Crude Oil Distillation Research Articles

Cu determination in crude oil distillation products by atomic absorption and inductively coupled plasma mass spectrometry after analyte transfer to aqueous solution

Cu was determined in a wide range of petroleum products from crude oil distillation using flame atomic absorption spectrometry (FAAS), electrothermal atomic absorption spectrometry (ETAAS) and inductively coupled plasma mass spectrometry (ICP-MS). Different procedures of sample preparation were evaluated: (i) mineralization with sulfuric acid in an open system, (ii) mineralization in a closed microwave system, (iii) combustion in hydrogen–oxygen flame in the Wickbold's apparatus, (iv) matrix evaporation followed by acid dissolution, and (v) acidic extraction. All the above procedures led to the transfer of the analyte into an aqueous solution for the analytical measurement step. It was found that application of FAAS was limited to the analysis of the heaviest petroleum products of high Cu content. In ICP-MS, the use of internal reference method (with Rh or In as internal reference element) was required to eliminate the matrix effects in the analysis of extracts and the concentrated solutions of mineralized heavy petroleum products. The detection limits (in original samples) were equal to, respectively, 10, 86, 3.3, 0.9 and 0.4 ng g − 1 in procedures i–v with ETAAS detection and 10, 78, 1.1 and 0.5 ng g − 1 in procedures i–iii and v with ICP-MS detection. The procedures recommended here were validated by recovery experiments, certified reference materials analysis and comparison of results, obtained for a given sample, in different ways. The Cu content in the analyzed samples was: 50–110 ng g − 1 in crude oil, < 0.4–6 ng g − 1 in gasoline, < 0.5–2 ng g − 1 in atmospheric oil, < 6–100 ng g − 1 in heavy vacuum oil and 140–300 ng g − 1 in distillation residue.

Comparison Study for the Distribution of Organo-Sulfur Containing Compounds of Two Kuwaiti Crude Oil Distillates

This paper deals with the comparison, analysis, and characterization of two Kuwaiti crude oil samples received from different origins. (Burgan and Al-Wafra oil fields). Systematic analysis was conducted for API gravity, sulfur content, metal content, and viscosity. The representative samples of the two Kuwaiti crude oils were fractionated into naphtha (IBP–170○C), kerosene (170–265○C), medium gas oil (265–355○C), and heavy gas oil (355–550○C) using an 80 L capacity autodistillation unit “AUTODEST-800” according to ASTM D2892 and ASTM D5236. Particular attention was paid to study the distribution of various types of sulfur compounds in each of these wide cuts, which was qualitatively and quantitatively estimated by capillary gas chromatography equipped with a sulfur chemiluminescence detector, which is suitable for a wide range of sulfur systems. The fingerprinting obtained from the analysis of GC-SCD showed different families of organo-sulfur compounds in crudes, including mercaptans, sulfides, thiophenes, benzothiophenes, dibenzothiophene, benzonaphtothiophene, and their alkyl derivatives. From the analyses the behavior and distribution of the refractory and unrefractory sulfur compounds in the two Kuwaiti crude oils can now be easily followed.

Thermodynamic analysis of crude oil distillation systems

This work deals with a thermodynamic analysis of crude oil distillation systems to study energy and exergy efficiencies for system analysis, performance evaluation and optimization. In this regard, a new analysis methodology is proposed, and the SimSci/PRO II (2000) is employed as a simulation package for the required parametric studies, particularly to study the effects of the distillation column temperatures and pressures on the efficiencies. The simulations are carried for the operating conditions of the model. It is found that the total irreversibility losses are 608 MW for a flow rate of 507 kg s−1 [e.g. 56% by the Atmospheric Distillation Unit (ADU), 26% by the Vacuum Distillation Unit (VDU) and 18% by the heaters]. The highest irreversibility losses occur in the ADU as the main separation takes place there. Of the losses, 6.2% are due to chemical exergy losses associated with the separation process itself. The rest of the losses are due to the physical exergy losses mainly because of the temperature difference. The energy efficiencies are 0.497 for the ADU, 0.579 for the VDU and 0.519 for the overall system. The exergy efficiencies are 0.433 for the ADU, 0.501 for the VDU, 0.821 for Heater 1, 0.956 for Heater 2 and 0.233 for the overall system. The overall efficiency is not equal to the product of the components efficiencies. Copyright © 2005 John Wiley & Sons, Ltd.

