AN EVALUATION OF ASPHALT RIDGE (UTHA) TAR SAND BITUMEN AS A FEEDSTOCK FOR THE PRODUCTION OF ASPHALT AND TURBINE FUELS

The purpose of this study was two-fold. The first was to produce vacuum distillation residues and determine if their properties met ASTM asphalt specifications. The second was to determine if the distillates could serve as potential feedstocks for the production of aviation turbine fuels. The bitumen used for this study was the oil produced during an in situ steamflood project at the Northwest Asphalt Ridge (Utah) tar sand deposit.

Two distillation residues were produced, one at +316 °C (+600°C)and one at +399°C (+750°F). However, only the lower boiling residue met ASTM specifications, in this case, as an AC-30 asphalt. The original oil sample met specifications as an AC-5 asphalt. These residue samples exhibited some unique properties with respect to aging. It is suggested that the low aging indexes and high flow properties of the samples may be beneficial for pavements that require good low-temperature performance.

Two distillate samples were produced, one at IBP-316°C (IBP-600°F) and one at IBP-399°C (IBP-750°F). The chemical and physical properties of these samples were determined, and it was concluded that both samples appear to be potential feedstocks for the production of conventional and high-density aviation turbine fuels.     

An evaluation of the effect of storage and processing temperatures on the microbiological status of sous vide extended shelf-life products

The microbiological and organoleptic quality of selected sous vide products was monitored over a storage period of up to five weeks at 3°C and 8°C, respectively. Sous vide products stored at the recommended temperature of 3°C showed negligible microbial growth and were found to be organoleptically acceptable throughout the storage period. Total plate counts at the end of the fourth week of storage were in the range <10–7×10³ CFU/g for all 19 products under study. Listeria monocytogenes, Salmonella, Clostridium perfringens, Bacillus cereus and Enterobacteriaceae were not detected in any of the processed samples. At 8°C, under temperature abuse conditions, while some products had acceptable microbial levels of 10²–10⁴ CFU/g after three weeks, others such as chicken chasseur had counts above 10⁶ CFU/g by the second week of storage. Lactic acid bacteria and Pseudomonas species were dominant in the microbial flora of spoilt samples and B. cereus (>3×10⁴ CFU/g) was isolated from spoilt chicken chasseur samples in the fourth week of storage at 8°C. Critical factors affecting sous vide product safety are discussed.     

SUPERCRITICAL EXTRACTION AND DESULPHURIZATION OF BEYPAZARI LIGNITE BY ETHYL ALCOHOL/NaOH TREATMENT 2. KINETICS

The reaction of Beypazari lignite with ethyl alcohol/NaOH was carried out using a microreactor of 15 ml capacity. The microreactors were developed to examine the reaction kinetics of coal extraction and desulphurization under supercritical conditions. The experimental temperature in the microreactor was adjusted to 245°C, 275°C and 295°C. The duration of the experiments was changed between 0 to 90 minutes.

The solubilization of Beypazari lignite increased sharply from 15% to 50% within 30 minutes after the temperature reached to 245°C and gradually decreased from 50% to 48% in 90 minutes. The total sulphur (pyritic and organic) content of the acid washed lignite decreased from 3.78% to 2.50% in the first 10 minutes and insignificant changes were observed at longer durations. The percentage of the pyritic sulphur remained constant at about 0.25% throughout the experiments. As the temperature was increased from 245°C to 295°C the time for steady state decreased from 32 minutes to 21 minutes. Solubilities obtained in the steady state for experiments at 245°C, 275°C and 295°C were 50%, 52% and 60%, respectively. The order of the reaction changed between 0.85-0.89 for experiments run at 245°C, 275°C and 295°C. The activation energy of the solubilization reaction for the interaction of Beypazari lignite with ethyl alcohol/NaOH system was calculated as 28.8 kcal/mole. As the reaction time is increased from 18 minutes up to 90 minutes the infrared spectra became more complex and both the number of the peaks due to sulphur groups and the intensity of these peaks increased. When the temperature was increased from 245°C to 295°C the average molecular weight of the liquid products increased from 465 to 550.     

