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The aim of this article is to discuss the properties of pyrolysis liquid products and their primary applications. The pyrolysis of biomass is a promising route for the production of solid (charcoal), liquid (tar and other organics), and gaseous products. These products are of interest as they are possible alternate sources of fuels and chemicals. Pyrolysis liquid is referred to in the literature by terms, such as pyrolysis oil, bio-oil, bio-crude oil, bio-fuel oil, wood liquid, wood oil, liquid smoke, wood distillates, pyroligneous tar, and pyroligneous acid. Bio-oil from biomass pyrolysis mainly consisted of aromatic, aliphatic, and naphthenic hydrocarbons and oxygenated compounds, such as phenols, furans, alcohols, acids, ethers, aldehydes, and ketones. Bio-oil has a higher energy density than biomass, can be readily stored and transported, and can be used either as a renewable liquid fuel or chemical production. [ABSTRACT FROM AUTHOR]

The aim of this study is to obtain pyrolysis products (solid, liquid, and gas) from black locust (Robinia pseudoacacia) in the presence of perlite. These include oil, water-soluble products, char, permanent gases, and C1-C4 hydrocarbon gases. The yields of liquid products increase with increasing temperature and perlite. The highest yield of liquid products was 61.9%, which can be obtained from the pyrolysis with 10.0% perlite. The yields of liquid products sharply increase between 3.5 and 6.5min with 2.5% perlite run, whereas 3 and 7min with 10.0% run. Then the yields approach the plateau value after 11 min for all runs. The influence of residence time on the yield of products is small, with a slight decrease in oil yield and increase in char yield. Charcoal yields from 2.5% perlite run were 64.9 and 30.5% for 5 and 20min, respectively. [ABSTRACT FROM AUTHOR]

This article presents a detailed review of thermochemical routes for hydrogen production from biomass as a renewable and alternative energy source. Hydrogen is currently derived from non-renewable natural gas and petroleum, but could, in principle, be generated from renewable resources such as biomass. The production of hydrogen from fossil fuels causes the co-production of CO2, which is assumed to be the main factor responsible for the so-called “greenhouse effect.” The production of hydrogen from biomass has several advantages compared to that of fossil fuels. The methods available for hydrogen production from biomass can be divided into two main categories: thermochemical and biological routes. Hydrogen can be produced from biomass by pyrolysis, gasification, steam gasification, and steam-reforming of bio-oils. [ABSTRACT FROM AUTHOR]

Hydrogen is considered in many countries to be an important alternative energy vector and a bridge to a sustainable energy future. The “hydrogen economy” is being promoted as one of the solutions of the world's energy problems. A hydrogen economy, the long-term goal of many nations, can potentially confer energy security, along with economic and environmental benefits. The Global Hydrogen Vision envisions hydrogen as a flexible, safe, affordable, domestic energy resource to be used in all sectors of the economy and all regions of the world. There are many technical and economic challenges to be overcome before the vision of a hydrogen economy becomes reality. Technical challenges in achieving a hydrogen economy include lowering the cost of hydrogen production, storage, delivery, and end use applications. [ABSTRACT FROM AUTHOR]

This article reviews the applications and performance of microbial fuel cells as an alternative energy option. This technology involves using microorganisms, like bacteria, to oxidize biodegradable substrates as fuels through biological processes to produce electrons, which are then shuttled to an external electron acceptor (anode), and transferred to a cathode via copper wire, thus producing electricity. The performance of a microbial fuel cell can be influenced by several factors. The performance of a microbial fuel cell, as well as other fuel cells, is determined by the current, power density, and rate of fuel oxidation. Various factors can influence the rate of fuel oxidation, including the anodic catalytic activity, fuel diffusion, and the diffusion and consumption of electrons and protons. A microbial fuel cell generates electricity directly from electron donors through the microbial activity. Electricity generation in microbial fuel cells is based on the metabolic activity of living microorganisms. This fact requires that such fuel cell systems have to run under conditions predefined by the optimum growth and living conditions of the utilized microorganisms. Thus, microbial fuel cells are usually operated at ambient temperature, atmospheric pressure, and at pH neutral or only slightly acidic conditions. [ABSTRACT FROM AUTHOR]

