Distillation End Point Research Articles

Process for producing high octane gasoline having lower benzene content and distillation end point with its environmental effect of engine exhaust emissions

In this research, a process is discussed for upgrading reformate and power former in Iraq’s Al-Doura refinery, by reducing the amount of benzene in the gasoline product with simultaneous reduction in the gasoline’s ASTM distillation end point. The process consists of fractionation of the reformate and power former to recover that fraction (90–180°C) of hydrocarbons. This was directly used as gasoline without further conversion. The heavy bottom fraction (180°C—EBP) consisting of the aromatic and non-aromatic hydrocarbons was recovered and used as antiknock additives to gasoline. The other fraction with (IBP—90°C) was used as feedstock to producing benzene by solvent extraction. The reformate and power former fractions (90–180°C) are blended with light straight run naphtha at ratio (75: 25) to producing gasoline as well as Al Doura gasoline. It was found that the amount of benzene was reduced from 1.41 wt % in the original pool to 1.37 and 1.31 in the alternative products. Engine emissions were also reduced when using the alternative products compared with original pool product.

Effect of oxidation and extent of oxidation on biologically active PACs in asphalt products

Recent studies have reported divergent results in rodent cancer assays using fume condensates from a variety of asphalt products. This paper presents results of a study investigating the role of oxidation, or extent of oxidation, on these findings. Five straight run asphalts, made from widely used crude oils, were used as inputs to both production scale and laboratory oxidation units and processed to a range of softening points used in common roofing products. For each of the five asphalts studied, the oxidation reaction significantly decreased measures of polycyclic aromatic compounds (PACs) that have been linked, previously and in analyses included in this study, to tumor induction in rodent bioassays. Mutagenicity index determined by the modified Ames assay was reduced between 41% and 50% from the input asphalt to the final oxidized product. A fluorescence method tuned to a subset of PAC compounds that have been associated with carcinogenic behavior in mouse bioassays was reduced between 39% and 71%. The decrease was largest in the first quarter of the oxidation reaction. These findings indicate that oxidation, by itself, was not a likely factor in the tumor induction seen in the previous studies. Rather, other factors such as the conditions of fume generation and crude source (coupled with possible differences in distillation endpoints) were more likely to have determined the outcomes. Analyses of previously published data, presented in this paper, suggest that the modified Ames and fluorescence assays are valuable screening tools for use in future health-related asphalt research.

Development of Soft Sensors for Crude Distillation Unit Control

AbstractSoft sensors for distillation end point (D95) on-line estimation in crude distillation unit (CDU) are developed. Experimental data are acquired from the refinery distributed control system (DCS) and include on-line available continuously measured variables and laboratory assays. Soft sensors are developed using different linear and nonlinear identification methods. Additional laboratory data for model identification are generated by Multivariate Adaptive Regression Splines (MARSplines). The models are evaluated based on Route Mean Square (RMS), Absolute Error (AE), FIT and Final Prediction Error (FPE) criteria. The best results are achieved with Box Jenkins (BJ), Output Error (OE) and Hammerstein–Wiener (HW) model. Based on developed soft sensors it is possible to estimate fuel properties in continuous manner and apply inferential control. By real plant application of developed soft sensors considerable savings could be expected, as well as compliance with strict law regulations for product quality specifications.

Comprehensive two-dimensional gas chromatography for basic and neutral nitrogen speciation in middle distillates

