神东煤炭集团退休人员社会化管理工作探索及实践

随着神东煤炭老龄化速度加快退休人员数量增加,如何将退休人员管理服务方式由企业转向社会化管理服务,是神东煤炭近两年国企改革工作的重点。本文回顾了神东煤炭集团退休人员社会化管理工作探索和实践过程,以及期间存在的工作量大、缺失党员资料补齐难、档案接收标准高等问题。按照各地政策,神东煤炭提出了先易后难的移交对策;2020年12月底,基本完成了存量退休人员社会化管理移交工作,包括完成了存量退休人员管理职能、人事档案移交,完成了属地党员组织关系转接。企业、政府及退休人员三方均得到受益。     

龙永煤田早二叠世童子岩组第三段聚煤古地理分析

通过龙永煤田古地理分析表明:童子岩组第三段含煤沉积是在受限制的聚煤凹陷中形成的,成煤作用是复杂和不均一的,含煤岩系形成时的坳陷内部存在构造分异。早二叠世童子岩组早期龙永煤田内为浅海相的沉积环境;中期开始的区域性大海退逐渐形成的滨海、海湾泻湖及近海湖泊、泥炭沼泽等环境,并形成了童子岩组第三段含煤建造;晚期海水由东北向西南退出,古地理环境是由浅海向陆地迁移,从而结束了童子岩组地层的含煤建造,预示东吴运动来临。     

Raw materials for Corex and their influence on furnace performance

Abstract

The scarcity of good quality coking coal for the blast furnace (BF) has made steel makers look for an alternative iron-making process that requires little or no coke. The Corex process has been developed as an alternative to BF iron-making, which uses non-coking coal and a small amount of coke as fuel, and pellet/lump ore as iron-bearing feed. JSW Steel operates two Corex units each of 0?8 Mtpa, commissioned in 1998 and 2001 respectively. Iron oxides and non-coking coals have to meet certain physical, chemical and high temperature properties for stable operation and to attain high performance levels. Experience of the Corex operation with various coals and iron oxides over the years has helped in understanding the influence and sensitivity of raw materials on its performance and develop new raw material specifications. Statistical analysis of plant data showed that the significant parameters affecting fuel rate and production are moisture, volatile matter, char strength after reaction of coal, reduction disintegration index (RDI; %, –6?3 mm) of pellets and slag rate. This helped achieve the most efficient operating parameters, surpass rated capacity and utilise steel plant waste. The present paper brings out the impact of various raw material properties, and the modified specifications of coal and iron oxides for Corex.     

Influence of coal fluidity on coal blend and coke quality

Abstract

The blast furnace coke quality depends on the characteristics of coal blend, precarbonisation techniques adopted such as stamping, vibrocompaction etc., and coking conditions. Of the above, coal blend plays a significant role in the production of quality coke. Furthermore, the quality of the blend depends on the quality of individual coals and their interaction making up the blend. Coal, being a highly heterogeneous material, requires special care for determination of its properties and blending of individual coals for coke making. Coal fluidity is one such important coking property which highly influences the coke quality. The hard coking coals having good fluidity, which yield good coke, however are not only very expensive, but also are limited in reserves. Unlike, other properties, coal loses its fluidity on weathering, i.e. oxidation in presence of air on long storage in the yard, and the fluidity value changes on blending with different coals. To understand the effect of coal fluidity on coal blending and there by the coke quality, studies have been conducted using the industrial scale coals and coal blends. An empirical relation has been developed between actual blend fluidity and calculated fluidity using logarithmic weighted average from fluidity of individual coals. Blending of non-coking coals above 20% with the hard coking coals used in this research decreases the blend fluidity and impairs the coke quality. It was seen that the coals lose their fluidity on weathering, and the value becomes less than half after a two months of storage at site. Weathering appears to be more rapid in case of semisoft than hard coking coals. The present paper discusses the influence of coal fluidity on coal blend fluidity and changes on weathering.     

Direct reduced iron production using cold bonded carbon bearing pellets Part 1 – Laboratory metallisation

Abstract

A new cold bonding technology for producing coal bearing composite pellets was developed. Alumina cement was used as binder, which gave high mechanical strength to the pellet even at elevated temperatures. Laboratory test results showed that the metallisation rate of the pellets was high owing to the intimate contact of the particulates of coal and the iron ore in the pellet. The developed cold bonding method can also be used to recycle electric arc furnace (EAF) dust, from which valuable zinc and lead can also be recovered.     

