Table of Contents
CHAPTER 1 ...................................................................................................... 2 INTRODUCTION .............................................................................................. 2 1.1 Introduction .......................................................................................... 2 1.2 Physical properties ................................................................................ 2 1.3 Chemical properties ............................................................................... 3 1.4 Supply and Demand .............................................................................. 4 1.5 Production Technologies ......................... ............ .......................... .......................... .......................... ..................... ........ 6 CHAPTER 2 .................................................................................................... 11 MATERIAL AND ENERGY BALANCE ........................................................... 11 2.1 Introduction ........................................................................................ 11 2.2 Block Flow Diagram ........................................................................... 11 2.3 Material Balance ................................................................................. 12 2.4 Energy Balance ................................................................................... 16 CHAPTER 3 .................................................................................................... 20 REACTOR SIZING CONSIDERING MAIN REACTION ......................... ............ ....................... .......... 20 ............ .......................... ........................... ................ 20 3.1 Reactor Sizing According Algorithm ......................... 3.2 Catalyst Determination ........................................................................ 23 3.3 POLYMATH Result ............................................................................ 24 REFERENCES ................................................................................................ 28
CHAPTER 1
INTRODUCTION
1.1
Introduction
Ethylbenzene is an organic compound with the formula (C 6H5CH2CH3) also known as phenylethane, ethylbenzl or alpha-methyltoluene, a single ring and alkyl aromatic compound. In petrochemical industry, the aromatic hydrocarbon is important and almost exclusively (> 90%) as an intermediate in the production of styrene, which is used for making polystyrene, it is a common plastic material. In styrene production, which uses ethylbenzene as a starting raw material, consumes ca. 50% of the world’s benzene production. Less than 1% of the ethylbenzene produced is used as paint solvent or as an intermediate for the production of diethylbenzene and acetophenone. (Ullmman''s, 1985)
CHAPTER 1
INTRODUCTION
1.1
Introduction
Ethylbenzene is an organic compound with the formula (C 6H5CH2CH3) also known as phenylethane, ethylbenzl or alpha-methyltoluene, a single ring and alkyl aromatic compound. In petrochemical industry, the aromatic hydrocarbon is important and almost exclusively (> 90%) as an intermediate in the production of styrene, which is used for making polystyrene, it is a common plastic material. In styrene production, which uses ethylbenzene as a starting raw material, consumes ca. 50% of the world’s benzene production. Less than 1% of the ethylbenzene produced is used as paint solvent or as an intermediate for the production of diethylbenzene and acetophenone. (Ullmman''s, 1985)
ingestion, respiratory effects such as throat irritation and lung constriction, irritation to the eyes and skin adsorption. The physical properties of ethylbenzene are as follows (Ullmman''s, 1985) : Table 1.1: Physical properties of Ethylbenzene No.
