Preparation of bio-fuels by catalytic cracking reaction of vegetable oil sludge

Biofuel production from vegetable oil is potentially a good alternative to conventional fossil derived fuels. Moreover, liquid biofuel offers many environmental benefits since it is free from nitrogen and sulfur compounds. Biofuel can be obtained from biomass (e.g. pyrolysis, gasification) and agricultural sources such as vegetable oil, vegetable oil sludge, rubber seed oil, and soybean oil. One of the most promising sources of biofuel is vegetable oil sludge. This waste is a major byproduct of vegetable oil factories. It consists of triglycerides (61%), free fatty acid (37%) and impurities (2%). The hydrocarbon chains of triglycerides and free fatty acid are mainly made up of C₁₆ (30%) and C₁₈ (36%) hydrocarbons. The others consist of C₁₂-C₁₇ hydrocarbon chains. Transesterification can help in converting vegetable oil sludge into biofuel. The disadvantage of this method is that a large amount of methanol is required. The alternative method for this conversion is catalytic cracking. The objective of this research is to evaluate and compare the pyrolysis process with cracking catalytic reaction of vegetable oil sludge by Micro-activity test MAT 5000 of Zeton-Canada.A ZSM-5/MCM-41 multiporous composite (MC-ZSM-5/MCM-41), was successfully synthesized using silica source extracted from rice husk. The material has the MCM-41 mesoporous structure, and its wall is constructed by ZSM-5 nanozeolite crystals. The porous system of the material includes pores of the following sizes: 5 Å (ZSM-5 zeolite), 40 Å (MCM-41 mesoporous material), and another porous system whose diameter is in the range of 100-500 Å (mesoporous system) formed by the burning of organic compounds that remain in the material during the calcination process. This pore system contributes to an increase in the catalytic performance of synthesized material.The results of vegetable oil sludge cracking reaction show that the product consists of fractions such as dry gas, liquefied petroleum gas (LPG), gasoline, light cycle oil (LCO), and (heavy cycle oil) HCO, which are similar to those of petroleum cracking process.MC-ZSM-5/MCM-41 catalyst is efficient in the catalytic cracking reaction of vegetable oil sludge as it has higher conversion and selectivity for LPG and gasoline products in comparison to the pyrolysis process. Product distribution (% of oil feed) of cracking reaction over MC-ZSM-5/MCM-41 is coke (3.4), total dry gas (7.0), LPG (31.1), gasoline (42.4), LCO (8.9), HCO (7.2); and that of pyrolysis are coke (19.0), total dry gas (9.3), LPG (16.9), gasoline (28.8), LCO (13.7), and HCO (12.3).These results have indicated a new way to use agricultural waste such as rice husk for the production of promising catalysts and the processing of vegetable oil sludge to obtain biofuel.     

Investigation of the components in RFCC gasoline affecting the accuracy of potentiometric titration by GC-MS and GC-IR

This paper described that there were two or more endpoints in the curve when potentiometeric titration was used to determine the contents of mercaptan sulfur in residue fluidized catalytic cracking (RFCC) gasoline. Comparing with the one endpoint of a mixture solution of C₂–SH to C₁₀–SH determined under the same conditions, we found some components in RFCC gasoline affected the result of titration. A facile method washing the gasoline with 2 wt.% HCl solution was brought out to eliminate the interfering components from the RFCC gasoline. After being treated with this method, all RFCC gasoline that contained 14–27 μg/ml mercaptan sulfur (S_RSH) met the quality specification (S_RSH shall not exceed 10 μg/ml) [GB 17930-1999, Chinese national standard for unleaded petrol (gasoline) for motor vehicles]. The analysis of gas chromatography-mass spectrometry (GC-MS) and gas chromatography-infrared spectrometer (GC-IR) verified that the interfering components were aniline, phenol and their alkyl-substituted derivatives.     