This article reviews biological production processes of hydrogen as a renewable and alternative energy source. Biological hydrogen produced from renewable sources (biomass, water, and organic wastes) either biologically or photo-biologically is called “biohydrogen.” The phenomenon of biological hydrogen production was observed one century ago. When the oil crisis broke out in 1970s, the technology started receiving attention, especially in hydrogen production by photosynthetic process. Biological hydrogen production is one of the alternative methods where processes can be operated at ambient temperatures and pressures, and are less energy intensive and more environmentally friendly. Biological production of hydrogen as a by-product of microorganism metabolism is an exciting new area of technology development that offers the potential production of usable hydrogen from a variety of renewable resources. [ABSTRACT FROM AUTHOR]

The aim of this study was to obtain bio-oil from pyrolysis of black alder (Alnus glutinosa). Liquid, solid and gaseous products were obtained from black alder wood pyrolysis. These included oil, water-soluble products, char, permanent gases, and C1-C4 hydrocarbon gases. The yields of bio-oil versus time by pyrolysis of black alder wood samples were very sharply increased from 10 to 25 min from approximately 9.3 to 36.4%, respectively. Then it approached the plateau value after 25 min. The influence of residence time on the yield of products is small, with a slight decrease in oil yield and increase in char yield. The yields of charcoal were 77.2 and 31.4% for 10 and 35 min, respectively. [ABSTRACT FROM AUTHOR]

This article deals with a review of modern wind turbine technology. Wind energy for electricity production today is a mature, competitive, and virtually pollution-free technology widely used in many areas of the world. Wind technology converts the energy available in wind to electricity or mechanical power through the use of wind turbines. A wind turbine is a machine for converting the mechanical energy in wind into electrical energy. Wind turbines capture the power from the wind by means of aerodynamically designed blades and convert it into rotating mechanical power. Wind turbine blades use airfoils to develop mechanical power. Recent advances in technology and performance have resulted in current wind turbine designs being increasingly efficient, cost effective, and reliable. [ABSTRACT FROM AUTHOR]

The aim of this paper is to investigate the global contribution of carbon capture and storage technologies to mitigating climate change. Carbon capture and storage is a technology that comprises the separation of from carbon dioxide industrial- and energy-related sources, transport to a storage location (e.g., saline aquifers and depleted hydrocarbon fields), and long-term isolation from the atmosphere. The carbon dioxides emitted directly at the power stations are reduced by 80 to 90%. In contrast, the life cycle assessment shows substantially lower reductions of greenhouse gases in total (minus 65 to 79%). [ABSTRACT FROM AUTHOR]

The aim of this study is to obtain pyrolysis liquid products from waste engine oil in the presence of wood ash. Petroleum-based waste engine oil can be converted into reusable products such as gasoline and diesel fuel. Possible acceptable processes are distillation, cracking, and pyrolysis. Distillation technique is one of the cheapest and most efficient processes experienced in recycling of waste engine oils. The aims of waste engine oil processing are upgrading via recycling and re-refining processes of the petroleum-based wastes by converting them into reusable products such as gasoline and heavy oil. The pyrolysis liquid products of waste engine oil can be used as alternative engine fuel. The highest yield of liquid product was 84.7%, which can be obtained from the pyrolysis with 15% wood ash run. [ABSTRACT FROM AUTHOR]

The aim of the present article is to investigate biodiesel production via transesterification process and effect of reaction parameters on conversion yield. Biodiesel (fatty acid methyl esters) is a notable alternative to the widely used petroleum-derived diesel fuel since it can be generated by domestic natural sources such as soybeans, rapeseeds, coconuts, and even recycled cooking oil, and thus reduces dependence on diminishing petroleum fuel from foreign sources. The problems with substituting triglycerides for diesel fuels are mostly associated with their high viscosities, low volatilities, and polyunsaturated character. The purpose of the transesterification process is to lower the viscosity of the oil. [ABSTRACT FROM AUTHOR]

