Abstract PEP Review 2012-10 ETHYLENE GLYCOL PRODUCTION FROM COAL-BASED SYNTHESIS GAS By Syed N. Naqvi and R. J. Chang (October 2012) ABSTRACT This review presents a technoeconomic evaluation of a newly commercialized monoethylene glycol (MEG) production route, which, if it successfully meets the desired level of product purity and catalyst stability, could revolutionize the MEG industry with the possibilities of switching its production from the current ethylene-based source to a new coal-based source. At the moment, this route is only commercialized in China, mainly because of its rich coal resources and high ethylene prices. The technical review presented here is based on a study of about twenty-seven patents of Chinese companies and institutes (listed inside). The process design and plant economics worked out therefrom are, however, based upon the information provided by the Fujian Institute of Research on the Structure of Matter (Chinese Academy of Sciences) in its patents (CN1054765A, CN1148589A, and CN102247847A). Six plants based on Fujian technology, each at 200 thousand t/yr capacity, are under construction. The owners of these six plants are Henan Coal Chemical Group Co. Ltd. and Tongliao GEM Chemical Co. Ltd. The process essentially consists of several stages of reaction and resulting products separation. In the initial step, CO and methyl nitrite (CH 3 ONO) react in the gaseous phase in the presence of a proprietary Pd catalyst, producing a mixture of dimethyl oxalate (CH 3 COOCOOCH 3 ) and nitric oxide (NO). The two reaction products are separated from each other by condensing dimethyl oxalate in a methanol-scrubbed column. Nitric oxide, along with unconverted CO and other associated light gases, leave the scrubbing column in gaseous form. In the second step, nitric oxide formed in the first step is converted back to methyl nitrite by reacting with methanol and oxygen. Water is also formed in this reaction. The reaction takes place in a countercurrent gas-liquid column, with nitric oxide and oxygen entering from the bottom and methanol spraying down the column from the top. The light gases (mainly unconverted NO), unconverted O 2, CO, CO 2, N 2, etc., leaving from the top of the column are cooled, and after purging a small portion thereof, recycled to the first-stage dimethyl oxalate reactor. An aqueous solution of methanol is removed from the bottom of the column. The third reaction step consists of converting dimethyl oxalate to ethylene glycol (EG) in an excess of H 2. Methanol for producing methyl nitrite is also regenerated in this reaction. This is a vapor-phase process in which a proprietary type of copper-zinc chromite is used as a catalyst. Some impurities/by-products such as methyl glycolate, dimethyl carbonate, methyl formate, 1,2- butanediol, etc., are also produced in small amounts. While most of the impurities are removed from the EG without serious difficulties, 1,2-butanediol is likely to pose a problem for producing fiber-grade EG. Product separation and refining (of EG) is done through a series of distillation columns. The process economics of a stand-alone as well as an integrated (with coal gasification/syngas) EG plant are presented in this review. 2012 IHS PEP Review 2012-10
A private report by the Process Economics Program Review No. 2012-10 ETHYLENE GLYCOL PRODUCTION FROM COAL-BASED SYNTHESIS GAS by Syed N. Naqvi and R. J. Chang October 2012 Santa Clara, California 95054
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CONTENTS INDUSTRY STATUS... 1 Uses... 1 Demand... 1 Capacity... 1 World Capacity by Region... 1 Production Processes... 2 World Capacity by Production Process... 2 China Capacity by Production Process... 3 China Capacity by Oxalate Ester Process... 4 China Capacity by All Processes... 7 Trade... 9 Prices... 10 TECHNICAL REVIEW... 11 Chemistry... 12 Oxalation... 12 Nitric Oxide Production... 13 Hydrogenation... 13 Patent Review... 14 Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences... 14 PROCESS DESCRIPTION... 24 Section 100 Crude Ethylene Glycol Production... 25 Section 200 Refined Ethylene Glycol Production... 26 PROCESS DISCUSSION... 41 Catalysts... 41 Reactors... 41 Carrier Gas... 42 Product Separation/Recovery... 42 Materials of Construction... 42 Process Design Optimization... 42 COST ESTIMATES... 42 Fixed-Capital Costs... 43 Production Costs... 43 2012 IHS iii PEP Review 2012-10
FIGURES 1 2011 Global EG Capacity Distribution by Region... 1 2 2011 Global EG Capacity Distribution by Technology... 3 3 EG Capacity Distribution by Technology in China... 4 4 China EG Imports by Country or Region... 10 5 EG Prices in China 2006 2011... 11 6 Coal to Ethylene Glycol Overall Process Schematic... 13 7 Continuous Gas-Phase Oxalate Production Process as Disclosed in CN1054765A... 15 8 Nitric Oxide Production as Disclosed in CN1772600A... 21 9 Ethylene Glycol Production from Coal-Based Synthesis Gas Process Flow Diagram... 58 2012 IHS iv PEP Review 2012-10
TABLES 1 EG via Oxalate Ester Projects in China... 5 2 Historical and Projected EG Capacity in China based on Technologies other than Oxalate Ester... 8 3 Historical and Projected EG Capacity by Technology in China... 9 4 Summary of Gas Purification Examples as Disclosed in CN1054765A... 16 5 Summary of Oxalate Production Examples as Disclosed in CN1054765A... 18 6 Summary of Oxalate Production Examples as Disclosed in CN1148589A... 20 7 Summary of Experiments as Disclosed in CN102247851A... 22 8 Summary of Experiments as Disclosed in CN102247847A... 24 9 Ethylene Glycol Production from Coal-Based Synthesis Gas Design Bases... 28 10 Ethylene Glycol Production from Coal-Based Synthesis Gas Stream Flows... 31 11 Ethylene Glycol Production from Coal-Based Syntheis Gas Major Equipment... 38 12 Ethylene Glycol Production from Coal-Based Synthesis Gas Utilities Summary... 45 13 Ethylene Glycol Production from Coal-Based Synthesis Gas Total Capital Investment... 46 14 Ethylene Glycol Production from Coal-Based Synthesis Gas Capital Investment by Section... 47 15 Ethylene Glycol Production from Coal-Based Synthesis Gas Production Costs... 48 16 Ethylene Glycol Production from Coal Utilities Summary... 50 17 Ethylene Glycol Production from Coal Total Capital Investment... 51 18 Ethylene Glycol Production from Coal Capital Investment by Section... 52 19 Ethylene Glycol Production from Coal Production Costs... 53 20 Coal to Monoethylene Glycol Patent Summary... 55 2012 IHS v PEP Review 2012-10