Detailed Hydrocarbon Analysis Research Articles

A methodology to replicate LTGC engine conditions in a single-zone model and validate gasoline surrogate formulations versus experimental measurements

In this work, surrogate fuels for three premium-grade gasoline fuels were formulated and its autoignition behavior was validated, together with that of an existing surrogate for E10 regular gasoline, by comparison to experimental data measured in the Sandia Low-Temperature Gasoline Combustion research engine facility. Surrogate fuels have been previously designed by matching fuel properties such as octane number, fuel/air stoichiometric ratio and hydrogen/carbon ratio. However, similar octane rating can be obtained with several blends that will show different ignition characteristics. To avoid this issue, the surrogate fuels shown in this paper have been formulated by matching the main components of the fuel detailed hydrocarbon analysis. Validation of the surrogates was performed by replicating engine experiments run with the real fuel in a 0-D internal combustion engine reactor model with detailed chemistry. A fitted heat-loss model had to be implemented to properly replicate the experimental in-cylinder thermodynamic conditions, which invalidates the adiabatic assumption sometimes applied to engine simulations. Furthermore, minor species present in the EGR and residuals, such as CO and NOx, had to be taken into account to replicate the experimental low-temperature heat release (LTHR) trends. Therefore, accounting for heat losses and detailed in-cylinder composition are essential to accurately simulate the engine data. The bottom dead center temperature deviation required to obtain the same combustion timing as in the experiments was used as a metric to evaluate the accuracy of simulations. The surrogates gave good performance for the whole explored range, and replication of LTHR is a key factor in matching the experimental data. Chemical kinetic analyses showed that replication of LTHR is controlled by the ability of the surrogate to properly balance radical generation from low-temperature chain branching decomposition with radical consumption from stable species. Surrogate components that act as a sink of radicals tend to suppress the LTHR of the fuel, which may lead to large deviations between simulations and experiments. Especial attention should be paid to these fuel species when selecting the surrogate components.

A novel method for examining the influence of molecular and structural properties of the asphaltene fraction on the wettability change of the calcite surface

Asphaltene deposition in the porous media of the reservoir during the production life causes serious challenges with significant economic cost. From the point of view of proactive action to prevent the formation of such precipitates, today asphaltene inhibitors are widely used in the oil industry. The successful performance of inhibitors strongly depends on molecular structure of asphaltene. This study investigates the effect of molecular-structural properties of asphaltene in four crude oil samples on calcite surface wettability. The wettability of the calcite surface is evaluated with contact angle test and micromodel. The crude oil properties are determined using DHA (Detailed Hydrocarbon Analysis) and FTIR (Fourier Transform Infrared Spectroscopy) tests, while the molecular-structural properties of asphaltene are assessed using elemental analysis, FESEM (Field Emission Scanning Electron Microscopy), NMR (Nuclear Magnetic Resonance), and FTIR techniques. Based on FTIR analysis of oil samples, the higher polarity of samples B and G compared to samples F and A can be attributed to the presence of C = O carboxylic acid stretches. In addition, DHA analysis indicates that sample B, which contains heavier compounds comprising 27.4220 % of the C14+ compounds by weight, exhibits distinct characteristics. The FESEM images demonstrate a uniform and smooth spread surface morphology of the asphaltene samples. However, the elemental analysis does not establish a correlation between the heteroelement ratios of N/C, O/C, and S/C and asphaltene adsorption tendency. FTIR and NMR analyses suggest that the wetting properties observed on the surface are mainly attributed to the high aromatic and aliphatic compounds present in the asphaltene of sample B, while the polar compounds are less influential. The results reveal that crude oil sample B exhibits the highest percentage of damage to the porous medium caused by asphaltene deposition, with a rate of 36.18 % and a contact angle of 163.53 degrees. This indicates a wetter surface of the oil compared to other samples. Samples G and A follow with contact angles of 157.34° and 153.60°, respectively. On the other hand, sample F shows the lowest wettability change on the calcite surface with a contact angle of 144.77° and only 0.08 % damage to the porous medium.

