economic constraints and mostimportantly thermodynamics. For a reaction to occur, we must specify reactants,rate of reaction and products. Selection of reactor model depends on theinformation available and type of simulation. ASPEN has 7 reactors formodelling, they are: RStoic, RYield, RGibbs, RCSTR, RBatch, RPlug, REquil F. RStoicmodel can be used when the stoichiometry is known but the reaction kinetics isunknown. It can have more than one feed streams, which are mixed in the reactorto give single material-out stream.
Reactionsection consists of one reactor and two streamlines. Both reactants benzene andpropylene as liquids were fed into reactor at a temperature of 25°Cand pressure 1 bar. The temperature of the reactor has been set at 360°Cand pressure at 25 bars and there is no coolant used in the reactor C. Allthe parameters that has been considered are described in below Table 1. PROPERTIES FEED REACTOR (RSTOIC) REACT-OUT Temperature (°C) 25 360 360 Pressure (bar) 1 25 25 Mole flow rate (kmol/hr) 100 100 70.
3 Phase Liquid Vapor-Liquid Liquid Table 1: Parameters ofreaction section. All molar flow rate is in kmol/hr, temperature in °Cand pressure in bar. ® Separation section:Separationis a process of separating a mixture of substance into two or more distinctproducts.
Separation section consists of major three columns: flash tank,distillation column 1 and distillation column 2. Reactor effluent, which leavesreactor, is fed into flash tank where its temperature decreases. Propylene isnot in pure form, it contains propane as impurity, which is separated here.This stream enters distillation column 1, where we get excess benzene presentin the process. As, benzene is obtained as top product, we name it benzenedistillation column.
The bottom products then go to our other distillationcolumn, where we obtain residue (DIPB) as our bottom product which should bekept to minimum and cumene as top product is gained, which should be high.For shortcutdistillations, following models are available in ASPEN: DSTWU, Distl, andSCFrac. We have selected Distl model for our process, as it is forsingle column, free-water calculations in the condenser can be performed and itallows us to draw water streams to free water streams from condenser F. Distl model uses theapproach of Edmister, where we can separate inlet stream into two products (Topand Bottom). It is a multicomponent model, for these we must mention values offollowing parameters: 1.
Number of Theoretical stages2. Reflux ratio3. Overhead product rateHere, we can specify whether we want topartial or total condenser.
SYSOP0property method is selected for the distillation. In distillation column 1 thepressure is kept fixed at 1 bar and other parameters such as: Number of Trays,feed trays, distillate to feed mole ratio and reflux ratio have been obtainedfrom design book by Turton et al, (2003). Number of stages 20 Number of feed stages 8 Reflux Ratio 0.42 Distillate to feed mole ratio 0.67 Condenser pressure (bar) 1 Reboiler pressure (bar) 1 Table 2: Input data for Distillationcolumn 1.Inaddition, for distillation column 2, the same property method is used. Theremaining substance from distillation column 1 were fed into distillationcolumn 2.
In this column, cumene is obtained as a top product and otherresidues have been collected as bottom product, in which DIPB is main substanceand that is why this column is called cumene column. In cumene column thepressure is kept fixed at 1 bar and other parameters: Number of Trays, feedtrays, distillate to feed mole ratio and reflux ratio have been obtained fromdesign book by Turton et al, (2003). Number of stages 20 Number of feed stages 10 Reflux Ratio 0.9 Distillate to feed mole ratio 0.33 Condenser pressure (bar) 1 Reboiler pressure (bar) 1 Table 3: Input data for Distillationcolumn 1. 3.
ResultsAfterperforming simulation in Aspen Plus, results were obtained, which are mentionedin the following Table 1. This table includes data such as: molar flow rates,mass flow rates, temperature and pressure of all substances. STREAM FEED BENZENE CUMENE PROPANE RESIDUE Phase Liquid Liquid Liquid Vapour Liquid Benzene 67 27.
0938 1.96372 e-07 10.2062 6.58563 e-13 Propene 33 0.253354 0 3.04665 0 Cumene 0 10.0991 6.08641 1.
15719 12.3573 Propane 0 0 0 0 0 Total Mole Flow 100 37.4463 6.08641 14.41 12.3573 Temperature 25 79.7081 151.908 92.
5 151.908 Pressure 1 1 1 1 1 Table 1:Molar flow rates, temperature and pressure of the streams. All mole flows arein kmol/hr, temperatures in °C andpressures in bar.Theby-product propane has been separated in flash tank at a temperature of 92.5 °Cand pressure 1 bar. As shown in Table 1, propane is separated in vapour phaseat a rate of 14.41 kmol/hr.
Stream 1 containing benzene, propene, cumene andother by-products has fed into distillation column 1. In distillation column 1,benzene is separated in liquid phase by distillation process.Table1 shows temperature, pressure and molar flow rate at which benzene isseparated. The remaining components of stream 2 flow to distillation column 2,where cumene as a final product and diisopropyl benzene (DIPB) as by-producthas been distilled.
The molar flow rate of cumene and residue are 6.08641kmol/hr and 12.3573 kmol/hr respectively.Table2 and 3 represents mole fractions and mass fractions of the components.
