| 1. |
- Shanmugam, Vigneshwaran, et al.
(författare)
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The mechanical testing and performance analysis of polymer-fibre composites prepared through the additive manufacturing
- 2021
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Ingår i: Polymer testing. - : Elsevier. - 0142-9418 .- 1873-2348. ; 93
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Forskningsöversikt (refereegranskat)abstract
- The development of fibre composites in recent years has been remarkably strong, owing to their high performance and durability. Various advancements in fibre composites are emerging because of their increased use in a myriad of applications. One of the popular processing methods is additive manufacturing (AM), however, polymer-fibre composites manufactured through AM have a significantly lower strength compared to the conventional manufacturing processes, for instance, injection moulding. This article is a comprehensive review of the mechanical testing and performance analysis of polymer-fibre composites fabricated through AM, in particular fused deposition modelling (FDM). The review highlights the effect of the various processing parameters, involved in the FDM of polymer-fibre composites, on the observed mechanical properties. In addition, the thermal properties of FDM based fibre composites are also briefly reviewed. Overall, the review article has been structured to provide an impetus for researchers in the concerned engineering domain to gain an insight into the mechanical properties of fibre-reinforced polymeric composites manufactured through AM.
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| 2. |
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| 3. |
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| 4. |
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| 5. |
- Aslanzadeh, Solmaz, et al.
(författare)
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The Effect of Effluent Recirculation in a Semi-Continuous Two-Stage Anaerobic Digestion System
- 2013
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Ingår i: Energies. - : M D P I AG. - 1996-1073. ; 6:6, s. 2966-2981
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Tidskriftsartikel (refereegranskat)abstract
- The effect of recirculation in increasing organic loading rate (OLR) and decreasing hydraulic retention time (HRT) in a semi-continuous two-stage anaerobic digestion system using stirred tank reactor (CSTR) and an upflow anaerobic sludge bed (UASB) was evaluated. Two-parallel processes were in operation for 100 days, one with recirculation (closed system) and the other without recirculation (open system). For this purpose, two structurally different carbohydrate-based substrates were used; starch and cotton. The digestion of starch and cotton in the closed system resulted in production of 91% and 80% of the theoretical methane yield during the first 60 days. In contrast, in the open system the methane yield was decreased to 82% and 56% of the theoretical value, for starch and cotton, respectively. The OLR could successfully be increased to 4 gVS/L/day for cotton and 10 gVS/L/day for starch. It is concluded that the recirculation supports the microorganisms for effective hydrolysis of polyhydrocarbons in CSTR and to preserve the nutrients in the system at higher OLRs, thereby improving the overall performance and stability of the process.
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| 6. |
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| 7. |
- Awasthi, Mukesh Kumar, et al.
(författare)
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Advanced approaches for resource recovery from wastewater and activated sludge: A review
- 2023
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Ingår i: Bioresource Technology. - 0960-8524 .- 1873-2976. ; 384
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Forskningsöversikt (refereegranskat)abstract
- Due to resource scarcity, current industrial systems are switching from waste treatment, such as wastewater treatment and biomass, to resource recovery (RR). Biofuels, manure, pesticides, organic acids, and other bioproducts with a great market value can be produced from wastewater and activated sludge (AS). This will not only help in the transition from a linear economy to a circular economy, but also contribute to sustainable development. However, the cost of recovering resources from wastewater and AS to produce value-added products is quite high as compared to conventional treatment methods. In addition, most antioxidant technologies remain at the laboratory scale that have not yet reached the level at industrial scale. In order to promote the innovation of resource recovery technology, the various methods of treating wastewater and AS to produce biofuels, nutrients and energy are reviewed, including biochemistry, thermochemistry and chemical stabilization. The limitations of wastewater and AS treatment methods are prospected from biochemical characteristics, economic and environmental factors. The biofuels derived from third generation feedstocks, such as wastewater are more sustainable. Microalgal biomass are being used to produce biodiesel, bioethanol, biohydrogen, biogas, biooils, bioplastics, biofertilizers, biochar and biopesticides. New technologies and policies can promote a circular economy based on biological materials.
