Incorporating Exergy Analysis and Inherent Safety Analysis for Sustainability Assessment of Biofuels

Abstract

In the design of chemical/energy production systems, a major challenge is how to quantify the sustainability of the systems. Concerns on economic return and environmental impacts have been well received by researchers and practitioners. However, the irreversibility of the process has not been taken into consideration yet. Based on the first and second laws of thermodynamics, exergy analysis allows accounting for irreversibility in the process and provides a detailed mechanism for tracking the transformation of energy and chemicals. Sustainability assessment in the societal dimension is mostly a “soft” activity, as the aspects to be considered and the method of evaluation are frequently subjective. How to assess the societal impact of a process in the early design stage remains as a challenging issue. This paper will present a sustainability assessment method incorporating economic, environmental, efficiency, and societal concerns. The efficiency assessment is conducted through exergy analysis, while the societal concerns are measured by an enhanced inherent safety index method. In conjunction with a multicriteria decision-analysis method, this methodology will provide critical guidance to the designers. The efficacy of this methodology will be demonstrated through a case study on biodiesel production processes. The results show that the new heterogeneous catalyst process performs better than the traditional homogeneous process in every dimension.

Safety, health, and environmental assessment of bioethanol production from sugarcane, corn, and corn stover

“…Apart from the method-specific scaling and aggregation schemes of the considered categories, an important feature of the method is that it only comprises a general inventory index; therefore, it is not sensitive to the mass of each specific substance as an additional hazard source to the intrinsic substance properties. This method has already been used in the assessment of biofuel production processes [19].…”

“…Because bioethanol production has been considered as a technology for producing energy or materials sustainably, the safety aspects of the production processes must be clarified and carefully checked before a large-scale implementation. However, the studies about the process safety analysis of bioethanol production are lacking, although similar studies have been conducted for biodiesel [19], and there are some reports on the safety of the transportation and handling of bioethanol [20] and the production of bioderived products from bioethanol [21]. In general, the different kinds of biomass used for bioethanol production require different technologies of pretreatment and fermentation, resulting in diverse process structures and operating conditions, which can directly influence the safety performance.…”

Process sustainability of biodiesel production process from green seed canola oil using homogeneous and heterogeneous acid catalysts

“…1), now a days, many researches include ecological and social indicators along with economic studies during the early process development and design stages [6]. From economic point of view, a process with positive or higher profit, net present value (NPV) and discounted cash flow rate of return (DCFROR), also known as internal rate of return (IRR) are considered to be economically feasible [6]. Ecological impacts are evaluated based on the environmental impacts and energy efficiency of the process (Fig.…”

“…This method provides detailed process safety information with minimal process information at the initial stage of design. An algorithm of sequential process sustainability study has been shown by Li et al [6]. According to the algorithm, economic feasibility is conducted first.…”

Impact of local conditions on bio‐based chemical process design: selection of input feedstock and production scale and scenario

“…Simultaneous consideration of these two issues is necessary during the design and assessment of bio-based processes [3][4][5]. Social issue has also been considered as an important metric in design of a sustainable biorefinery [5][6][7][8]. The environmental viability of biobased processes has been rigorously assessed by considering the life cycle of bio-based products in many studies, e.g., [9][10][11][12].…”