Conversion of vegetable oils under conditions of catalytic cracking

The effect of the composition of zeolite containing catalyst, the conditions of conducting the process, and the nature of oils on the distribution of target products during conversion under conditions of catalytic cracking is studied. The study is performed on bizeolite catalysts containing zeolites (ultrastable Y and ZSM-5 at different ratios) and on catalyst LUX containing18 wt % of zeolite Y in the HREY form. It is shown that the presence of zeolite ZSM-5 in the catalyst composition promotes the formation of olefines C₂–C₄. An increase in the severity of cracking process (elevated temperatures and catalyst: raw material ratios) improves the yield of gaseous products and coke with a simultaneous reduction in the yield of the gasoline fraction. The effect the nature of vegetable oils has is studied using the examples of palm, rapeseed, mustard, and sunflower oils. It is demonstrated that for the maximum yield of olefines C₂–C₄ and gasoline, we must use oils with elevated contents of saturated fatty acids. The regularities of the simultaneous cracking of sunflower oil and vacuum gas oil are studied. It is been found that upon simultaneous cracking, the total conversion of the mixed feedstock and yield of gasoline fraction increase; the maximum effect is attained with the addition of 3–10 wt % of vegetable oil.     

Fuels by pyrolysis of waste plastics from agricultural and packaging sectors in a pilot scale reactor

The pyrolysis of waste plastics (so called chemical recycling) is one perspective way of their utilizations, but the end product properties are a key point of the industrial leading of processes. In this paper a pilot scale pyrolysis process has been investigated. Waste plastics were decomposed in a tube reactor at 520 °C, using hourly feed rate of 9.0 kg. Raw materials were selectively collected wastes from agricultural and packaging industry. For supporting the more intensive cracking of CC bonds of main polymer structure a commercial ZSM-5 catalyst was tested in concentration of 5.0%. Products were separated into gases, gasoline, light and heavy oil by distillation. Plastic wastes could be converted into gasoline and light oil with yields of 20–48% and 17–36% depending on the used parameters. The gas and liquid products had significant content of unsaturated hydrocarbons, principally olefins. In the presence of ZSM-5 catalyst the yields of lighter fractions (especially gasoline) could be considerably increased and the average molecular weight of each fraction has decreased. Gasoline had C₅–C₁₅ hydrocarbons, while light oil had C₁₂–C₂₈. The used catalyst has promoted the formation of i-butane in gases and affected the composition of both gasoline and light oil. Properties of products are advantageous for fuel-like applications, and they are able to increase the productivity of refinery. On the other hand the possibility for further utilization of products from pyrolysis basically was affected by the source and the properties of raw materials. Waste polyethylene from agricultural consisted of some elements from fertilizers (N, S, P and Ca), which could not be removed from the surfaces of raw materials by pre-treatment (e.g. washing). In that case significant concentration of N, S, P and Ca can be measured in all products, but the catalyst has decreased the concentration of impurities. Gasoline, light oil and heavy oil were nitrogen free and sulphur content was below 12 mg/kg in hydrocarbons obtained by the pyrolysis of polypropylene waste from packaging.     

The role of paraffin wax in the formation of minor products in the catalytic cracking of petroleum distillates over La-Y

An investigation of the role of paraffin wax in the catalytic cracking of wax-bearing petroleum distillates has been carried out in a fixed-bed reactor containing La-Y catalyst over a temperature range from 482° to 524°C. By using the concept of initial product selectivity derived from the time-on-stream theory of catalyst decay, it was found that increasing the wax content of the feedstocks resulted in an increase in the yield of C₅⁺ gasoline and a decrease in the yields of most of the gaseous products and of coke. Ethane and propylene and the olefin content of the gasoline increased in yield with the addition of wax. The mixing of cracking feedstocks has only a linear effect on the reactivity and no synergistic effects in any of the observed properties of the reaction are in fact observed.     

