Diesel Yield Research Articles

Thermal cracking of petroleum residue oil using three level factorial design

Thermal cracking of petroleum residue oil was conducted in a high-pressure batch reactor under various operating conditions, temperature in range 400–480°C, reaction time 40–100min and pressure 120–180kPa in the presence of hydrogen. Statistical design of experiment (DOE) was used to evaluate the effect of important variables in the thermal cracking of residue oil, and to obtain the optimum operating conditions. Based on the three level factorial design, quadratic model was developed to correlate the thermal cracking variables to total conversion and linear models for yields of total distillate fuels, gasoline, kerosene and diesel. From the analysis of variance (ANOVA), the most influential factor on each experimental design response was identified. The predicted conversion and yields of total distillate fuels, gasoline, kerosene and diesel were found to agree satisfactorily with the experimental values.

Influence of Nonbasic Nitrogen Compounds and Condensed Aromatics on Coker Gas Oil Catalytic Cracking and Their Characterization

Contrastive fluid catalytic cracking (FCC) performances of coker gas oil (CGO) narrow-boiling fractions before and after HCl aqueous solution and furfural further treatment were investigated. Nonbasic nitrogen compounds and condensed aromatics in test oil samples were identified by negative-ion electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (ESI FT-ICR MS) and gas chromatography and mass spectrometry (GC–MS), respectively. The results show that basic nitrogen compounds mainly retard the feed conversion and liquid products due to their interaction with Brønsted acid sites or Lewis acid sites during catalytic cracking reactions, while the nonbasic nitrogen compounds and condensed aromatics are hard to convert into smaller molecules, just resulting in obvious effects on yields of gasoline and diesel. Moreover, nonbasic nitrogen compounds with single N species are dominant in CGO, identified as carbazoles, cycloalkyl-carbazoles, benzocarbazoles, and cycloalkyl-benzocarbazoles. Condensed aromatics include three to four rings of large dynamic size, usually presented as chrysene, pyrene, and phenanthrene. These compounds deposit on the surface of catalysts and thus redundant coke is formed; consequently, entrances for other hydrocarbons into acid centers are jammed.

Hydrocracking of vacuum gas oil in the presence of supported nickel-tungsten catalysts

The supports containing 70% Al2O3 and 30% β zeolite (AZ-1 and AZ-2), which differed in mixing procedures, and the Ni-W/AZ-1 and Ni-W/AZ-2 catalysts were characterized using an adsorption technique, high-resolution electron microscopy, IR spectroscopy, and X-ray photoelectron spectroscopy and tested in the hydrocracking reaction of vacuum gas oil (VGO). It was found that the supports differed in texture characteristics and surface Lewis acidity at the same composition and similar concentrations of Bronsted acid sites. The formation of Ni-W-S sulfide species on the surfaces of both of the supports occurred in different manners: multilayer Ni-W-S sulfide species were formed on AZ-1 (Ssp = 220 m2/g), whereas single-layer species were mainly formed on AZ-2 (Ssp = 380 m2/g). It was found that catalysts containing multilayer Ni-W-S sulfide species, which were characterized by a higher degree of sulfidation, provided a higher yield of diesel fuel upon the hydrocracking of VGO, whereas catalysts containing single-layer Ni-W-S sulfide species were more active in the reactions of VGO hydrodesulfurization and hydrodenitration.

Modeling and optimization of an industrial hydrocracking unit to improve the yield of diesel or kerosene

Hydrocracking is used in the petroleum industry to convert low-quality feedstocks into highly-valued transportation fuels. This process is the best source of low-sulfur and low-aromatics diesel fuel as well as high-smoke point jet fuel. Many approaches have been proposed for solving optimization of hydrocracking units in the last decades, but they usually neglect the reaction in hydrotreater where hydrocarbon cracking often occurs, thus leading to suboptimal solutions in industrial problems. Unlike existing literature, this paper considers the hydrocarbon cracking reactions in hydrotreater and hydrocracker simultaneously. The models are based on energy balance, mass balance and a discrete lumped model approaches for kinetic modeling. Before optimization, the properties of feedstock are predicted with ASPEN PLUS by using laboratory data from the refinery, and then the model parameters are estimated with genetic algorithm (GA) based on industrial data and validated by comparing the simulating results with industrial data. To improve the yield of the lighter products, the operation conditions are optimized by GA and Sequential Quadratic Programming (SQP). The yields of the diesel or kerosene increase with the proposed approach.