1
Density
2 3
Melting Melting Point Boiling Boiling Point
4
Refractive Index
5 6 7 8
Critical Pressure Critical Temperature Temperature Flash Flash Point Point Auto Ignition Ignition Temperature Temperature
9
Flammability Limit
10
Latent Heat
Properties At 15 C At 20 C At 25 C
At 101.3 101.3 KPa At 20 C At 25 C
lower upper fusion
0.8713 0.87139 9 g/cm g/cm 0.8669 0.8669 g/cm g/cm 0.86 0.8626 262 2 g/cm g/cm -94.949 -94.949 C 136.186 136.186 C 1.4958 1.49588 8 1.4932 1.49320 0 3609 KPa 344.02 344.02 C 15 C 460 C 1.0% 86.3 J/gm
temperature (600-6600C) usually over an iron oxide catalyst. Steam is used as diluents. Commercially, selectivity’s to styrene range from 89 to 96% with per -pass conversions of 65-70%. The production by products is reduced if the temperature is gradually lowered during the course of the reaction. The hydro peroxide is subsequently reacted with propene in a process that yields styrene and propylene oxide as co products. With suitable catalyst, it can be converted to xylenes. Commercially processes for isomerising xylenes usually involve the catalytic isomerisation or dealkylkylation of Ethylbenzene. Like toluene, it may be dealkylated catalytically or thermally to benzene. It is also undergoes other reaction typical of alkyl aromatic compounds. (Vincent AVincent A.Welch, 2005)
1.4
Supply and Demand
We have mentioned that ethyl benzene is a colourless liquid with a gasoline
Ethyl Benzene were so high that will give benefit to the industry to produce more product that were linked to Ethyl Benzene. This shows that the Ethyl Benzene (EB) is quite an important chemical product that has a lot of uses to the industry. Based on analysis, The Asia-Pacific is the biggest market of benzene consuming a significant share of the total consumption in 2012, and it is also the second fastest growing market next to ROW. The consumption patterns of benzene and its various derivatives are continuously showing an upward trend which is mainly due to the shift of manufacturing industry to the Asia-Pacific on account of increasing demand and low cost of production. China is the leading country in the region in terms of both, production as well as consumption of benzene and its derivatives, while the Indian market, despite being small in size, is expected to be a market with high potential (PRNewswire , New York, June 19, 2014).
For instance, global demand for ethyl benzene amounted to 28,567,852 tons in 2014 (BGI research, 2012). The global EB market was dominated by the AsiaPacific region, with the domestic markets in developing economies expanding exponentially (Global Chemical Price, 2013). The increasing standard of living and increased styrene capacities across the globe increased the usage of EB in a number of countries. With demand recovery expected in developed markets and increasing demand expected from developing economies, overall global EB demand is expected to have reached 34,667,874 tons by 2020 (GBI Research, 2012). Figure 1.2 shows global demand trends for EB in volume terms from 2000 to 2020.
1) Liquid phase aluminum chloride catalyst process 2) Vapour-phase zeolite catalyst process 3) Liquid phase zeolite catalyst process 4) Mixed Liquid-Vapour Phase zeolite Catalyst process
1.5.1
Liquid Phase Aluminium Chloride Catalyst Process
This is the first process used in producing of ethylbenzene since 1930’s. Alkylation of benzene with in the presence of an aluminum chloride catalyst complex is exothermic (_H-114 kJ/mol); the reaction is very fast and produces almost stoichiometric yields of 7thyl benzene. In addition to AlCl3, a wide range of Lewis acid catalysts, including AlBr3, FeCl3, and BF3, have been used. Aluminum chloride processes generally use ethyl chloride or hydrogen chloride as a catalyst promoter. These halide promoters reduce the amount of AlCl3 required.
1.5.4
Mixed Liquid-Vapour Phase zeolite Catalyst process
The CDTECH process is based on mixed liquid-vapour phase alkylation reactor section. The design of commercial plant is similar to the liquid phase technologies except for the design of the alkylation reactor which combines catalytic reaction with distillation into a single operation. Table 1.2: The Comparison for Production Technology of Ethylbenzene. (Shenglin Liu, March 2009)
Properties Operating Temperature Operating Pressure Conversion Phase
Catalyst
Advantages
Liquid Phase Aluminium Chloride Alkylation
Vapour-phase Zeolite Alkylation
Liquid phase Zeolite Alkylation
400-450 C
450° to 600° C.
