Anaerobic Digestion最新文献

{"title":"Biofuel: An Environmental Friendly Fuel","authors":"A. S. Shote","doi":"10.5772/intechopen.82856","DOIUrl":"https://doi.org/10.5772/intechopen.82856","url":null,"abstract":"Various types of biofuels and feedstocks are considered and discussed in terms of their environmental and economic feasibilities. Biofuel is gaining the centre stage as human activities keep rising and the consequent increase in the discharge of lethal emissions is also a subject of concern. The need to cut down greenhouse gas emissions (i.e. CO2, N2O, CO, NO, SO2) is imperative to preserve our natural biodiversity. Biodiesel and bioethanol are the most common, viable alternatives and infinite green fuels that can be used in internal combustion engine. Biodiesel (commonly from waste cooking oil, nonedible vegetable oil, animal fat and tallow) and bioethanol (usually from forestry waste, Lignocellulosic biomass, starchy and sugary vegetable sources, and agricultural residues) are synthesized from straight vegetable feedstocks to bring their characters close to that of the fossil diesel and gasoline. The candidates as green fuels have the potential to significantly reduce the greenhouse gas emissions by as much as 30% from their combustion in internal combustion engine. The various possible methods used for their productions determine the fuel sensitivity to the environment and the energy balance. In general, the energy balances are positive for both fuel substitutes.","PeriodicalId":379985,"journal":{"name":"Anaerobic Digestion","volume":"48 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128188420","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Biofuel Development in Sub-Saharan Africa","authors":"O. Dahunsi, A. Shoyombo, O. Fagbiele","doi":"10.5772/intechopen.80564","DOIUrl":"https://doi.org/10.5772/intechopen.80564","url":null,"abstract":"The quest for renewable and sustainable energy generation is fast becoming widespread across Africa due to the understanding that there is a need to seek an alternative to fuels of fossil origin, which currently sustains the largest portion of the world’s energy need. Research into the generation of renewable fuels had been on-going in continents like Europe, South America, Asia, and other developed countries bearing in mind the extinction nature of fossil fuels. Globally, attentions are being drawn to fuel generation from biomass and its derivatives such as lignin, triglycerides, cellulose, and hemicelluloses. The aim is to use such fuels for cooking and heating and in vehicles, jet engines, and other applications. Therefore, the integration of the African continent in the race for biofuel production is germane in the quest for survival and developments considering favorable factors like climate, soil, and land mass among other environmental-friendly resources in different African countries.","PeriodicalId":379985,"journal":{"name":"Anaerobic Digestion","volume":"27 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125906327","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Non-Catalytic Reforming of Biogas in Porous Media Combustion","authors":"Mario Toledo Torres","doi":"10.5772/INTECHOPEN.86620","DOIUrl":"https://doi.org/10.5772/INTECHOPEN.86620","url":null,"abstract":"Rich combustion of biogas inside an inert porous media reactor was investigated to evaluate hydrogen and syngas production. Temperature, velocities, and product gas composition of the combustion waves were analysed, while varying its filtration velocity, for a range of equivalence ratios ( φ ) from φ = 1.0 to φ = 3.5. A numerical model based on comprehensive heat transfer and chemical mechanisms was found to be in a good qualitative agreement with experimental data. Partial oxidation products of biogas (H 2 and CO) were dominant on rich combustion. Different gas mixtures of methane and carbon dioxide, which simulated synthetic biogas, and the addition of a varying fraction of water steam were experimentally analysed. It was observed that an increasing steam to carbon ratio (S/C) improved hydrogen and syngas production. The non-catalytic process investigated results in an effective biogas upgrading, and to be essentially higher than under natural gas filtration combustion.","PeriodicalId":379985,"journal":{"name":"Anaerobic Digestion","volume":"56 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-07-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123959398","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Techno-Economic Analysis of Biogas Production from Microalgae through Anaerobic Digestion","authors":"Na Wu, C. Moreira, Yingxiu Zhang, N. Doan, Shunchang Yang, E. Phlips, S. Svoronos, P. Pullammanappallil","doi":"10.5772/INTECHOPEN.86090","DOIUrl":"https://doi.org/10.5772/INTECHOPEN.86090","url":null,"abstract":"Microalgae are a promising feedstock for bioenergy due to higher productivity, flexible growing conditions, and high lipid/polysaccharide content compared to terrestrial biomass. Microalgae can be converted to biogas through anaerobic digestion (AD). AD is a mature technology with a high energy return on energy invested. Microalgae AD can bypass energy intensive dewatering operations that are associated with liquid fuel production from algae. A techno-economic assessment of the commercial feasibility of algae-based biogas production was conducted using Cyanothece BG0011 biomass as an example. BG0011 is a naturally occurring, saline cyanobacterium isolated from Florida Keys. It fixes atmospheric nitrogen and produces exopolysaccharide (EPS). Maximum cell density and EPS concentration of 2.7 and 2.1 g afdw 1 /L (for total algae biomass concentration of 4.8 g afdw/L) were obtained by air sparging. For an areal cell and EPS productivity of 12.4 and 9.6 g afdw/m2/day, respectively, the biomethane production cost was 14.8 $/MMBtu using covered anaerobic lagoon and