Renewable Diesel Production from the Hydrotreating of Rapeseed Oil with Pt/Zeolite and NiMo/Al2O3 Catalysts

As an alternative way to produce diesel hydrocarbons, the hydrocracking of rapeseed oil was studied on three different types of bifunctional catalysts: Pt/H-Y, Pt/H-ZSM-5, and sulfided NiMo/γ-Al2O3. Experiments were carried out in a batch reactor over a temperature range of 300−400 °C and initial hydrogen pressures from 5 to 11 MPa. The reaction time was limited to 3 h to prevent a high degree of cracking. The Pt-zeolite catalysts had a strong catalytic activity for both cracking and hydrogenation reactions, and therefore a higher severity was required to reach a relatively high oil conversion into liquid hydrocarbons. With dependence on the activity of the acid sites of the catalysts, the results show a trade-off between the yield of green diesel and the degree of isomerization, which had a direct effect on the cold properties of the diesel. Among the three catalysts, hydrocracking on Ni-Mo/γ-Al2O3 gave the highest yield of liquid hydrocarbons in the boiling range of the diesel fraction, i.e., green dies...

Sustainability of algae derived biodiesel: A mass balance approach

A rigorous chemical engineering mass balance/unit operations approach is applied here to bio-diesel from algae mass culture. An equivalent of 50,000,000 gallons per year (0.006002 m3/s) of petroleum-based Number 2 fuel oil (US, diesel for compression-ignition engines, about 0.1% of annual US consumption) from oleaginous algae is the target. Methyl algaeate and ethyl algaeate diesel can according to this analysis conceptually be produced largely in a technologically sustainable way albeit at a lower available diesel yield. About 11 square miles of algae ponds would be needed with optimistic assumptions of 50 g biomass yield per day and m2 pond area. CO2 to foster algae growth should be supplied from a sustainable source such as a biomass-based ethanol production. Reliance on fossil-based CO2 from power plants or fertilizer production renders algae diesel non-sustainable in the long term.

Influence of Asphaltene on the Residue Hydrotreating Reaction

The influence of asphaltene contents on residue hydrotreating was studied in an autoclave. The feedstocks were Tahe deasphalted oil (DAO) mixed with different contents of asphaltene. The changes of asphaltene structure pre- and postreaction were analyzed. The results showed that the conversion of residue was improved by 11% age points when the asphaltene contents increased from 2% to 12%; the yield of gas, coke, gasoline and diesel increased to different degrees, but as the yield of vacuum gas oil (VGO) and >500 °C residue decreased, the removal rate of sulfur and nitrogen first increased and then decreased. The properties of asphaltene were changed after hydroprocessing. It was found that the molecular weight and hydrogen/carbon ratio of asphaltene decreased, the sulfur content decreased but the nitrogen content increased, and the aromaticity and the condensation degree increased. The sulfur and nitrogen contents in the hydrotreated residue increased with asphaltene content as the feedstock increased.

Upgrading of light cycle oil via coupled hydrogenation and ring-opening over NiW/Al 2O 3-USY catalysts

A series of ultrastable Y (USY) zeolite samples with different acidities and pore sizes are prepared via hydrothermal and acid treatments. NiW sulfide catalysts are maintained on a mixed support of USY zeolite and Al 2O 3. The catalytic coupled hydrogenation and ring-opening performance are studied on a continuous fixed-bed reactor using tetralin as the model compound. All catalysts show high tetralin conversions under the reaction conditions studied [ T = 613 K, P = 4.0 MPa, LHSV = 2.0 h −1, H 2/oil (v/v) = 500]. Product yields and selectivity are mainly determined by the zeolite property (i.e., acidity). A medium to strong zeolite acidity is the key factor in the ring-opening selectivity of tetralin. A maximum high cetane ring-opening product yield of 39.1 wt% is obtained at a C 10 yield of 98.2 wt% for a USY zeolite with medium acidity. Using an fluid catalytic cracking light cycle oil feedstock, the activity of the catalyst is higher than that of commercial catalysts, giving a 14-unit cetane number increase at a diesel yield of 97.6 wt%. Because the first step of the ring-opening reaction is hydrogenation, the catalyst must have high hydrogenation activity. The WS 2 slabs have a high average layer number of 2.7 on the catalyst using the support presented here.

