Oxy-Fuel Combustion Characteristics of Pulverized Coal under O2/Recirculated Flue Gas Atmospheres

Shuhn-Shyurng Hou,Ta-Hui Lin,Chiao-Yu Chiang

doi:10.3390/app10041362

Shuhn-Shyurng Hou, Ta-Hui Lin + Show 1 more

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https://doi.org/10.3390/app10041362

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Abstract

Oxy-fuel combustion is an effective technology for carbon capture and storage (CCS). Oxy-combustion for coal-fired power stations is a promising technology by which to diminish CO2 emissions. Unfortunately, little attention has been paid to the oxy-combustion characteristics affected by the combustion atmosphere. This paper is aimed at investigating the oxy-fuel combustion characteristics of Australian coal in a 0.3 MWth furnace. In particular, the influences of various oxygen flow rates and recirculated flue gas (RFG) on heating performance and pollutant emissions are examined in O2/RFG environments. The results show that with increases in the secondary RFG flow rate, the temperatures in the radiative and convective sections decrease and increase, respectively. At a lower oxygen flow rate, burning Australian coal emits lower residual oxygen and NO concentrations. In the flue gas, a high CO2 concentration of up to 94.8% can be achieved. Compared to air combustion, NO emissions are dramatically reduced up to 74% for Australian coal under oxy-combustion. Note that the high CO2 concentrations in the flue gas under oxy-coal combustions suggest great potential for reducing CO2 emissions through carbon capture and storage.

Highlights

Electricity is a crucial part of most industries and livelihoods
Recirculated flue gas (RFG) on heating and pollutant emissions areoxygen examined inrates heating performance and pollutant emissions are examined in O2 /recirculated flue gas (RFG) environments
(1st RFG) flow rate (70 Nm3 /h) are fixed at a constant oxygen supply (41.5 Nm3 /h or 38.5 Nm3 /h), with an increase in the flow rate of secondary RFG (2nd RFG), the temperature in the radiative section decreases, while the flue gas temperature in the convective section increases, This is because a larger flow rate of 2nd RFG leads to a lower flame temperature, and a reduction in the radiative heat transfer [14,15]

Summary

Introduction

There has been rapid development of alternative energy, the major power supply is still mainly produced from combusting fossil fuels like coal and natural gas. Taking this into consideration for coal-fired power plants, it is necessary to develop novel technologies to mitigate their impact on the environment from pollutant emissions and to improve efficiency. An air separation unit is utilized to produce the oxygen required for oxy-fuel combustion. Using this method, fuel only combusts in an oxygen-diluted environment with recirculated flue gas (RFG), and CO2 and H2 O are mainly produced in the flue gas (FG). It is worth noting that oxy-fuel combustion can reduce the amount of flue gas treated, can produce high levels of CO2 , and is feasible for retrofitting current power plants

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