Iranica Journal of Energy and Environment (IJEE)

109 - 117

Authors: P. Venkateswara Rao, B.V. Appa Rao, D. Radhakrishna

An experimental investigation was carried out to evaluate the effect of using Triacetin (T) as an additive with biodiesel on direct injection diesel engine for performance and combustion characteristics. Normally in the usage of diesel fuel and neat biodiesel, knocking can be detected to some extent. By adding triacetin [C9H14O6] additive to biodiesel, this problem can be alleviated to some extent and the tail pipe emissions are reduced. Comparative study was conducted using petro-diesel, biodiesel and additive blends of biodiesel on the engine. Coconut oil methyl ester (COME) was used with additive at various percentages by volume for all load ranges of the engine viz. at no load, 25%, 50%, and 75% of full load and at full load. The performance is compared with neat diesel in respect of engine efficiency and exhaust emissions. Among the all blend fuels tried, 10% Triacetin combination with bio-diesel shows encouraging results.

123 - 128

Authors: Bharat Gami, Beena Patel

The power industry is confronting challenges with seemingly conflicting goals. They provide the economy of scale needed to minimize the cost of production. Consumers, including industry, rely on affordable, dependable electrical energy. It’s an important part of our economy and our daily lifestyle. However, reducing emission levels and conserving our finite resources are key components for achieving a sustainable environment. Biomass is a resource that can be substituted for coal, in varying degrees for existing pulverized coal plants. New, large power plants are being designed to utilize biomass as the primary fuel. Biomass is available now and biomass based new products and sources are being developed, as the market unfolds. However, fuel properties and characteristics are important to boiler design and operation. Different boilers have unique design and fuel requirements. Heating value, percent volatiles, total ash and moisture content, ash constituents, and particle size are all key parameters considered by the boiler designer. Some biomass products have unique utilization issues. The chemical fraction behavior of biomass materials is quite different from that of typical coals. For co-firing applications, the properties of biomass and coal can be blended as a designer fuel. The objective is to best meet boiler, combustion, emission, and economic requirements. Fuel degradation and spontaneous combustion are more important concerns for biomass fuel products. This is a moisture-dependent issue. Dry biomass can be stored for longer periods. High moisture levels become a concern for degradation and spontaneous combustion. Therefore the paper deals with the biomass characterization in terms of its physico-chemical properties which can be useful to understand biomass combustion related issues.

134 - 142

Authors: S. H. Pishgar-Komleh, A. Keyhani, M.R. Mostofi-Sarkari, A. Jafari

Seed corn is one of the most important crops due to its high economical value. For this reason harvesting operation should be done precisely. Losses in harvesting seed corn are inevitable but can be decreased to the acceptable level. There are several machinery factors such as cylinder and travel speed which can affect total harvesting losses in two stage harvesting method (with picker-husker and sheller). For this purpose this study evaluated the amount of losses in different speed levels (3, 4 and 5 km h-1) and cylinder speed (400, 500 and 600 rpm) and investigated the relationship between the specified factors (independent variables) and machinery losses (dependent variable). All types of machinery losses were measured and summed as total losses from a representative seed corn field. In order to find the relationship between the variables several models (linear, 2FI, quadratic and cubic) were tested. All analyses were done by applying the response surface methodology based on two variables, three levels and central composite design (CCD). Based on the results of this study, the relationship between cylinder and travel speed was analyzed and the corresponding model was designed. The results recommended that the 2FI model as the highest order model with significant term can describe the harvesting losses in relationship between cylinder and travel speed. The coefficient of determination (R2), the adjusted determination coefficient (adjusted R2) and coefficient of variation (CV) were calculated as 0.90, 0.89 and 3.69%, respectively and the response surface results showed that an increase of travel and cylinder speed would lead to an increase of harvesting losses. It was denoted that the travel speed have more impact on harvesting losses in comparison with cylinder speed. The optimization study showed the least harvesting losses of 209.88 kg ha-1 in cylinder and travel speed of 600 rpm and 3 km h-1, respectively. It was concluded that the increase of travel and cylinder speed resulted in the increase of harvesting losses where the highest losses score was occurred in 5 km h-1 and 600 rpm, respectively.

157 - 161

Authors: S.N. Azizi

Hartree-Fock self-consistent-field (HF-SCF) theory and the Gauge-including atomic orbital (GIAO) methods are used in calculation of 27Al NMR chemical shifts for units of compounds of various aluminate species of precursors for zeolites. Calculations were performed at geometries optimized at AM1 semi-empirical method. The GIAO-HF-SCF calculations were carried out using three different basis sets: 6-31G*, 6-31+G** and 6-311+G(2d, p). The intensity of partially overlapping NMR peaks may be separated by deconvolution into individual Gaussian component peaks. The relative concentrations of aluminosilicate species present as q1, q2, q3 and q4 structural units, have been estimated from integrated intensities of the corresponding signals. It is pertinent to notice that the spectra in and the estimated data showed that the intensity of q4 (the band at lowest frequency), seems to increase as Si/Al mole ratio (at constant Si=0.875 and TMAOH=1 M) decreases, i.e. with increasing aluminates concentration. However, the bands become broader as the concentration of Al increases, so that operation of backward linear prediction (BLP) is of variable effect. From this study, one can expect that cage-like species might be dominant due to the stability of the corresponding silicate anions in TMAOH silicate solutions. The formation of three-member rings apparently causes some deshilding compared to chains or larger rings.

167 - 172

Authors: Tarig Osman Khider, Safaa Omer, Osman Taha, Suhair Kamal Shomeina

The fibre characteristics and chemical composition of Gossypium Hirsutum, Sudanese cotton stalks were assessed for their suitability for paper making. Soda-anthraquinone (soda-AQ), alkaline sulphite-anthraquinone (AS-AQ) and ASAM (alkaline sulphite-anthraquinone- methanol) cookings were carried out with different alkali charges and pulps with acceptable to good yields and mechanical properties were obtained. ASAM pulping gave the best results in yields, degree of delignification, mechanical pulp properties. AS-AQ pulping cooking with ratio (70: 30) as NaOH: Na2SO3 gave better results compared to (60: 40) ratio.

189 - 196

Authors: Ali Saberi

In this study, synthesized bimetallic Ni/Fe nanoparticles and zero-valent iron nanoparticles (nZVI) were investigated for remediation of Pb2+ against the effect of various parameters such as pH, volume to mass (V/m) ratio, contact time, initial concentration of Pb2+ on removal efficiency. Results of the present project suggest both Ni/Fe bimetallic nanoparticles and nZVI adsorbents have shown maximum removal of Pb2+ at pH 5 with an increasing trend with increasing pH. The V/m ratio optimization study reveals that the same volume of the lead solution requires more Ni/Fe bimetallic nanoparticles than nZVI. The time to achieve equilibrium is same in both the cases. Similarly, decrease in the removal efficiency with increase in initial concentration of Pb2+ is observed in both the cases.