The role of paraffin wax in the formation of minor products in the catalytic cracking of petroleum distillates over la-y

An investigation of the role of paraffin wax in the catalytic cracking of wax-bearing petroleum distillates has been carried out in a fixed-bed reactor containing La-Y catalyst over a temperature range from 482° to 524°C. By using the concept of initial product selectivity derived from the time-on-stream theory of catalyst decay, it was found that increasing the wax content of the feedstocks resulted in an increase in the yield of C₅⁺ gasoline and a decrease in the yields of most of the gaseous products and of coke. Ethane and propylene and the olefin content of the gasoline increased in yield with the addition of wax. The mixing of cracking feedstocks has only a linear effect on the reactivity and no synergistic effects in any of the observed properties of the reaction are in fact observed.     

Characterization of Modified Nanoscale ZSM-5 Zeolite and Its Application in the Olefins Reduction in FCC Gasoline

Nanoscale HZSM-5 zeolite was hydrothermally treated with steam containing 0.8 wt% NH₃ at 773 K and then loaded with La₂O₃ and NiO. Both the parent nanoscale HZSM-5 and the modified nanoscale HZSM-5 zeolites catalysts were characterized by TEM, XRD, IR, NH₃-TPD and XRF, and then the performance of olefins reduction in fluidized catalytic cracking (FCC) gasoline over the modified nanoscale HZSM-5 zeolite catalyst was investigated. The IR and NH₃-TPD results showed that the amount of acids of the parent nanoscale HZSM-5 zeolite decreased after the combined modification, so did the strong acid sites deactivating catalysts. The stability of the catalyst was still satisfactory, though the initial activity decreased a little after the combined modification. The modification reduced the ability of aromatization of nanoscale HZSM-5 zeolite catalyst and increased its isomerization ability. After 300 h onstream, the average olefins content in the gasoline was reduced from 56.3 vol% to about 20 vol%, the aromatics (C₇–C₉ aromatics mainly) and paraffins contents in the product were increased from 11.6 vol% and 32.1 vol% to about 20 vol% and 60 vol% respectively. The ratio of i-paraffins/n-paraffins also increased from 3.2 to 6.6. The yield of gasoline was obtained at 97 wt%, while the Research Octane Number (RON) remained about 90.     

Effect of process conditions on the composition of products in the conventional and deep catalytic cracking of oil fractions

With the purpose of increasing the yield of light C₂-C₄ olefins in comparison with that in conventional catalytic cracking, we experimentally study the effect of temperature and catalyst-to-oil ratio on the distribution of the basic products of oil catalytic cracking on the bizeolite and industrial LUX catalysts. The bizeolite catalyst contains ZSM-5 and ultrastable Y zeolites in equivalent amounts, while the LUX catalyst contains 18 wt % of Y zeolite in the HRE form. As shown by the results of our tests, the yield of C₂-C₄ olefins and gasoline in the deep catalytic cracking of hydrotreated vacuum gasoil on the bizeolite catalyst within a range of catalyst-to-oil ratios of 5–7 and temperatures of 540–560°C reaches 32–36 and nearly 30 wt %, respectively. In cracking on the LUX catalyst under similar conditions, the yield of light olefins and gasoline is 12–16 and 37–45 wt %, respectively. The distribution of target products in the deep catalytic cracking of different hydrocarbon fractions (vacuum gasoil, gas condensate, its fraction distilled from the cut boiling below 216°C, and the hydrocracking heavy residue) on the bizeolite catalyst is studied. It is shown that the fractions of gas condensate and hydroc-racking residue can serve as an additional source of hydrocarbon raw materials in the production of olefins.     

Modeling and optimization of Fischer–Tropsch products hydrocracking

The hydrocracking behavior the product of a Fischer–Tropsch synthesis consisting of a C₄–C₃₀ mixture of paraffins and olefins on a platinum/amorphous silica–alumina catalyst has been analyzed and optimized. The influence of temperature on the selectiveness of the hydrocracking has been investigated. Time and temperature optimization was performed in order to obtain the best operating conditions for the enhancement of gasoline and diesel cuts. This work presents a mathematical model of the tubular reactor used in hydrocracking the heavy hydrocarbon fraction produced by the Fischer–Tropsch synthesis. The system was studied to optimize the operating conditions as to produce the highest amounts of diesel and/or gasoline. The hydrocarbon product distribution changes during hydrocracking were modeled considering a commercial bifunctional catalyst. The model was validated with data reported in the literature and has presented a satisfactory fitting to the experimental data with a confidence level of 95%. The production of specific cuts such as diesel and gasoline was optimized after the model has been validated. The results showed that lower temperatures (550 K) favor the cracking of heavy hydrocarbons chains into diesel and higher temperatures (650 K) favor a more effective cracking generating higher amounts of gasoline.     

