The high temperature air combustion (HiTAC) is an advanced promising technology for heat recovery, energy saving, and stability improvement of flame. Computational fluid dynamic (CFD) is known as an applied tool to execute HiTAC modeling. In this paper, performances of pulverized coal combustion under the high preheated and oxygen deficient air are studied by both experimental and numerical methodology. The experimental facilities have been accomplished in a HiTAC chamber with coal injection velocity that ranges from 10 to 40?m/s. In order to achieve different preheated temperatures, the combustion air in such system is diluted by variable steam percentages from 0 to 44%. Results of mathematical simulation and experimental tests present convincible agreement through whole region. It is concluded that emission is reduced by increasing the steam percentage in the oxidizer due to decreasing the flame temperature. Besides, graphical contours show that by adding more steam to oxidizer composition, the oxygen concentration decreased. Additionally, results show that when the injection speed of fuel is increased, emission is also increased, and when the injection rate of preheated air is increased, emission shows decreasing trend. Further contribution in future is needed to investigate the performance of such technologies. 1. Introduction During the past decades, Coal has been primarily fueled for electric power generation because of cheap price and plenty of accessible mineral sources. After critical shortage of oil and natural gas for industrial benefits, a world wide effort is being made by scientists to develop methods for gasifying coals. Coal contains more or less properties similar to oil, so by a little modification of previous facilities, scientists can attain truthful equipment for solid state fuel instead of liquid/gas one. Once these methods are entirely developed, they will denote major source of coal utilization. The usage of gasified coal in power plant facilities will improve the combustion rate which leads a convincible clean combustion technology. Furthermore, gasified coal produces more efficient syngas that is functional for other purposes such as secondary combustion and sustainable heat recoveries. Generally, HiTAC is a prominent technique which compromises a possible solution to pollutant emissions reduction and heat transfer uniformity [1–4]. At first, HiTAC technology is developed in Japan in a great teamwork with several researchers in all over the world. The basic feature of this technique is that highly diluted and preheated air is
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