Straight-run Naphtha Research Articles

Determination of mutual solubility in the straight-run naphtha—propylene oxide—water system

The melting (crystallization), separation, and boiling points of a mixture of propylene oxide and water were determined and used to plot the phase diagram of the mixture. The composition of propylene oxide crystal hydrate was investigated. The triangular diagram of separation of the system at 20°C was plotted with the results of studying the mutual solubility in the ternary straight-run naphtha – propylene oxide – water system.

Hydroprocessing of Fischer–Tropsch biowaxes to second-generation biofuels

Upgrading of Fischer–Tropsch (FT) biowaxes to second-generation biofuels via hydroprocessing is the final step for increasing the fuel amount of the overall biomass conversion route: gasification of lignocellulosic biomass, FT synthesis, and hydroprocessing. The typical FT product portfolio consists of high molecular weight paraffinic waxes as the main product and FT fuels in the diesel and naphtha boiling range. OMV's objective and contribution to the project focus on achieving coprocessing of FT biowaxes with fossil feedstock using existing hydrotreating plants of crude oil refineries. Various test runs have been examined with a conventional refining catalyst under mild conditions (380–390°C, 5.8 MPa; WHSV, 0.7–1.3 h−1) in a pilot plant. Pure FT biowax is converted to gases, fuels, and an oil/waxy residue in a fixed-bed reactor with a porous catalyst layer technology. The presence of hydrogen in the reaction chamber reduces the fast deactivation of the catalyst caused by the formation of a coke layer around the catalyst particle surface and saturates cracked hydrocarbon fragments. Another approach is the creation of synthetic biodiesel components with excellent fuel properties for premium fuel application. Basically, premium diesel fuel differs from standard diesel quality by cetane number and cold flow properties. Hydroprocessed synthetic biodiesel (HPFT diesel) has compared to conventional diesel advantages in many aspects. Depending on the catalyst selected, premium diesel quality can be obtained by shifting cold flow operability properties of HPFT fuels to a range capable even under extreme cold conditions. In addition, a high-quality kerosene fraction is obtained to create bio jet fuels with an extremely deep freezing point, as low as −80°C. The isomerization degree, as well as the carbon number distribution of high paraffinic profile, and the branching degree have a major impact on the cold flow properties and cetane number. FT diesel has, compared to HPFT diesel, a slightly higher derived cetane number (DCN > 83) and a cloud point of −9°C, whereas HPFT diesel reaches values as low as −60°C. Although the HPFT naphtha obtained consists of high amounts of isoparaffins, the RON/ MON values are comparable to fossil straight-run naphtha. The reason is that the branching degree of isoparaffins from the naphtha fraction is not sufficiently high enough to reach the typical octane number values of gasoline products delivered at filling stations. Assuming the goal of launching a premium biodiesel or biokerosene fuel to the market, these hydroprocessed synthetic biofuels from FT biowaxes are ideal blending components.

Catalytic cracking of n-heptane over HZSM-5 catalysts with the activation of lattice oxygen

Paraffin, one of the major components of straight-run naphtha, is relatively inert compared with olefin, which poses a difficulty for catalytic cracking of naphtha. The present study proposed introducing lattice oxygen into previous HZSM-5 catalyst system to improve conversion and light olefin selectivity. Vanadium oxide based catalyst was prepared separately as the lattice oxygen provider and then mixed with HZSM-5 catalyst for evaluation in a fixed-bed reactor using n-heptane as model compound. The results demonstrated that conversion of reactant increased from ∼51% to ∼59% by replacing 20% of HZSM-5 catalyst with V 2O 5/Al 2O 3; depending on different location of V 2O 5/Al 2O 3 relative to HZSM-5 catalyst in the reactor, conversion and product distribution varied significantly, while the addition of pure alumina did not have such an effect. Besides, water was formed in liquid products accompanied by reduction of V 5+ during the reaction, as revealed by FT-IR and XRD results, respectively; the oxidized V 5+ seemed to have greater capability in promoting conversion of n-heptane. Therefore, it was concluded that n-heptane could be activated by lattice oxygen provided by oxidized vanadia before further cracking over acidic sites in HZSM-5 catalyst.

