Ethylene Production from Biomass Feedstock

The chemical cluster studied consumes a large amount of ethylene (polymer grade purity 99.95 mol% (Kochar et al., 1981)) of which 200kt/year is imported and about 500kt/year is produced in a conventional steam cracking plant fed mainly with 

This chapter investigates the heat savings potential that can be achieved by integrating an ethanol production plant based on fermentation of lignocellulosic feedstock and an ethanol dehydration plant producing ethylene with an existing chemical cluster. 

In order to investigate overall energy efficiency improvement opportunities in a systematic manner, process integration is used. Thus, the focus of the study is on a holistic approach of the whole process instead of improving single process steps. 

Acid-catalysed hydrolysis with steam explosion Solid/liquid separation between pretreatment steps (press) 

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An approach to the production of ethylene from biomass that does not involve pyrolysis is ethanol dehydration. The catalytic conversion of syngas to ethanol from low-grade biomass (or fossil) feedstocks, and fermentation ethanol via advanced cellulose hydrolysis and fermentation methods, which make it possible to obtain high yields of ethanol from low-grade biomass feedstocks as well, are both expected to be commercialized in the United States (Chapter 11). Which technology becomes dominant in the market place has... 

Propylene is, next to ethylene, the most important basic chemical to produce not only polypropylene but also other intermediates for example propylene oxide and acrylonitrile. Just like ethylene, propylene can be produced via a hydrocarbon feedstock produced from a biomass [35-37]. Bio-glycerol produced as a byproduct of biodiesel can be dehydrogenated to produce propylene [48]. Bio-based ethylene can be dimerized to produce n-butene, which can then react with remaining ethylene via metathesis to produce propylene [49]. The use of fermentation products of biomass such as 1-butanol [50] enables the formation of n-butene, followed by a subsequent methathesis [49]. Alternatively, hydrothermal carboxylate reforming of fermentation products such as butyric acid or 3-hydroxybutyrate is also proposed as a viable option to propylene [51]. 

Unlike ethanol production from corn, ethanol manufactured from sugarcane may be relatively cost-effective as an ethylene feedstock. Dow Chemical announced a sugarcane-to-polyethylene project in Brazil in 2007 that will play a role in evaluating the process economics in the manufacture of polyethylene from a biomass material. 

Figure 4.3 illustrates different possible conversion routes for the production of ethylene from biomass. One way to produce ethylene from renewable feedstock is catalytic dehydration of bioethanol. In the short term, it is likely that bioethanol dehydration for the production of ethylene will be established in regions with cheap access to bioethanol, for example, Brazil, where ethanol usage is on the same level as usage of fossil-based fuels (on an energy basis) in the transportation sector. In Europe and the United States, this trend is expected to occur after the commercial introduction of lignocellulosic ethanol (Jones et al., 2010). 

An early source of glycols was from hydrogenation of sugars obtained from formaldehyde condensation (18,19). Selectivities to ethylene glycol were low with a number of other glycols and polyols produced. Biomass continues to be evaluated as a feedstock for glycol production (20). 

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