In this work, we perform a comparative techno-economic and environmental analysis for manufacturing ethylene and propylene from naphtha and from shale gas with rich natural gas liquids (NGLs). We first propose two novel process designs for producing ethylene and propylene from NGLs-rich shale gas. These two designs employ steam co-cracking of an ethane–propane mixture and an integration of ethane steam cracking and propane dehydrogenation, respectively. For benchmarking, we also consider a conventional process design in which ethylene and propylene are produced via steam cracking of naphtha. Detailed process models are developed for all the three designs to obtain the mass and energy balances of each unit operation. On this basis, techno-economic analysis and life cycle analysis are conducted for each of the three designs in order to systematically compare the production costs and life cycle environmental impacts of ethylene and propylene manufactured from shale gas and naphtha based on the same conditions. The economic analysis indicates that manufacturing ethylene and propylene from NGLs-rich shale gas is more attractive than from naphtha. The environmental impact analysis shows that manufacturing ethylene and propylene from NGLs-rich shale gas results in lower life cycle water consumption but higher life cycle greenhouse gas emissions.

This paper presents comparative technoeconomic and environmental analyses of three ethylene manufacturing pathways based on ethane-rich shale gas, corn stover, and corn grain. The shalegas-based pathway includes two processing steps, namely, shale gas processing to produce ethane and ethane steam cracking to manufacture ethylene. The two biomass-based pathways also contain two processing steps each, namely, bioethanol production via fermentation and ethylene manufacturing via bioethanol dehydration. A distributed−centralized processing network that consists of distributed ethane/bioethanol production and centralized ethylene manufacturing is employed for each of the three pathways. Detailed process simulation models are developed for major processing steps, and the three pathways are then modeled on five different ethylene production scales. On the basis of the detailed mass and energy balances and life cycle inventory results, we conduct technoeconomic and life cycle analyses to systematically compare the economic and environmental performances of the three ethylene manufacturing pathways. The results indicate that the shale-gasbased pathway is the most attractive due to the lowest break even ethylene prices ($0.32/kg to $1.67/kg); however, it leads to the highest greenhouse gas emissions of about 1.4 kg CO 2 -equiv/kg ethylene. On the contrary, the corn-stover-based pathway results in the lowest greenhouse gas emissions of around −1.0 kg CO 2 -equiv/kg ethylene but the highest break even ethylene prices ($2.0/kg to $4.1/kg). Sensitivity analyses are performed to systematically investigate the influences of parameter deviations on the economic and environmental performances of the three ethylene manufacturing pathways.

This article presents comparative techno-economic and environmental analyses of four representative shale gas monetization options, namely, conventional shale gas processing, large-scale methanol manufacturing, modular methanol manufacturing with shale gas supplied by pipelines, and modular methanol manufacturing with consideration of plant relocation. We first present shale gas supply models for the four gas monetization options. Next, the process designs for shale gas processing and methanol manufacturing from shale gas are described. We develop detailed process simulation models for shale gas processing and methanol manufacturing with different scales using raw shale gas extracted from the Marcellus, Eagle Ford, and Bakken shale plays. On this basis, techno-economic analyses and environmental impact analyses are conducted for the four shale gas monetization options to systematically compare their economic and environmental performances based on the same conditions. The results show that modular methanol manufacturing is more economically competitive than conventional shale gas processing, although it leads to higher environmental impacts. Besides, modular methanol manufacturing is better than large-scale methanol manufacturing for raw shale gas produced from distributed, remote wells from both economic and environmental perspectives. V C 2017 American Institute of Chemical Engineers AIChE J, 64: 495-510, 2018 499 SGP, LMM, and MMM are short for shale gas processing, large-scale methanol manufacturing, and modular methanol manufacturing, respectively. HP is short for high pressure. a Values are based on HHV.

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