Evaluation of a prototype reverse fill/flush flow modulation-splitter system for the highly detailed separation required in industrial settings

Reverse fill/flush (RFF) differential flow modulators are a lower cost, consumable free, robust option to achieve comprehensive two-dimensional gas chromatography (GC × GC) with FID and MS dual detection. For the required highly detailed separation of all hydrocarbon classes for a petroleum industry setting thermal-based modulators are considered the “gold standard” for their high performance, but there are substantial costs involved. In an industrial setting, there is a necessary balance between the separation performance, cost of instrumentation and costs of operation. It is uncertain if an RFF modulator chromatographic performance is sufficient to achieve the demands of an industrial research laboratory as a cost-effective alternative to thermal modulation. This paper reports an evaluation of the capabilities of a new prototype RFF flow modulator with flow splitter system and its chromatographic performance relative to thermal modulation for detailed hydrocarbon analysis. The prototype RFF modulator splitter system was easy to use with straightforward method optimization due to the lack of restrictors and implementation of back pressure regulation for variable restriction. It also provided good peak shapes, accurate quantification, and maintained constant split to both detectors throughout the analysis. The data processing workflow was greatly improved with the alignment of the MS and FID traces in the software. However, the chromatographic performance of the RFF was found to be less and insufficient for detailed hydrocarbon analysis when compared to thermal modulation. The greatest discrepancy was found in the differentiation of the saturate class, specifically the alkanes, iso-alkanes, and cycloalkanes from each other and other monoaromatics. A comparable separation was found in the lower carbon range of C7-C14 while the region of C16-C22 was challenging for the RFF modulator. Overall, the detailed analysis of a middle distillate was found to be too complex for the RFF flow modulator in comparison to thermal modulator.

Comparing different methods for olefin quantification in pygas and plastic pyrolysis oils: Gas chromatography-vacuum ultraviolet detection versus comprehensive gas chromatography versus bromine number titration

In steam cracking, upstream pyrolysis oil hydroprocessing, and in many downstream processes, olefinic content is key to assess process performance and process safety risk associated with highly exothermic reactions. When looking to plastic pyrolysis oils as a potential feedstock, as well as downstream products such as pyrolysis gasoline (pygas), these materials contain unsaturated hydrocarbons which are not present in fossil feedstocks. Pygas is a product of pyrolysis and exhibits a large number of chemical structural similarities with plastic pyrolysis oils, especially in terms of olefins structure. Quantification of the unsaturation content (olefins and di-olefins) is extremely important in industry, hence the focus of this manuscript. Detailed hydrocarbon analysis with flame ionization detection is inadequate to fully characterize the hydrocarbon composition of such samples, especially when peaks are closely eluting, or even co-eluting. In this study, the gas chromatography coupled to vacuum ultraviolet (GC-VUV) detection method previously described for the analysis of liquid hydrocarbon streams11M.N. Dunkle, P. Pijcke, B. Winniford, G. Bellos. Journal of Chromatography A, 1587 (2019) 239-246. https://doi.org/10.1016/j.chroma.2018.12.026. and plastic pyrolysis oils22M.N. Dunkle, P. Pijcke, W.L. Winniford, M. Ruitenbeek, G. Bellos. Journal of Chromatography A, 1637 (2021) 461837. https://doi.org/10.1016/j.chroma.2020.461837. has been compared with comprehensive gas chromatography (GC × GC) and the industry standard for olefin quantification (i.e., bromine number titration). Although based on different methodologies, a correlation between the olefin content obtained from GC-VUV and the bromine number titration method is hereby presented.

Prediction of Retention Indices and Response Factors of Oxygenates for GC-FID by Multilinear Regression

The replacement of fossil carbon sources with green bio-oils promotes the importance of several hundred oxygenated hydrocarbons, which substantially increases the analytical effort in catalysis research. A multilinear regression is performed to correlate retention indices (RIs) and response factors (RFs) with structural properties. The model includes a variety of possible products formed during the hydrodeoxygenation of bio-oils with good accuracy (RRF2 0.921 and RRI2 0.975). The GC parameters are related to the detailed hydrocarbon analysis (DHA) method, which is commonly used for non-oxygenated hydrocarbons. The RIs are determined from a paraffin standard (C5–C15), and the RFs are calculated with ethanol and 1,3,5-trimethylbenzene as internal standards. The method presented here can, therefore, be used together with the DHA method and be expanded further. In addition to the multilinear regression, an increment system has been developed for aromatic oxygenates, which further improves the prediction accuracy of the response factors with respect to the molecular constitution (R2 0.958). Both predictive models are designed exclusively on structural factors to ensure effortless application. All experimental RIs and RFs are determined under identical conditions. Moreover, a folded Plackett–Burman screening design demonstrates the general applicability of the datasets independent of method- or device-specific parameters.

