Presented By:
B. Rajasekhar
Ch.Madhubabu
M. Ramya
N.Ganesh varma

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LIQUID PHASE CATALYSIS OF MtBE USING SULFURIC ACID AS CATALYST
 Problem statement
 The purpose of this project is to determine the feasibility of constructing a chemical plant to manufacture 1,00,000 ton/y of MTBE by liquid phase catalysis of methanol and isobutylene using sulfuric acid catalyst.
 Both methanol and isobutylene are pure and available from natural gas and refinery cuts respectively.
 This project includes
Simulation of flowsheet using chemcad- Simulation of PFR using MATLAB (or) spreadsheet.
Specific equipment design for Heatexchanger Preliminary cost estimation and Plant design &layout.
INTRODUCTION
 MTBE(methyl tertiary butyl ether) belongs to oxygenates family eg: ethers, alcohols.
 It is a gasoline additive that boosts the oxygen content of gasoline which is also called as “an octane enhancer”.
 Results in significant reduction in air pollution from vehicle exhausts as it replaces TEL and TML.
 Can be used in concentrations on average of 8-10 weight % in gasoline.
history
 MTBE production started and shooted up between 1970 -1999 in US since the phase out of ‘lead’ in1970.
 US EPA ordered to stop its production in 1999 due to ground water contamination and to replace with ethanol.
 But EU of MTBE ,Europe studies concluded that
It does not pose danger to human health but tight controls are required on handling and storage .
US EPA studies might be faulty.
 In Europe production approximately equals the demand and firmly stable in next few years.
 8 Asian countries like Japan, China etc already phased out lead and started MTBE production. INDIA is in progress
COMMON NAMES AND STRUCTURE
 Chemical Name: 2-methoxy-2- methyl-propane (IUPAC)
 Chemical Family: Alkyl ethers
 Form: At room temperature it is a highly volatile, flammable and colorless liquid.
 Common Names: MTBE
Methyl tert-butyl ether
tert-Butyl methyl ether
 CAS# : 1634-04-4
 Formula: C5H12O
Chemical Structure:
 physical ,chemical and thermal properties of mtbe
 Molecular weight : 88.15
Elemental analysis
Carbon content, wt% : 68.1
Hydrogen content, wt% :13.7
Oxygen content, wt% :18.2
 C/H ratio :5.0
 Density, g/cc
at 25° :0.7352
at 30°C :0.7299
 Reid vapor pressure
at 25°C, psi- : 7.8
 Boiling point, °C :55.0
 Freezing point, °C : -108.6
 Critical properties:
temperature(Tc),°K: : 510
pressure (Pc) ,Pa :3.31*e5
volume(Vc),m3\kmol :0.329
 Solubility of MTBE in water at 25°C, wt%: :<5
 Viscosity at 37.8°C, cSt :11.7
 Refractive index at 20°C :1.3694
 Surface tension, din/sqrcm :19.4
 Latent heat of vaporization
at 25°C, Cal/g :81.7
 Specific heat at 25°C, Cal/g°C :0.51
 Flammability limits in air
Lower limit, vol% :1.5
Upper limit, vol% :8.5
 Auto ignition temperature, °C :425
 Flash point, °C : -30
 Blending octane number
RON :117
MON :101
(RON+MON)/2 :110
applications
 90% of total production of MTBE is used as an antiknocking agent.
Remaining 10%
 To produce highly reactive polyisobutylene, butylrubber, methylmethacrylate.
 As a solvent replaced with diethyl ethers to improve the miscibility of other solvents.
 In clinical medicine to dissolve the cholesterol gall stones.
 Advantages of mtbe over other OXYGENATES
 Other oxygenates are
Ethers: TAME,TAEE,ETBE,
Alcohols: ethanol, methanol.
 Ethers have comparatively:
 low RVP
 low vaporization temperature
 low flame temperature and
 high octane number.
 Among ethers MTBE is proven to be economically effective as its physical, chemical properties are compatible with gasoline especially its boiling range.
 Higher octane number than other ethers.
 Literature survey
 There are three types of MTBE production plants:
 Refinery/Petrochemical plants: uses Isobutylene, produced as a byproduct in refinery catalytic crackers.
 Merchant plants: Merchant plants uses normal butane to isobutane, dehydrogenate isobutane to isobutylene
 TBA plants: TBA plants uses tertiary butyl alcohol (TBA) as a byproduct of the propylene oxide production process.
 Another raw material is methanol for all plants
 Comparison of the processes
 Selection of the process
 Refinery plants are proven to be least expensive which can also work on less purity raw materials.
 Operated in only liquid phase with either solid or liquid phase acid catalysts.
 Chemical reaction and kinetics
 Pfr conversion with length
 process Flowsheet
 Material balances
 Basis :100,000 ton/y of MTBE with on-stream factor of 0.9.
 Reactants mole ratio (CH3OH to C4H8):- 1.1
 Product in kmol/h : 100,000*1000/(328*24*88.15)=144.1
 Feed requirements to produce 144.1kmol/h of mtbe:
 C4H8 == 162.46 kmol/h (144.1/0.895)
 CH3OH == 178.7 kmol/h (1.1*162.46)
 Sulfuric acid== 7.57 kmol/h (5wt% of reaction mixture)
 Molecular weights(kg/kmol):
C4H8: 56.1
CH3OH: 32.04
Sulfuric acid: 98
MTBE: 88.15
 Material balance equipment
 Reactor
 Separator 1
 Washer
 Separator 2
 Distillation column 1
 Distillation column 2
 Mixers-1,2,3
 Reactor mass balance
Conversion= 89.5%
1 mole of isobutene requires 1mole of methanol to produce 1mole of product(from reaction stoichiometry)
SEPERATOR-1 MASS BALANCE
Total mass flow rate in = 15623.37kg/h
Total mass flow rate out=741.59+14881.78 = 15623.78kg/hr
IN RATE = OUT RATE
Sulfuric acid recovery= 97% and methanol=2% from bottom
WASHER MASS BALANCE
Total mass flow rate in= seperator1 top+ fresh water in=
= 14881.78+594.495=15476.28 kg/hr
Total mass rate out= 15476.28 kg/hr
 Seperator-2 mass balance
 99.8% of MTBE 100% of isobutene is removed from the top. Water and methanol from the bottom.
 Total mass in =15476.28 kg/hr
 Total mass out = 13832.88+164.398=15476.28 kg/hr
 Distilation column-1
 Distillate purity xd = 91.05%
 bottom product purity: 99.97%
 Total feed= 13832.8 kg/hr outlet=D+B=13832.8 kg/hr
 Distillation column 2
 Total feed (SEP 2 bottoms),F =1643.398 kg/hr
 Dstillate purity.xd= 0.9977,
 Feed F = 1643.398 kg/hr =(D+B)= (1024.618+618.772)kg/hr
 mass balances of mixer 1,2,3.
Mixer 1:
 Inlet streams: fresh methanol + recycle stream from distillation column 2: 4657.9468+1024.61 =5682.07 kg/hr
 Outlet stream flow rate =5682.07 kg/hr.
Mixer 2:
 Inlet streams= mixer1 outlet +fresh isobutene+ recycle stream from distillation column 1: =5682.08+8153.845+1023.43 =14859.36 kg/hr
 Outlet flow rate =14859.36 kg/hr
Mixer 3:
future implementation
 Energy balances
 Simulation of PFR
 Specific equipment design
 Plant location and layout
 Health and safety factors
 Preliminary cost estimation etc