Formulation of fumed silica grease from waste transformer oil as base oil

This study aimed to formulate fumed silica (FS) grease using waste transformer oil (WTO) and to investigate the grease properties. Various unexplored application of the reused WTO due to its reusable characteristic. WTO and fresh transformer oil (ITO) were used as grease base fluid and the properties of oil and grease were evaluated using ASTM International standards and SKF’s Grease Test Kit. The oil and grease chemical compound were determined using Fourier Transform-Infrared Spectroscopy at wavenumber of 500–4000?cm^?1. It was found that WTO have high viscosity index of 96 and low moisture content of 0.05% after pre-treatment than ITO. FS greases with and without MoS₂ were classified as NLGI 2 greases when FS content was 8%. Grease formulated with MoS₂ shows better performances in term of corrosiveness, oil bleed within ?15% to +15%, oil separation less than 4%, and dropping point of >300?°C. FTIR results shows no significant different between ITO and WTO, and between all formulated greases. Based on the findings, it was concluded that WTO can be utilized as an alternative base oil in grease formulation due to the good properties exhibited by the formulated WTO-based FS grease blended with MoS₂.     

Synthesis of temperature-resistant and salt- tolerant surfactant SDB-7 and its performance evaluation for Tahe Oilfield flooding （China）

In order to improve the enhanced oil recovery of high-temperature and high-salt oilfields, a novel temperature-resistant and salt-tolerant surfactant （denoted as SDB-7） was synthesized and evaluated for the Tahe Oilfield （Xinjiang, China）, which is representative of high-temperature and high-salt oilfields. It has a central reservoir temperature of 140 ℃ and salinity of 22.6× 10^4 mg/L. The temperature-resistant and salt-tolerant performance, interfacial activity, oil displacement efficiency, aging properties, and adsorption properties of the synthesized surfactant were evaluated for Tahe Oilfield flooding. The results showed that the SDB-7 was temperature-resistant and salt-tolerant capacity of 140 ℃ and 22.6×10^4 rag/ L, respectively, oil displacement efficiency under static condition of 84%, and adsorption loss of 0.4 mg/ g （less than 1 mg/g-oil sand）. In the heat aging experiment （under the temperature of 140 ℃ for 60 days）, the oil-water interracial tension and oil displacement efficiency of SDB-7 were almost unchanged. The oil displacement experiments showed that, under the temperature of 140 ℃ and the salinity of 22.6× 10^4 mg/L, the surfactant SDB-7 can enhance oil recovery by 14.5% after water flooding,suggesting that SDB-7 has a promising application in high temperature and high salinity （HT/HS） reservoir.     

Synthesis,interface activity and oil flooding experiment with an authentic sandstone microscopic model of cationic gemini surfactant

In this work, a series of cationic gemini surfactants with different hydrophobic tails were prepared and characterized by element analysis, IR spectra, and ¹H NMR spectra. The influencing factors of physic-chemical properties of these surfactants were carefully studied. The critical micelle concentration (CMC) of all the surfactants ranged from 3.87 × 10^?4 mol L^?1 to 8.97 × 10^?4 mol L^?1 and the values (γ_cmc) also ranged from 28.62 mN m^?1 to 34.07 mN m^?1 at CMC level by surface tension experiments. The consequences of the oil/water interface tension experiments indicated that all these prepared surfactants could lower oil/water interface tension to ultra-low with the combination of Na₂CO₃. C₁₂-2-C₁₂, and C₁₄-2-C₁₄ were chosen as the representative to evaluate the displacement efficiency in the oil flooding experiments using authentic sandstone microscopic model. The results showed that these surfactants could effectively improve the displacement efficiency by 10–20%.     

Biodegradation of Used Engine Oil by a Methylotrophic Bacterium,Methylobacterium Mesophilicum Isolated from Tropical Hydrocarbon-contaminated Soil

