Abstract: Two coals from different coal mines, Liuzhi (LZ) and Zunyi (ZY) in the Guizhou province, with high mercury (Hg) and sulfur (S) contents were studied in this article. Different methods were used to identify the occurrence and correlation of Hg and S in the two coals, such as, float-sink test, sequential leaching test, low temperature ashing (LTA), and also X-ray diffraction (XRD). The results show that the sulfur forms are different in the two coals. Sulfur in the LZ coal is mainly in the pyritic form and in the ZY coal, in the organic form. Mercury is mainly associated with pyrite for LZ coal and with clay minerals for ZY coal. In LZ coal, mercury and sulfur have a good correlation, but in ZY coal the correlation between mercury and sulfur is not so good.
Abstract: The transformation and releasing characteristics of sodium during steam gasification of the chars from rapid pyrolysis of lignite with addition of different concentrations of NaCl and NaAc have been studied in a fixed bed at 900 ℃ and 950 ℃ under atmospheric pressure. The results show that part of watersoluble sodium and acidinsoluble sodium are transformed into water insoluble but acid soluble during gasification when the concentration of sodium in char is lower. And almost all the sodium is released to gas phase when the addition of sodium is higher. The transformation characteristics of additive NaAc is different from NaCl. Nearly, all the sodium is released to gas phase during gasification. The gasification temperature and the sodium concentration show little influence on the volatility behavior.
Abstract: The catalytic effects of different catalysts, i.e., 3% Ca, 5%Na-BL, and 3% Ca+5% Na-BL catalyst, on carbon conversion, gasification reaction rate constant, activation energy, and relative amount of harmful sulfur containing gases, were investigated by thermogravimetry in steam gasification under temperature 700℃ to 900℃ at ambient pressure for two Pakistani Lakhra (LKH) and Thar (THR) lignite chars. High carbon conversion can be obtained by direct gasification of both LKH and THR chars, but the gasification rate became much fast using BL catalyst. THR char with high ash content was easy to form some complex silicates during BL catalytic gasification, leading to a lower conversion than that of LKH char with low ash content. SO2 and H2S as sulfurcontaining gases produced by char and BL itself in steam gasification can be captured by the existence of Ca mixed with BL, which is more effective at temperatures less than 900℃. The shrinking core model (SCM) can be considered as a better choice to correlate the relations between conversion and time and to estimate the reaction rate constant (k) under different temperatures. The reaction activation energy (Ea) and preexponential factor (A) were predicted based on Arrhenius equation. The reaction activation energy of 44.7kJ/mol and 59.6kJ/mol for LKH chars with BL+Ca and BL catalysts were much lower than 114.6kJ/mol and 100.8kJ/mol for THR chars with the same catalysts, respectively. They were also lower than 161.2kJ/mol for LKH char and 124.8kJ/mol for THR char without catalyst.
Abstract: Rapid pyrolysis of two Chinese coals (Binxian bitumite and Jincheng anthracite) and one Ethiopian lignite were carried out by using a drop tube furnace reactor at 1000℃～1400℃ and atmospheric pressure. The specific surface area and pore structure of the coke from the pyrolysis were measured with carbon dioxide absorption at 273K. It was found that the weight loss of coal increases with the pyrolysis temperature; the weight loss of all the three coals from pyrolysis at high temperature exceeds their respective volatile matter contents from the proximate analysis. However, the three coals of different ranks are also different in the pyrolysis characteristics. The specific surface area of Binxian coal increases after pyrolysis; however, it may decrease when the pyrolysis temperature was higher than the ash melting temperature. SEM characterization indicates that the ash on the surface of Binxian char is in fusion state at high temperature. Furthermore, the correlations between the weight loss and pyrolysis temperature for the three coals was obtained through data regression.