Structural characterization of Bombay High crude oil fractions by nuclear magnetic resonance spectroscopy

Different fractions of Bombay High crude oil have been characterized using ¹³C and ¹H n.m.r. spectrometry. The distribution of various types of hydrogens and carbons has been reported and several average structural parameters of the fractions have been compiled. Relative variation of structural parameters has been discussed. The data on light cycle oil (LCO) has also been presented and compared with the feed (vacuum gas oil, VGO) data. The study reveals that all the four samples/fractions are predominantly paraffinic, VGO being richest in n-paraffins. The comparison of LCO and VGO data indicates a slight reduction in the n-paraffinic chain during catalytic cracking.     

Enhanced Production of C2–C4 Olefins Directly from Synthesis Gas

An attempt made for the selective production of C₂–C₄ olefins directly from the synthesis gas (CO + H₂) has led to the development of a dual catalyst system having a Fischer–Tropsch (K/Fe–Cu/AlOx) catalyst and cracking (H-ZSM-5) catalyst operate in consecutive dual reactors. The flow rate (space velocity) and H₂/CO molar ratio of the feed have been optimized for achieving higher CO conversions and olefin selectivities. The selectivity to C₂–C₄ olefins is further enhanced by optimizing the reaction temperature in the second reactor (cracking), where the product exhibited 51% selectivity to C₂–C₄ hydrocarbons rich in olefins (77%) with a stable time-on-stream performance in a studied period of 100 h.     

An experimental and modeling study of vacuum residue upgrading in supercritical water

Arabian Heavy crude oil was fractionated into distillate and vacuum residue fractions. The vacuum residue fraction was treated with supercritical water (SCW) at 450°C in a batch reactor for 15–90 min. The main products were gas, coke, and upgraded vacuum residue; the upgraded residue consisted of gasoline, diesel, and vacuum gas oil range components. The molecular composition of gas and upgraded vacuum residue was analyzed using gas chromatography (GC, GC × GC). SCW treatment converted higher carbon number aliphatics (≥C₂₁) and long‐chain (≥C₅) alkyl aromatic compounds into C₁?C₂₀ aliphatics, C₁?C₁₀ alkylaromatics, and multiringed species. The concentrations of gasoline and diesel range compounds were greater in the upgraded product, compared to the feed. A first‐order, five lump reaction network was developed to fit the yields of gas, coke, diesel, and gasoline range components obtained from SCW upgrading of vacuum residue. Distillation of crude oil followed by SCW treatment of the heavy fraction approximately doubled the yield of chemicals, gasoline, and diesel, while forming significantly less coke than conventional upgrading methods. © 2018 American Institute of Chemical Engineers AIChE J, 64: 1732–1743, 2018     

Semicoking of Kansko-Achinsk lignite and applications of tar fractions

The semicoking of regular lignite from the Berezovsk field in Kansko-Achinsk Basin (moisture content 1.6–19.6 wt %) at 450–550°C in a reactor with solid heat carrier is studied. The products are semicoke (up to 68.1%), tar (up to 9.5%), gas (up to 31.9%), and pyrogenetic water. The composition of the semicoking gas is quantitatively determined. Its main components are hydrogen (up to 71.7%) and methane (up to 17.2%). The heat of combustion of the semicoking gas is 12.39–16.25 MJ/m³. The yield of phenolic fractions in the semicoking tar, consisting of phenol and its alkyl derivatives with one or two short substituents (C₁–C₃), is 10.5–14.6%. After hydraulic purification of the gasoline fraction in the semicoking tar (below 180°C), gasoline with octane rating 75.8 (by the motor method) is obtained. It consists of aromatic, saturated, and unsaturated hydrocarbons (C₅–C₈). The diesel fuel derived from tar fractions distilled off at temperatures up to 350°C are of good quality, except for their low cetane rating. The high-boiling tar fractions may be used to produce lignite pitch and pitch coke. The semicoke obtained is a very effective reducing agent in the production of phosphorus. It may also be used as a lean additive in coking batch and as a component in enriched domestic coal briquets.     