high-pressure water scrubbing for biogas purification. Electricity production from biogas costs 13 cents/kwh. If areal productivity was increased by 33% from the same system, by sparging air enriched with 1% CO2, then biomethane cost was reduced to 12.16 $/MMBtu and electricity cost to 11 cents/kwh.","PeriodicalId":379985,"journal":{"name":"Anaerobic Digestion","volume":"39 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-04-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125072305","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Microbial Responses to Different Operating Practices for Biogas Production Systems","authors":"M. Westerholm, A. Schnürer","doi":"10.5772/INTECHOPEN.82815","DOIUrl":"https://doi.org/10.5772/INTECHOPEN.82815","url":null,"abstract":"Biogas production requires a number of different microbial groups that work in a synchronized and closely interacting manner. For bioreactors constructed to maximize waste treatment and energy production, it is crucial to manage this process in a way that secures the growth and activity of these microorganisms, as otherwise there is a great risk of process failure. However, the microbiome has a remarkable ability to adapt to various conditions related to substrate composition and operating conditions, thus showing high functional redundancy and robustness. In order to optimize and steer the process, it is important to have an understanding of the anaerobic microbiome, how it responds to various conditions, and its upper limits. This chapter reviews current knowledge regarding microbial responses to different operational management strategies. Microbial responses under various conditions and how the process can be operated to maintain the activity of key species are addressed. Parameters discussed include for example substrate composition, pretreatment, ammonia level, temperature and organic load.","PeriodicalId":379985,"journal":{"name":"Anaerobic Digestion","volume":"14 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-02-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133883794","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Biomass Pretreatment for Enhancement of Biogas Production","authors":"T. Karuppiah, Vimala Ebenezer Azariah","doi":"10.5772/INTECHOPEN.82088","DOIUrl":"https://doi.org/10.5772/INTECHOPEN.82088","url":null,"abstract":"Biomass is a renewable energy source developed from living or recently living plant and animal materials, which can be used as fuel. The main components present in biomass are polymers such as carbohydrate, protein, cellulose, lignin and fat. Biogas is produced when the biomass is anaerobically degraded by microorganisms. The process of anaerobic digestion (AD) takes place in four steps: hydrolysis, acidogenesis, acetogenesis, and methanogenesis. The hydrolysis step is rate limiting due to the presence of complex polymers in biomass. Pretreatment is a process in which the biomass is made ready for microbial attack. This pretreatment can be physical operations such as communition, irradiation etc.; chemical treatment with alkali, acids, wet oxidation etc.; biological pretreatment, by fungi or enzymes; or a combination of these processes. During the pretreatment process, the compact structure of biomass is disrupted and exposed which.","PeriodicalId":379985,"journal":{"name":"Anaerobic Digestion","volume":"27 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-01-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116829616","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Introductory Chapter: An Overview of Biogas","authors":"Rajesh Banu Jeyakumar, R. Y. Kannah","doi":"10.5772/INTECHOPEN.82198","DOIUrl":"https://doi.org/10.5772/INTECHOPEN.82198","url":null,"abstract":"According to the International Energy Agency Report 2018, the global energy demands (GED) elevated 2.1% from the previous year. However, 70% of GED was met through oil, coal and fossil fuel. Among these, fossil fuel accounts for 81% of total energy demand (TED). The percentage of fossil fuel remains unchanged for the past three decades. Exploitation of fossil fuel extended the emission of carbon dioxide (CO2) to 32.5 GT (gigatonnes) in the year 2017. Surplus emission of greenhouse gases (GHG) into the atmosphere is the major contributor for global warming and climate change. On considering, the profile of GHG emission researchers comes out with innovative ideas to minimize the emission. Nowadays, researchers and policymakers are working together to recognize alternative energy source to encounter the energy demand and global warming impacts. Anaerobic digestion (AD) process is the cost-effective and emerging technology to derive biogas from various liquids and solid wastes. AD process is more suitable for valorization of high-strength organic waste under both mesophilic (30–40°C) and thermophilic (50–60°C) conditions. AD process is otherwise termed as biomethanation or biochemical degradation. AD process is a more environmentalfriendly, energy-yielding and more efficient bioenergy production method than other waste processing technologies. AD process dominant by anaerobic microbes, which plays major role in conversion of organic rich waste biomass into two valuable products such as methane and nutrient rich digested/effluent. Anaerobic breakdown of complex organic waste biomass follows four major steps, and these are (i) hydrolysis, (ii) acidogenesis, (iii) acetogenesis and (iv) methanogenesis. Figure 1 represents the pathway of anaerobic degradation of organic waste. Among them, hydrolysis is the rate-limiting and first step of AD process. During hydrolysis, complex organics (C6H10O4) such as protein, carbohydrate and fat are converted into simple digestible amino acids, monosaccharides and fatty acids. Eq. (1) shows that the reaction occurs during hydrolysis phase; enzymes convert the complex organic substrate into