Search

This work reports the results of the life cycle assessment (LCA) of two carbonation processes aimed at permanent CO2 storage, employing Basic Oxygen Furnace (BOF) slag from steel manufacturing as alkalinity source. Specifically, the performance of the slurry phase and wet carbonation routes were compared assuming to store the CO2 emitted from a 10 MW conventional natural gas power plant. The LCA was based on the material and energy requirements for each of the involved process steps, i.e. pre-treatment and transport of raw materials, CO2 compression, carbonation, post treatments and management of the obtained products. The slurry and wet route resulted in a net avoided greenhouse warming potential (GWP) of 473 and 384 kg CO2/MWhel, respectively. Nevertheless, both routes affected the other environmental impact categories. In general, the wet route had approximately two times higher impact than the slurry route, due in particular to the higher material and energy requirements. An exception was the abiotic resource depletion which resulted higher for the slurry route due to greater water requirement with respect to the wet route. The contributions to all mid-point impact categories were mainly due to energy requirements. A sensitivity analysis showed that the environmental impacts are affected by the energy mix and by the transport distance of slags and carbonation products., QC 20171020

The need for inventive techniques to address current soil- and water pollution problems has sparked research on remediation methods such as accelerated carbonation technology (ACT). However, the majority of research has focused on optimising the process by applying highly enhanced and energy-intensive conditions, thereby making large-scale application unfeasible. The HOMBRE project is working on integrated techniques to make redevelopment of polluted Brownfield areas faster, more profitable and more sustainable. In line with this, the current work investigated the feasibility of accelerated in-situ carbonation of industrial wastes under more ambient conditions with as objective to improve the materials environmental behaviour. Special focus was on stainless steel slags. The experimental research consisted of a full physical and chemical characterisation of the material with subsequent carbonation experiments. Initially, batch experiments were conducted to determine the maximal CO2-uptake of the material whereas in a later stage column carbonation was performed according to a new direct-carbonation set-up. Results indicated that performance of the column set-up was similar to more widely-used methods under similar conditions: a CO2-uptake of 5.5% was found for a reaction time of 8h in the column. Post-carbonation analysis pointed out that treatment indeed had significantly altered the slags mineralogy. The main effects of this were an increased buffering capacity, a reduced alkalinity, and significant changes in the leaching concentration of hazardous metals.

The need for inventive techniques to address current soil- and water pollution problems has sparked research on remediation methods such as accelerated carbonation technology (ACT). However, the majority of research has focused on optimising the process by applying highly enhanced and energy-intensive conditions, thereby making large-scale application unfeasible. The HOMBRE project is working on integrated techniques to make redevelopment of polluted Brownfield areas faster, more profitable and more sustainable. In line with this, the current work investigated the feasibility of accelerated in-situ carbonation of industrial wastes under more ambient conditions with as objective to improve the materials environmental behaviour. Special focus was on stainless steel slags. The experimental research consisted of a full physical and chemical characterisation of the material with subsequent carbonation experiments. Initially, batch experiments were conducted to determine the maximal CO2-uptake of the material whereas in a later stage column carbonation was performed according to a new direct-carbonation set-up. Results indicated that performance of the column set-up was similar to more widely-used methods under similar conditions: a CO2-uptake of 5.5% was found for a reaction time of 8h in the column. Post-carbonation analysis pointed out that treatment indeed had significantly altered the slags mineralogy. The main effects of this were an increased buffering capacity, a reduced alkalinity, and significant changes in the leaching concentration of hazardous metals.