Abstract: The co-slurryability of anthracite and modified sewage sludge has been investigated with two dispersants of naphthalene sulfonate sodium formaldehyde condensate and sodium polycarboxylate. The results show that co-slurryability concentration is higher than 60% while the mass ratio of dry sewage to coal is lower than 4∶100. With increasing the mass ratio of dry sewage, co-slurryability concentration decreases. The stability of coal-watersewage slurry becomes better than that of coal-water slurry. When the ratio of dry sewage to coal is 4∶100, the period of stability is more than 160h, similar to the coal-water slurry with stabilizer B. Coal-water-sewage slurry is pseudoplastic fluid and favorable to transportation. The loose floccules characteristic, honeycomb surface and great adsorption ability of sewage play the key role in improvement of concentration, stability and rheology of the coal-water-sewage slurry.
Abstract: Char particle gasification belongs to a classic noncatalytic gas-solid reaction.The soild structure would be changed with reaction, so a structural factor reflecting the surface area evolution of the soild particle was considered in the particle gasification model. The detailed diffusion-reaction model of a char particle gasification with carbon dioxide was developed, which is limited in the kinetics controlling region. A simple structural factor was adopted in the reaction rate term of the model. The modeling results show a good accuracy comparing with that of Random Pore Model. Moreover, the carbon conversion of a particle with a different initial porosity as well as the influence of gasification temperature and reactant partial pressure were investigated.
Abstract: The reaction characteristics of gasification with H2O or H2O/H2 and the structure of Shenfu coal char pyrolyzed at 1200℃ were studied at 875℃~950℃ and at ambient pressure by TGA. There are two stages during the char gasification with H2O/H2: At first stage, the gasification rate is higher because of steam reaction with hydrocarbon side chains and oxygen containing function groups; at second stage, the gasification rate becomes lower because of steam reaction with residual aromatic carbon structure. When the gasification is performed with H2O/H2 , the carbon conversion is lower. It can be seen from the SEM photos of coal char that there are a large number of slots, pores and fragments, and lots of slots and pores are covered by those fragments. The fragments are reduced and diminished and the slots are exposed on the surface of residual coal char with the char gasification. Moreover, the carbon conversion curves of the gasification with H2O and H2O/H2 are remarkably different.
Abstract: The effects of K2CO3， Fe2O3 on catalytic combustion reactivity of different rank fuels such as lignite, bituminous coal, anthracite and graphite were investigated by a synthetical thermal analyzer. The results show that the type and content of catalysts, particle size and rank of fuel are important factors influencing catalytic combustion. When K2CO3 and Fe2O3 were added, ignition temperature of anthracite decreases from 458℃ to 319℃ and 405℃, respectively. And its combustion rate increases from 11.94%/min to 26.40%/min and 17.66%/min, respectively. There are not evident effects of K2CO3， Fe2O3 on decreasing ignition temperature of lignite and bituminous coal, but ignition temperature of anthracite and graphite decreases remarkably. With increasing rank of fuel, extent of decreasing ignition temperature is enhanced. Due to different factors led to changes of ignition temperature and combustion rate which changes are different too when catalyst is present.
Abstract: The large-scale utilization of biomass pyrolysis oil directly as high-grade energy resources has been quite limited due to its high water content and acidity. The water and acid compounds as a whole, were separated from the pyrolysis oil by molecular distillation. One fraction obtained is rich in acid compounds, and the others are refined biooilⅠ(heavy distillate fractions) and Ⅱ(room temperature condensate ) which have lower water content, weaker acidity and higher heating value. The physical properties of the crude and refined biooil, such as the pH value, heating value and water content were studied. The results indicated that water and acid compounds are separated effectively from the crude bio-oil. The content of carboxylic acids in crude biooil is about 18.85%, while that in the refined biooilⅠand Ⅱ is decreased to 0.96% and 2.2%, respectively.
