Adsorption by granular activated carbon (GAC) has been widely employed to remove various synthetic organic contaminants (SOCs) from water supplies [1]. A factor complicating the design and effectiveness of activated carbon for the treatment of potable waters is the presence of naturally occurring dissolved organic matter (NOM) in natural waters. The presence of NOM can significantly reduce the ...

This paper represents a detailed techno-economic analysis of typical commercial-scale catalytic decarboxylation process naphthenic acids over HZSM-5 zeolite. Simulation the has been performed in ASPEN Plus®. The performance modeled unit was compared to experimental results data from similar plant. Two models were developed for proposed industrial plant based on continuous flow reactors; first i...

Fixed bed biofilm reactors with granular activated carbon (GAC) or glass beads as support media were used to evaluate the influence of short-term (12h) and long-term (23 days) increases of influent dissolved oxygen (DO) concentrations on biological perchlorate removal. The goal was to evaluate the extent by which chemisorption of oxygen to GAC can enhance the stability of biological perchlorate...

The reductive biotransformation of mercuric ions to elemental mercury was studied by applying a model system with a genetically engineered Pseudomonas putida strain in a lab scale three-phase fluidized bed (TPFB). The aim was to demonstrate the suitability of the TPFB to demercurize effluent streams containing up to 10 mg Hg2+ dm(-3). The TPFB is used, first, to carry out the biotransformation ...

This work studied the influence of effluent recirculation upon the kinetics of anaerobic degradation of dairy wastewater in the feedless phase of intermittent upflow anaerobic sludge bed (UASB) reactors. Several laboratory-scale tests were performed with different organic loads in closed circuit UASB reactors inoculated with adapted flocculent sludge. The data obtained were used for determinati...

Trickle bed reactors are governed by equations of flow in porous media such as Darcy’s law and the conservation of mass. Our numerical method for solving these equations is based on a total-velocity splitting, sequential formulation which leads to an implicit pressure equation and a semi-implicit mass conservation equation. We use high-resolution finite-difference methods to discretize these eq...

Although the operation under unsteady state is generally avoided and continuous operation is preferred in the chemical industry, this mode of operation can often lead to a better performance. Because of this, forced unsteady state reactors are object of increasing interest. In particular, the systems based on the periodic reversal of the feed flow direction, called reverse flow reactors (RFR), ...

Hydrogen was produced by steam reforming of dimethyl ether (DME) using a physical mixture of commercial HZSM-5 zeolite (for DME hydrolyzing) and Cu/ZnO/Al2O3 (for methanol steam reforming) as a catalyst in a fixed bed reactor. The experiments were performed at atmospheric pressure and in a temperature range from 270 to 310 °C. The effects of feed temperature and gas hourly space velocity (GHSV)...

MIT has been developing a conceptual design for pebble bed reactors since approximately 1998, when a student design project concluded that in order to resurrect the nuclear power industry a new, innovative approach was needed, not only in reactor design but also in construction and operation. In their quest to identify the appropriate technology several key conclusions were reached. First was t...