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| 8. |
- Awasthi, Mukesh Kumar, et al.
(författare)
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Biochemical engineering for elemental sulfur from flue gases through multi-enzymatic based approaches – A review
- 2024
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Ingår i: Science of the Total Environment. - 0048-9697 .- 1879-1026. ; 914
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Forskningsöversikt (refereegranskat)abstract
- Flue gases are the gases which are produced from industries related to chemical manufacturing, petrol refineries, power plants and ore processing plants. Along with other pollutants, sulfur present in the flue gas is detrimental to the environment. Therefore, environmentalists are concerned about its removal and recovery of resources from flue gases due to its activation ability in the atmosphere to transform into toxic substances. This review is aimed at a critical assessment of the techniques developed for resource recovery from flue gases. The manuscript discusses various bioreactors used in resource recovery such as hollow fibre membrane reactor, rotating biological contractor, sequential batch reactor, fluidized bed reactor, entrapped cell bioreactor and hybrid reactors. In conclusion, this manuscript provides a comprehensive analysis of the potential of thermotolerant and thermophilic microbes in sulfur removal. Additionally, it evaluates the efficacy of a multi-enzyme engineered bioreactor in this process. Furthermore, the study introduces a groundbreaking sustainable model for elemental sulfur recovery, offering promising prospects for environmentally-friendly and economically viable sulfur removal techniques in various industrial applications.
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| 9. |
- Bulkan, Gülru, et al.
(författare)
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Techno-Economic Analysis of Bioethanol Plant By-Product Valorization : Exploring Market Opportunities with Protein-Rich Fungal Biomass Production
- 2020
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Ingår i: Fermentation. - : MDPI. - 2311-5637. ; 6:4
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Tidskriftsartikel (refereegranskat)abstract
- The feasibility of dry-grind bioethanol plants is extremely dependent on selling prices of ethanol and by-products, known as Dried distillers grains with solubles (DDGS), and sold as animal feed. Increasing the amount and quality of the by-products can widen potential feed and food markets and improve the process economy and robustness to price fluctuations of ethanol and grain. In this study, the techno-economic analysis of a bioethanol plant was investigated. Integration of edible filamentous fungi into the process leading to the conversion of sidestreams into ethanol and protein-rich fungal biomass for food and feed applications was considered, and its impact was investigated. Sensitivity analysis considered variations on process capacity, on the price of grain and ethanol, and on the price of fungal biomass considering its use for various animal feed (e.g., pig and fish) and human food markets. Selling the fungal biomass in the human food market resulted in 5.56 times higher NPV (net present value) than the base case bioethanol plant after 20 years. Integration of a low-performing strain towards ethanol, followed by the usage of the fungal biomass in the food sector, was found to be the most resistant scenario to the low ethanol selling price and increasing grain price. This study showed that the competitiveness of ethanol plants in the fuel market could be reinforced while meeting the increasing demand for protein sources.
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| 10. |
- Ding, Zheli, et al.
(författare)
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Production of biochar from tropical fruit tree residues and ecofriendly applications – A review
- 2023
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Ingår i: Bioresource Technology. - : Elsevier. - 0960-8524 .- 1873-2976. ; 376
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Forskningsöversikt (refereegranskat)abstract
- Environmental contamination is considered a major issue with the growing urbanization and industrialization. In this context, the scientific society is engaged in searching for a sustainable, safe, and eco-friendly solution. Sustainable materials such as biochar play an important role in environmental contamination. It has some specific properties such as micropores which increase the surface area to bind the pollutants. This review endeavors to analyze the potential of fruit wastes especially tropical fruit tree residues as potential candidates for producing highly efficient biochar materials. The review discusses various aspects of biochar production viz. pyrolysis, torrefaction, hydrothermal carbonization, and gasification. In addition, it discusses biochar use as an adsorbent, wastewater treatment, catalyst, energy storage, carbon sequestration and animal feed. The review put forward a critical discussion about key aspects of applying biochar to the environment.
