The biomass is noticed as an alternative energy source to oil, because its energy volume of production is more than 10 times as much as of fossil resources consumption. However, the biomass is solid of irregular form and has high moisture content, so that it cannot be utilized effectively as an energy resource. Then the direct liquefaction of material wood for the architecture, on the assumption of architecture waste wood that is one of the promising biomass, was carried out. The following results were obtained; 1) It does not need to segregate material wood for the architecture as a raw material for the liquefaction, because it shows similar grinding characteristics regardless of the wood species. 2) First, the thermal decomposition reaction of material wood for the architecture occurs, and WIAI (water-insoluble and acetone-insoluble fraction) forms with the dehydration. Secondary, it thermally decomposes and forms WIAS (water-insoluble but acetone-soluble fraction, liquid oil), hydrolyzes and forms WS (water-soluble fraction, organic acids). The dehydration of WIAS and WS generates water.The decarboxylation of WIAS and WS generates carbon dioxide. 3) The pulverizing of material wood for the architecture and the rising of the liquefaction temperature promote the thermal decomposition reaction, and the liquid oil yield can be improved. 4) The material wood for the architecture shows similar liquefaction characteristics regardless of the wood species.
This paper discusses about saccharification behavior of rice hull by Hot-compressed-water (HCW, -300°C, -10MPa) treatment using a percolation type reactor. By this HCW treatment, rice hulls were converted to water solubles (WS). Its yield was 84.3wt%. At the temperature ranging from 140°C to 200°C, hemicellulose (arabinoxylan) was mainly hydrolyzed to arabinose, xylose and xylooligosaccharides. Above 230°C, cellu-lose was hydrolyzed mainly to glucose, fructose and cellooligosaccharides. Obtained saccharides can be used for various chemicals such as functional food and feedstock for ethanol and lactic acid fermentation.
To clarify the optimum pyrolysis condition of the semi-carbonized fuel and the effect of citric acid addition on the transportation, experiments of the “semi-carbonization” pyrolysis were conducted for cellu-lose, citric acid and their mixtures. The acid additives promoted dehydration of cellulose, and affected the weight yield of char derived from cellulose within the temperature region of the semi-carbonization pyroly-sis. The transportation analysis model of the semi-carbonized fuel was presented to evaluate the optimum weight yield for a given transportation distance. It was found that the acid additives reduced the weight yield at a given pyrolysis temperature and contributed to improving the transportation of the semi-carbon-ized fuel.
From a viewpoint of environmental preservation and resource protection, the recycling of wastes has been promoting. Expectations to new energy resource are growing by decrease of fossil fuel. Biomass is one of new energies with prevent global warming. This study is an attempt to burn pelletized woody biomass (Bio-pellet) made from sawdust and logging residue in order to thermally recycle waste products of forestry and lumbering industry. The devolatilization property of Bio-pellet were observed by the thermogravimerty and differential thermal analysis (TG/DTA) to obtained fundamental data of Bio-pellet pyrolysis. The thermogravimetric analyzer was used to measure weight loss and temperature difference. It observed that the weight of Bio-pellet decreased under three stages with endothermic reaction during pyrolysis, and with exothermic reaction during combustion. The combustion behavior of Bio-pellets was observed in the electric furnace, where the video-recording and measurements of pellet temperature and weight were carried out at sequential steps of the combustion process. The effects of furnace temperature and pellet size were exam-ined in order to elucidate the combustion characteristics of Bio-pellets, such as ignition delay, burning period, char-combustion time and the change of weight decrease and temperature rise. The results indicated that they are influenced at each step of the combustion process such as devolatilization, ignition, visible envelope flame combustion and char combustion.
Glucose and glycine as biomass model compounds were reacted in hot-compressed water between 150 and 350°C. The product distribution as gas, char, oil and aqueous products was examined based on the reaction temperature. The Maillard products, melanoidin, were decomposed over 200°C to produce the char, gas, ammonia and decomposed products in aqueous solution. The char was formed in the low reaction temperature-range from 150 to 200°C, while the oil was formed over 250°C. The overall reaction scheme was proposed as follows.
Oil scum, a by-product from the process of the cooking oil production, has not so far been utilized effectively because of its nature as follows. Oil scum is heavy alkaline and is comprised with neutral oil, soap, moisture and so on. In the present study, oil scum was converted into fuel by methylesterification that is the most popular process of biodiesel production from waste cooking oil. The effects of additions of methanol and water on its conversion are examined. Then it was demonstrated that the methyl ester yield was increased by recycling unreactant. Finally, the possibility of a hexane free process proposed is dis-cussed.
Cellulose decomposition behavior in Hot-Compressed-Water (HCW) was investigated. Rate of glucose production was increased according to HCW temperature, however the yield of glucose was peaked about 50% regardless of the processing temperature. This phenomena was occurred by secondary decomposition of hydrolyzate to low molecular weight compounds such as furfural, 5-hydroxymethylfurfural (HMF) and others as seen in acid hydrolysis. Considering the conversion of lignocellulosic biomass to fermentation resources, it's important to grasp these hydrolysis and secondary decomposition behaviors. So, the reaction kinetics analysis was carried out for the data obtained by HCW treatment of cellulose and relating saccha-rides, then, it is clarified that the rate constant of cellulose decomposition was slightly surpassed that of glucose pyrolysis.
A distributed type small-scale gasification and power generation system using a solid waste is devel-oped. In this system, tar and soot components in the pyrolysis gas produced from a gasifier are reformed into gaseous components by using steam and air or oxygen. The reformed gas is introduced into an internal combustion diesel engine as a fuel gas for power generation. In this research, in order to investigate the optimum gasification conditions for woody biomass, three cases were compared by measuring concentrations of inflammable gases, tar and dust in the pyrolysis and reformed gases together with power generation efficiency. The first was the case when steam was supplied into the reformer, the second was the case when steam was supplied into the gasifier, and the last was the case when oxygen was supplied into the reformer.
Food processing waste, the discharge of which is evaluated at 19 million tons in wet weight per year in Japan, is one of the major bioenergy resources. A biomass balance table, developed by the author and others, enables us to evaluate bioenergy supply potential systematically, but it did not evaluate the food processing and distribution wastes. In this study, the authors modify the biomass balance table in order to identify the energy potential of food processing waste. Using the modified table, the ultimate bioenergy supply poten-tials of the food processing waste and the distribution losses are estimated at 83 PJ/year and 15 PJ/year in Japan in 2000, respectively.
In the hot gas cleaning of producer gas generated from biomass gasification at 1173K, the ability of tar removal was investigated using various carbonaceous materials as a bed additive at the temperatures of 473 to 673K. Activated carbon, charcoal, and charcoal derived from feedstock were employed. The ability of tar removal was evaluated based on the difference in weights of the carbonaceous materials, before and after gasification. Carbonaceous materials had the ability of tar removal at the temperatures of 473 to 673K. It was largely dependent on the type of carbonaceous materials used and gas cleaning temperature. The spe-cific surface area and average pore diameter of activated carbon would influence the ability of tar removal, and the activated carbon with a large specific surface area and a large average pore diameter was the most effective for tar removal at 573 K. In charcoal derived from feedstock, the ability of tar removal was similar to that in inactive ceramic balls.