Coal desulfurization by low temperature chlorinolysis, phase 1

The reported activity covers laboratory scale experiments on twelve bituminous, sub-bituminous and lignite coals, and preliminary design and specifications for bench-scale and mini-pilot plant equipment

The bactericidal effects of negative ions in air

The use of negative ions to improve indoor air quality has attracted increasing attention in recent years. Although the physical action of air ionisers is accepted, there is still debate over their apparent biocidal action. A recent clinical trial in an intensive care unit suggested that air ionisers may have a role in reducing the transmission of infection in healthcare environments1 and several authors have reported that ions inhibit the growth of a range of microorganisms. A further understanding of this process was gained through bench scale experiments exposing sessile cultures to positive and negative ions2. The aim of the work presented here was to follow on from the bench scale experiments to investigate the efficacy of negative ions with aerosolised microorganisms

Thermochemical Conversion of Biomass in Smouldering Combustion across Scales: the Roles of Heterogeneous Kinetics, Oxygen and Transport Phenomena

AbstractThe thermochemical conversion of biomass in smouldering combustion is investigated here by combining experiments and modeling at two scales: matter (1mg) and bench (100g) scales. Emphasis is put on the effect of oxygen (0–33vol.%) and oxidation reactions because these are poorly studied in the literature in comparison to pyrolysis. The results are obtained for peat as a representative biomass for which there is high-quality experimental data published previously. Three kinetic schemes are explored, including various steps of drying, pyrolysis and oxidation. The kinetic parameters are found using the Kissinger–Genetic Algorithm method, and then implemented in a one-dimensional model of heat and mass transfer. The predictions are validated with thermogravimetric and bench-scale experiments and then analyzed to unravel the role of heterogeneous reaction. This is the first time that the influence of oxygen on biomass smouldering is explained in terms of both chemistry and transport phenomena across scales

Heterogeneous Extractive Batch Distillation of Chloroform - Methanol – Water : Feasibility and Experiments

A novel heterogeneous extractive distillation process is considered for separating the azeotropic mixture chloroform – methanol in a batch rectifying column, including for the first time an experimental validation of the process. Heterogeneous heavy entrainer water is selected inducing an unstable ternary heteroazeotrope and a saddle binary heteroazeotrope with chloroform (ternary diagram class 2.1-2b). Unlike to well-known heterogeneous azeotropic distillation process and thanks to continuous water feeding at the column top, the saddle binary heteroazeotrope chloroform – water is obtained at the column top, condensed and further split into the liquid – liquid decanter where the chloroform-rich phase is drawn as distillate. First, feasibility analysis is carried out by using a simplified differential model in the extractive section for determining the proper range of the entrainer flowrate and the reflux ratio. The operating conditions and reflux policy are validated by rigorous simulation with ProSim Batch Column® where technical features of a bench scale distillation column have been described. Six reproducible experiments are run in the bench scale column matching the simulated operating conditions with two sequentially increasing reflux ratio values. Simulation and experiments agree well. With an average molar purity higher than 99%, more than 85% of recovery yield was obtained for chloroform and methanol