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| 11. |
- Duan, Yumin, et al.
(författare)
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Sustainable biorefinery approaches towards circular economy for conversion of biowaste to value added materials and future perspectives
- 2022
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Ingår i: Fuel. - : Elsevier BV. - 0016-2361 .- 1873-7153. ; 325, s. 124846-124846
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Tidskriftsartikel (refereegranskat)abstract
- With the huge energy demand inevitably exacerbates the non-renewable resources depletion and ecological-social challenges, renewable energy has become a crucial participant in sustainable strategy. Biorefinery emerged as a sustainable approach and recognized promising transformation platforms for products, to achieve circular bioeconomy which focuses on the biomass efficient and sustainable valorization, promotes resource regeneration and restorative. The emerged biowaste biorefinery has proved as sustainable approach for integrated bioproducts and further applied this technology in industrial, commercial, agricultural and energy sectors. Based on carbon neutral sustainable development, this review comprehensive explained the biowaste as renewable resource generation and resource utilization technologies from the perspective of energy, nutrient and material recovery in the concept of biorefinery. Integrate biorefinery concepts into biowaste management is promise for conversion biowaste into value-added materials and contribute as driving force to cope with resource scarcity, climate changes and huge material demand in circular bioeconomy. In practice, the optimal of biorefinery technologies depends on environmentally friendly, economic and technical feasibility, social and policy acceptance. Additionally, policy interventions are necessary to promote biowaste biorefinery implements for circular bioeconomy and contribute to low-carbon cleaner environment.
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| 12. |
- Li, Yue, et al.
(författare)
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Sustainable Conversion of Biowaste to Energy to Tackle the Emerging Pollutants: A Review
- 2023
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Ingår i: Current Pollution Reports. - : Springer. - 2198-6592.
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Forskningsöversikt (refereegranskat)abstract
- Biowaste is a major source of organic material that can be converted into energy through various processes such as anaerobic digestion, composting, and pyrolysis. However, emerging pollutants, such as pharmaceuticals, pesticides, herbicides, and personal and household products, are a growing concern in wastewater treatment that can be effectively removed by biowaste-to-energy processes. While these contaminants pose significant challenges, the development and implementation of effective monitoring programs and risk assessment tools help to mitigate their impact on human health and the environment. Likewise, monitoring programs, challenges, legislations, and risk assessment tools are essential for understanding and managing the risks associated with emerging pollutants. Biowaste recycling is an important aspect of a biocircular economy perspective as it involves the conversion of organic waste into valuable resources that can be reused sustainably. The review discusses the modern approaches that offer several advantages, including reducing the waste disposal and generating renewable energy while addressing emerging wastewater treatment pollutants. To achieve the goal of a circular economy, modern biotechnological approaches including anaerobic digestion, composting, bioleaching, bioremediation, and microbial fuel cells offer a sustainable and effective way to convert waste into valuable products. These bioproducts alongside energy generation using waste-to-energy technologies can provide economic benefits through revenue generation, reduced waste disposal costs, and improved resource efficiency. To achieve a biocircular economy for biowaste valorization, several stakeholders, including waste collectors, waste management companies, policymakers, and consumers need to be involved. The sustainable conversion of biowaste to energy is an essential and instrumental technology in environmental sustainability.
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| 13. |
- Mukesh Kumar, Awasthi, et al.
