The gasification gas produced in gasification furnace and the bio-mass gas collected from sewerage processing are receiving attention as renewable energy. The bio-mass gas of which the release calorific value is about a tenth of methane calorific value is the gas that contains much inert gas (N2, CO2). It is important that the bio-mass gas is utilized as one of renewable fuel. In this study the profiles of temperature and Carbon mono oxide (CO) concentration in the flame are measured. The blow off velocity is investigated with increasing the fuel velocity. We research into combustion characteristic and stability limits of the diffusion flame for utilities of biomass-gas.
A new type of circulating fluidized bed gasifier, called“fluidized bed gasifier with triple-beds and dual circulation”, was proposed. The objectives of this work are to clarify the gasification characteristics of woody biomass by using porous alumina as bed material in a laboratory-scale hot model gasifier. The tested biomass is wood pellet. As a result, the amount of H2 formed was increased due to the partial cracking in pyrolysis. The amount of H2 formed was more increased by steam reforming of coke and steam gasification of char in steam gasification. The cold gas efficiency of over 70 % was obtained at 958 K in the pyrolyzer, at 1150 K in the gasifier, and 1.6 of S/C which is the ratio of the steam feed rate and the carbon content in the raw fuel.
At present, Japan is even in a bigger energy problem since the oil crisis. Conversion to renewable energy has become an urgent need among many problems in Japan, one in particular, the carbon-dioxide emission that is increasing at an alarming rate. Bio-coke was developed in this laboratory and is reaching commercial level. This study discusses the relationship between the retention time of formed Bio-coke and its specific surface area. During the formation time of about 5 minutes, a specific surface area of 0.5 m2/g is achieved, and a cold compressive strength of 60MPa is attained. When the specific gravity reaches at least 1.395, the specific surface area is reduced to about 0.5 m2/g.
Biomass is one of the sustainable energy sources and is the most suitable natural energy for storage and transport. We are suggesting a high hardness biomass briquette made from any plant biomass as an alternative coal coke. The high hardness biomass briquette is named ‘Bio coke’, described as ‘BIC’ below, and it achieves 10 to 20% substitution of coal coke for practical cupola furnace use. We, in the present study, examined the influence of composition on combustion property of BIC made from coffee residues. The coffee residues were assorted to outer skin (outer skin and pulp mixture, described as ‘OS’ below), inner skin (parchment and silver skin mixture, described as ‘IS’ below) and coffee bean grounds (instant coffee production residue, described as ‘IC’ below). BIC specimens were composed of IC100%, IC50%+OS50% and IC50%+IS50%, OS100% and IS100%. Measurement of ignition delay (time from heating start to flaming combustion start), duration time of flaming combustion and char combustion, and thermogravimetry were conducted under 698K air environment. As a result, the ignition delay and the duration time of char combustion were affected by not only combustion property of each component but crack generation condition during heating process. The ignition delay and the duration time of char combustion were shorten due to enlargement of reaction surface area caused by the crack generation. It is, additionally, considered that the crack generation condition could be controlled by mixing of components which have different thermal decomposition and combustion properties.