N. Mitsumura

Behavior Of Suspended Particulate Matter Emitted From Combustion Of Agricultural Residue Biomass Under Different Temperatures

There are large quantities of waste rice husk and straw estimated around 3.9 million tons as biomass waste every year in Japan. Air pollutants emitted from exhaust gases of rice husk incineration lead to environmental damage, not only because of the influence on global environment and climate, when released into the atmosphere, but also on human health due to local air pollution. Therefore, it is necessary to effectively utilize waste rice husk and straw to reduce air pollutants. In recent years, there has been an increasing demand on the utilization of unused biomass instead of fossil oil fuel in combustors for farminggreenhouses heating during the winter season. The increasing demand will increase the running costs. In general, since these combustors are small in size, there is a lack of regulations or laws (e.g. The Air Pollution Control Act and The Waste Disposal and Public Cleaning Law) in operation for their air pollution control. So far, small size combustors are characterized by their simplicity of structure and low costs. However, they emit visible black carbon (elemental carbon) due to their poor combustion performance. In this study, we investigated that the possibility of the substitution of fossil fuel by waste rice husk and rice straw in laboratory model combustion experiments. We evaluated the emission behavior of harmful air pollutants emitted from rice husk and straw combustion by measuring carbonaceous and ionic composition of suspended particulate matter in the exhaust gases. From the analytical results we found that particulate mass concentrations reduced substantially at high temperature combustion. From the results of our study, it can be suggested that stable combustion performance under suitable conditions

The Behavior Of Suspended Particulate Matter Emitted From The Combustion Of Agricultural Residue Biomass Under Different Temperatures

There are large quantities of waste rice husk and straw estimated around 3.9 million tons as biomass waste every year in Japan. Air pollutants emitted from exhaust gases of rice husk incineration lead to environmental damage, not only because of the influence on global environment and climate, when released into the atmosphere, but also on human health due to local air pollution. Therefore, it is necessary to effectively utilize waste rice husk and straw to reduce air pollutants. In recent years, there has been an increasing demand on the utilization of unused biomass instead of fossil oil fuel in combustors for farminggreenhouses heating during the winter season. The increasing demand will increase the running costs. In general, since these combustors are small in size, there is a lack of regulations or laws (e.g. The Air Pollution Control Act and The Waste Disposal and Public Cleaning Law) in operation for their air pollution control. So far, small size combustors are characterized by their simplicity of structure and low costs. However, they emit visible black carbon (elemental carbon) due to their poor combustion performance. In this study, we investigated that the possibility of the substitution of fossil fuel by waste rice husk and rice straw in laboratory model combustion experiments. We evaluated the emission behavior of harmful air pollutants emitted from rice husk and straw combustion by measuring carbonaceous and ionic composition of suspended particulate matter in the exhaust gases. From the analytical results we found that particulate mass concentrations reduced substantially at high temperature combustion. From the results of our study, it can be suggested that stable combustion performance under suitable conditions Energy and Sustainability IV 315 www.witpress.com, ISSN 1743-3541 (on-line) WIT Transactions on Ecology and The Environment, Vol 176,

Investigation of condensation reaction during phenol liquefaction of waste woody materials

The liquefaction of waste woody materials in the presence of phenol and acid catalyst is a promising method for converting waste woody materials into phenolic resin. The condensation reaction during the liquefaction process is a major problem for its practical application. The effects of various reaction conditions on the extent of the condensation reaction were investigated. The residue content, molecular weight distributions and phenol concentration were measured to investigate the condensation reaction. As a result, it was observed that the intense reaction conditions caused fast liquefaction and led to a remarkable condensation reaction. It was also found that the residue content began to increase at an earlier reaction time when a more remarkable condensation reaction occurred. These results indicated that the condensation reaction was one of the causes for too much degradation of liquefi ed wood molecules under intense liquefaction. The phenol concentrations in the liquefaction products were measured to investigate their effect on the condensation reaction. It was shown that the phenol concentration was 8% lower at the end of the reaction when the condensation reaction was high. It was indicated that the drop in phenol concentration suppressed the liquefaction and promoted the condensation reaction. The addition of methanol during the liquefaction process suppressed the condensation reaction. The residue content was 11% when 50% methanol was added, while it reached 66% when methanol was not added. This can be because methanol reduced the bound phenol, which could be a reaction site of condensation

Suppression method of the condensation reaction during phenol liquefaction of woody material

