Distillation Characteristics Research Articles

Steady-state experimental studies on a multi-effect thermal regeneration solar desalination unit with horizontal tube falling film evaporation

A special desalinization unit which utilizes solar or waste energy has been developed and tested indoors. In thisunit, a relatively large fraction of latent and sensible heat of condensation along with brine is successfully recycled and utilized. It is used to preheat and evaporate the feedstock due to the multi-effect thermal regenerative process. Since the falling film evaporation is used and the system posses the characteristics of flash distillation and vapor compression, the thermal performance of the system is improved greatly. As a result of the simulation of the unitoperating with a solar system under practical weather conditions, the yield is about two times greater than that of a conventional single basin solar still with the same thermal energy input. The transient-state performance of the unit, the relationships among the operating temperature, feedstock flow rate and the productivity are presented. Other factors which influence the freshwater yield are also discussed.

Ethanolysis of used frying oil. Biodiesel preparation and characterization

The transesterification reaction of used frying oil by means of ethanol, using sodium hydroxide, potassium hydroxide, sodium methoxide, and potassium methoxide as catalysts, was studied. The objective of the work was to characterize the ethyl esters for its use as biodiesels in compression ignition motors. The operation variables used were ethanol/oil molar ratio (6:1–12:1), catalyst concentration (0.1–1.5 wt.%), temperature (35–78 °C), and catalyst type. The evolution of the process was followed by gas chromatography, determining the concentration of the ethyl esters at different reaction times. The biodiesel was characterized by its density, viscosity, flash point, combustion point, cold filter plugging point, cloud and pour points, Conradson carbon residue, characteristics of distillation, cetane index and high heating value according to ISO norms. The biodiesel with the best properties was obtained using an ethanol/oil molar ratio of 12:1, potassium hydroxide as catalyst (1%), and 78 °C temperature. The density, viscosity, cetane index, Conradson carbon residue and calorific power of the biodiesel obtained had values close to those of a no. 2 diesel. On the contrary, the cold filter plugging point, and cloud and pour points are higher than the conventional diesel fuel. Although higher, flash and combustion points fulfil the norms for ethyl esters derived from vegetable oils. In consequence, the final product obtained had very similar characteristics to a no. 2 diesel oil, and therefore, these ethyl esters might be used as an alternative to fossil fuels. The two-stage transesterification was better than the one-stage process, and the yields of ethyl esters were improved 30% in relation with the one-stage transesterification.

The effect of increased branched-chain amino acid transaminase activity in yeast on the production of higher alcohols and on the flavour profiles of wine and distillates

In Saccharomyces cerevisiae, branched-chain amino acid transaminases (BCAATases) are encoded by the BAT1 and BAT2 genes. BCAATases catalyse the transfer of amino groups between those amino acids and alpha-keto-acids. alpha-Keto-acids are precursors for the biosynthesis of higher alcohols, which significantly influence the aroma and flavour of yeast-derived fermentation products. The objective of this study was to investigate the influence of BAT-gene expression on general yeast physiology, on aroma and flavour compound formation and on the sensory characteristics of wines and distillates. For this purpose, the genes were overexpressed and deleted in a laboratory strain, BY4742, and overexpressed in an industrial wine yeast strain, VIN13. The data show that, with the exception of a slow growth phenotype observed for the BAT1 deletion strain, the fermentation behaviour of the strains was unaffected by the modifications. The chemical and sensory analysis of fermentation products revealed a strong correction between BAT gene expression and the formation of many aroma compounds. The data suggest that the adjustment of BAT gene expression could play an important role in assisting winemakers in their endeavour to produce wines with specific flavour profiles.

