Hybrid CO2 Capture Research Articles

Techno-economic analysis of hybrid liquefaction and low-temperature adsorption carbon capture based on waste heat utilization

The techno-economic analysis of CO2 capture is important to determine its economic feasibility and its application to hybrid CO2 capture systems urgently needs more attention. This research conducts a techno-economic analysis of a hybrid CO2 system in which the waste energy and uncaptured CO2 from liquefaction are supplied to low-temperature adsorption to enhance the overall energy efficiency. Here, the process and energy models are coupled with the cost analysis model to estimate the capital cost, operational cost, and levelized cost of CO2 capture (LCOC) of the hybrid system. A series of parametric analyses are conducted to determine how the hybrid system's LCOC can be minimized. Results indicate the heat pump has the highest capital cost and is 4 times the compressor because it needs to satisfy the large cooling energy requirement. Moreover, the adsorbent mass exhibits a trade-off between a higher CO2 recovery rate and lower LCOC value due to increasing costs. Ultimately, based on 12.5 % CO2 partial pressure 1 kg/s flue gas, a liquefaction temperature of −48.15 °C, a desorption temperature of 92.5 °C, and operating pressure of 6 MPa, a comparable LCOC of 106.19 $ per tonne CO2 is yielded by the hybrid system.

Development of opposing surface wettability PVDF membrane to improve CO2 capture in membrane gas absorption

Membrane gas absorption (MGA) is a hybrid CO2 capture technology. However, the membrane wetting problem and the low CO2 permeability membrane constraint the MGA performance. Therefore, the development of PVDF membrane with opposing surface wettability is significant to increase the CO2 absorption performance. In this work, superhydrophobic membrane was first synthesised by templated method. The patterned surface of the membrane (tPVDF) demonstrated water contact angle (WCA) 152° and sliding angle (SA) 8.6°. Then, the opposite surface of the patterned surface was modified with ethylenediamine (tPVDF/EDA) and polydopamine (tPVDF/PDA). From the FTIR analysis, tPVDF/EDA and tPVDF/PDA have successfully deposited with amine and hydroxyl functional groups. By comparing with tPVDF, tPVDF/EDA and tPVDF/PDA showed smaller membrane average pore size of 0.29um and 0.25um respectively. However, the surface porosity of the membranes is almost unchanged at 50 % (tPVDF), 48 % (tPVDF/EDA) and 47 % (tPVDF/PDA). In the MGA performance, tPVDF/EDA and tPVDF/PDA improved CO2 absorption flux to 0.088 and 0.090 mol/m2s respectively from 0.005 mol/m2s. The results indicates that the improvement of MGA performance was mainly due to the NH2 and OH functional groups deposited on the membrane surface that enhanced the membrane affinity to polar CO2 and the superhydrophobic patterned surface inhibited the intrusion of absorbent into membrane pores. The CO2 absorption flux obtained in the work is reasonably good and comparable to the literatures.

Techno-Economic Assessment of Hybrid Co2 Capture Processes in Cement Manufacturing Based on Partial Oxyfuel & Post-Combustion Technologies

Techno-Economic Assessment of Hybrid Co2 Capture Processes in Cement Manufacturing Based on Partial Oxyfuel & Post-Combustion Technologies

Research Activities of CO2 Capture and Utilization Technologies at the Wyoming Integrated Test Center