Effect of reference state on exergy efficiencies of one- and two-stage crude oil distillation plants

In this paper we deal with the effects of varying reference temperature on the exergy efficiencies of one- and two-stage crude oil distillation units. Such units essentially consist of the crude oil heating furnace, the distillation column and a network of heat exchangers. Since the exergy efficiency is a key parameter to see how well the system is performing, we undertake a study on the influence of the reference temperature on such efficiencies. In this regard, a commercial software package, SimSci/PRO II program is used for the calculations. The results show that increasing reference temperature decreases the exergy efficiency in both one- and two-stage crude oil distillation systems and also increases the difference between the exergy efficiencies of both systems. Therefore, the exergy losses increase in the crude oil distillation systems.

Primary Crude Refining Unit at Komsomol'sk Refinery

A single–tower scheme for atmospheric distillation of crude oil with preliminary separation of naphtha vapors after heating the crude with heat from waste streams is implemented. The unit's equipment corresponds to the current world level. The specific power consumption for refining crude in the new unit corresponds to the power consumption of the best foreign analogs.

DNA adduct formation and physiological effects from crude oil distillate and its derived base oil in isolated, perfused rat liver.

A distillate, D431, originating from Venezuelan heavy crude oil and a severely hydro-treated base oil, BO100, derived from this distillate, were tested for DNA adduct formation capacities and overall impact on liver functions. D431 had earlier showed DNA adduct formation in vitro but not in vivo in the rat. In this study, isolated rat liver perfusions were performed to elucidate whether the lack of DNA adducts in vivo was because of lack of uptake or metabolism. The oils were extracted with dimethyl sulfoxide and the extracts added to the perfusion system. Bile production, lactate metabolism and perfusate flow through the organ, which are parameters that reveal the condition of the liver, were continuously monitored. Samples of liver were collected once every hour during perfusion for DNA adduct analysis with (32)P-HPLC. The results for the distillate D431 showed that the production of bile and metabolism of lactate decreased while DNA adduct formation increased with time. The DNA adduct pattern formed in the D431-treated livers was similar to that found earlier in in vitro studies performed on calf thymus DNA (CT-DNA). In the case of DNA adduct formation, virtually no difference with dose was seen, suggesting that perhaps a point of saturation of, for instance, enzymatic systems was reached. The results for base oil BO100 showed no significant difference regarding bile production, lactate metabolism and DNA adduct formation when compared with the control, indicating no toxic or genotoxic activity.

Exergy Analysis of Single- and Two-Stage Crude Oil Distillation Units

In a refinery distillation plant, there are many components of interest to be analyzed thermodynamically, e.g., the crude oil heating furnace, the distillation column and a network of heat exchangers. Previous studies showed that the highest exergy losses occur when there is a heat transfer process especially in the crude oil heating furnace where high quality fuel is used to heat the crude oil, which is a low quality duty, beside the high temperature difference. Therefore, it is proposed in this work to perform distillation in two stages rather than one to reduce heat duty of the heating furnace and thus reducing irreversible losses. In this paper, energy and exergy analyses of a traditional one-stage crude oil distillation unit and a newly proposed two-stage crude oil distillation unit are conducted to study energy and exergy efficiencies of these units and determine the exergy losses. The results are compared for both one- and two-stage distillation units. In this regard, a commercial software package, SimSci/PRO II program is used to carry out both energy and exergy calculations. It is found that the overall exergy efficiencies for single- and two-stage distillation units are 14.0% and 31.5%, respectively. The proposed two-stage distillation unit shows 43.8% decrease in the overall exergy losses and 125% increase in the overall exergy efficiency.

