Session: 17-08-01: Posters Related to Energy

Paper Number: 99198

99198 - Ammonia Co-Firing Characteristics in a 100 Kwth Circulating Fluidized Bed Combustion Test Rig 

According to the 2050 carbon neutrality scenario policy in South Korea, there are two plans in power (electricity generation) sector that one is the shut-down of both coal-fired and LNG-fired power plants, and another is only shut-down of coal-fired power plants, and some LNG power plants are maintained until 2050. In addition, it should be reduced greenhouse gas amount (291 Mt CO₂eq) by 2030 based on greenhouse gas production (727.6 Mt CO₂eq) in 2018 according to the 2030 NDC policy in South Korea. In order to implement the reduction amount, coal-fired power plant with ammonia as a carbon free fuel is emerging as an alternative technology. Among energy mixes in 2030, thermal power generation with ammonia will be accounted for 22.1 TWh. The proportion of this power generation is 3.6% of total (612.4 TWh). Electricity generation derived from ammonia co-firing can not only help achievement of RE100, but also cope with carbon border adjustment mechanism (CBAM) in the industry fields. From these needs, some researches on thermal power using ammonia as fuel have been conducting since 2021 in South Korea.

This study was also performed with a 100 kW_th circulating fluidized bed combustion (CFBC) test rig to obtain the knowledge for ammonia co-firing operating technology. The aim of this study was to investigate the effect of ammonia co-firing ratio (0, 6.2, 10.2, 17.5 % as thermal input basis) and ammonia injecting positions (dense bed at 0.2 m, and down-comer) on combustion characteristics such as temperature profile in the combustor, pollutant emissions (NO, N₂O, CO, SO₂), and NH₃ slip for ammonia co-firing with biomass.

In terms of ammonia co-firing operating, flue gas temperature leaving the combustor slightly increase from 700 (only biomass pellet firing without ammonia) to 720 ^oC with increasing ammonia co-firing ratio. NO emission dramatically decreased from 120.5 ppm with only biomass firing to 66.5 ppm at 10.2 % ammonia co-firing ratio and 27.5 ppm at 17.5 % ammonia co-firing ratio. The reason is the fact that some of ammonia play a role as reductant for selective non-catalytic reduction (SNCR). However, despite high average temperature (880 ^oC) in the combustor and sufficient O₂ supply (O₂ concentration over 4 vol.% in flue gas), CO emission significantly increased from 14.7 ppm without ammonia co-firing to 1499.1 ppm at 17.5 % ammonia co-firing. N₂O contents under ammonia co-firing were slightly higher than that of only biomass firing, while there were below 50 ppm under all conditions. Moreover, with increasing ammonia co-firing ratio, NH₃ slip increased from 20 ppm at 10.2 % ammonia co-firing to 200 ppm at 17.5 % ammonia co-firing, but un-reacted NH₃ was perfectly absorbed in the water scrubber.

Considering ammonia injecting position under similar ammonia co-firing ratios (10.1-10.2 % as thermal input basis), when ammonia gas was injected with circulating solids in down-comer between loop-seal and combustor, flue gas temperature exiting the combustor was slightly lower than that of injecting in dense zone at 0.2 m based on the distributor. Additionally, NO and CO emission during operating injected in down-comer were higher than those of experiment injected in dense zone due to short residence time and lower solid-gas mixing.

Finally, it revealed that CO₂ emission decreased about 10 % due to feeding amount reduction of biomass (carbon source) regardless ammonia injection position in similar ammonia co-firing operating.

This work was conducted under the framework of Research and Development Program of the Korea Institute of Energy Research (KIER) (C2-2437).

Presenting Author: Seong-Ju Kim Korea Institute of Energy Research

Presenting Author Biography: I’m a post-doctral researcher in Korea Institute of Energy Research (KIER) funded by South Korea government. My research fields are the the oxy-combustion with circulating fluidized bed combustion for CO2 capture, and ammonia co-firing for CO2 reduction. Also, i have studied the production of bio-liquid fuels through hydrothermal fractionation and liquefaction.

Authors:

Seong-Ju Kim Korea Institute of Energy Research
Tae-Young Mun Korea Institute of Energy Research
Sung-Jin Park Korea Institute of Energy Research
Sung-Ho Jo Korea Institute of Energy Research
Sang Jun Yoon Korea Institute of Energy Research
Ji Hong Moon Korea Institute of Energy Research
Jae-Goo Lee Korea Institute of Energy Research