Abstract: Ontario-Hydro method (OHM) and semi-continuous mercury emission (SCEM) were used to study the effects of the existing air pollutant control devices on mercury emission in coal-fired power plants. The results indicate that more than 50% of Hg0 is oxidized into Hg2+ by selective catalytic (V2O5/TiO2) reduction (SCR), but SCR itself couldn't control mercury emission. The collection of fly ash by electrostatic precipitator (ESP) directly lowers the proportion of particle mercury in the flue gas. For water soluble Hg2+, wet flue gas desulphurization (FGD) could control mercury emission by absorbing Hg2+ in flue gas. Most of Hg2+ is reduced into Hg0 by reacting with SO32- and HSO3- in FGD slurry, which results in the decrease in mercury control efficiency. At the same time, it leads to the secondary emission of mercury, and it is more serious when SCR is in service.
Abstract: The pyrolysis behavior of solvent extracts (hexane solubles HS, asphaltenes A, preasphaltenes PA and THF insolubles THFIS) from a direct coal liquefaction residue (SHR) of Shenhua process were investigated by thermogravimetric analysis (TGA) and temperature programmed decomposition coupled with a mass spectrometry (TPD-MS) techniques. An attempt was made to understand the relationship between the cracking and hydrogenation activities. It shows that the hydrogenation activity of the extracts is related to their cracking ability. The synergetic effect among the fractions inhibits some of the components in HS and A fractions releasing through evaporation at 450℃ but cracking in 400℃~450℃ as free radicals. Then a positive effect can be observed. However, the presence of PA enhances the polymerization of the free radicals and then results in a negative effect on liquefaction of SHR.
Abstract: Seven partial demineralized coal samples （which basically contain only silicon and alumina minerals）were studied. The raw coals with different ranks were treated with HCl and HNO3. The transformation behavior of sulfur in coals to char and the influence of silicon, aluminum and carbon were studied through a temperature programmed decomposition (TPD) and a temperature programmed oxidation (TPO) process. The results reveal that both the carbon content and the weight ratio of Si/Al affect the sulfur retention ratio in char. The retention ratio of sulfur in char increases with the increase of carbon content, but it reverses when the carbon content is around 90%. It is attributed to the significant change of the sample structure around this carbon content. For the acid treated coals from the same rank, the sulfur retention ratio in chars decreases with the increase of Si/Al weight ratio due to the inhibition effect of silicon on the secondary reaction between the gaseous sulfur-containing components and the char.
Abstract: The effect of drying condition and particle size of sewage sludge on its co-slurry ability with Shenfu coal was investigated with naphthalene condensate as dispersant. The results show that the concentration of coal-water-sewage (CWS) slurry is greatly improved when the sewage sludge was dried and milled before preparation of the slurry. It is beneficial to raise the concentration of CWS slurry with increasing drying temperature which has a great effect on particle size distribution. With increase in drying temperature the surface mean diameter of milled sewage sludge falls and the apparent viscosity of CWS slurry decreases. When the drying temperature is above 105℃, there is no obvious change of grindability of the dried sewage sludge and the apparent viscosity of CWS slurry. The smaller particles of sewage sludge improve the packing efficiency of coal to a certain extent, resulting in the apparent viscosity of CWS slurry decrease.
Abstract: The hydrogen-rich gas production by co-gasification of coal and biomass was studied in a bench-scale fluidized bed and the effects of Equivalence Ratio (ER), steam/carbon ratio (Fs/Fc), biomass/coal ratio and biomass type were examined in the temperature range of 850℃~1050℃. The results show that the concentration of carbon dioxide and gas yield increase with the rise of ER, while the concentrations of carbon monoxide, hydrogen and methane decrease. With the increase of Fs/Fc weight ratio, the concentrations of carbon dioxide and methane increase, while those of carbon monoxide and hydrogen decrease, and the gas yield decreases following a slight increase. The concentration of carbon dioxide, hydrogen and methane increases with the increase of biomass/coal ratio, but that of carbon monoxide decreases, and the gas yield increases at first and then decreases. Coal and biomass blend can be co-gasified with as high as 50% of biomass. Among the three types of biomass used, coal/sorghum stalk gasification has the highest hydrogen concentration, and the order of gas yield for various fuels is as follows: coal/pine sawdust>coal/sorghum stalk>coal/rice straw>coal. In this experiment, the maximum volume content of hydrogen in gas and hydrogen yield can reach 37.25% and 0.54m3/kg, respectively.
