Characterization of products from slow pyrolysis of palm kernel cake and cassava pulp residue

Slow pyrolysis studies of palm kernel cake (PKC) and cassava pulp residue (CPR) were conducted in a fixed-bed reactor. Maximum liquid yield (54.3 wt%) was obtained from PKC pyrolysis at 700 °C, heating rate of 20 °C/min, N₂ gas flow rate of 200 cm³/min and particle size of 2.03 mm. Fuel properties of bi-oils were in following ranges: density, 1.01–1.16 g/cm³; pH, 2.8–5.6; flash point, 74–110 °C and heating value, 15 MJ/kg for CPR oil and 40 MJ/kg for PKC oil. PKC oil gave main contents of n-C₈–C₁₈ carboxylic acids, phenols, and esters, whereas CPR oil gave the highest amount of methanol soluble fraction consisting of polar and non-volatile compounds. On gas compositions, CPR pyrolysis gave the highest yield of syngas produced, while PKC pyrolysis offered the highest content of CO₂. Pyrolysis chars possessed high calorific values in range from 29–35 MJ/kg with PKC char showing a characteristic of reasonably high porosity material.     

Optimum condition of membrane electrode assembly fabrication for PEM fuel cells

The aim of this research was to study the effect of fabrication factors on the performance of MEA of a PEM fuel cell. The MEA was prepared by using 5 cm² of porous electrodes with Pt loading 1 mg/cm² and Nafion 115 membrane from Electrochem Co. Ltd. The studied factors were temperature, pressure and time of compression in the range of 130–150 ‡C, 50–100 kg/cm² and 1–5 minutes, respectively. A 2^k factorial design was conducted in this study. The results showed that interaction between pressure and temperature and interaction between temperature and time of compression have significant effects on the performance of the MEA. With low pressure, but high temperature and long compression time, current density is increased. The results showed that the optimum condition was 65 kg/cm², 137 ‡C and 5.5 min of compression time. It was also found that the force of 69 kg-cm for assembling the single cell gave the best performance.     

Deacidifying rice bran oil by solvent extraction and membrane technology

Crude rice bran oil containing 16.5% free fatty acids (FFA) was deacidified by extracting with methanol. At the optimal ratio of 1.8:1 methanol/oil by weight, the concentration of FFA in the crude rice bran oil was reduced to 3.7%. A second extraction at 1:1 ratio reduced FFA in the oil to 0.33%. The FFA in the methanol extract was recovered by nanofiltration using commercial membranes. The DS-5 membrane from Osmonics/Desal and the BW-30 membrane from Dow/Film Tec gave average FFA rejection of 93–96% and an average flux of 41 L/m²·h (LMH) to concentrate the FFA from 4.69% to 20%. The permeate, containing 0.4–0.7% FFA, can be nanofiltered again to recover more FFA with flux of 67–75 LMH. Design estimates indicate a two-stage membrane system can recover 97.8% of the FFA and can result in a final retentate stream with 20% FFA or more and a permeate stream with negligible FFA (0.13%) that can be recycled for FFA extraction. The capital cost of the membrane plant would be about $48/kg oil processed/h and annual operating cost would be about $15/ton FFA recovered. The process has several advantages in that it does not require alkali for neutralization, no soapstock nor wastewater is produced, and effluent discharges are minimized.     

Investigation of phase transitions in glyceride/paraffin oil mixtures using ultrasonic velocity measurements

A pulse echo technique has been used to measure the ultrasonic velocity of a number of 15% w/w glyceride/paraffin oil mixtures with increasing temperature (0–70 C). At the lower temperatures the glycerides are completely solid and there is a fairly steady decrease in velocity with temperature (ca. −3.8 ms⁻¹C⁻¹). As the temperature rises the glycerides become increasingly soluble in the paraffin oil and the velocity decreases more rapidly. Once the glyceride is completely soluble in the paraffin oil, a fairly steady decrease in velocity with temperature (ca. −3.3 ms⁻¹C⁻¹) resumes. The dependence of ultrasonic velocity on the amount of solid glyceride present means the technique can be used to investigate phase transitions in binary glyceride/oil mixtures.     

