Advances and emerging techniques for energy recovery during absorptive CO2 capture: a review of process and non-process integration-based strategies

Absorptive CO2 Capture (ACC) is widely embraced as a mature technology to mitigate CO2 emission, but it is energy-intensive and expensive to implement on a commercial scale. It is envisaged that energy recovery could be achieved during ACC by synthesizing and integrating a complex network of flexible heat exchangers to transfer as much energy as possible from a set of hot flows to cold flows. This review provides information on the progress made in the development of process and non-process integration-based techniques alongside their benefits for effective energy recovery during ACC. An exposition on the integration of flexible Heat Exchanger Networks (HENs), its synthesis methodologies, and developments for improving energy recovery during ACC is presented. Furthermore, this review highlights the current state of knowledge creation in process integration and ACC, as well as its underpinning principles, challenges, and opportunities to provide a summary and important discussion on current practices in process integration-based strategies for energy recovery. Current opinions on the integration of flexible HENs for energy recovery during ACC are highlighted. The review also presents a proposed roadmap for large-scale energy recovery during ACC, and suggestions on the improvement opportunities for future research and development were provided. Finally, this review revealed that the integration of flexible HENs is a promising technique for energy recovery during ACC. This study will be beneficial to researchers exploring cost-effective methods for designing sustainable energy systems for effective energy recovery.http://www.elsevier.com/locate/rserpm2022Chemical Engineerin

Update on current approaches, challenges, and prospects of modeling and simulation in renewable and sustainable energy systems

Modeling and simulation (M&S) is a well-known scientific tool that could be used to analyze a system or predict its behavior before physical construction. Despite being an established methodical tool in engineering, only a few review articles discussing emerging topics in M&S are available in open literature, especially for renewable and sustainable energy systems. This review critically examines recent advances in modeling and simulation in the energy sector, with few insights on its approaches, challenges, and prospects in selected renewable and sustainable energy systems (RSES). In addition, the concept of model validation in RSES is systematically discussed based on in-sample and out-of-sample approaches, while potential data sources with crucial elements for model validation in RSES are highlighted. Furthermore, three major groups of sustainable energy system models that play important roles in supporting national and international energy policies arepresented, to bring to light how the modeling of energy systems is evolving to meet its challenges in the design, operation, and control of RSES. This review also presents a comprehensive assessment of the current approaches, challenges, and prospects in modeling the behavior and evaluating the performance of RSES. Finally, areas that need further research and development in renewable and sustainable energy system modeling are also highlighted.https://www.elsevier.com/locate/rserpm2022Chemical Engineerin

Statistical modelling and optimization of alkaline peroxide oxidation pretreatment process on rice husk cellulosic biomass to enhance enzymatic convertibility and fermentation to ethanol

The complex and ordered arrangements of the lignocellulosic materials make them recalcitrant for their conversions to ethanol. Pretreatment is a crucial step in overcoming these hindrances. In this study, a 23 -full factorial design of experiments optimization technique was applied on the alkaline peroxide oxidation pretreatments of rice husks biomass. The low–high levels of the influencing variables on pretreatments were; temperature (100–120 C), time (1–2 h), % (v/v)H2O2 concentration (1–3%). Under the prevailing pretreatments, the optimum conditions were predicted and validated to be 109 C, 2 h, and 1.38% H2O2 which yielded 56% (w/w) cellulose content, 55% (w/w) hemicellulose solubilization, and 48% (w/w) lignin removal. At the established optimum pretreatment conditions, and considering variations in biomass and enzymes loadings, maximum reducing sugars production was 205 mg/g dry biomass at different enzymatic hydrolysis conditions of 3% biomass loading, hydrolysis temperature of 45 C, hydrolysis time of 24 h, and 35 FPU/g cellulose enzyme loading. The highest cellulose conversion of 33% yielded 24 g/L ethanol at the end of the first day of saccharification and fermentation. Physical, structural, and morphological investigations on raw and treated materials using tools such as stereomicroscopy, scanning electron microscopy, and fourier transform infrared spectroscopy further revealed the effectiveness of chosen method on rice husks biomas

Biological and Non-Biological Methods for Lignocellulosic Biomass Deconstruction

Owing to their abundance and cost-effectiveness, lignocellulosic materials have attracted increasing attention in clean energy technologies over the last decade. However, the complex polymer structure in these residues makes it difficult to extract the fermentable sugars. Therefore, various pretreatment regimes have been used resulting in the breaking of lignocelluloses’ physical and chemical structures, thereby enhancing the availability of the polysaccharides which are subsequently hydrolysed into different biocommodities. This chapter provides an evaluation of some of the latest exploited methodologies that are used in the pretreatment of lignocellulosic materials. Moreover, the chapter discusses the advantages and disadvantages of each method

Statistical modelling and optimization of alkaline peroxide oxidation pretreatment process on rice husk cellulosic biomass to enhance enzymatic convertibility and fermentation to ethanol