Abstract: A Micro Fluidized Bed Reaction Analyzer (MFBRA) was used to study the pyrolysis of biomass in argon. Through on-line pulse feeding of reactant and continuously monitoring the composition changes of gas product, the MFBRA enables the measurement of reaction rates at arbitrary temperatures, the deduction of kinetic parameters and the analysis of reaction mechanism. By applying to biomass pyrolysis this article found that the pyrolysis reaction can finish in about 10s, which is much shorter than the other literature values obtained in larger fluidized bed reactors but very close to the theoretically anticipated values. The detected evolving sequences of different gas species and the deduced kinetic parameters demonstrate further that the reactions between/among the formed different gas species in pyrolysis prevail to certain degree and there are different pathways for forming the different gas species. The activation energy and pre-exponential factor derived by treating the pyrolysis gas as a single product are 11.77kJ/mol and 1.45s-1, which are obviously lower than the literature values measured in thermogravimetric analyzers.
Abstract: Esterification of acetic acid (AC), propanoic acid (PA) and a mixed acid (AC + PA + acrylic acid) as well as real bio-oil with ethanol under supercritical CO2 (scCO2) conditions were investigated. It was found that these carboxylic acids could afford much higher conversions under scCO2 condition in comparison with esterification at atmosphere pressure, revealing the promoting effect of scCO2 as a result of that the formed esters are prone to be phase-transferred into the scCO2 phase. Since raising pressure at constant temperature can enhance the dissolving power of scCO2, it was observed that esterification conversion increased with pressure. The results esterifying these acids separately showed significant difference in their conversions, whereas simultaneous esterification of the mixed acid mixture afforded very close conversions, suggesting that a transesterification mechanism might occur in the case of simultaneous esterification under scCO2. The appropriate operation conditions for upgrading bio-oil by scCO2 extractive esterification were determined as at 80℃ and 28.0MPa for 3.0h. Under this condition, the total acid conversion could reach up to 86.78%. pH value for the upgraded bio-oil increased from 3.78 to 5.11. The total volatile components in the upgraded bio-oil approached up to 100% at 140℃.
Abstract: Pd/Al2O3, Pd/Ce/Al2O3, Pd/Mn/Al2O3 and Pd/La/Al2O3 catalysts were prepared by the impregnation method and characterized by BET and XRD analysis. The performance of catalysts for CO, H2 and CH4 combustion were explored in a fixed bed reactor. The results show that doping of La, Ce or Mn to catalyst can lead to the decrease of specific surface area and pore volume. And the doping of Ce can obviously improve the catalytic activity and thermal stability, while the doping of La don't improve catalytic activity, but enhance the thermal stability of catalysts under high-temperature calcinations. The doping of transition metal Mn leads to an enhancement of the combustion activity, whereas can accelerate the transition of γ-Al2O3 to α-Al2O3. It is also found that the ignition sequence of CO and H2 varies for different catalysts, but all catalysts show similar activity for CO and H2 combustion that can quickly conduct at low temperature, and the combustion characteristic temperature of them is far below that of CH4.