Formation Characteristics of Diesel Nanoparticles

Nanoparticles formed in motor vehicle exhaust have received increasing attention due to their potential adverse health effects. But there are a lot of uncertain points for chemical properties and formation mechanisms of diesel nanoparticles. The objective of this study was to characterize nanoparticles emitted from a light-duty diesel engine operated on a dynamometer. Diesel nanoparticles which typically range in diameter from 3 to 30 nm were observed only under idling, high load and deceleration conditions. The formation characteristics of diesel nanoparticles under idling and high load conditions depended mainly on fuel distillation characteristics and sulfur content in fuel, respectively while fuel-cut control of fuel injection in deceleration process had a strong influence on those under deceleration condition. Nanoparticles under idling and deceleration conditions were composed mainly of high boiling point hydrocarbons (heavy hydrocarbons) in fuel and/ or lubricating oil and those under high load conditions consisted of sulfuric acid. The formation characteristics of diesel volatile nanoparticles was controlled by number concentration of accumulation mode particles.

Biodiesel from Used Frying Oil. Variables Affecting the Yields and Characteristics of the Biodiesel

A study was performed of the transesterification reaction of used frying oil by means of methanol, using sodium hydroxide, potassium hydroxide, sodium methoxide, and potassium methoxide as catalysts. The objective of the work was to characterize the methyl esters for use as biodiesels in compression ignition motors. The operation variables used were methanol/oil molar ratio (3:1−9:1), catalyst concentration (0.1−1.5 wt %), temperature (25−65 °C), and catalyst type. Also, experiments in two stages of reaction, with separation of the glycerol in the first stage, were carried out. The evolution of the process was followed by gas chromatography, determining the concentration of the methyl esters at different reaction times. The biodiesel was characterized by its density, viscosity, high heating value, cetane index, cloud and pour points, characteristics of distillation, flash and combustion points, saponification value, and iodine value according to ISO norms. The biodiesel with the best properties was obtain...

Effect of the hydrocarbon molecular structure in diesel fuel on the in-cylinder soot formation and exhaust emissions

Evaluations of diesel fuel effects on combustion and exhaust emissions in single-cylinder direct-injection diesel engines led to the unexpected result that a Swedish ‘class 1’ fuel generated more particulate matter (PM) than a fuel denoted ‘improved’, even though ‘class 1’ fuel had much lower distillation temperatures, aromatic concentration, sulphur level, and density than the ‘improved’ fuel. Little differences were observed in the combustion characteristics between these fuels, but detailed compositional analyses showed that ‘class 1’ fuel contains higher levels of cyclic and/or branched paraffins. Subsequent investigations in a laboratory flow reactor showed that ‘class 1’ fuel produces more soot precursors such as benzene and acetylene than the ‘improved’ fuel. In addition, experiments in a low-pressure laminar flame apparatus and shock tube with model (single-molecule) paraffin fuels showed that isoparaffins and cycloparaffins generate more soot precursors and soot than n-paraffins do. These results strongly suggested that the effect of molecular structure on exhaust PM formation should be more carefully examined. Therefore, a new series of investigations were performed to examine exhaust emissions and combustion characteristics in single-cylinder engines, with well-characterized test fuels having carefully controlled molecular composition and conventional distillation characteristics and cetane numbers (CNs). These investigations revealed the following. Firstly, under low and medium loads, cycloparaffins (naphthenes) have a higher PM formation tendency than isoparaffins and n-paraffins. Under high-load conditions, however, the paraffin molecular structure has a very small effect. Secondly, a highly n-paraffinic fuel does not yield PM reductions as high as expected, due to its high CN and corresponding shorter ignition lag, which initiates combustion under a state of insufficient fuel-air mixing. This finding was corroborated by laser-induced incandescence analyses. Thirdly, the lowest PM emissions were observed with a paraffinic fuel containing 55 per cent isoparaffins and 39 per cent n-paraffins. Fourthly, aromatics give higher soot and PM levels than paraffins do at high and medium load conditions. Smaller differences are observed at lower speeds and loads. Fifthly, the best fit to the PM emissions was obtained with an equation containing the regression variables CN, aromatic rings, and naphthene rings. This expression of the fuel effects in chemical terms allows well-to-wheel analyses of refining and vehicle impacts resulting from molecularly based fuel changes.

