Employment of Anaerobic Digestion Process of Municipal Solid Waste for Energy

Abstract

Jordan is a country with a population of about five million people. It is considered a developing country that is deficient in generating its own energy source, and it relies significantly on imports of fuels from other countries, which plays an important role in various environmental related problems and issues. Jordan is distinguished among the developing countries by its reasonable industrialization and significant agricultural activities. The amount of waste generated is on the increase due to a continuing significant increase in population and it currently faces pollution of its limited fresh water sources. To mitigate the current and future environmental problems facing Jordan due to fossil fuel use and associated environment problems, Jordan is taking into consideration steps including the utilization of the biogas technology to replace fossil fuel, since Jordan is a nation striving to meet the expected energy demand that grows annually by 6%. Studies of quantity per capita estimates Jordan's generated daily waste as 8,000 tons, which is comparable to that of most semi-industrialized nations. Of that, 3,200 tons is household waste and the rest of it is waste related to industry or agricultural. Much of the total waste is organic, which could be utilized through a process of anaerobic digestion and already has been in use for decades in industrialized nations to produce clean burning methane gas, electricity, fuel, and fertilizers. Anaerobic digestion process releases no greenhouse gases to the atmosphere. Jordan's generated daily waste is estimated around the same as that of most moderately developing nations. Most of the total waste is organic, which could be utilized through a process of anaerobic digestion that does not release greenhouse gases to the atmosphere. Renewable energy and energy conservation, if efficiently utilized, might help to meet the expected increase demand on energy that is growing rapidly. A combined facility (landfill operation and biogas plant) that is established in the capital of Jordan could help reduce the disposal and accumulation of biodegradable solid waste significantly; by 90%. This will help reduce emissions of green house gases (CO₂), reduce the dependency of foreign fossil fuel and would improve issues related to the general environment. This project would be self-supported. This project, if proved to be successful, would be an example that others will follow throughout.     

Biogas: A promising renewable technology and its impact on rural households in Nepal

Nepal, one of the least developed countries, is characterized by very low per capita energy consumption. Because of a lack of other commercial sources of energy, the country relies heavily on traditional fuel source, especially firewood. In order to solve the energy problem in rural areas, the country initiated production and distribution of several renewable energy technologies. Among several technologies, biogas has been proved to be viable and emerged as a promising technology. It has been one of the most successful models for the production of clean, environmental friendly, cost effective source of energy and has multiple benefits. In this paper we present the current state and discuss benefits of the biogas technology in Nepal. Improved health, increased crop productivity, saved time for women are some of the major benefits to the users. It provides economic benefit to the country through reduced deforestation and carbon trading. In addition, by reducing green house gas emission, the technology helps in mitigating global warming and climate change. Thus biogas is a renewable, sustainable and clean source of energy that provides multiple benefits; locally and globally. With some exception, cattle dung has been used primarily as an input and the technology is limited to households only. More systematic and comprehensive study supported by research and development is required to use other degradable waste such as municipal waste to produce biogas on a large scale.     

Design and analysis of a waste gasification energy system with solid oxide fuel cells and absorption chillers

Energy saving is an open point in most European countries where energy policies are oriented to reduce the use of fossil fuels, greenhouses emissions and energy independence, and to increase the use of renewable energies. In the last several years, new technologies have been developed and some of them received subsidies to increase installation and reduce cost. This article presents a new sustainable trigeneration system (power, heat and cool) based on a solid oxide fuel cell (SOFC) system integrated with an absorption chiller for special applications such as hotels, resorts, hospitals, etc. with a focus on plant design and performance. The proposal system is based on the idea of gasifying the municipal waste, producing syngas serving as fuel for the trigeneration system. Such advanced system when improved is thus self-sustainable without dependency on net grid, district heating and district cooling. Other advantage of such waste to energy system is waste management, less disposal to sanitary landfills, saving large municipal fields for other human activity and considerable less environmental impact. Although plant electrical efficiency of such system is not significant but fuel utilization factor along with free fuel, significant less pollutant emissions and self-sustainability are importance points of the proposed system. It is shown that the energy efficiency of such small tri-generation system is more than 83% with net power of 170 kW and district energy of about 250 kW.     

