Perspectives for Greening European Fossil-Fuel Infrastructures Through Use of Biomass: The Case of Liquid Biofuels Based on Lignocellulosic Resources

Given the importance of climate change it is vital to find a transition away from fossil fuels. The transition will include electrification of several sectors, for example road transport, but considering the strong dependency on carbon-based fuels and associated infrastructures, it is reasonable to assume that biomass-based hydrocarbon will play a key role to smoothen the transition away from fossil fuels. This study provides an analysis of direct and indirect technological options for liquid biofuels based on lignocellulosic resources in the context of greening European fossil-fuel infrastructures. Direct options are those which result in integration of biogenic feedstock in a fossil-based process and then co-processing in a downstream conventional unit or substituting a conventional part of the production chain of a liquid fuel by a bio-based one. Indirect options are those which pave the way for ramping-up biomass supply chain in the form of infrastructure and market. Examples of direct options in the focus of this study are biomass gasification for production of intermediates and biomass pyrolysis substituting fossil feedstock. Examples of indirect options are co-firing biomass in coal-fired power plants and integrating biomass gasification plants with district heating (DH) networks. Such options are important for establishing biomass supply chains and markets. This study also assesses the potential of biomass use in other industrial sectors not directly related with fossil-based fuel or energy production, such as the pulp and paper industry and the iron and steel industry. In this context, opportunities and barriers for both direct and indirect greening options are discussed, focusing mainly on technological and logistic aspects. It is highlighted that fossil-fuel infrastructures can act as drivers for the development of advanced biofuels production as they can reduce the initial risks, in terms of cost and technological maturity, offering the opportunity to increase gradually the demand for biomass, and develop the logistic infrastructure. It is, however, important to make sure that such biofuel production processes are part of a long-term strategy, which needs incentives to overcome current barriers and eventually phase out fossil infrastructures

Prior Knowledge for Predictive Modeling: The Case of Acute Aquatic Toxicity

Early assessment of the potential impact of chemicals on health and the environment requires toxicological properties of the molecules. Predictive modeling is often used to estimate the property values\ua0in silico\ua0from pre-existing experimental data, which is often scarce and uncertain. One of the ways to advance the predictive modeling procedure might be the use of knowledge existing in the field. Scientific publications contain a vast amount of knowledge. However, the amount of manual work required to process the enormous volumes of information gathered in scientific articles might hinder its utilization. This work explores the opportunity of semiautomated knowledge extraction from scientific papers and investigates a few potential ways of its use for predictive modeling. The knowledge extraction and predictive modeling are applied to the field of acute aquatic toxicity. Acute aquatic toxicity is an important parameter of the safety assessment of chemicals. The extensive amount of diverse information existing in the field makes acute aquatic toxicity an attractive area for investigation of knowledge use for predictive modeling. The work demonstrates that the knowledge collection and classification procedure could be useful in hybrid modeling studies concerning the model and predictor selection, addressing data gaps, and evaluation of models’ performance

Flexibility analysis using boundary functions for considering dependencies in uncertain parameters

In this work, we present a novel approach for considering dependencies (often called correlations) in the uncertain parameters when performing (deterministic) flexibility analysis. Our proposed approach utilizes (linear) boundary functions to approximate the observed or expected distribution of operating points (i.e. uncertainty space), and can easily be integrated in the flexibility index or flexibility test problem. In contrast to the hyperbox uncertainty sets commonly used in deterministic flexibility analysis, uncertainty sets based on boundary functions allow subsets of the hyperbox which limit the flexibility metric but in which no operation is observed or expected, to be excluded. We derive a generic mixed-integer formulation for the flexibility index based on uncertainty sets defined by boundary functions, and suggest an algorithm to identify boundary functions which approximate the uncertainty set with high accuracy. The approach is tested and compared in several examples including an industrial case study

Studying the Role of System Aggregation in Energy Targeting: A Case Study of a Swedish Oil Refinery

The definition of appropriate energy targets for large industrial processes is a difficult task since operability, safety and plant layout aspects represent important limitations to direct process integration. The role of heat exchange limitations in the definition of appropriate energy targets for large process sites was studied in this work. A computational framework was used which allows to estimate the optimal distribution of process stream heat loads in different subsystems and to select and size a site wide utility system. A complex Swedish refinery site is used as a case study. Various system aggregations, representing different patterns of heat exchange limitations between process units and utility configurations were explored to identify trade-offs and bottlenecks for energy saving opportunities. The results show that in spite of the aforementioned limitations direct heat integration still plays a significant role for the refinery energy efficiency. For example, the targeted hot utility demand is reduced by 50-65% by allowing process-to-process heat exchange within process units even when a steam utility system is available for indirect heat recovery. Furthermore, it was found that direct process heat integration is motivated primarily at process unit level, since the heat savings that can be achieved by allowing direct heat recovery between adjacent process units (25-42%) are in the same range as those that can be obtained by combining unit process-to-process integration with site-wide indirect heat recovery via the steam system (27-42%)

The role of biomass gasification in the future flexible power system – BECCS or CCU?