Abstract: Amphiphilic catalyst was synthesized and used in the aquathermolysis of extra-heavy oil to reduce its viscosity. The catalyst exhibits good performance in the aquathermolysis at 200℃ and the viscosity is reduced by 96.26% for the extra-heavy oil. The chemical and physical properties of heavy oil both before and after reaction were investigated by gas chromatography (GC), fourier transform infrared spectra (FT-IR), elemental analysis (EL), molecular weight analysis (VPO) and nuclear magnetic resonance (NMR). The results indicated that the content of resin and asphaltene is decreased and the average molecular weight of heavy oil and asphaltene is reduced after the catalytic aquathermolysis. The H/C ratio of heavy oil, resin and asphaltene is increased. The amount of sulfur in the heavy oil is also decreased after the treatment. A series of polymerization reactions take place in the course of aquathermolysis; the amphiphilic catalyst may depress the polymerization reactions while enhance the aquathermolysis. The pyrolysis of asphaltene plays a very important role in the viscosity reduction. During the aquathermolysis, many reactions such as pyrolysis, hydrogenation, ring opening, ring closing and desulfuration concerning C－S, C－N, C－O, C－C, C=S, C=O, C=N and C=S bonds are involved, which attributes to the reduce of viscosity and improvement of the heavy oil quality.
Abstract: The phase behavior of Liaohe vacuum residue － n-pentane system was investigated with visual observation in a set of Hg-free PVT equipment with two cells and a sight window designated by RUSKA Co. Based on the observation, the p-t phase diagrams with the verging lines of phase transition such as liquid-liquid and liquid-liquid-vapor regions were protracted. The phase characteristics for such system were discussed at 140℃～190℃, 1.0MPa～10.0MPa and the mass ratio of solvent to oil (ms/mo) of 3.0~6.0. Under the experimental conditions, the p-t phase diagram is divided into four regions of single liquid, liquid-liquid, liquid-liquid-vapor and liquid-vapor. The phase transition pressures from single liquid to liquid-liquid region are obviously affected by the ms/mo ratio; the phase transition pressure increases with the ms/mo ratio. However, the ms/mo ratio exhibits little effect on the range of liquid-liquid-vapor region. Based on these results, the operating region suitable for the Liaohe vacuum residue － n-pentane deasphalting process was determined.
Abstract: The effects of four free radical initiators including azodiisobutyronitrile (AIBN), di-tert-butyl peroxide (DTBP), sulfur(S) and iodine(I2) on the autoclave-style visbreaking of three vacuum residues were investigated under the reaction conditions of 390℃～410℃ and the initiator dosage of 0~3000×10-6 according to free radical chain reaction mechanism of thermal-cracking of vacuum residues. The improvement mechanisms of the free radical initiators were studied by analysis of the viscosity and chemical composition of the processed oil samples. The results show that the free radical initiators improve the visbreaking of different-base vacuum residues， in which the order of improvement is LHVR≥GDVR>DQVR. The improving effect, which is dependent on the chemical-physical character of the processed residues, could be outstanding at lower reaction temperatures. The effect of I2 or S under the same reaction condition is twice higher than that of AIBN or DTBP, which could be attributed to the circulated initiation of ‘active atom’ originated from the inorganic HI or H2S. Compared with S, the improvement of iodine is better.
Abstract: Influence factors of long-term storage stability of the Venezuela Orinoco AR visbreaking products were studied by the changes of kinematic viscosity，TAN（Total Acid Number），weight loss，resin and asphaltene contents of visbreaking products in different storage conditions. It was found that the long-term storage stability of the visbreaking products is influenced by oxidative polycondensation, light components' volatilization and non-oxidative polycondensation, among which the effect of oxidative polycondensation is the most significant. Free radical reaction did not terminate after thermal reaction finished. The long-term storage stability of visbreaking products was closely related to free radical. Aromatic carbon ratios of resin and asphaltene of all visbreaking products were lower than that of the original visbreaking product. Asphaltene did not occur polycondensation, so visbreaking products could hardly arise layer phenomenon and was more stable.
Abstract: Laser Raman spectroscopy (LRS) was used to characterize the NiMoP impregnation solution and dried samples of NiMoP impregnated on γ-Al2O3. The effect of phosphorous content on the structure of the active phases in NiMoP impregnation solution and that during the impregnation process was studied. The LRS results indicate the active phases in NiMoP impregnation solution with lower phosphorous content are composed of several heteropoly compounds such as NixH6-2x\[P2Mo5O23\], NixH7-2x\[PMo11O39\] or NixH3-2x \[PMo9O31\] and NixH3-2x\[PMo12O40\]. NixH6-2x\[P2Mo5O23\] is dominant when phosphorous content increases. In addition, these active phases in NiMoP impregnation solution with lower phosphorous content are converted to seven poly-molybdate when the impregnation solution is impregnated into the cavities of γ-Al2O3, while higher phosphorous content hinders this conversion.
