Diesel Yield Research Articles

Simultaneous Optimization and Heat Integration for the Coproduction of Diesel Substitutes: Biodiesel (FAME and FAEE) and Glycerol Ethers from Algae Oil

In this paper, an optimal process for the simultaneous production of biodiesel (using methanol or bioethanol) and ethers of glycerol is proposed to increase the yield to diesel substitutes in current biodiesel production facilities. The problem is formulated as an optimization model including algae oil production, production of ethanol from starch, transesterification of the oil with bioethanol or methanol, etherification of glycerol with i-butene, which depends on a dynamic model to compute the complex chemical kinetics, and the purification of the ethers. Simultaneous optimization and heat integration are carried out and finally the water consumption of the integrated processes is optimized. Several comparisons are presented. First, the use of glycerol to produce ethers or as a byproduct. Second, the use of different alcohols for biodiesel synthesis in an integrated process. The production of glycerol ethers increases the yield of diesel substitutes by 20%. Furthermore, the energy and water consumptions are competitive with those processes when glycerol is the byproduct. For the integration of glycerol ethers with current biodiesel plants, the use of methanol instead of ethanol is cheaper. However, the current price of i-butene results in high production costs. Simultaneous production of ethanol, biodiesel and glyerol ethers reaches the target of $1/gal for biofuels production cost.

The effects of magnesium of Zn–Mg–Al additives on catalytic cracking of VGO and in situ reduction of sulfur in gasoline

The scope of the present study is to describe the cracking behavior of hydrocarbons and the reduction of sulfur in gasoline in fluid catalytic cracking (FCC) process using Zn–Mg–Al additives with varying the Mg/Al molar ratios. Experiments have been carried out on a micro-activity-test (MAT) reactor using high-sulfur vacuum gas oil (VGO) feed and zinc impregnated Mg–Al spinels as additive and the commercial cracking catalyst. It was found that Zn–Mg–Al additives exhibited enhanced Lewis acidity compared with the corresponding Zn-free Mg–Al spinels. The MAT results indicated that the addition of additives reduced the yields of liquid petroleum gas and coke at low Mg contents but increased the coke yield at high Mg contents. Overall, the additives improved the yields of gasoline and diesel. It has also been shown that the rich Lewis acidity had a positive effect on the conversion of aromatic sulfur species of gasoline and the maximum reduction of gasoline sulfur was achieved with Zn/Mg4.0Al2O3 due to the synergistic effect of basicity and Lewis acidity.

Peptization Mechanism of Boehmite and Its Effect on the Preparation of a Fluid Catalytic Cracking Catalyst

A peptization mechanism of boehmite was proposed in this work. The effects of peptization on the properties and performances of a fluid catalytic cracking (FCC) catalyst were explored. A boehmite colloid was prepared through peptization of boehmite with hydrochloric acid, and its particle size distribution was characterized during peptization. With an increase of the acid/alumina molar ratio from 0 to 0.11, the particle size of the boehmite colloid decreased to 3.5 nm. The particle size increased from 3.5 to 11 nm when the acid/alumina molar ratio was further increased to 0.16 and remained at 10 nm thereafter. The smallest dispersed boehmite particles were obtained in an acid/alumina molar ratio of 0.11. On the basis of many experiments, the dispersion and coalition mechanisms of boehmite during acid peptization were proposed. Boehmite particles absorb protons on the surface hydroxyl groups and repel each other to form colloidal particles when the acid/aluminia ratio is low. With more hydrochloric acid added, large amounts of chloride anions cause compression of the boehmite diffuse layer, thus resulting in boehmite coalition. A FCC catalyst was prepared by peptizing boehmite with an acid/alumina molar ratio of 0.11. The catalyst has a larger external surface area, a higher mesoporous volume, and better acidity distribution than the catalyst prepared with boehmite. Both conversion of residue oil and yields of diesel and gasoline over a peptized catalyst are higher than those over the catalyst without being peptized.

