This Small Business Innovation Research (SBIR) Phase II project will stimulate the acceptance of carbon capture by companies that own and operate coal-fired plants. The Department of Energy considers the amine absorption of carbon dioxide (CO2) from flue gas of coal-fired power plants as the most advanced, most well understood, and most successful method for carbon capture. In this process, monoethanolamine (MEA) solvent is used in a thermal process for desorption and carbon capture. Unfortunately, the thermal process is very inefficient, requiring a 30% increase in coal usage for to capture the CO2. The Phase I research proved the feasibility of replacing the inefficient thermal process with a new, innovative photolytic process that has the potential to dramatically cut the 30% increase in coal usage by more than half. The first part of the Phase II project will focus on developing an efficient photolytic prototype reactor that will dramatically reduce the costs of capturing CO2 as preparation for field tested at a power plant. The Phase II objectives will focus first on optimizing the reactor processes that affect desorption and capture. Then, using the resulting data, the team will design and build the prototype reactor.
The broader impacts of this research are that it has the potential to make carbon capture at coal fired power plants significantly more cost effective for the power producer. For example, by retrofitting the photolytic technology, a 100-500 MWe power plant could save as much as $17 MM annually. With this type of saving, an investment by a power plant in the photolytic technology is likely to produce a very high rate of return, whereby the cost of adding the photolytic reactor process could be recouped in approximately three years. The World Coal Institute reports that coal‟s share of global electricity generation is set to increase from 41% to 44% by 2030. In the United States, electricity generation accounts for approximately 40% of total CO2 emissions and more than 80% of these emissions come from coal fired power plants. Near-term CO2 capture technologies raise the cost of electricity (COE) produced at these plants by 60-90%, and impose a 25-35% parasitic coal-burning load. As the U.S. searches for ways to reduce CO2 emissions, maintaining coal as a viable source of low-cost electric power critically depends on finding more cost effective ways to capture the CO2 produced. The energy efficient photolytic process developed in this project has the potential of reducing the increase in the COE for carbon capture from the current 60-90% for the thermal process to less than 35%.
Intellectual Merit: The Department of Energy considers the amine absorption of carbon dioxide (CO2) from flue gas of coal-fired power plants as the most advanced, most well understood, and most successful method for carbon capture. In this process, monoethanolamine (MEA) solvent is used in a thermal process for desorption and carbon capture. Unfortunately, the thermal process is very inefficient, requiring a 30 % increase in coal usage for the CO2 capture. Pearlhill’s Phase I research proved the feasibility of replacing the inefficient thermal process with a new, innovative photolytic process that has the potential to dramatically cut the 30 % increase in coal usage by more than half. In Phase II, a flow model was developed by using the k-epsilon turbulence model. The model was developed as a 2D model in the Chemical Engineering toolbox of COMSOL (v3.5a). A steady state 3D model of the system in the CFX solver was used to solve the governing Navier-Stokes equations coupled with k-epsilon turbulence model. Modeling of the fluids was achieved. Computing the UV fluence of MEA-CO2 achieved a convergence by using the Helmholtz equations for excitation light. The residuals of mass and momentum also converged. For convergence of the dissipation and kinetic energy in the system, the project used a particle tracking method in CFX v14.5 program to monitor the path line of the reaction products, and coupled it with fluence calculations. Photocatalysis caused an improvement of the rate of CO2 separation from the MEA scrubber within an early brief period, and this was followed by a sudden sharp drop in activity – likely the result of a combination of catalyst aggregation at high concentrations and catalyst degradation. We developed an efficient photolytic prototype reactor that will dramatically reduce the costs of capturing CO2. The Phase II objectives focused first on optimizing the reactor processes that affect separation and capture. Then, using the resulting data, we designed and built the prototype reactor to stimulate the acceptance of carbon capture by energy companies that own and operate coal-fired plants. Broad Impact: The World Coal Institute reports that coal’s share of global electricity generation is set to increase from 41 – 44 % by 2030. In the United States, electricity generation accounts for approximately 40% of total CO2 emissions and more than 80 % of these emissions come from coal fired power plants. Near-term CO2 capture technologies raise the cost of electricity (COE) produced at these plants by 60 – 90 %, and impose a 25 – 35 % parasitic coal-burning load. As the U.S. searches for ways to reduce CO2 emissions, maintaining coal as a viable source of low-cost electric power critically depends on finding more cost effective ways to capture the CO2 produced. Pearlhill’s energy efficient photolytic process has the potential of reducing the increase in the COE for carbon capture from the current 60 – 90 % for the thermal process to less than 35 %. Pearlhill estimates that by retrofitting the photolytic technology, a 100 – 500 MWe power plant could save as much as $17 MM annually. With this type of saving, an investment by a power plant in the photolytic technology is likely to produce a very high rate of return.
