John A. Posada

Potential of bioethanol as a chemical building block for biorefineries: Preliminary sustainability assessment of 12 bioethanol-based products

The aim of this study is to present and apply a quick screening method and to identify the most promising bioethanol derivatives using an early-stage sustainability assessment method that compares a bioethanol-based conversion route to its respective petrochemical counterpart. The method combines, by means of a multi-criteria approach, quantitative and qualitative proxy indicators describing economic, environmental, health and safety and operational aspects. Of twelve derivatives considered, five were categorized as favorable (diethyl ether, 1,3-butadiene, ethyl acetate, propylene and ethylene), two as promising (acetaldehyde and ethylene oxide) and five as unfavorable derivatives (acetic acid, n-butanol, isobutylene, hydrogen and acetone) for an integrated biorefinery concept.

Microbial community-based polyhydroxyalkanoates (PHAs) production from wastewater: Techno-economic analysis and ex-ante environmental assessment.

This work investigates the potential for polyhydroxybutyrate (PHB) production from wastewater, from a techno-economic and an environmental perspective, examining scale-up opportunities and bottlenecks prior to commercialisation. Conceptual process design, economic, environmental impacts and sensitivity analysis are developed for one fermentation process and three downstream processing routes, based on alkali, surfactant-hypochlorite and solvent treatments. Environmentally and cost-wise, the alkali treatment is the most favourable with production costs of 1.40€/kg PHB, global warming potential of 2.4kgCO2-eq/kg PHB and non-renewable energy use of 106MJ/kg PHB. The solvent-based process yields the highest costs and environmental burdens: 1.95€/kg PHB, 4.30kgCO2-eq/kg PHB and 156MJ/kg PHB. The production of PHB from wastewater is identified as an interesting alternative to pure culture-polyhydroxyalkanoates production from sugars. However, these results are not yet competitive with those for the petrochemical counterparts. Additional performance improvements may be possible, through process integration and optimisation.

Optimization of multi-pathway production chains and multi-criteria decision-making through sustainability evaluation: a biojet fuel production case study

Selection of optimal technologies for novel biobased products and processes is a major challenge in process design, especially when are considered many alternatives available to transform materials into valuable products. Furthermore, such technological alternatives vary in their technical performances and cause different levels of economic and environmental impacts throughout their life cycles. Additionally, selection of optimal production pathways requires a shift from the traditional materials management practices to more sustainable practices. This contribution provides a method for optimizing multi-product network systems from a sustainability perspective by applying the GREENSCOPE framework as a sustainable objective function. A case study is presented in which the four GREENSCOPE target areas (i.e., efficiency, energy, economics, and environment) are evaluated by 21 preselected indicators as part of a multi-objective optimization problem of a biojet fuel production network. The biojet fuel production network evaluated in this study consists of four main elements: (1) feedstocks management, (2) conversion technologies, (3) co-products upgrading, and (4) auxiliary sections for in situ production of raw materials and utilities. For the sustainability objective function, the 21 indicators are analyzed considering multiple perspectives of stakeholders to study their influence on the decision-making process. It is, different sets of weighting factors are assigned to each of the four target areas. Hence, this sustainability evaluation from different stakeholders’ perspectives allows identifying optimal networks, specific target areas with great potential for improvements, and processing steps with great influence in the entire network performance. As a result, diverse optimal network arrangements were obtained according to the multiple stakeholders’ perspectives. This evidences that a win–win situation for all sustainability aspects considered can hardly be reached. Finally, this contribution demonstrated the applicability of the proposed methodology for sustainability evaluation, optimization, and decision-making in the context of a multi-product material facility by developing a multi-objective optimization model.

Comparative early stage assessment of multiproduct biorefinery systems: An application to the isobutanol platform

An early stage assessment method is applied to the production of isobutanol from lignocellulosic biomass, and to three multiproduct portfolios from the conversion of isobutanol: Case 1: production of isobutyl acetate and glycerol tert-butyl ether (GTBE), Case 2: production of isobutyl acetate and ketones, and Case 3: production of isobutyl acetate alkanes. The method screens and compares each route with its equivalent petrochemical counterpart. The method is composed by different indicators involving economic and environmental aspects. Sensitivity analyses were carried out to account for variation in prices, weighting factors and distribution of isobutanol to isobutyl acetate (in multiproduct portfolios). Results show that bio-based isobutanol has advantages over fossil-based isobutanol. In multiproduct systems, case 1 performs better, followed by cases 2 and 3. Screening using economic or environmental aspects show to have a significant effect on the results, where bio-based systems tend to perform better when environmental aspects are included.