Abstract: Co-ZrO2 precipitated catalyst is treated by reduction in H2 at 400℃, Oxidation of the reduced catalyst in air at room temperature, and reduction again in H2 at 250℃ or 400℃. The influence of this reduction-oxidation-reduction treatment on the properties of Co-ZrO2 precipitated catalyst was investigated by TPR, N2 physical sorption, H2-TPD, XPS, XRD, and Raman spectra; the performance of treated catalysts in Fischer-Tropsch (F-T) synthesis was considered in both slurry phase and fixed bed reactors. The results showed that cobalt in the catalyst is in the form of Co3O4 with little change in particle sizes after the reduction-oxidation process. The concentration of cobalt on the catalyst surface is reduced a little after the treatment, but the amount of H2 uptake is increased significantly. The reduction-oxidation treatment can lower the reduction temperature of surface cobalt species. As a result, the catalytic activity of Co-ZrO2 for F-T-synthesis is improved and the selectivity to CH4 is depressed by the reduction-oxidation treatment. Furthermore, the catalyst reduced at a relatively high temperature exhibits much better performance in the fixed bed reactor.
Abstract: The aluminium-rich beta zeolite with relatively high crystallinity and nanometer size was synthesized in the neutral system, in which the lower water content and F- anion were involved. The solid aluminosilicate gel was prepared as the original materials. The effects of synthesis conditions and the calcined aluminosilicate gel properties on the crystallization products were investigated. The evolvement of Al coordination situation had also been studied during crystallization process. The crystallization products were determined by means of XRD, XRF, SEM, TEM, 27Al MAS NMR methods. The results showed that the crystallization conditions involved F- anion and H2O/SiO2 mol ratio 2.4~6.0 as well as solid aluminosilicate gel calcined at high temperature contributed to aluminium-rich beta zeolite with relative higher crystallinity and nanometer size. The solid aluminosilicate gel was calcined to lead to production of four-coordinated aluminium subjected to being transformed into beta zeolite framework. The part of six-coordinated aluminium slowly dissolved into the crystal nuclei during crystallization period. The result led to get the nanometer aluminium-rich beta zeolite at last.
Abstract: On the surface of silica gel chemically modified with γ-aminopropyltriethoxysilane and methacrylic acid, a molecularly imprinted polymer (MIP) for the selective benzothiophene recognition was prepared by using methacrylic acid as the functional monomer, ethylene glycol dimethacrylate as the crosslinker, and benzothiophene as the template molecule. The textural properties of MIP were characterized by FT-IR, elemental analysis and N2 adsorption; its static adsorption performance for benzothiophene was tested with a model gasoline. The results showed that a porous thin layer of MIP was successfully grafted on the surface of silica gel carrier. The imprinted polymer exhibits good specific benzothiophene recognition; the adsorption of benzothiophene on it accords with Langergren quasi-one kinetic equation and Langmuir isotherm of monolayer adsorption. The adsorption capacity of MIP for benzothiophene reaches 57.4×10-3, in comparison with 33.1×10-3 of the non imprinted polymer; its adsorption capacity remains almost unchanged after regeneration for many times. This may provide a new approach for deep desulfurization of gasoline to remove sulfur-containing thiophenic compounds.
Abstract: The solubility of CO2 in the mixed solution of methyldiethanolamine (MDEA) and 2-amino-2-methyl-1-propanol (AMP) was measured at 25℃, 30℃ and 40℃; the effects of CO2 concentration in gas phase, temperature and solution composition on the CO2 solubility were examined. The results indicted that the solubility of CO2 increases with the increase of gaseous CO2 concentration or the AMP content in the MDEA-AMP mixed solution, but decreases with the increase of temperature.