Shelf-life of chilled cut orange determined by sensory quality

The shelf-life of chilled cut orange was evaluated in terms of physical and chemical quality characteristics, microbial contamination and sensorial acceptability. After minimal processing (peeling and cutting), fresh orange was stored in air at 4 °C. Evaluations were performed at different times of storage. The respiration rate of the fresh-cut orange was also evaluated. No significant increase was noticed in relation to the whole fruit which means that this was not the factor responsible for an accelerated deterioration of the product. During the first eight days of storage the major quality parameters remain almost unchangeable, except for titratable acidity which decreased around 36% and ascorbic acid content which decreased around 22%. With respect to microbial contamination low temperature determined a considerable shelf-life (15 days). Sensory quality was the parameter which determined the shelf-life of cut orange to five days at 4 °C due to flavour changes.     

Thermodynamic Aspects of Aromatic Hydrogenation

Aromatic hydrogenation is one of the important classes of hydrotreating reactions and its thermodynamics play a significant role in achieving the product specifications. This article comprehensively reviews the available experimental thermodynamic data as well as the methods to estimate the data for aromatic hydrogenation. The data indicate that aromatic hydrogenation reactions are thermodynamically more favorable at about 200°C-250°C and moderate pressures (3-5 MPa). Industrially, however, these reactions are carried out at 300°C-375°C to have reasonable kinetics. Hence there is a need for highly active catalysts, which can facilitate significant kinetics of hydrotreating reactions at around 200°C-250°C.     

Survival and growth of Listeria monocytogenes on sausage formulated with inoculated and stored rework product

To assess the effect of including contaminated rework on survival and growth of Listeria monocytogenes, two sausage formulations (one American, Bologna sausage; and one Bulgarian, Stranja sausage) were inoculated with the pathogen and stored for 4 days at 10 °C plus 15 h at 30 °C. After storage, both rework types were included (at 20% and 40%) in corresponding fresh sausage emulsions and heated to 68, 70 and 71.7 °C; fresh Bologna and Stranja emulsions served as controls and were inoculated with 24 h broth cultures of the same 10-strain mixture of L. monocytogenes and thermally treated to the same temperatures. The results showed that heating to 68 and 70 °C inactivated 3–4 log CFU/g of the initial concentration of L. monocytogenes cells (>7 log CFU/g), while heat treatment to 71.7 °C in the center of experimental samples reduced counts by 6 log CFU/g. Survival of L. monocytogenes in samples heated to 68 and 70 °C was higher in controls. Control samples of Stranja emulsion heated to 71.7 °C allowed higher growth (P < 0.05) during storage (5 days at 10 °C) as compared to other control and experimental rework samples. The Stranja emulsion had a higher fat content (20.2%) compared to the Bologna emulsion (11%). This study provides evidence about the possible danger when potentially contaminated rework is stored and then introduced into fresh product formulations.     

Characterization of Thermally Degraded Asphaltene Fractions Using Gel Permeation Chromatography

Petroleum asphaltene goes through three stages of mass reduction under thermogravimetric analysis from 25°C to 1,000°C at a heating rate of 1°C/min. The products from thermal degradation of asphaltene at three different temperature intervals are collected. Two residual fractions left in the sample cup are also obtained at two specific temperatures. The collected fractions and the residual fractions are characterized using gel permeation chromatography. The fraction collected between 25°C and 350°C demonstrates similar molecular weight distribution to that collected between 350°C and 450°C, with both fractions showing a typical molecular weight distribution for polymeric material. The fraction collected between 450°C and 650°C illustrates three different molecular weight distributions. The chromatogram of the residual fraction obtained at 350°C resembles that of the undegraded asphaltene. The residual fraction obtained at 450°C also demonstrates three different molecular weight distributions. The experimental data indicate that the mass reduction of asphaltene heated from 25°C to 350°C is mainly due to the evaporation of low boiling point and/or low molecular weight substances in asphaltene. Thermal decomposition and coke production occur significantly in the 350°C-450°C temperature interval. Thermal degradation continues to finish until 650°C.     