The liquefaction of woody materials in the presence of phenol and acid catalyst is a promising method to utilize the waste woody materials into phenolic resin. However, the condensation reaction is a major problem for its practical applications. In order to suppress condensation reactions, methanol was added to the liquefaction medium. Even the intense condensation reactions were suppressed by the addition of 50% methanol (mol% to phenol). The effect of methanol was further confirmed by the measurement of molecular weight distribution. In the case of mild condensation, addition of 5% methanol suppressed the production of the residues. At the same time, the liquefaction rates overall were faster than the case without methanol. It was inferred that the existence of methanol lowered the amount of combined phenol which could be the reaction site of the condensation reaction. On the other hand, larger amounts of methanol (100%) retarded the liquefaction rate and the consumption rate of phenol. The actual reaction temperature in the reactor was lower than the setup temperature of the oil bath when the methanol was added. The investigation of the IR spectra showed that there were almost no differences between the functional groups of the liquefied products obtained with and without methanol. The addition of small amounts of methanol could be applicable because the disadvantages of methanol addition could be reduced.

Process analysis of waste bamboo materials using solvent liquefaction

Bamboo is one of the significant biomass resources; it has been used in houses, flooring, construction of scaffolding and bridges, among others. The solvent liquefaction process is one of the promising techniques for effective utilization of waste bamboo materials for the lignocelluloses which can be converted to liquid reactive materials as biomass-based materials. Bamboo has the advantage of providing the liquefied products with a small range of variances. The components of bamboo have high acidity in the presence of mineral acid catalysts and possess the constituents which can react with polyethylene glycol 400 (PEG 400). In this study, waste bamboo materials have been used in liquefaction experiments. The liquefaction process and liquefied residue have been monitored according to the liquefied conditions and surface changes of waste bamboo samples observed by a scanning electron microscope. The changes in the functional groups have been analysed by a Fourier transform infrared spectrometer and behavior of the crystalline structures of liquefied bamboo has been determined by X-ray diffraction. Other experiments, such as degree of polymerization have also been carried out for confirming the results. Regarding the results, it was found that an increment of the temperature and the amount of the acid catalysts improved the efficiency of liquefaction. At the same time, the dissolution time of lignin was significantly shorter than the one of cellulose in the solvent liquefaction process of PEG 400.

Basic study on combustion characteristics of waste rice husk and emission behavior from a new-type air vortex current combustor

There are large quantities of rice husk estimated around 3 million tons as agricultural waste every year in Japan. Air pollutants emitted from exhaust gases of rice husk incineration lead to very important environmental damage, not only because of the influence on global environment and climate, when released into the atmosphere, but also on human health due to the local air pollution. Therefore, it is necessary to effectively utilize the rice husk waste and to reduce the air pollution. We try to develop a new-type air vortex current small-scale combustor which can effectively combust rice husk as biomass energy instead of fossil oil fuel for farming-greenhouses heating during the winter season. In this study, we investigated if rice husk can be fed on the new-type air vortex current small-scale combustor and reduced fossil fuel. The new-type small-scale combustor is able to keep a constant high temperature (about 1000°C) even if the rice husk combustion is not under the best conditions. At the same time, it is also important to evaluate the emission behavior of harmful air pollutants emitted from the rice husk combustion with measuring carbonaceous and ionic composition of suspended particulate matter (SPM) in the exhaust gases from the new-type air vortex current combustor, and to reduce the pollutant emission by controlling the combustion conditions. From the analytical results of the size distribution of carbonaceous composition collected by an air sampler, it is shown that elemental carbon dominated in the coarse

Characterization of liquefied products from model woody components in the presence of mineral acid catalysts

Cellulose and lignin are the main structural polymers in the plant cell wall. Cellulose is the structural component of the primary cell wall of green plants, many forms of algae and the oomycetes. About 40–50% of woody matter is cellulose. Lignin is a highly cross-linked polymer created by the polymerization of substituted phenolic compounds, known as monolignols, such as coniferyl, pcoumaryl, and synapyl alcohol. Liquefaction process is one of the promising techniques for effective utilization of woody biomass for the lignocelluloses can be converted to liquid reactive materials as the bio-based materials. Cellulose would have an advantage of providing liquefied product with small range of variance. The phenolated woody components have high acidity in the presence of mineral acid catalysts and possess the constituents which can react with formaldehyde. In addition, lignin, one of the major woody components including the hydroxyl-benzyl structure, has the potential to react with formaldehyde. However, as its complexity in structure, the liquefaction mechanism and the liquefied products with phenol should be found out to solve some problems such as the reaction efficiency and low molecular weight products, and it will be useful to preparation of bio-based materials thought the liquefaction processes. In our study, two model woody components have been used under the different liquefaction conditions with phenol. In our experiments, the model cellulose component is specially used in the experiment to test the characteristics of the