Theoverall molar balances and mass balances of each streams have been balancedthroughout the process. STREAM FEED BENZENE CUMENE PROPANE RESIDUE Benzene 0.67 0.723538 3.22639 e-08 0.70827 5.
32936 e-14 Propene 0.33 0.00676579 0 0.211426 0 Cumene 0 0.269696 0.
999999 0.0803043 0.999999 Propane 0 0 0 0 0 Table 2:Mole fractions of the Components. STREAM FEED BENZENE CUMENE PROPANE RESIDUE Benzene 0.790305 0.
633478 2.09682e-08 0.748912 3.46352e-14 Propene 0.209695 0.00319113 0 0.120433 0 Cumene 0 0.
363331 0.999999 0.130655 0.999999 Propane 0 0 0 0 0 Table 3:Mass fractions of the streams. 4.
Conclusion Thecumene production process can be analyzed in two sections, Reactor andSeparator. The process involves trade-off between the size of reactor andreactant flow rate. Process must be designed considering initial investmentcost and operational costs which includes energy costs, raw material costs. Toimprove conversion of reactants to product cumene, we need to either provideexcess benzene or increase the size of reactor; both are expensive so dependingon the need, we must choose one. The benzene to propylene ratio was kept 2:1;this can be varied to obtain different results. Also, the by-product should bekept low as they consume our reactants.
Thehock-phenol process involves production of phenol and acetone from cumene, sowork can be carried out on that. In this process, RStoic reactor model is usedas stoichiometry of the reaction was known, reactor models such as RBatch,RCSTR and RPLUG can be used, if reaction kinetics is considered. Also, we have used benzene in excess to reduceundesirable by-products; its recycling must be done.5. References A Turton, R., Bailie, R.
C., Whiting, W. B.,Shaelwitz, J. A. Analysis, Synthesis andDesign ofChemicalProcesses, 2nd Edition, Prentice Hall, EnglewoodCliffs, NJ, 2003https://dredgarayalaherrera.
files.wordpress.com/2015/08/analysis-synthesis-and-design-of-chemical-processes3rd-ed.pdf BDouglas, J.
M. Conceptual Design ofChemical Processes, McGraw-Hill, New York, 1988.https://pdfs.semanticscholar.org/747c/a977200cbfd16a463ea790635836db603e9b.pdf CWilliam.
L. Luyben, Distillation Designand Control Using Aspen Simulation, Wiley, NewYork (2006).https://www.aiche.org/sites/default/files/cep/20060553.pdf D Nirlipt Mahapatra, Design andSimulation of Cumene Plant using Aspen Plus, National Institute ofTechnology Rourkela, 2010. http://ethesis.
pdf E Global Cumene Market Size, Cumene Market Analysis By Production (Zeolite, Solid Phosphoric Acid,Aluminium Chloride), By Application (Phenol, Acetone), By Region, And SegmentForecasts, 2014 – 2025https://www.grandviewresearch.com/industry-analysis/cumene-market FAspen Technologies, Inc, Aspen Plus UserGuide, Version 10.2, February 2000.https://web.
ist.utl.pt/ist11038/acad/Aspen/AspUserGuide10.pdf Appendix A: ASPEN PLUS Simulation ModelAppendixB: Results STREAM FEED BENZENE CUMENE PROPANE RESIDUE REACT-OUT STREAM 1 STREAM 2 Molar Enthalpy (kJ/kmol) 40021.3 33626 -10311.9 69633.8 -10311.
9 102596 15606.8 -10311.9 Mass Enthalpy (kJ/kg) 604.344 376.894 -85.
7937 942.594 -85.7938 1089.13 156.946 -85.7938 Molar Entropy (kJ/kmol-K) -213.925 -301.785 -473.
215 -151.486 -473.215 -178.34 -364.295 -473.
215 Mass Entropy (kJ/kg-K) -3.23039 -3.38252 -3.93708 -2.05058 -3.93708 -1.
8932 -3.6634 -3.93708 Molar Density (kmol/cum) 0.127062 9.
04397 6.18491 0.0328933 6.18491 0.
474904 7.98248 6.18491 Mass Density (kg/cum) 8.41437 806.892 743.391 2.
42998 743.391 44.7361 793.784 743.391 Enthalpy Flow (Watt) 1.117e+06 349770 -17434.1 278729 -35396.
5 2.0e+06 242295 -52830.5 Thereaction design reflects constraints and some consideration for future reports.Table 4 shows results which are optimized from aspen plus. It includes molarand mass entropy, density and enthalpy flow of each streams. These data arerequired to perform mathematical simulation.
Table 4:Specifications of each streams including molar and mass entropy and enthalpy,mas density and enthalpy flow.Table5 represents reactants properties of reactants that are fed in. It also showsreactor temperature, pressure, mole and mass flow rate. PROPERTIES FEED REACTOR (RSTOIC) REACT-OUT Temperature (°C) 25 360 360 Pressure (bar) 1 25 25 Mole flow rate (kmol/hr) 100 100 70.3 Mass flow rate (kg/hr) 6622.28 6622.28 4655.46 Phase Liquid Vapor-Liquid Liquid Table 5:Properties and data of the feed stream, reactor and react-out stream.