欧美发展氢能和燃料电池汽车的举措及对我国的建议

目前发达国家都在加快对新型车用能源和车辆技术的研发。氢能和燃料电池技术被一些发达国家视为未来道路交通能源的理想解决方案,并投入巨资开展研发活动。目前欧美等国已经形成政府支持下的多方联合开发、推广氢能和燃料电池汽车技术的模式,企业之间也建立起优势互补、强强联合的合作伙伴关系。重点介绍了在欧洲氢能和燃料电池技术领域处于领先地位的德国的主要做法及取得的进展。我国氢能和燃料电池汽车技术的研发、示范和推广工作起步时间不长．国外先进国家的经验和做法值得借鉴。最后为我国发展氢能和燃料电池汽车提出了建议。     

Importance of biomass energy sources for Turkey

Various agricultural residues such as grain dust, crop residues and fruit tree residues are available in Turkey as the sources of biomass energy. Among the biomass energy sources, fuelwood seems to be one of the most interesting because its share of the total energy production of Turkey is high at 21% and the techniques for converting it to useful energy are not necessarily sophisticated. Selection of a particular biomass for energy requirements is influenced by its availability, source and transportation cost, competing uses and prevalent fossil fuel prices. Utilization of biomass is a very attractive energy resource, particularly for developing countries since biomass uses local feedstocks and labor. Like many developing countries, Turkey relies on biomass to provide much of its energy requirement. More efficient use of biomass in producing energy, both electrical and thermal, may allow Turkey to reduce petroleum imports, thus affecting its balance of payments dramatically. Turkey has always been one of the major agricultural countries in the world. The importance of agriculture is increasing due to biomass energy being one of the major resources in Turkey. Biomass waste materials can be used in Turkey to provide centralized, medium- and large-scale production of process heat for electricity production. Turkey's first biomass power project is under development in Adana province, at an installed capacity of 45 MW. Two others, at a total capacity of 30 MW, are at the feasibility study stage in Mersin and Tarsus provinces. Electricity production from biomass has been found to be a promising method in the nearest future in Turkey.     

Political,economic and environmental impacts of biomass-based hydrogen

The purpose of this study is to assess the political, economic and environmental impacts of producing hydrogen from biomass. Hydrogen is a promising renewable fuel for transportation and domestic applications. Hydrogen is a secondary form of energy that has to be manufactured like electricity. The promise of hydrogen as an energy carrier that can provide pollution-free, carbon-free power and fuels for buildings, industry, and transport makes it a potentially critical player in our energy future. Currently, most hydrogen is derived from non-renewable resources by steam reforming in which fossil fuels, primarily natural gas, but could in principle be generated from renewable resources such as biomass by gasification. Hydrogen production from fossil fuels is not renewable and produces at least the same amount of CO₂ as the direct combustion of the fossil fuel. The production of hydrogen from biomass has several advantages compared to that of fossil fuels. The major problem in utilization of hydrogen gas as a fuel is its unavailability in nature and the need for inexpensive production methods. Hydrogen production using steam reforming methane is the most economical method among the current commercial processes. These processes use non-renewable energy sources to produce hydrogen and are not sustainable. It is believed that in the future biomass can become an important sustainable source of hydrogen. Several studies have shown that the cost of producing hydrogen from biomass is strongly dependent on the cost of the feedstock. Biomass, in particular, could be a low-cost option for some countries. Therefore, a cost-effective energy-production process could be achieved in which agricultural wastes and various other biomasses are recycled to produce hydrogen economically. Policy interest in moving towards a hydrogen-based economy is rising, largely because converting hydrogen into useable energy can be more efficient than fossil fuels and has the virtue of only producing water as the by-product of the process. Achieving large-scale changes to develop a sustained hydrogen economy requires a large amount of planning and cooperation at national and international alike levels.     