In this work we study if biomass gasification for production of advanced biofuels can also play a role in managing variability in the electricity system. The idea is a CCU/power-to-gas concept to enhance methane production from biomass gasification. The suggested process is flexible in that CO2 not used for methane production can be stored through a BECCS concept that implies negative GHG emissions. For this purpose, rigorous models of three different gasification process configurations were simplified through surrogate modeling and integrated into a dynamic optimization model of regional electricity systems. The results show the diverse advantages of flexible operation between CCU and BECCS and that it is economically beneficial for the system to invest in gasification at the investigated levels of CO2 charge. The gasification option also provides value for low-priced electricity and thus stimulate increased investments in renewable electricity generation, which indicates the importance of considering geographical diversities in the assessment and highlights the importance of studying this type of concept with a time-resolved model. It is clear that the BECCS option is the most used, however, the limited quantities of CO2 used for the CCU option has a large impact on the investments made in the electricity system

Environmental, health and safety assessment of post-combustion CO2 capture processes with phase-change solvents

A class of solvents for chemisorption-based CO2 capture, phase-change solvents, promises significant energy reductions due to liquid-liquid phase separation and partial solvent recycling before CO2 desorption. Although energy consumption is a critical aspect of the CO2 capture process sustainability, a holistic evaluation of health, safety, and environmental impacts is required to confirm the beneficial performance of processes employing phase-change solvents compared to conventional alternatives. This study outlines a method for combining the life cycle and environmental, health and safety hazard assessment. The method is applied for the first time on processes employing two different exemplary phase-change solvents, a reference aqueous solution of methylcyclohexylamine (MCA) and a novel mixture of cyclohexylpropane-1,3-diamine (S1N) and dimethylcyclohexylamine (DMCA). The results show that phase-change solvents have the potential to be a better alternative to conventional amine (i.e., MEA) solvent systems due to the reduced reboiler duty and lower impact on the environment. However, additional care might need to be taken to prevent the potential accumulation of the carcinogenic nitrosamines in the system

Prospective LCA of a biorefinery concept for production of bulk and fine chemicals

The move from a fossil-based to a bio-based economy requires the development of new technologies and process concepts for the production of bio-based energy, chemicals and materials. A biorefinery concept can be designed by integrating such technologies, and can thus provide a viable alternative to produce bulk and fine chemicals. This paper presents a prospective life cycle assessment (LCA) of a novel biorefinery concept, in its early stages of development, for the combined production of adipic acid from forest residues (GROT) and of lutein from micro-algae. Adipic acid is a high-volume chemical (yearly production of approx. 2.3 million tonnes) and is primarily used for the production of nylon-6,6. Conventional adipic acid production from fossil resources is characterized by significant emissions of N2O. Lutein is a high added-value chemical used in the food and pharmaceutical industries, and is conventionally produced from marigold flowers. Furthermore, lignin is an important by-product. The biorefinery concept in this work consists of the pretreatment of GROT, the separation of lignin, and the hydrolysis and fermentation of the pretreated GROT to adipic acid which is then separated and purified. Water, nutrients and CO2 flows from the adipic acid production can be connected to the algae production. Anaerobic digestion is used in this concept to produce biogas from waste streams. Multiple design variants of the biorefinery concept, which is the foreground system, were modelled and simulated based on both experimental and literature data. These variants aimed at narrowing down uncertainties about, for instance, the most suitable GROT pretreatment options, available technologies for anaerobic digestion, and possible routes for further processing of lignin. The data and information resulting from the simulations of the design variants were used to compile the life cycle inventories of each of these variants. The assessment of these variants provides a range for the future environmental performance of the biorefinery concept based on design choices and process conditions. Furthermore, scenarios for future energy systems were considered in order to assess the influence of the background system on the environmental performance of the biorefinery concept. The results provide more relevant information and valuable insight to industry and policy decision makers in order to guarantee an environmentally benign future production of bulk and fine chemicals

Environmental assessment of a biorefinery concept for production of bulk and fine chemicals