Application of a Handheld Portable Mid-Infrared Sensor for Monitoring Oil Oxidative Stability

This study evaluated the capabilities of a handheld mid-infrared (MIR) spectrometer combined with multivariate analysis to characterize oils, monitor chemical processes occurring during oxidation, and to determine fatty acid composition. Vegetable oils (corn, peanut, sunflower, safflower, cottonseed, and canola) were stored at 65 °C for 30 days to accelerate oxidation reactions. Aliquots were drawn at 5 day intervals and analyzed by benchtop and portable handheld mid-infrared devices (4,000–700 cm⁻¹) and reference methods (IUPAC 2301 [1], 2302 [1]; AOCS Cd 8-58 [2]; and Shipe 1979 [3]). PLSR and soft independent modeling of class analogy (SIMCA) models were developed for oil classification and estimation of oil stability parameters. Models developed from MIR spectra obtained with a benchtop spectrometer equipped with a 3-bounce ATR device resulted in superior discriminative performances for classifying oils as compared to those obtained from handheld spectra (single-bounce ATR). Models developed from reference tests and handheld spectra showed prediction errors (SECV) of 1 meq/kg for peroxide value, 0.09% for acid value and 2% for determination of unsaturated fatty acids in different oils. Spectral regions ~3,012–2,850 cm⁻¹ (C–H stretching bands/shoulders of fatty acids), ~1,740 cm⁻¹ (C=O stretching of esters), and ~1,114 cm⁻¹ (–C–O stretching) were found to be important for prediction. Handheld-FTIR instruments combined with multivariate-analysis showed promise for determination of oil quality parameters. Portability and ease-of-use makes the handheld device a great alternative to traditional methods.     

Flavor and oxidative stability of continuously hydrogenated soybean oils

Soybean oil was partially hydrogenated in a continuous system with copper and nickel catalysts. The hydrogenated products were evaluated for flavor and oxidative stability. Processing conditions were varied to produce oils of linolenate contents between 0.4 and 2.7%, as follows: oil flow, 0.6–2.2 liters/hr; reaction temperature, 180–220 C; hydrogen pressure, 100–525 psig, and catalyst concentration, 0.5–1% copper catalyst or 0.1% nickel catalyst.Trans unsaturation varied from 8 to 20% with copper catalyst and from 15.0 to 27% with nickel catalyst. Linolenate selectivity was 9 with copper catalyst and 2 with nickel catalyst. Flavor evaluation of finished oils containing 0.01% citric acid (CA), appraised initially and after accelerated storage at 60 C, showed no significant difference between hydrogenated oils and nonhydrogenated oil. However, peroxide values and oxidative stability showed that hydrogenated oils were more stable than the unhydrogenated oil. CA+TBHQ (tertiary butylhydroquinone) significantly improved the oxidative stability of test oils over oils with CA only, but flavor scores showed no improvement. Dimethylpolysiloxane (MS) had no effect on either flavor or oxidative stability of the oils.     

Influence of operating variables on yield and quality parameters of olive husk oil extracted with supercritical carbon dioxide

Supercritical fluid extraction is a viable alternative process for extracting oil from olive husk, a residue obtained in the olive oil production. We analyzed the effects of pressure (P) (100–300 bar), temperature (T) (40–60°C), solvent flow (1–1.5 L/min), and particle size (D) (0.30–0.55 mm) on extraction yield, and three oil-quality parameters: acidity (OA), PV, and phosphorus content (PC). A response surface methodology based on the statistical analysis of the experimental data permitted us to obtain mathematical expressions relating the operational variables and parameters studied. At the best extraction condition of the experimental range analyzed (P=300 bar, T=60°C, D=0.30 mm, and solvent flow=1.25 L/min at standard conditions), the oil yield was 80% (w/w) with respect to hexane extraction, whereas the quality parameters OA, PV, and PC were 14% (w/w), 8 meq/kg, and 2.3·10⁻³% (w/w), respectively. These results were compared to those obtained by hexane Soxhlet extraction. The quality of the supercritical extract was superior, requiring only simple refining. This advantage may result in improved economics of the supercritical process in relation to the conventional extraction with hexane.     

Studies of some operating parameters and cyclic voltammetry for a direct ethanol fuel cell

A direct ethanol fuel cell (DEFC) of 5 cm² membrane-electrode area was studied systematically by varying the catalyst loading, ethanol concentration, temperature and different Pt based electro-catalysts (Pt–Ru/C, Pt-black High Surface Area (HSA) and Pt/C). A combination of 2 M ethanol at the anode, pure oxygen at the cathode, 1 mg cm⁻² of Pt–Ru/C (40%:20%) as the anode and 1 mg cm⁻² of Pt-black as the cathode gave a maximum open circuit voltage (OCV) of 0.815 V, a short circuit current density of 27.90 mA cm⁻² and a power density of 10.3 mW cm⁻². The optimum temperatures of the anode and cathode were determined as 90 °C and 60 °C, respectively. The power density increased with increase in ethanol concentration and catalyst loading at the anode and cathode. However, the power density decreased slightly beyond 2 M ethanol concentration and 1 mg cm⁻² catalyst loading at the anode and cathode. These results were validated using cyclic voltammetry at single electrodes under similar conditions to those of the DEFC.     

