Clean Production of Coke from Carbonaceous Fines

2007

A series of coking coals covering a wide range of coalification, thermoplastic properties and geographical origin were carbonized at two different scales. All the coals used are available in the international market and they are used by the cokemaking industry in blend preparation. The cokes were produced in two movable wall ovens of 15 and 300 kg capacity available at INCAR-CSIC facilities. The quality of the cokes was assessed by means of reactivity towards carbon dioxide and mechanical strength before and after the reaction with CO2. The results obtained are very promising and a good correlation between the quality parameters of the cokes produced in the two ovens was found. The use of a semi-pilot oven against big-capacity ovens in the optimization of complex coking blends allows to obtain valuable results by using small amount of coal (15 kg vs. 300-400 kg) with the advantages that it is quicker, more flexible and of lower cost.

2015

xiii CHAPTER 1: INTRODUCTION 1 1.1 Background and Motivation 1 1.2. Problem Statement 3 1.3 Hypothesis 3 1.4 Study Objectives 4 1.5 Outline of Research Report 4 1.6. Summary 5 CHAPTER 2: LITERATURE SURVEY 6 2.

This paper deals with a technology for formed coke production. Milestones in the development of this technology are summarized. Then, the equipment and the process are described. The environmental impact is briefly addressed. The products obtained along the processes, including char, gas, liquids and coke are characterized, and possible applications are mentioned. As an example, an economical evaluation of a given project is detailed. Finally, a coke cost exercise is carried out.

KnE Engineering, 2018

The objective of this article is the selection of cokemaking technology within an Iron & Steel Works (I&SW), involving analysis of coal quality, coke demand and supply, environmental regulations, and the plant energy balance. The methodology involves coal blend selection, preparation, charging, cokemaking and quenching technology selection to meet the blast furnaces' coke quality requirements and the I&SW energy balance. Hatch's mass and energy balance, OPEX, CAPEX, Energy/CO 2 and Financial Models provide the client with NPV/IRR ranking and sensitivity analysis to assist in selecting the best strategy amongst by-product or heat recovery ovens, charging and quenching systems for replacement or expansion programs. The developed methodology was successfully applied for development of coal and cokemaking strategy, estimation of required cokemaking capacity for the metallurgical giant, which incorporates four integrated iron and steel works, two stand alone coke plant and several coal and iron ore mines. Some of Hatch's recommendations are already implemented and tested by the client. The optimum selection of cokemaking technologies requires a careful analysis of the I&SW and companyspecific requirements in order to develop a techno-economic analysis that will provide the optimum strategy to get the most from existing assets and to ensure competitive future coke production. Development by Hatch methodology could be successfully applied for selection and construction of green site cokemaking facilities as well as for brown field modernizations.

Energies, 2020

This paper presents the results of studies on the possibility of using lignite to produce blast furnace coke. The aim of the investigation was to evaluate the influence of lignite addition (direct addition or incorporated into briquettes) on the textural, structural and quality parameters (NSC-CRI and CSR) of blast furnace coke. It was found that the introduction of lignite in briquettes (4.5% addition) allows coke to be produced that is characterized by equally high NSC parameters as for coke obtained without lignite addition for standard top-charged operation.