(författare)
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A critical review of organic manure biorefinery models toward sustainable circular bioeconomy: Technological challenges, advancements, innovations, and future perspectives
- 2019
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Ingår i: Renewable & sustainable energy reviews. - : Elsevier BV. - 1364-0321 .- 1879-0690. ; , s. 115-131
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Tidskriftsartikel (refereegranskat)abstract
- Total livestock emissions account for up to 14.5% of man-made greenhouse gas emissions. Counteractive measures, such as circular economy concepts and negative emission technologies are necessary to limit global warming below 1.5 °C. Possible treatment options for organic manure include anaerobic digestion, combustion, gasification, hydrothermal liquefaction and composting. The choice of treatment varies depending on the economics, the requirement of a specific product, and sociocultural factors. Commercialization of these treatments needs a blend of appropriate technology, feasible economics, policy support and agreeable socio-cultural conditions. Key findings of this study include the following: 1. Increasing scientific awareness about manure management and treatment; 2. Building a sustainable cooperative model to commercialize technologies; 3. Creating a market for manure recycling products; 4. The role of policy in supporting technologies and consumers; and 5. The codigestion of substrates for better efficacy. Current trends show minimal actions in place as opposed to the high-rate of acceleration that is necessary.
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| 14. |
- Mukesh Kumar, Awasthi, et al.
(författare)
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Myco-biorefinery approaches for food waste valorization : Present status and future prospects
- 2022
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Ingår i: Bioresource Technology. - : Elsevier. - 0960-8524 .- 1873-2976. ; 360
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Tidskriftsartikel (refereegranskat)abstract
- Increases in population and urbanization leads to generation of a large amount of food waste (FW) and its effective waste management is a major concern. But putrescible nature and high moisture content is a major limiting factor for cost effective FW valorization. Bioconversion of FW for the production of value added products is an eco-friendly and economically viable strategy for addressing these issues. Targeting on production of multiple products will solve these issues to greater extent. This article provides an overview of bioconversion of FW to different value added products.
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| 15. |
- Rajendran, Karthik, et al.
(författare)
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A Novel Process Simulation Model (PSM) for Anaerobic Digestion Using Aspen Plus
- 2014
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Ingår i: Bioresource Technology. - : Elsevier BV. - 0960-8524.
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Annan publikation (mjukvara/multimedium) (övrigt vetenskapligt/konstnärligt)abstract
- A novel process simulation model (PSM) was developed for biogas production in anaerobic digesters using AspenPlus®. The PSM is a library model of anaerobic digestion, which predicts the biogas production from any substrate at any given process condition. A total of 46 reactions were used in the model, which include inhibitions, rate-kinetics, pH, ammonia, volume, loading rate, and retention time. The hydrolysis reactions were based on the extent of the reaction, while the acidogenic, acetogenic, and methanogenic reactions were based on the kinetics. The PSM was validated against a variety of lab and industrial data on anaerobic digestion. The P-value after statistical analysis was found to be 0.701, which showed that there was no significant difference between discrete validations and processing conditions. The sensitivity analysis for a ±10% change in composition of substrate and extent of reaction results in 5.285% higher value than the experimental value. The model is available at http://hdl.handle.net/2320/12358 (Rajendran et al., 2013b).
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| 16. |
- Rajendran, Karthik, et al.
(författare)
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Could it be Possible to Convert Waste-Textiles to Biogas? Yes!
- 2012
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- A two-stage process was developed by serial inter-connection between CSTR (Continuously Stirred Tank Reactor) and UASB (Upflow Anaerobic Sludge Bed) to produce high-rate biogas from waste textiles. Most of the textiles contain cellulose, which could be a potential substrate for biogas production. Blue jeans textile (pretreated and untreated) was used as waste textile in this process to investigate biogas production under semi-continuous conditions. Jeans was pretreated using 85% NMMO (N-Methyl-Morpholine-Oxide), an environmental friendly solvent at 120 °C for 3 h. OLR (Organic Loading Rate) was increased in the order of 2, 2.7, and 4 gVS/L/day respectively. Pretreatment had a significant effect on the biogas production. NMMO pretreatment doubled the biogas yield, during an OLR of 2 g VS/L/day compared to untreated jeans. The OLR could successfully be increased to 2.7 g VS/L/day resulted in 91% and 96% theoretical yield for untreated jeans and pretreated jeans respectively. However, further increase in OLR did not increase the methane production. For the complete process, COD (Chemical Oxygen Demand) efficiency was high for untreated jeans with 65.1% followed by treated jeans with 39.5% in the UASB. CSTR possessed the major share of biogas production for both textiles. Considering the fact that, textile is one of the largest consumer products, a proper way of disposal or treatment is necessary. By biogas production, waste textile could also be treated and a value-added product was obtained.