Expert system of a crude oil distillation unit for process optimization using neural networks

An expert system of crude oil distillation unit (CDU) was developed to carry out the process optimization on maximizing oil production rate under the required oil product qualities. The expert system was established using the expertise of a practical CDU operating system provided by a group of experienced engineers. The input operating variables of the CDU system were properties of crude oil and manipulated variables; while the system output variables were defined as oil product qualities. The knowledge database of the CDU operating model can be built using the input–output data with an approach of artificial neural networks (ANN). The built ANN model can be applied on predicting the oil product qualities with respect to the system input variables. In addition, a design of experiment was implemented to analyze the effect of the system input variables on the oil product qualities. Optimal operating conditions were then found using the knowledge database with an optimization method according to a defined objective function. The built expert system can provide on-line optimal operating information of the CDU process to the operators corresponding to the change of crude oil properties.

Hematological, Biochemical and Histological Effects of Prolonged Exposure to 1-Hexane in Albino Rats

N-Hexane is a chemical solvent produced during the cracking and fractional distillation of crude oil and is used widely in industry (paints, varnishes, inks, plastics and rubber). In addition, n-hexane is a major component of benzine and glue which are often sniffed to induce euphoria. The present study aimed to evaluate the effects of prolonged exposure to n-hexane. The experimental animals (albino rats) were dosed with 5 mg/kg n-hexane dissolved in olive oil subcutaneously once daily, 6 days/week for 8 weeks. The hematological findings revealed marked pancytopenia (anemia, leucopenia, thrombocytopenia) which could be attributed histologically to necrosis and diffuse fibrosis in bone marrow. Hexane-induced neurotoxicity was in the form of mild hemorrhage in brain cortex and could explain the marked decrease in locomotor activity among hexane treated group. The lung tissue revealed moderate hemorrhage with lymphocytic and macrophage infiltration. There were patchy areas of focal hepatocellular necrosis. The cardiac muscle revealed fragmentation that could explain derangement of intracellular ions. There was a significant reduction of myocardial contents of magnesium, potassium and zinc in treated group compared to control group that might have influence upon myocardial excitability. The serum concentration of these elements revealed insignificant difference between treated and control groups. The cardiotoxicity and neurotoxicity of n-hexane could explain mortalities encountered among the treated group throughout the study. The results of the study support the guidelines to minimize occupational exposure 10 1-hexane and to fight glue, benzene and other solvent abuse.

Oil/Suspended Particulate Material Interactions and Sedimentation

The interactions of physically dispersed oil droplets with suspended particulate material (SPM) can be important for the transport of bulk quantities of spilled crude oil and polycyclic aromatic hydrocarbons (PAH) to subtidal sediments. The literature regarding oil/SPM interactions is reviewed, and results from whole-oil droplet/SPM interaction kinetics and pure-component (Prudhoe Bay crude oil distillate cut) equilibrium partitioning experiments are presented. The effects of oil type, SPM characteristics, and salinity on the interaction rates are examined, and the importance of whole-oil droplet/SPM interactions on particle agglomeration and settling behavior are discussed. Whole-oil droplet/SPM interactions are retarded as oil droplet dispersion into the water column is inhibited by oil viscosity increases due to evaporation weathering and water-in-oil emulsification. Compared to whole oil droplet/SPM interactions, dissolved-component/SPM adsorption is not as significant for transport of individual components to sediments. The information presented in this paper can be used to augment computer-based models designed to predict oil-spill trajectories, oil-weathering behavior, and spilled oil impacts to the marine environment.

High-resolution field desorption/ionization fourier transform ion cyclotron resonance mass analysis of nonpolar molecules.

We report the first field desorption ionization broadband high-resolution (m/Deltam(50%) approximately 65 000) mass spectra. We have interfaced a field ionization/field desorption source to a home-built 9.4-T FT-ICR mass spectrometer. The instrumental configuration employs convenient sample introduction (in-source liquid injection) and external ion accumulation. We demonstrate the utility of this configuration by generating high-resolution positive-ion mass spectra of C(60) and a midboiling crude oil distillate. The latter contains species not accessible by common soft-ionization methods, for example, low-voltage electron ionization, electrospray ionization, and matrix-assisted laser desorption/ionization. The present work demonstrates significant advantages of FI/FD FT-ICR MS for analysis of nonpolar molecules in complex mixtures.