The Kinetics of Catalytic Oxidation of 1-Butanethiol in a Gas Liquid System

In the present study the kinetics of liquid phase oxidation of light thiols using reformulated cobalt phthalocyanine based catalyst has been investigated in a semi batch bubble column reactor. 1-Butanethiol is chosen to represent thiols in lighter range of petroleum fractions like liquefied petroleum gas and light straight run naphtha. The study has shown that rate of catalytic oxidation of 1-butanethiol is linear at lower concentrations and of nonlinear nature at higher concentrations. A mechanism based rate expression has been obtained to explain this behavior and its parameters are estimated. The derived rate law is similar to Michaelis-Menten rate equation.

Catalytic Coprocessing of Delayed Coker Light Naphtha with Light Straight-run Naphtha/FCC Gasoline

Upgrading of delayed coker light naphtha (DCLN) is difficult due to its high diolefin and silicon content. Mixtures of light straight-run naphtha (LSRN) and DCLN fractions were hydrotreated in two stages over NiMo/Al2O3 and CoMo/Al2O3 catalysts (diolefin saturation followed by hydrodesulphurization (HDS). Naphtha fractions free of diolefins, olefins, sulfur, and silicon were produced, which are excellent feeds for naphtha isomerization. One-stage selective HDS tests were also conducted with blends of DCLN (up to 5 vol%) and fluid catalytic cracked (FCC) gasoline over CoMo/Al2O3. Diolefin-free products of <10 mg/kg sulfur could be produced with a research octene number (RON) loss of max. 3.

Catalytic Cracking Behavior of n-Heptane over HZSM-5 Catalyst

The catalytic cracking of n-heptane, which was selected as a model compound for the paraffin of light straight-run naphtha, was studied over HZSM-5 catalyst in a fixed-bed microreactor. Its catalytic behavior was compared with that of 1-heptene and the effects of hydrothermal treatment and catalyst carrier were evaluated. The results showed that compared with the cracking of 1-heptene, the concentration of hydrogen, methane, and ethane was much higher in the cracked gas obtained from the cracking of n-heptane. We concluded that this mainly originated from the monomolecular cracking pathway while the content of propylene and butylene in liquefied petroleum gas (LPG) was much lower. Upon hydrothermal treatment, the total amount of acid decreased sharply, especially the strong Br[o]nsted acid (Bacid) sites, leading to a steep decline in catalytic activity. This was accompanied by the improved propylene/propane and butylene/butane molar ratios in the products. Meanwhile, the ratio between the C3 and C4 products decreased, suggesting a decrease in the occurrence of monomolecular cracking. The carrier also significantly influenced the cracking behavior of n-heptane. We found that the presence of Lewis acid (Lacid) sites in the carrier improved the n-heptane conversion and promoted the bimolecular cracking pathway. Generally, compared with the olefin reactant, paraffin usually shows much lower reactivity and light olefin selectivity and, therefore, it is not a desirable feed for the catalytic cracking reaction over the zeolite catalyst for the purpose of light olefin production.

PETROCHEMICAL PROMOTERS IN CATALYTIC CRACKING

This study is based on the current scheme followed by a refinery with available Catalytic Cracking capacity to process new feedstocks such as Straight Run Naphtha and Naphthas from FCC. These feedstocks are of petrochemical interest to produce Ethane, Ethylene, Propylene, i-Butane, Toluene and Xylene. To evaluate the potential of these new streams versus the Cracking-charged Residues, it was performed a detailed chemical analysis on the structural groups in carbons [C1-C12] at the reactor product obtained in pilot plant. A catalyst with and without Propylene - Promoter Additive was used. This study analyzes the differences in the chemical composition of the feedstocks, relating them to the yield of each petrochemical product. Straight Run Naphthas with a high content of Naphthenes, and Paraffines n[C5-C12] and i[C7-C12] are selective to the production of i-Butane and Propane, while Naphthas from FCC with a high content of n[C5-C12]Olefins, i-Olefins, and Aromatics are more selective to Propylene, Toluene, and Xylene. Concerning Catalytic Cracking of Naphthas, the Additive has similar selectivity for all the petrochemical products, their yields increase by about one point with 4%wt of Additive, while in cracking of Residues, the Additive increases in three points Propylene yield, corresponding to a selectivity of 50% (ΔC3= / ΔLPG).