Mixed Liquid-vapour phase Zeolite Alkylation
2-3 MPa (20-30 bars). 99% Three phase are present ; Aromatic liquid, ethylene gas, and a liquid catalyst complex phase Aluminium Chloride catalyst complex i. The aluminium chloride present in alkylation reactor effluent catalyst trans alkylation reaction. ii. Reaction is very
100% The high-activity catalyst allows transalkylation and alkylation to occur simultaneously in a single reactor
100%
100%
The alkylation reactor is maintained in liquid phase
Mixed liquid-vapour phase
Zeolite Catalyst
Zeolite Catalyst
Zeolite Catalyst
i. Use of zeolite catalyst that eliminated issues associated with corrosion and waste disposal of aluminium chloride ii. The original vapour phase design accomplished the
i. The liquid phase zeolite catalyst process operates at substantially lower temperature decreased side reactions dramatically resulting in ultra-high purity
i. Combines catalyst reaction with distillation into single operation ii. The exothermic heat of reaction creates vaporisation necessary to
fast in presence of Aluminum chloride &produces almost stoichiometric yields of Ethylbenzene. iii. Essentially 100% of ethylene is converted
alkylation and trans alkylation reactions in single reactor iii. The third generation technology is capable of achieving EB yield greater than 99% iv. The third generation technology offered significant benefits in purity ,capital cost
i. Handling and i. The significant extent of disposal of aluminium isomerisation reactions and chloride catalyst and waste catalyst deactivation by has become increasingly deposition of carbonaceous more costly and material are most important complicated because of problems associated with high environmental temperature considerations ii. The length of time Disadvantages ii. Equipment and between regeneration can vary piping corrosion and from as little as 2 months to fouling along with related slightly more than 1 year environmental issues led depending on specific plant to development of EB design and operating conditions process based on solid iii. Because the reactors acid heterogeneous must be taken off line for catalysts regeneration ,on-stream
EB product ii. The plant achieve high on stream efficiency often greater than 99% which results in low turnaround & maintenance cost iii. EBZ-500 catalyst has operating length of more than 8year without catalyst regeneration iv. The regeneration is mild carbon burn procedure that is relatively inexpensive
effect distillation iii. Capable of using dilute ethylene feed e.g. Off gas from a fluid catalytic cracking plant or dilute ethylene from steam cracker iv. In general ethylene feed streams containing significant amounts of hydrogen, methane or ethane do not require some pretreatment. (David Netzer, 1999)
Do not have disadvantage
iii. Major equipment efficiency can be low resulting pieces needed to replace in high operating costs for on regular schedule vapour phase plant because of corrosion iv. Additional equipment which results in extensive may be required for regeneration turnarounds poor plant on- procedure depending on specific stream efficiency and thus plant design which adds capital are primary contributors to cost to plant the high operating costs associated with aluminium chloride
From above advantages & disadvantages for different processes we select Vapour Phase Zeolite Catalyst process (UOP). Since it has more advantages over other existing manufacturing process for Ethylbenzene. Not only that, it also have long catalyst run-length with excellent stability which can minimizes plant downtime, and It has highly selective reaction that are insignificant amount of xylenes are produced, providing a highest product quality. Also it requires less pure benzene & ethylene. Less harm full to environment also. (technology, 2012)
CHAPTER 2
MATERIAL AND ENERGY BALANCE
2.1
Introduction
This chapter will focus on calculation of material and energy balance for production of 40,000 MT of Ethylbenzene. The reaction kinetics of EB production is as follows. The production of ethylbenzene (C 6H5C2H5) takes place with the direct addition reaction between ethylene (C2H4) and benzene (C6H6). C6H6 + C2H4 C6H5C2H5
----- (1)
However, there is another inevitable reaction takes place at the same time as reaction (1) which is to produce diethylbenzene (C 6H4(C2H5)2), an unwanted product.
Figure 2. 1: Input-output structure of reactor of Ethylbenzene plan
2.3
Material Balance
As this is mini project for Chemical Reaction Engineering II, we will consider
The capacity of the plant producing commercial grade ethylbenzene is 40,000 metric tonne per year and it has been assumed that the plant operates 8000 hours per year with about 32 days for shutdown, maintenance and troubleshooting. The basis of production of ethylbenzene per day will be used.
