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The disposal of sulfite-rich flue gas desulfurization (FGD) scrubber sludge has been a tough problem. The sludge now finds its prospective utilization way by being transformed into α-calcium sulfate hemihydrate (α-HH). At low pH, atmospheric pressure and 95.0°C, the calcium sulfite hemihydrate (CSH) is oxidized and then changed to α-HH via calcium sulfate dihydrate (DH) in 2.50–3.50m CaCl2 solutions...
The mitigation of potential global warming due to the emission of greenhouse gases, especially CO2, would require large-scale geological sequestration. Though current emphasis has been on identifying and characterizing the potential geological sequestration reservoirs, there is also an urgent need to ensure that the sequestered CO2 will remain in place under reasonable perturbations, e.g., under seismic...
The main objective of this study is to determine the effect of thermal cracking on asphaltene molecular structure. Hence, n-heptane insoluble fractions were precipitated and collected from three different vacuum residues and their thermally decomposed products. The X-ray diffraction (XRD) analysis provided an understanding of the macro-structure of the asphaltene molecule and revealed the impact of...
Using biomass as a source of energy has been gradually increasing in last decades, because it is a sustainable and CO2 neutral fuel. In order to improve the performance of gasifiers, academic and industrial researches need to gain insights into the highly complex processes during the combustion of biomass. Even though many research has been already done in this field, the detailed mechanisms during...
Indonesian lignite was continuously modified in a tunnel-type microwave oven to improve its slurribility. The maximum solid concentration of coal–water slurry (CWS) prepared from modified lignite increased from 41.6wt.% to 54.0wt.% with an enhanced rheological behaviour. The contact angle, oxygen functional groups, molar ratio of methylene to methyl, paramagnetic centres of modified lignite were analysed...
This paper investigates the flame size (i.e. envelop surface area and flame volume) and the volumetric heat release rate of turbulent jet diffusion flames, in both normal and in a sub-atmospheric pressure. Experiments on turbulent jet diffusion flames, produced with nozzles of 4, 5, 6 and 8mm in diameter and using propane as fuel, have been carried out at two different altitudes: Hefei, 50m and 100kPa...
In this study, pyrolysis of hornbeam (Carpinus betulus L.) shell residues was investigated to determine the optimum pyrolysis conditions and the physical and chemical characteristics of bio-oil and bio-char. Experiments were performed at the pyrolysis temperatures of 400, 450, 500, 550 and 600°C, heating rates of 7, 15, 30 and 50°Cmin−1 and nitrogen flow rates of 50,100 and 150cm3min−1. The highest...
The aim of this work was to optimize the production of fatty acid methyl esters (FAMEs, biodiesel) from marine Nannochloropsis gaditana wet microalgal biomass (25wt% dry biomass and 11.1wt% saponifiable lipids, SLs, of dry biomass) by direct acid catalyzed methylation of SLs in the microagal biomass and extraction of FAMEs with hexane. The best FAME yield was attainted with a methanol/SL ratio of...
The salts present in petroleum interfere in the characterization of its physicochemical properties, and from the measurements of these properties is established the price of crude oil. Therefore the water and salt need to be removed before these analyses. A new desalting apparatus was developed for heavy crude oils desalination by using demulsifier with water. The desalination process is accomplished...
The present study aims to evaluate the chemical and mineralogical compositions of coal samples collected from three different seams of a particular borehole of Samaleswari Block, Ib river coalfield, Odisha, India. Different experimental and theoretical studies were conducted to predict and correlate the chemical and mineral composition of coal ash to ash fusion temperatures. The experimental techniques...
Advances in combustor technologies are driving aircraft gas turbine engines to operate at higher pressures, temperatures and equivalence ratios. A viable approach for protecting the combustor from the high-temperature environment is to inject air through the holes drilled on the surfaces. However, it is possible that the air intended for cooling purposes may react with fuel-rich combustion products...
Gasification is a key process of chemical and energy industry. In order to improve the economic feasibility of gasifiers, new refractory lining materials with a long service life have to be developed, which can substitute the currently used high chromia bricks. TiO2 and ZrO2 were added to an Al2O3-refractory in order to improve its thermal shock and corrosion resistance against molten slags. Next...
Nitric oxide (NO) is an atmospheric pollutant responsible for the destruction of the ozone layer and the creation of photochemical smog. As a result, NOx emissions from combustion sources are regulated in most industrialised countries. The need to control NOx emissions while also promoting more efficient use of fossil energy resources requires a better understanding of combustion processes, especially...
Most of the time, spark ignition (SI) engine performance is limited by knock phenomena (especially for turbocharged engines), which are linked to fuel resistance to auto-ignition, quantified by its octane number (Research Octane Number – RON and Motor Octane Number – MON). If high octane numbers are crucial for efficient high load operating points, they are less necessary at low load. Thus, if the...
In this paper, we study the robust observer design problem for removal of NOx sensor ammonia cross-sensitivity from contaminated measurements in Diesel-engine selective catalytic reduction (SCR) systems via the mixed H2/H∞ approach. Due to the fact that the NOx sensor is cross-sensitive to gaseous ammonia, the reading of NOx sensor is contaminated severely by the ammonia concentration. Moreover, the...
This paper first of all summarized the auto-ignition mechanism of high cetane and high octane number fuels from the aspect of chemical reaction kinetics with the main purpose of explaining different auto-ignition characteristics of the two kinds of fuel and providing a classification of fuels with the same ignition principles. High cetane number fuels cover major real compression-ignition internal...
To accelerate progress in the industrial use of RDF as an alternative fuel in gasification plants, the problems associated with hazardous solid residues and ash deposition must be resolved. The practical approach to reduce these problems must be aimed at preventing the accumulation of fly ash/condensable vapours on heat transfer surface areas while minimising the amount of residual materials that...
In this work, an efficient heterogeneous acid catalyst for the esterification of oleic acid was prepared directly from oilseed cake by a simple sulfonation with concentrated H2SO4. Characterization by SEM/EDS, IR, Raman, TG, TG/MS, potentiometric titration showed that treatment with H2SO4 for 1, 2 and 4h at 120°C partially dehydrates the cake to form a carbon/cellulose composite which is sulfonated...
An attempt was made to investigate potential synergistic activities between waste tyre and lignite during co-pyrolysis. The parameters such as blending ratios of waste tyre and lignite, final pyrolysis temperature, heating rates and reactor types were optimized in the experiments. The characteristics of pyrolysis products were determined by using FTIR, 1H-NMR, GC–MS and elemental analysis. The results...
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