The Heterogeneous Reaction Between Tar And Ash From Waste Biomass Pyrolysis And Gasification

Fossil energy resources that are available in the world are exhaustible. Therefore, the renewable biomass resource has attracted a lot of attention as the future energy resource. In addition, it is an advantage that the biomass grows while absorbing CO2, contributing to the prevention of global warming. Biomass utilization technologies are classified as pyrolysis and gasification, fermentation, and combustion. Fuel gases and synthesis gases produced by the pyrolysis and gasification is used as power generation, heating, chemical products, etc. However, pyrolysis and gasification processes also generated condensable organic compounds, so-called “tar”. Most tar contents are present as the gases at high temperature. However, when the temperature is cooled down lower than their boiling point, causing a black oily liquid lead to the equipment failure, the appropriate processing is required. As the processing method, using the catalytic tar decomposition has been widely studied. In the present study, we have carried out the thermal decomposition of cellulose, in the experimental apparatus modeling a fluidized bed gasifier. The thermal decomposition of cellulose, tar and gas is generated, tar is collected and cooled, and the gases were measured by a gas-chromatograph with a flame ionization detector (GC-FID) and with a thermal conductivity detector (GCTCD). Then, K and Ca are selected as the catalysts of alkali metals and alkaline earth metals contained in the waste biomass. They are present in the state of oxide or carbonate during pyrolysis and gasification. We conducted a similar experiment. The amount of condensable products and heavy tar were decreased by installing K2CO3 and Ca(OH)2. Additionally, they brought further gas

Process Analysis Of Waste Bamboo Materials Using Solvent Liquefaction

Bamboo is one of the significant biomass resources; it has been used in houses, flooring, construction of scaffolding and bridges, among others. The solvent liquefaction process is one of the promising techniques for effective utilization of waste bamboo materials for the lignocelluloses which can be converted to liquid reactive materials as biomass-based materials. Bamboo has the advantage of providing the liquefied products with a small range of variances. The components of bamboo have high acidity in the presence of mineral acid catalysts and possess the constituents which can react with polyethylene glycol 400 (PEG 400). In this study, waste bamboo materials have been used in liquefaction experiments. The liquefaction process and liquefied residue have been monitored according to the liquefied conditions and surface changes of waste bamboo samples observed by a scanning electron microscope. The changes in the functional groups have been analysed by a Fourier transform infrared spectrometer and behavior of the crystalline structures of liquefied bamboo has been determined by X-ray diffraction. Other experiments, such as degree of polymerization have also been carried out for confirming the results. Regarding the results, it was found that an increment of the temperature and the amount of the acid catalysts improved the efficiency of liquefaction. At the same time, the dissolution time of lignin was significantly shorter than the one of cellulose in the solvent liquefaction process of PEG 400.

Clarification of the reaction at the solution interface of pyrite during oil agglomeration for developing desulfurization and coal cleaning efficiency

Recently, large amounts of waste fine coals have been produced which are difficult to treat because of the high ash content and inorganic sulfuric compounds. In order to make efficient use of waste fine coal, the retrieval technique is necessary for recovery of coal combustible content from fine waste coals. Nowadays a floatation process is able to operate, but it is impractical for developing countries due to high costs. An oil agglomeration process can deal with these problems. In this study, we investigate the mechanism of the solution interface reaction on oil agglomeration in order to separate pyrite sulfur effectively from waste fine coal. For this purpose, we adjusted the pH of the solution of oil agglomeration experiments to the basic condition, which changed the surface characteristics to hydrophilicity from hydrophobicity. Furthermore, pH and dissolved oxygen changes of the solution were continually monitored and free ferric ions of the waste liquid were measured by flame atomic absorption spectrometry. These factors have a relationship with the oxidation and surface reaction of pyrite sulfur in the solution. Under high basic conditions, pyrite sulfur reduction indicated high values since the pyrite surface became hydrophilic due to covering of the surface of the pyrite sulfur by ferric hydroxide. As a result, the pyrite content did not recover together with hydrophobic carbonaceous content especially under high basic conditions.