A hybrid quantum mechanical and molecular mechanical potential is used in Monte Carlo simulations to examine the solvent effects on the electronic excitation energy of the n → π(*) transition of acetone in ambient and supercritical water fluid, in which the temperature is in the range of 25-500 °C with pressures of 1-2763 atm. In the present study, the acetone molecule is described by the AM1 H...

Gasification of several types of biomass has been conducted in a fluidized bed gasifier at atmospheric pressure with steam as the fluidizing medium. In order to obtain the gasification profiles for each type of biomass, an artificial neural network model has been developed to simulate this gasification processes. Model-predicted gas production rates in this biomass gasification processes were c...

Demineralization of coals and coal-derived chars is part of an effort to developalternative fuels from coal. Pyrolysis and some gasification processes yieldchars containing a large fraction of the calorific value of the feed coal andessentially all of its mineral matter. In the work reported here, three gasifi-cation chars produced from anthracite, bituminous, and subbitumin...

An inelastic neutron scattering experiment has been performed on supercritical water at high momentum transfer, up to 90 Å, in order to study single proton dynamics. The value of the proton mean kinetic energy has been extracted in the framework of the impulse approximation. The anisotropy of the proton momentum distribution inside a single water molecule is discussed. The extracted experimenta...

Decentralized water reclamation is emerging as a new paradigm that pairs local wastewater resources with local users; however, one of the challenges that must be addressed to advance its implementation is the low energy efficiency associated with small treatment plants and the lack of available small-scale energy recovery technologies. Gasification is a technology that could be used to convert ...

Supercritical water oxidation has attracted attention of many researchers ever since the ideahas emerged about three decades ago as a promising technique in the waste managementindustry. Providing more details about the behavior of a supercritical water oxidation systemunder various operating conditions and extending available data can greatly assist more accurateand reliable design of such sys...

We study the hydrogen bonding structure of water models at supercritical conditions by molecular dynamics to directly compare with recent microstructural data obtained by neutron diffraction with isotopic substitution (NDIS) experiments. We also study the angular dependence of the hydrogenoxygen pair distribution function to gain insight into the hydrogen bonding mechanism in the molecular mode...

Molecular dynamics (MD) calculations have been performed to determine equilibrium structure and properties of systems modeling supercritical (SC) water and SC aqueous solutions at two states near the critical point using the simple point charge (SPC) potential model of Berendsen et al. for water. Both thermodynamic and dielectric properties from the simulations for pure water are accurate in co...

The cleavage of C-S linkages plays a key role in fuel processing and organic geochemistry. Water is known to affect these processes, and several hypotheses have been proposed, but the mechanism has been elusive. Here we use both experiment and theory to demonstrate that supercritical water reacts with intermediates formed during alkyl sulfide decomposition. During hexyl sulfide decomposition in...