Combustion of pressed specimens of heterogeneous systems subjected to a constant axial mechanical load

The growth dynamics of the height of burning pressed specimens with the specimen ends subjected to a compressive force of constant magnitude is studied using the heterogeneous Ti+C+20% TiC system as an example. It is found that in the examined range of compressive forces 0.1–2 kg/cm², the growth of the height of the burning specimens with time obeys a linear law; under a compressive force of ≈0.1 kg/cm², the specimen height increases by ≈100%, and under a force of ≈2 kg/cm², it increases by about 25%. The method used to measure the growth dynamics of the specimen height during combustion proved a useful tool for the experimental determination of both the burning time of the specimens and the delay in the transfer of combustion through an obstacle. __________ Translated from Fizika Goreniya i Vzryva, Vol. 43, No. 3, pp. 103–109, May–June, 2007.     

Furfural production by acid hydrolysis and supercritical carbon dioxide extraction from rice husk

The aim of this research was to study the effect of furfural production from rice husk by hydrolysis accompanying supercritical CO₂ (SC-CO₂) extraction. The two-level fractional factorial design method was used to investigate the production process carried out with respect to furfural yield. The process variables are temperature range of 373–453 K, pressure 9.1–18.2 MPa, CO₂ flow rate 8.3 × 10⁻⁵–1.7 × 10⁻⁴ kg/s (5–10 g/min), sulfuric acid concentration 1 to 7 (%wt) and ratio of liquid to solid (L/S) 5 : 1 to 15 : 1 (vol/wt). The results obtained from the experimental design showed that increasing temperature, pressure, CO₂ flow rate and sulfuric acid concentration but decreasing ratio of liquid to solid would improve furfural yield. Moreover, furfural production by two-stage process (pre-hydrolysis and dehydration) can improve furfural yield further to be around 90% of theoretical maximum.     

Determination of phosphorus in edible oils by inductively coupled plasma—Atomic emission spectrometry and oil-in-water emulsion of sample introduction

The determination of phosphous was carried out using emulsion sample preparation followed by analysis by inductively coupled plasma-atomic emission spectrometry. The optimal oil-in-water (o/w) emulsion and surfactant concentrations were found by applying response surface methodology. Two phosphorus emission lines were tested. Ethoxynonylphenol was a good choice for the emulsion preparation. The optimal concentration for the oil in the o/w emulsion and the surfactant concentrations were ca. 8.0–37% w/w and ca. 1.0–10% w/w ethoxynonylphenol, respectively, for the 213.620 nm line; and an oil phase emulsion concentration between ca. 18–32% w/w and ca. 3–8% w/w ethoxynonylphenol for the 214.911 nm emission line. Good agreement was found between calibration curves for emulsified aqueous standards solutions and o/w emulsions. The use of aqueous standards for calibration purposes is a good addition in the analysis of this type of oil sample where certified standards are not available. Recoveries ranged from 98 to 105% and from 102 to 116% for the 213 and 214 nm lines, respectively with relative standard deviations lower than 7%.     

Preparation of tertiary amine derivatives from commercially available alcohols and their properties as surfactants

Higher tertiary amines were prepared by transalkylation of triethylamine with commercially available alcohols such as Tergitol 15-S-3 and tridecyl alcohol. This reaction carried out at 250–300 C and 20 kg/cm² initial hydrogen pressure, using Cu−Cr−Mn−O catalyst, gave about 80% yield of higher alkyl tertiary amines. Tertiary amine hydrochlorides, quaternary ammonium bromides and amine oxides were prepared from these tertiary amines. Specific surface tension, wetting power, foaming power and foam stability were measured. The characteristic properties with respect to tertiary amine derivatives containing ether linkages were observed. These products have excellent wetting power, reduced surface tension, low foaming power and unstable foam.     

