Butanol Make vs Buy Problem Statement | CHE 473K, Study Guides, Projects, Research of Chemistry

Download Butanol Make vs Buy Problem Statement | CHE 473K and more Study Guides, Projects, Research Chemistry in PDF only on Docsity! UT Design Project 2007 Butanol Make vs Buy Problem Statement ABC Acrylate Company has formed a team to evaluate the justification for the construction of a 200 kta Butyl Acrylate plant in China as part of a large integrated Olefin Petrochemical complex which is in the planning phase by the parent company. A key decision in the economic analysis of the site investment is whether to make (in-situ), or buy (externally), n- butanol as a feedstock for the Butyl Acrylate Facility. You have been assigned the task to develop an economic analysis of the Butanol supply choice. The basis for the Butanol Plant evaluation will be the Dow Low Pressure Oxo Process (LPOSM), which produces n-butanol via a 3 stage process : 1) Hydroformylation of propylene and synthesis gas to butyraldehydes. 2) Hydrogenation of butyraldehydes to crude butanol. 3) Product purification to refined to n-butanol via distillation. The Hydroformylation of propylene produces both normal and iso-butyraldehydes in an N/I ratio of approximately 10 using the LPO technology. The “iso” molecule can either be removed upstream of the hydrogenation step as a refined isobutyraldehyde product stream, or, it can be hydrogenated to isobutanol and separated during product refining. Your project analysis should develop a recommended outlet for the co-product iso-molecule. Scope of work required. Prepare a process diagram for the Butanol plant showing major items of equipment. Develop an Aspen model of the process incorporating reaction kinetics. Prepare a material & energy balance for the Butanol process. Provide a Butanol major equipment list indicating materials of construction and normal operating temperature and pressure. Estimate the total manufacturing cost ($/lb) for n-Butanol from this design. Develop an economic analysis to guide a make vs buy decision for Butanol based on the proposed Butanol plant design. Include raw material sensitivities to reflect the uncertainty of raw material price forecasting. Develop a recommended market strategy for the by-product iso-molecule, together with end-uses for other plant residue streams. Develop an economic analysis of the size and number of LPO reactors. UT Design Project 2007 Prepare a detailed Engineering Design (including Aspen Simulation) of the Isomer Distillation Column. Document the Process Safety Concerns for the process and describe how these risks will be mitigated. Conduct a Hazop on the Hydrogenation Reactor and define a basic control strategy for the safe operation of the Hydrogenation Reactor. Economic Data YEAR/COMPONENT 1 2 3 4 5 6 7 8 9 10 Chemical Grade Propylene, USD/lb 0.468 0.432 0.383 0.356 0.356 0.354 0.373 0.381 0.396 0.412 Syn Gas, USD/lb 0.170 0.167 0.161 0.160 0.159 0.158 0.160 0.163 0.165 0.169 Hydrogen, USD/lb 0.864 0.846 0.819 0.815 0.807 0.805 0.813 0.827 0.837 0.858 Purchased Butanol USD/lb (Cost & Freight SE Asia) 0.612 0.505 0.435 0.427 0.442 0.458 0.470 0.485 0.523 0.539 Isobutanol Sale Price, USD/lb (Cost & Freight SE Asia) 0.558 0.484 0.372 0.388 0.376 0.408 0.410 0.433 0.491 0.497 Isobutyraldehyde Sale Price, USD/lb 0.402 0.477 0.448 0.435 0.430 0.431 0.443 0.452 0.460 0.476 (USD =US $) Butanol/Butyl Acrylate Unit Ratio = 0.6 lbs of Butanol/lb of Butyl Acrylate A minimum of 15% DCF must be attained for any capital investment. References Oxo Process, Billig & Bryant, Kirk-Othmer Encyclopedia of Chemical Technology, John Wiley and Sons, 2001. Rhodium Catalyzed Hydroformylation, edited by Van Leeuwen and Claver, Kluwer Academic Publishers, 2002. (ISBN: 978-1-4020-0421-6). Kirkpatrick Award for Low Pressure Oxo, Chemical Engineering Magazine, 12/5/1977, page 110 (the Gas Recycle technology described in this article was a precursor of the Liquid Recycle Catalyst Technology shown below). UT Design Project 2007 Notes : 1) The following side reaction should be considered in design. Ethylene + 2 H2 + CO propanol (assume complete conversion of ethylene). 2) For details on typical Chemical Grade Components see : http://www.mrw.interscience.wiley.com/emrw/9780471238966/kirk/article/propcala.a01/current/ pdf). 