As concern about global warming and dependence on fossil fuels grows, the search for renewable energy sources that reduce CO2 emissions becomes a matter of widespread attention. Production of ethanol (bioethanol) from biomass is one way to reduce both the consumption of crude oil and environmental pollution. Using bioethanol-blended fuel for automobiles can significantly reduce petroleum use and exhaust greenhouse gas emission. While more expensive to produce than other fuel types, bioethanol production boosts the farm economy. Up to 80% of production cost is the cost of feedstock. Bioethanol can be produced from cellulose feedstocks such as corn stalks, rice straw, sugar cane bagasse, pulpwood, switchgrass, and municipal solid waste. [ABSTRACT FROM AUTHOR]

This article reviews the production processes and characterization of biogas as an alternative energy source. Biogas, the gas generated from organic digestion under anaerobic conditions by mixed population of microorganisms, is an alternative energy source, which has been commenced to be utilized both in rural and industrial areas at least since 1958. Biogas technology offers a very attractive route to utilize certain categories of biomass for meeting partial energy needs. Unlike other forms of renewable energy, biogas neither has any geographical limitations and required technology for producing energy and it is neither complex or monopolistic. [ABSTRACT FROM AUTHOR]

The aim of this article is to investigate the contribution of biomass energy to global energy demand and energy production from biomass. Biomass energy plays a vital role in meeting local energy demand in many regions of the developing world. Biomass energy utilization has gained particular interest in recent years due to the progressive depletion of conventional fossil fuels, which calls for an increased use of renewable energy sources. Biomass energy is more economical to produce and it provides more energy than other energy forms. Biomass production is eight times greater than the total annual world consumption of all other energy sources. [ABSTRACT FROM AUTHOR]

The aim of this study is to investigate gasification technologies and gasification of biomass for gaseous products. The gasification of biomass is a thermal treatment, which results in a high proportion of gaseous products and small quantities of char (solid product) and ash. At temperatures of approximately 873-1,273 K, solid biomass undergoes thermal decomposition to form gas-phase products that typically include H2, CO, CO2, CH4, H2O, and other gaseous hydrocarbons. Hydrogen gas was produced on a pilot scale by steam gasification of charred cellulosic waste material. The yield from steam gasification increases with increasing water to sample ratio. The yields of hydrogen from the pyrolysis and the steam gasification increase with the increase of temperature. In general, the gasification temperature is higher than that of pyrolysis and the yield of hydrogen from the gasification is higher than that of the pyrolysis. [ABSTRACT FROM AUTHOR]

Hydrogen is a promising renewable fuel for transportation and domestic applications. Hence, in both the near term and long term, hydrogen demand is expected to increase significantly. Producing hydrogen, as well as any other synthetic fuel, will inevitably cost more energy than pumping up oil or using other fossil fuels. In this work, a review is made of the alternative technological methods that could be used to produce this fuel. Hydrogen can be generated in a number of ways, such as electrochemical processes, thermochemical processes, photochemical processes, photocatalytic processes, or photoelectrochemical processes. The thermal production process, which uses steam to produce hydrogen from natural gas or other light hydrocarbons, is most common. Steam reforming of natural gas is currently the least expensive method of producing hydrogen and is used for about half of the world's production of hydrogen. Approximately 95% of the hydrogen produced today comes from carbonaceous raw material, primarily fossil in origin. [ABSTRACT FROM AUTHOR]

Vegetable oils have become more attractive recently because of their environmental benefits and the fact that it is made from renewable resources. Vegetable oils do not contain any sulfur, aromatic hydrocarbons, metals, or crude oil residues. Short-term engine tests indicate good potential for vegetable oil fuels. Long-term endurance tests may show serious problems in injector coking, ring sticking, gum formation, and thickening of the lubricating oil. The high viscosity of vegetable oil reduces fuel atomization and increases fuel spray penetration. The vegetable oils, as alternative engine fuels, are all extremely viscous with viscosities ranging from 10 to 20 times greater than that of petroleum diesel fuel. Modern diesel engines have fuel-injection systems that are sensitive to viscosity changes. A way to avoid these problems is to reduce the viscosity of vegetable oil in order to improve its performance. There are some methods to reduce the viscosity of vegetable oil. The purpose of this work is to investigate potential solutions for solving the problem of vegetable oil viscosity. [ABSTRACT FROM AUTHOR]