A Comprehensive Evaluation of High Viscous Crude Oil from Shuguang No. 1 Zone of Liaohe Oil Field

The high viscous crude oil from Shuguang No. 1 zone of Liaohe oil field has the characteristics of high density (ρ 20 = 0.9977 g cm−3), great viscosity (ν 100 = 1223.9 mm2 s−1) and high pour point (48°C), which are similar to those of the residue distillation of general crude oils. It contains no gasoline distillation and the diesel oil fraction yield is just 7.19%. It is often used as fuels after emulsification. But this oil is so vicious that it cannot be atomized uniformly and burned fully. In order to make full use of it, this kind of high viscous crude oil has been evaluated comprehensively and the properties of its various distillations are analyzed respectively. The results indicate that this crude oil contains less wax, but more resins and asphaltene, which belongs to low-sulfur naphthene-base crude oils and it is the suitable material to produce high-quality paving asphalt. Based on its characteristics, the optimum processing scheme is put forward and the high-quality paving asphalt is produced by using the distillation higher than 350°C.

Content of Light Cuts in Atmospheric Resid. Effect of Different Factors

According to data on operation of primary crude oil distillation units, the content of light cuts in atmospheric resid can reach 17—20%, primarily due to deviation of the process parameters from the rated parameters. Optimization of operation of equipment and the process parameters in consideration of all factors determining the efficiency of fractionation will reduce the content of light cuts in straight–run atmospheric resid to 5—7% without additional capital outlays.

Power Supply and Energy Conservation in Fractional Distillation of Crude Oil

Different schemes of connecting distillation towers are examined: from separating subsystems with coupled heat flows to separating subsystems with linkages of towers for distillate or residue. The causes that prevent implementation of separation schemes with connected heat flows as subsystems with minimum power consumption for separation of multicomponent mixtures are revealed. A system is proposed for separation of crude oil as a multicomponent mixture into seven products with minimum consumption of primary energy resources due to maximum recovery and utilization of secondary energy resources. The use of combined separation schemes together with optimum subsystems for supplying and recovering thermal energy will eliminate terminal coolers—after—coolers and cooling agents.

Practical approach to measure the relative activity of heterogeneous catalysts

This paper introduces a simple, practical approach to measure the relative activity of various heterogeneous catalysts using electrical measurements. The applicability of this practical method was demonstrated on four commercial catalysts; a potassium-promoted iron oxide used for the dehydrogenation of ethyl benzene to produce styrene, a commercial hydrotreating catalyst used to remove sulfur and nitrogen from crude oil distillates such as gasoline or gas oil, a basic alumina that catalyzes the hydrolysis of halogenated hydrocarbons, and an unidentified catalyst from a major supplier. The electrical resistances of fresh, used and regenerated catalyst samples were measured on single particles, and specific conductivities were calculated. The difference between the conductivity of fresh and spent catalysts was found to be significant (1–5 orders of magnitude), while the conductivities of the regenerated samples were essentially identical to that of the fresh catalyst. Resistance measurements were also conducted in packed beds of the hydrotreating and basic alumina catalysts, and the concept of apparent specific conductivity was defined. The change in specific conductivity measured on single particles of fresh and regenerated catalysts, and the change in apparent specific conductivity measured in a packed bed of the same catalysts were very close. The simplicity of this new method renders it to be a potential sensitive on-line prediction method of relative catalyst activity.

Softeners for Rubber and Corrosion-Resistant Coatings Based on Shale and Petroleum Raw Materials

A broad spectrum of softeners for vulcanized rubber and corrosion-resistant materials are obtained by mechanical mixing of kerogen shale (Kerogen-701) with commercial products of petroleum refining and shale chemistry such as oil tar, bitumens BND 90/130 and G, softener A-10, residue of atmospheric distillation of crude shale oil boiling above 350°C, and also by thermal treatment of the indicated mixtures at 360-400°C.