PILOT-SCALE CONSTRUCTED WETLAND TREATMENT SYSTEM FOR AMMONIA REMOVAL FROM OIL-FIELD PRODUCED WATER

This investigation examined the feasibility of using free-water surface constructed wetland systems (CWTSs) to decrease the ammonia concentration in oil-field produced water. The objective of this research was to design constructed wetland experiments to determine specific conditions that decrease aqueous ammonia concentrations in simulated oilfield produced water. The design of these experiments was based on biogeochemical pathways of nitrification and denitrification. The experiments included three scales: bench-scale, single-cell, and pilot-scale. Bench-scale reactors contained wetland plants (Typha latifolia) and hydrosoil in 5-gallon buckets. Single wetland cells were constructed by adding hydrosoil and plants (T. latifolia and Schoenoplectus californicus) to 70-gallon containers. The pilot-scale CWTS included four constructed wetland series, each consisting of four cells. One series was designed as a control system, and the other three series were designed to test the effects of aeration and organic matter on ammonia removal. Data from bench-scale experiments indicate that ammonia removal was enhanced by the addition of zeolite, organic matter, and shallow (3 to12 inches) water depth. In the single-cell experiments, ammonia removal was enhanced by the addition of sugar to the water as a carbon source for microbial activity. Ammonia removal ranged from 3.3 to 82.6% in the single-cell experiments, with total nitrogen removal of 1.2 to 53.6%. In the pilot-scale CWTS, ammonia removal ranged from 19.2 to 62.5%, and ammonia concentration decreased from 25 mg/L to 7.92 mg/L. To enhance the removal efficiency, sucrose and oyster shells were added to promote conditions favorable for the removal processes in a redesigned pilot-scale CWTS. The redesigned pilot-scale CWTS achieved ammonia removal ranging from 59.9 to 96.8% and a removal extent as low as 0.73 mg/L

Powder towpreg process development

The process for dry powder impregnation of carbon fiber tows being developed at LaRC overcomes many of the difficulties associated with melt, solution, and slurry prepregging. In the process, fluidized powder is deposited on spread tow bundles and fused to the fibers by radiant heating. Impregnated tows have been produced for preform, weaving, and composite materials applications. Design and operating data correlations were developed for scale up of the process to commercial operation. Bench scale single tow experiments at tow speeds up to 50 cm/sec have demonstrated that the process can be controlled to produce weavable towpreg. Samples were woven and molded into preform material of good quality

Adsorption of Perfluorinated Compounds from Post-Emergency Response Wastewater

This research investigated the efficacy of granular activated carbon (GAC) as a method to treat water impacted with aqueous film forming foam (AFFF) after a firefighting response. Bench-top experiments were conducted and compared to field scale adsorber performance removing mg/L concentrations of PFAS in water contaminated with Military Specification AFFF. Batch tests compared four adsorbents, and determined Calgon F600 GAC and Rembind Plus mixed carbon media had the greatest perfluorooctane sulfonate (PFOS) capacities. Additional batch isotherm experiments using AFFF and higher PFOS concentrations (mg/L) indicated larger amounts of GAC are required (\u3e30mg/L) for effective removal. Full-scale testing simulated an expedited means of treating AFFF impacted waters with Calgon Flowsorb drums containing F600 GAC and effectively removed PFAS below detection limits for 4,365 gallons of water. Bench-top flow-through experiments used rapid small-scale columns (RSSCTs) to predict full-scale treatment performance. RSSCT experiments exceeded full-scale capacity and breakthrough to 10%, 50% and 75% of influent PFOS concentrations were observed at 577, 1173 and 2215 bed volumes. Toxicity testing indicated AFFF impacted water and treated RSSCT effluent have no adverse, short-term impact on microbial health in activated sludge. The results will be used to determine effective emergency response treatment techniques

Modeling, Evaluating and Scaling up a Commercial Multilayer Claus Converter Based on Bench Scale Experiments

Industrial scale reactors work adiabatically and measuring their performance in an isothermal bench scale reactor is faced with uncertainties. In this research, based on kinetic models previously developed for alumina and titania commercial Claus catalysts, a multilayer bench scale model is constructed, and it is applied to simulate the behavior of an industrial scale Claus converter. It is shown that performing the bench scale isothermal experiments at the temperature of 307 ºC can reliably exhibit the activity of catalytic layers of an industrial Claus converter operating at the weighted average bed temperature (WABT) of 289 ºC. Additionally, an adiabatic model is developed for a target industrial scale Claus reactor, and it is confirmed that this model can accurately predict the temperature, and molar percentages of H2S and CS2. Based on simulation results, 20% of excess amount of Claus catalysts should be loaded to compensate their deactivation during the process cycle life. Copyright © 2020 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0).