Directly Producing Clean and Low Softening Point Diesel Using Integrated Hydrotreating and Hydroisomerizing Catalysts

A novel hydrotreating (HT) catalyst of Mo—W—Ni—P supported on γ-Al 2 O 3 modified by a Group IVA element and a hydroisomerizing (HI) catalyst of W-Ni supported on modified zeolite β with mesopores were prepared by the impregnation method. An integrated process using HT and HI catalysts was designed, and its advantages were well-investigated for directly producing clean diesel from various feedstocks. An industrial application shows that the integrated catalysts have flexible operating modes and are suitable for a wide range of feedstocks. For the HT operating mode, the integrated catalysts showed better hydrodesulfurization (HDS) performance for upgrading the poor quality diesel with a sulfur content of 1000 ppmw and a nitrogen content of 1131 ppmw. The sulfur content of diesel product is less than 40 ppmw, coupled with a hydrodenitrogenation (HDN) rate of 85.76% and an HDS rate of 96.3%. The cetane index increases by 7 units, and the diesel yield is more than 98.0 wt %. For the hydro-dewaxing operating mode, the integrated catalysts showed excellent catalytic performance for upgrading the feeds, with a sulfur content of 990 ppmw and a nitrogen content of 805 ppmw. The HDN rate of 99.42 % and HDS rate of99.99% were also achieved. More importantly, while retaining the cetane index, the diesel yield was as high as 88.72 wt % and the sulfur content and solidifying point of diesel were less than 10 ppmw and -29.3 °C, respectively. The higher HDS and HDN activities of the integrated catalysts are associated primarily with enhanced hydrogenation activity and increased acidity of the HI catalyst.

Ni/W-USY Catalyst for High Diesel Yield and Deep Hydrodearomatization

Two Ni/W hydrodearomatization (HDA) catalysts, CAT-1 and CAT-2, were prepared by wetness impregnation on mixed supports of USY zeolite and amorphous silica−alumina. The structure and properties of CAT-1 and CAT-2 catalysts were characterized by XRD, XRF, pyridine-IR, and N2 adsorption/desorption techniques. The hydrotreating tests with a lower initial boiling point light cycle oil from fluid catalytic cracking showed that CAT-1 catalyst achieved hydrodearomatization, hydrodesulfurization (HDS), and hydrodenitrogenation (HDN) performance: 97.4% hydrodesulfurization, 99.5% hydrodenitrogenation, 14 cetane number improvement, 97.6 wt % diesel yield, and 0.0410 g/cm3 density reduction. The high HDA activity of CAT-1 catalyst was attributed to a low total acidity and Lewis acidity. Adding various modified zeolites did not significantly influence HDS and HDN activities and diesel yield.

Synthesis and characterization of hazelnut oil-based biodiesel

The demand for diesel fuel far exceeds the current and future biodiesel production capabilities of the vegetable oil and animal fat industries. New oilseed crops that do not compete with traditional food crop are needed to meet existing energy demands. Hybrid hazelnut oil is just such an attractive raw material for production of biodiesel. Hazelnut oil was extracted from hybrid hazelnuts and the crude oil was refined. Hazelnut oil-based biodiesel was prepared via the transesterification of the refined hazelnut oil with excess methanol using an alkaline catalyst. The effects of reaction temperature, time and catalyst concentration on the yield of diesel were examined, and selected physical and chemical properties of the biodiesel were evaluated. The biodiesel yield increased with increasing temperature from 25 to 65 °C and with increasing catalyst concentration from 0.1 to 0.7 wt%. The increase in yield with reaction time was nonlinear and characterized by an initial faster rate, followed by a slow rate. Hazelnut oil-based biodiesel had an average viscosity of 8.82 cP at 25 °C, which was slightly higher than that of the commercial soy-based diesel (7.92 cP at 25 °C). An approximate 12 °C higher onset oxidative temperature and a 10 °C lower cloud point of hazelnut oil biodiesel than those of its commercial soy counterpart indicated a better oxidative stability and flowability at low temperature. The average heat of combustion of hazelnut oil biodiesel was 40.23 kJ/g, and accounted for approximately 88% of energy content of diesel fuel. The fatty acid composition of hazelnut oil-based biodiesel was the same as the nature oil.

Change in the properties of diesel fuels in storage in underground tanks

0009-3092/08/4404–0255 © 2008 Springer Science+Business Media, Inc. In Syria, diesel fuels are stored in the north, south (marine), and central regions for 2-5 years. They are made by atmospheric distillation of mixed Syrian crudes consisting of 40 wt. % heavy and 60 wt. % light crudes. The yield of diesel fuel in this mixture is up to 35 wt. %. The initial indexes for the physicochemical properties (their guaranteed limits are shown in parentheses) of diesel fuel stored in an underground tank in the southern region are reported below:

Predicting the Performance of System for the Co-production of Fischer-Tropsch Synthetic Liquid and Power from Coal