The State of Wyoming along with private partners has constructed a post combustion carbon dioxide (CO2) capture and utilization test center, the Wyoming Integrated Test Center (ITC) for the testing of post-combustion CO2 separation and utilization technologies at a coal-fired electric generation power plant located at Basin Electric Power Cooperative’s Dry Fork Station (DFS). The plant is located seven miles north of Gillette, Wyoming. Additional project partners include Tri-State G&T, National Rural Electric Cooperative Association, Black Hills Energy, and Rocky Mountain Power. The ITC provides space for researchers to test CO2 capture, utilization (CCU) technologies using a combined 26 MWe of actual coal based flue gas. The 26 MWe equivalent of flue gas is split among one large test center and six smaller test bays. During commissioning of the flue gas delivery system, 23.5 MWe was determined to be available for the large test center while 2.5 MWe was available for distribution to the 6 smaller test bays. The flue-gas slip-stream is taken downstream of the state-of-the-art emissions control systems which substantially reduce criteria pollutants such as SO2, NOX, and Hg. Flue gas is supplied to the test bays with the following composition for the coal derived flue gas: Component Minimum Maximum Average CO2 12% 13.1% 12.7% O2 1.7% 4.2% 2.5% N2 + Ar 66.7% 66.7% 66.7% H2O 15.2% 18.3% 18.1% SO2 0.0 ppm 114.9 ppm 23.1 ppm NOx 19.2 ppm 38.4 ppm 27.8 ppm Temperature (1) 80 C 90 C 85 C The ITC’s first tenant deployed in 2019, and is a hybrid CO2 capture system designed by TDA Research. Using a membrane supplied by Membrane Technology and Research, the TDA system uses a combination of membrane and proprietary sorbent developed by TDA Research to capture 90% of the CO2 from the flue gas with a lower energy penalty than conventional amine based systems. TDA’s system will be followed up by a novel system developed by Kawasaki Heavy Industries that uses a solid sorbent combined with temperature and pressure swing to regenerate the material using waste heat. This project is advancing into the detailed design phase to determine precise footprint and utility interconnect requirements at the Wyoming ITC. In addition, in Q1 of 2020, teams competing for the NRG COSIA Carbon XPRIZE will begin to deploy. The XPRIZE is a $20 million global competition to develop breakthrough technologies that will convert CO2 emissions from power plants and industrial facilities into valuable products like building materials, alternative fuels, and other commercial products. Carbon Upcycling UCLA is in the process of finalizing HAZOP analyses and permitting, and will move to site in February or March 2020 to deploy their system capable of using CO2 from flue gas to cure precast concrete pieces. They will soon be followed by Dimensional Energy which has obtained an operating permit to photo-catalytically convert CO2 to CO for making synthesis gas. Additional contestants include C4X which plans to make polymers and insulation materials, Breathe which will manufacture methanol, and Carbon Capture Machine which has a process to produce precipitated calcium carbonate. Additional research activity continues with the subdivision of the large test center into two bays to accommodate two additional large pilot CO2 capture systems of approximately 200 tons per day each. One system utilizes technology developed at the University of Kentucky Center for Applied Energy Research and will utilize amine based solvents with advanced heat integration. The other system will be a membrane system provided by Membrane Technology and Research. Both projects are currently funded through a phase 2 contract through the National Energy Technology Laboratory and US Department of Energy. Dry Fork Station and the ITC have completed a relative accuracy test audit to verify a sufficient supply of flue gas for both projects. Additionally, utility requirements have been determined to be within the scope and capability of the ITC to provide the necessary power, water, and space requirements to accommodate both systems. Finally, a memorandum of understanding between the Japanese Coal Association (JCOAL), Columbia University, and GreenOre LLC to pursue research in CO2 utilization at the Wyoming ITC. The goal would be to produce a range of products from coal derived fly ash as well as investigate the possibility of concentrating rare earth elements in the residual ash. This paper provides a comprehensive update of the research activities at the Wyoming ITC which has been selected to host nine different technology providers from five different countries at scales ranging from 10 MWe.

Dual Carbon Dioxide Capture to Achieve Highly Efficient Ultra-Low Blood Flow Extracorporeal Carbon Dioxide Removal.

Extracorporeal CO2 removal is a highly promising support therapy for patients with hypercapnic respiratory failure but whose clinical implementation and patient benefit is hampered by high cost and highly specialized expertise required for safe use. Current approaches target removal of the gaseous CO2 dissolved in blood which limits their ease of clinical use as high blood flow rates are required to achieve physiologically significant CO2 clearance. Here, a novel hybrid approach in which a zero-bicarbonate dialysis is used to target removal of bicarbonate ion coupled to a gas exchange device to clear dissolved CO2, achieves highly efficiently total CO2 capture while maintaining systemic acid-base balance. In a porcine model of acute hypercapnic respiratory failure, a CO2-reduction of 61.4 ± 14.4mL/min was achieved at a blood flow rate of 248mL/minusing pediatric-scale primingvolumes. The dialyzer accounted for 81% of total CO2 capture with an efficiency of 33% with a minimal pH change across the entire circuit. This study demonstrates the feasibility of a novel hybrid CO2 capture approach capable of achieving physiologically significant CO2 removal at ultralow blood flow rates with low priming volumes while leveraging widely available dialysis platforms to enable clinical adoption.

