(599c) Experimental Investigation of Combustion Characteristics of a Heating Furnace By Hydrogen/Air Micro-Jet Diffusion Flame

With the depletion of fossil fuel and strict pollution emission regulation in recent decades, the research on the elementary investigation and application of clean alternative fuels has drawn more and more attention [1]. Numerous candidates, such as biofuels, natural gas, ammonia, and hydrogen (H₂), have been proposed as alternative fuels. Among them, Hydrogen (H₂) is considered as one of the most promising candidate with following advantages: (a) H₂ is considered as CO_x and soot emission free when combusted [1]; (b) H₂ are produced from various sources, such as water electrolysis by renewable and nuclear energy [2], fuel reforming from hydrocarbon fuels [3], and gasification from coal and biomass [4]. These merits make H₂-based energy system as an attractive power source, which is important to the safety of the nation energy supply.

The effects H₂ addition on high intensity distributed combustion under swirling flow conditions has been investigated by Khalil and Gupta [5]. The results showed that CO and NO emission were substantially reduced when methane added with H₂. Extremely low emissions of CO (<9 ppm) and NO (<3 ppm) were obtained. Tang et al. comparatively studied the combustion characteristics of methane, propane, and hydrogen fuels in a micro-combustor [6]. They found that H₂/air flame exhibits a wide range of stable flames at various equivalence ratios. The temperature gradient of combustor wall is large because short H₂ micro-jet flames are formed near the inlet, which is different from that of methane and propane flames. The elementary combustion properties have been investigated to apply H₂ as a fuel.

Many researches on combustion characteristics of premixed/non-premixed H₂ added flame, H₂ addition on engine combustion, and fuel cell application have been focused. However, little work has been conducted on the development of H₂ designated burner for thermal application. Therefore, to supply thermal in industrial process, we aim to develop a H₂ designated burner to suit the high burning velocity and short flame length characteristics of H₂ flame. An array type micro-jet burner is proposed and produced in this research. A stainless micro-jet array burner for H₂ combustion is manufactured. The effects of H₂ input power and equivalence ratio on the flame structure, OH radical distribution and furnace temperature of H₂/air diffusion flame on a micro-jet array burner are experimentally investigated. The results show that furnace temperature increased with increasing input power because of intensive formation of OH radicals. The furnace temperature distribution decreased with increasing distance from outlet of the burner and air ratio.

Reference

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[6] Tang A, Xu Y, Shan C, Pan J, Liu Y. A comparative study on combustion characteristics of methane, propane and hydrogen fuels in a micro-combustor. Int J Hydrogen Energy 2015;40: 16587–16596.