Gasification as a thermochemical process is defined and limited to combustion and pyrolysis. The gasification of biomass is a thermal treatment which results in a high proportion of gaseous products and small quantities of char (solid product) and ash. Biomass gasification technologies have historically been based upon partial oxidation or partial combustion principles, resulting in the production of a hot, dirty, low Btu gas that must be directly ducted into boilers or dryers. In addition to limiting applications and often compounding environmental problems, these technologies are an inefficient source of usable energy. The main objective of the present study is to investigate gasification mechanisms of biomass structural constituents. Complete gasification of biomass involves several sequential and parallel reactions. Most of these reactions are endothermic and must be balanced by partial combustion of gas or an external heat source. [ABSTRACT FROM AUTHOR]

The present work is a study on the pyrolysis mechanisms of biomass structural constituents. Biomass resources include wood and wood wastes, agricultural crops and their waste byproducts, municipal solid waste, animal wastes, waste from food processing, and aquatic plants and algae. The major organic components of biomass can be classified as cellulose, hemicelluloses, and lignin. The pyrolysis is thermal degradation of biomass by heat in the absence of oxygen, which results in the production of charcoal (solid), bio-oil (liquid), and fuel gas products. Thermal degradation of cellulose proceeds through two types of reaction: a gradual degradation, decomposition, and charring on heating at lower temperatures; and a rapid volatilization accompanied by the formation of levoglucosan on pyrolysis at higher temperatures. The hemicelluloses reacted more readily than cellulose during heating. Of the hemicelluloses, xylan is the least thermally stable, because pentosans are most susceptible to hydrolysis and dehydration reactions. Dehydration reactions around 473 K are primarily responsible for thermal degradation of lignin. Between 423 K and 573 K, cleavage of α- and β-aryl-alkyl-ether linkages occurs. Around 573 K, aliphatic side chains start splitting off from the aromatic ring. [ABSTRACT FROM AUTHOR]

This article reviews the liquefaction mechanisms of biomass structural constituents. One pivotal study of such liquefaction processes was done in the 1970s funded by the Bureau of Mines of the United States. Liquefaction is a low-temperature, high-pressure thermochemical process using a catalyst. The process produces a marketable liquid product. In the case of liquefaction, macromolecule compounds in biomass are degraded into small molecules with or without catalyst in the aqueous medium or using organic solvent. Thus, obtained small molecules are unstable and reactive and can repolymerize into oily products with a wide range of molecular weight distribution. In the liquefaction process, the micellar-like broken-down fragments produced by hydrolysis are degraded to smaller compounds by dehydration, dehydrogenation, deoxygenation, and decarboxylation. These compounds once produced, rearrange through condensation, cyclization, and polymerization, leading to new compounds. Thermal depolymerization and decomposition of biomass, cellulose, hemicelluloses, and products were formed as well as a solid residue of charcoal. [ABSTRACT FROM AUTHOR]

The main objective in doing the present study is to investigate hydrogen production from biomass via pyrolysis and gasification. Hydrogen is currently derived from nonrenewable natural gas and petroleum but could in principle be generated from renewable resources such as biomass. It can be produced from biomass via two thermochemical processes: (1) gasification followed by reforming of the syngas, and (2) fast pyrolysis followed by reforming of the carbohydrate fraction of the bio-oil. Steam reforming of hydrocarbons, partial oxidation of heavy oil residues, selected steam reforming of aromatic compounds, and gasification of coals and solid wastes to yield a mixture of H2 and CO (syngas), followed by water-gas shift conversion to produce H2 and CO2, are well-established processes. The yields of hydrogen from the pyrolysis and the steam gasification increase with increase of temperature. In general, the gasification temperature is higher than that of pyrolysis and the yield of hydrogen from the gasification is higher than that of the pyrolysis. [ABSTRACT FROM AUTHOR]