----- (4) From Equation (4), 5000 kg of Ethylbenzene will be produced per hour. The assumption of calculation are listed as follows;
Pure benzene and ethylene
All gases behave ideally
Yield is 99.99%
90% conversion of ethylene (limiting reactant) to ethylbenzene & diethylbenzene
Ethylene outlet from the reactor, FE = F FE + (1-X) = PEB/YX * (1-X) = 47.09/0.99 (0.9) * (1-0.9) n3
= 5.29 kmol/hour
Benzene For PEB, n5
=ζ=
= 47.09 kmol/hour
For benzene inlet into the reactor, = PEB/Y+FE (3 – X)
The results of calculations are tabulated as in Table 2.3. It is shown from total of mass balance, the calculation is considered balanced. Table 2.3: Summary of Mass Balance.
Species
Inlet (kmol/hour)
Outlet (kmol/hour)
Inlet (kg/hour)
Outlet (kg/hour)
Benzene Ethylene Ethylbenzene Diethylbenzene Total
158.55 52.85 0 0 211.4
110.99 5.29 47.09 0.53 163.9
12384.3405 1482.4425 0 0 13866.783
8669.4289 148.3845 4999.5453 71.1366 13888.4953
2.4
Energy Balance
In this part, only energy balance in the packed bed reactor will be calculated accordingly. Figure 2.2 shows input-output structure of temperature in the said reactor, where temperature feed is at 298K, while the temperature outlet is 573K. The reactor operates at 573K and 5000 kPa.
Figure 2.3 shows structure of enthalpy path of reaction from 298K to 573K, where ∆H is enthalpy change of the reaction, ∆H°rxn is heat of reaction of benzene and ethylene to ethylbenzene at 298K and ∆HP, 1 denotes enthalpy change of ethylbenzene from 298K to 573K.
Figure 2. 3: Enthalpy structure for energy balance
∑ From equation above, ∆H°rxn = 29920 – 82930 – 52510 ∆H°rxn
= -105520 J/mol
The heat of reaction is calculated by using formula;
∫ The heat of reaction of Benzene from 298 K to 573 K
C6H6 = 3904.97 J/mol
To find the total heat of reaction Total, ΔH
= ∆H°rxn + ∆HP,1 = -105520 +11729.63 = - 93, 790.37 J/mol
Since alkalynation of ethylbenzene is exothermic reaction, the heat of reaction calculated have negative value indicated it is in exothermic reaction.
CHAPTER 3
REACTOR SIZING CONSIDERING MAIN REACTION
3.1
Reactor Sizing According Algorithm
The reactor is determined to packed bed reactor. Manually, calculation is done by following the algorithm as studied. Recall the reaction,
Mechanism, Adsorption:
[ ] Site balance,
substitute (1),(2),(3)and (5) into (4)
[ ]
) ( ) ( ) (
( )() ( )() ( )() Where
4 6.344 X 10 3 2 6 k 1 [kmol/m cat/h/atm ] 0.69 10 exp RT
K A
K B
162 ,730 RT
[atm -1 ] 1.2328 10 17 exp
35,368 RT
[atm -1 ] 2.0850 10 4 exp
Stoichiometry
Combine
FAO = 158.55 kmol/hr
gc
= 32.174 lb m.ft/s2.lbf = 4.17 x 10 8 lbm.ft/h2.lbf
µ
= 2.71 x 10-5 Pa.s = 0.06556 lb m/ft.h
= 0.7 kg/m3 = 0.0437 lbm/ft 3
= u = 1.21067 kg/m 2.s = 0.8927 lbm / ft2.h
G
Therefore,
POLYMATH Report
No Title 30-Dec-2014
Ordinary Differential Equations
Calculated values of DEQ variables Variable Initial value Minimal value Maximal value Final value 1
A
3.482E-06
3.482E-06
3.482E-06
3.482E-06
2
E
-0.1666667
-0.1666667
-0.1666667
-0.1666667
3
Fao
158.55
158.55
158.55
158.55
4
k1
1.136199
1.136199
1.136199
1.136199
5
Ka
0.0084311
0.0084311
0.0084311
0.0084311
6
Kb
0.3494354
0.3494354
0.3494354
0.3494354
7
Kc
-3.949E-06
-3.949E-06
-3.949E-06
-3.949E-06
8
Pa
5000.