A review on electricity generation based on biomass residue in Malaysia

Nowadays, biomass is considered as one of the main sources of energy for both developed and developing countries. Malaysia with a large amount of biomass residues as a source of electricity generation is considered as one of the potential countries in this field. This study aims to analyze the potential of recovering energy from major source of biomass residue in Malaysia. For this purpose, the agricultural crop residues and industrial crop waste are investigated. These will contribute substantially to harness a sustainable resource management system in Malaysia to reduce the major disposal problem of biomass residue. The effective use of the waste can supply the required fuel for future electricity generation.     

Syngas from sugarcane pyrolysis: An experimental study for fuel cell applications

The use of biomass for the production of electrical energy is a promising technological solution for those countries where there are problems with the disposal of agricultural waste and/or the production of low-cost energy. The gasification and/or pyrolysis of the biomass produces a gas rich in hydrogen that can be used in a fuel cell system to produce electrical energy with reduced environmental impact and significant energy recovery.In this work, a study of the pyrolysis of Brazilian sugarcane bagasse was carried out. The experimental process consisted of the pyrolysis of the biomass material in a batch pyrolysis reactor. In some runs the biomass was dry, while in others it was pre-treated by the addition of water. It was noted that the water added to the biomass before the pyrolysis process resulted in a decrease in the quantity of steam added to the fuel cell feeding gas, necessary to avoid carbon deposition, and in an increase in cell power, but, at the same time, caused a decrease in the quantity of syngas produced.Then, the composition of the gas obtained from the experimental pyrolysis of the sugarcane was inserted in a simulation tool of a molten carbonate fuel cell system in order to estimate the feasibility of the entire process in terms of operating conditions and electrical performance.The present study indicates that the syngas obtained from the sugarcane biomass (about 40%) can be converted into electricity using a fuel cell system with a high efficiency.     

Technical note Proper utilization of solar energy in Bangladesh: effect on the environment, food supply and the standard of living

The only really sustainable form of energy is solar energy. The densely populated tropical countries can do very well from this completely sustainable energy source without any novel technologies. Most of the commercial energy used world-wide is supplied by using non-renewable resources. Environmental damage—global warming, ozone hole, noise, chemical and radioactive waste—is due to high energy use. Environmental deterioration is a direct consequence of wealth generated and sustained by extremely cheap fossil fuel. The price of fossil fuel does not include the cost for the deterioration of the environment. We show in this paper that even a densely populated country like Bangladesh can attain a high standard of living by a proper utilization of solar energy. We suggest that poor tropical countries should mobilize their resources to develop solar technology.     

Necessity of biodiesel utilization as a source of renewable energy in Malaysia

In recent decades, the energy crisis and environmental issues have become a crucial problem. The rapid industrialization has lead humankind to deplete the fossil fuels and consequently the pollutant emissions have increased in the world. Many investigations have been done to find an alternative fuel to fulfill increasing energy demand. Recently, biodiesel has been introduced as an economical renewable and sustainable fuel which is cited as an environment-friendly resource. Around 350 oil-bearing crops were analyzed and some of them were capable to be considered as potential alternative fuels for diesel engines. These include virgin vegetable oils and waste vegetable oils. Rapeseed, jatropha, soybean, and palm oil are mentioned as the most common sources of biodiesel. Many countries have invested in biodiesel as an acceptable source of energy not only in research area but also in production and export. It has been proven that the biodiesel combustion characteristics are similar as petroleum. Higher ignition pressure and temperature, shorter ignition delay and higher peak release were reported in experimental combustion of biodiesel blends. Also, the efficiency of biodiesel base catalysts is more than enzymes and acid catalysts. This article is a literature review on necessity of biodiesel production as alternative fuel recourse in Malaysia and tries to illustrate the combustion characteristics and pollutant formation in biodiesel application.     

