C.M. Kinoshita

An experimental investigation of hydrogen production from biomass gasification

Abstract An experimental study of hydrogen production from biomass was conducted using a benchscale fluidized bed gasifier. Parametric experiments were performed to determine the effects of reactor temperature, equivalence ratio, and steam to biomass ratio. Experimental measurements of gas composition and yield were used to calculate the hydrogen yield potential, the capacity of the gas stream for hydrogen production by shifting carbon monoxide and steam reforming higher hydrocarbons. Over the ranges of experimental conditions examined, hydrogen yield potential proved to be most sensitive to equivalence ratio, varying from 62 g H2 kg−1 of dry, ash-free biomass at an equivalence ratio of 0.37, to 128 g H2 kg−1 of dry, ash-free biomass at an equivalence ratio of 0.0. Of the conditions tested, the highest hydrogen yield potential, 128 g H2 kg−1 of dry, ash-free biomass, was achieved at a reactor temperature of 850 °C, equivalence ratio of 0.0, and a steam to biomass ratio of 1.7. This is 78% of the theoretical maximum yield of 165 g H2 kg−1 of dry, ash-free biomass for this feedstock.

Tar formation under different biomass gasification conditions

Abstract Parametric tests on tar formation, varying temperature, equivalence ratio, and residence time, were performed on a bench-scale, indirectly-heated fluidized bed gasifier. Prepared tar samples were analyzed in a gas chromatograph (GC) with a flame ionization detector, using a capillary column. Standard test mixtures containing the dominant tar species were prepared for GC calibration. The identified peaks included single-ring hydrocarbons, such as benzene, to five-ring hydrocarbons, such as perylene; these compounds represent about 70–90% (mass basis) of the tar constituents. The influences of the above-mentioned gasification parameters on tar formation were analyzed.

The fate of inorganic constituents of biomass in fluidized bed gasification

Bagasse and four banagrass fuels with different inorganic fractions were gasified in a bench-scale fluidized bed at a nominal equivalence ratio of 0.3, reactor temperature of 800°C and atmospheric pressure. The gasifier output stream was characterized for permanent gas species, ammonia, condensable hydrocarbon species, char content and composition, and gas-phase inorganic species concentrations. Gas-phase concentrations of K, Na and Ca exceeded combustion turbine fuel specifications. Si, Fe, P, and Cl were also present in the gas phase. Significant amounts of inorganic fuel constituents were retained in the fluidized bed, dispersed over the surface of the bed particles.

Thermochemical production of methanol from biomass in Hawaii

Sufficient trees or grasses can be grown in Hawaii and converted into enough methanol to replace all of the gasoline and diesel fuel consumed in the State for ground transportation. A recent Hawaii Natural Energy Institute study shows that methanol can be produced from biomass via partial oxidation for

Solubility of CO2 in the ocean and its effect on CO2 dissolution

0·16 liter-1 (wholesale price at the plant gate), based on a 760 million liter per year (MLPY) methanol plant processing 7000 tonnes day-1 of biomass feedstock (50% moisture content) from a recurring annual harvest of approximately 36 000 hectares of intensively managed, short-rotation energy crops. The capital cost of this methanol-from-biomass facility would be roughly

An experiment to simulate ocean disposal of carbon dioxide

280 million. Sufficient hydrogen added to the synthesis gas to convert all of the biomass carbon into methanol carbon would more than double the methanol produced from the same biomass base, yielding 1700 MLPY at

Hawaii: An International Model for Methanol from Biomass

0·28 liter-1 at a capital cost of

Pre-combustion removal of carbon dioxide from hydrocarbon-fuelled power plants

335 million.

Dispersion of CO2 droplets in the deep ocean

Abstract The rate of mass transfer from pure CO 2 effluent discharged in the deep ocean depends strongly on the solubility of CO 2 in seawater. This thermodynamic study derives solubility relationships for both gas- and liquid-phase CO 2 in seawater. It is determined that, for CO 2 gas, solubility depends on both temperature and pressure and, as a consequence, solubility increases sharply with depth in the ocean. For CO 2 liquid, solubility depends only on temperature and increases slowly with depth, approaching near constant values in the deep ocean. These results are applied to examine dissolution rates of CO 2 bubbles and droplets.

Flame Luminosity of Methanol/Additive Fuel Mixtures

Experiments have been initiated in a novel facility to assess the feasibility of marine sequestration of anthropogenic carbon dioxide. Experiments will attempt to elucidate the mechanism that describes the mixing of liquid carbon dioxide and high-pressure seawater. This information will be used to model the fate of carbon dioxide injected into the archibenthic zone. The facility comprises a fully-instrumented pressure vessel that can simulate conditions at depths up to about 600 m below the ocean surface. Pure liquid carbon dioxide is injected through an orifice near the bottom of the vessel. Experimental parameters that can be varied in this facility include simulated depth of discharge, jet diameter and geometry, jet velocity, and liquid carbon dioxide temperature. Measurements of scalars and velocity in the near-field mixing region are obtained with a traversing, multiple sensor probe rake. Numerous viewports in the vessel wall provide access for flow visualization studies. Preliminary observations suggest that, in the majority of injection scenarios, the carbon dioxide jet will break up into a spray of droplets near the discharge point. Solid hydrates were observed to form very slowly and appeared to be buoyant, possibly as a result of the trapping of vapor or liquid CO2 in the interstices of the solid phase.