A Gram-negative facultatively methylotrophic bacterium putatively identified as Methylobacterium mesophilicum strain RD1 displayed extensive degradative ability on used engine oil (SAE 40W) in liquid cultures. The rate of degradation of used engine oil (1274.85 mg L^?1) by the isolate, for the first 12 days and the last 9 days were 65 and 40 mg L^?1 d^?1, respectively. Gas chromatographic (GC) analyses of residual used engine oil revealed that 61.2% and 89.5% of the initial concentration of the used engine oil were degraded within 12 and 21 days. GC fingerprints of the used engine oil after 12 days of incubation showed total disappearance of C₁₅, C₂₃, C₂₄, C₂₅, and C₂₆ hydrocarbon fractions as well as drastic reductions of C₁₃, C₁₄, C₁₆, and PAHs fractions such as C₁₉-Anthracene and C₂₂-Pyrene. At the end of 21 days’ incubation, total disappearance of C₁₇-pristane, C₂₂-pyrene, one of the C₁₉-anthracene, and significant reduction of C₁₈-phytane (96.8%) fractions were observed. In addition, less than 10% of Day 0 values of medium fraction ranges C₁₃, C₁₄, and C₁₆ were discernible after 21 days. This study has established the potential of Methylobacterium mesophilicum strain RD1 in degradation of aliphatic, aromatic, and branched alkane components of used engine oils.     

Bacteria as indicators for finding oil and gas reservoirs: A case study of the Bikaner-Nagaur Basin, Rajasthan, India

Geo-microbial prospecting for hydrocarbons is an exploration method based on the seepage of light gaseous hydrocarbons from oil/gas reservoirs to the surface and their utilization by hydrocarbon oxidizing bacteria.These bacteria utilize hydrocarbon gases as their sole source of food and are found to be enriched in the near surface soils/sediments above the oil and gas reservoirs.The detection of anomalous populations of n-pentane and n-hexane oxidizing bacteria in the surface soils can help to evaluate the prospects for hydrocarbon exploration.A geo-microbial survey has been carried out in the Bikaner Nagaur basin to investigate the prospects for hydrocarbon exploration.In the present study,bacterial counts for n-pentane utilizing bacteria range between 2.0×10 2 and 1.26×10 6 cfu/gm and n-hexane utilizing bacteria range between 2.0×10 2 and 1.21×10 6 cfu/gm.The bacterial concentration distribution maps show four distinct anomalies in the study area.The possibility of discovering oil or gas reservoirs using the microbiological method is emphasized by the fact that the hydrocarbon-oxidizing bacteria range between 10 3 and 10 6 cfu/gm in soil/sediment receiving hydrocarbon micro-seepages.In the present study area of the Bikaner Nagaur basin,n-pentane and n-hexane utilizing bacteria are found between 10 5 and 10 6 cfu/gm of soil sample,which is significant and thereby substantiates the seepage of lighter hydrocarbon accumulations from oil and gas reservoirs.Geo-microbial prospecting studies suggest that hydrocarbon micro-seepage of subsurface origin is present in the study area and indicate that the area has positive prospects for petroleum exploration.     

Optimization,kinetics, physicochemical and ecotoxicity studies of Fenton oxidative remediation of hydrocarbons contaminated groundwater

Fenton oxidation remediation of hydrocarbons contaminated groundwater was investigated for efficiency and effectiveness. 10% pollution was simulated in the laboratory by contaminating groundwater samples with diesel and domestic purpose kerosene (DPK) in two different experimental set ups. Optimum conditions of concentrations of the treatment solutions and pH were established: 300 mg/L (FeSO₄), 150,000 mg/L (H₂O₂) and pH = 3 for the kerosene contaminant; 100 mg/L (FeSO₄), 300,000 mg/L (H₂O₂) and pH = 3 for the diesel contaminant. The results from kinetics study show that the remediation process is pseudo-first order reaction with a rate constant of 8.07 × 10⁴ mgL^?1hr^?1 and 3.13 × 10⁴ mgL^?1hr^?1 for the diesel and kerosene contaminants in that order with 95.32% and 79.25% reduction in chemical oxygen demand (COD) for diesel and kerosene contaminated samples at the end of the remediation process respectively indicated that remediation have occurred significantly. Percent reduction in Total Petroleum Hydrocarbon (TPH) as kerosene was 89.84% and that of the diesel contaminant as 91.87% after 6 hours of remediation. The general pollution index (GPI) for the hydrocarbons contaminated samples was in the range of 6.70–7.52 against the background value of 4.39 for the control groundwater sample. After treatment the GPI had dropped to 4.13–4.43 which depicts remarkable remediation although the samples remained impaired. Therefore there is the need of post-treatments to make the groundwater fit for domestic and agricultural uses. The application of the Fenton oxidative process is found to be very efficient, effective and rapid in reducing total petroleum hydrocarbon as kerosene and diesel as target contaminants.     