CHARACTERIZATION OF ARAB BERRI (EXTRA LIGHT) CRUDE FRACTIONŞ WITH EMPHASIS ON KINEMATIC VISCÓSITY-TEMPERATURE BEHAVIOR

The characterization data has been obtained for Arab Berri extra light crude oil (API° 46.9), which is one of the four crude oils being commercially produced by Saudi Arabia. Further, six true boiling point fractions (IBP-95°C, 95-205°C, 205-260°C, 260-34S°C, 345-455°C and 455°C+) of this crude were characterized in terms of API gravity, total sulfur, H₂S, merceptans, molecular weight, elemental analysis for total carbon, hydrogen and nitrogen, analysis of various metals and paraffin, aromatic and naphthalene contents of lighter fractions. The kinematic viscosity-temperature data have been obtained for 95°C+ TBP fractions for wide range of temperatures.     

Reducing nitrite content in hot dogs by hurdle technology

The objective of the present study was to reduce nitrite content in hot dogs using hurdle technology without sacrificing product safety and quality. In the present study, the water activity of the hot dog was adjusted to 0.95 by the addition of humectants. Although the pH at the hot dog was adjusted with Glocono-delta-lacton to 5.4, the product had (p > 0.05) the least acceptance on account of the organoleptic changes (sour taste). Moreover, the temperature of 80 ± 1 °C for an hour with the aim of achieving an internal temperature of 75 °C was applied. Subsequently, the temperature of the hot dog samples reduced to around 5–6 °C within 40–45 min, and afterwards the sausages were kept at chilled temperature (>3 °C but 10 °C) throughout their shelf life. There was a decrease in total aerobic counts in hurdle treated hot dogs (with 50 ppm nitrite), compared to the control (with 120 ppm nitrite), whereas Clostridium perfringens counts and Clostridium botulinum detection were the same (p < 0.05) in both hurdle treated and control samples. The obtained results of present study clearly showed that both hurdle treated sample and control had the same (p < 0.05) overall acceptability and sensory attributes.     

Synthesis of Tert-amyl Methyl Ether with Methanol and C5 Hydrocarbons

The reaction system and mechanism of etherification of C5 cut with methanol were analyzed theoretically. Experiments were carried out in a tubular reactor at temperatures of 50°C-80°C in the presence of a strong cation-exchange resin, QRE. In the reaction system, two types of reactions took place: etherification and isomerization. At lower temperature, the reaction rates were controlled by kinetic factors, but at temperature above 60°C, both reactions were affected by thermodynamic equilibrium. The appropriate operating conditions were: T at 60°C-65°C, molar ratio of methanol and isoamylenes 1.0-1.2, and liquid hourly space velocity (LHSV) 1.0-1.5.     

Survival of Salmonella spp. on surface-inoculated forced-air cooled and hydrocooled intact strawberries,and in strawberry puree

Fresh-market strawberries are cooled to 1–3 °C before commercial storage and distribution; typically by forced-air cooling. Hydrocooling ensures a faster and more uniform cooling of strawberries, although its effect on reducing microbial contamination on the fruit has not been evaluated. Salmonella has been reported to survive on damaged strawberries, but is unable to multiply, potentially due to the low pH or other intrinsic factors associated with strawberries. This study evaluated Salmonella survival a) on the surface of intact hydrocooled or forced-air cooled strawberries; b) as affected by agitation and density of packing during hydrocooling and c) as affected by pH, temperature and food matrix (strawberry or tomato puree). Intact strawberries inoculated with Salmonella were subjected to forced-air cooling or hydrocooling in water containing 100 or 200 ppm HOCl. Salmonella population was enumerated 0, 7 and 8 days post-treatment. Strawberry and tomato puree (pH 3.7 and 4.6) spiked with Salmonella and incubated at 4, 10 or 25 °C, were evaluated at 0, 1 and 3 days post-inoculation (n = 9). Compared to forced-air cooling, hydrocooling significantly reduced Salmonella survival on inoculated intact strawberries, with levels below the enumerable limit (1.5 log CFU/berry) by day 8. Hydrocooling reduced the initial Salmonella levels by 1.9 log CFU/berry, while the addition of 100 or 200 ppm HOCl reduced levels by 3.5 and 4.4 log CFU/berry, respectively. Initial Salmonella populations (day 0) were significantly lower when the berries were agitated or loosely packed during hydrocooling. Salmonella survival was significantly higher at a higher pH (4.7) compared to lower intrinsic pH (3.6) of strawberry puree. Higher temperature (25 °C) was conducive for Salmonella survival on strawberry puree compared to lower temperatures (4 and 10 °C). The data shows that a lower pH of 3.6 or refrigeration below 10 °C are effective in controlling the survival of Salmonella on damaged strawberries.     