Feasibility Studies for Conventional Refinery Distillation with a (1:1) w/w of a Biocrude Blend with Petroleum Crude Oil

Biocrude produced by the catalytic cracking of plant seed oil has the potential for use as a substitute of petroleum crude oil. The distillation characteristics of a biocrude blend prepared by mixing 50 wt % of Oil India Limited (OIL) petroleum crude with the biocrude prepared from the methyl esters of Mesua ferrea L. seed oil are reported in this paper. More than 63% of the distillate can be recovered from the blend at atmospheric pressure, compared to 43% for the OIL crude. The recovery of aviation turbine fuel (JP-8), which normally has a boiling range of 175−250 °C was determined to be much higher: 26% in biocrude and 22% in the blend, compared to 16% for the OIL crude alone. This finding is significant, considering the increased demand for air transportation fuel. Blending shows great economic promise. Using vacuum distillation, the product recovered is ∼89% for the blend, whereas this recovery is only 76% for the OIL crude. The fractions obtained from blend distillation have characteristics that are similar to those of the petroleum crude. However, some additional treatment may need to be undertaken to reduce the stickiness and odor of the blended crude.

1192. 原子ビーム状に蒸発させた放射化金属廃棄物の分留特性の数値解析

1192. 原子ビーム状に蒸発させた放射化金属廃棄物の分留特性の数値解析

ジュラルミンの分留特性

For the separation of radionuclide from the radioactive metallic waste generated by the decommissioning of nuclear facilities, a new method combined with the distillation and laser separation is being developed. The characteristics of fractional distillation for duralumin (Aluminum alloy 7075: Al-5.6Zn-2.5Mg-1.6Cu-0.25Cr) are studied experimentally and theoretically for the first step. In the experiment, the duralumin (378.7 mg) is heated to 1773 K with the rate of 200 K/h and vaporized. The ion current of its components within the vapor is measured using quadrupole mass spectrometer. In the simulation, the vaporization rate of the components from the melt is calculated by using the Langmuir's equation and the Henry's law. The results of the simulation agree well with the experimental ones, and it is indicated that Al, Mg and Zn could be fractionated from duralumin.

Numerical study of the coupled heat and mass transfer in membrane distillation

In order to deepen the understanding of the permeate characteristics of membrane distillation considering heat and mass transfers and concentration polarisation, a fully predictive mathematical model was developed. The first part that is devoted to the natural heat and mass transfer in the rectangular cavity, states the problem in Cartesian coordinates system, involves the use of a control-volume method and solves the full vorticity transport equation together with the stream function, mass and energy equations. The temperature fields and streamlines are plotted for various geometrical conditions to show some of the flow field characteristics. The second part was set up to simulate the phenomenon present in the membrane distillation process. The mass transfer was described with combined Knudsen and Maxwell-Stefan equations and coupled to the simultaneous heat transfer. The effect of parameters such as thickness of cavity, temperature and feed flow rate were investigated. The results were compared with the available data and the agreement is satisfactory.

Extractive Distillation: A Review

Extractive distillation is more and more commonly applied in industry, and becomes an important separation method in chemical engineering. This paper provides an in‐depth review for extractive distillation. Separation sequence of the columns, combination with other separation processes, tray configuration and operation policy are included in process of extractive distillation. Since the solvent plays an important role in the design of extractive distillation, such conventional and novel separating agents as solid salt, liquid solvent, the combination of liquid solvent and solid salt, and ionic liquid are concerned. The prominent characteristics of extractive distillation is that one new solvent with high boiling‐point, i.e. separating agent, is added to the components to be separated, so as to increase their relative volatility. Selection of a suitable solvent is fundamental to ensure an effective and economical design. CAMD as a useful tool is applied for screening the solvents and thus reducing the experimental work. Theories from molecular thermodynamics, which can interpret the microscale mechanism of selecting the solvents, are also collected. To accurately describe the extractive distillation process, mathematical model is necessary. There are two types of mathematical models to simulate extractive distillation process, i.e. equilibrium (EQ) stage model and non‐equilibrium (NEQ) stage model. The EQ stage model as an old method is widely used, but the NEQ stage model should be pay more attention. In the end comparison of extractive distillation and adsorption distillation, both of which belong to special distillation suitable for separating close boiling point or azeotropic components, is done, and it is shown that extractive distillation is more advantageous.

