Modeling of some pistachio drying characteristics in fix, semi fluid and fluid bed dryer

Modeling of pistachio (cv. Ohadi) drying kinetic was carried out in a thin layer dryer of fix, semi fluid and fluid bed. Initial moisture content of pistachio samples was about 50.3% (d.b.).  Three drying characteristics of effective diffusivity, energy of activation and specific energy consumption were computed and influences of drying parameters were investigated.  Air temperature levels of 45, 60, 75 and 90℃ and bed conditions of fix, semi fluid and fluid bed were applied in these experiments.  Six mathematical models were used to predict the moisture ratio of pistachio samples in thin layer drying. Results showed that the Two-term model had supremacy in prediction of pistachio drying behavior.  Effective moisture diffusivity of pistachio was calculated using Fick’s second law.  Maximum and minimum values of effective moisture diffusivity calculated between 8.60×10-9 m2/sand 1.98×10-9 m2/s, respectively.  The calculated values of energy of activation for pistachio samples were computed between 30.52 kJ/mol and 35.26 kJ/mol for temperature boundary of 45 to 90℃ and bed conditions of fix to fluid bed.  Specific consumption of energy in thin layer drying of pistachio varied between 0.531×106 and 1.447×106 kJ/kg. Increase in air temperature in each bed condition cause decrease inspecific consumption of energy.  These pistachio properties are necessary to design the dryer system and to adjust the dryer in the best point.Keywords: Two-term model, thin layer drying, pistachio, diffusivity, energy&nbsp

A Review of Hydrogen as a Fuel in Internal Combustion Engines

The demand for fossil fuels is increasing because of globalization and rising energy demands. As a result, many nations are exploring alternative energy sources, and hydrogen is an efficient and practical alternative fuel. In the transportation industry, the development of hydrogen-powered cars aims to maximize fuel efficiency and significantly reduce exhaust gas emission and concentration. The impact of using hydrogen as a supplementary fuel for spark ignition (SI) and compression ignition (CI) engines on engine performance and gas emissions was investigated in this study. By adding hydrogen as a fuel in internal combustion engines, the torque, power, and brake thermal efficiency of the engines decrease, while their brake-specific fuel consumption increase. This study suggests that using hydrogen will reduce the emissions of CO, UHC, CO2, and soot; however, NOx emission is expected to increase. Due to the reduction of environmental pollutants for most engines and the related environmental benefits, hydrogen fuel is a clean and sustainable energy source, and its use should be expanded

A Review of the Existing Potentials in Biodiesel Production in Iran

Petroleum fuel plays an important role in industry, transportation, agriculture and other related industries in Iran. Iran has about 9.5% of the world’s total oil reserves in 2020 and is ranked 4th in the world. The presence of sufficient conventional fossil fuels for internal combustion engines has caused environmental problems. If these Iranian fossil fuels were to run out right now, there is no suitable alternative that is just as effective. The need to research alternative fuels in Iran is therefore unavoidable. In this study, the potential and available resources of raw materials, including rapeseed oil, palm oil, fish oil, waste oil, algae, animal fat, olive oil and jatropha oil for biodiesel production in different regions of Iran, have been reviewed. Given the potentials and resources described in this study, it is hoped that the findings of this study will play an important role in biodiesel production in Iran in the future and stimulate more researchers to create biodiesel from existing sources. It is also expected that this study will increase the attention of the governmental and non-governmental organizations in Iran to the existing resources for biodiesel production and development of these resources and get rid of the existing problems of fossil fuels by investing in this field

The Influence of Diesel–Ethanol Fuel Blends on Performance Parameters and Exhaust Emissions: Experimental Investigation and Multi-Objective Optimization of a Diesel Engine

Compression combustion engines are a source of air pollutants such as HC and Co, but are still widely used throughout the world. The use of renewable fuels such as ethanol, which is a low-carbon fuel, can reduce the emission of these harmful gases from the engine. A fundamental analysis is proposed in this research to experimentally examine the emission characteristics of diesel–ethanol fuel blends. Furthermore, a multi-objective genetic algorithm (e-MOGA) was developed based on the experimental data obtained to fine the most effective or Pareto set of engine emission and performance optimization solutions. So, the optimization problem had two inputs and seven objectives. For this purpose, input variables for the search space were S (rpm) varied in the range of (1600–2000) and E (%) varied in the range of (0–12). These design variables were chosen to be varied in a prespecified range with a lower and upper band as same as experimental conditions. A diesel engine using (DE2, DE4, DE6, DE8, DE10, and DE12) diesel–ethanol fuel blends, at the various speed of 1600 to 2000 rpm, was utilized for the experiment. The findings showed that the use of diesel–ethanol fuel blends decreased the concentration of CO and HC emissions by 3.2–30.6% and 7.01–16.25%, respectively, due to the high oxygen content of ethanol. As opposed to CO and HC emissions, the NOx concentration showed an increase of 7.5–19.6%. This increase was attributed to the high combustion quality in the combustion chamber, which resulted in a higher combustion chamber temperature. The optimization results confirmed that the shape of the Pareto front obtained from multi-objective ϵ-Pareto optimization could be convex, concave, or a combination of both. A new parameter was introduced as emission index or EI for selection of the best solution among the Pareto set of solutions. This parameter had a minimum value of 4.61. The variables levels for this optimum solution were as follows: engine speed = 1977 rpm, ethanol blend ratio = 10%, CO = 0.27%, CO2 = 6.81%, HC = 3 ppm, NOx = 1573 ppm, SFC = 239 g/kW·h, P = 56 kW, and T = 269.9 N·m. The EI index had a maximum value of 8.26. Conclusively, we can say that the optimization algorithm was successful in minimizing emission index for all ethanol blend ratios, especially at higher engine speeds

Experimental investigation of the tractor engine performance using diesohol fuel

Diesohol fuel is a mixture of diesel and bioethanol fuels in which the ratio of bioethanol is less than 15%. In this research work, performance of a tractor engine (Massey Ferguson 399) using diesohol fuel was investigated. In these circumstances, the concentration of UHC and CO2 emissions in the exhaust pipe were measured and analyzed. The engine was run at several speeds (1600-2000 rpm). The obtained results reveal that, when using diesohol fuels, the power and torque of the MF-399 tractor engine are increased by 3.17-8.50% and 1.75-10.28% respectively when compared to diesel fuel. This is due to a relatively more complete combustion of ethanol because of its high oxygen content. The fuel consumption and specific fuel consumption are also increased by 7.32-15.81% and 4.37-7.44% respectively due to low calorific value of ethanol compared to diesel fuel. The analysis showed that when diesohol is used, the rate of UHC is decreased but CO2 emission is increased. In brief, by using diesohol fuels, especially E6 blend in comparison to diesel fuel, engine performance and emissions are improved without any changes in engine structure for diesohol application