The molecular knowledge of nitrogen compounds in diesel feedstocks has become a key issue in the development of hydrotreatment processes, especially for ultra-low sulfur diesel production. Indeed, nitrogen species have a strong impact on the hydrodesulfurization (HDS) pathway, since basic nitrogen is known to poison acidic sites of HDS catalysts. Since conventional methods only allow a poor degree of information, the increased separation power of comprehensive two-dimensional gas chromatography (GC × GC-NCD) was used in this study to obtain a detailed overview of nitrogen compounds by type (basic/neutral), by family and by carbon breakdown in diesel and liquefied coal samples. Partially hydrogenated compounds such as tetrahydrocarbazole and tetrahydroquinoline derivatives could even be detected in liquefied coal samples as well as diesel from ebullated bed conversion units. Comparison of GC-NCD with GC × GC-NCD for quantitative determination of nitrogen compounds by family was achieved in a first step. These results demonstrate the superiority of GC × GC to allow for a comprehensive characterization of nitrogen compounds in diesel and related samples in one injection. Furthermore, nitrogen speciation by GC × GC-NCD technique allows identifying most nitrogen species in conventional diesel or liquefied coal samples, with no use of mass spectrometry. GC × GC-NCD was also applied to a wide range of diesel feedstocks obtained from distillation, cokefaction, FCC, ebullated bed hydroconversion units to correlate nitrogen species to the origin of the feedstocks or distillation end points, giving interesting indications on reaction mechanisms involved in the processes.

98/01961 A lumping kinetics for modified FT reforming process. II. Experimental and kinetics parameters estimation : Liu, Z.-W. et al. J. Nat. Gas Chem., 1997, 6, (4), 313–321

Environmentally driven regulations are requiring continuous and significant changes in diesel fuel quality in many parts of the world. Further tightening of specifications are being considered for the future, with trends to lower density, sulphur, and distillation end point, as well as higher cetane number, to meet with more stringent levels of new motor power and environmental regulations.Hydroprocessing is extensively practised in petroleum industry to upgrade fuels refinery streams. In this paper, pilot plant data is presented of a moderate pressure technology developed to produce diesel fuel comply with actual and near future environmental regulations using feedstocks since medium to high contaminants content. This technology is based on Co-Mo and Ni-Mo γ-alumina supported proprietary catalysts, with high activity to sulphur and aromatics compounds commonly encountered in these petroleum fractions. Discussion will be driven to show the effect of process conditions on product quality and mains difference in catalysts performance. A series of Isthmus/Maya crude oils mixtures was prepared to test catalyst efficiency, but for the sake of explicitness, only three of these are reported in this work. Hydrodesulphurisation and hydrodenitrogenation activities are quite similar in both catalysts, but aromatic saturation is much more effective in Ni-Mo version. This fact is important when domestic refineries make more intensive use of light cycle oil as a mix component in the feedstock to fulfil demand.

98/00178 Preparing and handling coal-water slurry fuels: potential problems and solutions

Environmentally driven regulations are requiring continuous and significant changes in diesel fuel quality in many parts of the world. Further tightening of specifications are being considered for the future, with trends to lower density, sulphur, and distillation end point, as well as higher cetane number, to meet with more stringent levels of new motor power and environmental regulations.Hydroprocessing is extensively practised in petroleum industry to upgrade fuels refinery streams. In this paper, pilot plant data is presented of a moderate pressure technology developed to produce diesel fuel comply with actual and near future environmental regulations using feedstocks since medium to high contaminants content. This technology is based on Co-Mo and Ni-Mo γ-alumina supported proprietary catalysts, with high activity to sulphur and aromatics compounds commonly encountered in these petroleum fractions. Discussion will be driven to show the effect of process conditions on product quality and mains difference in catalysts performance. A series of Isthmus/Maya crude oils mixtures was prepared to test catalyst efficiency, but for the sake of explicitness, only three of these are reported in this work. Hydrodesulphurisation and hydrodenitrogenation activities are quite similar in both catalysts, but aromatic saturation is much more effective in Ni-Mo version. This fact is important when domestic refineries make more intensive use of light cycle oil as a mix component in the feedstock to fulfil demand.

The use of a radioactive tracer for the determination of distillation end point in a coke oven

A novel high precision detection method for the determination of the distillation end point of the coking process (usually in the 950–1100°C range) has been developed. The system is based on the use of a metallic capsule that melts at a fixed temperature and releases a radioactive gas tracer (133Xe) in the stream of the distillation gas. A series of tests on a pilot oven confirmed the feasibility of the method on industrial scale. Application of the radioactive tracer method to the staging and monitoring in the coking process appears to be possible.