Thermodynamic and exergoeconomic analysis of energy recovery system of biogas from a wastewater treatment plant and use in a Stirling engine

The aim of this research it is to show how the biogas biomethanisation from primary and secondary treatment of activated sludge from a wastewater treatment plant (WWTP), can be an alternative renewable energy option from fossil fuels, which offers competitive advantages and points out new horizons for the use of this fuel. This will allow to achieve some important priorities of energy plans in EU countries: to reduce the organic matter deposited in landfills and CO₂ emissions and to find viable solutions to minimize the environmental impact of sewage sludge (SS).This study analyses the biogas combustion and energy recovery processes from a thermodynamic, thermoeconomic and exergetic point of view.The results show that the boiler of the process is the main source of irreversibility and exergy destruction. Moreover, the energy and exergy economic value of exhaust gases from the combustion chamber, are significant and worthwhile to be exploited. For this reason, the present study explores the applicability and suitability of integrating a Stirling engine in such process. The study reveals that it is possible to create a small micro-cogeneration system which leads to sustainable waste management and energy savings in the treatment plant itself.     

Renewable energy conversion and utilization in ASEAN countries

The world population has passed six billion people and the pressure on basic daily needs is particularly dominant in the developing countries, such as the ASEAN. As most of the natural resources, particularly that of fossil fuel is depleting rapidly, more efficient ways to produce daily necessity are becoming important issues. In addition, both the UNFCCC and the Kyoto Protocol require, that efforts should be directed to improve efficiency of energy conversion devices, effective use of the clean and environmentally friendly renewable source of energy, beside providing sink for the green house gas (GHG) emissions. INFORSE report to the UN Secretary General indicated that the total energy sources in the industrialized countries will diminish drastically, but by providing enough funding for R/D in renewable energy conversion, about 50% of the world energy could be supplied by the developing countries by the year 2050.Despite the above limiting conditions, current data indicated growing energy demand in most of the developing countries, particularly in the ASEAN region. Consequently, these countries, should find out the best strategy in utilizing the available energy sources to maintain sustainable development. One of the reasonable option is to make use of the potential renewable energy resources within the countries and develop industries that complies with the unique characteristics of the energy, which is usually disperse, low density and mostly is still not yet competitive with power generation system using subsidized fuel price. Although some basic R/D on renewable energy technology is also being conducted in ASEAN, more effort, however, is directed to its immediate applications in providing basic energy need for rural house-hold, creating productive uses to process agricultural commodities, and to support general rural electrification programs. Such activity has been supported by relevant and operational government policies, international assistances, and gradual involvement of the private sectors.     

Use of bioethanol for sustainable electrical energy production

Nowadays, the climatic change has addressed the research targets to find renewable energy sources and in order to develop more efficient technologies in a simultaneous way, with the object of promoting a rational use of the energy in the frame of the sustainable development. In this case, an integrated process for sustainable electrical energy production from bioethanol was designed, taking advantage of hydrogen fuel as an energy carrier and fuel cells as efficient and clean devices. The calculated efficiency for this process is better than traditional power cycles, which constitutes a starting point for future developments of this technology.     

Hydrogen recovery,cleaning, compression,storage, dispensing,distribution system and End-Uses on the university campus from combined heat,hydrogen and power system

To address the problem of fossil fuel usage at the Missouri University of Science and Technology campus, using of alternative fuels and renewable energy sources can lower energy consumption and hydrogen use. Biogas, produced by anaerobic digestion of wastewater, organic waste, agricultural waste, industrial waste, and animal by-products is a potential source of renewable energy. In this work, we have discussed the design of combined heat, hydrogen and power (CHHP) system for the campus using local resources. An energy flow and resource availability study is hydrogen recovery, cleaning and energy End-Uses on the university campus from CHHP system. Following the resource assessment study, our team selects Fuel Cell Energy direct fuel cell (DFC) 1500TM unit as a molten carbonate fuel cell. The CHHP system provides the hydrogen for transportation, back-up power and other needs. The research presented in this paper was performed as part of the 2012 Hydrogen Student Design Contest. In conclusion, the CHHP system will be able to reduce fossil fuel usage, greenhouse gas (GHG) emissions and hydrogen generated is used to power different applications on the university campus.     

