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1、AIChE 2008 National Student Design CompetitionCoal to Methanol Chemical Plant ReportChi Hang LeeMan Kit ChanChan Yau AoUniversity of California, San DiegoDepartment of Mechanical and Aerospace EngineeringChemical Engineering Program9th June, 2008Professor Pao ChauContentsExecutive Summary .1Overall
2、Project Scope Description .1Design Basis, Principle and Limitations .2Technology Selection Criteria and Conclusion.5Process Performance Summary .9Project Economics Summary .17Project Description .18Process Flow Diagram .19Major Equipment and List .21Environmental and Process Safety .21Appendix A: Co
3、al Input Calculations Appendix B: Higman Gasification Simulation OutputAppendix C: Water Gas Shift Reaction CalculationsAppendix D: Methanol Synthesis Rate CalculationsAppendix E: Temperature vs. CO2 and H2S with NMPAppendix F: NMP Cost CalculationAppendix G: ASPEN Input FileAppendix H: ASPEN Simula
4、tion Appendix I: Equipment Sizing Calculation1. Goal Gasifier 2. Acid Gas Removal Tower3. Water Gas Shift Reactor4. Flash Drum 5. Distillation Tower 16. Distillation Tower 2Appendix J: Economic Analysis for PFRAppendix K: CAPCOST ModelAppendix L: Overall Process Flow DiagramExecutive SummaryAs the p
5、rice of crude oil continues to increase, there is a raising need to produce an alternate fuel source Methanol is an attractive contest and in this project, the economic feasibility and a preliminary design for a chemical plant to produce methanol to coal is explored. Design will be completed with th
6、e computer model ASPEN, while the economic is carried out utilizing CAPCOST. The desired output of methanol is 5000 MT/day and must also meet the AA grade requirement. This preliminary design is capable of producing 5065 MT/day of methanol, the plant is designed based on 292 days per year and 24 hou
7、rs operation schedule. The internal rate of return on investment is 0.13% and a paid back period of 19.3 year. Overall Project Scope DescriptionThis study serves to provide a preliminary design for a coal-to-methanol process and to determine the economic feasibility of the project. Location of the p
8、lant has been decided to be on the US Texas Gulf Coast, and a capacity to produce 5000 MT per day of methanol is desired. Methanol produced must meet the AA methanol grade purity specification. The process will start by selecting a coal source out of three types of coal. It is assumed that the selec
9、ted coal has been pre-processed at an estimated cost and transferred into a gasifier in which coal is reacted with steam and oxygen producing a syngas containing unreacted steam, H2, N2, CH4, H2S, CO2, CO and NH3. The syngas will then be subjected to a separation unit for acid gas removal. The H2S c
10、oncentration in the treated syngas will be reduced to less than 0.1 ppmv before entering the water gas shift reactor. In the water gas shift reactor, the stoichiometric ratio between H2 and CO in the clean syngas is shifted to the desired ratio of 2:1. This specific ratio is needed to favor the prod
11、uction yield of methanol in the methanol synthesis process which consists of a series of five adiabatic plug flow reactors with inter-stage cooling systems. The methanol produced will then be refined in order to meet the specific AA grade requirement. The overall process of the design is presented i
12、n Fig.1 below.Fig. 1.Block flow diagram of coal-to-methanol process.Methanol produced can be sold at a price of $320/MT (US Gulf Coast FOB). An economic analysis of the coal-to-methanol process will also be performed to evaluate the economic feasibility of the plant. Key numbers such as capital cost
13、, operating cost, project internal rate of return (IRR), sensitivity of the project economic and payback period will all be considered when determining the overall economic feasibility. Besides, the environmental and safety of the methanol production plant will also be analyzed and considered when e
14、valuating the environmental feasibility of the design. Design Basis, Principles and LimitationsCoal GasificationVarious calculations in this design are performed using MT/day as the basis. In the coal gasification process, the governing chemical reactions can be generalized as the following reaction
15、:CxHy + x/2 O2 xCO + y/2 H2(1)Since the gasifier operates at high temperature (in excess of 1500 C)and pressure (3200 kPa), it can be modeled as equilibrium reactors assuming near-complete carbon conversion using the following set of reactions: CO + H2O CO2 + H2(2)C + CO2 2 CO(3)C + H2O CO + H2(4)These reactions are assumed to at therm
