Carbon-capture-system feasibility study

Analysis demonstrates scalability of innovative carbon-capture concept

A typical 550 MWe coal-fired power plant emits approximately five million tons of carbon dioxide (CO₂) into the atmosphere every year. Growing concern over power-plant greenhouse gas emission rates and their impact on climate change has prompted the Department of Energy (DOE) to fund ongoing research related to developing more cost-effective carbon capture technologies.

Starting around 2010, the DOE funded 14 carbon-capture research projects through the Small Business Innovation Research (SBIR) and Small Business Technology Transfer (STTR) program. The SBIR and STTR funding vehicles allow federal agencies to assign a portion of their research and development budgets as set asides for encouraging product development by small businesses.

Envergex LLC, a small business, and The Institute for Energy Studies (IES) at the University of North Dakota (UND) have been developing a dry-sorbent technology for capturing and removing up to 90% of carbon dioxide from existing fossil-fuel-fired power plant flue gases, using funding from the SBIR/STTR and other federally funded programs. Their novel, solid-sorbent technology (Capture of CO₂ by Hybrid Sorbents - CACHYS™) is based on the following ideas:

• Reduction of energy for sorbent regeneration

• Utilization of novel process chemistry

• Flue gas-sorbent contactor conditions that minimize sorbent CO₂ heat of reaction and promote fast CO₂ capture

• Use of a low-cost sorbent and low-cost methods of heat management

From 2012 to 2015, Barr conducted technical and economic feasibility analyses of the innovative hybrid CACHYS^TM technology for CO₂ capture and separation from coal-combustion-derived flue gas for installation at a 550 MW_e coal-fired power plant. (The 550 MW_e is a standard size used by DOE-funded research projects for equivalent comparisons.)

Barr’s analysis to evaluate the techno-economic feasibility of the CO₂ capture process was based on a combination of laboratory test results as well as ASPEN Plus process modeling studies conducted by Envergex LLC and UND. Barr reviewed the process and the engineering foundation used to create the process flow diagrams and the design basis. Next, we identified the major equipment required per the process flow diagram and formulated general arrangement drawings. Equipment sizing and cost estimates followed.

The preliminary work and Barr’s evaluation comprised the first of multiple phases for this technology development. The next phase involved updating the techno-economic study by Barr based on the test results from a pilot plant that applied the CACHYS^TM process to a boiler slipstream at the university’s campus. We anticipate a small demonstration plant as the next developmental step for example, the treatment and CO₂ capture of a fraction (5 to 10 percent) of a power plant flue gas stream. If successful, these phases would lead to the installation of a commercial-scale CACHYS system at a utility coal-fired power plant. The technology can also be installed for natural gas-fired combined cycle systems and is equally applicable to both small and large power plants.