Investigation on desulfurization and ground granulated blast furnace slags reutilization for carbon dioxide sorption in a fluidized bed reactor

Abstract

Background

The atmospheric CO₂ concentration is significantly increasing due to the utilization of fossil fuel in various activities. Implementation of steel slag is considered as a promising strategy for carbon capture

Methods

In this study, the slags from desulfurization (De-S) and ground granulated blast furnace (GGBS) processes in the steel company waste were applied as the sorbent in CO₂ removal using a fluidized bed system. Various operating conditions were applied to determine the influence of operating parameters on sorbent performance. Moreover, examination on sorbent characteristic change and kinetics calculation were also carried out in this study.

Significant finding

Optimum operating temperature was reached by the application of 600 and 500 °C for De-S and GGBS slag, respectively. The higher CO₂ concentration and 5 % water vapor improved the sorbent utilization. However, excessive water vapor and low fluidized velocity decreased the performance of sorbent. De-S slag performed better on overall CO₂ capture process compared to GGBS slag. Therefore, upscaled study with 10 times greater size was further conducted with the 150–300 µm De-S slag for the CO₂ capture from oxy-fuel and air combustion. The higher CO₂ partial pressure in the flue gas of oxy-fuel combustion increased the capture process efficiency.