Effectiveness of CoMo and NiMo catalysts on co-hydroprocessing of heavy atmospheric gas oil–waste cooking oil mixtures

Co-hydroprocessing of fossil fractions with lipids is an alternative pathway for integrating biomass in the transportation sector. This work involves the evaluation of two commercial hydrodesulfurization (HDS) catalysts in terms of their effectiveness and suitability for hydroconversion of heavy atmospheric gas oil (HAGO) and waste cooking oil (WCO) mixtures. As the most common catalysts for conventional gas oil hydroprocessing are CoMo and NiMo over Al2O3, this work focused on comparing a CoMo/Al2O3 and a NiMo/Al2O3 catalyst with respect to the resulting diesel selectivity and quality. Both catalysts were investigated for three feedstocks including pure HAGO, a low WCO content (10% v/v) HAGO/WCO and a higher WCO content (30% v/v) HAGO/WCO mixture under three different reactor temperatures (330°C, 350°C and 370°C). All the experiments were performed at constant pressure 812psig, liquid hourly space velocity (LHSV) 1h−1 and H2/Oil ratio 505.9nl/l. The results have shown that the catalyst HDS efficiency depends primarily upon the reaction temperature and HAGO to WCO ratio, but is quite different for both catalyst types. The HDS effectiveness of the NiMo catalyst is not affected by the addition of WCO, even in the lowest temperature (330°C), while the one of the CoMo catalyst is strongly affected by WCO. The presence of WCO in the feedstock was proven favorable for both diesel yield and saturation, for both catalysts, but affected strongly the deactivation rate of the CoMo catalyst. Based on the experimental results obtained via this study, it was evident that NiMo type catalysts are more suitable for co-hydroprocessing of petroleum fractions with lipid containing feedstocks.

Development of technology for producing bio-jet fuel from several feedstocks

To reduce the emission of greenhouse gases and broade the raw material sources of jet fuel, many countries have accelerated the development of bio-jet fuel. The technology for producing bio-jet fuel by hydrotreating vegetable oils or animal fat has been developed by SINOPEC, which contains different processing routes to produce bio-jet fuel and bio-diesel to meet the market demands, such as the route of producing bio-jet fuel maximally, and the route of producing bio-jet fuel and bio-diesel at one time. Relative to vegetable oil or animal fat, the final yield of bio-jet fuel with freezing point lower than -48 ℃ can reach to 35%-45%, the yield of diesel is 7%-11%, and the yield of naphtha is 23%-29%. The bio-jet fuel product fitting for the standard of ASTM D7566-11 has been produced by SINOPEC in an industrial unit, which was successful in the flight-test.

Comparison of Kinetic-based and Artificial Neural Network Modeling Methods for a Pilot Scale Vacuum Gas Oil Hydrocracking Reactor

An artificial neural network (ANN) and kinetic-based models for a pilot scale vacuum gas oil (VGO) hydrocracking plant are presented in this paper. Reported experimental data in the literature were used to develop, train, and check these models. The proposed models are capable of predicting the yield of all main hydrocracking products including dry gas, light naphtha, heavy naphtha, kerosene, diesel, and unconverted VGO (residue). Results showed that kinetic-based and artificial neural models have specific capabilities to predict yield of hydrocracking products. The former is able to accurately predict the yield of lighter products, i.e. light naphtha, heavy naphtha and kerosene. However, ANN model is capable of predicting yields of diesel and residue with higher precision. The comparison shows that the ANN model is superior to the kinetic-base models. © 2013 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0)

A Study on the Aromatization Reaction of Lanlian FCC Gasoline

By using Lanlian catalytic gasoline as a feedstock, the effects of reaction temperature, weight hourly space velocity, and catalyst to oil on the aromatization product yield, conversion, motor octane number, research octane number, and liquid product compound were researched in a confined fluidized bed reactor. The experimental result showed the yields of off-gas, liquefied petroleum gas (LPG), and coke increase with the increase of the reaction temperature. But the yield of gasoline and diesel decrease with the increase of the reaction temperature. The yields of off-gas, LPG, and coke gradually decrease with the increase of weight hourly space velocity. But the yields of gasoline and diesel increase with the increase of weight hourly space velocity. The yields of off-gas, LPG, and coke increase with the increase of the catalyst to oil. But the yields of gasoline and diesel slowly decrease with the increase of the catalyst to oil. The best operation condition will be confined: reaction temperature, weight hourly space velocity, and catalyst to oil are between 430 and 450°C, between 20 and 30 h−1, between 6 and 12. The gasoline, diesel oil, and the aromatics contents of liquid production before entering gasoline and after entering liquefied petroleum gas are higher than these simultaneously entering gasoline and liquefied petroleum gas and before entering liquefied petroleum gas and after entering gasoline.