Abstract: The main components of biodiesel including methyl oleate, methyl palmitate, methyl stearate, methyl linoleate and methyl laurate were modified at 250℃~350℃ using HZSM-5 zeolite catalyst to decrease the cold filter plug points(CFPP) of biodiesel. The influences of temperature and vacuum on the cold filter plug points(CFPP), coke deposits and iodine value were studied. The results show that at 300℃~350℃ an significant decrease of cold filter plug points is made, and the amount of coke deposits is less than 5%; meanwhile, the iodine value of methyl oleate is reduced. However, the iodine values of modified saturated fatty acid esters are increased. For the modification of methyl linoleate, the cold filter plug points of modified product do not decrease unless it is reacted at 350℃, and the amount of coke deposits is more than 10%. As the biodiesel from the transesterification of animal fats with methanol（AFE）is modified, the cold filter plug point(CFPP) can be decreased by 19℃ at 325℃ and 0.01MPa. Meanwhile, the acid value of the biodiesel is less than 0.6mg/g, the iodine value(I.V) is 44.32g/100g, the kinematic viscosity(μt) is 4.397mm2/s, and the amount of coke deposits is less than 5% .
Abstract: Slurry-bed hydrogenation processing conditions of FCC diesel oil were optimized, and hydrodesulfurization(HDS) and hydrodenitrogenation(HDN) kinetics were also studied over slurry-bed hydrogenation catalyst (SP25). The results indicated that the catalyst activity increased with increase of reaction temperature(t), pressure(p), catalyst additional weight(wcatatlyst) and reaction time(t). The optimal process conditions were t=350℃, p=6MPa, wcatatlyst= 6%, t=2h. The results of catalyst recycling performance suggested that catalyst SP25 possessed good activity stability. Kinetic data showed that the FCC diesel oil HDS reaction could take place in two reaction stages. The first stage is HDS of benzothiophenes(BTs), which are easier to be hydrodesulfurized among sulfur-containing compounds in FCC diesel oil. The reaction activation energy is 70.00kJ/mol. The second is HDS of dibenzothiophenes(DBTs), which are more difficult to be hydrodesulfurized. The reaction activation energy is 85.65kJ/mol. The reaction activation energy for diesel HDN reaction is 79.91kJ/mol. Alkyl-DBTs, especially DMDBTs were the the most difficult to be removed heteroatom-containing(S and/or N) hydrocarbon compounds in hydrotreating reaction.
Abstract: Thermal cracking and hydrogen transfer reactions occurred in FCC naphtha cracking for propylene were studied on pilot riser FCC unit. Influence of operation parameters (reaction temperature, catalyst to oil ratio, resident time) on propylene selectivity, thermal reaction and hydrogen transfer reactions were investigated and thermal cracking reaction and hydrogen transfer reactions were discussed at maximal value of propylene selectivity. The result showed proper reaction temperature, catalyst to oil ratio and short reaction time may detriment thermal cracking reaction, hydrogen transfer reactions , and get high propylene selectivity.
Abstract: Pd/γ-Al2O3-TiO2catalysts with 1% palladium loading were prepared by mixed sol-gel and mechanic mixing methods. Their activity for complete oxidation of ethanol and acetaldehyde was tested. The results showed that Pd/γ-Al2O3-TiO2catalyst prepared by mixed sol-gel method is more active than Pd/TiO2 and Pd/Al2O3 separately for simultaneously oxidation of ethanol and acetaldehyde. The conversions of ethanol and acetaldehyde over Pd/γ-Al2O3-TiO2 at 150℃ were 98.9% and 98.5%, respectively; the catalyst also shows a good stability under these conditions. The bulk phase and surface characterizations like XRD, SEM and FT-IR showed that there may be a strong interaction between γ-Al2O3 and TiO2 on Pd/γ-Al2O3-TiO2, which brings on a moderate specific surface area and pore volume. γ-Al2O3 may take part in the formation of catalyst surface structure, which may be favorable for the catalytic oxidation of ethanol and acetaldehyde.
Abstract: K3PO4, K2HPO4, and KH2PO4 as activating agents were added into the aqueous solution of amino acid salts glycine (GLY) to form activated absorbents (AAb) for CO2 capture. The performances of GLY and AAb for CO2 capture were evaluated using a membrane contactorregeneration cycled setup. The effects of activating agent concentration and flow rate on overall voluminal mass transfer coefficient, mass transfer flux, and capture efficiency were studied. The phosphates exhibited remarkable activating effects on CO2 capture in the membrane contactor; the activation extents of the phosphates were in the order of PO43－＞HPO42－＞H2PO4－. A small amount of activating agent is sufficient to promote the CO2 capture. The changes of hydrodynamics in the membrane contactor can improve mass transfer performance and enhance mass transfer flux to a certain extent; the essential factor for enhancing the mass transfer efficiency in membrane gas absorption is the performance of absorbents used.
