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Steam Cracking of Ethane

CHBE 431 Final Design Presentation

James Voy

on 17 December 2012

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Transcript of Steam Cracking of Ethane

Economic Analysis Design Simulation Research The Product Ethylene Ringer M, V Putsche, and J Scahill. (2006). Large Scale Pyrolysis Oil Production: A Technology Assessment and Economic Analysis. NREL/TP-510-37779. Technical Report, National Renewable Energy Laboratory, Golden, Colorado. p 38
 Specialty Stainless Sheet & Strip. AK Steel Corporation, n.d. Web. 20 Nov 2012.
 Mohundro, E.L. "Overview on C2 and C3 Selective Hydrogenation in Ethylene." . American Institute of Chemical Engineers, n.d. Web. 2 Nov 2012.
 Cameron, G. "Process Design for the Production of." University of Pennsylvania, n.d. Web. 5 Nov 2012.
 Shi-Ping Ho, and J.A. Fisher. "Modeling and Simulation of the OiVWater." . Amoco Chemicals Corporation, 22 1977. Web. 5 Dec 2012.
 Tallman, M.J. "Naphtha cracking for light olefins." PTQ, n.d. Web. 5 Dec 2012. <www.eptq.com>.
 Maréchal, I.F. "Process integration.”. Laboratioire d’Analyse et de Synthèse des Systèmes Chimiques, n.d. Web. 1 Nov 2012.
 "Corn-Based Ethanol in Illinois and the U.S.” University of Illinois, n.d. Web. 9 Sep 2012.
 Barolo, M. "Process economics fundamentals.”. ICS Unido, 4-5 2008. Web. 29 Nov 2012. <http://www.capelab.dipic.unipd.it>.
 Hiltz, J. Design of an Ethanol Dehydration System. March Consulting Associates, Inc., n.d. Web. 10 Sep 2012.
 Seddon, D. Technology Selection in a Carbon Constrained World. Imperial College Press, n.d. Web. 15 Sep 2012.
 Turton, R. Analysis, Synthesis and Design of Chemical Processes. 4. Prentice Hall, 2012. Print.
 Perry, Robert H, and Don W. Green. Perry's Chemical Engineers' Handbook. New York: McGraw-Hill, 2008. Print. References Ethylene is one of the largest volume petrochemicals in the global market
Global demand continues to increase (average growth rate of 3% since 2000)
Expanding market for ethylene in China and India which are expected to continue to growing
90% of ethylene used for the production of other chemicals, most importantly polyethylene for plastics manufacturing
Used in packaging, insulation, and piping industries Global Ethylene Production Trends Production Resources ABC Chemical Project Goal Design a production facility which can produce 25,000 lb/hr of ethylene or the carbon equivalent of acetylene in house in order to save money on purchased proprietary plastic feedstock James Voy
Production Design Intern at Archer Daniels Midland
University of Illinois Club Volleyball Player Annie O’Neill
Project Technical Intern at Sage Environmental Consulting
Engineering Study Abroad Program in Pisa, Italy Karl Siil
Production Design Intern at Archer Daniels Midland
Enjoys home brewing Minjeong Kang
Laboratory Intern at KAIST
Foreign Exchange Student at Garrison Forest High School Major Design Decisions &
Researched Alternatives Ethane cracking results in assortment of hydrocarbon byproducts (C -C )
Focus of project is to produce ethylene
Business strategy does not involve marketing and sale of byproducts
Resultant byproducts used as fuel for fired heater, lowering natural gas utility costs
Byproducts unable to be used as fuel in small enough quantities disposed of to waste treatment Byproduct End Use Reaction temperatures near 1500 °F
High temperatures require stronger MOC
304H Alloy Stainless Steel
Melting Range: 2550-2590 °F
Greater creep and tensile yield strengths
Very low carbon content (0.04-0.1%) Reactor Material Design
Produce ethylene
Steam cracking of purified ethane feed
Coiled Tubular Reactor with fired heater
304H Alloy Stainless Steel
Usage of C byproducts as fired heater fuel
Disposal of CH , C H , and H to waste treatment Overall Decision Byproduct End Use cont. Small residence times required (10 s)
Prevents further cracking of hydrocarbon bonds
Coiled Tubular Reactor utilizes high surface area for maximized heat transfer
Coils minimize space with required reactor length
Short residence times met due to high velocity of reactor feed Pyrolysis Reactor Design Primarily used for polyethylene production
Variety of production methods and feedstocks
Can be an asphyxiating agent in high concentrations
Can be used in high pressure systems Ethylene Useful for plastic production and as welding fuel
Highly explosive (vapor pressures above 29 psi)
Expensive to store and transport due to safety concerns Acetylene Potential Product Comparison High multi-pass conversion to ethylene (81.37%)
Byproducts used best as fuel for fired heater reactor
Lower feedstock requirements (1.2 lb feed/1 lb ethylene)
More expensive due to previous cost of refining (39¢/lb ethane) Ethane Less expensive than a separated and purified feed (near 29¢/lb naphtha)
Low ethylene selectivity causing small yields (31%)
Profitability dependent on marketing of large array of byproducts
Higher fouling rate due to wide variety of hydrocarbons in feed Naphtha Feedstock Options Multiple feedstock options
Refining industry is more consistent and less affected by natural disturbances
Unreacted feed can be recycled in a continuous process
Variety of byproducts which can be sold or used for energy integration Steam Cracking of Hydrocarbon Feed Large source of local corn feed in C-U area
High yield/selectivity of ethylene (97% conversion)
Droughts or poor harvest years make corn feedstock unreliable
Impractical amount of feedstock required for large scale processes (2,500 bushels/hr) Dehydration of Ethanol from Corn Biomass Feed Ethylene Production Options It would be more
economically favorable for
ABC Chemical to continue the
direct purchase of ethylene. Final Decision

