STUDIES ON NUCLEAR COAL GASIFICATION IN ARGENTINA

NASSINI D.; FOUGA G. G.; DE MICCO G.; NASSINI H.; A.E. BOHÉ

Budapest

Encuentro; Technical Meeting on Operating Experience with, and Project Feasibility of, Process Heat Applications; 2016

IAEA

Coal gasification technologiesoffer the potential ofa cleaner and more efficient energy than conventionalcombustion processes. Nuclearcoal gasification is a process that uses nuclearenergy for providing indirectheating to the gasification reactors, in order toreplace the partialcombustion of the feed material that is needed to drive theendothermicgasification reactions, contributing then to the saving of fossilfuelresources and lowering the specific carbon emissions to the environment.Argentina is presently exploringthe application ofnuclear coal gasification technologies to domestic solid fuelmaterials such asa low-rank coal extracted from the Río Turbio minefield,asphaltites and petroleumresidues. Since the chemical composition, the heating valueand, then, thefuture use of the synthesis gas produced by the gasificationprocess arestrongly dependent on the solid fuel composition and rank, thegasificationtechnology to be applied should be primarily matched to theproperties of the feedmaterial available for gasification.In this framework, acomprehensive research programis being implemented to characterize thebehaviour of our domestic solid fuels undertypical gasification conditions,with the objective of identifying the mostsuitable gasification process to beimplemented for nuclear hydrogen production.The research program comprises boththeoretical and experimental studies onlaboratory scale which were designed toprovide the necessary information aboutthe fundamental mechanisms and kineticsof gasification reactions, as aprevious step for a further scaling up ofexperimental facilities.In order to simulate properly thegasificationconditions occurring in a large-scale commercial gasifier and,then, achievethe kinetics/mechanism of the gasification, it is essential toreproduce, atleast: (1) the rapid heating of solid fuel particles, and (2) thegasconvection around individual particles with definable intensity.Theexperimental approach followed to achieve both objectives is the so-called two-stagesexperiments in which thegasification reactivities are measured on charsamples prepared in a previouspyrolysis step under inert atmosphere, wheresolid fuel particles are heated ina drop tube furnace at high-heating rates andshort residence times.In this paper, recent results ofstudies ongasification of Argentine solid fuels in presence of steam and CO2asgasifying agents are presented. The kinetics of the CO2gasificationhas been studied by thermogravimetry between 800 and 950ºC and CO2partialpressures from 28 to 82 kPa, using isothermal and non-isothermalmeasurements tostudy the influence on the reaction rates of several parameterssuch as thegaseous flow rate, sample mass, temperature, and CO2partialpressure. The experimental conditions under which the reaction rateiscontrolled by chemical reaction were established for the setup used, andatheoretical model to describe the evolution of the reaction degree asafunction of time was developed.Steam gasification was alsoinvestigated using a specially designedexperimental setup, which is able toproduce different partial pressures ofsteam. Gasification reactions wereproduced in a tubular flow reactor heated byan electrical furnace that canreach temperatures up to 950ºC. The overallreaction rates under differentexperimental conditions of gaseous flow rate andsample mass were determined byfollowing the temporal evolution of the gaseousproduct concentration by gaschromatography.