Composition of stacked bed for VGO hydrocracking with maximum diesel yield

Hydrocracking catalysts prepared by co-impregnation of three different supports with solutions containing Ni, Mo and citric acid were studied. Pure γ-Al2O3, 30% of zeolite Y/γ-Al2O3 and 70% of amorphous aluminosilicate ASA (Si/Al=0.9)/γ-Al2O3 were used as supports. All the catalysts were shown to contain the particles of Ni-Mo-S phase with similar morphology after liquid phase sulfidation by DMDS. The active component is uniformly distributed on γ-Al2O3 and ASA surface in NiMo/Al2O3 and NiMo/ASA-Al2O3 catalysts. The main amount of Ni and Mo is localized on γ-Al2O3 surface in NiMo/Y-Al2O3 catalyst while the main part of zeolite Y surface is free of supported metals. Testing of stacked beds, which comprise different prepared catalysts, in hydrocracking of vacuum gasoil showed that the NiMo/Al2O3 catalyst had the maximum selectivity to diesel fuel, but its activity was insufficient. Diesel fuel yield did not exceed 50wt.% for the stacked beds comprising NiMo/Y-Al2O3 independent on the process temperature. NiMo/ASA-Al2O3 had an optimal ratio of activity to selectivity for the production of diesel fuel and provided the diesel fuel yield by over 60wt.% at 400°C.

Diesel-like hydrocarbon production from hydroprocessing of relevant refining palm oil

This paper demonstrates the initiated use of relevant refining palm oil for bio-hydrogenated diesel production. The conversions of crude palm oil (CPO) and its physical refining including degummed palm oil (DPO) and palm fatty acid distillate (PFAD) to diesel fuel by hydroprocessing were studied. The effects of operating parameters (i.e. reaction time, operating temperature, and pressure) and catalyst (i.e. Pd/C and NiMo/γ-Al2O3) were examined in order to determine suitable operating condition for each feedstock. It was found that the hydroprocessing of CPO with Pd/C catalyst at 400°C, 40bar, and reaction time of 3h provides the highest diesel yield of 51%. When gum which contains phospholipid compounds is removed from CPO, namely DPO, the highest diesel yield of 70% can be obtained at a shorter reaction time (1h). In the case of PFAD, which consists mainly of free fatty acids, a maximum diesel yield of 81% could be observed at milder conditions (375°C with the reaction time of 0.5h). The main liquid products are n-pentadecane and n-heptadecane, having one carbon atom shorter than the corresponding fatty acids according to decarboxylation/decarbonylation pathways. Pd/C catalyst shows good catalytic activity for fatty acid feedstocks but becomes less promising for triglyceride feedstocks when compared to NiMo/γ-Al2O3.

Coking Reactivity of Laboratory-Scale Unit for Two Heavy Petroleum and Their Supercritical Fluid Extraction Subfractions

The building of a separation-reaction network for heavy feedstock requires an understanding of the reactivity for subfractions. This paper proposes a study on the coking reactivity for two heavy petroleum samples, vacuum residua (VR) from China Liaohe and Venezuela Orinoco crude oils, and their supercritical fluid extraction fractionation (SFEF) subfractions. The properties of feedstocks and their SFEF series were analyzed, including density, molecular weight, elemental content, Conradson carbon residue (CCR), SARA components (saturates, aromatics, resins and asphaltenes) and structure parameters by nuclear magnetic resonance (NMR). All the samples were subjected to a laboratory-scale batch reactor to investigate the coking reactivity. Coke yield increased as the SFEF subfraction became heavier; while the yields of naphtha, diesel, and gas oil all decreased. The results show that the classic linear correlation between coke yield and CCR are not appropriate for separated fractions of VR. Instead, a negative power function was observed. Furthermore, the coke yield shows a linear relationship with aromaticity for both SFEF series. To precisely estimate coking reactivity for feedstocks and subfractions, a new SARA component based prediction model was carried out, which reveals the contribution of each component.

