Amount Of Carbonaceous Residue Research Articles

Characteristics of High-Carbon-Content Slag and Utilization for Coal-Water Slurry Preparation

Fine slag and coarse slag are the byproducts of the entrained-flow gasifier, which may contain a considerable amount of carbonaceous residue. In this study, the characteristics of slags (LHA, LHB, ...

Fast pyrolysis of muconic acid and formic acid salt mixtures

Lignocellulosic feedstocks are a potential renewable resource for the production of liquid fuels and chemicals. As a major by-product of the pulping industry, lignin is an underutilized source of organic carbon in lignocellulosic biomass. Residual lignin remaining in pulp after cooking of lignocellulosic biomass is typically removed during the bleaching stage of a pulping operation. This stage is composed of a sequence of steps including oxidation and alkaline extraction. Given that muconic acid and formic acid are formed during oxygen treatment of alkaline solutions of lignin, fast pyrolysis coupled with gas chromatography–mass spectrometry (Py–GC/MS) of alkali/alkaline earth salt mixtures of muconic acid and formic acid was employed to produce significantly deoxygenated products, such as cyclic ketones, hydrocarbons, aromatics, and phenolics. The cations investigated in this study were sodium, calcium, and magnesium to observe the difference in product distribution, volatile formation, and the formation of carbonaceous residue. The compounds observed after pyrolysis of the various salts suggest that along with the expected intramolecular condensation reactions, free radical reactions are likely occurring at the temperatures investigated explaining the observed alkylation and hydrogenation of the vapor products beyond deoxygenation which can be expected from reactive hydrogen formed by formate decomposition. Hydrogenation may also be occurring as a result of catalytic effects of the metal cations on the pyrolysis vapors. Pyrolysis of calcium muconate favors cyclic ketone formation almost exclusively, and when formate is added a 61wt% reduction in carbonaceous residue formation is observed at 550°C in a thermogravimetric analyzer (TGA) equipped with an evolved gas analyzer furnace (EGA). The highest yields of gaseous species were observed for the magnesium muconate–formate mixture, approximately 47wt%, while the least amount of carbonaceous residue was formed upon pyrolysis of the sodium muconate–formate mixture, both at 550°C in a TGA. The data suggests that pyrolysis at 550°C of sodium formate and oxidized lignin mixtures may be of interest for the production of aromatic compounds.

Structural and Dielectric Properties of PMN-PT (65/35) Bulk Ceramics Synthesized by Metal-Polymer Gel Auto Ignition Route

Ultra-fine PMN-PT (65/35) powder was synthesized following a polymer precursor based chemical synthesis technique. The auto-ignited powder containing negligible amounts of carbonaceous residue (∼0.6 wt%) could be sintered directly without any further calcination. A mixture of perovskite and pyrochlore phase was detected in the auto-ignited powder by XRD analysis. The amount of pyrochlore phase decreased with increasing the annealing temperature and pure perovskite phase was obtained in the sample at 950°C. Scanning electron microscopy of the uniaxially pressed and sintered samples revealed the rectangular shaped grains. The dielectric properties of the sintered pellets were measured at room temperature.

Influence of asphaltenes on coke formation during the thermal cracking of different Brazilian distillation residues

This research was conducted to allow the investigation on the influence of asphaltenes on coke formation, during the thermal cracking of atmospheric distillation residues, using thermogravimetry. Asphaltenes of five refinery atmospheric distillation residues, of different API gravity Brazilian crude oils, were isolated by the IP143 methodology. The original samples and the same samples, after asphaltenes extraction, were analyzed by thermogravimetry. It was observed that the heavier the sample, the higher was the contribution of the asphaltenes to the coke formation. The extracted asphaltenes were analyzed under the same TG conditions of the atmospheric distillation residues and all asphaltenes appeared to form approximately the same amount of carbonaceous residue after the thermal cracking. Heavier and lighter atmospheric distillation residues were doped with 10%, 20% and 30% amount of asphaltenes and, again, the higher the asphaltenes amount, the higher would be the carbonaceous material formation. The same tendency was observed for both doped samples.

Tungsten permanent chemical modifier for fast estimation of Se contents in soil by graphite furnace atomic absorption spectrometry.

A tungsten carbide coating on the integrated platform of a transversely heated graphite atomizer was used as a modifier for the direct determination of Se in soil extracts by graphite furnace atomic absorption spectrometry. Diethylenetriaminepentaacetic acid (0.0050 mol L(-1)) plus ammonium hydrogencarbonate (1.0 mol L(-1)) extracted predominantly available inorganic selenate from soil. The formation of a large amount of carbonaceous residue inside the atomizer was avoided with a first pyrolysis step at 600 degrees C assisted by air during 30 s. For 20 microL of soil extracts delivered to the atomizer and calibration by matrix matching, an analytical curve (10.0-100 microgram of L(-1)) with good linear correlation (r = 0.999) between integrated absorbance and analyte concentration was established. The characteristic mass was approximately 63 pg of Se, and the lifetime of the tube was approximately 750 firings. The limit of detection was 1.6 microgram L(-1), and the relative standard deviations (n = 12) were typically <4% for a soil extract containing 50 microgram of L(-1). The accuracy of the determination of Se was checked for soil samples by means of addition/recovery tests. Recovery data of Se added to four enriched soil samples varied from 80 to 90% and indicated an accurate method.

Thermostable Insulating Thermoplastic Elastomers from Rubber Polycarbonate Blends

Thermoplastic elastomeric blends based on polycarbonate (PC) (30 parts) and elastomers (70 parts) of varying polarity, e.g., ethylene propylene diene rubber (EPDM), chlorinated polyethylene (CPE), nitrile rubber (NBR), hydrogenated nitrile rubber (HNBR), acrylic rubber (ACM) have been studied and characterized by various methods, e.g., stress-strain measurement, surface energy estimation, thermogravimetric analysis, dynamic mechanical analysis and volume resistivity measurement. The highest tensile strength and best processability are found to be attained with the CPE/PC and HNBR/PC blends. The surface energy mismatch is also low for these systems. EPDM/PC and HNBR/PC offer excellent thermal stability. The amount of carbonaceous residue is found to depend on the elastomer structure present in the blend. The activation energy for degradation lies in the range of 210-320 kJ/mol and the order of reaction in the range of 0.8-1.2. Dynamic mechanical analysis shows existence of two separate glass transition temperatures (T.) classically associated with an immiscible system. The values of elastic modulus display a sharp change in magnitude in the vicinity of glass-rubber transition temperature and follow a linear relationship with frequency. The apparent activation energy for glass rubber transition of the blends lies in the range of 275-296 kJ/mol and that for high temperature relaxation of the polycarbonate phase lies in the range of 563-590 kJ/mole. All the blends show good electrical insulation characteristics. The amount of polycarbonate in the blend exerts a profound influence on the volume resistivity. The level of unsaturation and the polarity of the elastomer phase also affect the resistivity values.