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.

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.

Lignite oxidative desulphurization: notice 3-process technological aspects and application of products

The study reviews the process of oxidative desulphurization of high-sulphur Ukrainian lignite, which was performed by coal treatment using an air or air-steam mixture. In the process. sulphur-free fuel and tar from the decomposition of coal organic matter was obtained. Hence, the sulphur in the coal was converted inlo hydrogen sulphide. The coal desulphurization process is critical to power generatio n. power generation and technology, and tech no logy field of application. The coal desulphurization process ensures the maximum recovery of the highest content of sulphur and hydrogen sulphide (H2S) in desulphurized gases at minimal energy costs. The process also enhances the maximum decomposition of tar and sulphur recovery (> 50%) during coal power generation. Based on smnniarized field studies, a block schematic diagram coupled with heat and material balances of the process was developed for the calculations. The application of the tech no logy at the first stage of coal combustion in thermal power plants will en able the utilizatio n of over 50% of recovered coal sulphur in the form of concentrated H2S or commercial elemental sulphur. This will, nevertheless, allow for a reduction of sulphur oxide pollution in the environment by at least 53%-56%. It has been suggested that the product of thermal decomposition of coal organic matter (tar) can be used as a componenl of fumace fuel oil or as a plasticizer of petroleum-based road bitumen.