Competition between H₂O and CO₂ for active sites during co-gasification of bituminous coal and pineapple sawdust in an atmosphere containing H₂O, CO₂, H₂, and CO

Massoudi Farid, Massoud,Hwang, Jungho Elsevier Ltd 2017 Fuel Vol.207 No.-

<P><B>Abstract</B></P> <P>The competition between the H<SUB>2</SUB>O and CO<SUB>2</SUB> for the active sites during gasification remains a controversial issue in the literature. In this study, the competition between the H<SUB>2</SUB>O and CO<SUB>2</SUB> for the active sites during gasification of coal, biomass, and a mixture of coal and biomass using the Langmuir–Hinshelwood (L–H) kinetic parameters obtained in our previous two papers (Massoudi Farid et al., 2016, 2017) was investigated. It was found that the char–H<SUB>2</SUB>O and char–CO<SUB>2</SUB> reactions occurred on separate active sites for all samples. For a constant CO<SUB>2</SUB> concentration, increasing the H<SUB>2</SUB>O concentration caused an increase in the kinetic coefficient. The extent to which the kinetic coefficient increased became less pronounced as the amount of biomass in the co-gasified mixture increased. For a constant H<SUB>2</SUB>O concentration, increasing the CO<SUB>2</SUB> concentration also increased the kinetic coefficient; however, the extent to which the kinetic coefficient increased was greater when the amount of biomass was higher. Additional experiments were conducted to study the effect of the co-existence of H<SUB>2</SUB> and CO on the competition between the char–H<SUB>2</SUB>O and char–CO<SUB>2</SUB> reactions for the active sites. It was found that the char–H<SUB>2</SUB>O and char–CO<SUB>2</SUB> reactions also occurred on separate active sites, even in the presence of both H<SUB>2</SUB> and CO.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Coal–biomass blended char was gasified in a mixture of CO<SUB>2</SUB>, H<SUB>2</SUB>O, H<SUB>2</SUB>, and CO. </LI> <LI> Char–H<SUB>2</SUB>O and char–CO<SUB>2</SUB> reactions occurred on separate active sites. </LI> <LI> H<SUB>2</SUB> and CO had no effect on participation of active sites in the gasification. </LI> </UL> </P>

Kinetic study on coal-biomass mixed char co-gasification with H₂O in the presence of H₂

Massoudi Farid, M.,Jeong, H.J.,Hwang, J. Butterworths [etc.] ; Elsevier Science Ltd 2016 Fuel Vol.181 No.-

The coal-biomass mixed char co-gasification with H<SUB>2</SUB>O in the presence of H<SUB>2</SUB> was investigated under atmospheric conditions using a tube furnace and gas analyzer. Various partial pressures of H<SUB>2</SUB>O and H<SUB>2</SUB> were tested within a temperature range of 825-900<SUP>o</SUP>C. Bituminous coal, pineapple sawdust, and a mixture of these two having a mass ratio of 1:1 were used to prepare chars. Random pore model was utilized to explain the experimental results. The results demonstrated that the inhibition effect of H<SUB>2</SUB> on char-H<SUB>2</SUB>O gasification can be described using the Langmuir-Hinshelwood (L-H) equation. The inhibition effect on the mixture sample was more intense than on the pure samples. The L-H equation kinetic parameters were acquired and expressed in an Arrhenius equation form to determine the pre-exponential factor and activation energy.

The effect of CO on coal–biomass co-gasification with CO₂

Massoudi Farid, Massoud,Kang, Myung Soo,Hwang, Jungho Elsevier 2017 Fuel Vol.188 No.-