ДОСЛІДЖЕННЯ СОРБЦІЙОЇ ЗДАТНОСТІ САПОНІТОВОГО ГРАНУЛЯТУ ЩОДО ВУГЛЕВОДНЕВИХ СУМІШЕЙ У ДИНАМІЧНОМУ РЕЖИМІ

Their drawback can be explained by the high cost and regeneration complexity. That is why the usage of natural sorbents (Tashkiv saponite deposits, Khmelnitsky region). They are able to clean contaminated water from colloidal, molecular and ionic substances. Exploring the specified topic, physicochemical properties of various forms of saponites are studied; the area of their usage is defined. The paste for cleaning contaminated surfaces is developed on their basis. The research results have shown that the most effective method is to use natural saponite. The author of the article advises to conduct preliminary acid activation of clay minerals and modification of its surface multivalent metal salts. Saponite clay granulate is obtained with different time and sintering temperature. Granulation is shown to improve the strength and filtration characteristics of natural sorbents, increasing the filtration rate and the duration of the filter cycle. The influence of the granulation process on the sorption properties of the obtained granulated aluminasilicates is investigated. A detailed hydrocarbon analysis of the A-92 starting gasoline is carried out. The composition of the purified samples of the hydrocarbon mixture is evaluated with gas chromatography using saponite granulate (Octane rating = 94,013 according to the method of research) under static conditions. The structure changes of raw and acid activated saponite clay has been investigated by nitrogen adsorption method and scanning electron microscopy. Established that the porous structure of saponite clay mineral represented by micro-meso porous system with domination of micropores. Acid modification promotes the development of specific surface area (from 47,7 m2/g to 177,9 m2/g) and increase the total volume of pores (from 0,134 cm3/g to 0,201 cm3/g).

Detailed Hydrocarbon Analysis of Petroleum Products by Gas Chromatography–Mass Spectrometry

Detailed Hydrocarbon Analysis of Petroleum Products by Gas Chromatography–Mass Spectrometry

Geochemical study of the early cretaceous Fahliyan oil reservoir in the northwest Persian Gulf

Three crude oil samples from the Fahliyan Formation in ‘KG’ and ‘F’ fields in the northwest Persian Gulf, namely KG-031, F9A-3H and F15-3H for the geochemical study. In this study, the physicochemical properties, gas chromatography (GC, GC Mass) and (Detailed Hydrocarbon Analysis) DHA analyses for the collected Fahliyan oils were carried out. The API, Trace Element (Ni, V) and S% parameters indicated that the Fahliyan oil was generated from a source rock which deposited in reducing environment condition with a carbonate-shale compound lithology. Moreover, low pour point, higher S% and low viscosity parameters of “KG” sample confirmed the existence of medium oil characteristics in this field. In addition, the geochemical outcomes of GC, GC–MS and DHA analyses indicated that the ‘KG’ oils are more aromatic compared with ‘F’ oil; while biomarkers revealed that Fahliyan reservoir oil is highly mature and was formed from a carbonate source rock containing types II, III kerogen. Thus, sterane/hopane biomarkers (C24/C23 and C22/C21 ratios) revealed that Fahliyan oil originated from carbonate source rocks deposited in an anoxic to dysoxic environment, which is consistent with the above analyses. It was identified that the source rock age is early Cretaceous to late Jurassic. It can be reported that the Fahliyan oils from both fields were generated in the same source rock and have almost the same physical properties, and will have the same production strategy.