The properties and performance of poly AO™-79; A nonabsorbable,polymeric antioxidant intended for use in foods

The physical, chemical, and biological characteristics of Poly AO™-79, a composition selected from a class of polymers prepared by the polycondensation of divinylbenzene and a blend of various sterically hindered phenols and hydroquinone, are discussed. Data are presented indicating that Poly AO™-79 demonstrates excellent antioxidant activity in stabilizing vegetable oils when compared to monomeric food grade antioxidants [butylated hydroxytoluene (BHT), butylated hydroxyanisole (BHA), and tertiary butylhydroquinone (TBHQ)] as measured by the active oxygen method (AOM) and oxygen bomb test. Stability tests using thermogravimetric analysis indicate that the material is not depolymerized in the presence of air at temperatures up to 300 C while BHT, BHA, and TBHQ are completely volatilized at 150–170 C. Using¹⁴C-radiolabeled antioxidants, the physical losses of Poly AO™-79 from frying oil heated to 190 C is nil while 65% and 80% losses are incurred with BHA after 1 and 2 hr holding time, respectively. The physical carry-through of Poly AO™-79 onto potatoes from frying oil at 190 C is quantitative as compared to ca. 20% losses with BHA and TBHQ. Sensory panel tests reflect that the carry-through of Poly AO™-79 is in an active form as evidenced by the prolonged shelf-life of chips fried in oil containing Poly AO™-79 as compared to BHA and TBHQ. Rats and mice orally dosed with¹⁴C-radiolabeled antioxidants indicate that Poly AO™-79 is virtually not absorbed from the gastrointestinal tract (ca. 0.2–0.6%) while monomeric antioxidants are readily transported (80–100%). Acute oral and intraperitoneal toxicity tests indicate that Poly AO™-79 is without effect at the highest dose tested (10 g/kg body weight). Presented at the AOCS Meeting, Chicago, September, 1976.     

Production of low ash coal by thermal extraction with <Emphasis Type="Italic">N</Emphasis>-methyl-2-pyrrolidinone

Present study was conducted for the purpose of producing low ash coal from LRC (low rank coals) such as lignite and sub-bituminous coal through thermal extraction using polar solvent. Extraction from bituminous coal was also investigated for comparison. NMP as a polar solvent was used. The ratio of coal to solvent was adjusted as 1: 10. Experimental conditions were established which include the extraction temperature of 200–430 °C, initial applied pressure of 1–20 bar and extraction time of 0.5–2 hr were used. Extraction yield and ash content of extracted and residual coal were measured. The extraction yield increased with the increase of extraction temperature, and the ash content of extracted coal decreased below 0.4% at 400 °C from the raw coal samples that have the ash contents of 4–6%. According to the analysis of experiments results, fixed carbon and calorific value increased, and H/C and O/C decreased.     

Simple high vacuum distillation equipment for deodorizing fish oil for human consumption

A simple piece of glass equipment for deodorizing fish oil (sardine oil) by high vacuum distillation was designed and constructed. The equipment has a throughput of 450–500 ml/hr working at 140°C and at a constant pressure of 2×10⁻² mm Hg. It reduces the peroxide value and the cholesterol content of the oil and improves the flavor without affecting the EPA and DHA content.     

Farm-scale recovery and filtration characteristics of sunflower oil for use in diesel engines

The “Hander,” new Type 52 oil expeller was evaluated to determine its performance in expressing sunflower oil for use in diesel engines. Strain gauges were mounted on the barrel of the expeller and were used to give a relative indication of barrel pressure. Relative barrel pressure was then used as the independent variable in determining performance. Filterability of four commercial sunflower oils and blends of these oils with No. 2 diesel fuel were determined at various temperatures and pressures. Oil extraction efficiency ranged from ca. 56% to 84% at low and high relative barrel pressures, respectively. The greatest oil extraction rate was 12.3 kg/hr at a feed rate of 40 kg/hr with an extraction efficiency of ca. 80%. Dewaxed sunflower oils and blends filtered much better than nondewaxed oils and their blends. Increasing temperature, pressure and percentage of diesel fuel in the blends increased filterability of dewaxed sunflower oil. Work on this project is supported by North Dakota Agricultural Experiment Station Project 1439.     

Alkaline peroxide generation using a novel perforated bipole trickle-bed electrochemical reactor

A novel perforated bipole trickle-bed electrochemical reactor is investigated for the electro-synthesis of alkaline peroxide. The process uses a relatively simple cell configuration in which a single electrolyte flows with oxygen gas in a flow-by graphite felt cathode, sandwiched between a micro-porous diaphragm and a perforated bipolar electrode plate. The graphite felt cathodes are 120 mm high by 25 mm wide and have a thickness of 3.2 mm. The reactor is operated at current densities in the range 1–5 kA m⁻², ca. 800 kPa (abs) pressure and temperature (In/Out) 20–45 °C with one and two-cells. The reactor shows good performance (current efficiency ∼78% at 2 kA m⁻² and a specific energy of 5 kWh per kg of peroxide generated) with peroxide concentrations from 0.02 to 0.15 M in 1 M NaOH.     

