Cryogenic Carbon Capture Research Articles

Performance enhancement using multiple cryogenic desublimation based pipeline network during dehydration and carbon capture from natural gas

Cryogenic carbon capture from natural gas at high pressures requires accurate process synthesis and determination of process parameters due to the presence of solid–vapor and vapor–liquid–solid equilibria. At high pressures, the higher liquid formation not only causes operational problems, but also induces hydrocarbon losses in cryogenic packed beds. The present study proposes a novel multiple cryogenic desublimation based pipeline network with its sections at different cryogenic pressures and temperature profiles to enhance the separation. The experimental study explores the simultaneous separation of water and carbon dioxide from ternary feed gas mixture (CH4–CO2–H2O) by using multiple counter current cryogenic desublimation beds.A novel simulation strategy using multiple equilibrium temperature (MET) concept is also introduced for simulation studies. Simulation studies were subsequently conducted for both atmospheric and high cryogenic bed pressures and compared with experimental measurements. The effect of ambient humidity on dehydration was also investigated experimentally and it was observed that the humidity has significant effects on dehydration due to back diffusion. The effect of some important parameters like bed length, feed gas pressures, bed temperatures, feed flow rates and feed gas pressures for separation were investigated. Experimental investigation was also conducted to quantify liquid formation and vapor–solid equilibrium at high pressures. The experimental results of desublimation based cryogenic pipeline network showed promising potential for industrial exploitation.

Design and analysis of the natural gas liquefaction optimization process- CCC-ES (energy storage of cryogenic carbon capture)

The CCC (cryogenic carbon capture) process provides energy- and cost-efficient carbon capture and can be configured to provide an energy storage system using an open loop NG (natural gas) refrigeration system. This system stores energy during non-peak times by liquefying and storing natural gas to be used as a refrigerant. This investigation compares four different natural gas liquefaction processes simulated by Aspen HYSYS as incorporated as part of the CCC-ES process. In these processes, LNG vaporizes in the CCC process and the cold vapors return through the LNG heat exchangers exchanging sensible heat with the incoming flows. Aside from this difference, this investigation uses process designs similar to traditional LNG processes. The simulations meaningfully compare these alternative liquefaction options, eliminating differences in assumptions and process details inherent in comparing processes simulated by different authors or different codes. The comparisons include costs and energy performance with individually optimized processes, each operating at three operating conditions: energy storage, energy recovery, and balanced operation. Given similar quality turbomachinery, efficient heat exchangers in particular reduce energy input requirements and maximize energy savings and capital costs, including heat exchangers used to cool compressed gases.

Prediction and validation of external cooling loop cryogenic carbon capture (CCC-ECL) for full-scale coal-fired power plant retrofit

Bench-scale experiments and Aspen Plus™ simulations document full-scale, steady-state performance of the external cooling loop cryogenic carbon capture (CCC-ECL) process for a 550MWe coal-fired power plant. The baseline CCC-ECL process achieves 90% CO2 capture, and has the potential to capture 99+ % of CO2, SO2, PM, NO2, Hg, and most other noxious species. The CCC-ECL process cools power plant flue gas to 175K, at which point solid CO2 particles desublimate as the flue gas further cools to 154K. Desublimating flue gas cools in a staged column in direct contact with a cryogenic liquid and produces a CO2-lean flue gas that warms against the incoming flue gas before venting. The CO2/contacting liquid slurry separates through a filter to produce a CO2 stream that warms to 233K and partially flashes to provide a CO2-rich product. The CO2–rich product (99.2%) liquefies under pressure to form a product for enhanced oil recovery (EOR) or sequestration. All contacting liquid streams cool and cycle back to the staged column. An internal CF4 refrigeration cycle transfers heat from melting CO2 to desublimating CO2 by cooling contact liquid. An external cooling loop of natural gas or other refrigerant provides the additional heat duty to operate the cryogenic process. The nominal parasitic power loss of operating CCC-ECL is 82.6MWe or about 15% of the coal-fired power plant’s rated capacity. In different units, the energy penalty of CCC-ECL is 0.74MJe/kg CO2 captured and the resulting net power output is decreased to 467MWe. Lab- and skid-scale measurements validate the basic operation of the process along with the thermodynamics of CO2 solids formation.

Plant-level dynamic optimization of Cryogenic Carbon Capture with conventional and renewable power sources

Increasing competitiveness of renewable power sources due to tightening restrictions on CO2 emission from fossil fuel combustion is expected to cause a shift in power generation systems of the future. This investigation considers the impact of the Cryogenic Carbon Capture™ (CCC) process on transitional power generation. The CCC process consumes less energy than chemical and physical absorption processes and has an energy storage capability that shifts the parasitic loss of the CCC process away from peak hours. The CCC process responds rapidly to the variation of electricity demand and has a time constant that is consistent with the intermittent supply from renewable power sources. The hybrid system of conventional and renewable power generation units and the CCC process are optimized in this investigation. The system under consideration consists of load-following coal and gas-fired power units, a CCC process, and wind generation. The objective is to meet the residential and CCC plant electricity demands while maximizing the operating profit. The results demonstrate that an average profit of $35 k/hr is obtained from this hybrid system over the selected days. The total electricity demand is best met using a combination of coal, gas, and wind power with grid-scale energy storage.

Airy's theory of the rainbow

Cryogenic carbon capture from natural gas at high pressures requires accurate process synthesis and determination of process parameters due to the presence of solid–vapor and vapor–liquid–solid equilibria. At high pressures, the higher liquid formation not only causes operational problems, but also induces hydrocarbon losses in cryogenic packed beds. The present study proposes a novel multiple cryogenic desublimation based pipeline network with its sections at different cryogenic pressures and temperature profiles to enhance the separation. The experimental study explores the simultaneous separation of water and carbon dioxide from ternary feed gas mixture (CH4–CO2–H2O) by using multiple counter current cryogenic desublimation beds.A novel simulation strategy using multiple equilibrium temperature (MET) concept is also introduced for simulation studies. Simulation studies were subsequently conducted for both atmospheric and high cryogenic bed pressures and compared with experimental measurements. The effect of ambient humidity on dehydration was also investigated experimentally and it was observed that the humidity has significant effects on dehydration due to back diffusion. The effect of some important parameters like bed length, feed gas pressures, bed temperatures, feed flow rates and feed gas pressures for separation were investigated. Experimental investigation was also conducted to quantify liquid formation and vapor–solid equilibrium at high pressures. The experimental results of desublimation based cryogenic pipeline network showed promising potential for industrial exploitation.