Production of high octane gasoline by catalytic cracking of petroleum gasoil with palm’s triglyceride and oleic acid

The use of gasoline with appropriate octane number will affect directly to meet superfine engine performance and avoiding from knocking effect. Improvement of gasoline quality in fluid catalytic cracking process usually is achieved by replacement of new catalyst which needs higher production cost. This research work aimed to describe the alternative method for improving gasoline octane in catalytic cracking by means of feedstock modification using mixture of vacuum gasoil and few of palm’s triglyceride and oleic acid. The experimental work of cracking reaction was performed in a fluid-bed reactor of ACE unit using REY zeolite catalysts at temperature of 530 °C and catalyst-oil ratio of 5.5 g/g. The liquid product was analyzed by a gas chromatograph of simulated distillation to determine yields of gasoline, light cycle oil and bottom product continued by a gas chromatograph of detailed hydrocarbon analysis to obtain hydrocarbon composition and calculated research octane number of gasoline. Analysis of gaseous product was performed using a gas chromatograph of refinery gas analyzer to detect yields of dry gas and LPG, whereas coke deposited on spent catalyst was analyzed using the infra-red method. From the research work, it was found that feedstock prepared from vacuum gasoil added with 5 % refined bleached deodorized palm oil and oleic acid (9:1) had increased gasoline RON from 91.8 to 98.2. The improvement of gasoline octane was contributed by the presence of double-bond fatty acid that triggered promoting effect to aromatisation and hydrogen transfer reactions in the formation of more iso-paraffins, olefins and aromatics in gasoline.

Catalyst to oil mass ratio optimization on fluid catalytic cracking process in green gasoline production

Palm oil has potential as raw material for green gasoline as renewable energy source. One of the most important variables to support the achievement optimum operating condition in the Fluid Catalytic Cracking (FCC) process was the mass ratio of catalyst to oil (c/o). The FCC process simulation was carried out by using an Advance Cracking Evaluation (ACE) unit at mass ratio c/o (4.00, 5.00, 5.56, 6.00, 6.52) w/w ASTM D3907. The quality test of the FCC product were distribution of boiling point by using Refinery Gas Analyzer (RGA) Chromatography ASTM D2504 and using high temperature distillation simulating gas chromatography ASTM D7169, octane number by using Detailed Hydrocarbon Analysis (DHA) Chromatography ASTM D6730 and coke formation by using CO Analyzer ASTM D6316. The study shown that the most optimum c/o ratio in FCC process was at ratio 6.00 w/w with the amount of dry gas product 2.48 percent w/w, LPG 27.36 percent w/w, gasoline 41.81 percent w/w, LCO 11.54 percent w/w, HCO 0.00 percent w/w, bottom 3.71 w/w, and coke 12.99 percent w/w with octane number was 84.693. It can be concluded that FCC process of the palm oil mixture feed at this ratio has better quality than PT Pertamina’s FCC feed.

Effects of the Particulate Matter Index and Particulate Evaluation Index of the Primary Reference Fuel on Particulate Emissions from Gasoline Direct Injection Vehicles

The purpose of this experimental study was to evaluate the range of particulate mass (PM) and particulate number (PN) results from gasoline direct injection (GDI) vehicles by using four test fuels with a range of particulate matter index (PMI) from 1.38 to 2.39 and particulate evaluation index (PEI) from 0.89 to 1.92. The properties of four test fuels were analyzed with detailed hydrocarbon analysis (DHA). Two passenger cars with a GDI engine were tested with four test fuels by conducting the China 6 test procedure, which is equivalent to the worldwide harmonized light-duty vehicle test procedure (WLTP). When the fuels could meet the China 6 primary reference fuel standard with PMI from 1.38 to 2.04 and PEI from 0.89 to 1.59, the PM variation of Vehicle B was from 1.94 mg/km to 3.32 mg/km and of Vehicle A was from 2.55 mg/km to 4.15 mg/km, respectively. In addition, the PN variation of Vehicle B was from 1.57 × 1012 #/km to 3.38 × 1012 #/km and of Vehicle A was from 3.02 × 1012 #/km to 4.80 × 1012 #/km. It was noted that the two different cars had a unique response and sensitivity by using the different fuels, but PMI and PEI did trend with both the PM and the PN response. All PM and PN results from the two cars had an excellent correlation R2 > 0.94 with PMI and R2 > 0.90 with PEI. Therefore, PMI/PEI would be the appropriate specification for sooting tendency in reference fuel standards of emission regulations.