Abstract: The adsorption and desorption of arsenic As(V) ions with peat humic acid as an adsorbent were investigated by using hydride generation atomic fluorescence spectrometry; the optimal conditions for the adsorption of As(V) in humic acid and the recovery of As(V) through desorption from the adsorbent were obtained. The results indicated that humic acid is provided with plentiful polar groups and exhibits strong adsorption ability for metal ions. The adsorption of As(V) ion in peat humic acid follows the Freundlich adsorption equation. The acidity of aqueous solution influences the adsorption significantly; the adsorption quantity is high and stable when the solution is neutral. The adsorption rate reaches 85.49% under the optimal conditions where As(V) concentration is 1μg/mL, pH value of the solution is 7 and adsorption time is 50min~60min. The most suitable conditions for the desorption are that pH value of the solution is 14 and desorption time is 20min.
Abstract: On the basis of improving adsorption capacity of the activated carbon (AC) modified by high concentration HNO3 and KOH solution, a special microwave device was designed for further modification of AC by the heat treatment, and a kind of highly active carbon sorbent used for combined flue gas desulfurization and denitrification was prepared. Through the adsorption experiment in the simulating flue gas using modified AC, it is found that the modified AC under microwave irradiation evidently increases the adsorption capacity of SO2, and the best removal efficiency can be obtained with the AC pretreated by KOH solution and modified by microwave. The experiments indicate that the AC pretreated by high concentration HNO3 and microwave irradiation has a better removal of NO with the adsorption capacity of 36.8×10-3. The SEM pictures show the numbers of the micropores increase clearly, which is in favor of removal of pollutants. The mechanism of removing SO2 and NO with various modified methods was analyzed simply in the paper.
Abstract: Advanced reburning (AR) tests were conducted in a vertical-tube experimental system using herbaceous biomass of cotton-haulm, corn-stalk, wheat-stalk and woody biomass of phoenix tree as reburning fuels. The results show that the Rff of 20% and residence time of 0.7s are better for the reburning process. When the excess air ratio ranges from 0.7 to 0.9, and NH3/NO mol ratio (NSR) is about 1.5, the maximum efficiency of nitrogen oxides (NOx) reduction at 1273K by cotton-haulm, corn-stalk, wheat-stalk and phoenix reburning reaches 89.11%, 88.34%, 90.33% and 88.28%, respectively, which is 25%~30% higher than that by general reburning. It indicates that the biomass reburning plays a great role for the NOx reduction in AR and the ammonia-ejection plays a role for optimizing the course. In a broad range of 1173K~1473K, the AR of all tested biomass could gain NOx reduction beyond 80%. The NOx reduction can be further meliorated by adding alkali metals and alkaline earth promoters with 100×10-6 vol concentration, and the promoting effect differs from each other. The sodium carbonate and potassium carbonate can enhance the efficiency by 3%~6%; and the calcium acetate can enhance the efficiency by 4.0%~5.0% at 1273K~1473K but by nothing at 1073K~1273K.
Abstract: Coal series kaolinite is a kind of rock and a paragenetic mineral of coal. This mineral paragenesis increases the complexity of combustion of coal in kaolinite. Therefore, it is necessary to study its combustion characteristics, which is of positive significance to make good use of coal gangue resource. Taking the combustion mechanism of coke in FCC catalyst as reference, an unreaction shrinking core model for fixed carbon combustion reaction in kaolinite particle was established based on a series of hypothesis. The combustion of fixed carbon in coal series kaolinite was conducted by using an isothermal thermogravimetric method in air atmosphere. Results clearly show that the control step of fixed carbon combustion process below 700℃ is the interface combustion reaction. By means of the unreaction shrinking core model analysis and calculation of unhomogeneous particle system, the combustion kinetics parameters for fixed carbon combustion in coal series kaolinite are obtained, the value of activation energy (E) is 100.12kJ/mol, and the frequency factor (A) is 2.27×106s-1.
Supervisor：Chinese Academy of Sciences
Sponsors by：Shanxi Institute of Coal Chemistry, Chinese Academy of Sciences Chinese Chemical Society