Analysis of a molten carbonate fuel cell: cogeneration to produce electricity and cold water

The fuel cell is an emerging cogeneration technology that has been applied successfully in Japan, the USA and some countries in the European Union. This system performs direct conversion of the chemical energy of the oxidation of hydrogen from fuel with atmospheric oxygen into direct current electricity and waste heat via an electrochemical process relying on the use of different electrolytes (phosphoric acid, molten carbonate and solid oxide, depending on operating temperature). This technology permits the recovery of waste heat, available from 200°C up to 1000°C depending on the electrolyte technology, which can be used in the production of steam, hot or cold water, or hot or cold air, depending on the associated recuperation equipment. In this paper, an energy, exergy and economic analysis of a fuel cell cogeneration system (FCCS) is presented. The FCCS is applied in a segment of the tertiary sector to show that it is a feasible alternative for rational decentralized energy production under Brazilian conditions. The technoeconomic analysis shows a global efficiency or fuel utilization efficiency of 86%. Analysis shows that the exergy losses in the fuel cell unit and the absorption refrigeration system are significant. Furthermore, the payback period estimated is about 3 and 5 years for investments in fuel cells of 1000 and 1500 US$/kW, respectively.     

A review of performance and emissions of diesel engine operating on dual fuel mode with hydrogen as gaseous fuel

The urge for cleaner and greener sources of energy is rising day by day. Developed countries are already in process of shifting their energy needs from conventional sources to non-conventional/renewable/green sources of energy. These developed countries are also trying to incorporate developing countries to join the battle against global warming and pollution. Examples, of some non-conventional sources of energy are nuclear energy, wind energy etc. One of such cleaner energy source is hydrogen. The high calorific value, availability in abundance and cleaner nature of hydrogen makes it an appropriate substitute for conventional source of energy. An engine using gaseous hydrogen is in the process of being developed. This may revolutionize the battle against pollution and global warming. Use of hydrogen in a diesel engine working on dual-fuel mode has been the interest of many researchers. However utilization of hydrogen fuel changes the ignition delay, combustion duration, peak mean temperature, peak pressure and other combustion parameters change. In the present work, such research works are examined and analyzed in detail. It is also shown, amount of inducted hydrogen dictates many engine parameters such as engine power, torque etc. a separate section is dedicated to study different emissions from the improvised engine. Lastly, it will be clear from the discussion that introduction of gaseous hydrogen to a diesel engine working on dual fuel mode will have optimistic effect on environment.     

Techno‐economic assessment for energy generation using bagasse: case study

Bagasse is selected as the biomass source that is studied because of its annual significant rate production in Iran and potential for energy generation. Bagasse has been as an energy source for the production of energy required to run the sugar factory. The energy needed by factories was supplied by burning bagasse directly inside furnaces, which had an exceptionally low output. To this end, today, a secondary use for this waste product is in combined heat and power plants where its use as a fuel source provides both heat and power. In addition, low efficiency of traditional methods was caused to increase the use of modern methods such as anaerobic digestion, gasification and pyrolysis for the production of bio‐fuels. In this paper, the energy conversion technologies are compared and ranked for the first time in Iran. Therefore, the most fundamental innovation of this research is the choice of the best energy conversion technology for the fuel production with a higher efficiency. To assess the feasibility application and economic benefit of biogas CHP plant, a design for a typical biogas unit is programmed. The results show the acceptable payback period; therefore, economically and technically, biogas CHP plant appears to be an attractive proposition in Iran. Copyright © 2012 John Wiley & Sons, Ltd.     

The political economy of OPEC

We develop a conceptual model that captures OPEC pricing behavior, and apply it to explain the large gap observed between domestic fuel prices in OPEC countries and prices in the rest of the world. We model OPEC as a cartel of nations, not firms, and assume that politicians use two instruments: production quotas and domestic fuel consumption subsidies. The cartel-of-nations model suggests that introduction of alternatives to petroleum products may lead OPEC to reduce exports and increase domestic fuel consumption. The empirical analysis suggests that when OPEC sets production quotas, it places similar weights on consumer and producer surplus. But when OPEC countries set domestic fuel subsidies, on average 6% more weight is given to consumer surplus with some of the OPEC countries pursuing very aggressive domestic cheap fuel policies.     