FD2G加氢转化技术研发及应用

目前我国炼油市场柴汽比下降、环保法规日趋严格,催化柴油(LCO)油品价值降低,炼油企业急需调整产品结构,为其寻找新的出路。而国内面临着高辛烷值汽油短缺的情况,因此将催化柴油转化为高辛烷值汽油是一条降低柴汽比、增产汽油的有效途径。结合催化柴油的性质从反应机理、试验数据及工业应用等方面介绍了FD2G加氢转化技术。结果表明:FD2G加氢转化技术可将催化柴油加氢转化为高辛烷值汽油和清洁柴油调和组分,同时可生产轻质芳烃原料等高附加值产品。     

Synthesis of isoalkanes over Fe–Zn–Zr/HY composite catalyst through carbon dioxide hydrogenation

The reaction path of isoalkanes formation via CO₂ hydrogenation was studied over the Fe–Zn–Zr/HY composite catalyst, which gives high selectivity to isoalkanes. The results indicate that the reverse water–gas shift reaction is not the indispensable step for the synthesis of hydrocarbons. And i-C₄ (iso-butane) is formed from propylene and methanol through MTG (methanol to gasoline) reaction and i-C₅ (iso-pentane) obtained from the reaction of C₂ and C₃ through the additive dimerization. A part of C₁, C₄ is formed on the sole Fe–Zn–Zr catalyst from methanol for the CO₂ hydrogenation over Fe–Zn–Zr/HY composite catalyst.     

On the Applicability of the Regular Solution Theory to Multicomponent Systems

The critical micelle concentration (CMC) of aqueous mixtures of decyl- (C₁₀TAB), dodecyl- (C₁₂TAB), and tetradecyl trimethyl ammonium (C₁₄TAB) bromides has been studied in the complete triangular diagram. The results have been analyzed on the basis of the multicomponent regular solution theory for mixed micelles (MRST). It has been found that the mixtures of both, two or three components, contrary to the MRST theory assumptions, have a nonideal behavior. Both the experimental CMC, (CMC _ijk )_exp, and that computed with the MRST, (CMC _ijk )_calc), were lower than the ideal one, (CMC _ijk )_id, indicating an attractive interaction. Moreover, in the majority of the triangular diagram (CMC _ijk )_exp differs significantly from (CMC _ijk )_calc. This suggests that the assumption in the MRST that the interaction among the three different homologue molecules in the mixed micelle computed using the binary regular solution theory interaction parameters obtained from binary mixtures may be an oversimplification. This has been reinforced by analysis of the intramicellar activity coefficients of components, indicating differences in the surrounding of the component molecules when they are in bi- or tricomponent micelles. The excess free energy of micellization in three-component systems indicates that the more stable mixed micelles are those having an excess of the shorter components (C₁₀TAB–C₁₂TAB) and <50 % of the longer one (C₁₄TAB). Furthermore, the common statement that mixtures of homologue surfactants are ideal is not supported by this work.     