Rheology and stability of phospholipid-stabilized emulsions

Lecithin in cosmetic emulsions produces a unique “skin feel,” which can be related to its rheological properties. In this study, water-in-oil (w/o) and oil-in-water (o/w) emulsions were made from a cosmetic-grade caprylic/capric triglyceride with deoiled lecithin and hydroxylated lecithin. Synthetic surfactants commonly used in commercial cosmetic products were used as controls. Optical light microscope investigation showed significant differences in the structures of the w/o and o/w emulsions made with the lecithins. Freeze/thaw tests were conducted to evaluate emulsion stability. The o/w emulsion (oil/water = 20:80) was stable with 3% hydroxylated lecithin at room temperature. However, 4% hydroxylated lecithin was needed for stabilizing the emulsion with an oil-to-water ratio of 20:80 or 30:70 through the freeze/thaw treatments. With 4% deoiled lecithin, the w/o emulsion showed a water-holding capacity up to 80%, which was also stable through two freeze/thaw cycles. All emulsions in this study exhibited pseudoplastic flow, in which a minimum shearing stress, a yield value, was required before flow became linear. In general, the emulsion viscosity increased as lecithin content increased. Changing the oil-to-water ratio also affected the emulsion viscosity. The deoiled lecithin-based w/o emulsions had higher yield values than hydroxylated lecithin-based o/w emulsions. Therefore, more force was needed to spread the w/o emulsions. In addition, because w/o emulsions had more viscous continuous phases and a greater volume of internal phases, the w/o emulsions were more viscous than the o/w emulsions.     

Physico-chemical properties of silica aerogels prepared from TMOS/MTMS mixtures

In the present work, results on the physico-chemical properties of the silica aerogels prepared by sol–gel process using mixtures of TMOS and MTMS as precursor are reported. The wide range of precursor mixture was studied with ratio of MTMS/TMOS in precursor mixtures as 0:100, 25:75, 50:50, 75:25, and 100:0 by volume. The gels with these precursor mixtures were successfully prepared using two step acid–base catalysis for gelation. Acetic acid (0.001 M) and NH₄OH (1.5 M) were used for catalysis and resulting alcogels were subsequently dried by supercritical solvent extraction method. FTIR spectroscopy revealed that the aerogels show more intense peak at 1,260 and 790 cm⁻¹ attributed to Si–CH₃ resulting in more hydrophobic nature and these results were concurrent with adsorbed water content measurements made using Karl Fischer’s titration technique. The resulted aerogels were characterized using differential thermal analysis, thermo gravimetric analysis and surface area measurements. The surface area measurements showed an interesting trend that the surface area increased from 395 to 1,037 m²/g with increase in MTMS content in the precursor mixture from 0 to 50% and then again decreased to 512 m²/g for further increase in MTMS content from 50 to 100% in the precursor mixture. It was observed from our studies that silica aerogels prepared using a starting mixture of 50% TMOS and 50% MTMS resulted in high moisture resistance (adsorbed water content of 0.721% w/w), low density of 90 kg/m³ and the highest surface area of 1,037 m²/g, which has great potential for catalysis support applications.     

Enzymatic Extraction of Wheat Germ Oil

In this study enzymatic extraction of oil from wheat germ (WG) was investigated. Four enzymes (Viscozyme L, Multifect CX 13L, Multifect CX GC and Alcalase 2.4L FG) were screened for their efficacy to release oil from WG. Alcalase 2.4L FG treatment of WG improved oil extraction yield as compared to a control (aqueous extraction without enzyme). Alcalase 2.4L FG, which resulted in significantly higher oil yield than the other three enzymes, was chosen for optimization of the enzymatic oil extraction process by using Response Surface Methodology (RSM). Three processing parameters, liquid/solid ratio, extraction time and enzyme concentration, were investigated as the independent variables. Based on the experimental results, the highest oil yield, 66.5% (w/w), was obtained under the following conditions; liquid/solid ratio 16.5, enzyme concentration 1.1% and extraction time 19.25 h. A cubic model with R ² of 0.91 was developed to describe the enzymatic extraction process. Although the cubic model predicted WG oil extraction yields well within the processing conditions studied in this study it was not effective beyond the experimental range. Further research focusing on high liquid/solid ratio, 16–20, and extraction time in 18–24 h and 0.5–5 h ranges is necessary to improve the model developed in this study.