A co-production system based on Fischer-Tropsch (FT) synthesis reactor and gas turbine was simulated and analyzed. Syngas from entrained bed coal gasification was used as feedstock of the low-temperature slurry phase Fischer-Tropsch reactor. Raw synthetic liquid produced was fractioned and upgraded to diesel, gasoline, and liquid petrol gas (LPG). Tail gas composed of unconverted syngas and FT light components was fed to the gas turbine. Supplemental fuel (NG, or refinery mine gas) might be necessary, which was dependent on gas turbine capacity, expander through flow capacity, etc. FT yield information was important to the simulation of this co-production system. A correlation model based on Mobil’s two step pilot plant was applied. This model proposed triple chain-length-dependent chain growth factors and set up correlations among reaction temperatures with wax yield, methane yield, and C2–C22 paraffin and olefin yields. Oxygenates in the hydrocarbon, water, and vapor phases were also correlated with methane yield. It was suitable for syngas, iron catalyst, and slurry bed. We can show the effect of temperature on the products’ selectivity and distribution. User models that can predict product yields and cooperate with other units were embedded into Aspen plus simulation. Performance prediction of syngas fired gas turbine was the other key of this system. The increase in mass flow through the turbine affects the match between compressor and turbine operating conditions. The calculation was carried out by GS software developed by Politecnico Di Milano and Princeton University. The simulated performance assumed that the expander operates under choked conditions and turbine inlet temperature equals the NG fired gas turbine. A “F” technology gas turbine was selected to generate power. Various cases were investigated to match the FT synthesis island, power island, and gasification island in co-production systems. Effects of CO2 removal/LPG recovery, co-firing, and CH4 content variation were studied. Simulation results indicated that more than 50% of input energy was converted to electricity and FT products. Total yield of gasoline, diesel, and LPG was 136–155g∕Nm3(CO+H2). At coal feed of 21.9kg∕s, net electricity exported to the grid was higher than 100MW. Total production of diesel and gasoline (and LPG) was 118,000t(134,000t)∕year. Under the economic analysis conditions assumed in this paper, the co-production system was economically feasible. The after tax profits can research 17 million euro. Payback times ranged from 6 to 7 years.

Reduction of NO x in diesel engine emissions by using a plasmatron fuel reformer

An experimental study of diesel exhaust cleaning by means of the plasma chemical pretreatment of fuel is described. Some portion of the fuel was activated in an arc discharge and turned into hydrogen-rich synthesis gas. Plasma chemical reformation of fuel was carried out by using a DC arc plasmatron that was fabricated to increase the ability of gas activation. The yield of diesel fuel reformation reached about 80−100% when small quantities of fuel (flow rate up to ∼6 ml/min) were reformed. The synthesis gas, containing H2+CO, was supplied into the engine together with the rest of the fuel-air mixture, and the NOx content in its emissions reduced up to 23%.

Physical and Chemical Characterization of Petroleum Products by GC-MS

There is a need for reliable and fast means of monitoring refining, conversion, and upgrading processes aiming to increase the yield of light distillates, and thus, reducing the oil barrel bottoms. By simultaneously utilizing the FID and mass selective detectors while splitting the column effluent in a controlled way, it is possible to obtain identical gas chromatograms and total ion chromatograms from a single run. This means that besides the intensity vs. time graphs, the intensity vs. mass and boiling point can also be obtained. As a result, physical and chemical characterization can be performed in a simple and rapid manner. Experimental results on middle, heavy distillates, and crude oil fractions show clearly the effect of upgrading processes on the chemical composition and yields of diesel, jet fuels, and high vacuum gasoil fractions. The methodology is fully compliant with ASTM D-2887, D-7213, D-6352, and D7169 for simulated distillation and the previously mentioned mass spectrometry standards. The group type analysis correlated satisfactorily with high-performance liquid chromatography data.

Performance-focused Catalyst Design to Meet Diesel Quality Improvements—Part II

In this work, we present an experimental evaluation concerning the catalytic hydrocracking of gas oil (GO) feedstock. The study was carried out using five types of supported NiMo-based catalysts (100A, 100AP, 100AB, 100H-DY, and 30H-DY). Screening tests of the performance of these sulfided catalysts were carried out in a high-pressure batch autoclave at temperatures of 350°C–425°C, reaction time of 1–3 hr, catalyst/feed ratios of 5–10%, and initial hydrogen pressure of 6.0 MPa. This study clearly shows that the incorporation of H-DY zolite into aluminum borate (AB) matrix led to a greatly improved hydrocracking catalyst for production of lighter products, in addition to depressing the pour point of the diesel fuel product. In all experiments, the yield of gasoline and gaseous products increased dramatically by increasing the severity of the process variables. A high-pressure test unit was used to study the effect of different process variables as pressure (3.0–6.0 MPa), liquid hourly space velocity (1.5–3 hr−1), hydrogen/ GO volumetric ratio (400 vol./vol.), and temperatures of 375°C, on the GO conversion to various products using 30H-DY catalyst, and to correlate the impact of process conditions on the yield and quality of diesel fuel and gasoline products to optimize the process