Hydrotreating the bitumen-derived hydrocarbon liquid produced in a fluidized-bed pyrolysis reactor

The pyrolysis of bitumen-impregnated sandstone produces three primary product streams: C 1C 4 hydrocarbon gases, a C 5 + total liquid product, and a carbonaceous residue on the spent sand. The bitumen-derived hydrocarbon liquid was significantly upgraded relative to the native bitumen: it had a higher API gravity, lower Conradson carbon residue, asphaltene content, pour point and viscosity, and a reduced distillation endpoint relative to the native bitumen. The elemental composition was little different from that of the native bitumen except for the hydrogen content, which was lower. Thus, integration of the bitumen-derived liquid into a refinery feedstock slate would require that it be hydrotreated to reduce the nitrogen and sulphur heteratom concentrations and to raise the atomic hydrogen-to-carbon ratio. The bitumen-derived liquid produced in a fluidized-bed reactor (diameter 10.2 cm) from the Whiterocks tar sand deposit has been hydrotreated in a fixed-bed reactor to determine the extent of upgrading as a function of process operating variables. The process variables investigated included total reactor pressure (11.0–17.2 MPa (1600–2500 psig)); reactor temperature (617–680 K; (650–765 °F)) and liquid hourly space velocity (0.18-0.77 h −1). The hydrogen/oil ratio was fixed in all experiments at 890 m 3 m −3 (5000 scf H 2/bbl). A sulphided Ni-Mo on alumina hydrodenitrogenation catalyst was used in these studies. The extent of denitrogenation and desulphurization of the bitumen-derived liquid was used to monitor catalyst activity as a function of process operating variables and to estimate the extent of catalyst deactivation as a function of time on-stream. The apparent kinetics for the nitrogen and sulphur removal reactions were determined. Product distribution and yield data were also obtained.

Paraffins, olefins, naphthenes and aromatics analysis of selected hydrocarbon distillates using on-line column switching high-performance liquid chromatography with dielectric constant detection

A novel analytical method is introduced that measures the volume fraction of paraffins, olefins, naphthenes, and aromatics (PONA) in hydrocarbon liquids having distillation endpoints (American Society for Testing and Materials, ASTM D 2887) of at least 300°C. The method uses on-line column switching high-performance liquid chromatography (HPLC) with dielectric constant detection (DCD), i.e., HPLC-DCD. A specially configured hydrocarbon group-type analyzer system is used. The PONA separations are achieved using an olefin-selective column, an unsaturate-selective column, three naphthene-selective columns, two six-port switching valves, and Envron 123 as the mobile phase. The HPLC-DCD system ensures a genuine uniformity of response (less than 2.5% relative standard deviation) independent of the carbon number distribution of the sample or the group type. Unity response factors are sufficient for accurate quantitation. On the basis of complex solutions of hydrocarbon standards, the accuracy for each structural group type is within 2% absolute. The chromatographic limit of detection of the present system for naphthenes is less than 4.0 vol.% ( ca. 40 μg), for a kerosene fuel containing a wide carbon number distribution of both mono- and di-cycloparaffins, and is approximately 1.0 vol.% ( ca. 10 μg) for olefins. Sample turnaround time is approximately one hour. The results of the PONA analysis scheme are compared to those of the standard fluorescent indicator adsorption (FIA) liquid displacement method (ASTM D 1319), an alternative to the FIA method developed in this laboratory using HPLC-DCD, and a mass spectrometric method (ASTM D 2789) on standard mixtures and real-world products. For determining total naphthenes and olefins in the gasolines and kerosenes selected for study, the HPLC-DCD system was superior.