This paper is an update of a previous publication in Spanish [1]. One of the current trends in the production of metallurgical coke is the comeback of non-recovery ovens. This is driven by less interest in byproducts, smaller investment per annual ton, better environmental performance. The development took place particularly in China, India, USA, Brazil, Australia and Colombia [2]. In the USA, one important factor promoting this technology was that EPA declared it as Maximum Achievable Current technology in 1990. This technology arises from the classic beehive ovens which supplied since the XVIII century the coke for the industrial revolution. Those ovens were manually operated, with small heat recovery, just for heating the oven. Now, non-recovery ovens are modern construction, with highly mechanized operation, and automated to a certain degree. Gases generated by the combustion of the volatile matter are sent through downcomers and further burnt to heat the oven bottom and sides; in many cases, mostly when the plant is built within or closed to a steelmaking facility, the hot gas is used for vapor generation and electric power production. Main differences between conventional and non-recovery/heat recovery processes are shown in figure 1. In conventional process, the coal charged receives the heat indirectly through the furnace walls, by combustion of external gas; inside the oven, positive pressure develops. Gas generated in the coking process is sent to the by-products plant. In non-recovery ovens, coking proceeds from the top through direct heating by the partial combustion of the volatile matter over the coal bed, and from the bottom by heat coming from full combustion of gases escaping from the oven. In these plants, the offgas is treated and sent to the stack, in many cases after recovering sensible heat to produce vapor and electric power. Installed capacity for these furnaces was esteemed in 2005 in 22 M metric tons per year, probably including beehive ovens [2]. In table 1, some of the non-recovery coke plants currently operating are listed. Some plants belong to companies with coal mining as its core business; others are independent coke producers, purchasing coal and selling coke; then there is some joint ventures between coke producers and steelmakers, and finally, captive coke plants belonging to steel companies.

Ironmaking & Steelmaking, 2020

© 2020 Institute of Materials, Minerals and Mining. A coke produced using a custom-built sole-heated oven and a coke prepared in a pilot-scale oven from a matched coal, were compared using a range of analytical techniques. The aim of this comparison was to assess to what extent the small-scale soleheated oven can successfully replicate the production of pilot-scale oven cokes, and thus be used to rapidly prepare and screen a wide range of cokes for particular characteristics, e.g. abrasion resistance. The techniques applied included conventional methods and novel methods developed by our research team. These included microstructural and microtextural analyses of samples of each coke, and tribological, scratch test and fractographic analyses, each of which elucidates different strength attributes. These include microstructural weaknesses, abrasion resistance, and the strength of microtextural interfaces. The level of replication achieved indicates that the sole-heated oven, used in combination with an annealing step in a muffle furnace, can be beneficially used to model the pilot-scale oven.

Coke and Chemistry, 2012

A critical review reveals extensive experimental data on the continuous production of nonmetallur gical coke. In view of the large reserves of poorly clinkering coal in Ukraine and the need to produce sufficient coke for consumers outside of the metallurgical industry, the expansion of such research seems expedient.

Revista Ingenieria E Investigacion, 2011

El lavado del carbón en la industria siderúrgica se utiliza para adecuar la calidad del material cuando no cumple con las especificaciones de contenido de cenizas y azufre. En los procesos de beneficio el carbón generalmente se separa y lava en tres corrientes paralelas, diferenciadas por la granulometría en gruesos, finos y ultrafinos. Para la coquización se mezclan los gruesos y los finos (tamaño superior a 0,5 mm) (Zimmerman, 1982) y los ultrafinos (tamaño menor a 0,5 mm) y se almacenan o desechan (Stationary Sources Branch, 1988). Estos ultrafinos de carbón, aunque son de buena calidad, debido a su misma naturaleza y procedencia no pueden utilizarse directamente en coquización porque ocasionan problemas de manejo (Wen, 2000). Sin embargo, por el alto costo del carbón coquizable es necesario buscar alternativas para su aprovechamiento en la fabricación de coque metalúrgico, y el proceso de briquetación es una buena alternativa.

Coke and Chemistry, 2015

The coal blend quality and process control of coke making technologies is an important lever to produce quality coke with optimal cost. Apart from impacting cost, this improves the CO 2 footprint. This is facilitated by proper selection of coke making technologies and coal/coal blend. Each technology has its own advantage and limitation based on its design criteria. Recently, Tata Steel introduced Asia largest single loca tion 1.6 mtpa of heat recovery coke plant for the first time. This paper briefly described the operational phi losophy evolved in heat recovery coke plant to produce desired quality coke at comparatively lower cost through operational excellence. The reduction of imported prime hard coking coal in coal blend up to 30% without affecting coke quality adversly and understanding the operational processes and finally mastering heat recovery coke making technology was also part of this paper.