Hydrogen production from coke oven gas using pressure swing adsorption processaA mathematical modelling approach

Coal is playing a major role as a reductant and as an energy source in the present world steel production due to its low cost and widespread distribution around the world. At the same time, being the largest contributor to global CO2 emissions, coal faces significant environmental challenges in terms of air pollution and global warming....

Predicting the influence of combined oxygen and glucose gradients based on scale-down and modelling approaches for the scale-up of penicillin fermentations

In large scale fermentors the cultivated cells are exposed to dynamic changes in the nutrient concentrations due to imperfect mixing. Based on the characterization of these nutrient gradients in space and time, a rational scale down design can be obtained. This study focuses on the combined gradients of dissolved sugar and oxygen...

Elimination of aromatic fusel alcohols as by-products of Saccharomyces cerevisiae strains engineered for phenylpropanoid production by 2-oxo-acid decarboxylase replacement

Engineered strains of the yeast Saccharomyces cerevisiae are intensively studied as production platforms for aromatic compounds such as hydroxycinnamic acids, stilbenoids and flavonoids. Heterologous pathways for production of these compounds use L-phenylalanine and/or L-tyrosine, generated by the yeast shikimate pathway, as aromatic...

Molecular Modeling Study to the Relation between Structure of LPEI, Including Water-Induced Phase Transitions and CO₂Capturing Reactions

A molecular modeling study was carried out on linear polyethyleneimine (LPEI) to determine the CO2 capturing process taking into account structural changes of the material at various amounts of H2O. Until now, CO2 capture by LPEI was described as a combination of carbamic and carbonic acid formation. It was found that humidification below the...

Molecular Modeling Study of the SO₂Deactivation of an Amine Resin and a Procedure to Avoid SO₂Deactivation Using a Polyethylene Glycol/Tertiary Amine System

Since 2012, the polymeric resin Lewatit R VP OC 1065 has been investigated for removal of CO2 from various process streams and air. The present article focuses on the deactivation mechanism of the resin with SO2 and a work around. This is important for CO2 capture from flue gas of coal-fired power plants and fuel oil. The deactivation of the...

Direct air capture of CO₂ with an amine resin: A molecular modeling study of the oxidative deactivation mechanism with O₂

Lewatit R VP OC 1065 is a promising material for direct air capture of CO₂. However, it was found that serious oxidative degradation already started from 80 °C. In this DFT study, oxidative degradation is described as a series of well-known reactions in air-oxidation chemistry. Oxidation of the resin starts with the formation of an...

Direct air capture of CO₂ with an amine resin: A molecular modeling study of the deactivation mechanism by CO₂

Since 2012, Lewatit R VP OC 1065 was reported as a promising material for direct air capture of CO₂. However, deactivation at a high pressure of CO₂ at 120 °C was reported with detrimental effects on its application. In this study, using density functional theory calculations, a quantitative description of the...

Molecular modeling study toward development of H₂S-free removal of iron sulfide scale from oil and gas wells

A common problem that faces the oil and gas industry is the formation of iron sulfide scale in various stages of production. Recently an effective chemical formulation was proposed to remove all types of iron sulfide scales (including pyrite), consisting of a chelating agent diethylenetriaminepentaacetic acid (DTPA) at high pH using potassium...

Development of efficient formulation for the removal of iron sulphide scale in sour production wells

Iron sulphide scale, which exists in different forms, is common in sour oil and gas production wells. Iron sulphide hard scales are difficult to remove with acids, requiring mechanical intervention or the replacement of the production tubing. An environmentally friendly formulation with a high pH is proposed for the removal of both soft and...

Solubility of sulfur compounds in commercial physical solvents and an ionic liquid from Monte Carlo simulations

Natural gas, synthesis gas, and flue gas typically contain a large number of impurities (e.g., acidic gases), which should be removed to avoid environmental and technological problems, and to meet customer specifications. One approach is to use physical solvents to remove the acidic gases. If no experimental data are available, the solubility...

Thermodynamic and transport properties of crown-ethers: Force field development and molecular simulations

Crown-ethers have recently been used to assemble porous liquids (PLs), which are liquids with permanent porosity formed by mixing bulky solvent molecules (e.g., 15-crown-5 ether) with solvent-inaccessible organic cages. PLs and crown-ethers belong to a novel class of materials, which can potentially be used for gas separation and storage, but...

Direct air capture of CO₂  with an Amine Resin: A molecular modeling study of the CO₂ capturing process

Several reactions, known from other amine systems for CO2 capture, have been proposed for Lewatit R VP OC 1065. The aim of this molecular modeling study is to elucidate the CO2 capture process: the physisorption process prior to the CO2-capture and the reactions. Molecular modeling yields that the resin has a structure with benzyl amine groups...

Atomistic understanding of cation exchange in PbS nanocrystals using simulations with pseudoligands

Cation exchange is a powerful tool for the synthesis of nanostructures such as core–shell nanocrystals, however, the underlying mechanism is poorly understood. Interactions of cations with ligands and solvent molecules are systematically ignored in simulations. Here, we introduce the concept of pseudoligands to incorporate cation-ligand-solvent...

A thin-film silicon/silicon hetero-junction hybrid solar cell for photoelectrochemical water-reduction applications

A hybrid tandem solar cell consisting of a thin-film, nanocrystalline silicon top junction and a siliconheterojunction bottom junction is proposed as a supporting solar cell for photoelectrochemical applications.Tunneling recombination junction engineering is shown to be an important consideration indesigning this type of solar cell. The best...

Correlation between quantumchemically calculated LUMO energies and the electrochemical window of ionic liquids with reduction-resistant anions

Performing runtime evaluation together with design time exploration enables a system to be more efficient in terms of various design constraints, such as performance, chip area, and power consumption. rSesame is a generic modeling and simulation framework, which can explore and evaluate reconfigurable systems at both design time and runtime. In...

Application of reliability-based flood defence design in the UK