Abstract: A series of Mn-Mg-Al-O hydrotalcite precursors with M(II)/Al(III) molar ratio of 3 were prepared by co-precipitation method; corresponding mixed oxides were obtained after calcinations at 500℃. The Mn-Mg-Al-O catalysts were characterized by XRD. Their performance for NOx oxidationstorage was investigated by adsorption measurements at constant temperature with or without SO2 and the desorption of stored NOx was also investigated by TPD under N2. The results showed that Mn was well dispersed in the precursors. Mg2MnO4 was the major active component after calcinations. Mn was catalytically active for the oxidation of NO and exhibited certain NOx storage capacity. Mg was the major component for NOx storage; NOx were stored with the formation of the nitrate that can be decomposed to NOx at 300℃~600℃ under N2. The NOx storage capacity was decreased by the presence of SO2.
Abstract: Several catalysts of heteropoly compounds (HPCs) with the performance of NOx adsorption-decomposition were prepared by means of ethanol-extraction and impregnation. The catalysts were characterized by IR, XRD and TEM and evaluated in a fixedbed reactor. The results showed that tungsten containing HPCs were superior to molybdenum containing HPCs for NOx adsorption; with the increase of the number of molybdenum atoms substituted by tungsten in H3PMo12-xWxO40（x=1、3、6、12）, its NOx adsorption efficiency increased. Titania and carbon nanotube (CNT) were good supports for H3PW12O40(HPW); CNT performed better than titania on the adsorption of NOx. When TiO2 was calcinated at 500℃ and the HPW loading was 20%, the NOx adsorption efficiency of HPW/TiO2 reached 62.8%. Mixed HNO3/H2SO4 with a volume ratio of 1∶ 3 could produce functional groups such as COO- and C-O on the surface of CNT, which could enhance the dispersion of CNT in the aqueous solution. HPW/CNT catalyst prepared with HNO3/H2SO4modified CNT as support and using water as impregnation solvent was superior to that using ethanol as impregnation solvent; with the HPW loading of 70%, the adsorption efficiency of NOx by HPW/CNT reached 73.5%. The process effectiveness for NOx decomposition into N2 was confirmed by GC-MS analysis.
Abstract: Catalytic activity and deactivation of a Cu-Ce/AC (activated carbon supported copper and cerium) catalyst-sorbent for oxidation of adsorbed phenol was investigated. Results show that phenol adsorption capacity and oxidation activity of Cu-Ce/AC decrease with an increase in adsorption-oxidation cycles. Initial phenol oxidation temperature of Cu-Ce/AC increases by 25℃ in 5 cycles. The deactivation of the catalyst is attributed to the formation of organic residues from oxidative coupling of phenol, which covers the Ce and Cu sites on the surface. C—O—C and C—OH groups were observed in the residues.
Abstract: The natural gas adsorbents were prepared with KOH as activation agent and petroleum coke as feed under low activation ratio mKOH/mC of 2. The influences of promoters like KNO3, NaNO3, Mg(NO3)2, Ni(NO3)2 and HJ on the methane storage performance of the adsorbents were investigated. The mechanism for the enhancement in the adsorbent capacity by using promoter was analyzed in detail. The results show that the adsorbents with good storage performance can be obtained by adding suitable amounts of KNO3, Mg(NO3)2, Ni(NO3)2 or HJ into mixed activation materials. Furthermore, Mg (NO3)2, Ni (NO3)2 coupling with HJ gives excellent co-activation effect on the adsorbents prepared. The methane mass uptake and discharging volume of the adsorbent Mg3HJ2, prepared with 10% (mass ratio of the promoter to coke) of Mg (NO3)2 and HJ, reaches 0.143 and 117.1, respectively, under 25℃ and 3.5MPa. The storage capacity of Mg3HJ2 is even higher than that of the adsorbent FS3 obtained under the activation ratio of 3 without using any promoter.
