Solvent technology – environmental issues (Task 2)

The task works to understand degrading of solvents better by investigating which factors has the highest impact on the stability of amines (organic compound derived from ammonia). Furthermore, the task will contribute to reduction of operational- and investment cost by indicating amines with higher stability and developing technologies to control and monitor solvent stability.

This task is primarily related to Deployment Case 1, and will provide important insight on solvent technology and its related environmental issues.

The research results will provide useful information on solvent behaviour for parties like:

  • Authorities
  • Technology- and solvent vendors
  • Carbon capture facilities

The task will work to understand degrading of solvents better by investigating which factors has the highest impact on the stability of amines (organic compound derived from ammonia). Furthermore, the task will contribute to reduction of operational- and investment cost by indicating amines with higher stability and developing technologies to control and monitor solvent stability.

This is important because solvent technology is widely used in industry and is the most mature technology for large scale CCS. Two full scale post combustion CO2 capture plants based on solvent technology are in operation in USA and Canada. Our research focuses on solvent management and is relevant for the Norwegian cases and any full-scale plants worldwide. Furthermore, the research results will also be important for actors in the power generation industry, oil and gas industries and aluminium and cement production.

The task is working closely with the following partners:

Main Results 2018

Main Results

  • Verification of experimental set-up for degradation tests and oxygen solubility.
  • Effect of amine concentration, loading and temperature on O2-solubility studied.
  • Guidelines/lessons learned for evaluating solvent stability presented
  • PLS model tested on real/aged MEA samples from bench scale experiments to large Pilot Plant.
  • Developed techniques for oxygen removal showed good results with removal rate above 80% obtained.
  • Test and scale up study of oxygen removal techniques performed

Impact and innovations

  • Observation from pilot plant operations in several capture plants shows that there is a correlation between the level of dissolved oxygen in the rich absorption liquid and the degradation profile. Reduction /removal of dissolved oxygen can significantly reduce solvent degradation and then reducing operational problems and cost of carbon capture plants using amine technology.
  • Reaction schemes for MEA or other amines are transferable to other amines. Data from pilots, especially, for MEA is currently available and could be used to verify different laboratory set-ups.
Figure illustrating 2018's main results: DORA LL MODE, Sodium Sulphite as scavanger

Results 2017

One of the drawbacks for post-combustion CO2 capture with solvent technology is that absorption capacity of a solvent is reduced because of for example degradation. This mean that unwanted chemical reactions (degradation) occur in addition to the CO2 absorption and desorption reaction.

Different strategies are used to reduce unwanted reactions:

  • Development of mitigation technologies to reduce degradation
  • Development of new experimental methodologies to predict chemicals stability of new solvents at process conditions
  • Gathering of knowledge on relation between amine structure and chemical stability. In addition, online monitoring of the solvent status in the process has been a focus

The main results from 2017:

  • Successful proof-of-principle of the oxygen removal concept (mitigation technology)
  • New methodology has been suggested for evaluation of chemical stability of solvents
  • Several amine structures sensitive to degradation have been identified
  • The existing Partial Least Square (PLS) model used to evaluate solvent status has been improved

Task leader