Hydrocracking of heavy oil using zeolites Y/Al-SBA-15 composites as catalyst supports

A series of Y/Al-SBA-15 composites were prepared by a two-step synthesis procedure in mild acidic medium. The materials were characterized by powder X-ray diffraction (XRD), N2 sorption isotherms and TEM techniques. Catalytic cracking of cumene and 1,3,5-tri-isopropylbenzene was carried out as the probing reactions on these composites. The XRD results showed that these materials are composites of Al-SBA-15 and Y zeolite. N2 sorption isotherms and TEM displayed that these composites were abundant in micropores and mesopores. At the same time, the mesopores may communicate with the␣micropores in some domains, which may result in the high catalytic activities of Y/Al-SBA-15 composites for the␣cracking of both small-molecule (cumene) and large-molecule (1,3,5-tri-isopropylbenzene) hydrocarbons. The existence of mesopores may also make the acid sites easily accessible for reactants. Catalysts of W–Ni supported on Y/Al-SBA-15 and modified Y zeolites with mesopores were prepared by impregnation method, and the hydrocracking of heavy oil was performed on these catalysts. The catalyst using zeolite Y/mesoporous Al-SBA-15 composites as support gave higher yield of diesel compared to the catalysts using modified zeolite Y as support. In addition, the higher aromatics potential of heavy naphtha and the significantly lower BMCI (U.S. Bureau of Correlation Index) of tail oil revealed Y/Al-SBA-15 composite catalyst possessed integrated performance in the hydrocracking of heavy oil. These results proved that the combination of Y zeolites and mesoporous Al-SBA-15 plays a great role in improving the performance of catalysts for hydrocracking heavy oils.

Study on Non-Hydrogenation Refining for RFCC Diesel

Using an FS chemical refining agent can improve the stored stability of RFCC diesel. After being stored for 3 months, colority of refined diesel was 3.0, oxidized total insolubles was 1.9 mg/100 mL, acidity was only 1.6 mg KOH/100 mL, and mercaptan sulfur content was obviously decreasing. The aforementioned data met the criteria of GB252-2000. Yield of diesel has reached 99.8%. Processing cost was just ¥25/t, which fits conditions in China.

Long-term evaluation of NiMo/alumina–carbon black composite catalysts in hydroconversion of Mexican 538 °C+ vacuum residue

Alumina with (8–18 wt.%) carbon black composite (AMAC) supports was prepared as bimodal extrudates, containing 11–20% of total pore volume as macropores (i.e. >1000 Å). These supports, in spite of containing carbon black and macropores, showed good side crushing strength (0.67–1.19 kg/mm) after pyrolysis in 6% O 2/N 2. AMAC-catalysts were obtained after impregnating these alumina–carbon black supports with Ni and Mo, to obtain 3.5 wt.% NiO and 15 wt.% MoO 3. These catalysts were evaluated for about 700 h in the hydroconversion of a Mexican vacuum residue (538 °C+) at 415 °C, 200 kg/cm 2, H 2/HC = 6000 ft 3/barrel in a pilot plant equipped with a Robinson–Mahoney reactor. In comparison with a commercial bimodal alumina-based catalyst (ComCat), AMAC catalysts showed much fewer sediments and less Conradson carbon formation. Initial HDS in AMAC containing macropores can be as high as 92%, while that in a ComCat is 86%. On average, yields of naphtha and kerosene were 2.6 and 1.34 times higher with AMAC catalysts than those with ComCat, while diesel yields were similar.

Hydrocracking of Iron-Catalyzed Fischer−Tropsch Waxes

Sasol iron-catalyzed Fischer−Tropsch (FT) reactor waxes were hydrocracked at 3.5 and 7.0 MPa hydrogen pressure to fuels using a NiMo on SiO2/Al2O3 catalyst. The aim was to predominantly produce diesel. The effects of feed carbon number distribution, reaction variables, and process configurations have been investigated. High hydrogen-to-wax ratios led to improved C23+ conversion and increased diesel yields. Increasing the liquid hourly space velocities decreased C23+ conversion and increased diesel selectivity. Prehydrogenation of FT reactor wax prior to the hydrocracking reaction improved C23+ conversion; however, it negatively influenced diesel selectivity. The apparent n-paraffin reactivity was found to be chain length dependent increasing with pressure.