Antimicrobial activity of clove (Syzgium aromaticum) oil in inhibiting Listeria monocytogenes on chicken frankfurters

The ability of Listeria monocytogenes to survive and grow at refrigeration temperature in some ready to eat (RTE) poultry products is a public health concern. The inhibitory effect of clove oil (1% and 2%, v/w) applied to the surface of RTE chicken frankfurters was determined on seven strains of L. monocytogenes inoculated at low (10²–10³ cfu/g) or high cell numbers (10⁴–10⁶ cfu/g), and stored at 5 °C for 2 weeks or at 15 °C for 1 week. All strains of L. monocytogenes survived and grew on control frankfurters at 5 °C and 15 °C but growth was inhibited under both storage conditions in the presence of either 1% or 2% clove oil. Depending on the sensory considerations, the addition of clove oil to frankfurters may be an effective strategy to control L. monocytogenes in chicken frankfurters.     

Synthesis and Surface Active Properties of Novel Nonionic Aryl Oleic Diethanolamide Surfactants

Abstract

A series of novel aryl oleic diethanolamide (AOD) surfactants with different hydrophobic groups were synthesized. An aromatic ring introduced to a long alkyl chain had a significant effect on reducing water surface tension. The critical micelle concentration (CMC) and the surface tension (γ _cmc ) at the CMC were investigated. The CMC was 4.56 × 10^?8 mol/L to 5.83 × 10^?6 mol/L for AOD1:1 (molar ratio of aryl oleic acid: diethanolamide = 1:1) and corresponding γ _cmc was 36.4 mN/m to 39.3 mN/m. The CMC of AOD1:2 (molar ratio of aryl oleic acid: diethanolamide = 1:2) were in 1.21 × 10^?7–9.98 × 10^?6 mol/L and γ _cmc were in 31.6–34.4 mN/m.     

Electrical and dielectric properties of self-assembled polyaniline on barium sulphate surface

Solid polymer electrolytes have been broadly studied due to their wide applications in various electrochemical devices. In the present work, the electrical properties of polyaniline and its composites with BaSO₄ have been studied. The polymerization of aniline monomer via the ordinary chemical polymerization process showed an amorphous structure. Whereas, in the presence of BaSO₄ as a seed, the aniline is polymerized in an orthorhombic crystalline structure on the BaSO₄-surface. Two composite samples of PANI and BaSO₄ with different amounts of BaSO₄ (1.5 and 2.5 wt%) were prepared and analyzed using XRD, FT-IR, SEM, and XPS techniques. The ac- electrical studies on the composites showed an enhancement in the electrical conductivity of PANI due to the addition of BaSO₄. Ac- conductivity at frequency 500 kHz, and 100 °C, showed values of 1.9 × 10⁻³, 5.4 × 10⁻⁴, 1.6 × 10⁻¹, and 1.9 × 10⁻¹ S/cm for PANI, BaSO₄, BaSO₄/PANI 1.5 wt%, and BaSO₄/PANI 2.5 wt%, respectively.     

Kinetics and Selectivity of Asphaltene Thermal Cracking,Thermal Hydrocracking,and Catalytic Hydrocracking

Abstract

A pentane-insoluble asphaltene was processed by thermal cracking, thermal hydrocracking, and catalytic hydrocracking in a microbatch reactor at 430°C. The experimental data of asphaltene conversion fit second-order kinetics adequately to give the apparent rate constants of 1.704 × 10^?2, 2.435 × 10^?2, and 9.360 × 10^?2 wt frac^?1 min^?1 for the above three cracking processes, respectively. A three-lump kinetic model is proposed and solved to obtain rate constants of parallel reactions of asphaltenes to produce liquid oil (k₁) and gas + coke (k₃) and a consecutive reaction from liquid to gas + coke (k₂). The value of k₁ is 1.697 × 10^?2, 2.430 × 10^?2, and 9.355 × 10^?2 wt frac^?1 min^?1; k₂ is 3.605 × 10^?2, 2.426 × 10^?2, and 6.347 × 10^?3 min^?1; and k₃ is 6.934 × 10^?5, 5.416 × 10^?5, and 4.803 × 10^?5 wt frac^?1 min^?1 for asphaltenes thermal cracking, thermal hydrocracking, and catalytic hydrocracking, respectively. Analysis of selectivity shows that the catalytic hydrocracking process provides the highest liquid production, and the coking process provides the highest coke formation, as expected. An induction period of coke formation was found to increase from thermal cracking to thermal hydrocracking to catalytic hydrocracking process.     