Carbon black and hydrogen production process analysis

The adoption of new environmentally responsible technologies, as well as, energy efficiency improvements in equipment and processes help to reduce CO2 rate emission into the atmosphere, contributing in delaying the consequences of intensive use of fossil fuels. For more effective actions, it is necessary to make the transition from the fossil-based to the renewable source economy. In this context, hydrogen fuel has a special role as clean vector of energy. Hydrogen has the potential to be decisive in mitigating greenhouse gas emissions, but fossil fuels high profitability due to global energy dependency actually drives the global economy.While renewable energy sources are not worldwide fully established, new technologies should be developed and used for the recovery of energetic streams nowadays wasted, to decarbonize hydrocarbons and to improve systems efficiency creating a path that can help nations and industries in the needed energy economy transition. Hydrogen gas can be generated by various methods from different sources such as coal and water. Currently, almost all of the hydrogen production is for industrial purpose and comes from the Steam Reforming, while the use of hydrogen in fuel cells is only incipient.The article analysis the plasma pyrolysis of hydrocarbons as a decarbonization option to contribute as a step towards hydrogen economy. It presents the Carbon Black and Hydrogen Process (CB&H Process) as an alternative option for hydrogen generation at large scale facility, suitable for supplying large amounts of high-purity carbon in elemental form. CB&H Process refers to a plant with hydrogen thermal plasma reactor able to decompose Hydrocarbons (HC's) into Hydrogen (H2) and Carbon Black (CB), a cleaner technology than its competing processes, capable of generating two products with high added value. Considering the Brazilian context in which more than 80% of the generated electricity comes from renewable sources, the use of electricity as one of the inputs in the process does not compromise the objective of reducing greenhouse gas emissions. It is important to consider that the use of renewable energy to produce two products derived from fossil fuels in a clean way represents integration of technologies into a more efficient system and an arrangement that contributes to the transition from fossil fuels to renewables.The economic viability of the CB&H process as a hydrogen generation unit (centralized) for refining applications also depends on the cost of hydrogen production by competing processes. Steam Methane Reforming (SMR) is a widespread method that produces twice the amount of hydrogen generated by natural gas plasma pyrolysis, but it emits CO2 gas and consumes water, while CB&H process produces solid carbon. For this reason, the paper seeks the carbon production cost by plasma pyrolysis as a breakeven point for large-scale hydrogen generation without water consumption and carbon dioxide emissions.     

Improving inter-plant integration of syngas production technologies by the recycling of CO2 and by-product of the Fischer-Tropsch process

This paper deals with the emission reduction in synthesis-gas production by better integration and increasing the energy efficiency of a high-temperature co-electrolysis unit combined with the Fischer-Tropsch process. The investigated process utilises the by-product of Fischer-Tropsch, as an energy source and carbon dioxide as a feedstock for synthesis gas production. The proposed approach is based on adjusting process streams temperatures with the further synthesis of a new heat exchangers network and optimisation of the utility system. The potential of secondary energy resources was determined using plus/minus principles and simulation of a high-temperature co-electrolysis unit. The proposed technique maximises the economic and environmental benefits of inter-unit integration. Two scenarios were considered for sharing the high-temperature co-electrolysis and the Fischer-Tropsch process. In the first scenario, by-products from the Fischer-Tropsch process were used as fuel for a high-temperature co-electrolysis. Optimisation of secondary energy sources and the synthesis of a new heat exchanger network reduce fuel consumption by 47% and electricity by 11%. An additional environmental benefit is reflected in emission reduction by 25,145 tCO₂/y. The second scenario uses fossil fuel as a primary energy source. The new exchanger network for the high-temperature co-electrolysis was built for different energy sources. The use of natural gas resulted in total annual costs of the heat exchanger network to 1,388,034 USD/y, which is 1%, 14%, 116% less than for coal, fuel oil and LPG, respectively. The use of natural gas as a fuel has the lowest carbon footprint of 7288 tCO₂/y. On the other hand, coal as an energy source has commensurable economic indicators that produce 2 times more CO₂, which can be used as a feedstock for a high-temperature co-electrolysis. This work shows how in-depth preliminary analysis can optimise the use of primary and secondary energy resources during inter-plant integration.