Effect of Cu(NO3)2 and Cu(CH3COO)2 Activating Additives on Combustion Characteristics of Anthracite and Its Semi-Coke

Kirill Larionov,Yury Bauman,Ilya Mishakov,Alexander Gromov,Aleksey Vedyagin,Konstantin Slyusarskiy,Svyatoslav Tsibulskiy,Anton Tolokolnikov

doi:10.3390/en13225926

Abstract

The process of anthracite and its semi-coke combustion in the presence of 5 wt.% (in terms of dry salt) additives of copper salts Cu(NO3)2 and Cu(CH3COO)2 was studied. The activating additives were introduced by an incipient wetness procedure. The ignition and combustion parameters for coal samples were examined in the combustion chamber at the heating medium temperatures (Tg) of 600–800 °C. The composition of the gaseous combustion products was controlled using an on-line gas analyzer. The fuel modification with copper salts was found to reduce the ignition delay time on average, along with a drop in the minimum ignition temperature Tmin by 138–277 °C. With an increase in Tg temperature, a significant reduction in the ignition delay time for the anthracite and semi-coke samples (by a factor of 6.7) was observed. The maximum difference in the ignition delay time between the original and modified samples of anthracite (ΔTi = 5.5 s) and semi-coke (ΔTi = 5.4 s) was recorded at a Tg temperature of 600 °C in the case of Cu(CH3COO)2. The emergence of micro-explosions was detected at an early stage of combustion via high-speed video imaging for samples modified by copper acetate. According to the on-line gas analysis data, the addition of copper salts permits one to reduce the volume of CO formed by 40% on average, providing complete oxidation of the fuel to CO2. It was shown that the introduction of additives promoted the reduction in the NOx emissions during the combustion of the anthracite and semi-coke samples.

Highlights

Coal is considered as one of the main pollution sources worldwide [1]
The catalytic combustion process is a viable technology for the low reactivity fuels [4,5,7,8], like anthracite, which permits one to increase the effectiveness of the fuel conversion [4,9] and enhance the environmental characteristics of the corresponding equipment [1,10]
The results of determining the minimum temperature of ignition and the ignition delay time of fuels allow us to conclude that the Cu(CH3 COO)2 additive made the greatest contribution to the activation of the ignition process

Summary

Introduction

Coal is considered as one of the main pollution sources worldwide [1]. Despite this, its significant share in both the primary energy (more than 25%) and, especially, electricity generation (around 35%) [2]makes it impossible to avoid using coal technology in the upcoming decades. While the application of anthracite for power generation is characterized by higher pollutant emissions [3], its combustion has been thoroughly studied recently [4,5,6]. The catalytic combustion process is a viable technology for the low reactivity fuels [4,5,7,8], like anthracite, which permits one to increase the effectiveness of the fuel conversion [4,9] and enhance the environmental characteristics of the corresponding equipment [1,10]. Modification of the sample with salt was performed by an incipient wetness impregnation procedure. The modification of the sample with salt was performed by an incipient wetness impregnation procedure described elsewhere [27,28].

Methods

Results

Conclusion