Determination of benzene and total aromatics in commercial gasolines using packed column GC and NMR techniques

A simple, accurate and rapid method has been developed for the estimation of benzene and total aromatics (0.5-50% w/w) including heavier aromatics (C₈, C₉, and C₁₀) in commercial gasoline using packed column GC and NMR techniques. The benzene content can be estimated as low as 0.1% w/w. The response of a flame ionisation detector (FID) to each major aromatic group in gasoline was calculated using internal standard. The results have been compared with the NMR and standard ASTM D5580 methods. The limitations of NMR and GC techniques for the estimation of total aromatics particularly in reformulated gasoline containing oxygenates have been discussed and attempts have been made to overcome problems associated with the analysis. The results obtained by both the techniques for a number of commercial gasoline samples containing olefins or free of olefins received from different refineries processing variety of crudes using different refining technologies have shown excellent correlation. The ¹H NMR method has a wider scope, convenient and fast, and also applicable to heavier naphtha. The method can routinely be adopted for the quality control of commercial gasoline at refinery as well as marketing terminals for monitoring benzene and total aromatic content. The time consumption for single run using gas chromatographic technique is approximately 35 min.     

A study on the dimerization of 1-butene over Beta zeolite

New restrictions on gasoline in some part of the world implies that oxygenates such as MTBE and aromatics should be replaced by other high-octane components. The dimerization of 1-butene, which is a step in the production of “Green” gasoline, is evaluated under liquid phase reaction conditions over acidic Beta zeolites synthesized with different synthesis time. There are substantial differences between Beta zeolites obtained at synthesis times 96 and 240 h leading to different physico-chemical properties and, furthermore, catalytic performances. More acidic Beta zeolites lead to higher yields to light olefins while less acidic samples produce more oligomers, i.e. C₁₂–C₁₄ fraction. Interestingly, it was also observed that strong acid sites catalyze cracking reactions, while the weak ones, oligomerization.     

Catalytic dehydromethylation of methylcyclohexane and the simultaneous transformation of fractions of straight-run gasoline and methanol with modified forms of mordenite and pentasil

Results are presented from studies of the dehydromethylation (DHM) of methylcyclohexane (MCH) and the simultaneous transformation of straight-run gasoline fractions and methanol on modified forms of mordenite and pentasil in the presence of various hydrogen acceptors (O₂, CO₂). High selectivity on xylene isomers is observed for polycationic modifications of HNa-TsVM. On such catalytic systems, the degrees of DHM and dehydrodisproportionation (DHD) of MCH grow with an increase in O₂-to-CO₂ ratio in the range of 0.05 : (1–1.5), while the degree of its dehydrogenation to toluene is virtually constant. High yields of di- and trimethylbenzenes are achieved in the reactions between methanol and gasoline fractions composed mainly of C₇–C₈ hydrocarbons at 100–140 °C. The results from this study can be used for straight-run gasoline reforming with the aim of increasing the yield of C₈-C₉ aromatic hydrocarbons.     

Phase composition,microstructure, and properties of Al4O4C–(Al2OC)1-x(AlN)x –Zr2Al3C4–Al2O3 refractories prepared at high temperatures in nitrogen

The novel Al₄O₄C–(Al₂OC)_1-x(AlN)_x–Zr₂Al₃C₄–Al₂O₃ refractories with ultra-low carbon content have been successfully prepared by constructing the core-shell structure of aluminum at 1300–1700°C in nitrogen. The phase composition, microstructure, and properties of the novel refractories are deeply investigated. The cracking temperature on the core-shell structure of aluminum is further explored and the reaction mechanism of Zr₂Al₃C₄ has also added explanation. The results show that the novel refractories have excellent physical properties and cannot be corroded by molten iron. There exist two different Al₂OC solid solutions in the novel refractories, Al₂OC-rich (Al₂OC)_1-x(AlN)_x and AlN-rich (Al₂OC)_1-x(AlN)_x. The temperatures affect their relative content. When temperatures are less than 1600°C, the relative content of Al₂OC-rich (Al₂OC)_1-x(AlN)_x is more than that of AlN-rich (Al₂OC)_1-x(AlN)_x. When temperatures are above 1700°C, the relative content of AlN-rich (Al₂OC)_1-x(AlN)_x is more than that of Al₂OC-rich (Al₂OC)_1-x(AlN)_x. The core-shell structure of aluminum fully ruptures at about 1200°C. Zr₂Al₃C₄ begins to form at about 1000°C and generates in large at 1200°C.