Energy Analysis of Baby Boiler for Steaming of Raw Cashew Nut Seeds

The steaming of raw cashew seeds prior to shelling is adopted widely in small-scale cashew nut processing mills with the help of baby boiler. The wide variations in energy intensity of these mills reveal the scope for energy conservation. The baby boiler coupled with cooker commonly used for steaming of raw seeds was evaluated. The variation in steam pressure, temperature and operating time with respect to fuel was observed along with thermal efficiency of a boiler. The energy intensity to produce the steam using different fuel sources determined. The study revealed that the thermal efficiency of boiler using electricity as a fuel was higher (69.31%) as compared to 4.66% (Wood) and 4.47% (Cashew nut shell). It was observed that, the energy consumed per kg of cashew nut steaming using electricity (248.99？kJ/kg) was minimum followed by wood (3829.96？kJ/kg) and cashew nut shell (3835.64？kJ/kg). The variation of energy consumption for cashew nut steaming revealed the scope for energy conservation in biomass combustion system. The improvement in the biomass combustion efficiency for steam generation could results in less fuel consumption and shorter period. 1. Introduction In the world scenario, India occupies a premier position contributing to about 43 per cent of the cashew nut (Anacardium occidentale L.) production [1]. Maharashtra has 164000？ha of area under cashew cultivation with average production of 1,97,000 tons of cashew nuts and attaining productivity of 1500？kg/ha [2]. India processed raw cashew nut seeds through 3650 cashew processing mills scattered in many states of country, which increased rapidly from 170 in 1959 to over 3650 in year 2008 providing employment to over 0.5 million people of which 95 percent are women. Maharashtra state has total 2200 cashew processing units out of which 1850 are small cottage mills mainly located in Konkan region (70°17′–74°31′E longitude and 15°37′–20°20′N latitude) of Maharashtra with 1, 31, 288？ha land area under cultivation producing 1, 92, 600 tons of raw cashew per annum [3]. Various processes involved in cashew nut processing are cleaning, drying, roasting or steaming, shelling and cutting, drying of kernels, peeling, grading, and packaging. Roasting method involves application of heat to the nut, which releases the nut shell liquid and makes the shell brittle which facilitates the extraction of the kernel when breaking the shell open [2]. The steaming of raw cashew seeds prior to shelling is adopted widely in small-scale cashew nut processing mills. The steaming of raw cashew seeds is carried out by