CO2/N2 separation performance of Pebax/MIL-101 and Pebax /NH2-MIL-101 mixed matrix membranes and intensification via sub-ambient operation

Membrane-cryogenic hybrid process has been considered as a potential alternative for standalone CO2 separation. In hybrid process, CO2 from flue gas could be initially concentrated via membrane, and then high concentration CO2 stream is cryogenic-separated via phase change in low energy consumption. However, the sub-ambient separation performance and mechanism of membrane has been less investigated. In this work, Pebax 1657/MIL-101 and Pebax 1657/NH2-MIL-101 mixed matrix membranes have been fabricated and tested at sub-ambient condition. SEM, FITR and XRD results indicated that –NH2 has been successfully grafted to MIL101. Experimental results indicated that operating Pebax/MIL-101 and Pebax/NH2-MIL-101 at sub-ambient temperature (−20 °C) could enhance CO2 selectivity to 89.4 and 95.6, which increased by 96.5% and 145.1% compared with that at ambient condition. It indicated that Pebax 1657/NH2-MIL-101 has the potential to be used as sub-ambient membrane in membrane-cryogenic hybrid CO2 capture processes.

A novel concept of bicarbonate-carbon utilization via an absorption-microalgae hybrid process assisted with nutrient recycling from soybean wastewater

Abstract A novel ammonia absorption-microalgae hybrid CO2 capture and conversion process was investigated in this study. Using rich ammonia solution (ammonium bicarbonate) as a nutrient source for microalgae cultivation, the challenge of energy-intensive regeneration may potentially be overcome. To provide other nutrients for microalgae apart from ammonium bicarbonate, soybean wastewater was used to replace BG-11 medium for resource recycling and could adjust the pH of cultivation solution to reduce the threat of NH3 escape and inhibition. Chlorella sp. L166 and L38 were cultivated in ammonium bicarbonate solution using 5-times and 10-times diluted soybean wastewater under two culture modes (direct and batch feeding). The experimental results indicated that microalgae growth could be promoted by using 5-times diluted soybean wastewater as a cultivation medium with a removal rate of 50–65% COD, 70–80% NH3-N and 95–100% TP from a wastewater purification perspective. In the hybrid system, the NH3 escape ratio decreased to 15.8% with a carbon conversion efficiency of over 60%, and effectively achieved carbon and nitrogen utilization with 78.8 mg/L/d of microalgae biomass.

Integration of CO2 absorption with biological transformation via using rich ammonia solution as a nutrient source for microalgae cultivation

Energy penalty of solvent regeneration in CO2 absorption process is a critical challenge. To avoid the energy consumption, novel ammonia absorption-microalgae hybrid CO2 capture process has been designed in this work. In the proposed process, the conventional desorption column is replaced by a microalgae cultivation system. As a result, the NH4HCO3 could be utilized as nutrient for microalgae growth and converted into biofuel or value-added ingredients. Meanwhile, the challenge of ammonia escape could be avoided via high purity ammonia recycling in the hybrid process. The experimental results indicated that the selected Chlorella sp. L166, L38 and UTEX1602 could be potential microalgae to be used in chemical-biological hybrid CO2 capture and utilization process with carbon fixation efficiency over 85%, and the yield of protein, lipid and polysaccharides was 164 ± 1 mg/L (L166), 710.6 ± 165.8 mg/L (UTEX1602) and 143.6 ± 28.8 mg/L (L38), respectively. The above results also indicated that the novel absorption-microalgae hybrid process could be a promising alternative to the conventional CO2 absorption technology.

Intensification of a novel absorption-microalgae hybrid CO2 utilization process via fed-batch mode optimization

Ammonia-absorption-microalgae hybrid CO2 capture process presented the potential advantages in cost-effective CO2 capture and bioconversion. However, cultivation mode still needs to be intensified to reduce the negative influence of NH3 escape and its inhibition on microalgae growth. In the current work, three batch feeding modes of ammonium (i.e. NH4HCO3) for two Chlorella sp. (UTEX1602 and L38) were investigated. The experimental results indicated that initial NH4HCO3 deficiency (mode A) was beneficial for microalgae growth compared to the cultivation modes of uniform feeding (mode B) and decreasing dosage (mode C). Chlorella L38 presented a higher growth rate than UTEX1602, and might be more suitable for absorption-microalgae hybrid CO2 capture system. In detail, carbon utilization efficiency could achieve up to 76.8% in the absorption-microalgae hybrid process, which was two to three times higher than the conventional microalgae CO2 fixation processes. NH3 escape rate in absorption-microalgae hybrid process could be reduced to 24.2%, which was 18.8% lower than the conventional ammonia CO2 absorption process. Moreover, nitrogen and carbon in NH4HCO3 could be converted into biomass and value-added ingredients to realize resource recycling.