Quantification of the composition of liquid hydrocarbon streams: Comparing the GC-VUV to DHA and GCxGC

Hydrocarbons analysis is important in the oil and gas industry, as stream composition has a strong impact on plant operations. The composition of hydrocarbon streams vary across a plant, which makes the selection of analytical methods challenging. Traditional methods for the evaluation of liquid hydrocarbon streams include the Detailed Hydrocarbon Analysis (DHA); however, non-traditional methods, such as comprehensive gas chromatography (GCxGC), are also utilized in the chemical industry, including Dow. This work details a comparison of analytical techniques available for such analyses, specifically, DHA and GCxGC compared to the recently introduced GC-Vacuum Ultra Violet (GC-VUV) system. Numerous liquid hydrocarbon streams were blended together to generate a composite and extensive matrix in terms of composition. Paraffin, isoparaffin, olefin, naphthene, and aromatic (PIONA) results are presented for the three techniques. All of those methods obtained relative standard deviations lower than 1.3% for five injections a day for three days. Standard addition curves were utilized to accurately quantify specific compounds in a liquid hydrocarbon stream, and these results were compared to the GC-VUV PIONA+ and DHA quantification procedures.

On-line liquid chromatography-comprehensive two dimensional gas chromatography with dual detection for the analysis of mineral oil and synthetic hydrocarbons in cosmetic lip care products

An on-line liquid chromatography-comprehensive two-dimensional gas chromatography (LC-GC×GC) separation process, combined with a dual detection system, namely triple quadrupole mass spectrometry (used as a single quadrupole - QMS) and flame ionization detection (FID), was developed for the analysis of cosmetic lip care products. The LC step was carried out by using a fused-core silica column, with this enabling the separation of mineral oil saturated hydrocarbons (MOSH), as well as polyolefin oligomeric saturated hydrocarbons (POSH), from the mineral oil aromatic hydrocarbon (MOAH) families. Each chemical class was then subjected to GC×GC-QMS/FID analysis, using a medium polarity-low polarity column combination. Notwithstanding the utility of the flame ionization detector for quantification purposes, it is obviously also desirable to obtain information on the type of hydrocarbons present (of mineral or synthetic origin), in order to identify a potential contamination source. Following method optimization, various analytical figures of merit (method linearity, intra- and inter-day repeatability, limits of detection and quantification, and injector discrimination) were measured. Specifically, for MOSH and MOAH, linearities were evaluated in the 32.5–2080 and 50–500 mg L−1 range, respectively; furthermore, intra- and inter-day repeatability values were 6.2 and 8.3%, respectively, while limits of detection and quantification were 3.5 and 11.8 mg L−1, respectively.The proposed method, enables for the first time (to the best of the authors’ knowledge), the detailed qualitative and quantitative analysis of saturated and aromatic hydrocarbons, in a single run and in a fully-automated manner. Quantities of MOSH + POSH in the cosmetic products ranged from 8.7 to 44.4% (CV values were in the 1.5–5.4% range) while MOAH contamination was found in four samples, ranging from 386 to 5869 mg kg−1 (CV values were in the 0.5–4.5% range).

Applications of thermal desorption coupled to comprehensive two-dimensional gas chromatography/time-of-flight mass spectrometry for hydrocarbon fingerprinting of hydraulically fractured shale rocks

