**5. Methodology**

**3. The torrefaction technology**

46 Gasification for Low-grade Feedstock

**4. Renewable biomass sources**

coconut petiole equal to 39 × 1012 kcal [20, 21].

needs [19].

Torrefaction is a recently well-known technology to upgrade biomass for combustion and gasification applications. It is a thermal pre-treatment technology carried out at atmospheric pressure in the absence of oxygen. Torrefaction of biomass can be described as a mild form of pyrolysis that occurs at temperatures between 200 and 300°C [4]. During torrefaction, the more easily combustible components of biomass (i.e. hemicelluloses) are decomposed first and most vigorously, through carbonization. Only minor decomposition of lignin and cellulose occur at torrefaction temperatures but rate of decomposition depends on the type of biomass [14]. Their chemical structure is changed but no significant mass losses occur [15, 16]. The solid uniform product that is produced has a very low moisture content, high heating value [17] and less hydrophilic compared to the untreated biomass to fresh biomass [1]. Furthermore, the fibrous and tenacious nature of the biomass is reduced, resulting in a brittle

Like any developing country, the Philippines is facing a formidable challenge of promoting sustainable energy options to support the energy requirements of its economic and social development goals with minimal adverse effects on the environment. The Philippines utilizes renewable energy sources including hydropower, geothermal and solar energy, wind power and biomass resources. In 2015, these sources contributed 20,963 GWh of electrical energy, out of which, 41% is hydropower while 53% is geothermal power. Solar energy, wind power and biomass energy application accounts for around 6% of the primary use in the country. These renewable energy sources represent 25.44% of the country's energy

Among the coconut farm wastes such as husks, shell, coir dust and coconut leaves, the latter is considered either the most grossly under-utilized or completely un-utilized, only to be utilized by in situ burning at the coconut farm in order to dispose. A study conducted by Banzon [20] considered only the petiole to assess the fuel potential of the coconut leaf. Banzon reported that 376.9 million trees each producing at least 12 leaves a year or a total of 45 × 108 leaves with a total weight of 4000 kcal/kg (16.7 MJ/kg) makes the energy available from the

*Imperata cylindrical*, or cogongrass grows all around the world, including the Philippines. In general, cogongrass is composed of three main components: **C**ellulose, hemicellulose, and lignin [22]. Cellulose and hemicellulose can be converted into fermentable sugars and produce a large amount of fuels and chemicals by fermentation and chemical processes [23]. *Imperata*

**4.1. Coconut leaf, cogongrass and rice husks as a renewable source of energy**

material that can easily be comminuted into smaller particles [18].
