Analysis of the flue gas in an iron oxide-semirara coal chemical looping combustion system

• Main Authors: Gothong, Christian Bennett O., Maalala, Jerric Andrei G., Quedi, Boris Brian B.
• Format: text
• Language: English
• Published: Animo Repository 2014
• Online Access: https://animorepository.dlsu.edu.ph/etd_bachelors/11884
• Institution: De La Salle University

Chemical looping combustion, a carbon capture method comprising of an oxygen carrier and a fuel for its experimentation, is capable of operating without the energy intensive carbon dioxide separation. It also minimizes nitrous oxide formations, and produces water and CO₂ separately. For cost minimization, iron oxide from scrap iron was used with Semirara coal as the oxygen carrier and fuel, respectively. The effects of temperature, oxygen carrier-fuel ratio and cycles on the flue gas wre investigated in order to determine the best conditions for producing the most CO₂. Additionally, the TG profile composition of flue gas and comparison of theoretical and actual CO₂ were also determined. Temperatures used were 800, 900 and 1000⁰C, and oxygen carrier-fuel ratios were 7:1, 8.5:1, and 10:1. The two best runs were tested for the effect of cycles up to 5 cycles each. The coal and scrap iron were sieved to Tyler equivalent 150 mesh. The oxygen carrier was heat treated at 950⁰C until the weight no longer changed, which gained an average of 39% weight increase. Upon research and calculations, it was determined dthat the scrap iron after oxidation is Fe₃O₄. Material balance was performed to calculate the composition of the reduced iron oxide, which was calculated to be FeO. Based on the data gathered, the 7:1 ratios at 800 and 900⁰C obtained the best results of CO₂ at 20 and 24 ppm, respectively but also had a high CO yield of 12430 and 16580 ppm. The high CO yield could be attributed to the incomplete reduction that occurred in the system which resulted in incomplete combustion. Temperature had no effect since reduction occurred before the hold temperature was reached. Best ratio is 7:1, having conversations of 10.147%, 13.570%, and 8.748%. As for the cycles, amount of CO₂ decreased as the number of cycles was increased until no CO₂ was detected.