Moving from a fossil-based to a bio-based economy requires the development of new technologies and process concepts for the production of bio-based energy, chemicals and materials. Biorefinery concepts can be designed by integrating such technologies in order to provide environmentally and economically attractive alternatives to produce bulk and fine chemicals. This paper presents life cycle and techno-economic assessments of a novel biorefinery concept, in its early stages of development, for the combined production of adipic acid from forest residues and of lutein from micro-algae. Adipic acid is a bulk chemical with a yearly production of approximately 2.3 million tonnes, and is primarily used for the production of nylon-6,6. Conventional adipic acid production from fossil resources causes significant emissions of N2O due to the use of nitric acid as an oxidizing agent. This conventional production can thus lead to a significant climate impact if these emissions are not sufficiently mitigated. Lutein is a high added-value chemical used in the food and pharmaceutical industries, and is conventionally produced from marigold flowers. The biorefinery concept in this work consists of the pretreatment of forest residues, the separation of lignin (which is an important by-product), and the hydrolysis and fermentation of the pretreated forest residues to adipic acid which is then separated and purified. Water, nutrients and CO2 flows from the adipic acid production can be connected to the algae production. The lutein is extracted from the micro-algae using methanol. Anaerobic digestion is used in this concept to produce biogas (another important by-product) from waste streams. The biorefinery concept thus comprises technologies that are at different technology readiness levels (TRLs), from as low as a TRL of 2 for the fermentation process, to a TRL of 9 for the anaerobic digestion process.Twelve design variants of the biorefinery concept were modelled and simulated based on experimental and literature data. These variants aimed at narrowing down uncertainties about, for instance, the performance of the fermentation process. The data and information resulting from the simulations of the design variants were used 1) to compile the life cycle inventories for the LCA of each of these variants, and to do the subsequent life cycle impact assessment, and 2) to determine the capital and operating costs in order to calculate the economic feasibility of the biorefinery design variants. The assessment of all variants provides a range for the environmental and economic performance of the biorefinery concept based on design choices and process conditions. Furthermore, scenarios for future energy systems were considered in order to assess the influence of the background system on the performance of the biorefinery concept.The results show that there is a large variation in the performance among the different design variants, where some designs can significantly improve the prospects for the bio-based adipic acid production. However, the results are strongly dependent on the foreground and background energy systems. The results provide valuable insights to industry and policy decision makers in order to guarantee an environmentally benign and economically feasible production of bulk and fine chemicals in a biorefinery

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

Biofuels as renewable resources are one of the options to meet the challenges of fossil fuel resource depletion and atmospheric pollution. Several studies have focused on the technical, economic, and environmental footprint of biofuels, particularly bioethanol production. However, there has been little effort to incorporate the environmental, health, and safety (EHS) hazards in an inclusive sustainability assessment of bioethanol production alternatives. This study focuses on these sustainability aspects for bioethanol production by employing the EHS and the inherent safety index (ISI) methods. The multicriteria assessment also includes the cumulative energy demand as a widely used lifecycle impact assessment indicator. Sugarcane, corn, and corn stover are considered as biomass resources, and the typical process conditions are used for the base case evaluation. Sensitivity analysis is used to investigate the impact of process conditions, composition of feed, and method settings on the final outcome. The results indicate that both the ISI and the EHS methods present similar overall rankings with sugarcane-derived and corn stover-derived processes as the most and the least hazardous, respectively. However, dissimilarities occur in the evaluation of the process sections, highlighting different hazardous aspects. Finally, including the lifecycle impact assessment in a bicriteria assessment indicates the sugarcane-derived process as clearly superior followed by the corn-derived and the corn stover-derived processe

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

Biofuels as renewable resources are one of the options to meet the challenges of fossil fuel resource depletion and atmospheric pollution. Several studies have focused on the technical, economic, and environmental footprint of biofuels, particularly bioethanol production. However, there has been little effort to incorporate the environmental, health, and safety (EHS) hazards in an inclusive sustainability assessment of bioethanol production alternatives. This study focuses on these sustainability aspects for bioethanol production by employing the EHS and the inherent safety index (ISI) methods. The multicriteria assessment also includes the cumulative energy demand as a widely used lifecycle impact assessment indicator. Sugarcane, corn, and corn stover are considered as biomass resources, and the typical process conditions are used for the base case evaluation. Sensitivity analysis is used to investigate the impact of process conditions, composition of feed, and method settings on the final outcome. The results indicate that both the ISI and the EHS methods present similar overall rankings with sugarcane-derived and corn stover-derived processes as the most and the least hazardous, respectively. However, dissimilarities occur in the evaluation of the process sections, highlighting different hazardous aspects. Finally, including the lifecycle impact assessment in a bicriteria assessment indicates the sugarcane-derived process as clearly superior followed by the corn-derived and the corn stover-derived processe