Development of shale gas resources through the use of hydraulic fracturing has raised a multitude of environmental concerns and motivated research towards the understanding of shale gas systems. Previous research has demonstrated the potential of utilizing hydrocarbon distributions towards the fingerprinting of a potential environmental contamination event arising from shale gas operations. However, to apply hydrocarbon distributions from shale gas wells towards point-source identification and apportionment, a better understanding of hydrocarbon origins must be achieved. Here we present an efficient and repeatable thermal desorption method, as a sample introduction methodology for GC × GC analysis of shale rock samples that results in comparable chromatograms to those produced by solvent extraction. This novel and robust characterization technique of shale cores from Marcellus and Utica formations by thermal desorption followed by GC × GC enables the understanding of hydrocarbon speciation within the native rock with minimal sample preparation time and solvent use. The detailed shale chemistry gives insight into utilizing hydrocarbon differences towards point-source identification methodologies of environmental contamination events associated with unconventional gas development. Additionally, this analytical technique may provide a more detailed analysis of hydrocarbons than what is currently implemented in the industry to pinpoint the most advantageous areas to exploit by hydraulic fracturing, yet avoiding undesirable areas such as those with a high abundance of sulfur containing compounds.

Computer-Aided Gasoline Compositional Model Development Based on GC-FID Analysis

The demand for improved gasoline product quality has helped make molecular-level models become more preferred for the modern refinery. Building the molecular compositional model is an essential first step for this quantitative molecular management of gasoline streams. Gas chromatography equipped with flame ion detection (GC-FID) is commonly used in the gasoline detailed hydrocarbon analysis (DHA). The combination of GC-FID analysis and molecular-level modeling is thus very attractive. In the present study, we developed a gasoline compositional model based solely on GC-FID as input. To suppress the negative influence of peak coelution, we developed a statistics-based peak tuning algorithm to obtain individual compound resolution at higher carbon number range. Using the tuned result as input, the molecular-level gasoline compositional model was built by estimating the quantitative percentages of the species in a predefined molecular library (573 molecules). The molecular-level compositional model has good e...

Synthesis of W/HZSM-5 catalyst for simultaneous octane enhancement-desulfurization process of gasoline production

In this work, the effect of incorporating tungsten in HZSM-5 zeolites over the performance of desulfurization and octane enhancement processes of heavy naphtha was investigated. The physical and chemical characterization of the catalysts were analyzed by means of XRD, BET, NH3-TPD, TPR and XRF. The catalytic properties were determined at 5 barg, 450 °C, H2/Oil = 150 Nml/ml and WHSV = 1 h−1 inside a fixed bed reactor. The standard methods of detailed hydrocarbon analysis, gas chromatography, ASTM D-2699 and ASTM-D5453 were utilized to determine the liquid hydrocarbon compositions, detailed analyses of the off-gases, research octane number and the total amount of sulfur of the feed and products, respectively. The obtained results showed that the interaction between the Brönsted and Lewis acid sites for the W/HZSM-5 samples at low SiO2/Al2O3 ratios and consequently high acidity in the specific operating condition led to the parallel aromatization-desulfurization reactions to proceed perfectly. The total amount of sulfur decreased by 71 wt% for the SiO2/Al2O3 ratio of 20, and the aromatic component of the feed increased from 14.16 wt% to 72.82 wt% for the SiO2/Al2O3 ratio of 40; hence, RON raised from 52 to 98. Overall, by comparing the performance of the catalysts, it can be concluded that the best performance of simultaneous octane enhancement-desulfurization process was observed for the catalyst No_3, in which the amount of sulfur compounds decreased by 67.5% and the octane increased by 90%.

Determination of flash point and Reid vapor pressure in petroleum from HTGC and DHA associated with chemometrics

Flash point (FP) and Reid vapor pressure (RVP) are physicochemical properties of crude oil that are used as safety and environmental parameters. In this paper, we propose a methodology for estimating the FP and RVP for crude oil by means of detailed hydrocarbon analysis (DHA) and high temperature gas chromatography (HTGC) associated with partial least squares (PLS) regression. These techniques were used due to their direct relationship to FP and RVP. We studied 107 crude oil samples (with an API gravity range of 11.4–54.0) collected from a Brazilian sedimentary basin. The curve data derived from these two techniques were merged to better describe the true boiling point curve. Using fusion information drawn from the two chromatographic techniques (DHA and HTGC), we estimated the flash point with an average error of 5.3 °C and a coefficient of determination of approximately 0.9. While the data fusion represents an information gain in the estimation of the flash point, for to estimate the Reid vapor pressure, the HTGC data are sufficient. The PLS regression generated the best Reid vapor pressure results, with an average error of 0.4 kPa and with a coefficient of determination of above 0.99.