0
5000.
0
9
Pao
5000.
5000.
5000.
5000.
10 Pb
2.5E+04
2.372E+04
2.5E+04
2.372E+04
11 Pc
0
0
5993.528
5928.934
12 R
8.314
8.314
8.314
8.314
13 r1
-1.842766
-1.842766
0
0
14 rT
-1.842766
-1.842766
0
0
15 T
573.
573.
573.
573.
16 W
0
0
8100.
8100.
14 A = 3.482*10^(-6) alpha
15 rT = r1
General Total number of equations
17
Number of differential equations 2 Number of explicit equations
15
Elapsed time
0.000 sec
Solution method
RKF_45
Step size guess. h
0.000001
Truncation error tolerance. eps 0.000001
W 0 22.95491 40.55491 49.35491 58.15491 66.95491 84.55491 93.35491 102.1549 110.9549 128.5549 137.3549 146.1549 154.9549 172.5549 181.3549 190.1549 198.9549 216.5549 225.3549 234.1549 242.9549 260.5549 269.3549 278.1549
X 0 0.2396088 0.3891483 0.4539301 0.5126204 0.565648 0.656403 0.6949469 0.7294536 0.7602877 0.8122901 0.8340773 0.8534292 0.8705981 0.8992874 0.9112068 0.9217439 0.9310528 0.9465244 0.9529215 0.9585615 0.9635323 0.9717691 0.9751658 0.9781561
X calc 0.767278907 0.774224554 0.779549923 0.782212608 0.784875292 0.787537977 0.792863346 0.795526031 0.798188713 0.800851397 0.806176767 0.808839451 0.811502136 0.814164821 0.81949019 0.822152875 0.82481556 0.827478244 0.832803614 0.835466298 0.838128983 0.840791668 0.846117037 0.848779722 0.851442406
X residual 0.767278907 0.534615754 0.390401623 0.328282508 0.272254892 0.221889977 0.136460346 0.100579131 0.068735113 0.040563697 -0.006113333 -0.025237849 -0.041927064 -0.056433279 -0.07979721 -0.089053925 -0.09692834 -0.103574556 -0.113720786 -0.117455202 -0.120432517 -0.122740632 -0.125652063 -0.126386078 -0.126713694
X residual ^2 0.588716922 0.285814004 0.152413427 0.107769405 0.074122726 0.049235162 0.018621426 0.010116162 0.004724516 0.001645414 3.73728E-05 0.000636949 0.001757879 0.003184715 0.006367595 0.007930602 0.009395103 0.010727689 0.012932417 0.013795724 0.014503991 0.015065263 0.015788441 0.015973441 0.01605636
REFERENCES
David Netzer, 1. H. (1999). "Mixed Phase Ethylene Process for Manufacturing Ethylbenene". U.S.Patent , 977,423. ICIS . (2011, August). Retrieved from Ethylbenzene (EB) Prices and Pricing Information: http://www.icis.com/resources/news/2007/11/02/9075692/ethylbenzene-eb-pricesand-pricing-information/ iHS Chemical . (2012, October). Retrieved from http://www.ihs.com/products/chemical/planning/ceh/ethylbenzene.aspx Klaewkla, R., Arend, M., & Hoelderich, W. F. (2011). A Review of Mass Transfer Controlling the Reaction Rate in Heterogeneous Catalytic Systems. InTech. Petronas. (2014). Retrieved from http://www.petronas.com.my/our business/downstream/petro-chemicals/Pages/other-petro-chemical-plants.aspx Polimeri Europa. (n.d.). Retrieved from http://www.eni.com/it_IT/attachments/azienda/attivita-