Preparation, Characterization, Evaluation, and Regeneration of a Novel Hydro-upgrading Catalyst

A non–noble metal hydro-upgrading catalyst was prepared using modified zeolites as acidic component, and catalytic performance evaluation was also carried out between the hydro-upgrading catalyst and the reference catalyst, which is a commercial catalyst. The evaluation results revealed that under the pressure of 8.0 MPa, the diesel product yield of the hydro-upgrading catalyst was 98.8 m%, cetane index increment was 7.3 units, diesel yield of the reference catalyst was 98.3 m%, and the cetane index increment was 7.2 units; under the pressure of 6.0 MPa, the diesel product yield of the hydro-upgrading catalyst was 99.1 m%, cetane index increment was 6.1 units, diesel yield of the reference catalyst was 98.7m%, and the cetane index increment was 5.3 units. In addition, preparation repeatability, activity stability, and regeneration performance tests of the hydro-upgrading catalyst were carried out.

Synthesis of renewable diesel with hydroxyacetone and 2-methyl-furan

Diesel or jet fuel range branched alkanes were synthesized for the first time by the combination of hydroxyalkylation-alkylation (HAA) of 2-methylfuran with hydroxyacetone and subsequent hydrodeoxygenation. Due to the electron-withdrawing effect of the hydroxyl group, the hydroxyacetone route exhibited evident advantages (higher HAA reactivity and diesel yield) over the previous acetone route.

Multifunctional Two-Stage Riser Catalytic Cracking of Heavy Oil

The continuous deterioration of feedstocks, the increasing demand of diesel, and the increasingly strict environmental regulations on gasoline call for the development of fluid catalytic cracking (FCC) technology. To increase the feed conversion and the diesel yield as well as produce low-olefin gasoline, the multifunctional two-stage riser (MFT) FCC process was proposed. Experiments were carried out in a pilot-scale riser FCC apparatus. Results show that a higher reaction temperature is appropriate for heavy cycle oil (HCO) conversion, and the semispent catalyst can also be used to upgrade light FCC gasoline (LCG). The synergistic process of cracking HCO and upgrading LCG in the second-stage riser can significantly enhance the conversion of HCO while reducing the olefin content of gasoline at less expense of gasoline yield. Furthermore, the novel structure riser reactor can increase the conversion of olefins in gasoline. Because of the significant increase of HCO conversion, the fresh feedstock can be cr...

Slurry-phase hydrocracking of vacuum residue with a disposable red mud catalyst

In this study, red mud (RM) was used as a catalyst in slurry-phase hydrocracking of vacuum residue (VR) in batch system. Without RM, thermal cracking occurred and a lighter fraction and higher conversion was achieved than in the presence of catalyst. However, the catalytic cracking obviously inhibited both the coke formation and residue cracking reaction. We investigated the influence of reaction temperature, reaction time and RM concentration on VR conversion. Reaction temperature and time significantly improved the yield of naphtha, diesel and vacuum gas oil; unfortunately, they also increased the gas fraction, which is an undesirable product. Catalyst concentration negligibly affected the VR conversion while vacuum gas oil fraction in product distribution increased with catalyst concentration, indicating that the cracking reaction was suppressed in the presence of catalyst. Through the characterization of fresh and spent catalysts by diverse techniques, it has been determined that the crystalline iron oxide of RM transforms into pyrrhotite (Fe(x−1)Sx), an active phase for the hydrocracking reaction, due to presence of sulfur in VR. Our results show that RM is possibly self-activated during the reaction and the pretreatment step can be eliminated.

Valorisation of Waste Tires by Pyrolysis over a Fcc Catalyst in a Conical Spouted Bed Reactor

A commercial FCC catalyst based on a zeolite active phase has been used to perform the valorisation of waste tires by in situ catalytic pyrolysis. The process has been carried out in a conical spouted bed reactor provided by a continuous feeding system. The catalyst has been subjected to a steaming treatment in order to maximize diesel fraction. High diesel (50.5 wt %) and char (35 wt %) yields are obtained, together with low gas (0.6 wt %) and gasoline (13.9 wt %) fractions. The obtained liquid is highly aromatic, which is formed at the expense of the non-aromatic gasoline fraction.