<P><B>Abstract</B></P> <P>In this study, co-gasification of coal and biomass chars with CO<SUB>2</SUB> in the presence of CO was investigated at three different temperatures: 850, 875, and 900°C. A coal–biomass (bituminous-pineapple sawdust) mixture with a mass ratio of 1:1 was used for devolatilization and co-gasification. Random pore model was employed to determine the kinetic coefficient from experimentally obtained carbon conversion data. The Langmuir–Hinshelwood (L–H) equation, which has been widely used in literatures to describe the relationship between kinetic coefficient of the gasification and partial pressures of reacting gases, effectively represented the inhibition effect of CO on char–CO<SUB>2</SUB> gasification. The kinetic parameters of the L–H equation were acquired from the experimental data. The activation energy (<I>E</I>) and pre-exponential factor (<I>A</I>) of each kinetic parameter of L-H equation were obtained using the Arrhenius equation. CO inhibition effect was more powerful in the Char-CO<SUB>2</SUB> co-gasification of the mixed sample compared to those in the unmixed samples. Further, for each sample, the inhibition effect was stronger at lower temperature owing to a smaller number of active sites.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Coal–biomass blended char was gasified with CO<SUB>2</SUB> in the presence of CO. </LI> <LI> Inhibition effect of CO on char-CO<SUB>2</SUB> gasification was studied. </LI> <LI> Langmuir–Hinshelwood (L-H) equation was used to describe the CO inhibition effect. </LI> <LI> Random pore model was used to interpret the carbon conversion data. </LI> <LI> L–H kinetic parameters were obtained and expressed in an Arrhenius equation form. </LI> </UL> </P>

Numerical investigation of effects of coal feeders position and coal feeding rate on particle transport hydrodynamics and coal combustion in an industrial scale circulating fluidized bed furnace

Massoud Massoudi Farid,Hyo Jae Jeong,Keun Ho Kim,Jungho Hwang 한국연소학회 2015 KOSCOSYMPOSIUM논문집 Vol.2015 No.5

This study investigates the effects of coal feeders position and coal feeding rate on particle transport hydrodynamics and coal combustion in an industrial scale circulating fluidized bed furnace using Dense Discrete Phase Model (DDPM) of ANSYS FLUENT. Several user defined functions (UDF) were used to extend ANSYS FLUENT original code. Results of two different coal feeders positions and coal feeding rates were displayed and compared with operating data obtained from a 340 MWe CFB boiler located in Yeosu, South Korea.

새로운 샘플러: 바이오-루미센스 상용 면봉 키트를 이용한 공기 중 세균의 신속한 측정방법

김도헌,오재호,Milad Massoudi Farid,신동민,최상수,황정호,변정훈 한국대기환경학회 2021 한국대기환경학회 학술대회논문집 Vol.2021 No.10

코로나19 사태가 지속됨에 따라 실내외 공기중 미생물(바이오 에어로졸) 감지에 대한 관심도가 계속해서 높아지고 있다. 실내외 공기질을 포집하고 측정 및 감지하기 위한 방법들은 많이 있지만, 포집부터 감지하는데 걸리는 시간이 길어 실시간으로 정확한 실내외 공기질 측정은 어려운 상황이다. 이를 극복하기 위한 대안으로 바이오-루미센스 반응을 통해 미생물을 측정하는 상용 ATP 측정 면봉 키트를 사용하여 5분 만에 목표로 하는 크기의 에어로졸 내 바이오 에어로졸의 포집 및 측정이 가능한 샘플러를 제작하였다. 샘플러의 구조는 유입구, 면봉 포집부와 증기 발생기, 디퓨전 드라이어, 펌프, 배출구로 되어 있고 유입구에 임팩터를 장착하여 에어로졸의 크기에 따른 포집을 할 수 있다. 이후, CFU (Colony Forming Unit)과 RLU (Relative Light Unit)의 관계, 바이오 에어로졸 농도와 RLU의 관계를 확인하여 해당 샘플러의 타당성을 증명하고 사용 프로토콜을 최적화 하였다. 해당 샘플러와 앤더슨 임팩터로 다중 이용 시설인 신촌역, 영남대 병원 등에서 필드 테스트를 하였고, 바이오 에어로졸의 여부를 RLU 데이터와 CFU 데이터를 통해 측정할 수 있었으며, 필드에서의 RLU와 CFU 값의 상관관계를 알 수 있었다. 따라서 해당 샘플러를 사용하여 측정된 RLU 값을 통해 공기중 미생물의 농도를 대략적으로 알 수 있어 실내외 바이오 에어로졸을 포함한 공기질 정보를 실시간으로 보다 빠르고 쉽게 알 수 있게 된다. 그리고 임팩터를 장착시켜 목표로 하는 크기의 에어로졸 포집 및 측정이 쉽게 가능하여 바이오 에어로졸을 보다 효율적으로 분석할 수 있게 된다.

