Jeffrey Tyska, Honeywell, highlights how advanced carbon capture technologies can help cement producers significantly reduce CO2 emissions and achieve their decarbonisation goals.
Decarbonising the cement industry is crucial to limiting global warming to 1.5°C, a target set by the United Nations. According to the GCCA 2050 Cement and Concrete Industry Roadmap, cement producers will have to fully decarbonise by 2050 to meet this goal. This decarbonisation will require major CO2 reductions. While improved efficiency and savings in cement clinker production will also help reduce emissions, perhaps the most promising method of reducing carbon emissions from cement plants is carbon capture. By 2050, over 1 Gt/year of CO2 will need to be captured by cement producers, which is a more than 400% increase from the 2030 goal of 258 million tpy. Honeywell UOP has a portfolio of carbon capture solutions that can help producers achieve these goals while also helping to minimise energy usage and cost of capture. These include solvent, adsorbent, and cryogenic CO2 capture solutions.
Advanced carbon capture technology
Traditional solvents such as MEA (monoethanolamine) have been used for over 80 years to capture acid gases such as CO2 in natural gas plants, however they face significant challenges in flue gas services due to large regeneration energy requirements, tall absorbers, and high rates of solvent degradation in the presence of oxygen. Honeywell UOP’s Advanced Solvent Carbon Capture technology (ASCC) was developed in collaboration with the University of Texas at Austin to help address these challenges and provide a cost-effective solution for carbon capture. ASCC uses a proprietary solvent in tandem with a high-pressure stripper and a novel heat exchange flow scheme to mitigate the effect of these challenges. The solvent enables a high mass transfer rate, leading to shorter and less expensive absorbers. The solvent also has high thermal stability, enabling high regeneration pressures of 4 – 6 bar(g). The high regeneration pressure significantly reduces the amount of electricity required to compress the captured CO2 to the desired product pressure for sequestration, while also lowering the CAPEX required for CO2 compression. Both the solvent and novel heat exchange scheme enable low regeneration energy requirements, typically from 2.1 – 2.4 GJ/MT CO2. While flue gas conditioning is generally required to manage contaminants such as NO2, the ASCC solvent is more resistant to oxidative degradation than many other solvents, leading to reduced makeup requirements and less reclaiming.
The ASCC solvent has been tested for over 8500 hours at the National Carbon Capture Center (NCCC) in Wilsonville, Alabama using flue gas CO2 concentrations of 4 – 12 vol% and a variety of contaminant concentrations, with higher concentration testing performed at University of Texas. The testing has included a skid specific to the unique heat exchange set up for ASCC, along with the high-pressure stripper setup. The unit has demonstrated low rates of solvent degradation and low energy consumption along with testing metallurgy, effects of contaminants, and emissions. The unit has demonstrated solvent emissions under 1 ppmv and produces CO2 with less than 1 ppmv of SOx and NOx content.
The ASCC solvent is also being tested at Technology Centre Mongstad (TCM) in Norway on residue fluid catalytic cracker (RFCC) and steam boiler flue gases, further demonstrating ASCC’s ability to efficiently capture CO2 from a variety of sources. ASCC has been selected for multiple Department of Energy (DOE) funded FEED studies, and Korean conglomerate SK E&S recently selected ASCC to help demonstrate CO2 capture viability at a natural gas power plant.
Electric carbon capture solution
While ASCC units often use steam to regenerate the solvent, they can also be configured to run using only electricity. This novel design reduces electricity usage in multiple ways. This includes utilising a heat pump that can efficiently recover heat from a variety of sources in the unit. The design and heat pump fluid allow for a high coefficient of performance (C.O.P.), lowering the unit’s overall energy requirements. Additional energy from the regenerator is recovered by utilising compression to further improve heat recovery in the unit. The energy performance of the e-ASCC is competitive and should be considered where project or site specifics make sense.
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