Earth day 2013, Atlanta USA Energetic Potential of Plant Biomass Michael Ioelovich1* 1
Designer Energy Ltd, 2, Bergman St., Rehovot 76100, Israel *
Corresponding author, E-mail:
[email protected]
Introduction Nowadays, fossil fuels are the main energy sources, which cover about 85% of the world's energy needs. In recent years, a considerable attention is given to alternative energy sources, in particular, to plant biomass, which in contrast to fossil fuels is continuously renewable in the nature. Actually, only small part of the biomass can be utilized. The share of biomass use gives about 10% of world energy consumption [3]. To produce the biofuels can be used wastes of forest, wood, textile, pulp and paper industry, agriculture and cities, as well as some species of plants. Total amount of such raw materials, which is accumulated only in USA, is about 1 billion tons annually. The plant biomass can be utilized directly as a solid fuel or after their conversion into various types of biofuels, such as charcoal, bioethanol or biodiesel. To select the most efficient way for utilization of plant materials for energy production, it is necessary to know the energetic potential of these materials. Therefore, the main purpose of this presentation was determination of the higher heating value (HHV) of various types of biomass in the comparison with the energetic capacity of biofuels made from these plant raw materials EXPERIMENTAL
Materials: Some biomass samples were used such as: waste of textile, sawdust of poplar, bagasse of sugar cane, fallen olives and olive pomace. Besides, samples of charcoal, vegetative oil, biodiesel and bioethanol also were investigated.
Example 1: The sawdust was pyrolysed at 300oC for 1 h into charcoal. Example 2: The waste of cotton textile was hydrolyzed by enzymes and hydrolyzate was fermented to obtain bioethanol. Example 3: The fallen olives were pressed and the olive oil was transesterified with methanol to obtain biodiesel
Method: HHV of the samples were determined in the bomb calorimeter “Parr 6400” at 25°C according to ASTM D240.
Results: Table 1. HHV of dry samples Biomass sample HHV, MJ/kg Waste of textile Sawdust of wood Bagasse Fallen olives Olive pomace Olive oil Biodiesel Bioethanol Charcoal
17.3 19.8 18.4 28.1 23.0 39.5 40.2 29.8 28.6
It is important to understand, which way of the biomass utilization might provide the greatest energy: a direct burning of the biomass or burning of the biofuel that was made from this biomass? To do this, it is advisable to analyze the some typical examples for production of heat energy
Table 2. Heat energy of initial biomass and biofuel* Example Qb, GJ Y, kg/t Qf, GJ 1 19.8 400 11.4 2 17.3 340 10.2 3 28.1 251 10.1 *Note: Q b, Q f is heat energy of 1t of initial biomass, and biofuel having mass yield Y kg from 1 t of the initial biomass
Conclusions The calorific value of the biofuels produced from the biomass samples was from 28.6 to 40.2 MJ/kg, i.e. it was higher than HHV of the initial biomass raw-materials Despite of this, the most efficient way of the energy production is the direct burning of the plant biomass, while the burning of such amount of the biofuel, which can be obtained from plant material, gives a much smaller energetic effect - yield of the energy of the biofuels was 36-59% only from the energetic potential of the initial biomass
