In Egypt, the fossil fuel (e.g., oil, coal, natural gas) is a primary source of energy which can cause health problems and environmental damage. Moreover, the recent increasing the price of conventional fossil fuel, global warming, climate change are the primary reasons to find alternative, cheaper, reliable and renewable resource to fulfill energy demand and substitute fossil fuels when the reserves are exhausted. In parallel, the agricultural wastes cause different problems to rural areas in Egypt, which causes soil and air pollution problems. The highest quantities of wastes are producing from some crops such as sugarcane, rice, corn, wheat and cotton. These waste materials include bagasse (sugar cane bagasse), straw (rice straw), cobs (corn cobs), and peel (banana and orange peel). The quantity of agricultural waste in Egypt is between 22 and 26 million dry tons per year [1]. So that, the large quantity of wastes should not be burned or disposed but should be rather treated as raw material for other industries. Sugarcane is the one of the largest agricultural crops in Egypt and bagasse is a major byproduct of the sugar industry, over 16.2 million tons of sugarcane is produced from over 125000 hectares of land, with an average yield of 126 tons/hectare[2]. Generally, one ton of sugarcane produces around 112 kg of sugar, 310 kg of dry bagasse and 41 kg of molasses[2]. Bagasse is a lignocellulosic residue remained after collecting the valuable parts of crops, which consists of around 40–50% cellulose, 20–30% hemicellulose, 20 − 25% lignin and 1.53% ash [3].
Bagasse is used for different purposes in different sugar mills. It is used for steam and power generation in Nagaa Hammadi Sugar Mill in the manufacture of fiberboard in Deshna Sugar Mill and in pulp and paper manufacture in Kous Sugar. The bagasse used to produce steam and electricity as a source of fuel for boilers. The bagasse's burning efficiency is only 60%, and bagasse is usually supplemented by another fuel such as fuel oil to increase the efficiency of combustion, which produce emissions due to high sulfur in fuel oil. So that bagasse cane is be used as renewable source of energy for production biofuels through thermochemical conversion processes [4].
Pyrolysis is a thermochemical conversion process used to convert biomass and organic materials into biofuels namely bio-oil, biochar and non-condensable. It is defined as the thermal decomposition of biomass in a closed reactor in absence of oxygen. The pyrolysis products distribution depends on process parameters as well as the compositions of biomass. The most important parameters are the type of reactor, pyrolysis temperature, heating rate, biomass particle size, residence time and sweeping gas flow rate (N2)[5]. The product yield of the pyrolysis depends on the operating parameters, properties of biomass, type of the pyrolysis process. Controlling and optimizing these parameters is a very important in order to maximize bio-oil yields and optimal product distribution.
Pyrolysis of different types of biomass such as olive bagasse [6], hazelnut bagasse [7], grape bagasse [8], orange bagasse [9] and sugarcane bagasse [10–13] has been performed in different types of reactors such as batch, semi-batch and continuous reactor. In most of these literatures, the effects of different operating parameters on products yield have been investigated. A. K. Varma and P. Mondal.[11] investigated the influence of pyrolysis temperature, heating rate, particle size range and sweeping gas flow rate on product yields from sugarcane bagasse pyrolysis in a semi batch fixed-bed reactor. The temperature of pyrolysis and heating rate were varied in the range 350–650 oC and 10–50 oC/min respectively. The particle size was varied in the range < 0.25– 1.7 mm and nitrogen flow rate 50–200 cm3/min. The result shows that the maximum bio-oil yield was 45.23% was obtained at 500 oC, heating rate of 50 oC/min, particle size of 0.5–0.6 mm and nitrogen flow rate of 100 cm3/min.
In this research, sugarcane bagasse pyrolysis was performed in a semi-batch reactor. The effects of pyrolysis temperature, particle size range and nitrogen flow rate on the pyrolysis product yields are explored to determine the optimal pyrolysis parameters for maximum bio-oil production.