Planning and scheduling models for refinery operations

The main objective of this work is to discuss planning and scheduling applications for refinery operations. Firstly, the development of a nonlinear planning model for refinery production is presented. The model is able to represent a general refinery topology and allows the implementation of nonlinear process models as well as blending relations. Considering the market limitations for each oil derivative usually supplied by the refinery, the optimization model is able to define new operating points, thus increasing the production of more valuable products, while satisfying all specification constraints. Real-world applications are developed for the planning of diesel production in the RPBC refinery in Cubatão (SP, Brazil) among others. The optimization results were compared to the current situation, where no computer algorithm is used and the stream allocation is made based on experience, with the aid of manual calculations. The new operating point represents an increase of several million dollars in annual profitability. The second part of the work addresses scheduling problems in oil refineries that are formulated as mixed integer optimization models and rely on both continuous and discrete time representations. The problem of crude oil inventory management that involves the optimal operation of crude oil unloading from pipelines, transfer to storage tanks and the charging schedule for each crude oil distillation unit will be discussed. Furthermore, the paper will consider the development and solution of optimization models for short-term scheduling of a set of operations that includes: product receiving from processing units, storage and inventory management in intermediate tanks, blending in order to attend oil specifications and demands, and transport sequencing in oil pipelines. Important real-world examples on refinery production and distribution are reported: the diesel distribution problem at RPBC refinery and the production problems related to the fuel oil/asphalt and LPG areas of the REVAP refinery in São José dos Campos (SP, Brazil), which produces approximately 80% of the national consumption.

Crude Oil Wax Crystallization. The Effect of Heavy n-Paraffins and Flocculated Asphaltenes

The influence of heavy linear alkanes concentration on the wax crystallization tendency or wax appearance temperature (WAT) of a paraffinic crude oil and on a paraffin inhibitor effectiveness was evaluated by means of polarized light microscopy. A crude oil insensitive to the addition of wax inhibitors was fractionated into its hydrocarbon class fractions. Virgin crude oil distillation, deasphaltation of the 385 °C+ residue, HPLC separation of the heavy saturated hydrocarbons, and molecular sieves adduction enabled us to isolate the linear paraffins fraction with a carbon distribution of more than 24 atoms (nC24+ paraffins). A synthetic crude was prepared by mixing all separated fractions, except nC24+ paraffins, and the effect of this fraction concentration was evaluated by its controlled addition to the synthetic crude followed by cloud point measurements of all doped samples. The influence of this hydrocarbon class family concentration on a maleic anhydride copolymer derivative paraffin inhibitor (MAC)...

Industrial application of Wavelet Transform to the on-line prediction of side draw qualities of crude unit

In this paper, Wavelet Transform is applied to improve the on-line prediction of crude oil distillation (COD) qualities. First, the wavelets-based multi-scale analysis method was applied to treat the process data effectively. According to their unique characteristics with multi-scale Wavelet Transform, different variations are detected and modified, such as steps, peaks, noises, abnormal sudden changes, and so on. Using the process data with noises discarded and abnormal sudden changes treated effectively, the COD quality prediction can be sure of safety and high accuracy. Next, for some COD units on-line quality analyzers are available, and a new correcting strategy is taken in this paper to give effective update. The update is accomplished based on process data trends extraction. At last, the data processing and the on-line update strategy are introduced to a prediction system of COD product qualities to improve its prediction accuracy. The improved prediction system has been applied in a real plant, and the results are satisfactory.

Effects of Mitigating Fouling on the Energy Efficiency of Crude-Oil Distillation

An analysis was performed to determine the effects of fouling of the preheat train on the energy efficiency of a typical crude-distillation unit with a capacity of 100,000 bbl/day. A spreadsheet analysis was developed to calculate the thermal duty for each of the heat exchanger groups that heat the crude oil from ambient conditions to the distillation temperature. A fouling-rate model developed in a previous study was applied to calculate the fouling resistance as a function of time. Improvements in the energy efficiency were analyzed for different mitigation scenarios. The analysis shows economic incentives for new and improved techniques for mitigating fouling of the preheat train.