International Journal of Advances in Scientific Research and Engineering (ijasre) E-ISSN : 2454-8006 DOI: 10.31695/IJASRE.2020.33861 Volume 6, Issue 9 September - 2020 www.ijasre.net Page 14 Licensed Under Creative Commons Attribution CC BY-NC Review of Stoichiometric Technique for Better Performance of the Boiler Prosper Ndizihiwe 1 , Dr. Burnet Mkandawire 2 , Dr. Venant Kayibanda 3 1 University of Rwanda, College of Sciences and Technology, Rwanda 2 University of Malawi, Faculty of Engineering, Malawi 3 University of Rwanda, College of Sciences and Technology, Rwanda _______________________________________________________________________________________________________ ABSTRACT The combustion within the boiler burns fuel to create heat energy which then produces electrical power. The combustion of fuel is its reaction with oxygen available in the air. The amount of fuel that can be well burnt is limited by the quantity of oxygen. Once all the fuel is not burnt at all, some of it stays in the boiler and other quantity goes to the atmosphere. Most of the fuels used in the boiler are hydrocarbons which release hydrogen and carbon as residuals. It causes small efficiency and degradation of the air. It is needed to take the faction of air/fuel to the optimum value to reduce these problems. This paper provides different reviewed algorithms that control the combustion within the boiler and the role of environmental temperature. The author found that the separation of the oxygen from the air combined with the preheating both fuel and oxygen taking into account environmental temperature would provide better stoichiometric values, which improve the performance. Keywords: Boiler, Combustion, Air fuel ratio, Fuel, Oxygen Control. ____________________________________________________________________________________________ 1. INTRODUCTION Energy is indispensable for the development of people. One way to generate energy is the combustion of fossil fuel within the boiler, which also take a big percentage[1],[2]. Most of the fuels used in the boiler are hydrocarbons, its combustion process is also referred to as the oxidation equation since it requires having oxygen; however, the hydrocarbon is combined with other elements in the air [3]. General combustion equation of hydrocarbon is given by      (  )   →    (   ⁄ )      (1)  is Carbon,  is Hydrogen,  is Oxygen,  and  are constants[4]. This equation shows the complete combustion. In reality, this is not what happens because oxygen is found as air combined with other elements  of oxygen and  of nitrogen [5]. So the equation becomes      (  )(     )  →    (   ⁄ )       (  )  (2) [4]. This means for every mole of fuel to be burned require  moles of Oxygen and (  ) moles of Nitrogen, and (  ) moles of Nitrite is generated [4], [6]. The stoichiometric or air-fuel ratio (AFR) is the fraction of the air to fuel in the combustion process within the boiler and others for the thermal power plant to burn the fuel to produce heat energy which then transformed into kinetic energy[7]. In the case this ratio is small (when the air is insufficient), it results in incomplete combustion which is the cause of low efficiency and much exhaust gases.[8] In the cases of bigger ratio (too much air presence), there will be the formation of much nitrogen (  ) as indicated by Figure 1 and its composition such as nitrite oxide   as indicated by Figure 4 [9], which are losses and at the same time are accumulated within the burner then disable the next process while reducing the lifetime of the boiler [10].