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| 17. |
- Rajendran, Karthik, et al.
(författare)
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Experimental and economical evaluation of a novel biogas digester
- 2013
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Ingår i: Energy Conversion and Management. - : Elsevier Ltd. - 0196-8904 .- 1879-2227. ; 74, s. 183-191
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Tidskriftsartikel (refereegranskat)abstract
- Many developing countries face an energy demand to satisfy the daily needs of the people. Household biogas digesters are among the interesting solutions to meet the energy demands for cooking and lighting, and at the same time taking care of the kitchen wastes. In this study, a novel textile-based biogas digester was developed. The digester was evaluated for biogas production from a synthetic nutrient and an organic fraction of municipal solid waste (OFMSW) as substrates for more than a year. The obtained biogas productivity in both experiments was 570 L/kgVS/day, which indicates that the digester is as efficient in handling of OFMSW as the synthetic nutrients. Based on the obtained biogas production data, the techno-economic evaluation and sensitivity analysis for the process were performed, replacing LPG and kerosene consumption with biogas in households. A 2-m3 digester can supply the fuel needed for cooking for a family of 4–6 people. The sum of investment and 15-years operational costs of this digester was 656 USD, which can be compared with 1455 USD for subsidized-LPG and 975 USD for kerosene, respectively. The results from the sensitivity analysis show that it was a positive investment, unless the price of kerosene goes down to less than 0.18 USD/L.
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| 18. |
- Rajendran, Karthik, et al.
(författare)
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Household biogas digesters : a review
- 2012
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Ingår i: Energies. - : M D P I AG. - 1996-1073. ; 5:8, s. 2911-2942
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Tidskriftsartikel (refereegranskat)abstract
- This review is a summary of different aspects of the design and operation of small-scale, household, biogas digesters. It covers different digester designs and materials used for construction, important operating parameters such as pH, temperature, substrate, and loading rate, applications of the biogas, the government policies concerning the use of household digesters, and the social and environmental effects of the digesters. Biogas is a value-added product of anaerobic digestion of organic compounds. Biogas production depends on different factors including: pH, temperature, substrate, loading rate, hydraulic retention time (HRT), C/N ratio, and mixing. Household digesters are cheap, easy to handle, and reduce the amount of organic household waste. The size of these digesters varies between 1 and 150 m3. The common designs include fixed dome, floating drum, and plug flow type. Biogas and fertilizer obtained at the end of anaerobic digestion could be used for cooking, lighting, and electricity.
