Abstract: High-temperature thermal extraction (TE) of Xianfeng lignite by different solvents was carried out, and FT-IR spectra of extracts and residues were determined. The results indicate that Xianfeng lignite shows the macro-molecular network structure by chemical bond cross-linking, in which some low molecular compounds are associated by non-covalent interaction. The TE can distinctly increase the extraction yields, which are up to 20.7% and 21.3% at 300℃ in toluene and tetralin, respectively. The extracts result from the release of low molecular compounds by thermal rupture of non-covalent bonds at high temperature. Meanwhile, there is no obviously pyrolysis in the process of thermal extraction at 300℃. So the hydrogen donor solvent and hydrogen bond solvent can not increase the thermal extraction yield. The thermal extracts of Xianfeng lignite contain a great of aliphatic alkyl and carbonyl ester, a little of hydroxyl and aromatic structure. The solvent of thermal extraction shows distinctly influences on the constitution and structure of extracts.
Abstract: The ash fusibility temperature (AFT) and slag fluidity of three different coal ash samples through addition of CaO with different amounts were studied. Especially the variation of temperature at critical viscosity was examined at different viscosities. The results show that the fusibility temperatures of coal ashes decrease and then increase with increasing addition amount of CaO, which is consistent with the change of liquids temperature with CaO content calculated by FACTsage. Slag viscosity also decreases with increasing amount of CaO addition above the temperature of critical viscosity (Tcv). The temperature of critical viscosity firstly decreases with increasing addition of CaO, and then reaches a minimum value when the content of CaO is around 15%. FCATsage was employed to calculate the liquid composition at the temperature of critical viscosity. It indicates that high content of FeO of liquid leads to the low temperature of critical viscosity.
Abstract: The Mayer bond orders of 4 typical pyridinic-nitrogen structures in coal and their intermediate products were calculated with considering the combination forms of pyridine cycle with other heterocycles. On the basis of the Mayer bond orders, the bonds apt to crack during pyrolysis were deduced and the mechanisms for the release of nitrogen during pyridinic-N pyrolysis were analyzed. The result showed that pyridinc-N tends to release as HCN during pyrolysis. The diversity of the combination forms of pyridine cycles with other cycles can also lead to a variety of nitrogen release processes. Rapid pyrolysis of pyridine and acridine as pyridinic-N model compounds was conducted experimentally in a high frequency furnace; it suggested that a small quantity of NH3 is formed during pyridine and acridine pyrolysis, but HCN is the dominant nitrogen containing product. Current experimental results provide some evidences to support the calculation results.
Abstract: Three coals were combusted in a drop tube furnace. An Andersen particle sizing impactor was employed to separate and collect the ash particulate matter (PM) after coal combustion. Mercury injection apparatus, SEM-EDX, ICP-AES were taken to detect the tested coals and graded ash PM. The effect of coal physicochemical properties on ash particle size distribution (PSD), appearance, constituents and enrichment of trace elements of PM was examined. The results show that the pore structure of coals, occurrence characteristics and concentration of constituents influence the behavior of ash fragmentation and the transition procedure of constituents, forming different morphological and inequable PM, and leading to the different PSD. Simultaneously, they will influence the vaporization and coagulation of elements as well as the redistribution in the graded PM.
Abstract: The pyrolysis of cellulose to produce levoglucosenone (LGO) with solid superacids (SO42-/TiO2 and SO42-/ZrO2) as catalyst was investigated by Py-GC/MS. Non-catalytic pyrolysis of pure cellulose was firstly carried out to reveal the effects of pyrolysis temperature and time on the formation of LGO. Then the mechanic mixture of cellulose with an equivalent mass of the superacids (SO42-/TiO2 or SO42-/ZrO2) was subjected to fast pyrolysis to investigate their catalytic effect on the pyrolytic products. The results indicated that during the fast pyrolysis of pure cellulose, the LGO is mainly formed at low or medium temperatures through a combination of dehydration and depolymerization reactions. The superacids as catalyst can significantly promote the formation of LGO; the relative content of LGO in the product exceeds 60%.
