A Strategy Of Mixture Preparation For Methane Direct-Fired Sco2 Combustors

Abstract

The reactor residence time required for a sCO2combustor is comparatively higher than an equal power, airdiluted conventional combustor. Therefore, the strategies toreduce the reactor residence time are very important in thedesign of sCO2 combustors. The current work recommends amethod to reduce the residence time requirement in the sCO2combustion chamber. Here, the combustor is modelled bycoupling the perfectly-stirred-reactor (PSR) and plug-flowreactor (PFR) models along with the detailed Aramco 2.0combustion chemical kinetic mechanism. The real gas effectsare considered by using the Soave-Redlich-Kwong (SRK)equation of state incorporated in CHMEKIN-RG. Though,the CO emission level at the exit of the primary zone of thesCO2 combustor is lower or in some cases equal to theconventional combustor, the further decline of CO in thedilution zone is identified as very poor. Therefore, very highCO levels can be expected at the exit of the sCO2 combustorcompared to conventional combustors. CO from the sCO2combustor exhaust can be eliminated by lean operation ofthe combustor and the excess O2 retained in the re-cycledCO2 stream due to lean operation can be mixed with primarymethane before entering the primary combustion zone. Thisstrategy is shown to reduce the primary zone residence timerequirement of sCO2 combustion. However, the minimumlevel of O2 in the re-cycled CO2 stream is approximately5000 ppm and the minimum required residence time in thispre-mixing chamber is around 4 ms. Also, it is observed thatthe primary zone residence time requirement decreaseslinearly with respect to the O2 level in the re-cycled CO2stream.

Publication Date

1-1-2018

Publication Title

Proceedings of the ASME Turbo Expo

Volume

9

Document Type

Article; Proceedings Paper

Personal Identifier

scopus

DOI Link

https://doi.org/10.1115/GT2018-75557

Socpus ID

85053872998 (Scopus)

Source API URL

https://api.elsevier.com/content/abstract/scopus_id/85053872998

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