Volume 16 - 2014

Iron and steel industry generates substantial amount of inorganic solid wastes namely blast furnace (BF), Linz-Donawitz (LD) slag from the metallurgical process and fly ash from thermal power plant which creates environmental pollution when dumped in open land. In this investigation, BF and LD slag are incorporated in quartz free fly ash based porcelain system and changes in their properties, phase and microstructural evolution were studied. The samples shown very high flexural strength (>50 MPa) in the temperature range of 1200-1300 °C. Appearance of anorthite crystals were observed when feldspar is gradually replaced by BF and LD slag.  The body with a combination of BF slag and feldspar possesses the highest strength (90 MPa) due to the presence of mullite grains and fewer fracture origins caused by large difference in the thermal expansion coefficient between the glassy matrix, quartz and anorthite grains during cooling process. Total replacement of feldspar by equal percentage of BF and LD slag resulted formation of almost 100% anorthite grains with distinct change in crystal morphology. A strong pre-stress is produced on the glassy phase that surrounds the anorthite grains by the large difference in thermal expansion coefficient between the glassy phase and anorthite grain.

Several adsorbents have been tried out by researchers to remove different pollutants from wastewater. However, the adverse effect of these biosorbents on the treated water and the possibility of leaching new pollutants to the treated water have not been investigated.  A batch technique was employed to study this phenomenon. Three agricultural wastes namely sawdust, dates stones and palm fibers were investigated. The possible leaching of total dissolved solids (TDS) and organic compounds in the form of chemical oxygen demand (COD) from these substances to water were investigated. The effect of water pH and particle size of these biosorbents on the extent of the leaching process was studied. The results indicate high release of both TDS and COD for the three biosorbents. A COD value as high as 230 mg l^-1 was obtained, while the highest TDS leached was 29 mg l^-1. DS was found to have the highest leaching ability, followed by SD and PF. The highest leaching was obtained at high pH and small particle size of the adsorbent.

An unstandarised biodiesel made from Camelina sativa oil, having over a 90 percent by weight of unsaturated fatty acids, were transformed into an epoxidised biodiesel that satisfy the requirements for iodine value, linolenic acid methyl ester content, cetane number, polyunsaturated fatty acids content, and viscosity established by the EN 14214 and ASTM D 6751 standards. The epoxidation reaction was carried out at 60 °C using peroxyacetic acid generated in situ and sulphuric acid as catalyst. A conversion of 60 % of double bonds was reached after 3 hours of reaction. However, only one hour was needed to get standard requirements and to avoid the epoxide ring opening side reaction that leads to hydroxyl groups. Besides, it was also observed that the formation of hydroxyl groups increases the kinematic viscosity of the biodiesel, being deleterious for the biodiesel properties. 

A set of experiments have been carried out in a heavy duty single cylinder engine using high EGR rates and different start of injection angles (SOI). Three different fuels (conventional diesel fuel, a diesel-ethanol mixture (e-diesel) and a Fischer-Tropsch fuel (GTL)) have been tested in order to evaluate their potential to achieve Low Temperature Combustion (LTC) conditions. Diesel and e-diesel have shown poor repeatability for the most delayed angle (4 deg aTDC) due to significant cycle-to-cycle variations. GTL has shown a heat release rate pattern typical of conventional diesel combustion for all the SOI values, while diesel and e-diesel show fully premixed combustion for delayed SOI (from 4 deg bTDC). A delay of SOI causes a decrease in the brake thermal efficiency and an increase in THC and CO emissions, the latter being more important when e-diesel is used. While late injection seems to considerably improve NOx emissions, no benefits have been obtained for diesel particles, maybe due to the low engine torque tested (which causes the soot production rate to be more significant than the oxidation rate). The low autoignition tendency together with the high volatility of ethanol makes e-diesel as a promising fuel to achieve LTC conditions while keeping acceptable fuel consumption and CO/THC emissions.