Synthesis of High‐Quality Diesel with Furfural and 2‐Methylfuran from Hemicellulose

Hydroxyalkylation-alkylation (HAA) coupled with hydrodeoxygenation is a promising route for the synthesis of renewable high-quality diesel or jet fuel. In this work, a series of solid-acid catalysts were firstly used for HAA between lignocellulose-derived furan and carbonyl compounds. Among the investigated catalysts, Nafion-212 resin demonstrated the highest activity and stability. Owing to the high activity of the reactants and the advantage in industrial integration, the HAA of 2-methylfuran (2-MF) and furfural can be considered as a prospective route in future applications. Catalyst loading, reaction temperature, and time had evident effects on the HAA of 2-MF and furfural over Nafion-212 resin. Finally, the HAA product of 2-MF and furfural was hydrogenated over a Pd/C catalyst and hydrodeoxygenated over Pt-loaded solid-acid catalysts. Pt/zirconium phosphate (Pt/ZrP) was found to be the best catalyst for hydrodeoxygenation. Over the 4 % Pt/ZrP catalyst, a 94 % carbon yield of diesel and 75 % carbon yield of C15 hydrocarbons (with 6-butylundecane as the major component) was achieved.

Investigations on Hydrotreating of Fischer Tropsch-Biowaxes for Generation of Bio-Products from Lignocellulosic Biomass

The present study describes the application of Fischer Tropsch biowaxes as a feedstock in a pilot-scale hydroprocessing unit at operating conditions very similar to industrial size hydrotreating plants of traditional refineries. The project focus on a future coprocessing of biowax/gasoil blends due to produce bio-products derived from lignocellulosic biomass: crack gases, naphtha, kerosene, diesel and a residual product. Hydro-processing plants operating at mild cracking conditions support the production of high amounts in middle distillates at reduced coke formation. Premium bio-diesel and bio-kerosene with excellent cold flow properties are the main objective of the investigations. Various test runs with different hydrotreating catalysts have been conducted due to determine the influence of waxy feedstock on catalyst behavior and product distribution. Depending on the catalyst selected, the fixed bed reactor streamed by hydrogen operates under specified cracking condition defined by the following parameters: reactor temperature, hydrogen pressure and weight hourly space velocity (WHSV). Test runs with selected catalysts - isodewaxing (IDW), hydro-desulphurization (HDS) and the catalytic deparaffination (CDP) catalyst - have been executed at constant process conditions in order to compare the product spectrum and properties of product groups. Highest amounts of bio-diesel and bio-kerosene with excellent cold flow properties can be obtained with the IDW catalyst. This NiW- based catalyst with special additives generates cleaved and reshaped molecular fragments via skeletal isomerisation increasing the isoparaffin content of naphtha and middle distillates. Further investigations with this catalyst type have been executed due to determine the catalyst aging effect in a separate long term test run. The loss of cracking severity during operation of the catalyst can be observed by a steady decline in conversion. Unsaturated hydrocarbons such as olefins and diolefines in the bio-feedstock support the formation of a coke layer on the catalyst surface resulting in reinforced deactivation. As the consequence naphtha and finally the crack gases and the kerosene fraction are shifted to higher molecular fragments increasing the diesel and residue yield. Physicochemical properties of the product groups obtained during the test run vary and especially the cold flow properties from the diesel and kerosene fraction degrade significant. Balancing the conversion decline of the catalyst in operation can be realized by increasing the reactor temperature and the hydrogen pressure, but the effect is time limited.

Synthesis, characterization, and catalytic performance of high-silica Y zeolites with different crystallite size

High-silica NaY (SiO2/Al2O3>6.0) was synthesized without organic template in a novel, cheap, and relatively fast way by using as structure directing agent (SDA) a mixture of water glass, sodium aluminate, and sodium hydrate, which had been aged at low temperature. Liquid 27Al NMR characterization showed that the SDA nuclei aged at low temperature contained more silicon and were more stable than SDA prepared with the conventional method, thus inducing the formation of high-silica NaY during crystallization, as determined by XRD, XRF, and 29Si NMR. Particle size had a great effect on the structural stability of zeolite Y and catalytic cracking ability even at a high SiO2/Al2O3 ratio. In the cracking of vacuum gas oil, REY catalysts, made from high-silica NaY with crystallite size 300–500nm, not only had higher cracking activity, but also higher gasoline and diesel yield and lower coke yield than a conventionally prepared sample. On the other hand, REY catalysts with crystallite size between 100 and 300nm had a lower activity.