Intensification of CO2 separation performance via cryogenic and membrane hybrid process — Comparison of polyimide and polysulfone hollow fiber membrane

Cryogenic-membrane hybrid CO2 capture process has been considered as a promising alternative for the standalone processes to mitigate the critical challenge of energy penalty. In this work, two different commercial hollow fiber membranes were tested at low temperature condition to find the possibility of consisting a novel cold-membrane-cryogenic hybrid process. The gas permeation properties of membranes were evaluated at different operating temperature, CO2 concentration and stage cut. The experimental results indicated that cryogenic condition could facilitate to improve the CO2/N2 selectivity with a minimum permeance reduction. Specifically, with the operating temperature dropped to −20 °C and feed pressure set at 0.7 MPa, the CO2 selectivity of polyimide membrane increased by 166% with the permeance declined by 31%. Meanwhile, the CO2 recovery and purity of polyimide membrane achieved 92% and 49% at the temperature of −20 °C and pressure 0.7 MPa, respectively. It can be observed that operating membrane at cold condition could be a promising approach to intensify the CO2 separation, and thus decrease the energy consumption of subsequent CO2 liquefaction or desublimation in the hybrid process.

Techno-economic analysis of a hybrid CO2 capture system for natural gas combined cycles with selective exhaust gas recirculation

This work analyses the implementation of CO2 capture in natural gas combined cycle (NGCC) power plants using a hybrid system integrated by an amine scrubbing plant and a CO2 selective membrane. In this configuration, the membrane unit operates at close to atmospheric pressure and it is used to selectively recycle CO2 back to the inlet of the compressor, therefore increasing the CO2 content of the flue gas entering the capture system. A novel integration between the amine capture plant and the selective membrane is analysed here, which aims at exploiting the benefits of both the parallel and series selective exhaust gas recirculation (S-EGR) existing options. The mass and energy balances performed on this system indicate that the new configuration generates a flue gas with a CO2-enhanced concentration of 18%vol., which leads to a decrease in the energy demand in the reboiler by 6% with respect to an amine scrubbing system coupled to a conventional NGCC plant without S-EGR. Moreover, a reduction of 77% is achieved in the gas flowrate fed to the absorber of the amine plant, thus significantly reducing its size and cost. The calculated net electrical efficiency of the plant is 50.3%, which is 0.5 net percentage points higher than that of a conventional NGCC with amine-based capture and slightly lower than that of a reference plant with exhaust gas recirculation (EGR). These values are dependent on the pressure drop associated with the membrane system, which has a large influence on the energy balance of the plant. Therefore, higher efficiency improvements can be achieved if membrane module designs with reduced pressure drop are used. A techno-economic evaluation reveals that the cost of the membrane system has a strong effect on the capital costs of the plant and thus, on the cost of electricity and the cost of CO2 avoided. These values vary between $81.9 and $93.9 per MWh and $82.6 and $121.8 per tonne of CO2 avoided, respectively, for the S-EGR cases studied at a reference capacity factor of 0.85. A sensitivity analysis shows that it is necessary to reduce the costs of the reference hybrid S-EGR system in order to make it competitive against current benchmark options. Therefore, further ongoing development towards membrane units with high CO2 permeance, limited pressure drop and reduced costs is particularly interesting for the S-EGR system studied in this work. The obtained results also indicate the targeted values of these parameters that can make the cost of the S-EGR configuration to be below that of conventional systems with amine capture and EGR options for CO2 capture in NGCC power plants under different scenarios.

Reducing the energy consumption of membrane-cryogenic hybrid CO2 capture by process optimization

CO2 capture, utilization and storage (CCUS) is a significant strategy to mitigate climate change. Various capture technologies have been investigated in the last decades, such as absorption, adsorption, membrane and cryogenic, etc. However, energy penalty is considered as the major challenge for the existing techniques. One of the potential alternatives to overcome this challenge is the integration of different CO2 capture approaches. In the work, a novel low temperature-membrane-cryogenic CO2 capture process was proposed. Compared to the conventional membrane-cryogenic hybrid process, membrane performance is improved under sub-ambient condition. Meanwhile, the cold energy of liquefied natural gas is used to maintain low temperature and cryogenic condition. In detail, single factor optimization of various parameters (i.e. CO2/N2 selectivity, membrane area, CO2 concentration and feed pressure) on CO2 capture performance (i.e. CO2 purity, CO2 recovery and energy consumption) was investigated. The techno-economic feasibility of the proposed process was also studied and compared with the typical three-stage membrane process and membrane-cryogenic process. The simulation results indicated that the low temperature-membrane-cryogenic hybrid process consumed 1.7 MJ/kg CO2, which showed potential of energy saving compared with the conventional three-stage membrane and membrane-cryogenic CO2 capture processes.