$0.63/lb Operational Expenses & COM Operational Expenses & COM Raw Materials
Ethane, propylene, DMF
Electricity, steam, cooling water, fuel gas
Waste Water Treatment
Labor Operational Expenses & COM

$123.9 million/year Ethylene Feedstock Price Land Cost: $250,000
Production Life: 15 years
Build Time: 2 years (60% FCI year 1, 40% year 2)
Discount Rate: 10%
Production: 60% in year 1, 350 days/year
Depreciation: 7 year MACRS
Total Tax Rate: 40% Economic Parameters higher production rates = more profitable

break even
sustainability, improved technology Suggestions Does not break even Cumulative Cash Flow Diagram Fixed Capital Investment Ethane Feedstock Price CapCost 2008 edition
ChemCAD sizing estimates
Validity of prices online
“Revenue” = selling price of ethylene
10% FCIL salvaged
Frequency of chemical replacement Assumptions &
Major Sources of Error ABC Chemical
Steam Cracking of Ethane Economic Analysis Operating Expenses
CCFD to meet or exceed zero
Total Project Life: 17 years Breakeven with Investment Goals $0.39/lb ethane $104 million/yr Source: ICIS Reports 2008
Operating costs per pound of
ethylene less than or equal to
price of purchased ethylene Longer Production Life Economy of Scale -3 1 5+ Acetylene and H too hot to burn in fired heater
Methane and H in distillate of de-methanizer column
Separation equipment required to purify methane and use as fuel for heater more expensive than make up natural gas
Acetylene can be hydrogenated to increase ethylene yields
Not enough C H byproduct to justify additional capital investment (0.006%) 3+ 4 2 2 2 COM Ethylene In-House: Exceeds benchmark Equipment
Flue gas control
Waste water treatment
Distillation column leaks Environmental Concerns DMF
Decompose to form emissions
Biodegrades in water & soil
Sensitive to photochemical degradation in atmosphere
Handled as hazardous waste Environmental Concerns Ethane Crackers
Release: NOx, GHG, VOCs, Sulfur Dioxide, CO
Major emission source: furnace Environmental Concerns Ethylene
Major source of HAPs
Reaction with NOx
8-hour allowable amount: 0.2 ppm Environmental Concerns Reactor
High temperature (1500°F)
High pressure
Ceramic fiber insulation Equipment Safety Concerns Process Overview Layout of the proposed plant: Process Flow Diagram Dimethylformamide (DMF)
Odorless, colorless liquid
Severe contact rating
OSHA PEL: 10 ppm Chemical Safety Concerns Distillation Columns
Large volumes
Potential for high pressures Equipment Safety Concerns Safety of the process was extremely important when considering its viability
Engineers have a responsibility to ensure the safety of the operators and surrounding community
In depth safety analysis using Piping and Instrumentation Diagrams (P&ID) was performed on the reactor and a distillation tower Safety Considerations

Three distillation towers
Acetylene absorption tower Separation and Purification

Gaseous products leaving the reactor compressed to 219 psia Compression

Fired tubular reactor
Oil Quench followed by a water quench Reactor and Quench System Pressure is a key safety
concern in a gas phase reactor
Rupture disk used as "worst case" damage control Pressure Hazard Study Ethylene
Industrial Risks: flammable, asphyxiate
Occupational Risks: low to none
Other Hydrocarbons
Stable in ambient conditions Chemical Safety Concerns Process Overview Simulation Results Simulation of Process Modeled simulation using Peng-Robinson equations of state
Pressures greater than 10 bar
Predominantly non-polar molecules
Peng-Robinson created to be applicable for all fluid components in natural gas processes Thermodynamic Model Used ChemCAD 6.5.0 to model PFD design
Simulation provided accurate estimates for equipment sizing, utility usages
Helped trouble shoot and predict potential problems with process
Acetylene absorption process
These values were organized in Excel spreadsheet to generate economic analysis of the designed process How the Simulation was Utilized Not all design data translates directly to available simulation units
Used separator to model caustic scrubbing unit
Separate fired heater and stoichiometric reaction units used to simulate coiled tubular reactor
Simulation units required additional information which needed to be found in order to obtain accurate results
Heat transfer coefficients found in Perry’s Handbook to size heat exchangers Suppositions Reactor and quench system
Separation and Purification 2 2 2 2
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