Analysis of Rational Proportion of Raw Materials Based on Biomass

Most of the air pollutants in the steel industry come from the sintering process, and the air pollutants produced by the sintering process mainly come from the sinter fuel (coke breeze). The S and N content of biomass fuel is low; therefore, biomass fuel is used instead of coke breeze for sintering to reduce the emission of the sinter flue gas pollutants. However, the use of biomass fuel reduces the sintering layer temperature, which results in the deterioration of the sinter properties. In order to ensure the quality of sintering base on biomass fuel, the thermodynamic calculation and related experiments were carried out, the effects of different basicity, MgO and Al2O3 content on the formation of low melting point minerals in sintered mixture were studied, and the suitable composition of sintered mixture was determined in this paper, so as to reduce the liquid phase formation temperature of sinter and increase in biomass fuel addition, which provided theoretical support for the application of biomass fuel in sintering. Experimental results indicate that the suitable conditions for the low-temperature sintering were a basicity of 2.0, and MgO and Al2O3 contents of 1.0% and 1.8%, respectively. Under this condition, more biomass fuel can be used to replace coke breeze, and the emission of flue gas pollutants can be greatly reduced.

ENERGY SAVING TECHNOLOGIES IN THE IMPLEMENTATION OF CATHODIC PROTECTION OF PIPELINES AND TANKS

The data on the introduction of new energy-saving technologies of cathodic protection – the installation of magnetite ground electrodes, the use of new activators based on coke breeze, a pulse converter for automatic control of cathodic protection objects are considered. Practical results show that the use of magnetite anodes allows maintaining a high permissible current density, therefore, it is suitable for widespread use in various soils and seawater. The rate of dissolution of magnetite is 0.02 kg / (A • year). Magnetite anodes are also successfully used for the repair of GAZ wells (deep earthing conductors made of metal pipes). To perform this type of work, a typical project has been developed, which allows restoring the operability of deep anode grounding with minimal costs and without the use of expensive drilling operations. The use of activated coke breeze significantly reduces the transition resistance of the anode grounding. It has been practically proven that when using a coke-mineral activator, the transition resistance is significantly reduced due to an increase in the electrical conductivity of the filler at the anode space, the geometric dimensions and current of the diverting object increase, and the transition resistance of the anode - ground is stabilized. LLC "Elmet" has developed a pulse converter of automatic control IPAU designed to convert alternating current into rectified direct current with the possibility of automatic adjustments in several parameters. The basis of the converters is a high-frequency transistor inverter, developed on the basis of the latest achievements in power electronics. The use of stations of the IPAU type with telemetry allows to reduce labor costs for their maintenance in accordance with clause R.6.1 DSTU B V.2.5-29: 2006 Gas supply system. Underground steel gas pipelines and p. 8.9 of DSTU 4219: 2003 Steel main pipelines, which will make it possible to use the freed up personnel in other areas.

Biochars in Iron Ores Sintering Process: Effect on Sinter Quality and Emission

The article presents results of the research on the use of chars produced during pyrolysis of residual biomass as a substitutional fuel in the iron ore sintering process. Such an approach allows to implement circular economy and industrial symbiosis to the iron and steel branches. The effect of the substitution of conventional coke breeze fuel used in sintering on final sinter quality and emission was examined. With regard to productivity, fuel consumption, and properties of the sinter it was shown that the share of tested biochars in fuel may be kept at 10, and up to 30, wt.%, depending on the biochar type. It was observed that with the use of the biochars, the content of iron oxide in the sinter decreased, which was advantageous. Moreover, the sinter obtained in the presence of biochars was characterized with better strength and abrasion than the sinter obtained with coke breeze-based fuel, improving the final product quality. The presence of biochar influenced the raw exhaust gas composition and resulted in a slight increase of organic and inorganic carbon compounds content, while the amount of sulfur oxides was noticeably decreased. It was concluded that the biochars may be applied in the sintering process at established share in the fuel stream.

Partial substitution of anthracite for coke breeze in iron ore sintering

In the sintering of iron ores, the partial substitution of anthracite for coke breeze has been considered to be an effective way of reducing pollutant emissions and production cost. In this study, the basic characteristics of anthracite and coke breeze were compared and the sintering performance at different substitution ratios of anthracite for coke breeze was investigated. The porosity of anthracite is lower than that of coke breeze, but its density and combustion reactivity are higher. The substitution of anthracite for coke breeze has no influence on the granulation effect of the sintering blend. As the anthracite proportion increased, the sintering speed and productivity increased and the sintering yield and tumbler index decreased. As the substitution ratio increased from 0 to 60%, the melting temperature duration and the melt quantity index decreased from 2.59 to 2.03 min and from 3218.28 to 2405.75 °C·min, respectively, leading to insufficient sintering mineralization and bad sintering indexes. For an anthracite substitution ratio of 40%, the sintering speed, sintering productivity, sintering yield and tumbler index were 22.34 mm min−1, 1.49 t·(m2 h)−1, 71.65% and 63.59%, respectively, which entirely satisfies the production requirements. Furthermore, hematite (Fe2O3), calcium ferrite (CaO–Fe2O3), and compound calcium ferrite (CaO–SiO2–Fe2O3) were the major mineral phases, which were embedded with an interwoven structure.