CO2 Capture by Cold Membrane Operation

Air Liquide is developing a cost effective hybrid CO2 capture process based on sub-ambient temperature operation of a hollow fiber membrane in combination with cryogenic separation. These membranes, when operated at temperatures below -20˚C, show two to four times increase in CO2/N2 selectivity with minimal CO2 permeance loss compared to ambient temperature values. Long term (6 month) bench-scale testing with CO2/N2 mixtures at sub-ambient conditions has verified the enhanced separation performance seen at lab scale translated to commercial membrane modules [1,2].A relatively high CO2 capture rate is required to drive down the cost per tonne of captured CO2 as it valorizes the cost of the flue gas pre-treatment and compression prior to the membrane unit. However, as the CO2 recovery increases, the productivity of the membrane module decreases, thereby driving up the membrane system capital cost. The main reason for this is a “pinch effect”: the CO2 driving partial pressure differential across the membrane decreases as CO2 recovery proceeds. Computational fluid dynamics modelling shows that this effect can be partially off-set by a sweep operation where a small fraction (<5%) of the N2- enriched retentate gas is fed into the permeate chamber. Experimental measurements were made with a commercial 12” membrane module, as a function of CO2 recovery, in both sweep and non-sweep (baseline) mode. At the desired 90% CO2 recovery level, sweep operation resulted in 30% higher membrane productivity with negligible effect on permeate purity. This would result in 30% lower membrane system cost with negligible change in specific energy for CO2 capture.Bench-scale process optimization work with synthetic CO2/N2 mixtures is currently being performed within Air Liquide's Delaware Research & Technology Center, USA; this will be followed by field testing at the National Carbon Capture Center (Wilsonville, Alabama, USA) with pre-treated flue gas from air-fired coal combustion.

Accelerated MEA Degradation Study in Hybrid CO2 Capture Systems

CO2 capture systems are typically divided into pre- post- and oxyfuel- combustion systems. However, the interest on hybrid systems, which integrate elements of more than one of the above systems, is attracting major attention in recent times due to the potential higher energy efficiency. In this work, degradation studies have been conducted to identify operational issues related to amines degradation. Oxidative MEA degradation in presence of flue gas resembling oxygen enriched combustion has been investigated. MEA loss was 27% when flue gas with 15% CO2 was used at 70 °C, while only 20% loss was found in the presence of 50% CO2, indicating that hybrid CO2 capture systems may be used to decrease amine degradation of traditional post- combustion technologies. N-(2-hydroxyethyl)piperazin-3-one, N-(2-hydroxyethyl)-2-(2-hydroxyethylamino) acetamide, 2- oxadolidone, N-(2-hydroxyethyl)imidazole and N-N’-bis(2-hydroxyethyl)oxamine have been identified as MEA degradation products.

CO2 capture by sub-ambient membrane operation

Air Liquide is developing a cost effective hybrid CO2 capture process based on sub-ambient temperature operation of a hollow fiber membrane in combination with cryogenic distillation. Operation of these commercial Air Liquide membranes at low temperatures provides an unprecedented combination of CO2 permeability and selectivity. Both high membrane module productivity and high selectivity are critical for cost-efficient CO2 capture. High selectivity reduces the energy cost of CO2 capture while high module productivity reduces the capital cost of the membrane system. The proposed hybrid CO2 capture process concept couples the unique high performance membrane with cryogenic processing technology to efficiently capture at least 90% of the CO2 in the flue gas from an air fired power plant.This paper describes a successful long-term (8 month) test of the enhanced CO2 separation capability of the Air Liquide membrane at low temperatures. This demonstration was carried out with commercial scale membrane modules using a synthetic CO2/N2 feed and is an important milestone in development of the cold membrane process. The membrane selectivity and permeance validated through bench scale testing was fed into with process simulation studies coupled with process equipment cost estimates. These results indicate that the cold membrane process concept is promising for CO2 removal from flue gas generated by coal power plants.