Characteristic Properties of a Locally Produced Paraffinic Oil and Its Suitability as a Heat-Transfer Fluid

The thermo-physical properties of a paraffinic mineral oil produced in a local refinery were experimentally determined over a wide temperature range of 30-360°C to determine its suitability for use as a heat-transfer fluid. The effect of temperature on the physical characteristics of the oil and two synthetic organic heat transfer fluids was evaluated at high temperatures (180-360°C). Comparison of the main properties of the mineral oil with other heating fluids revealed its compatibility with synthetic organic fluids, some other paraffinic and mineral oils employed as heat-transfer fluids. The study further confirmed that the investigated mineral oil which was produced locally can be used to replace the imported synthetic oils in heat transfer systems operating at a maximum application temperature of 310°C, as indicated by the thermal stability test.     

DEEP DESULPHURISATION OF A DIESEL BLEND IN A PILOT PLANT TRICKLE BED REACTOR

A pilot plant investigation was conducted to study the influence of hydrotreating conditions on conversion and characteristics of diesel blend and to determine the severity of operating conditions required to meet the proposed product specifications for diesel fuel in India. A typical diesel blend derived from various refinery streams with sulphur content of 2·06 wt% was hydrodesulphurised over a commercial NiO-MoO₃/Al₂O₃ catalyst in a pilot plant trickle bed reactor. The experiments were conducted at 300-370°C, 30-50 kg/cm², 2·0 3·0 hr^-1 liquid hourly space velocity and constant H₂/oil ratio of 185 m³/m³. The data showed that the diesel blend could be hydrotreated to meet revised product specifications of 0·25 wt% sulphur, 46 cetane number by increasing the severity of operation. The cetane number and aromatic saturation were limited by thermodynamic equilibrium at temperatures above 360°C. The influence of temperature was found to be more pronounced than that of pressure in the range of operating conditions studied.     

LIQUEFACTION OF BEYPAZARI LIGNITE USING NiCl2-KCl-LiCl CATALYSTS. 1. DIFFERENCE IN SOLID AND MOLTEN SALT CATALYSIS

Liquefaction of Beypazan lignite in tetralin using NiCl₂-KCl-LiCl (14:36:50 molar percentages) as catalyst was investigated. Effects of the catalyst/lignite ratio and temperature were determined in experiments done at 275°C, 300°C and 360°C. Liquid products were separated into oils, asphaltenes and asphaltols by a solvent extraction method. Yield of liquefaction increased with temperature in all experiments, the highest yield was observed in experiments performed at the eutectic temperature of the catalyst mixture. The highest yields of oils were 20% and 30% with a catalyst/coal ratio of 0.5 at 275°C and 300°C, respectively. The activity of the catalyst increased in experiments in which the catalyst was molten. The yield of asphaltenes were not affected with increases in the catalyst/coal ratio in the experiments done at 275°C or 300°C in which the catalyst mixtures were in solid state. Asphaltene yields decreased from 25% to less than 5% with increasing values of catalyst/coal ratio and the asphaltol yields remained constant at 10% between catalyst/coal ratios of 0.25 and 1.00 and suddenly increased to 30% and 40% for catalyst/coal ratios of 1.50 and 2.00, respectively, at 360°C. The molecular weights of the oils decreased from 340 to a minimum value of 245 as the catalyst/coal ratio was increased from 0 to 1.00 in experiments done at 360°C where the catalyst was molten. As the catalyst/coal ratio was further increased from 1.00 to 2.00 the molecular weight increased to 310.It seemed that the N1Cl₂-KCl-LiCl catalyst mixture in all catalyst/coal ratios was more efficient in molten phase than it was used as a solid mixture.     

