Quantitative Analysis of Methanol in Methanol Gasoline by Calibration Transfer Strategy Based on Kernel Domain Adaptive Partial Least Squares(kda-PLS)

The application of near-infrared(NIR)spectroscopy combined with multivariate calibration methods can achieve the rapid analysis of methanol gasoline.However,instrumental or environmental differences found for spectra make it impossible to continuously apply the previously developed calibration model.Therefore,the calibration transfer technique would be required to solve the time-consuming and laborious problem of reestablishing a new model.In this work,a calibration transfer method named kernel domain adaptive partial least squares(kda-PLS)was applied to the calibration transfer from the primary instrument to the secondary ones.Firstly,wavelet transform(WT)and variable importance in projection(VIP)were employed to enhance the predictive performance of the kda-PLS transfer model.Then,the results found for the calibration transfer by piecewise direct standardization(PDS)and domain adaptive partial least squares(da-PLS)were compared to verify the calibration transfer(CT)effect of kda-PLS.The results point that the kda-PLS method can transfer the PLS model developed on the primary instrument to the secondary ones,and achieve results comparable to the those of reestablishing a new PLS model on the secondary instrument,with R_(P)^(2)=0.9979(R_(P)^(2):coefficients of determination of the prediction set),RMSEP=0.0040(RMSEP:root mean square error of the prediction set),and MREP=3.03%(MREP:mean relative error of the prediction set).Therefore,kda-PLS will provide a new method for quantitative analysis of methanol content in methanol gasoline.

Fabrication of a nano-sized ZSM-5 zeolite with intercrystalline mesopores for conversion of methanol to gasoline

Carbon deposition during methanol to hydrocarbons leads to the quick deactivation of ZSM-5 catalyst and it is one of the major problems for this technology. Decreasing the crystal size or introducing mesopores into ZSM-5 zeolites can improve its diffusion property and decrease the coke formation. In this paper, nano-sized ZSM-5 zeolite with intercrystalline mesopores combining the mesoporous and nano sized structure was fabricated. For comparison, the mesoporous ZSM-5 and nano-sized ZSM-5 were also prepared. These catalyst samples were characterized by XRD, BET, NH3-TPD, TEM, Py-IR and TG techniques and used on the conversion of methanol to gasoline in a fixed-bed reactor at T=405 degrees C, WHSV =4.74 h(-1) and P=1.0 MPa. It was found that the external surface area of the nano-sized ZSM-5 zeolite with intercrystalline mesopores reached 104 m(2)/g, larger than that of mesoporous ZSM-5 (66 m(2)/g) and nano sized ZSM-5 (76 m(2)/g). Catalytic lifetime of the nano-sized ZSM-5 zeolite with intercrystalline mesopores was 93 h, which was only longer than that of mesoporous ZSM-5 (86 h), but shorter than that of nano sized ZSM-5 (104 h). Strong acidity promoted the coke formation and thus decreased the catalytic lifetime of the nano-sized ZSM-5 zeolite with intercrystalline mesopores though it presented large external surface that could improve the diffusion property. The special zeolite catalyst was further dealuminated to decrease the strong acidity. After this, its coke formation rate was slowed and catalytic lifetime was prolonged to 106 h because of the large external surface area and decreased weak acidity. This special structural zeolite is a potential catalyst for methanol to gasoline reaction. (C) 2016 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B.V. and Science Press. All rights reserved.

Introduction of table sugar as a soft second template in ZSM-5 nanocatalyst and its effect on product distribution and catalyst lifetime in methanol to gasoline conversion

Methanol to gasoline reaction was investigated on two prepared ZSM-5 catalysts. The first one was a conventional catalyst denoted as ZSM-5（C） and the other was a hierarchical catalyst-ZSM-5（S） which was prepared by incorporation of table sugar in catalyst gel during the synthesis procedure. The catalysts were characterized by FTIR, XRD, FE-SEM, N2 adsorption-desorption, NH3-TPD and TGA analytical technics. The proposed material showed pore modification as well as acidity moderating properties in ZSM-5 catalyst. The methanol to gasoline reaction was conducted in a fixed bed reactor with a WHSV of 1.5 h-1.Methanol conversions, gasoline yield and selectivity in production for the synthesized catalysts were determined by gas chromatography method. The sugar modified catalyst converted more methanol than the conventional one and an enhancement in catalyst’s life time was observed. The selectivity to aromatics and durene were reduced compared to the conventional catalyst, so the gasoline quality was also further improved. The coking rate of catalysts was calculated employing TGA method. A reduction in coking rate and an increase in coke capacity of the modified catalyst were observed.

Effects of different mixing ratios on emissions from passenger cars fueled with methanol/gasoline blends

Regulated and unregulated emissions from four passenger cars fueled with methanol/gasoline blends at different mixing ratios （M15,M20,M30,M50,M85 and M100） were tested over the New European Driving Cycle （NEDC）.Volatile organic compounds （VOCs） were sampled by Tenax TA and analyzed by thermal desorption-gas chromatograph/mass spectrometer （TD-GC/MS）.Carbonyls were trapped on dinitrophenylhydrazine （DNPH） cartridges and analyzed by high performance liquid chromatography （HPLC）.The results showed that total emissions of VOCs and BTEX （benzene,toluene,ethylbenzene,p,m,o-xylene） from all vehicles fueled with methanol/gasoline blends were lower than those from vehicles fueled with only gasoline.Compared to the baseline,the use of M85 decreased BTEX emissions by 97.4%,while the use of M15 decreased it by 19.7%.At low-to-middle mixing ratios （M15,M20,M30 and M50）,formaldehyde emissions showed a slight increase while those of high mixing ratios （M85 and M100） were three times compared with the baseline gasoline only.When the vehicles were retrofitted with new three-way catalytic converters （TWC）,emissions of carbon monoxide （CO）,total hydrocarbon （THC）,and nitrogen oxides （NOx） were decreased by 24%–50%,10%–35%,and 24%–58% respectively,compared with the cars using the original equipment manufacture （OEM） TWC.Using the new TWC,emissions of formaldehyde and BTEX were decreased,while those of other carbonyl increased.It is necessary that vehicles fueled with methanol/gasoline blends be retrofitted with a new TWC.In addition,the specific reactivity of emissions of vehicles fueled with M15 and retrofitted with the new TWC was reduced from 4.51 to 4.08 compared to the baseline vehicle.This indicates that the use of methanol/gasoline blend at a low mixing ratio may have lower effect on environment than gasoline.