Effect of staged combustion on low NOx emission from an industrial-scale fuel oil combustor in South Korea

Kang, Myung Soo,Jeong, Hyo Jae,Massoudi Farid, Massoud,Hwang, Jungho Elsevier 2017 Fuel Vol.210 No.-

<P><B>Abstract</B></P> <P>Staged combustion induces the reduction of NO to generate N<SUB>2</SUB> through the formation of a fuel-rich zone upstream of the flue gas and utilizes the unburned gas by supplying sufficient air for combustion downstream of the flue gas. Since power generation schedules are very constrained and only specific and limited tests can be planned and executed, the use of numerical simulations is currently more suitable for analyzing these large and complex systems. In this study, computational fluid dynamics (CFD) simulation was performed for an industrial-scale fuel oil combustor to determine the effect of staged combustion on NOx emissions. The fuel oil combustor is a 400-MWe opposite-wall unit located in Ulsan, South Korea, where high-sulfur fuel oil (Bunker-C with 2.5% sulfur content) is used. The combustor has a height of 56m and a cross-sectional area of 10×12m<SUP>2</SUP>. Water wall tubes (evaporator) are located on the wall of the lower part of the combustor and sixteen burners are located at four different axial positions. The system is comprised of two superheaters, two reheaters, and an economizer located in the upper part of the combustor. Staged combustion is realized by changing the equivalence ratio of each burner. Under the initial staged combustion conditions adopted by the Ulsan power plant, the concentration of NOx at the exit of the combustor was calculated to be 362ppm, which was still high even after selective catalytic reduction treatment. However, when more stringent staged combustion conditions were applied, the predicted concentration of NOx decreased to 309ppm, which is lower than the mandated NOx concentration at the combustor exit.</P> <P><B>Highlights</B></P> <P> <UL> <LI> CFD simulation was carried out for an industrial-scale fuel oil combustor. </LI> <LI> Ideal operating conditions were determined by using stringent staged combustion. </LI> <LI> NOx emission decreased with proposed conditions compared to reference conditions. </LI> <LI> The decrease of NOx emissions was mainly caused by thermal NOx formation decrease. </LI> <LI> The theoretical CFD results were in good agreement with experimental data. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Real-time separation of aerosolized <i>Staphylococcus epidermidis</i> and polystyrene latex particles with similar size distributions

Mohamadi Nasrabadi, Ali,Han, Jang Seop,Massoudi Farid, Milad,Lee, Sang-Gu,Hwang, Jungho Informa UK (TaylorFrancis) 2017 AEROSOL SCIENCE AND TECHNOLOGY Vol.51 No.12

<P>For rapid and effective detection of airborne microorganisms, it is preferable to remove dust particles during the air sampling process because they can reduce the detection accuracy of measurements. In this study, a methodology of real-time separation ofaerosolized Staphylococcus epidermidis (S. epidermidis) andpolystyrene latex (PSL) particles of similar size was investigated. These two species represent biological and non-biological particles, respectively. Due to their different relative permittivities, they grasp different numbers of air ions under corona discharge. After these charged particles enter a mobility analyzer with airflow, in which an electric field is applied perpendicular to the airflow, the S. epidermidis and PSL particles separate, due to the difference in their electric mobilities, and exit through two different outlets. Purities and recoveries for S. epidermidis and PSLat their respective outlets were determined with measurements of aerosol number concentrations and ATP bioluminescence intensities at the inlet and two outlets. The results were that purities for PSL and S. epidermidis were 70% and 80%, respectively. This methodology provides a rapid and simple way to increase the detection accuracy of bacterial agents in air.</P>

Real-time separation of aerosolized Staphylococcus epidermidis and polystyrene latex particles with similar size distributions

Mohamadi Nasrabadi, Ali,Han, Jang Seop,Massoudi Farid, Milad,Lee, Sang-Gu,Hwang, Jungho Taylor Francis 2017 AEROSOL SCIENCE AND TECHNOLOGY Vol.51 No.12