Oil & Gas Research
Open Access

Alkanes; Processes; Octane number; Catalyst; Chemical composition

Introduction

Large hydrocarbon deposits are located on the home of the Caspian Sea, which are characterized by specific geostrategic, geographical, military and political features. In addition to oil painting and gas coffers, the position between the main deals requests in the West and East is of great strategic significance. In the Aktobe region of the Republic of Kazakhstan, ferocious hydrocarbon product is carried out at the Zhanazhol, Kenkiyak, Kokzhide and Bashenkol fields [1]. The ways of dealing Kazakh oil painting moment depend on the complex processing of diligence, where oil painting is the feedstock for carrying the final product. This happens due to the fact that the capacity and technological outfit of the applicable oil painting refineries isn’t concentrated on rooting the entire range of products contained in raw accoutrements. oil painting is a complex raw material, from which a wide range of petroleum products can be attained. Processing into energy, oil painting and mixed directions prevails in terms of the technological schemes of product. In real conditions, oil painting refining is carried out according to the principle of maximum profitable benefit [2]. Processing comprises the ensuing stages disquisition, product, transportation, processing, taking into account the use of all free capacities. The preface of the process of hydrocatalytic isomerization of straight- run gasoline fragments of Zhanazhol oil painting into the operation of oil painting refineries determines the applicability of studying this process, as well as the need for scientific exploration in the development of technology for isomerization processes and the selection of catalysts that will insure optimal conditions for isomerization responses. Catalysts used in colorful isomerization technologies have a common kinetic pattern at high temperatures, the yield of isoalkanes is limited by thermodynamic equilibrium, while at low temperatures, the response rate diminishments. Upon reaching the maximum yield of isomerizate with a given octane number( 80 – 90), it’s necessary to probe the concession between the reactivity of the catalyst and the conditions for creating the thermodynamic equilibrium of the process [3]. Also, it’s important to elect a catalyst to insure the minimal yield of sweet composites and olefins. In the petrochemical assiduity, hydrocatalytic isomerization depends on colorful normal chain paraffins. Hydrocatalytic isomerization of C4- C7 hydrocarbons is used in the product of gasoline with a high octane number. Hydrocatalytic isomerization of C7- C15 hydrocarbons is used to produce diesel energy with bettered low- temperature characteristics while maintaining high cetane figures of the original diesel fragments. Isomerization of hydrocarbons with a chain length lesser than C15 is used to gain slicking canvases with a high density indicator and bettered low temperature parcels. As the hydrocarbon chain attached to sweet or naphthenic rings branches and the number of side chains increases, the melting point of hydrocarbons decreases. Paraffin hydrocarbons starting with C12H26 have advanced melting points than fanned bones [4]. Also, the low- temperature parcels of isoparaffinic hydrocarbons of the same molecular weight are different and depend on the length and number of alkyl revolutionaries. The end of the exploration is to develop individual approaches to the use of the gasoline bit of the Zhanazhol oil painting and gas condensate field as a raw material for the process of hydrocatalytic isomerization. These styles will help to effectively break the issue of the need for high- quality energy, lubricants, petroleum coke and petrochemical feedstock. The main task of the exploration is to gain information on the chemical composition of oil painting from the Zhanazhol field grounded on gas chromatography and to determine the relationship between the molecular characteristics of gasoline fragments of oil painting and the effectiveness of hydrocatalytic isomerization [5].