Distillation of Multicomponent Mixtures of Higher Aliphatic Acids in Thermally Coupled Distillation Systems

A method is proposed to calculate the characteristics of distillation of multicomponent mixtures of higher aliphatic acids in distillation systems with reversible mixing of flows and coupled heat flows. The method is based on the use of the Underwood equations and the Thiele–Geddes method for independently determining the concentrations. Application of the method is illustrated by the example of calculating the characteristics of distillation of a mixture of coconut oil fatty acids into four fractions (C6–C10, C12, C14, and C16–C18 acids) in a system containing three columns, one reflux condenser, and two reboilers.

廃棄プラスチック再生残さ混合油における着火性評価｀＊´―第２報 セタン指数についての考察―

In Part 1, to clarify the usability of residual oil reclaimed from waste plastics as diesel fuel, the authors evaluated the correlation between the result of FIA ignition test and the calculation result of JIS K2204 Cetane Index.In this report, furthermore, referring to also the fuel density and the distillation characteristics of marine diesel oil, the authors considered the JIS K2204 and the JIS K2280 Cetane Index from ignition characteristics standpoint.

Oil from Pistachia Palestine as a fuel

In this study Pistachia Palestine (PP) oil was extracted and tested for its heating value, flash point and distillation characteristics. The oil was mixed with diesel fuel in different fraction and the heating value and flash points were obtained. The oil and diesel fuel was characterized by the measurement of their densities and viscosities. The results obtained showed that the oil produced from PP has the potential to act as a fuel or even an additive to diesel fuel. The study reveals the effect of PP oil–diesel fuel blends on the performance of indirect diesel engine (type Lister 8/1). The PP oil–diesel fuel blends were used in test engine operations with a wide range of engine speed at full load condition. Successful results were obtained without any engine modifications. It was also shown that the addition of PP oil to the diesel fuel decreases both the brake power and thermal efficiency of the test engine and increases the brake specific fuel consumption. This is due to the lower heating value of the PP oil compared to diesel fuel.

기계식 탄화로와 재래식 토요를 이용하여 제조한 죽초액의 이화학적 특성: 식품처리제로서의 특성

벌채 직후의 신선한 왕대(Phyllostachys bambuoides sieb. et zucc.)를 기계식 탄화로와 재래식 토요를 이용하여 탄화 시키고 여기에서 발생하는 기체를 100℃ 전후에서 냉각시켜 얻은 각각의 조죽초액을 12개월간 정치하여 타르성분을 분리한 다음 중간부위를 취하여 죽초액의 일반특성과 성분조성을 조사하였다. 기계식 죽초액은 비중, 투과도, 굴절율 및 점도가 각각 1.008, 89.05%, 1.357%, 12.48 cp이었고 재래식 죽초액의 경우는 1.012, 98.33%, 1.34%, 9.09 cp이었다. 색깔은 재래식 죽초액이 기계식 죽초액에 비하여 더 맑고 투명하게 나타났다. 그리고 pH와 총유기산, 용해타르 및 작열잔사의 함량은 기계식 죽초액이 각각 3.55, 2.83%, 2.803%, 0.671%이었고 재래식 죽초액이 각각 2.93, 3.47%, 0.051%, 0.004%이었다. 죽초액의 성분조성에 대한 조사에서 두 가지 경우의 죽초액이 모두 페놀성 성분은 주로 phenol, o-cresol, p(m)-cresol, guaiacol(2-methoxy phenol) 등이 검출되었고 유기산 성분은 주로 acetic acid, propionic acid, iso-butyric acid, nbutyric acid 등이 검출되었으며 알코올성분으로 methanol, furfuryl alcohol 및 maltol이 검출되었다. 페놀류와 알코올류의 함량은 기계식 죽초액의 편이 더 많고 유기산은 재래식 죽초액이 더 많이 함유되어 있었다.

