Process Integration of Calcium Looping Technology
Abstract
Around 36 gigatonnes of CO₂ are released into the atmosphere every year. Mitigation of CO₂ emissions is essential in reducing the rising level of greenhouse gas emissions and associated climate change. Calcium Looping Process (CLP) is one of the promising technologies developed as part of the continuous efforts for Carbon Capture and Utilization (CCU). It is essentially a CO₂ capture process that utilizes calcium oxide (CaO) as a sorbent for the removal of CO₂, producing a concentrated stream of CO₂ (~99%) that is suitable for storage and reuse is produced in this process. Although still in the pilot stage, CLP presents several advantages over conventional carbon capture systems like amine-scrubbing. These advantages include low cost of the sorbent and relative ease of bolt-on retrofitting of existing power plants and industrial processes. The objective of this work is to use mass and energy integration to couple CLP with industrial facilities and power plants in order to enhance industrial symbiosis and reduce cost. Special attention is given to plants that generate large amount of CO₂ and/or provide excess heat that can be used in driving CLP. A case study was solved to assess the integration of CLP with candidate processes including power plants, cement production, gas-to-liquid (GTL) facility, and ammonia synthesis. The captured CO₂ can be re-utilized in CO₂ sinks that utilize CO₂ as a raw material for making chemicals. This use of CO₂ as a chemical feedstock provides a suitable alternative to sequestration and storage. The CO₂ sinks considered in the case study include the production of: urea, polymer, methanol and acetic acid. The solution to the case study shows the merits for integration of a GTL plant with CLP to supply CO₂ for the production of a polymer, methanol and acetic acid. Additionally, the captured CO₂ stream from the ammonia plant is integrated with urea production. Excess heat from the GTL facility and the power plant were also used. Cogeneration of power and heat improves the economic feasibility of the integrated system. The highlights of this symbiosis are the re-use of waste calcium oxide from the cement plant, utilization of waste heat and reduction of CO₂ emissions and raw-material usage due to utilization of the captured CO₂
Citation
Tilak, Pooja (2017). Process Integration of Calcium Looping Technology. Master's thesis, Texas A & M University. Available electronically from https : / /hdl .handle .net /1969 .1 /165894.