Mathematical modelling of a staged pulverized coal gasification using O2/CO2 mixtures

Conversion of pulverized coal in a two-stage gasifier is studied. When considering carbon capture power plants, mixtures of oxygen with carbon dioxide may be used as a gasification agent. Carbon dioxide is a gasification agent, so characteristics of the gasification process change significantly compared to gasification in oxygen-nitrogen mixtures. The conversion efficiency is determined by the thermophysical factor (change in the heat capacity of the gas mixture and transfer coefficients) and the concentration factor (increase in the concentration of the gaseous reagent). The ratio of primary and secondary fuel consumption determines the leading stage of the process. The influence of process efficiency on oxygen concentration is estimated in the range of 21–30 vol. %.

FACTORS AFFECTING THE INTENSITY OF LEADING TARNED DISPLAYED GLASS BY FLUOROCHLORINE-CONTAINING GAS-SHAPING REAGENTS

The aim of the undertaken experiments was to determine the factors affecting the process of dealkalization of container colorless glass with fluorine–and chlorine–containing gaseous reagents.The subjects of investigation were various types containers (bottles, jars and flasks) of colorless glass. Hydrogen chloride, difluorodichloro-methane and difluorochloromethane and mixtures of these reagents with sulfur dioxide were used for the chemical treatment of glass. We have investigated the influence of the following factors on the process of dealkalization of container colorless glass with fluorine–and chlorine–containing reagents: temperature, chemical compositions of the gas medium, duration of the thermochemical treatment, concentration and humidity of gaseous reagent, re-peated thermal treatment and surface state of the samples

Design and 3D printing of a stainless steel reactor for continuous difluoromethylations using fluoroform

The design and 3D printing of a stainless steel reactor for reaction with a gaseous reagent is described.

Measurement of Total Free Iron in Soils by H2S Chemisorption and Comparison with the Citrate Bicarbonate Dithionite Method

Free iron is one of the major analytical items for soil basic properties. It is also an important indicator for understanding the genesis of soil, soil classification, and soil distribution behavior. In this study, an alternative analytical method (chemisorption) based on thermodynamic knowledge was proposed for measurement of total free iron oxides in soils. Several representative soil samples belonging to alfisols, ultisols, inceptisols, and entisols were collected from Taiwan and tested by the chemisorption, and the estimated total free iron oxides were compared with those measured from the traditional citrate bicarbonate dithionite (CBD) method. Experimental results showed that the optimal operating temperature was found to be at 773 K and the carbon monoxide (CO) is the best gaseous reagent to promote the formation of FeS. The estimated total free iron oxides for soil samples determined from the chemisorption in the presence of CO were very close to those from the CBD technique. The result of regression indicates that the estimated total free iron is strongly correlated with the CBD-Fe content (R2=0.999) in the presence of CO.

Experimental Study on SHS under High Nitrogen Pressure

Gas-solid systems are among a large class of systems in which self-propagating hightemperature synthesis (SHS) is observed. Powders of metals and non-metals burn in the atmosphere of gaseous reagent and the products of the reaction are solid. A variety of nitrides and different composites were synthesized by combustion of porous powder compacts in nitrogen atmosphere. The conversion, achieved during the combustion process, as well as the composition and structure of the products, significantly depends on the nitrogen pressure. Most of the published experimental results on this topic were obtained under nitrogen pressure of less 10 MPa and only few systems were investigated under higher pressures. In this work we present the results of the studies on the combustion process in the range of high nitrogen pressures of 40-400 MPa for two systems, such as Nb-N2 and B-C-N2. Dependences of combustion characteristics, phase composition and microstructure of the synthesized products on the nitrogen pressure were studied.