A technology review for regeneration of sulfur rich amine systems
- Authors: Garg, Bharti , Verheyen, Vincent , Pearson, Pauline , Feron, Paul , Cousins, Ashleigh
- Date: 2018
- Type: Text , Journal article , Review
- Relation: International Journal of Greenhouse Gas Control Vol. 75, no. (2018), p. 243-253
- Full Text: false
- Reviewed:
- Description: Reducing the capital cost of post combustion CO2 capture by eliminating flue gas desulfurisation (FGD) pre-treatment, requires management of the amines preferential SO2 absorption. Novel technologies such as CS-Cap restrict the impact of SO2 to only a small fraction of the amine inventory resulting in high sulfate burden amines. Traditional thermal reclamation of these spent absorbents has advantages regarding simplicity, but ranks poorly for industrial ecology around PCC. These amines require low energy regeneration technologies compatible with their physico-chemical properties that also maximise the potential for valorising by-products. This review summarises the sulfur chemistry and outlines several amine reclamation processes. It assesses the status of established and novel regeneration technologies for their applicability to high sulfur loaded amines. Should deep sulfur removal be required, a hybrid approach with initial bulk removal (as product) followed by a polishing step to further reduce sulfur is prospective. A preliminary estimation of the relative cost of using standard reclamation methods for treating Sulfur loaded CS-Cap absorbent revealed the cost would increase due to its higher sulfate burden despite comparable treatment volumes. Research gaps are identified which would enable better comparison between the costs of traditional FGD versus higher reclamation costs for combined capture technologies.
Regeneration of sulfate-rich postcombustion capture amines through reactive crystallisation
- Authors: Garg, Bharti , Pearson, Pauline , Cousins, Ashleigh , McKnight, Stafford , Verheyen, Vincent
- Date: 2020
- Type: Text , Journal article
- Relation: Asia-Pacific Journal of Chemical Engineering Vol. 15, no. 6 (2020), p.
- Full Text: false
- Reviewed:
- Description: Flue gas desulfurisation is a prerequisite for successful CO2 capture in coal-fired power stations utilising aqueous amine absorbents. For nations like Australia, where there is nonexistence of mandatory flue gas desulfurisation, this increases the cost for power plants retrofitting CO2 capture. The CSIRO's CS-Cap process, a potentially low cost method for combined CO2 and SO2 capture, provides an alternate sulfur management solution to such plants. The CS-Cap process, however, results in high sulfur-loaded amines that require continuous regeneration to retain cost benefits. Reactive crystallisation by KOH addition is shown to be successful in removing the bulk of the sulfate from aqueous amines without any additional heating or cooling requirements. Increasing initial sulfate loading by amine recycling initially improves sulfate removal efficiency, up to the postsaturation level where the systems ionic strength determines further sulfate solubility. Oxidative amine degradation had no significant effect on the precipitation efficiency or purity of K2SO4 crystals apart from their slight discoloration. The behaviour of the residual potassium in these regenerated aqueous amines needs further investigation as it could lead to unwanted precipitation inside the absorber column and other parts of the process. © 2020 Curtin University and John Wiley & Sons, Ltd.