순산소 재순환 연소를 채택한 3 ㎿급 CO₂ 회수형 보일러의 연소 특성

안준(Joon Ahn),김혁주(Hyuock Ju Kim),최규성(Kyu Sung Choi) 대한기계학회 2019 大韓機械學會論文集B Vol.43 No.3

본 연구에서는 공기 연소, 순산소 연소, 순산소 재순환 연소를 적용할 수 있는 동축형 버너를 개발하고 이를 3 ㎿급의 노통연관식 보일러에 설치하여 연소 및 배가스 특성을 실험하였다. 유사한 설계의 버너를 채택한 0.5 ㎿급의 보일러에서 얻은 결과와 비교하여 스케일 업 특성을 확인하고 안정된 화염을 얻을 수 있는 재순환율을 비교하였다. 연료공급량과 연료-산화제 비율을 변화하며 연소 특성을 파악하였고 각각의 조건에서 배가스를 분석하였다. 분석 결과 순산소 연소를 산업용 보일러에 적용함으로써 이산화탄소를 분리할 수 있고 질소 산화물의 배출을 크게 줄일 수 있음을 확인하였다. 그러나 순산소 연소를 적용할 경우 부분 부하 조건에서 안정된 화염을 얻기 어렵고 용량이 변화하면 안정된 화염을 얻을 수 있는 재순환율이 달라짐을 확인하였다. In this study, a coaxial type burner capable of applying air combustion, oxy-fuel combustion, and oxy-fuel oxygen combustion with FGR (flue gas recirculation) was developed and tested for combustion and exhaust gas characteristics by installing it in a 3 ㎿ class flame-tube type boiler. Compared with the results obtained from a 0.5 ㎿ class boiler with a similar burner, the scaled-up characteristics were verified and the recirculation rates for a stable flame were compared. Combustion characteristics were investigated by varying fuel supply rate and fuel-to-oxidizer ratio, and the flue gas was analyzed under each condition. Consequently, it was confirmed that carbon dioxide can be separated, and NOx emissions can be reduced by applying oxy-fuel combustion to industrial boilers. However, it was discovered that it is difficult to obtain a stable flame under partial load conditions when oxy-fuel combustion is applied and that this changes the recirculation rate that can yield a stable flame for a burner with a different capacity.

A mode transition strategy from air to oxyfuel combustion in a 35MW coal-fired power plant boiler

Zixue Luo,Wenfeng Cheng,Bo Wu,Yongchun Zhao,Junying Zhang 한국화학공학회 2017 Korean Journal of Chemical Engineering Vol.34 No.5

The atmosphere under the conditions of a coal combustion reaction in the furnace is the factor that makes the most significant difference during mode transition from traditional air to oxy-fuel combustion. The flue gas is adopted as the primary air and secondary air for pulverized-coal conveying and the support of combustion; it has a high carbon dioxide concentration during the oxy-fuel combustion. The air-leakage reduces CO2 enrichment and leads to thermal NOx production. A control strategy of this shift operation is conducted in a 35MW oxy-fuel combustion power plant boiler by adjusting the furnace pressure, regulating the recirculation rate of the flue gas and amending the oxygen concentration in the inlet stream. The furnace pressure can be changed smoothly and stabilized at a micro-positive level as the pressurized air flow is monitored at a suitable range. The combustion-supporting flue gas is modified by the oxygen content in the furnace outlet, and the circulation rate of the flue gas verifies the regulation process. Results show that the CO2 concentration in the flue gas can be rapidly increased along with the increment of furnace pressure and oxygen in the inlet stream; then, this procedure gradually becomes flattened. The CO2 content in the flue gas correlates with the recirculation rate of the flue gas and oxygen concentration in the inlet stream. The two operation parameters should be maintained at a high CO2 concentration in a range from 0.6-0.7 and 29.5%-30.5%, respectively. Sampling analysis shows that SO2 and NOx emissions were 26 (±1.5) mg/MJ and 90 (±11.7) mg/MJ in air condition, 14 (±0.4) mg/MJ and 34 (±1.6) mg/MJ in oxy-fuel combustion; the burnout rate, mechanical losses of incomplete combustion and the unburned carbon rate remained similar at these two stable combustion modes. This mode transition scheme should provide a reference for monitoring and diagnostics, design and operation control of an oxygen-enriched pulverized-coal combustion power plant boiler.

순산소 재순환 연소를 채택한 CO₂ 회수형 보일러 개발

안준(Joon Ahn),김혁주(Hyouck Ju Kim),최규성(Kyu Sung Choi) 대한기계학회 2008 대한기계학회 춘추학술대회 Vol.2008 No.5

A 0.5 ㎿ class oxy-fuel boiler has been developed to capture CO₂ from the exhaust gas. FOR (flue gas recirculation) is adopted to be compliant with the retrofit scenario. Condensing economizer is added to maximize the system efficiency. The portion of heat absorbed at the combustion chamber has been increased for the oxy-fuel combustion due to the reduced flow rate and gas radiation. The radiation inside flame tubes becomes significant for the oxy-fuel combustion. Due to higher dew point, the condensing economizer is more effective for the oxy-fuel mode.

