Relevance of the composition of municipal plastic wastes for metallurgical coke production

This study is concerned with the effects of the composition of mixed plastic wastes on the thermoplastic properties of coal, the generation of coking pressure and the quality of the resulting cokes in a movable wall oven at semipilot scale. The mixed plastic wastes were selected to cover a wide spectrum in the relative proportions of high- and low-density polyethylenes (HDPE and LDPE), polypropylene (PP), polystyrene (PS) and polyethylene terephthalate (PET). From the results it was deduced that the reduction in Gieseler fluidity in the coal blend is linked to the total amount of polyolefins in the waste. It was also found that these thermoplastics increase the pressure exerted against the wall in the course of the coking process and that coke quality is maintained or even improved. However, when the level of aromatic polymers such PS and PET are increased at the expense of polyolefins, the coking pressure decreases. Thus, the amount of aromatic polymers such as PS and PET in the waste is critical, not only for controlling Gieseler fluidity and coking pressure, but also for avoiding deterioration in coke quality (reactivity towards CO CRI and mechanical strength of the partially-gasified coke CSR). An amount of polyolefins in the waste lower than 65 wt.% for a secure coking pressure is established

Biomass derived products as modifiers of the rheological properties of coking coals

En: 1st Spanish National Conference on Advances in Materials Recycling and Eco – Energy Madrid, 12-13 November 2009.-- Editors: F. A. López, F. Puertas, F. J. Alguacil and A. GuerreroThe modifications in the development of fluidity of a coking coal caused by eucalyptus wood and its carbonization products (charcoal and tars) were assessed by Gieseler plastometry. In addition, three biomass model compounds (cellulose, xylan and lignin) were selected for comparison with biomass products. Thermogravimetry was used to follow the pyrolysis behaviour of the biomass products and model compounds and to study the role of them in the reduction of coal fluidity.Peer reviewe

Relationships among coking coals and related cokes characteristics: a statistical evaluation

From 61 coking coals, 36 coal blends were prepared. Using a pilot coke oven, cokes were prepared from both 61 coking coals (Type I cokes) and 36 coal blends (Type II cokes). Coals were characterized by 14 coal characteristics and cokes by Coke Reactivity Index CRI and Coke Strength after Reaction with CO2 CSR. For the study of mutual statistic relationships among experimentally determined characteristics of coals and cokes, the Factor (FA) and Regression Analyses (RA) were used. FA distributed characteristics of coals and Type I cokes into 4 factors while characteristics of coal blends and Type II cokes were distributed into 7 factors. In case of pure coals and Type I cokes, strong relationships with high correlation coefficients (R > vertical bar 0.60 vertical bar) were more abundant than in case of coal blends and Type II cokes. FA was used for the selection of coal characteristics that influence the coke quality the most significantly. These characteristics were then recalculated by RA for the predictions of CRI/CSR of Type I cokes. Predictions of CRI/CSR of Type II cokes were calculated from coal blends by the same procedure. The comparison of the predicted and experimentally determined CRI and CSR indexes showed much more reliable prediction of CRI/CSR indexes calculated from coals than calculated from coal blends. This study also explains the dominant reasons of this observation.Web of Science15332231

Coal pump development phase 3

Techniques for achieving continuous coal sprays were studied. Coazial injection with gas and pressure atomization were studied. Coal particles, upon cooling, were found to be porous and fragile. Reactivity tests on the extruded coal showed overall conversion to gases and liquids unchanged from that of the raw coal. The potentials for applications of the coal pump to eight coal conversion processes were examined

Plastometric method in the identification of coal from new and old deposits

The plastometric method provides useful information regarding the suitability of Russian coking coal for the production of metallurgical coke. The discrepancies between test results in different laboratories are explained. The case is made for trainings in plastometry at laboratories of coke plants and their suppliers. © 2013 Allerton Press, Inc

Importance of biomass and binder selection for coking briquette preparation: their effect on coal thermoplastic properties.

Blends consisting of a high volatile bituminous coal, biomass and binder that were used in the preparation of briquettes were analyzed in order to select the best components from the viewpoint of their influence on the coal’s thermoplastic properties. The raw materials were studied by means of thermogravimetry, high-temperature rheometry, high temperature proton nuclear magnetic resonance (1H NMR) and Fourier transform infrared (FTIR) spectroscopy. In addition, the fluidity of the blends was determined with the standard Gieseler plastometer test method (ASTM D 2639-74). Various parameters derived from these different techniques were used to explain the effects of biomass and binder on the fluidity of the blends with coal. It was found that the deleterious effect of biomass was mainly related to its physical properties, whereas the effect of the binder was controlled by its chemical composition. Coal tar, coal tar sludge, pine sawdust and a bio-coal derived from hydrothermally treated waste biomass obtained from pruning were the best materials for the preparation of briquettes for cokemaking