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| 19. |
- Rajendran, Karthik
(författare)
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Industrial Bioprocess Developments for Biogas and Ethanol Production
- 2015
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Current biofuels face a noteworthy misfortune on commercialization because of its economiccomparison with low-cost fuel from the oil reserves. To compete with gasoline as a fuel, thebiofuels need to be economically feasible and demonstrated on a large-scale. Biogas and ethanolhave a great potential as commercial biofuels, even though it has difficulties, for example, highcapitalinvestment, absence of demonstrated innovations, and availability of raw materials and soforth. This thesis focuses on different application-driven bioprocess developments for improvingthe techno-economic feasibility of the biogas and ethanol industries.The biogas industry was studied from three different perspectives:1) Modeling approach in which a Process Simulation Model (PSM) model was developed forpredicting the biogas productions, as exploiting new substrates is vital for a biogas industrygrowth. The PSM model was created using Aspen Plus® which includes 46 reactions of differentphases in the Anaerobic Digestion (AD) processes. It also contains certain important processparameters, thermodynamics, rate-kinetics, and inhibitions involved in the AD processes. PSMwas a library model for the AD processes, which was validated against the laboratory andindustrial data. The validation showed that the PSM predicted the biogas production about 5% inexcess, which could ease the biogas industry to predict biogas from new substrates.2) Simulation approach to study the imperative components affecting the profitability of theplant. For this purpose, a local municipality plant was studied under distinct situations. The choiceof upgrading method, capacity, cost of waste and its processing, number of digesters used, etc.were exploited. The results showed that the collection and transportation fee, landfilling fee, andthe reduced operation of a plant were the main considerations in influencing its profitability.Moreover, it was identified that for bigger cities the decentralization strategy could beat theexpense of collection and transportation of waste, and the plant could obtain a 17.8% return oninvestment.3) Rethinking digester technology in which the cost of the digester was significantly lessenedusing a cutting-edge textile, which was principally intended for developing countries. The digestercost played an important role in consuming biogas for different applications. The textile digesterwas tested on a laboratory scale, followed by field tests in different countries including India,Indonesia, and Brazil. Textile digesters cost one-tenth of the conventional digesters, and thepayback was more or less between 1–3 years, when replacing the Liquefied Petroleum Gas (LPG)and kerosene as a cooking fuel for households.When it comes to ethanol, the first generation ethanol production using grains was financiallypossible with a payback of about 13 years. Nonetheless, with the fluctuation of the oil prices, theethanol industries need to look for alternative sources of revenues. Different retrofits wereconsidered, including the effect of thin-stillage/whole-stillage to ethanol and biomass, in additionto the integration of the first and second generation ethanol production. The results revealed that4% additional ethanol could be obtained when the thin-stillage was converted into ethanol andfungal biomass, while the payback was reduced to 11.5 years. The integration of the first andsecond generation ethanol production revealed that it has a positive influence on the overalleconomics of the process with a payback of 10.5 years. This could help the ethanol industries toconsider a revamp for a better environmental, economic, and energy efficient process.
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| 20. |
- Rajendran, Karthik, et al.
(författare)
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Pretreatment of Lignocellulosic Materials
- 2014
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Ingår i: Bioprocessing of Renewable Resources to Commodity Bioproducts. - : Wiley. - 9781118175835 ; , s. 43-76
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Bokkapitel (refereegranskat)
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| 21. |
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| 22. |
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| 23. |
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| 24. |
- Rajendran, Karthik, et al.
(författare)
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Uncertainty over techno-economic potentials of biogas from municipal solid waste (MSW) : A case study on an industrial process
- 2014
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Ingår i: Applied Energy. - : Pergamon. - 0306-2619 .- 1872-9118. ; 125, s. 84-92
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Tidskriftsartikel (refereegranskat)abstract
- In this study, biogas production from the organic fraction of the MSW (OMSW) was simulated in six different scenarios, using Aspen plus® based on industrial data. The economic evaluations were made using the Aspen process economic analyzer, considering the plant size and the upgrading methods. The base case had an annual processing capacity of 55,000 m3 OMSW. The capital costs and the net present value (NPV) after 20 years of operation were 34.6 and 27.2 million USD, respectively. The base case was compared to the modified scenarios, which had different upgrading methods, processing capacities, addition of biogas from wastewater sludge treatment, and variation of the substrate (OMSW) between ±200 USD/ton. The sensitivity analyses were carried out considering the cost of the OMSW imposed on citizens for collection and transportation of wastes and the different sizes of the plant. The result suggests that producing biogas and selling it, as a vehicle fuel from OMSW is a profitable venture in most scenarios. However, there are some uncertainties, including the collection and transportation costs, landfilling fee, and process operation at lower capacities, which affect its profitability.
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