Power-to-Gas 플랜트 연계 순산소 연소 보일러 공정 해석

손근(Geun Sohn),류주열(Ju-Yeol Ryu),박혜민(Hye-Min Park),박성호(Sung-Ho Park) 한국열환경공학회 2021 열환경공학 Vol.16 No.1

Power-to-Gas(PtG) is a promising technology that produces hydrogen by the electrochemical reaction in water electrolyzer to manage the intermittent power generation from renewable energy such as wind and solar. Water electrolyzer generates hydrogen and highly purified oxygen as a by-product. In this study, the process was examined in coal fired oxy-fuel combustion power plant and in PtG plant to use highly purified oxygen obtained from water electrolyzer. The power generation efficiency of a coal-fired oxy-fuel power plant supplied with oxygen through an air separation unit and that of a coal-fired oxy-fuel power plant supplied with oxygen in a polymer electrolyte membrane (PEM) water electrolysis process were compared. As a result of the analysis, in the case of the combined system of the coal-fired oxy-fuel power plant and the PtG plant, the net power generation and power generation efficiency were higher than the case of individual coal-fired oxy-fuel power plant supplied with oxygen through the air separation unit. The process efficiency is further improved when using biomass, fueling the oxy-fuel combustion boiler rather than coal and when steam-water is in supercritical conditions.

순산소 재순환 연소를 채택한 CO₂ 회수형 보일러 개발

안준(Joon Ahn),김혁주(Hyouck Ju Kim),최규성(Kyu Sung Choi) 대한기계학회 2007 대한기계학회 춘추학술대회 Vol.2007 No.10

A 0.5 ㎿ class oxy-fuel boiler has been developed to capture CO₂ from the exhaust gas. Based on the previous 50 ㎾ model test, the sealing of the system has been improved and FGR (flue gas recirculation) has been tried. Condensing economizer has been added to sequestrate CO₂ by the heat exchange with oxygen evaporator. Oxy-fuel combustion yields stretched flame to uniformly heat the combustion chamber. It also provides the high CO₂ concentration, which is over 90% in dry base. However, pure oxy-fuel combustion increases NO concentration, because of the reduced flow rate. The FGR can suppress the thermal NOx induced by the infiltration of the air.

Oxy-fuel combustion boiler for CO2 capturing: 50 kW-class model test and numerical simulation

안준,김혁주,최규성 대한기계학회 2010 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.24 No.10

A novel oxy-fuel burner was devised and integrated into a 50 kW-class furnace-type boiler system. A series of experiments was conducted to verify its feasibility for industrial applications. Additionally, numerical simulations were performed and the results validated against experimental data on the detailed physics inside the conventional-design combustion chamber. The oxy-fuel burner, with the help of gas radiation, could effectively heat the combustion chamber. The composition of the exhaust gas revealed that the sealing of the system is crucial to the achievement of high CO2 concentrations and low NOx emissions.

순산소 연소를 채택한 CO₂ 회수형 보일러의 성능특성

안준(Joon Ahn),김혁주(Hyouck Ju Kim),최규성(Kyu Sung Choi) 대한기계학회 2007 대한기계학회 춘추학술대회 Vol.2007 No.5

A novel oxy-fuel burner for a boiler has been devised and composed into a 50 ㎾ class boiler system. A series of test has been conducted to show the characteristics of combustion, exhaust gas and the boiler. Numerical simulations have been also performed and validated against the experimental data to discuss detailed physics. The oxy-fuel burner can effectively heat the combustion chamber with the significantly reduced combustion gas, which enables to realize the compactness of the system. The composition of exhaust gas reveals that the sealing of the system is crucial to achieve high CO₂ concentration and low NOx emission.

순산소 재순환 연소를 채택한 CO₂ 회수형 보일러 연소실에 대한 수치해석

안준(J. Ahn),김혁주(H.J. Kim) 한국전산유체공학회 2009 한국전산유체공학회 학술대회논문집 Vol.2009 No.4

An oxy-fuel boiler has been developed to capture CO₂ from the exhaust gas. FGR (flue gas recirculation) is adopted to be compliant with the retrofit scenario. Numerical simulations have been performed to study the detailed physics inside the combustion chamber of the boiler. The temperature field obtained from the simulation agrees with the flame image from the experiment. The FGR combustion yields similar heat transfer characteristics with the conventional air combustion while the flame is formed further downstream in case of the FGR combustion.