This study (1) investigates the neutronic characteristics of the Pebble Bed Advanced High Temperature Reactor (PB-AHTR); (2) compares the PB-AHTR neutronic performance against those of the alternative design options of He-cooled high temperature reactors using either pebble (PBMR) or prismatic (VHTR) fuel and against a liquid-salt cooled design version of the latter (LS-VHTR); (3) studies the p...

Background and purpose:Moving Bed Biofilm Reactor is an aerobic attached growth with better biofilm thickness control, lack of plugging and lower head loss. Consequently, this system is greatly used by different wastewater treatment plants. High TDS wastewater produced petrochemical, leather tanning, sea food processing, cannery, pickling and dairy industries. The aim of this study was to evalu...

A silicon differential microchemical reactor that utilizes a novel crossflow geometry has been developed for the testing of porous supported catalysts. The cross-flow design reduces pressure drop by using a shallow but wide catalyst bed. Modeling, flow visualization, and pressure drop studies confirm even flow distribution across the reactor. Kinetic experiments with the oxidation of carbon mon...

In this research work, hydrodynamic characteristics and gas–liquid mass transfer in a laboratory scale inverse turbulent bed reactor were studied. In order to characterize internal flow in the reactor, the residence time distribution (RTD) was obtained by the stimulus-response technique using potassium chloride as a tracer. Different solid hold-up (0–0.37) and air superficial velocity (2.7–6.5 ...

A three-phase nonisothermal heterogeneous model for describing the hydrotreating reactions in a trickle-bed reactor with complete catalyst wetting was solved. It includes correlations for determining solubility data, mass-transfer coefficients, and properties of the compounds under operating conditions. The model, based on the two-film theory and mass-transfer resistance at the gas-liquid and l...

Carbon monoxide (CO) can be metabolized by a number of microorganisms along with water to produce hydrogen (H2) and carbon dioxide. National Renewable Energy Laboratory researchers have isolated a number of bacteria that perform this so-called water-gas shift reaction at ambient temperatures. We performed experiments to measure the rate of CO conversion and H2 production in a trickle-bed reacto...

Two bench-scale parallel moving bed biofilm reactors (MBBR) were operated to assess pH-associated anammox activity changes during long term treatment of anaerobically digested sludge centrate pre-treated in a suspended growth partial nitrification reactor. The pH was maintained at 6.5 in reactor R1, while it was allowed to vary naturally between 7.5 and 8.1 in reactor R2. At high nitrogen loads...

This study investigated the effect, on reactor performance and biomass retention inside the bed, of the material used to make the supports of anaerobic fixed-bed reactors. Three inert supports of similar shape but made of three different materials polyvinyl chloride, polypropylene, high-density polyethylene were manufactured and used. All three supports had the same specific surface area but di...

After the first life cycle of plastics various recycling processes are available for further utilization of these valuable materials. For an ecologically and economically satisfying solution the most suitable process has to be chosen. In chemical recycling polymers are degraded to basic chemical substances which can be reused in the petrochemical industry. For soiled waste plastics or waste pla...