Seiichi Deguchi

Combustion of refuse derived fuel in a fluidized bed

Power generation from Refuse Derived Fuel (RDF) is an attractive utilization technology of municipal solid waste. To explain the behavior of RDF-fired fluidized bed incinerator, the commercial size RDF was continuously burnt in a 30×30 cm bubbling type fluidized-bed combustor. It was found that 12 kg/h of RDF feed rate was too high feed for this test unit and the CO level was higher than 500 ppm. However, 10 kg/h of RDF was a proper feed rate and the CO level was kept under 150 ppm. Secondary air injection and changing air ratio from the pipe grid were effective for the complete combustion of RDE. It was also found that HCl concentration in flue gas was controlled by the calcium component contained in RDF and its level was decreased with decreasing the combustor temperature.

FORMATION MECHANISM OF Tio2 FINE PARTICLES PREPARED BY THE SPRAY PYROLYSIS METHOD

ABSTRACT Fine particles of Tio2 were prepared from titanyl sulfate solution by the Spray pyrolysis Method( SPM) The reaction tube was divided into four zones: drying, dehydration, pyrolysis 1 and pyrolysis 2 zones. Under various reaction temperature and carrier gas flow rate, the mean size and the size distribution of particles collected at different sampling positions along the axial direction of the reactor were compared. The effects of operating conditions of drying, dehydration and subsequent pyrolysis steps on the formation mechanism of Tio2 fine particles were discussed

Simulation for solid concentration profile in CFB with different fluid/solid density ratios

One of the fundamental functions of a circulating fluidized-bed reactor is the dense suspension of particles in violent agitation, and the performance of the reactor depends largely on the particle concentration. It is thus necessary to estimate the solid concentration profile for the design of fast fluidization reactors. Although the influence of pressure or the density ratio between fluid and solid on the particle concentration in the circulating fluidized bed has been experimentally investigated, it has not yet been fully understood theoretically. Not a few plant development units now in operation have, however, been designed on empirical experiences supported by basic experiments. The purpose of this paper is to clarify the influence of the fluid/solid density ratio on the vertical concentration profile by application of the Growing Chain Model. It is found that the distance from the riser top to the point where solid concentration attains actually its final value, decreases with increase in the fluid/solid density ratio, thus making the bed more uniform vertically. The final concentration is independent of the fluid/solid density ratio. These findings coincide with some experiments by other investigators.

NO reduction and the formation of nitrogen compounds over a metal-supported three-way catalyst

Abstract The fundamental characteristics of NO reduction and the formation of nitrogen compounds such as N 2 O, NH 3 and HCN were investigated on a metal-honeycomb-supported three-way catalyst. Experiments were carried out in a quartz glass tube reactor by flowing simulated gas mixtures in the NO/H 2 /Ar, NO/CH 4 /Ar and NO/CO/Ar systems. In the NO/H 2 /Ar system, NO reduction began at the lowest temperature of all the systems examined. In any system, the conversion ratio of NO reduction was over 90% at gas temperature higher than 900 K. However, depending on temperature, NO reduction resulted in nitrogen-compound formation as NH 3 in the NO/H 2 /Ar system, HCN in the NO/CH 4 /Ar system, and N 2 O in all systems. In particular, N 2 O formation was dominant at relatively low temperature. The effect of the coexistence of the oxygen on NO reduction was also examined and a sufficient conversion was observed if the O 2 concentration was less than 1 vol%.

Thermal Energy Storage, Heat Pump and Thermal Energy Transportation Technologies. Solid Mixing Behavior in Bubbling Fluidized Beds.

流動層の軸方向および水平方向の粒子混合特性を調べるため, 矩形流動層を用いてトレーサー粒子の濃度変化の測定をおこなった.実験は, 粒子挙動が二次元とみなせる流動層を用い, 壁面をCCDカメラで撮影し, その画像をイメージデジタイザーで解析することにより流動層内粒子混合の測定を行った.また, 粒子径の混合に及ぼす影響について調べるため, 2種類の粒子径を選択し実験を行った.その結果, 流動化直後層内に大きな渦状の粒子循環流の形成がみられ, 層内での粒子混合は, 層壁近傍においてその層内粒子大循環流の影響を大きく受けていることがわかった.また, 層中心部および層下部においては気泡の移動に伴う混合が支配的であることがわかった.