Article

Low temperature dry scrubbing reaction kinetics and mechanisms, Volume 1

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Dry scrubbing that takes place after the air preheater (

Simulation and Optimization of a Granular Limestone Flue Gas Desulfurization Process

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Jan 1998

This chapter presents a process simulation model developed for the Limestone Emission Control process. The process involves contacting flue gas with a densely packed, wet bed of granular limestone. The process model includes the chemistry, mass transfer, and heat transfer associated with this system along with sorbent screening and recycle steps occurring outside the scrubber. Approximate cost correlations are applied to various system components and used to drive a design optimization for four different cases corresponding to two levels of sulfur capture and two levels of sulfur content in the coal. The results indicate that this technology is best suited for high-sulfur, small-scale applications. Future experimental work should evaluate the use of larger (1/4 inch) sorbent.

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Low Temperature Kinetics of the First Steps of Water Cluster Formation

March 2016 · Physical Review Letters

We present a combined experimental and theoretical low temperature kinetic study of water cluster formation. Water cluster growth takes place in low temperature (23-69 K) supersonic flows. The observed kinetics of formation of water clusters are reproduced with a kinetic model based on theoretical predictions for the first steps of clusterization. The temperature- and pressure-dependent ... [Show full abstract] association and dissociation rate coefficients are predicted with an ab initio transition state theory based master equation approach over a wide range of temperatures (20-100 K) and pressures (10^{-6}-10 bar).

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Effective estimation of parameters in biocatalytic reaction kinetic expressions are very important when building process models to enable evaluation of process technology options and alternative biocatalysts. The kinetic models used to describe enzyme-catalyzed reactions generally include several parameters, which are strongly correlated with each other. State-of-the-art methodologies such as ... [Show full abstract] nonlinear regression (using progress curves) or graphical analysis (using initial rate data, for example, the Lineweaver-Burke plot, Hanes plot or Dixon plot) often incorporate errors in the estimates and rarely lead to globally optimized parameter values. In this article, a robust methodology to estimate parameters for biocatalytic reaction kinetic expressions is proposed. The methodology determines the parameters in a systematic manner by exploiting the best features of several of the current approaches. The parameter estimation problem is decomposed into five hierarchical steps, where the solution of each of the steps becomes the input for the subsequent step to achieve the final model with the corresponding regressed parameters. The model is further used for validating its performance and determining the correlation of the parameters. The final model with the fitted parameters is able to describe both initial rate and dynamic experiments. Application of the methodology is illustrated with a case study using the ω-transaminase catalyzed synthesis of 1-phenylethylamine from acetophenone and 2-propylamine. © 2012 American Institute of Chemical Engineers Biotechnol. Prog., 2012.

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The condensation of trimethylolphenol

June 1983 · Journal of Polymer Science Polymer Chemistry Edition

Robert T. Jones

The intermolecular condensation reactions of 2,4,6-trimethylolphenol (TMP) have been studied. The rate of disappearance of TMP from aqueous solutions at 40°C was measured over a range of pH 2–11. Concentrations of TMP were determined by HPLC. Major products, separated on the chromatograph and identified by PMR, were the o,p- and p,p-dimers and a trimer. Reaction kinetics were second order in TMP ... [Show full abstract] concentration at low pH. At high pH kinetics were first order in total TMP concentration, contrary to the findings of earlier investigators. The reaction rate varied with pH in a complex manner. The variation is explained by separate acid-catalyzed and base-catalyzed mechanisms. A kinetic model is proposed in which the rate constants are independent of pH.

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Combined thermodynamic and kinetic models for processing of materials

January 2001

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Kinetics of colour change of kiwifruits during hot air drying

May 2001 · Journal of Food Engineering

Medeni Maskan

The kinetics of colour changes of kiwifruits, due to drying by hot air, microwave (MW) and hot air–MW finish drying, were studied. Kinetic parameters for the colour change were determined using Hunter L-, a-, b-values, chroma, Hue, total colour difference and browning index (BI) values. The drying process changed all three colour parameters (L, a, b), causing a colour shift towards the darker ... [Show full abstract] region. Parameters L and b decreased and a-value increased during drying. The Hunter parameters were more influenced by MW drying. Zero- and first-order kinetic models were applied to describe colour change. Both models were found to describe the L- and b-data adequately. However, a-values and ΔE followed zero-order and whole data of hot air–MW drying followed first-order kinetics.

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Low-temperature dry scrubbing reaction kinetics and mechanisms : limestone dissolution and solubilit...

January 1970

Michael. Maldei

Thesis (M.S.)--Ohio University, June, 1993.

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Kinetic analysis and process modeling for cellulose valorization in cooperative ionic liquid pairs

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March 1981 · Berichte der Bunsengesellschaft für physikalische Chemie

The mechanism of the cistrans-photoisomerization was investigated. Quantum yields of nearly unity were observed at temperatures around 180 K indicating that a twisting of the molecule excited into its S1-state occurs. A detailed analysis has shown that both, an isomerization via the singlet as well as via the triplet state is possible. A kinetic model has been proposed which describes ... [Show full abstract] quantitatively the experimental results.

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January 1990

Albert Renken

An exptl. set-up for the simultaneous detn. of reactant concn. in the gas phase and on the surface by spectroscopic methods was proposed to obtain information on the intrinsic kinetics of unsteady-state processes undergoing heterogeneous catalysis. The hydrogenation of CO and CO2 and the effect of the water-gas shift were discussed. Transient expts. were not always sufficient for model ... [Show full abstract] discrimination. Among models describing steady-state and transient behavior of the addn. of AcOH to C2H4 and of elimination reactions, model discrimination was possible only on the basis of forced concn. expts. [on SciFinder (R)]

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January 2018

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