Catalytic Co-Processing of delayed coker light naphtha with other refinery gasoline streams

Upgrading of delayed coker light naphtha is very difficult due to its high diolefin and silicon content. Mixtures of light straight run naphtha and delayed coker light naphtha fractions were hydrotreated in two stages over NiMo/Al 2 O and CoMo/Al 2 O catalysts (diolefin saturation followed by hydrodesulphurization ). The results showed that naphtha fractions free of diolefins, olefins, sulphur and silicon can be produced with the two stage hydrogenation. These are excellent feeds for naphtha isomerization. One-stage selective hydrodesulphurization tests were also conducted with blends of coker naphtha (up to 5 vol%) and fluid catalytic crackers gasoline over CoMo/Al 2 O . Diolefin-free products of < 10 mg/kg sulphur could be produced with a research octane number loss of max. 3.

Combined isomerization of overhead cuts of straight-run naphtha and reformate

Technology was developed for combined isomerization of IBP-85°C overhead cuts of straight-run naphtha and reformate to reduce the benzene content in automotive gasolines. In comparison to the traditional technology, this technology ensures a benzene content below 0.7% and a 1–2-point increase in the octane number (ON) of commercial gasolines.

Modeling of pyrolysis of straight-run naphtha in a large-capacity type SRT-VI furnace

The problem of modeling pyrolysis of naphtha in a modern SRT-VI large-capacity furnace from ABB Lummus Global (USA) was examined. Curves of the yield of basic products as a function of the composition of the feedstock and pyrolysis regime were obtained with the experimental data and physicochemical characteristics of the process. The model is intended for predicting the composition of pyrolysis gas and controlling the pyrolytic process in an active plant.

直留ナフサおよびFCCガソリン中の硫黄化合物の分析

Sulfur-containing compounds in straight-run naphtha and catalytic-cracked gasoline were analyzed quantitatively using gas chromatography with a sulfur chemiluminescence detector. Pretreatment of the samples by open column chromatography and silver nitrate treatment were introduced to assign sulfur species. Commercial reagents, prepared standard samples and a commercial mass spectrum library were also utilized to assign the sulfur species. The sulfur content of naphtha was 242 ppm and 83 compounds were identified. Sulfur species consisted of 34 wt% of thiacycloalkanes, 38 wt% of thiols and sulfides, 12 wt% of thiophenes, 11 wt% of disulfides, and 5 wt% of unknown compounds. The sulfur content of gasoline was 154 ppm and 41 compounds were assigned. Sulfur species consisted of 46 wt% of thiophenes, 32 wt% of benzothiophenes, 14 wt% of thiols and sulfides, 4 wt% of thiacycloalkanes, 0.6 wt% of disulfides, 0.3 wt% of hydrogen sulfide and 3 wt% of unknown compounds. The combination of two types of pretreatment methods was effective for quantitative analysis of sulfur compounds contained in the distillate. The results of hydrodesulfurization of light distillate suggested that difficulty of hydrodesulfurization could be predicted from the composition of sulfur compounds in the distillates.

An antiknock additive of the new generation

An antiknock additive which is a mixture of an aromatic amine, an antioxidant, the straight-run naphtha cut of naphthene-aromatic base crude oil, and chloro-and isoparaffins, is proposed. The additive is given antiknock activity by passing it through a catalyst — manganese — at the boiling point and atmospheric pressure. In a concentration of 0.03–0.2 wt. %, the additive increases the motor octane number of low-octane motor fuels by 5–14 points.