This paper reviews the production and characterization of biodiesel fuel from vegetable oils as well as the experimental work carried out via supercritical ethanol transesterification. Biodiesel, which can be used as an alternative diesel fuel, is made from renewable biological sources such as vegetable oil and animal fats. More than 100 years ago, a brilliant inventor named Rudolph Diesel designed the original diesel engine to run on vegetable oil. There are more than 350 oil-bearing crops identified, among which only sunflower, safflower, soybean, cottonseed, rapeseed, and peanut oils are considered as potential alternative fuels for diesel engines. The major problem associated with the use of pure vegetable oils as fuels for diesel engines are caused by high fuel viscosity in compression ignition. Dilution, micro-emulsification, pyrolysis, and transesterification are the four techniques applied to solve the problems encountered with the high fuel viscosity. Dilution of oils with solvents and microemulsions of vegetable oils lowers the viscosity, and some engine performance problems still exist. The purpose of the transesterification process is to lower the viscosity of the oil. The transesterfication of triglycerides by methanol, ethanol, propanol, and butanol has proved to be the most promising process. [ABSTRACT FROM AUTHOR]

During the last two decades, significant advances have been made in the reduction of emissions from coal-fired power generating plants. New technologies include better understanding of the fundamentals of the formation and destruction of criteria pollutants in combustion processes (low nitrogen oxides burners) and improved methods for separating criteria pollutants from stack gases (FGD technology), as well as efficiency improvements in power plants (clean coal technologies). Future demand for more environmentally benign electric power, however, will lead to even more stringent controls of pollutants (sulphur dioxide and nitrogen oxides) and greenhouse gases such as carbon dioxide. [ABSTRACT FROM AUTHOR]

The purpose of this work is to investigate biodiesel production processes from vegetable oils. Biodiesel fuel can be made from new or used vegetable oils and animal fats, which are non-toxic, biodegradable, renewable resources. The vegetable oil fuels were not acceptable because they were more expensive than petroleum fuels. Biodiesel has become more attractive recently because of its environmental benefits. With recent increases in petroleum prices and uncertainties concerning petroleum availability, there is renewed interest in vegetable oil fuels for diesel engines. Dilution of oils with solvents and microemulsions of vegetable oils lowers the viscosity, and some engine performance problems still exist. The purpose of the transesterification process is to lower the viscosity of the oil. Pyrolysis produces more biogasoline than biodiesel fuel. [ABSTRACT FROM AUTHOR]

This article considers the influence of coal energy on environmental pollution. Coal is undoubtedly part of the greenhouse problem. The main emissions from coal combustion are sulfur dioxide (SO2), nitrogen oxides (NOx), particulates, carbon dioxide (CO2), and mercury (Hg). Since 1980, despite a 36% increase in electricity generation and more than a 50% increase in coal use, electric utility SO2 and NOx emissions have declined significantly. Globally, the largest source of anthropogenic greenhouse gas (GHG) emissions is CO2 from the combustion of fossil fuels - around 75% of total GHG emissions covered under the Kyoto Protocol. At the present time, coal is responsible for 30-40% of world CO2 emission from fossil fuels. [ABSTRACT FROM AUTHOR]

The aim of this work is to investigate potential of natural gas (NG) in the Middle East. NG is one of the most widely used forms of energy today. NG uses industrial, residential, electric generation, commercial, and transportation sectors. Proved world NG reserves were estimated at 6,076 trillion cubic feet (Tcf). The largest NG reserves are located in the Middle East. Iran contains an estimated 940 Tcf in proven NG reserves, the world's second largest and surpassed only by those found in Russia. NG consumption in the Middle East rose sharply in the 1990s, from 3.7 Tcf in 1990 to 7.9 Tcf in 2001. [ABSTRACT FROM AUTHOR]

Boron fuel is made up of the element boron. Boron as a chemical fuel will be a promising engine fuel in the future. Cars in which boron fuel simply burns will be true zero emission vehicles. Total world production of boron minerals was approximately 4,270,000 tons in 2000. Turkey has the largest boron sources in the world. It is estimated that about 64% of the known reserves are in Turkey, which has a substantial boron extraction industry. The amount of this resource is about 2.5 million tons and has high tenor and quality. [ABSTRACT FROM AUTHOR]