Evaluation of Surfactants for the Cost Effective Enhanced Oil Recovery of Assam Crude Oil Fields

Based on a hierarchial methodology, the article presents the comparative efficacy of Vim commercial detergent for the purpose of surfactant enhanced oil recovery of Assam crude oil in Indian reservoirs. Suitable technical and economic indices were defined to explore the economic competence with other surfactants such as sodium dodecyl benzene sulfonate and sodium dodecyl sulfonate. It was evaluated that the detergent formulation provided the following performance characteristics: I_C = 13.43 mN/m.g/L surfactant solution, surfactant sustainability index = 3.88 × 10^?3 mN/m.$/L surfactant solution, cost ratio = 0.32 ? 0.52 $ surfactant/$ crude oil recovered and 14.7–15.1% tertiary recovery with respect to original oil in place. Further ultralow interfacial tension formulations were also achievable with the commercial detergent.     

Thermal Safety Study on TEGDN/NG/NC Gun Propellant

The self-accelerating decomposition temperature (T_SADT), critical temperature of thermal explosion (T_b), adiabatic time to explosion (t_TIad), 50% drop height of impact sensitivity (H₅₀), critical temperature of hot spot initiation caused by impact (T_cr,hotspot), safety degree (S_d), critical thermal explosion ambient temperature (T_acr), and thermal explosion probability (P_TE) of the gun propellant composed of triethyleneglycol dinitrate (TEGDN), nitroglycerin (NG), and nitrocellulose (NC) were studied. The results of thermal safety evaluation on the gun propellant were obtained: (1) T₀₀ = 433.4 K, T_SADT = T_e0 = 441.1 K, T_b = T_bp0 = 468.4 K; (2) when E_k = 205.3 × 10³ J mol ^?1 and A_k = 10^20.62 s ^?1, t_TIad = 48.3 s, H₅₀ = 17.93 cm, T_{cr, hotspot} = 634.9 K; for a sphere sample, T_S(T)max  = 369.0K, T_acr = 364.2 K, S_d = 65.03%, P_TE = 34.96%.     

Optimization of chemical agents for removing dispersed oil from produced water in Z oilfield

Produced water generated in oil and gas industries contains various organic and inorganic components. Discharging produced water is becoming a problem that needs considerable attention because it can pollute surface and underground water and soil. Major research efforts focus on the treatment methods that were feasible in the view of efficiency and economy. The dispersed oil particles (dop) in the produced water can pollute the underground water and soil and cause blockage in the reinjection process of produced water. In order to obtain a feasible treatment method for removing the dispersed oil from produced water in Z Oilfield, the crude oil from Z Oilfield was analyzed by nuclear magnetic resonance (NMR) spectroscopy. The result showed that the oil was mainly composed of alkanes and aromatic hydrocarbons. Materials with polar group did not exist in the crude oil. The influence of four different agents RDP₁, RDP₂, RDP₃, and RDP₄ on the removal of dop was studied at 45°C in this paper. The result showed that RDP₃ was the most optimal agent for Z Oilfield. The concentration of RDP₃ was optimized in the view of efficiency and economy. The result showed that the feasible concentration of RDP₃ was 1,000 mg/L.     

Absorptive Denitrogenation of Diesel Oil Using a Modified NaY Molecular Sieve

Y molecular sieve, modified by NH₄⁺, Zn²⁺, Cu²⁺, or Cr³⁺, were characterized by X-ray diffraction, infrared spectrum, and nitrogen adsorption, and used to adsorb denitrogenation from model fuel containing quinoline and diesel oil. The molecular size of quinoline, calculated by using density functional theory, was 7.116×5.002 Å, implying that it does not access easily to 7.4 Å microporous pores of Y molecular sieve. The adsorption denitrogenation of CrY was the best due to some mesoporous pores, followed by CuY, ZnY, and NH₄Y, implying that the absorption denitrogenation related to valence state metal ion, the better adsorption denitrogenation performance, the higher valence of metal ions. The basic nitrogen removal of diesel oil on CrY, CuY, ZnY, or NaY is 56.58%, 60.16%, 37.41%, and 23.72%, respectively.     

Microflora of traditional starter made from cassava for “attiéké” production in Dabou (Côte d’Ivoire)

Attiéké is a food made from cassava in Côte d’Ivoire by fermentation. The process uses a traditional starter. Studies on 81 starter samples from 3 villages showed that the dominant microflora consists of lactic acid bacteria (5.7 × 10⁷ cfu/g), yeasts (5.5 × 10⁷ cfu/g), Bacillus (3.8 × 10⁷ cfu/g), Enterococcus (3.0 × 10⁶ cfu/g), total coliforms (3.0 × 10⁶ cfu/g), thermotolerant coliforms (8.0 × 10³ cfu/g) and mould (2.0 × 10⁶ cfu/g). Lactic acid bacteria, Bacillus spp, yeasts, faecal Enterococci and moulds are organisms which could play a role in the cassava fermentation. Coliforms may indicate contamination from the environment during production.     