Thermal Pyrolysis of Poly(vinyl alcohol) and Its Major Products

Poly(vinyl alcohol) (PVA) can be used to manufacture the immobilizing support of microorganisms in wastewater treatment systems. The withdrawn activated sludge contains lots of PVA. Before considering the thermal treatment of activated sludge containing PVA, one should investigate the behavior of PVA alone during the thermal treatment. The pyrolysis of PVA is thus examined with a thermal gravimetric analyzer (TGA). The kinetics of the thermal pyrolysis of PVA is conducted using nitrogen as the carrier gas in 378−1073 K and at various constant heating rates (HRs) of 5, 10, and 25 K/min. Major products are collected in 378−1073 K and at the constant HR of 5 K/min. The results indicate that the entire pyrolysis process of PVA under the experimental conditions of this investigation consists of two distinct pyrolysis stages. The corresponding activation energies E, reaction orders n, and frequency factors A of the reactions of two distinct pyrolysis stages are 148.35 and 129.4 kJ/mol for E, 1.04 and 1.48 for n, and 4.319 × 1011, and 5.169 × 106 1/s for A. The liquid products (condensates of gas at 298 K) consist of two layers (upper and lower layers). The distillation characteristics of the oil portions of both liquid products of upper and lower layers from the pyrolysis of PVA are between gasoline and diesel oil; meanwhile, the oil quality of the lower layer is better than that of the upper one. However, the upper level liquid product does not contain water, but the lower level one contains about 97.37−98.63 wt % water. The major gaseous products (noncondensable gases at 298 K) excluding N2 are HCs (hydrocarbons, 40.36 wt %), H2O (20.93 wt %), CO2 (19.77 wt %), and CO (18.94 wt %). The HCs mainly consist of C6 (14.3 wt %) and C1 (12.53 wt %). All this information is useful not only to the proper design of a pyrolysis system but also to the better utilization of liquid products and understanding of gaseous emission. The oil portions of liquid products can be obtained by the prefractional condensation or postdistillation.

Liquid products from oxidative thermal treatment of oil sludge with different oxygen concentrations of air

Oxidative thermal treatment of oil sludge with different oxygen concentrations of air by using a dynamic thermogravimetric (TG) reaction system is investigated. The experimental conditions employed are: gas flow rate of 50 cm3/min (value at 298 K) for 300 mg dry waste, a constant heating rate of 5.2 K/min, the oxygen concentrations in air of 1.09, 8.62 and 20.95 vol. % O2, and the temperature (T) range of 378-873 K. From the experimental results, the residual mass fractions (M) are about 78.95, 28.49, 8.77 and 4.13 wt. % at the oxidative T of 563, 713, 763 and 873 K for the case with 20.95 vol. % O2, respectively. The values of M with 8.62 and 1.09 vol. % O2 at T of 873 K are 4.87 and 9.44 wt. %, respectively. The distillation characteristics of the oil portion of liquid products (condensates of gas at 298 K) from the oxidative thermal treatment of oil sludge with 20.95 vol. % O2 at T of 378-873 K is close to those of commercial gasoline. Nevertheless, the liquid product contains a large amount of water. The distillation characteristics of the oil portions of liquid products with 8.62 and 1.09 vol. % O2 at T of 378-873 K are close to those of diesel and fuel oils, respectively. The oil quality with 8.62 vol. % O2 is better than that with 1.09 vol. % O2. However, the liquid product with 8.62 vol. % O2 still contains a large amount of water; nonetheless, that with 1.09 vol. % O2 is with negligible water. Compared with the oil product of nitrogen pyrolysis, the oil quality with 1.09 vol. % O2 is better. Certainly, low oxygen conditions (i.e. 1.09 vol. % O2) not only accelerate the thermal reaction of oil sludge, but also at the same time avoid or reduce the production of water. Further, from the analysis of benzene (B), ethylbenzene (E), toluene (T) and iso-xylene (X) concentrations of the oil portion of liquid products, the BETX concentrations of oil with 20.95 vol. % O2 are higher than those with 8.62 and 1.09 vol. % O2. The yields of liquid products with 20.95, 8.62 and 1.09 vol. % O2 at T of 378-873 K are 31.96, 34.42 and 37.3 wt. %, respectively. From the experimental results, the improvement effects of oxygen on the qualities of the oil portion of liquid products are obvious. The above technique not only formats good quality gasoline and diesel oils but also reduces large amount of oil sludge. If the oil exists with water, it may be obtained by further separation or collected by fractional condensation.