STEAM GASIFICATION OF BALMER COAL IN THE PRESENCE OF LIGNITE ASH

Steam gasification of blends prepared from Balraer coal and the ash from combustion of Onakawana lignite was performed in a fixed bed reactor. The blends were prepared by co-slurrying followed by drying. In the presence of 20 wt % ash the gasification rate doubled at 830° and 930°C. Direct blending of coal and lignite resulted In an overall increase in carbon conversion at 830°C but had no effect at 930°C.     

Effect of nisin on the storage of sous vide processed Korean seasoned beef

Seasoned beef called Jangzorim in Korea is produced by boiling in soy sauce, and is a popular food in Korea. The aim of this study is to evaluate the microbial safety and physical qualities of sous vide processed seasoned beef, and the effect of nisin during storage. Sous vide processed packages with or without nisin (100 IU or 500 IU) were stored at 4 °C or 25 °C for 60 days, and samples measured for quality at regular intervals throughout this storage period. In the case of 25 °C storage, the number of mesophilic microorganisms in seasoned beef packages without nisin increased markedly, but with nisin there was no observed increase. Psychrotrophic microorganisms, anaerobic microorganisms, and B. cereus cells showed similar trends, although C. perfringens was not detected in all samples. At 25 °C storage, changes in the cutting force of packages containing nisin showed no significant change, packages without nisin decreased markedly. The colour of packages without nisin showed a drastic decrease in lightness (‘L’) while no changes were observed in packages with nisin.     

Thermal Hydrocracking Kinetics of Chinese Gudao Vacuum Residue

The thermal hydrocracking kinetics of Chinese Gudao vacuum residue was studied in a batch autoclave reactor. The temperature ranged in 390-435°C and the initial hydrogen pressure was 7.0 MPa at 20°C. Ammonium phosphomolybdate (APM) in its dispersed phase was the catalyst. The reaction products, gas, naphtha, atmospheric gas oil (AGO), vacuum gas oil (VGO) and coke, were separated during and after experiments, and their yields vs. reaction time were obtained, for four reaction temperatures: 390, 405, 420, and 435°C. The activation energy was calculated from a traditional kinetic model to be 218.6 kJ/mol. A new kinetic model was proposed in this work that allows for the calculation of activation energy with a minimum number of three tests, each at a different temperature. This is comparable to the traditional model which requires a minimum of 12 tests; a minimum of four tests for one temperature and a minimum of three temperatures. The activation energy calculated from the new model with four tests is 229.6 kJ/mol, only 5% greater than that obtained from the traditional model. The reaction rate constants obtained from this model are also consistent with those from the traditional model.     

