Lignite oxidative desulphurization Notice 1.Process condition selection

The process of lignite desulphurization via its treatment by an oxidant(air or air–steam mixture)has been studied.The research objective was useful determination of steam application in oxidative lignite desulphurization.It has been proved that the water steam should be included in the oxidant composition to increase the hydrogen sulphide and combustible constituent content in the gases obtained during the processes under research.The impact of factors which affect the reactions between solid(in our case–lignite)and gaseous reagent(oxidant,i.e.air and or air–steam mixture)upon the research process has been investigated,if these reactions occur in the kinetic area.Such factors are linear rate of oxidant movement and coal grain size.The values of oxidant movement linear rate and coal grain size,which the reaction transfer from pyrite sulphur and organic content of lignite from diffusion into kinetic area occurs by,have been determined.Under these‘‘transfer’’conditions,the values of coefficients of oxidant mass transfer(β,m/s)as well as Sherwood criteria and boiling layer differences have been calculated.

Study of oxidative desulphurization process of coal with different metamorphism degrees

The oxidative desulphurization process of coal with different metamorphism degrees treated by an air-steam mixture has been studied.It has been shown that the pyrite present in black coal and anthracite is oxidized with the sulphur dioxide formation,and the process chemical mechanism does not depend on the quality of organic matter.The medium-metamorphized coal,capable of turning into a plastic state and cake in the range of investigated temperatures(350～450 ℃),is desulphurized with the greatest difficulty.The chemical mechanism dealing with the transformations of pyritic sulphur present in brown coal differs from similar processes taking place in black coal and anthracite,because FeS2 is converted with hydrogen sulphide formation at desulphurization.

Lignite oxidative desulphurization. Notice 2： effects of process parameters

The influence of main characteristics upon conversion directions of the lignite organic part during its oxidation desulphurization was studied. The optimum temperature values, the ratio oxidant ： raw material, and time of coal stay in the reaction zone, which provide the maximum degree of sulphur conversion and hydrogen sulphide content in desulphur- ization gases, were calculated. The process implemented under these conditions will decrease environment pollution by sulphur dioxide during further lignite burning at least to 55 %-60 % and utilize sulphur in coal in the form of desul- phurization gases with hydrogen sulphide content of 7 %. Such obtaining sulphur. The effect of the above three factors on the depth was studied. gases can be reprocessed by the known methods of and character of the coal organic matter transformation

Effect of hydrodynamic desulphurisation of low parameters on the oxidative rank coal

In this paper, the desulphurisation of high sulphur low-rank coal is proposed as a raw material for pulverised coal injection technology. Therefore, the influence of oxidant linear velocity and the size of the coal grain was investigated in a fluidised bed. The hydrodynamic parameters of the fluidised bed including： porosity, Sherwood criterion （diffusion Nusselt number）, and mass transfer coefficient （external surface） were calculated. Furthermore, the study examined the effects of intensity and efficiency on the desulphurised coal properties; organic matter, ash, and volatile matter contents. The key changes during the conversion of pyritic sulphur and coal organic matter were subsequently examined. The results showed that the sulphur content （St^d 3.16 wt%） of the low-rank coal, was transformed to （St^d 〈 1.5 wt%） after desulfurization. Other enhanced properties were： V^daf ≤ 38.0 wt%; A^d 〈 10.0 wt%, now suitable for pulverised coal injection technology.

Mesopore-encaged V-Mn oxides:Progressive insertion approach triggering reconstructed active sites to enhance catalytic oxidative desulfuration

The oxidative desulphurization(ODS)has become mainly popular by rapid catalytic oxidation of dibenzothiophene(DBT)relied on efficient heterogeneous catalyst,V-based catalytic active species were regarded as the potential option in the activity-preferred ODS systems.Herein,we reported the redispersion of vanadium oxide(VO_(χ))on the mesoporous silica modified with manganese oxide(Mn_(3)O_(4)) through one progressive insertion approach of metal oxides in the silica.Impressively,mesoporeencaged vanadium-manganese oxides in the silica(VMn-MS)as the admirable output of excellent ODS catalyst was demonstrated compared to other monometal-modified counterparts and one-pot implanted one.The characterization results revealed the post-implanted VO_(χ) species not only deposited around the pre-covered Mn_(3)O_(4) on the mesoporous surface but also inserted the surface layer of Mn_(3)O_(4) inducing the amorphous evolution of aggregated Mn_(3)O_(4) and the reconstruction of final active sites.This integrated approach made the reconstructed active species afford more exposed catalytic sites and the tailored surface redox cycles owing to the electronic communication of V-Mn.The catalytic results demonstrated the excellent catalytic desulphurization efficiency(~100%)during 60 min at 80℃,which made the sulphur content reduce to 6 mg·L^(-1),remarkably superior to other comparative samples.The outstanding catalytic performance of VMn-MS catalyst can be ascribed to the synergistic effect of V-Mn dual metals rendering two different reaction pathways,which includes free-radical reaction and ring-forming reaction,where Mn site acted as active center triggering reactive free radicals which could be further optimized by surrounded V sites around Mn sites to promote the ODS process.