simple monomers (C6H12O6) and hydrogen (H2) as shown below:","PeriodicalId":379985,"journal":{"name":"Anaerobic Digestion","volume":"80 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-11-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114874869","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Searching for Metabolic Pathways of Anaerobic Digestion: A Useful List of the Key Enzymes","authors":"A. Sikora, A. Detman, D. Mielecki, A. Chojnacka, M. Błaszczyk","doi":"10.5772/INTECHOPEN.81256","DOIUrl":"https://doi.org/10.5772/INTECHOPEN.81256","url":null,"abstract":"The general scheme of anaerobic digestion is well known. It is a complex process promoted by the interaction of many groups of microorganisms and has four major steps: hydrolysis, acidogenesis, acetogenesis, and methanogenesis. The aim of the study was to prepare a systematized list of the selected enzymes responsible for the key pathways of anaerobic digestion based on the Kyoto Encyclopedia of Genes and Genomes database resource. The list contains (i) key groups of hydrolases involved in the process of degradation of organic matter; (ii) the enzymes catalyzing reactions leading to pyruvate formation; (iii) the enzymes of metabolic pathways of further pyruvate transformations; (iv) the enzymes of glycerol transformations; (v) the enzymes involved in transformation of gaseous or nongaseous products of acidic fermentations resulting from nonsyntrophic nutritional interactions between microbes; (vi) the enzymes of amino acid fermentations; (vii) the enzymes involved in acetogenesis; and (viii) the enzymes of the recognized pathways of methanogenesis. Searching for the presence and activity of the enzymes as well as linking structure and function of microbial communities allows to develop a fundamental understanding of the processes, leading to methane production. In this contribution, the present study is believed to be a piece to the enzymatic road map of anaerobic digestion research.","PeriodicalId":379985,"journal":{"name":"Anaerobic Digestion","volume":"122 1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-11-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128494202","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Review of Mathematical Models for the Anaerobic Digestion Process","authors":"B. Velázquez‐Martí, O. Meneses-Quelal, J. Gaibor‐Chávez, Z. Niño-Ruiz","doi":"10.5772/INTECHOPEN.80815","DOIUrl":"https://doi.org/10.5772/INTECHOPEN.80815","url":null,"abstract":"To describe anaerobic fermentation, many mathematical models have been suggested. A commonly accepted hypothesis in microbial growth is the speed of cellular reproduction, which is proportional to the concentration of cells at that instant. The constant of proportionality between the speed of growth and cell concentration is called cell growth rate, μ . In many occasions, the cell growth rate is considered constant. This leads to conclude that the concentration of cells versus time presents an exponential function. The consideration of this equation provides a good adjustment in the beginning of central phase of the anaerobic fermentation process. However, it moves away from the measurements when there is a limited reproduction due to lack of nutrients and competition between the cells in the environment. This produces a sigmoidal variation in concentration. To find a suitable fit function for all phases of the process, Gompertz proposes a model that considers the cell growth rate as variable. In this chapter, the Gompertz model, kinetic models, transference, and cone models are evaluated. Different adaptations to fit the variables to the obtained values in the experiments have been reviewed.","PeriodicalId":379985,"journal":{"name":"Anaerobic Digestion","volume":"136 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-11-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132653745","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Experimental Study of CO2 Plasticization in Polysulfone Membrane for Biogas Processing","authors":"S. Lock, K. K. Lau, A. Shariff, Y. Yeong, N. Jusoh","doi":"10.5772/INTECHOPEN.80957","DOIUrl":"https://doi.org/10.5772/INTECHOPEN.80957","url":null,"abstract":"Polymeric membranes have emerged for biogas processing to remove CO 2 from CH 4 . Nonetheless, it is also acknowledged that polymeric membranes have the tendency to sorb highly condensable CO 2 , which consequently swells the polymeric matrix, typically at operating condition higher than the plasticization pressure. The swelling increases void spaces for transport of gas penetrants, which results in an increment in permeability of all gas components at the cost of substantial decrease in membrane selectivity. Despite observations of the end results of plasticization, it is found that many transport property studies include only permeability measurements near ambient conditions. Complementary information on the individual contributions of the sorption and diffusion coefficients to the overall performance typically at non-ambient operating conditions is rarely reported. Therefore, in present study, experimental study has been conducted to fabricate polysulfone (PSF) film. Validity of the developed polysulfone membrane has been verified through characterization and validated with gas transport behavior of published results. Subsequently, transport properties of CO 2 though the PSF membrane at varying operating temperatures has been elucidated. The dual mode sorption and partial immobilization models have been employed to quantify the gas transport properties of noncondensable CH 4 and condensable CO 2 through PSF membrane.","PeriodicalId":379985,"journal":{"name":"Anaerobic Digestion","volume":"134 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-11-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127551453","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}