COMPARISON OF OXIDATION OF SHRP ASPHALTS BY TWO DIFFERENT METHODS

An objective of the Strategic Highway Research Program is the development of a test procedure that accurately predicts changes in asphalt pavement properties with aging. Many of the methods now in use do not give reliable results. It is desirable to develop a method that takes into account maximum temperatures to which asphalts are subjected in mix plants (about l60°C or 320°F) and during service (60° C or 140°F), but is not impractically long. Therefore, test conditions must involve increased temperature, pressure, or the addition of a chemical accelerant but yield artificially aged materials that have certain properties similar to those of aged pavement binders.|In this study, rheological and chemical properties of asphalts subjected to thin-film oven followed by pressure vessel oxidation under two sets of conditions were compared with properties of asphalts aged in the thin-film accelerated-aging test at two temperatures. Oxidations of asphalts for 144 hours (6 days) at 60°C (I40°F) and 2.07 × 10⁶ Pa pressure following a standard thin-film oven treatment yielded products having characteristic aging indices and enhanced sulfoxide and carbonyl absorbances in their infrared spectra. Oxidation of asphalts under thin-film accelerated-aging lest conditions at 85°C (185°F) for 144 hours provides aged asphalts with rheological properties similar to those obtained from the 60°C (140°F) pressure oxidations. When the pressure oxidation was run at 80°C (176°F) for 144 hours. materials were obtained that were more extensively aged. The aging indices of these materials were somewhat similar to asphalts oxidized for 72 hours at 113°C (235.4°F) under thin-film accelerated-aging test conditions. The aging lendencies of the eight asphalts tested were ranked by the two latter methods in approxmiately the same order.|The thin-film accelerated-aging test procedures are readily performed in a standard oven. but utilize smaller samples (resulting in less material for subsequent analysis) than the pressure oxidations. It is not certain that the mechanism or kinetics of the asphalt oxidations in the higher temperature oven procedures are identical to the mechanisms of oxidation of asphalts in pressure aging. The procedures used in this study, although not themselves definitive test conditions for asphalt-binder aging. should aid in the selection of conditions for an improved aging lest.     

Effects of some Chinese medicinal plant extracts on five different fungi

Chinese medicinal plant extracts were screened against some fungal strains, such as Aspergillus niger, Botrytis cinerea, Fusarium moniliforme, Glomerella cingulata, and Phyllosticta caricae. Plants were extracted with hot water, 80% methanol or acetone. Aliquots of the extracts at variable concentrations were then incubated with different fungal strains, and the minimum inhibitory concentrations (MICs) of each plant extract determined. In this study, the methanol extracts of Cinnamomum cassia had MIC values of 13.3 mg ml⁻¹, when tested against F. moniliforme and P. caricae. The acetone extracts of C. cassia had MIC values of 8.3 mg ml⁻¹ and 10 mg ml⁻¹ respectively, when tested against B. cinerea and G. cingulata. The hot water extracts of C. cassia inhibited significantly the growth of A. niger, B. cinerea, F. moniliforme, and P. caricae with MIC values at 10, 11.7, 5, and 6.7 mg ml⁻¹ respectively. The acetone extracts of Curcuma longa inhibited effectively P. caricae with the MIC value at 6.7 mg ml⁻¹. To determine the stability, various plant extracts were stored at 4 and 25 °C over a period of one month and their effects on fungal growth examined. Results show that the acetone extracts of Cu. longa and Coptidis rhizoma maintained their activity against fungal strains when stored at 4 °C, but not at 25 °C. The methanol extracts of C. cassia lost a great portion of inhibitory activities but not all, after stored at 4 °C and 25 °C for one month. The effect of various combinations of these extracts on antimicrobial activity has also been examined. The combinations of herb extracts showed higher inhibitory effect towards tested fungi than that of individual extract. Results from these findings suggest that these herbal extracts may be used as natural antifungal agents to inhibit growth of foodborne pathogen.     

AROMATIC HYDROCARBONS OBTAINED BY THERMAL CONVERSION OF GREEN RIVER OIL SHALE KEROGEN USING CO AND H2O AT ELEVATED PRESSURE

Aromatic hydrocarbons produced from the reaction of Green River oil shale with carbon monoxide and water at elevated pressure and at temperatures from 300 to 450°C were investigated. The isolation of these aromatic hydrocarbons involved ion exchange, complexation, silica gel, and alumina chromatographic techniques. Compound types present in these aromatic hydrocarbons were studied by high resolution mass spectrometry and combined gas chromatography-mass spectrometry. Compound types were mostly phenylcyclohexylal- kanes, dinaphthenobenzenes, trinaphthenobenzenes, naphthenonaphthalenes, and carotenoid types at 300°C; but at 450°C compound types were mostly alkyl-benzenes, alkylbiphenyls, and alkylnaphthalenes. The composition of aromatic hydrocarbons from the benzene-extracted bitumen of Green River oil shale was found to be similar to that in the 300°C product from the CO-H₂O reaction.