Treatment of drilling wastewater from a sulfonated mud system

Treatment of drilling wastewater from a sulfonated drilling mud system in the Shengli Oilfield, East China, was studied. The wastewater was deeply treated by a chemical coagulation-centrifugal separation-ozone catalytic oxidation combined process. The factors (i.e. pH value, chemical dosage, reaction time, etc.) influencing the treatment effect were investigated, and pH = 7 was determined as optimal for the coagulation; polymeric aluminum chloride (PAC) was selected as the optimal coagulant with a dosage of 18 g/L; cationic polyacrylamide (CPAM) with molecular weight of 8 million was selected as the optimal coagulant aid with an optimum dosage of 8 mg/L; and the optimal condition of catalytic ozonation was found to be a pH of 12 and an oxidation time of 40 min. The results showed that the combined treatment process was effective. The oil content and suspended solids content of the effluent reached the first class discharge standard according to China’s standard GB 8978-1996 (Integrated Wastewater Discharge Standard) and the chemical oxygen demand (COD) decreased to 195 mg/L from 2.34×10 4 mg/L after coagulation process and ozone oxidation at pH = 12 for 40 min.     

Incidence of pathogenic psychrotrophs in ice creams sold in some retail outlets in Mumbai,India

With a view to determine the microbial quality of ice creams, 30 samples of commercial brands of three flavours sold in the `open' and `packaged, (cone, cup)' forms were analyzed for their total bacterial counts (TBC), yeast and mold counts (YMC), coliforms and pathogenic psychrotrophs; Bacillus cereus, Staphylococcus aureus, Listeria monocytogenes, Yersinia enterocolitica and Salmonella spp. In general in both the types of ice creams bacterial load (2.3 × 10⁴–8.5 × 10⁶ cfu/ml) was higher; particularly coliform levels were 10–100 fold higher (3.0 × 10²–5.8 × 10⁴ cfu/ml) than the safety limits prescribed by Indian Standards Institute (ISI). Staph. aureus was detected in both the types of ice creams but occurrence of B. cereus was more frequent in open samples (40%) than in packed ones (26.6%). Salmonella was not detected in any of the 30 samples tested. While 53% of the packed and 100% of the open ice creams exhibited Listeria contamination, Yersinia were detected in 33% of packed and 40% of open ones. L. monocytogenes and/or Y. enterocolitica was detected only in one of the open ice cream samples. Growth profile of Y. enterocolitica 5692 and L. monocytogenes 036 at simulated temperature abuse conditions during commercial frozen storage showed that after 10 days L. monocytogenes could grow to >1 log and 1 log cycle at 8–10°C and 2–4°C, respectively and Y. enterocolitica grew 2 log cycles at both the temperatures. Results are discussed in the context of present microbiological specifications and the need for its implementation by regulatory agencies to ward off possible health hazards arising from pathogens.     

Geochemical characteristics and Thermal Evolution of Paleogene Source Rocks in Lunpola Basin,Tibet Plateau