The complex and ordered arrangements of the lignocellulosic materials make them recalcitrant for their conversions to ethanol. Pretreatment is a crucial step in overcoming these hindrances. In this study, a 23‐full factorial design of experiments optimization technique was applied on the alkaline peroxide oxidation pretreatments of rice husks biomass. The low–high levels of the influencing variables on pretreatments were; temperature (100–120 °C), time (1–2 h), % (v/v)H2O2 concentration (1–3%). Under the prevailing pretreatments, the optimum conditions were predicted and validated to be 109 °C, 2 h, and 1.38% H2O2 which yielded 56% (w/w) cellulose content, 55% (w/w) hemicellulose solubilization, and 48% (w/w) lignin removal. At the established optimum pretreatment conditions, and considering variations in biomass and enzymes loadings, maximum reducing sugars production was 205 mg/g dry biomass at different enzymatic hydrolysis conditions of 3% biomass loading, hydrolysis temperature of 45 °C, hydrolysis time of 24 h, and 35 FPU/g cellulose enzyme loading. The highest cellulose conversion of 33% yielded 24 g/L ethanol at the end of the first day of saccharification and fermentation. Physical, structural, and morphological investigations on raw and treated materials using tools such as stereomicroscopy, scanning electron microscopy, and fourier transform infrared spectroscopy further revealed the effectiveness of chosen method on rice husks biomass

Revising the dark fermentative H2 research and development scenario – An overview of the recent advances and emerging technological approaches

The indiscriminate use of fossil fuels has led to several challenges such as greenhouse gas emissions, environmental degradation, and energy security. Establishment of clean fuels is at the forefront of science and innovation in today’s society to curb these problems. Dark fermentation (DF) is widely regarded as the most promising clean energy technology of the 21st century due to its desirable properties such as high energy content, its non-polluting features, its ability to use a broad spectrum of feedstocks and inoculum sources, as well as its ability to use mild fermentation conditions. In developing nations, this technology could be instrumental in establishing effective waste disposal systems while boosting the production of clean fuels. However, DF is still hindered by the low yields which stagnate its commercialization. This paper reviews the recent and emerging technologies that are gaining prominence in DF based on information that has been gathered from recent scientific publications. Herein, novel enhancement methods such as cell immobilization, nanotechnology, mathematical optimization tools, and technologies for biogas upgrading using renewable H2 are comprehensively discussed. Furthermore, a section which discusses the potential of bioenergy in Sub-Saharan Africa including South Africa is included. Finally, scientific areas that need further research and development in DF process are also presented

The Potential of CO2 Capture and Storage Technology in South Africa’s Coal-Fired Thermal Power Plants

The global atmospheric concentration of anthropogenic gases, such as carbon dioxide, has increased substantially over the past few decades due to the high level of industrialization and urbanization that is occurring in developing countries, like South Africa. This has escalated the challenges of global warming. In South Africa, carbon capture and storage (CCS) from coal-fired power plants is attracting increasing attention as an alternative approach towards the mitigation of carbon dioxide emission. Therefore, innovative strategies and process optimization of CCS systems is essential in order to improve the process efficiency of this technology in South Africa. This review assesses the potential of CCS as an alternative approach to reducing the amount CO2 emitted from the South African coal-fired power plants. It examines the various CCS processes that could be used for capturing the emitted CO2. Finally, it proposes the use of new adsorbents that could be incorporated towards the improvement of CCS technology

Batch Fermentative Biohydrogen Production Process Using Immobilized Anaerobic Sludge from Organic Solid Waste

This study examined the potential of organic solid waste for biohydrogen production using immobilized anaerobic sludge. Biohydrogen was produced under batch mode at process conditions of 7.9, 30.3 °C and 90 h for pH, temperature and fermentation time, respectively. A maximum biohydrogen fraction of 48.67%, which corresponded to a biohydrogen yield of 215.39 mL H2/g Total Volatile Solids (TVS), was achieved. Therefore, the utilization of immobilized cells could pave the way for a large-scale biohydrogen production process

A review on heat and mass integration techniques for energy and material minimization during CO2 capture

Abstract One major challenge confronting absorptive CO2 capture is its high energy requirement, especially during stripping and sorbent regeneration. To proffer solution to this challenge, heat and mass integration which has been identified as a propitious method to minimize energy and material consumption in many industrial applications has been proposed for application during CO2 capture. However, only a few review articles on this important field are available in open literature especially for carbon capture, storage and utilization studies. In this article, a review of recent progress on heat and mass integration for energy and material minimization during CO2 capture which brings to light what has been accomplished till date and the future outlook from an industrial point of view is presented. The review elucidates the potential of heat and mass exchanger networks for energy and resource minimization in CO2 capture tasks. Furthermore, recent developments in research on the use of heat and mass exchanger networks for energy and material minimization are highlighted. Finally, a critical assessment of the current status of research in this area is presented and future research topics are suggested. Information provided in this review could be beneficial to researchers and stakeholders working in the field of energy exploration and exploitation, environmental engineering and resource utilization processes as well as those doing a process synthesis-inclined research