Abstract: The fir char gasification with CO2 and H2O were investigated with a fixed-bed apparatus, and the pore structure characteristics and the CO2 gasification reactivity of the partially gasified char were examined. The results of pore structure analysis indicate that during gasification the pore properties are affected by gasification agent, which means that during CO2 gasification mainly micropores are produced and the pore diameter is mainly in the range of 0.4nm~0.9nm, while during H2O gasification the micropores are produced at the beginning and then the mesopores are developed. The correlation between CO2 gasification reactivity and BET surface area shows that the char reactivity is affected not only by BET surface area but also by pore properties.
Abstract: The gasification experiments of co-gasification of biomass and petroleum coke were conducted in a fixed-bed reactor to determine the effect of the gasification mode, mix mode and proportion, particle size of petroleum coke on the tar yield and gas heat value, which was intended to provide the support for the idea of decoupled dual fluidized bed co-gasification of biomass and petroleum coke. The results show that the gas heat value decreases from 5.35MJ/m3 to 2.98MJ/m3 with the increasing of oxygen content from 2% to 15%. The average tar yield is 6.4%, and gas heat value is 4.31MJ/m3 as biomass is gasified alone at 700℃. For the co-gasification, the average tar yield is 2.9%, and gas heat value is 5.19MJ/m3. At the temperature of 700℃, the best ratio of the petroleum coke to biomass is 1∶1 as the oxygen content is 4%. The largest tar yield is produced for the gasification with petroleum coke alone, and the smallest tar yield for the co-gasification with feeding the petroleum coke first. With the increasing particle size of petroleum coke, the tar decomposition rate decreases gradually. The tar yield decreases with temperature for any case.
Abstract: To investigate the variation of pore structure characteristic during calcium-enriched bio-oil calcination process, the thermal decomposition of calcium-enriched bio-oil (CEB) was tested in a thermogravimetric balance. The results show that there are three reaction stages: the formation of CO2 and H2O, the decomposition of organic carboxylic acid calcium salt, and the decomposition of calcium carbonate. The calcium oxide particles obtained from decomposition and calcination of CEB were analyzed to determine the physicochemical characteristics. It can be noted from the pore structure parameters that the decomposition of organic carboxylic acid calcium salt has important influences on the pore structure of product. The cavitation by gas release and the carbonization deposition of macromolecular compound coexist in the temperature range of 450℃~600℃, but the latter is dominated. The carbonization deposition of macromolecular compound mainly occurs in the range of 500℃~600℃. After 600℃, with the decomposition of calcium carbonate and the release of carbon dioxide, new micropores are formed in calcined product. Under the same calcination temperature, the pore characteristic of CEB calcined product is obviously superior to that of calcium carbonate.
Abstract: Nano-HZSM-5 was modified by different alkali metal ions; the effect of the modification on its acidity and catalytic performance in butene cracking was investigated by using NH3-TPD characterization and catalytic evaluation in a small fixed-bed reactor. The results indicated that although the catalysts modified with various ions of Li, Na and K are different in their metal loading required to achieve the highest selectivity to ethylene and propylene, the best selectivity value obtained over all these modified catalysts is located in 50%~60%. The activity of the alkali modified catalysts decreases slowly with the extension of the reaction time on stream; however, the selectivity to ethylene and propylene does not increase accordingly. The conversions of different butene isomers over the zeolite catalysts are decreased in the sequence of butene-1 > trans-butene-2 > cis-butene-2 > iso-butene, which may reflect the order of their reactivity towards cracking.
Abstract: The selective catalytic reduction (SCR) of NO by CH4 in the presence of SO2 was investigated over the catalyst cobalt supported on Mordenite (Co/MOR); both the fresh and spent catalysts were characterized by temperature-programmed desorption of NO (NO-TPD), X-ray diffraction (XRD), H2 temperature-programmed reduction (H2-TPR), and UV-vis diffuse reflectance spectroscopy (UV-vis DRS). The results indicated that the presence of SO2 in the feed leads to a decrease of NO conversion at a temperature below 550℃; however, this influence is not evident at a temperature above 600℃. Moreover, the negative effect of SO2 on the NO conversion is reversible over the Co/MOR catalyst. SO2 may inhibit the adsorption of NO on the active sites and promote the formation of CoO during the reaction, which leads to a decrease of the active sites and the activity of Co/MOR for the SCR of NO.