Behaviour of coal ashes for pulverised coal injection at high temperatures in relation to their chemical and mineralogical composition – experimental and computational analysis

Abstract

The selection of coals for pulverised coal injection usually consists of evaluating the carbonaceous matter. However, the reduction of permeability in the lower section of the blast furnace with high rates of pulverised coal injection can be associated with remaining ashes from the coal combustion process. The aim of this work is to evaluate the behaviour of coal ashes at high temperatures in relation to their chemical and mineralogical composition. These ashes were submitted to the following analysis: chemical (X-ray fluorescence), mineralogical (X-ray diffraction), fusibility (heating microscopy) and viscosity (rotational viscometer). The software FactSage was also used to evaluate the behaviour of coal ashes. It was observed that samples present different chemical and mineralogical compositions, reflecting in the fusibility and viscosity of ashes. Their proportions and relevant phases were determined by computational thermodynamics and also related to the experimental work.     

Lessons from the past: materials-related issues in the ultrasupercritical boiler,Eddystone Unit 1

Abstract

Major research efforts in both the USA and Europe have made substantial progress toward the development of coal fired ultrasupercritical steam generators that will operate at efficiencies approaching 50% based on higher heating value (HHV). A test facility designed to evaluate operation of major steam generator components at 700°C is now operational in Germany. A focus of these efforts has been the demonstration of reliability of the materials that would be used in an ultrasupercritical steam generator. However, proof of the viability of ultrasupercritical technology can be found at the Eddystone plant in Pennsylvania. The steam generator for unit 1 at that plant has operated successfully for >45 years in steam conditions more advanced than any other central station unit in operation today. The operating history is briefly reviewed, focusing on the materials related problems that forced a modest retreat from the original, unprecedented design conditions, but emphasising the record of many years of reliable operation. Some significant materials related issues involved in operating a steam generator at 'Eddystone' like conditions are used as a basis to argue that there exists today the materials and manufacturing understanding necessary to construct a more advanced ultrasupercritical unit that will operate efficiently and reliably.     

Determination of the attachment and detachment forces in a coal grain/liquid/coal grain system by detachment experiments

On the basis of measurements of the destruction time of a coal sediment column structure, which were described earlier, a further and more detailed analysis of the results of these measurements was carried out. The radius of the contact plane between coal particles in the studied liquids was calculated. The values of the radius decreased with increasing length of the hydrocarbon chain of both alkanes and alcohols. Next, the values of the attachment force of two coal particles through a liquid were calculated and they increased with increasing length of the hydrocarbon chain of both liquids. We have found a linear relationship between reciprocal of the destruction time and the difference in the detachment and attachment forces. From this relationship we concluded that the work of adhesion of the liquid to the coal surface also influenced the attachment force between coal particles through the liquid.     

Influence of reduction temperature on prereduction of iron oxide with coal carbonisation gas without tar

Abstract

The fundamental study on prereduction of iron oxide was carried out in order to investigate the conditions for efficient use of the volatile matter in coal in an iron bath smelting reduction total process. At a rate of 200 K h^?1 under rising temperature conditions up to 1273 K, 1 kg of non-coking coal having 37 mass-% volatile matter was carbonised. Subsequently, this gas without tar reduced 2 kg of iron oxide pellets packed in a separate reactor at various temperatures between 673 and 1273 K. The fractional reduction F increased linearly from 0·07 to 0·25 at the reduction temperatures up to 1073 K, beyond which F increased more than the linear relation, such as F=0·35 at 1173 K and 0·43 at 1273 K. This may be due to the contribution of hydrocarbons to the reduction reaction at high temperatures. The hydrogen reduction accounts for about half of the fractional reduction. The mass of filtered tar occupied a mass of about half of the volatile matter released during coal carbonisation. This implies that more fractional reduction can be obtained when the tar is used in the process.     

DRI production using cold bonded carbon bearing pellets Part 2 – Rotary kiln process modelling

Abstract

A new cold bonding technology for producing coal bearing composite pellet was developed. Laboratory tests showed that the cold bonded pellet has enhanced mechanical strength, from which good quality DRI can be produced. Based on the laboratory test results, a rotary kiln process was designed for producing DRI. Because of the high metallisation rate of the pellets and the corresponding novel operation conditions, the proposed rotary kiln process has significantly higher energy efficiency than the SL/RN process, hence emitting less CO₂.