Rapid determination of naphthenes in hydrocarbon distillates using on-line column switching high-performance liquid chromatography with dielectric constant detection

On-line column switching high-performance liquid chromatography (HPLC) with dielectric constant detection (DCD) can separate and accurately quantify the volume fraction of total cycloparaffins in gasolines and kerosenes having distillation endpoints (ASTM D 2887) of at least 300°C. The three hydrocarbon group-types reported are: acyclic paraffins, cycloparaffins, and unsaturates, i.e., aromatics plus olefins. The HPLC—DCD separations are achieved using an “unsaturate-selective” column, two “naphthenic-selective” columns, two six-port switching valves, and Freon 123 as the mobile phase. Incorporation of one or two additional naphthenic-selective columns could extend the range of samples that can be analyzed to include diesel fuels. The dielectric constant detector ensures a genuine uniformity of response [relative standard deviation < 2.5%] for each hydrocarbon group type independent of the carbon number distribution of the sample. Unity response factors are sufficient for accurate quantitation. On the basis of complex solutions of hydrocarbon standards, the accuracy for each structural group type is within two percent absolute. The chromatographic limit of detection for naphthenes is less than 4.0 vol. % ( ca.40 μg) for a kerosene fuel containing a wide carbon number distribution of both mono- and di-cycloparaffins. Sample turnaround time is approximately 40 min.

Hydrocarbon group type analyzer system for the rapid determination of saturates, olefins, and aromatics in hydrocarbon distillate products

A dielectric constant (DC) detector for high-performance liquid chromatography (HPLC) is the basis of a rapid and accurate hydrocarbon group type analysis. This novel method can determine saturates, olefins, and total aromatics in hydrocarbon liquids with distillation end points (ASTM D 2887) of at least 400 /sup 0/C. The HPLC separation is achieved by using a single, olefin-selective column, a backflush valve, and Freon 123 as the mobile phase. The DC detector ensures a genuine uniformity of response (less than 2.5% relative standard deviation) for each hydrocarbon group type independent of the carbon number distribution of the sample. Unity response factors are sufficient. On the basis of complex solutions of hydrocarbon standards, the accuracy for each structural group type is within 1% absolute. The chromatographic limit of detection is less than 0.5 vol % (800 ng) for the last eluting hydrocarbon group, i.e., the olefins.

Fuel Character Effects on J79 and F101 Engine Combustor Emissions

Results of a program to determine the effects of fuel properties on the pollutant emissions of two US Air Force aircraft gas turbine engines are presented. Thirteen test fuels, including baseline JP-4 and JP-8, were evaluated in a cannular (J79) and a full annular (F101) combustor. The principal fuel variables were hydrogen content, aromatic structure, volatility, and distillation end point. Data analysis shows that fuel hydrogen content is a key fuel property, particularly with respect to high power emissions (oxides of nitrogen and smoke), and that low power emissions (carbon monoxide and hydrocarbons) are more dependent on fuel atomization and evaporation characteristics.© 1980 ASME

Fuel Property Effects on Life Characteristics of Aircraft Turbine Engine Combustors

Results of a program to determine the effects of fuel properties on the life characteristics of two USAF/General Electric aircraft turbine engine combustors are presented. Thirteen test fuels were evaluated in an older technology cannular combustion system (J79) and in an advanced-technology, virtually smokeless, compact, annular combustion system (F101) over wide ranges of simulated engine operating conditions. Fuel variables were hydrogen content, aromatic structure, volatility, and distillation end point. Significant increases in combustor liner temperatures were observed as fuel hydrogen content was decreased. With fuel hydrogen contents of 14.5,14.0,13.0, and 12.0, the resulting relative combustor liner cyclic life predictions are 1.00, 0.78, 0.52, and 0.35 for the J79 combustor and 1.00, 0.72, 0.52, and 0.47 for the F101 combustor, respectively. Based upon these findings, it is concluded that improved liner cooling design features will be needed in most currenttechnology combustors to accommodate the projected lower hydrogen contents of future fuels.