Prof.Dr. Chunhu Li and his group are dedicated majorly in the fields of FCC Gasolineand Diesel desulfurization as well as Flue Gas desulfurization, Sea water FlueGas desulfurization.

1.Removal of sulfur from fuel

Sulfurremoval from transportation fuels has become a very important and activeresearch subject worldwide in the last 10 years. The desulfurization of dieselfuels is of great significance because the sulfur content in crude petroleum isincreasing while regulation limit of commercial diesel fuel decreasesgradually. In Beijing Euro-3 emissions standard has been followed from 1st July2005, which means that the sulfur content has to be reduced to below 150µg/gand 350µg/g for gasoline and diesel oil respectively. Hydrodesulfurization, aconventional approach used for desulfurization of fuel oil in refining plant,requires rigor operating condition. Therefore, development of newdesulfurization approach becomes more and more stringent. Adsorptive andOxidation-extraction Removal appear to be two kinds of new promisingdesulfurization processes.

InProfessor Li’s research, carbon based adsorbents were used in the adsorptiveremoval in fuel oil. Both activated carbon and activated semi-coke can be usedas adsorbent or adsorbent support. It was shown that carbon based adsorbentsprepared can effectively remove sulfur, especially adsorb sulfur species thatbe removed difficultly during hydrodesulfurization in fuel oil. Removalefficiency can be improved by impregnating transition metal or modifying thesurface and structural properties of carbon materials using acid pretreatmentor hydrothermal process. The effects of preparation parameters anddesulfurization condition of adsorbents on sulfur removal performances of fueloil were intensively investigated in order to obtain optimal condition. Thecost of desulfurization for fuel oil was greatly decreased because ofutilization of cheap semi-coke. In the meantime, effective regeneration methodswere developed in order to increase accumulated sulfur capacity of adsorbents.

Inoxidation-extraction process, solid or emulsion catalysts were used whilehydrogen peroxide or oxygen was as oxidant. The sulfur removal efficiency forgasoline can over 40% at room temperature.

2.Removal of sulfur from flow gas

InChina,coal is one of primary energy sources. The combustion of coal has led to severeair pollution due to the emission of SO₂. The worldwide trend towardincreasingly stringent emission standard has spurred significant research oncost-effective technologies for reducing SO₂ emission. On the otherhand, sulfur resource is relatively insufficient in China. Therefore study on flue gasdesulfurization (FGD) with sulfur recycling has great significance.

Thesemi-coke is the most promising carbon-based desulfurizer for the flue gasdesulfurization (FGD) owing to its low cost and high sulfur capacity.Semi-cokes obtained from different coal such as bituminous coal, anthracite andlignite were investigated. Desulfurizing activity of raw semi-coke can bemodified using hydrothermal process, HNO₃ oxidation and heattreatment at high temperature. Activated semi-coke was regenerated by usingammonia solution or water scrubbing. The results indicated that activated semi-cokemodified by a series of chemical treatments has excellent desulfurizingability, SO₂ removal activity of the activatecd semi-coke adsorbentafter 10 cycles of desulfurization and regeneration is not obviously reducedand its total sulfur removal capacity has reached 400%(g sulfur/g adsorbent).When concentration of SO₂ was between 1000 and 5000ppm, the removalefficiency was more than 90%.

3.Hot Gas Desulfurization (H2S) at High Temperature

Coalis the most abundant fossil energy in the world.  Integrated gasification combined cycle (IGCC)power generation process is as an attractive option for using coal forelectricity generation with a high efficiency and a low environmentalpollution, and is regarded to be the most promising technology in this century.In IGCC system, removal of sulfur species (mainly H2S) is crucial for theefficient and economic coal utilization. Up to now, the main problem of hightemperature coal gas desulfurization technology is the decrease of durabilityof desulfurization sorbents, which was considered to be an obstacle forindustrial development. In order to solve the problems, it is very necessary tomaster the behaviors of desulfurization of the sorbents, the rules of texturechanging in simulated coal gas during cycles, and the effects of additives onthe performance of desulfurizer.

Inthis Lab, various clay were chosen as the additives of iron oxide sorbent madefrom iron steel plant redmud and zinc oxide. Texaco coal-derived gas wasutilized for evaluation of the sorbents. It was shown that fixed-bed could bedivided into sulfidation, transmitted and reduction zones which converted toeach other with the process of desulfurization. The results showed that thesorbents, we made, exhibited a high reactivity and sulfur capacity stability.

4.NO removal by photocatalysis

ProfessorLi’s group is dedicated on preparation of a novel semi-coke based denitrifierand applying it in photocatalytic removal of NO. The semi-coke based materialis obtained from different coal such as bituminous coal, anthracite and ligniteand shapes up as grain.  Tetrabutyltitanate, alcohol and semicoke are used to prepare photocatalyst. Semi-coke isfirst activated and supports it with TiO₂ or other transition metaloxides, then activates the system with high temperature treatment andmechanical mixing with ZSM-5. Semi-coke is a promising material because of itslow price and easily obtainable. Photocatalysis and ZSM-5 are effectivelyassisting the removal of NO.