Effect of Ruthenium and Cerium Oxide (IV) Promotors on the Removal of Carbon Deposit Formed during the Mixed Methane Reforming Process

This work investigates the effect of the addition of Ru and CeO2 on the process of gasification of carbon deposits formed on the surface of a nickel catalyst during the mixed methane reforming process. Activity studies of the mixed methane reforming process were carried out on (Ru)-Ni/CeO2-Al2O3 catalysts at the temperature of 650–750 °C. The ruthenium-promoted catalyst exhibited the highest activity. Carbonized post-reaction catalyst samples were tested with the TOC technique to investigate the carbonization state of the samples. The bimetallic catalyst had the lowest amount of carbon deposit (1.5%) after reaction at 750 °C. The reactivity of the carbon species was assessed in mixtures of oxygen, hydrogen, carbon dioxide, and water. Regardless of the gasifying agent used, the carbon deposit was removed from the surface of the catalytic system. The overall mechanism of mixed methane reforming over Ru and CeO2 was shown.

INVESTIGATION OF PLASMA-OHMIC ELECTRIC FURNACES FOR GASIFYING CARBONACEOUSE WASTES

For the first time, the processes of reducing energy consumption of a plasma-ohmic electric furnace for the gasification of various carbon-containing wastes (municipal, biological, agricultural, and other organic wastes) were investigated. The effect of reducing the humidity, morphological composition of waste on energy consumption during plasma gasification of carbon-containing materials is shown. The possibility to exclude the process of preliminary drying from the production cycle of waste gasification has been revealed. In the modern world, one of the global trends in technology development is the continuous increase in the efficiency and environmental friendliness of carbon-containing waste management methods. The carbon-containing industrial waste includes: municipal (municipal solid waste (MSW)), agricultural (rice husk, etc.), industrial (wood waste, coal slimes, etc.) and biological (medical, biological sludge deposits (BIO) and etc.) Despite the different nature of this waste, they all consist of the same chemical elements: carbon, hydrogen, oxygen, nitrogen, chlorine, sulfur, ash (a complex of inorganic elements and compounds), water (moisture), but contain elements and compounds dangerous for the environment (pathogens, heavy metals, etc.). Gasification of carbon-containing wastes is a complex physico-chemical process with a large number of effects, a complete scientific explanation of which is far from completion.

Parameters of a gas discharge with a liquid electrode in the process of gasification of hydrocarbon-containing waste

A plasma generator with a liquid cathode has been developed and investigated, which makes it possible to create a plasma flow from electrolyte vapors with a temperature of up to 1800°C with a mass flow rate of up to 3.0 g/s for the gasification of carbon-containing waste. An electrolyte in the form of a solution of Glauber salt in distilled water with a concentration of 0.5-1.0 kg/m3 by weight was used. The current-voltage characteristics of the discharge are constructed. The optimal electrical and thermal parameters of the plasma flow are determined experimentally.

Integrated Reduction of the Self–Reducing Pellets on the Blast Furnace

The objective of the present work is to research a quantitate ratio of degree direct reduction inside of SRP and degree of indirect reduction outside of SRP on the top of the blast furnace.The reactions of direct and indirect reduction occurring during the heat treatment of self reducing pellets (SRP) have been studied. In this investigation Blast furnace (BF) sludge which contains particles of coke, has been included in the SRP blend as a source of solid reductant and iron bearing oxides. In the SRP as a part ot the blast furnace burden occur the reactions simultaneously: inside of SRP-direct reduction by Csolid; gasification of carbon and indirect reduction by CO; and outside of SRP-indirect reduction of iron bearing oxides by reducing gas coming from the hearth of blast furnace through the column of charged materials. The experimental setup is shown in Fig. 1. It con-sists of a electrical heating furnace, which can be moved up and down. The quartz tube passes through the furnace. The reaction zone is in the middle of the furnace. Neutral argon atmosphere is created and for indirect reduction argon changed - on hydrogen. Gases of argon, hydrogen are introduced into the furnace separately. Wire of nickel alloy chromosome joins the scales test. A thermocouple is located in the tube.The crucible of wire chrome-nickel was permeable.Metohd. The experiments was performed continuously from the start temperature (~200 ˚C) to the experimental temperature (500 ˚C; 700 ˚C; 900 ˚C; 1100 ˚C) in argon free environment. Upon reaching the desired temperature argon was replaced by hydrogen during 30 minutes. After that the reduced probe of SRP was cooled in argon. Results. The integrated degree of reduction is equal 100%, which includes 98,6 % direct reduction by solid carbon under temperatures 1100°C. The chemical analysis of the reduced SRP showed the degree of integrated reduction change from 85,79 % (900 °C) to 92,50 % (1000 °C) and 84,6% (1100°C) and metallization 83,30 % (900 °C), 89,90 % (1000 °C), 80,75 % (1100 °C).These data correspond to results of degree of reduction SRP depends on temperature

Experimental and Numerical Investigation of Reaction Behavior of Carbon Composite Briquette in Blast Furnace

The application of carbon composite briquette (CCB) is considered to be an efficient method for achieving low-energy and low-CO2-emission blast furnace (BF) operations. In this research, a combined experimental and numerical study was conducted on the CCB reaction behavior in BF. The CCB used in this study had a composition of 20.10 wt.% carbon, 29.70 wt.% magnetite, 39.70 wt.% wüstite, and 1.57 wt.% metallic iron. Using the prepared CCB samples, isotherm reduction tests under a simulated BF atmosphere (CO-CO2-N2) were conducted and a reaction model was developed. Subsequently, the reaction behavior of CCB along the mid-radial solid descending path in an actual BF of 2500 m3 was analyzed by numerical simulations based on the experimental findings and the previous results of comprehensive BF modeling. The results of the experiments showed that the CCB model predictions agreed well with the experimental measurements. With respect to the BF, the results of the numerical simulations indicated that, along the path, before the CCB temperature reached 1000 K, the CCB was reduced by CO in the BF gas; when its temperature was in the range from 1000 to 1130 K, it underwent self-reduction and contributed both CO and CO2 to the BF gas; when its temperature was above 1130 K, it only presented carbon gasification. Moreover, these results also revealed that the reduction of iron oxide and the gasification of carbon inside the CCB proceeded under an uneven mode. The uneven radial distribution of the local reduction fraction and local carbon conversion were evident in the self-reducing stage of the CCB.

Fuel processing in a swirl flow: numerical modelling of combustion and gasification

This study presents the concept of a cyclone furnace for coal dust combustion and gasification under conditions of oxy-fuel combustion. A two-chamber design of the cyclone furnace allows for the separation of the process of heating, drying and devolatilization of fuel from processes of its combustion and gasification of carbon residue. The choice of process parameters helps control fuel gasification. Supplying the driving gas with a specific composition (O2, CO2) to the chamber PC1 ensures the control of temperature and composition of combustible gases obtained through gasification. These gases can be used as a fuel for power boilers and, consequently, allow for utilization of the oxy-fuel combustion technology in new or existing power boilers.