Materials and Method

The exploration object is light gasoline fragments of oil painting from the Zhanazhol field of the Mugalzhar District of the Aktobe Region. The process of hydrocatalytic isomerization to ameliorate energy quality has been studied in detail. Also, the paper gives a chemical assessment of the gasoline fragments of oil painting from the Zhanazhol field, according to the state standard styles for the study of oil painting and gas feedstock GOST 33364 – 2015 “ oil painting and petroleum products, liquid [6]. system for determining viscosity, relative viscosity, and API graveness determination with a hydrometer ”, GOST 31391 – 2009 “ Petroleum products. Transparent and opaque liquids. Determination of kinematic density and computation of dynamic density ”( 22), GOST 2177 – 99 “ Petroleum products. system for determining the fractional composition of petroleum products ”( 23), GOST 20287 – 91 “ Petroleum products styles for determining the temperatures of fluidity and solidification ”( 24), GOST 32139 – 2019 “ Petroleum and petroleum products. Determination of sulfur content by energy dispersiveX-ray luminescence spectrometry system ”, GOST R 51941 – 2002. “ Gasolines [7]. Determination of aromatics in finished gasoline by gas chromatography system ”. Fractional composition according to ASTM D86 “ Standard Test Method for Distillation of Petroleum Products at Atmospheric Pressure ”. The distillation of the petroleum feedstock was carried out in a batch laboratory unit at ambient pressure under conditions that are designed to give separation with roughly- one theoretical plate. At the same time, the boiling point and the volume of the condensate were recorded. A analogous fractional system for the determination of C2- C5 hydrocarbons in gasolines was carried out by gas chromatography ASTM D2427- 06 “ Standard Test system for Determination of C 2 through C 5 Hydrocarbons in Gasolines by Gas Chromatography ”, also applicable for the determination of the content of monoolefins, cyclic olefins, diolefins or acetylenes. The anatomized samples shouldn’t contain a significant quantum of factors, the boiling point of which is lower than the boiling point of ethylene. According to this ASTM D4420- 94 “ Standard Test system for Determination of Aromatics in Finished Gasoline by Gas Chromatography ” system, sweet hydrocarbons in the composition of gasolines were determined by the system of a chromatographic system of two columns connected to a thermal conductivity sensor and two cathodes( or two sensors with one cathode). A reproducible volume of samples entered the column containing the polar liquid phase [8]. The range of attention of sweet factors determined in gasoline benzene from0.1 to5.0; toluene from1.0 to20.0; sweet C8 from3.0 to25.0; sweet C9 and heavier from5.0 to30.0; total volume bit of sweet hydrocarbons ranges from10.0 to80.0. ASTM D4052 “ Standard Test Method for Density, Relative viscosity, and API graveness of Liquids by Digital Density Meter ” gasoline viscosity was measured according to the standard system for determining the viscosity and relative viscosity of liquids using a digital viscosity cadence. The system comported in changing the oscillation frequence of a liquid sample in an oscillating tube and determining the viscosity of the sample from the change in the mass of the tube. The isomerization of n- alkanes of the gasoline bit was studied in a high- pressure inflow unit with a stationary catalyst bed, at a certain temperature, pressure and space haste. The main element of the n- alkane isomerization device is a pristine- sword reactor with a catalyst volume of 50 – 100 cm3 under high pressure. The reactor is equipped with a line of heaters. The temperature in the reactor and the catalyst bed is controlled by a system of calibrated thermocouples connected to a potentiometer. Hydrogen is supplied from a cylinder for hydroprocessing response and catalyst recovery [9].

Results and Discussion

Catalyst characterization

As forenamed in Section2.2, the catalysts, as well as the support, have been characterized by several ways in order to relate their features with their physicochemical parcels. The effect of essence deposit can be seen by comparing these results with those of the support, whose top parcels can be set up. The pervious structure is slightly affected by the objectification of the essence. Pt deposit substantially affects the drop of the micropore volume, while Pd deposit affects the mesopore volume [10]. This isn’t only related to the lower quantum of platinum with respect to precaution, but also to its lower flyspeck size, suggesting the deposit of Pt inside or at the mouth of the micropores, while Pd is deposited on the mesopores. On the other hand, both total acidity and acid strength drop more oppressively for Pd, indicating that its deposit takes place on the stronger acid spots, blocking the availability to Brönsted and Lewis spots, as Pt is placed on weaker centers. The N2 adsorption/ desorption isotherms have been depicted. It can be seen that the donation of the micropores( measured at relative pressures<0.2) to the specific face is relatively poor, which is in concordance with the low content of zeolite of the equilibrium FCC catalyst(13.8 wt). On the negative, the presence of meso and macropores is openly egregious, exposing the effect of the matrix used in the expression of the support. Indeed, both isotherms display type H3 hysteresis circles, which are generally associated with mesoporous accoutrements that contain essay- bottle pores. The isotherms attained for both catalysts are relatively analogous, as it can be ratified attending to the values for the textural parcels collected. Therefore, the Pd/ FCC catalyst shows a slightly advanced specific face than Pt/ FCC catalyst( 115 and 106 m2 g −1, independently) grounded on a advanced donation of the micropores that give a advanced micropore volume(0.032 vs0.029 mL g −1, independently) [11].