Abstract: The influences of co-existing components including O2, CO2 and H2O in flue gas on simultaneous desulfurization and denitrification using microwave irradiation over activated carbon are mainly studied in this paper. The results show that SO2 inhibits the denitrification reaction on some extent. The water vapor in the flue gas has some inhibitory effect on desulfurization while accelerates the denitrification reaction. But once the moisture content is more than 9.0%, both the efficiencies of desulfurization and denitrification will decrease. The presences of O2 and CO2 can enhance the efficiencies of desulfurization and denitrification. But high concentrations of O2 and CO2 will cause the loss of activated carbon, thereby inhibit desulfurization and denitrization. Furthermore, the efficiency of removing SO2 and NOx using this technique is higher than 90% and the reaction products are friendly to the environment. The results have a great value for the process optimization of simultaneous desulfurization and denitrification using microwave irradiation over activated carbon.
Abstract: The denitrification behaviors of fresh and used honeycomb SCR catalysts were compared and the deactivation reasons were analyzed by using Fourier transformation infrared spectra (FT-IR), N2 adsorption/desorption, X-ray diffraction (XRD), and scanning electron microscope (SEM). The results show that the functional groups on the surface of the used catalyst are changed and the specific surface area of the used catalyst decreases seriously. Moreover the TiO2 crystallite of used catalyst is changed and some nano-particles aggregate on the surface of the used catalyst. The reason of the deactivation of use catalyst is the unexpected high temperature (e.g. t> 650℃). Otherwise, the water soluble ions, arsenic and phosphorus in the deposit on the surface of the used catalyst can also affect the catalytic activity.
Abstract: The release behavior of Hg captured on V2O5/AC during regeneration and temperature programmed desorption (TPD) processes was studied. The Hg0 capture capability of the regenerated V2O5/AC was also tested. It was found that 81% or 94% of Hg captured on V2O5/AC can be released during the thermal (Ar, 400℃) or NH3 (NH3/Ar, 300℃) regeneration processes. The released Hg is mainly in the form of Hg0 due to the reduction activity of carbon in AC. The TPD-AFS profile reveals that the release behavior of Hg under Ar and NH3/Ar atmospheres is different. NH3 in the atmosphere improved the release of Hg by lowering the highest release temperature to 300℃. Under pure Ar atmosphere the release of Hg still can be observed above 400℃. It caused the difference in Hg release ratio respect with the two regeneration processes tested. However, when NH3 concentration increases from 1% to 5% or higher the Hg release ratio is unchanged. If the higher regeneration temperature was used the difference in Hg release ratio during the two regeneration processes should vanish. Regeneration methods have slight effects on Hg0 capture capability on V2O5/AC. The Hg0 capture capability of regenerated V2O5/AC under the two processes is similar, which is lower than that of the fresh V2O5/AC but still much higher than that of AC.
Abstract: Hydrogen production performance of a membrane-less bio-electrochemically assisted microbial reactor was studied in this paper. Membrane-less microbial reactor consisted of carbon felt as anode, carbon plate supported by self-made Ni-Al-Sn alloy powders(Ni-50%,Al-45%,Sn-5%) as cathode and acetate as electrolyte for generating hydrogen. Its principle was that the organic was degraded by microbe to produce electron and protons in the anode chamber, and then protons arriving at cathode got electron and generated hydrogen through an applied voltage between two electrodes of membrane-less microbial reactor. The influences of carbon felt amount used for the anode, environment temperature, and applied voltage, etc. on hydrogen production rate and hydrogen selectivity were studied. And the optimal results demonstrated that the rate of hydrogen production reached at 4.21m3/(d·m3) and the highest hydrogen selectivity was 70.4% when the anode surface area was 900cm2, the environment temperature was 30℃ and the applied voltage was 0.9V.
Supervisor：Chinese Academy of Sciences
Sponsors by：Shanxi Institute of Coal Chemistry, Chinese Academy of Sciences Chinese Chemical Society