Abstract: Spin-polarized density functional theory (DFT) calculations have been performed on the structure and stability of Fe2C. It is found that orthorhombic Fe2C is more stable than hexagonal Fe2C by 0.16eV on the basis of the computed cohesive energies. The structures and stability of the orthorhombicFe2C low index surfaces have also been investigated at the same level and the low index surfaces have the decreased stability order of (011) > (110) > (100) > (101) > (001). Comparison of the most stable Fe3C, Fe4C and Fe2C surfaces shows that there is no linear correlation of surface energy and carbon content. And comparison of their most stable surfaces with the body-centered cubic Fe shows that these carbide surfaces have lower surface energies than the most stable (110) surface of body-centered cubic Fe, indicating that the surface thermodynamics favor carburization at Fe surfaces.
Abstract: High Mo loading MoSiOx mesoporous composite was synthesized in strongly alkaline media with addition of HAcac. XRD, N2 adsorption-desorption, ICP-AES as well as Py-FTIR were used for characterization. The results show that MoSiOx composite possess regular pore structure, large pore size, very large pore volume and high specific surface area. Mo species is highly distributed in MoSiOx with a loading higher than 6.3%. The acidic sites of L types contribute to the medium strong to strong acidity of MoSiOx. Results of catalytic performances show that MoSiOx has high diesel HDS activity, and the sulfur content in the treated diesel product is lower than 10 ×10-6. Both NaOH and HAcac are key factors for MoSiOx synthesis, and the amount of NaOH and HAcac adding should be controlled strictly.
Abstract: The thermal stability of mercury in Jincheng (JC) coal was studied with TPD-AFS system. An Attempt was made to identify the occurrence of the forms of mercury in JC coal according to its thermal stability. The mercury released at 200℃～300℃ is associated with the sulphate minerals that can be leached by HCl and decomposed at lower temperature. The part of mercury released at 300℃～600℃ is associated with pyrite that can be leached by HNO3, while a part of mercury is associated with the organic matters in JC coal. The mercury released at 900℃～1200℃ is associated with silicate minerals that can be leached by HF and decomposed at higher temperature. In general, the most of mercury in JC coal associated with minerals and a small fraction of mercury associated with organic matters in coal.
Abstract: The characteristics of biomass gasification in a fluidized bed with porous media as bed material were investigated by experiments. The effects of gasification temperature (600℃~900℃), oxygen enrichment in gasifying agent (0.21~0.50), steam flux and type of porous bed materials on gas composition were analyzed. The results show that the content of combustible gas increases with increasing gasification temperature. The hydrogen composition is improved from14.52% to 19.71%, but the CO composition is lowered from 43.41% to 36.41% by increasing the oxygen enrichment. There exists an optimum value for the steam flux during gasification. Different porous bed materials have different catalyses for the formation of H2, CO and the cracking of hydrocarbons.
Abstract: Catalytic pyrolysis of Chinese Daqing atmospheric residue on a commercial fluid catalytic cracking (FCC) catalyst was investigated in a confined fluidized bed reactor. The results show that the commercial FCC catalyst has good capability of cracking atmospheric residue to light olefins. The analysis of gas samples shows that the content of total light olefins in cracked gas is above 80%. The analysis of liquid samples shows that the content of aromatics in liquid samples ranges from 60% to 80%, and it increases with the enhancement of reaction temperature. The yield of total light olefins shows a maximum with the increase of reaction temperature, the weight ratios of catalyst-to-oil and steam-to-oil, respectively. The optimal reaction temperature, the weight ratios of catalyst-to-oil and steam-to-oil are about 650℃, 15 and 0.75, respectively.
Supervisor：Chinese Academy of Sciences
Sponsors by：Shanxi Institute of Coal Chemistry, Chinese Academy of Sciences Chinese Chemical Society