Conversion, selectivity and products yields

A displays the elaboration of the conversion with TOS in the hydrocracking of HT- LCO with both Pd/ FCC and Pt/ FCC catalysts for the whole range of temperatures studied. It can be seen that in all cases that conversion decreases until it reaches a steady value, which is kept along the time. It should be noted that high temperatures held up the reaching of the steady values, as catalyst exertion is promoted at high temperatures, especially the cracking one. The drop may be caused by(i) the deposit of heteroatoms, i.e. S and N, preferentially on the metallic function of the catalysts,(ii) the deposit of essence on both the acidic and metallic functions of the catalysts; and(iii) the deposit of coke causing a partial collapse of the hydrocracking exertion. From the forenamed causes, the possible goods of the deposit of S, N and essence can be considered minor, since the LCO has been hydrotreated in a former stage to minimize their contents and alleviate the poisoning they may beget. Indeed, comparing the results depicted a with those preliminarily reported by Gutiérrez etal.in the hydrocracking of LCO on precious essence- grounded catalysts, the conversion decay attained by them is significantly more pronounced. Hence, it can be considered that the deposit of coke is the most influential factor in catalyst deactivation. This statement is supported not only by the fact that the quantum of N and S will be lower in the hydrotreated LCO but also by the effect of temperature on the mechanisms of coke conformation. In general, catalyst deactivation by coke conformation tends to increase with adding the response temperature by favoring the extent of the condensation responses of the coke precursors still, the degree of deactivation, in this case, dropped with adding the response temperature. This could be credited to the creation of the hydrogenation responses of coke precursors, modifying the coke quantum and its nature.

Conclusions

The hydrocracking of apre-hydrotreated light cycle oil painting( HT- LCO) has been delved with the end of carrying a high- quality gasoline bit. Both catalysts show a great performance since the gasoline bit has been easily maximized in the whole range of temperatures studied, but it has been easily promoted at 400 °C. The values attained for a TOS = 8 h at this temperature have been of 64 and 79 wt for Pd/ FCC and Pt/ FCC catalysts, independently. Likewise, this high yield of gasoline has come with a negligible conformation of feasts( below 1 wt with both catalysts). Concerning the composition of the gasoline bit, Pt/ FCC catalyst has allowed for carrying a gasoline bit with attention of aromatics below the limits established by the current legislation. It should be stressed that for a temperature of 400 °C the attention of aromatics has been only 16 wt. Pd/ FCC catalyst has reached the legal limits just at 360 and 400 °C, being the ultimate temperature the bone that offers the lowest attention of aromatics( 20 wt). The TPO biographies of the spent catalysts have exposed the presence of two fragments of coke deposited on the matrix and in the micropores of the HY zeolite of the catalyst. The low combustion temperature of this last type of coke( specific of a low advanced coke) indicates that the presence of the matrix and the exertion of the catalyst for the hydrocracking of the coke precursors avoid their condensation towards further advanced structures and the posterior blocking of the micropores of the zeolite. This restriction of the deactivation explains the pseudoestable state of exertion reached by the catalysts( advanced in the case of the Pt/ FCC catalyst) that ensures good results for the hydrocracking of the HTLCO.

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