Compositional and Structural Analysis of Silica Gel Fractions from Municipal Waste Pyrolysis Oils

Hydrocarbon-rich pyrolysis oils produced from landfill waste and recycled plastics are potential sources for fuels and chemicals. It is well established that feedstock composition significantly affects pyrolysis oil composition and, hence, its potential uses. For example, plastics waste pyrolysis oils contain a high concentration of hydrocarbons, whereas biomass pyrolysis oils have high oxygen content. Previous studies have shown that the addition of plastics to a biomass feedstock increases the hydrocarbon content; however, a detailed analysis of hydrocarbons and polar species from pyrolysis oils produced from “real world” mixed municipal waste materials has not yet been done. Here, the silica gel fractions from unsorted landfill waste and mixed recycled plastics pyrolysis oils are analyzed by two-dimensional gas chromatography (GC × GC), field ionization mass spectrometry (FI-MS), Fourier transform infrared spectroscopy (FT-IR), and Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS)...

Inverse Opal Photonic Crystals as an Optofluidic Platform for Fast Analysis of Hydrocarbon Mixtures.

Most of the reported optofluidic devices analyze liquid by measuring its refractive index. Recently, the wettability of liquid on various substrates has also been used as a key sensing parameter in optofluidic sensors. However, the above-mentioned techniques face challenges in the analysis of the relative concentration of components in an alkane hydrocarbon mixture, as both refractive indices and wettabilities of alkane hydrocarbons are very close. Here, we propose to apply volatility of liquid as the key sensing parameter, correlate it to the optical property of liquid inside inverse opal photonic crystals, and construct powerful optofluidic sensors for alkane hydrocarbon identification and analysis. We have demonstrated that via evaporation of hydrocarbons inside the periodic structure of inverse opal photonic crystals and observation of their reflection spectra, an inverse opal film could be used as a fast-response optofluidic sensor to accurately differentiate pure hydrocarbon liquids and relative concentrations of their binary and ternary mixtures in tens of seconds. In these 3D photonic crystals, pure chemicals with different volatilities would have different evaporation rates and can be easily identified via the total drying time. For multicomponent mixtures, the same strategy is applied to determine the relative concentration of each component simply by measuring drying time under different temperatures. Using this optofluidic sensing platform, we have determined the relative concentrations of ternary hydrocarbon mixtures with the difference of only one carbon between alkane hydrocarbons, which is a big step toward detailed hydrocarbon analysis for practical use.

Investigation of the effect of HZSM-5 over HDS and reforming processes for clean gasoline production

HZSM-5 catalysts with different SiO2/Al2O3 ratios were synthesized, and the effect of acidity over the octane enhancement alongside with desulfurization of heavy naphtha was investigated. In this way, the catalysts with the SiO2/Al2O3 ratios of 20, 40, 60, 80 and 200 were experimentally synthesized and their physical characteristics besides their acidities were measured through X-ray diffraction, the Brunauer–Emmett–Teller and temperature-programmed desorption of ammonia (NH3-TPD) tests. All of them were examined under a specific condition of 5 barg pressure, 450 °C temperature, H2/Oil = 150 ml/Nml, and weight hourly space velocity = 1 h−1 inside a fixed bed reactor. To measure liquid hydrocarbon compositions, analyses of the off-gases, the value of research octane number and the amount of total sulfur of the feed and products were done by means of some tests, including the standard of detailed hydrocarbon analysis, gas chromatography, ASTM D-2699 and ASTM-D5453 utilized, respectively. At SiO2/Al2O3 = 40, the amount of total sulfur went down by 74 wt% and the amount of the Research Octane Number hopefully increased from 51.9 to 93. However, analysis of off-gases stated that despite decreasing the amount of sulfur and increasing the value of octane number in the outlet yields, the ratio of 40 ratio led to by-production of light hydrocarbons, besides 76% liquid yield inevitably. Depending on the results, by using the proposed parallel aromatization–desulfurization process, engineers could bring together the HDS and CRU processes and could diminish the capital and operating costs.