Lunpola Basin is the first exploration area with industrial oil flow in the hinterland of Tibetan Plateau and the target horizon is the Paleogene Niubao formation and Dingqinghu formation. Based on drilling data from multiple wells, the organic matter abundance, type and maturity of Paleogene source rocks in Lunpola Basin were measured and analyzed using organic geochemistry method. The 67 samples data from middle Niubao formation show that the average of TOC (wt.) is 3.50, S₁+S₂ is 30.55?mg/g; and the Tmax is 427?～?442?°C, δ¹³CPDB is -25.6‰ ～ -29.3‰ and Ro is 1.37%～1.84%. The 53 samples data from upper Niubao formation show that the average of TOC (wt.) is 4.16%, S₁+S₂ is 30.16?mg/g. and the Tmax is 421?～?440?°C, δ¹³CPDB is -26.9‰ ～ -28.7‰ and Ro is 0.61%～1.35%. The 70 samples data from lower Dingqinghu formation show that the average of TOC (wt.) is 4.16%, S₁+S₂ is 30.16?mg/g and Ro is 0.58%, and the Tmax is 421?～?440?°C, δ¹³CPDB is -26.9‰ ～ -28.7‰. These three sets of source rocks have high organic abundance and kerogen type of I- II₁. Based on the previous studies of W-1 well in JiangjiaCo depression, XL-3 well in JiangriaCo depression and Z-1 well PaCo depression, a 2D model of north-south tectonic and thermal evolution in Lunpola basin is simulated by Schlumberger's PetroMod method. The results show that the XL-5 well of Niubao formation in Diezong area of Lunpola basin began to generate oil at 41.3Ma and reached the peak of hydrocarbon generation at 36.4Ma; and upper Niubao formation began to generate oil at 38.4Ma and hydrocarbon generation peaked at 31.9Ma. The lower Dingqinghu formation began to generate oil at 24.2Ma. At the end of upper Dingqinghu formation, the basin began the uplift and denudation stage at 23Ma, but the middle and upper Niubao formation and the Lower Dingqinghu formation are still active for hydrocarbon generation. The simulation also shows that the primary deposits in main source rocks are thin in the thrust uplift belt of southern basin and have not entered the stage of oil generation, and that the main oil source area is the Paleogene depression in central basin.     

Kinetics and physicochemical studies of surfactant enhanced remediation of hydrocarbons contaminated groundwater

Kinetics and physicochemical studies of surfactant enhanced remediation of hydrocarbons contaminated groundwater were investigated for efficiency and effectiveness. 10% pollution was simulated in the laboratory by contaminating groundwater samples with crude oil, automatic gasoline oil (diesel) and domestic purpose kerosene (DPK) in replicates of five. Physicochemical properties of the hydrocarbons contaminated groundwater samples and a control sample were investigated before and after treatments. Total petroleum (TPH) hydrocarbon as target contaminant was monitored periodically to assess the extent of the remediation process. TPH was determined by molecular spectrophotometry technique. Other physicochemical parameters such as pH, turbidity, alkalinity, dissolved oygen (DO), biochemical oxygen demand (BOD), chemical oxygen demand (COD), condutiivity, ammonia, nitrate, phosphate, salinity, total dissolved solids (TDS), total suspended solids (TSS) and total solids (TS) were obtained using standard methods while heavy metals levels were determined by atomic absorption spectrophotometry. Different kinetics models were tested to determine the appropriate kinetics model. The pseudo-first order kinetics is established with rate constant as 1.80 × 10⁴; 1.78 × 10⁴; 1.53 × 10⁴ mg^?1 L h^?1 for crude oil, diesel and kerosene respectively at 30 °C. At the end of the remediation after 6 h there was 89.11%; 93.21%; 87.76% reduction in TPH as crude oil, diesel and kerosene for the treated samples in that order. The application of surfactant enhanced remediation using sodium dodecyl sulphate is found be very efficient, effective and rapid in reducing total petroleum hydrocarbon as crude oil, kerosene and diesel as target contaminants. There is the need for post-treatments after remediation for most of the physicochemical parameters are impaired and do not meet the Guideline and Standards for Environmental Pollution Control in Nigeria set by Federal Ministry of Environment and World Health Organization for drinking water and agricultural uses in order to make them fit for these purposes.     

EFFECTS OF HYDROTREATING COKER LIGHT GAS OIL ON FUEL QUALITY

ABSTRACT

Coker light gas oil (LGO) derived from Athabasca bitumen was hydrotreated in a fixed bed reactor using two commercial NiO-MoO₃/Al₂0₃ catalysts. The effect of temperature on product quality was investigated in a pilot plant between 330 and 390 °C at 12.4 MPa, space velocity of 0.5 Ir1 and 700 liter of hydrogen per liter of coker LGO (L/L). The product quality was monitored by ^I3C NMR spectroscopy, elemental analysis, density and distillation techniques.

The data showed that coker LGO can be hydrotreated using nickel-molybdenum catalysts at 350 °C, 0.5 h¹, 12.4 MPa and 700 L/L to meet the diesel product specifications, namely, 0.5 wt % sulfur, 20% aromatics and cetane index of 40. The cetane index improvement and aromatic saturation, which are affected by thermodynamic equilibrium at temperature higher than 370?°C, could reach 29 and 86% respectively. The cetane improvement was attributed to aromatic saturation and hydrocracking with hydrogen consumption ranging from 215-340 L/L. The Ketjenfine KF-840 catalyst was found slightly better performance than Procatalyse HR-348 catalyst.