Production of high quality diesel from cellulose and hemicellulose by the Sylvan process: catalysts and process variables

The Sylvan (2-methylfuran) diesel process involves the conversion of pentose biopolymers into premium diesel via furfural, by means of hydroxyalkylation/alkylation and hydrodeoxygenation reactions. In the hydroxyalkylation/alkylation step two Sylvan molecules are reacted with an aldehyde or a ketone to yield C12+ oxygenated intermediate molecules. Thus, the manuscript describes first the performance of the hydroxyalkylation/alkylation step with different soluble and solid catalysts, and among solids delaminated zeolites were identified as promising catalysts. The scope of the process has also been studied by reacting Sylvan with different aldehyde and ketone molecules. It has been found that for the one-step trimerization of Sylvan, sulfuric acid appears the most adequate catalyst and can be reused. The final hydrodeoxygenation step is studied in detail starting with C14 intermediates generated from two Sylvan and one butanal molecules as well as with the product generated by direct trimerization of Sylvan to yield the final corresponding mono-branched paraffinic diesel product. The Sylvan diesel process is an environmentally friendly process able to produce a high yield (87%) of a premium diesel with a cetane number of >70 and upper pour point of −75 °C from non-food biomass.

Predictive Modeling of Large-Scale Integrated Refinery Reaction and Fractionation Systems from Plant Data. Part 1: Hydrocracking Processes

This paper presents a workflow to develop, validate, and apply a predictive model for rating and optimization of large-scale integrated refinery reaction and fractionation systems from plant data. We demonstrate the workflow with two commercial processes, a medium-pressure hydrocracking (MP HCR) unit with a feed capacity of 1 million tons per year and a high-pressure hydrocracking (HP HCR) unit with a feed capacity of 2 million tons per year in the Asia Pacific. The units include reactors, fractionators, and hydrogen recycle systems. With catalyst and hydrogen, the process converts heavy feedstocks, such as vacuum gas oil, into valuable low-boiling products, such as gasoline and diesel. We present the detailed procedure for data acquisition to ensure accurate mass balances and for implementing the workflow using Excel spreadsheets and a commercial software tool, Aspen HYSYS/Refining. Our procedure is equally applicable to other commercial software tools. The workflow includes special tools to facilitate an accurate transition from lumped kinetic components used in reactor modeling to the pseudo-components based on boiling point ranges required in the rigorous stage-by-stage simulation of fractionators. We validate the two models with 4 months of plant data, and the resulting models accurately predict unit performance, product yields, and fuel properties from the corresponding operating conditions. The MP HCR model predicts the yields of heavy naphtha, diesel fuel, and bottom products with average absolute deviations (AADs) of at most 3.4 wt %, predicts the specific gravities of heavy naphtha, diesel fuel, and bottom oil with AADs below 0.0184, predicts the flash point and freezing point of diesel fuel with AADs of 3.6 and 4.1 °C, respectively, and predicts the outlet temperatures of catalyst beds with AADs of 1.9 °C. The HP HCR model predicts the yields of liquefied petroleum gas (LPG), light naphtha, heavy naphtha, jet fuel, and residue oil with AADs below 1.7 wt %, predicts the specific gravities of light naphtha, heavy naphtha, jet fuel, and residue oil with AADs less than 0.134, predicts the flash point and freezing point of jet fuel with AADs of 1.6 and 2.3 °C, respectively, and predicts the outlet temperatures of catalyst beds of the two HCR reactors with AADs of 1.8 and 3.2 °C. We apply the validated plantwide model to quantify the effect of the H2/oil ratio on product distribution and catalyst life and the effect of HCR reactor temperature and feed flow rate on product distribution. The results agree well with experimental observations reported in the literature. Our resulting models only require typical operating conditions and routine analysis of feedstock and products and appear to be the only reported integrated HCR models that can quantitatively simulate all key aspects of reactor operation, fractionator performance, hydrogen consumption, product yield, and fuel properties.