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Introduction:
Acrylonitrile, first synthesized in 1893 by Charles Moureu, did not become important until
the 1930s, when industry began using it in new applications such as acrylic fibers for textiles
and synthetic rubber. Although by the late 1940s the utility of acrylonitrile was
unquestioned, existing manufacturing methods were expensive, multistep processes. They
seemed reserved for the world's largest and wealthiest principal manufacturers: American
Cyanamid, Union Carbide, DuPont, and Monsanto. At such high production costs,
acrylonitrile could well have remained little more than an interesting, low-volume specialty
chemical with limited applications. In the late 1950s, however, Sohio's research into
selective catalytic oxidation led to a breakthrough in acrylonitrile manufacture.
Overcapacity had been a problem for ACN markets but they are now much better balanced
due to plant closures brought about by poor demand and surging feedstock costs. In
general, plant closures have exceeded capacity additions with ACN supply becoming tight to
balance. There has also been a shift in capacity from North America to Asia.
As far as the demand is concerned, global demand for ACN is only expected to grow by 1-
2%/year, with strongest demand in Asia pulled by the growth in ABS.
World annual production of Acrylonitrile in 2001 was 4 million tonnes and in 2008, 6.2
million tonnes, with just under half of that coming from the United States.
The present plant under operation in India is Indian Petrochemical Corp. Ltd, Gujarat.
Problem Statement:
In examining the steps commonly practiced in designing a chemical product or process, it is
important to keep in mind that design problems are open ended and may have many
solutions that are attractive and near optimal.
The design team needs to design a process for production of 50000 Tonnes per annum of
Acrylonitrile as the product.
Choose the optimal pathway for your process (appendix) considering techno economic
feasibility and environmental factors. You are provided with information of availability and
cost of raw materials and three sites for construction of plant (appendix). Using different
parameters like prosperity, profitability and productivity (appendix) select your plant
location. Come up with a legitimate Process Flow Diagram (PFD) of the process chosen and
perform “design and sizing of reactor”.
Rules:
Submission format:
Process selection: Explain using “Techno economic feasibility sheet”
Document explaining site selection
PFD of the selected process using software like Microsoft visio with proper
labeling of temperature and pressure.
Explanation of the Process flow diagram (PFD)
Explain the type of reactor used and Sizing of the reactor for the process.
Submission deadline for stage 1 is 25th February, 2013
Appendix:
Reaction Pathways
1. From Acetylene and Hydrogen Cyanide:
N
Hydrogen CyanideAcetyleneN
Acrylonitrile
+
Temperature: About 80 degC.
Pressure: 2-3 psig
Catalyst: CuCl in HCl
2. From Acetaldehyde via Lactonitrile:
N
Hydrogen Cyanide
OAcetaldehyde
OH
N
Lactonitrile
N
Acrylonitrile
Phosphoric acid
+
Temperature: 650 for dehydration
Pressure: 1 atm
Catalyst: 10% NaOH for 1st step & H3PO4 for dehydration
3. From Ethylene Oxide:
Lactonitrile
NHydrogen Cyanide
O
Ethylene Oxide
+N
OH
Ethylene CyanohydrinN
Acrylonitrile
Temperature: 55 – 60 for the 1st step and 200 for dehydration
Pressure: 1 atm
Catalyst: Diethylamine for the 1st step and alumina for liquid phase dehydration
4. From Propylene and Nitric Oxide:
+4 6 6N
Acrylonitrile
+ H
O
H
WaterPropyleneNO
Temperature: 450 – 550
Pressure: 1 atm (higher pressures give better yield )
Catalyst: Silica based or Lead and Thallium based
5. From Acrolein:
Temperature: 350-550
Pressure: 1 atm
Catalyst: Mixture of oxides of Sn and Sb, they being in a ratio of 0.1 – 10
6. Ammoxidation of Propylene:
N
Acrylonitrile
H
O
H
WaterPropylene
NH3+ 1/2 O2+ 3+
Temperature: 400-500
Pressure: 0.3-2 bar (gauge)
Catalyst: Several possibilities
7. From Propane:
Temperature: 485 – 580
Catalyst: Sb based
Appendix 2
The entire site selection exercise can be divided into three main factors:
Profitability factors
o Land
o Climatic Conditions
o Raw Material Source and Product Market
o Utilities
o Environmental Aspects
o Housing
o Transport to Staff
o Equipment Transportation
o Statutory Duties and Taxation
Productivity factors
o Communication
o Industrial Infrastructure
o Housing/Hotels
o Civic Amenities
o Labor
o Transport