2. Synthesis gas Characteristic Unit Design Value Hydrogen mol% 52.0 Carbon Monoxide mol% 47.0 Methane mol% 0.7 Carbon Dioxide mol% 0.27 Water mol% 0.03 3. Hydrogen Characteristic Unit Design Value Hydrogen mol% 90.0 Methane mol% 10.0 UT Design Project 2007 Product Specifications n-Butanol Charateristic Unit Spec Limit Butanol wt% >=99.8 Isobutanol wt% <=0.1000 DiButyl Ether wt% <=0.025 2-Ethylhexanol ppmw <=150 Total Butyrates ppmw <=50.00 Water wt% <=0.05 Color PtCo <=5 Total Carbonyl wt% <=0.005 Isobutanol Characteristic Unit Spec Limit Isobutanol wt% >=99.5 Butanol wt% <=0.1 Propanol wt% <=0.1 Water wt% <=0.05 Total Carbonyl wt% <=0.07 Color PtCo <=5 Isobutyraldehyde Characteristic Unit Spec Limit Isobutyraldehyde wt% >=99.5 n-butyraldehyde Wt% <=0.4 Water wt% <=0.05 Color PtCo <=10 UT Design Project 2007 Hydroformylation Process Steam Synthesis Gas Chemical Grade Propylene “Stabilizer” Column N-Butyrald. + heavies To Hydro- genation Purge if necessary Dissolved Gases Unreacted Feeds, Byproducts, Inerts Optional Recycle Compressor Mixed Aldes. to Hydrogenation Option #2 Hot Water Cycle Hydroformylation; Aldehyde Refining (if needed) Product Vaporizer Propylene Cleanup Bed Catalyst Recycle Product Condenser Isobutyr- aldehyde Note: Final number of reactors could be 1, 2, or 3, with or without the recycle compressor - The system can be designed as a low-conversion system with propylene recycle, or a high conversion system with more reactors and catalyst, and no recycle, or something in between. So, the size and number of CSTRs in series, and whether or not a compressor is used to recycle unreacted propylene, must be determined. Choose 2-3 representative cases and compare their economics to determine the best arrangement. Considerations should include capital cost, catalyst costs, and operating costs. - Assume the following reaction conditions for each reactor: Temperature = 95°C Pressure = 240 – 340 psig, include 20 psig drop between reactors MOC = 304 SS or 304 SS Clad Reactor volume = Catalyst must not occupy more than 3/4 of total reactor Volume Triphenylphosphine Concentration = 12 wt.% in the liquid phase of the first reactor. Hydrogen partial pressure must be at least 40 psi in each reactor vent. Carbon Monoxide must be between 5 and 15 psi in each reactor vent - Assume the heat of reaction is removed via an external heat exchanger cooled with cooling water. - Butyraldehyde trimer is a common byproduct that is not in most physical property sets. You can model “trimer” using 1-dodecanol instead (you UT Design Project 2007 Hydrogenation Process: Aldehyde Feed Hydrogen Feed Gas Cycle Compressor Tubular Reactor Feed Vaporizer Steam Heater Inerts Purge Crude Alcohol to refining Water Steam Cooling Water Condenser Catchpot Steam Heater Heavies Purge Design Assumptions: The reactor design is similar to a shell-and-tube heat exchanger, with catalyst in the tubes and water on the shell. Heat is removed by converting the water to steam. Rate, (gmoles/hr/gm unreduced catalyst) = k{Pald/(PH2)0.5} Pald = Partial press of aldehyde (psi) PH2 = Partial press of Hydrogen (psi) Ln k = -E/RT + Ln A where R= Gas Constant, T =Temp K E = 7800, Ln A = 5.31 Target Conversion: 98% Byproduct selectivities: n-Butyl n-Butyrate: 2.0 % di-n-butyl ether: 0.1% 2-ethylhexanol: 0.5 % Reactions, Kinetics, etc.: NBOHHNBAL →+ 2 , 0.954 fractional conversion of NBAL IBOHHIBAL →+ 2 , 0.954 fractional conversion of IBAL OHBUTETHERHNBAL 2222 +→+ , 0.0005 fractional conversion of NBAL 2HNBUTNBUTNBOHNBAL +→+ , 0.02 fractional conversion of NBAL UT Design Project 2007 OHEHOHHNBAL 2222 +→+ , 0.005 fractional conversion of NBAL Catalyst: Copper-based catalyst of size/shape 1/8” tablet Operating Temperature: 145 – 190°C Reaction pressure: 100-200 psig Reactor inlet composition: hydrogen / aldehyde mole ratio should be 10:1 Reactor inlet temperature should be at least 10°C above the dew point of the stream Losses of hydrogen out the “inerts purge” should be 10% of the hydrogen feed or less Heavies are purged from the aldehyde feed using the vaporizer as a single stage flash Butyraldehyde Refining: Lights Purge – Fuel Value: Propane Propylene Isobutyraldehyde Water, etc. n-Butyraldehyde + Heavies Isobutyraldehyde UT Design Project 2007 Butanol Refining: Run the columns at the lowest practical pressure above atmospheric. Heavies Purge – Fuel Value: n-BuOH Butyl Butyrate di-n-butyl ether 2-EHOH Etc. Lights Purge – Recycle to process: I Bal N Bal Water, etc. Isobutanol n-Butanol