The heat coming out from the oxidation of hydrocarbons which is identified by combustion is a major source of energy responsible for almost 98% of total energy worldwide. The prevalent types of the fuels used in the combustion for the production of energy were hydrocarbons which are being extracted from the shell of the earth.
The hydrocarbon fuels in the combustion produce a variety of the pollutants, including the greenhouse gases such (CO2) and noxious gases such as (NOXand CO, SOX). The cons of the use of hydrocarbons are now overshadowing their pros, making the human being to find a replacement for these energy producers which are clean, renewable and accessible everywhere. The renewable fuels such as alcohols and biodiesels were being considered as surrogate fuels for this purpose, especially since the energy crisis in the 1970s when the need for fuels are felt more than before.
Although the use of renewable fuels extracted from living species did not possess the main problems associated with the fossil fuels, they are not totally benign and infallible. The quality of the combustion with these fuels is to some extent inferior to their conventional counterparts (i.e., fossil fuel). Hence, the improving the combustion quality of renewable fuels should be taken into account of consideration to have clean fuels which are not only benign and pollution free but also provide combustion characteristics on par of fossil fuels.
To this end, pre, in situ, and post-combustion treatment strategies are being considered and used. Within these strategies, pre-combustion treatment has emerged as the most effective initiative as it does not only the have the advantages of both in situ and post-combustion treatment the but it also provides a degree of freedom for manipulating of the fuels in terms of properties other than those combustion dependent ones. The pre-combustion additives, for instance, could not only improve the combustion characteristics of biofuels, but also they may increase the cold properties (poor, and cloud points) of the fuels making them able to withstand the harsh environmental conditions and to efficiently being used in the cold seasons.
Conventionally the use of metal, oxygenated, depressants and wax Dispersants, ignition promoters, and vegetable oils were used as additives for the combustion treatment of the fuels. The additives used for the improvement in the combustion quality is called “Fuel Borne Catalyst” (FBC). Metallic FBC such as Fe, Mg, and Zn could form high valent radicals during the combustion, thereby forming suitable oxidation sites for the combustion of fuels. They act as smoke suppressants and cetane improvers. Some of the metals such as Wolfram could play the role of the reduction agents, precluding the formation of gaseous pollutants during the combustion. Combination of metals with these properties could improve the combustion quality, providing benefits in the operation of the combustion system.
According to the estimation of the worldwide trade organization in 2004, the transactions being conducted for fuels are responsible for about 11.1% share of total trades worldwide. Owing to this remarkable very important role of the fuels, the human beings are always trying to improve and optimize the use of the fuel. The results of our study demonstrate that the use of FBC leads to noticeable improvements in the combustion quality and also to the economization of the renewable fuels in the combustion systems. The economization can be achieved from two influences of the FBC on the combustion. First, FBC can improve the combustion and diminish the use of fuels in the combustion systems. Second, the FBC can limit the formation of pollutants, thereby reducing the external costs (i.e., an amount of money should be paid for damaging the environments).
The prospective researchers are to improve the combustion quality of the biofuels and to design novel additives to improve another aspect of biofuels. Qualities such as poor and cloud points, density, and a slightly higher viscosity of the biofuels are still problematic hindering the replacement of these fuels with conventional fuels. Our future prospects go towards the design catalysts that it is not only able to improve the combustion quality of the renewable fuels, but also to improve the properties of these fuels.
These findings are described in the article entitled Mixed modified Fe2O3-WO3 as new fuel borne catalyst (FBC) for biodiesel fuel, recently published in the journal Energy. This work was conducted by Bahamin Bazooyar, Seyyed Yaghoob Hosseini, Solat Moradi Ghoje Begloo, and Ahmad Shariati from the Petroleum University of Technology, and Seyed Hassan Hashemabadi and Fariborz Shaahmadi from the Iran University of Science and Technology.