Major Products Obtained from the Pyrolysis of Oil Sludge

Oil sludge, if unused, is one of the major industrial wastes that needs to be treated for the refinery or petrochemical industry. It contains a large portion of combustible components with high heating values. Obviously, the conversion of oil sludge to various useful materials such as lower molecular weight organic compounds and carbonaceous residue via pyrolysis not only solves the disposal problem but also matches the appeal of resource utilization. In this study, the oil sludge from the oil storage tank of a typical petroleum refinery plant located in northern Taiwan is used as the raw material of pyrolysis. Its heating value of dry basis and low heating value of wet basis are about 10681 and 5870 kcal/kg, respectively. The pyrolysis of oil sludge is conducted by using nitrogen as carrier gas in the temperature range 378−873 K. The pyrolytic reaction is complex and significant in the range 450−800 K. The residues of pyrolysis of oil sludge exhibit very high viscous form below 623 K (pyrolysis temperature), while low viscous or solid form above 713 K. The major gaseous products (noncondensable gases at 298 K) excluding N2 are CO2 (50.88 wt %), HCs (hydrocarbons, 25.23 wt %), H2O (17.78 wt %), and CO (6.11 wt %). The HCs mainly consist of low molecular weight paraffins and olefins (C1−C2, 51.61 wt % of HCs). The temperature corresponding to the maximum production rate of HCs is 713 K. The distillation characteristics of liquid product (condensate of gas at 298 K) from the pyrolysis of oil sludge is close to diesel oil. However, it contains a significant amount of vacuum residue of about 9.57 wt %. The heating value of liquid product is about 10840 kcal/kg. All this information is useful not only to the proper design of a pyrolysis system but also to the better utilization of liquid oil product and understanding of gaseous emission.

DISTILLATION CHARACTERISTICS AND COMPOSITIONAL ANALYSIS OF ARABIAN LIGHT STRAIGHT RUN NAPHTHA

ABSTRACT Straight run naphtha is a basic constituent of refined petroteum products. It consists mainly of aliphatic hydrocarbons along with small amounts of naphthenic and aromatic hydrocarbons. It has a wide boiling range between 95°F and 410°F. Currently, its main utilization is as gasoline blend, however, naphtha is a potential feedstock for the production of various petrochemicals. Continuous catalytic reforming of naphtha can produce aromatic compounds in amounts up to 70% of the reformat. Nevertheless, the catalytic reforming process is usually associated with various limitations that may be related to the wide-ranging composition of naphtha. In this study straight run naphtha derived from Arabian Light crude oil was fractionated, and the hydrocarbon composition of its different distillation cuts was determined. The results indicate that, straight run naphtha can be split into two main fractions. A light fraction boiling between ambient temperature and 225°F, consists mainly of C7 (−) and a medium heavy fraction boiling between 225°F and 335°F, consists mainly of C7 (+). Detailed distillation characteristics, along with compositional analysis of SRN seems to be useful for diversifying its processing technologies, and upgrading currently applied processing practices to yield various high-value products and petrochemicals feed stocks.

Preparation and Properties of Biodiesel from Cynara cardunculus L. Oil

A study was made of the reaction of transesterification of Cynara cardunculus L. oil by means of methanol, using sodium hydroxide, potassium hydroxide, and sodium methoxide as catalysts. The objective of the work was to characterize the methyl esters for use as biodiesels in internal combustion motors. The operation variables used were methanol concentration (5−21 wt %), catalyst concentration (0.1−1 wt %), and temperature (25−60 °C). The evolution of the process was followed by gas chromatography, determining the concentration of the methyl esters at different reaction times. The biodiesel was characterized by determining its density, viscosity, high heating value, cetane index, cloud and pour points, Ramsbottom carbon residue, characteristics of distillation, and flash and combustion points according to ISO norms. The biodiesel with the best properties was obtained using 15% methanol, sodium methoxide as catalyst (1%), and 60 °C temperature. This biodiesel has very similar properties to those of diesel no. 2.