Separation of Sulfur Compounds in Straight-Run Naphtha

Abstract Sulfur-containing compounds in straight-run naphtha were separated from coexisting hydrocarbons by means of open-column chromatography. Elution with hexane was continued after outflow of saturated hydrocarbons in the original sample, and aromatic hydrocarbons eluted gradually without any accompanying sulfur-containing compounds. When aromatic hydrocarbons ceased to be observed in the effluent, hexane was changed to benzene. A mixture of thiophenes, disulfides, and thiols then began to elute, followed ultimately by a mixture of sulfides and thiacycloalkanes. The obtained sulfur-containing compounds contained very small amounts of hydrocarbons other than the elution solvent, and their mass spectra could be observed by means of gas chromatograph-mass spectrometry.

An Appraisal of Hydrocarbons Conversion Reactions During Naphtha Reforming Process

A pilot plant study was performed to understand the reforming reactions network using a blend of straight run and hydrocracked naphtha. Three major classes of reactions that occurred during reforming were naphthenes dehydrogenation, n-paraffins cracking, and dehydrocyclization. The increase in aromatics was attributed to paraffin dehydrocyclization, the selectivity of which increases with carbon number. Aromatic contents were increased, while other hydrocarbons were decreased and converted to aromatics. Naphthenes were converted to aromatics of the same carbon number. The results indicated a drop in aromatic content as the catalyst deactivated with an increase in time on stream.

Infrared spectrophotometry, a rapid and effective tool for characterization of direct distillation naphthas

The characterization of naphtha obtained by direct distillation of medium and heavy crude oils is often limited by the low yield of these fractions. Gas chromatography is a technique that allows a complete determination of the chemical composition of these fraction. However, the prediction of properties such as octane rating and RVP from chromatographic data is a difficult task because there are not adequate models to predict the interaction of the different components, and particularly in the case of heavier fractions, there are some problems for the complete separation of components under the gas chromatographic conditions. The IR technology constitutes a rapid and effective tool to predict several properties of naphtha from the correlation of the spectrum in the infrared area and the properties. In this study, prediction models were developed in a Petrospec Cetane 2000 analyzer, in order to predict in a fast and simple way, the density, the antiknock index and the aromatic content of straight run naphtha obtained in a standard crude oil distillation unit. The equipment used was designed in the factory for the exclusive characterization of medium distillation and not for lighter fractions therefore this work constitutes an innovation given the extensive applications of this type of analyzers.

Liquid-Vapor Phase Equilibria in Binary and Ternary Subsystems Constituted by Pyrocondensate Components from the Pyrolysis of Straight-Run Naphtha

Liquid-vapor equilibrium in the binary subsystems of the ethylbenzene-o-xylene-α-methylstyrene-p-vinyltoluene-dicyclopentadiene-indene system was predicted using UNIFAC group model and studied experimentally. To assess the reliability of parameters, the liquid-vapor equilibrium was studied experimentally in the ternary systems and compared with the calculated data.

Effect of high-temperature steam treatment of high-silica zeolites of the ZSM-5 type on their acidity and selectivity of formation of lower olefins from straight-run naphthas

The effect of high-temperature steam treatment of high-silica zeolites of the ZSM-5 type on their acidity and selectivity of formation of lower olefins from straight-run naphthas was studied.

Transformations of Straight-Run Naphthas on Indium-Modified Pentasils

The influence exerted by the procedure of introducing indium into high-silica zeolite of the Pentasil type on its acid properties and catalytic activity in transformation of straight-run naphthas into lower olefins and aromatic hydrocarbons was studied.

Development of pyrolysis catalysts based on barium chloride for industrial use

The catalysts of pyrolysis of straight-run naphtha, platforming raffinate, and thermal cracking naphtha, based on barium chloride, were developed. The strength characteristics of preformed catalysts with addition of graphite, alkylamide of synthetic fatty acid (SFA), phenol-furan resin, and clay were studied.

Conversion of Straight-Run Naphtha Cuts on Zeolite-Containing Catalysts

An important problem in the oil-refining industry is exhaustive refining of hydrocarbon feedstock into high–octane components of motor fuels using destructive catalytic processes. This is due to the limited resources of crude oil and gas feedstock, the increasing demand for automotive gasolines, and the necessity of improving the environment in industrial regions.