• Title/Summary/Keyword: circulating fluidized bed combustion fly ash

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Development of Non-cement Material using Recycled Resources (유동층연소방식 석탄재를 활용한 무시멘트 결합재)

  • Mun, Kyoung-Ju;Lee, Min-Hi;Yoon, Seong-Jin
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2014.11a
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    • pp.156-157
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    • 2014
  • Inorganic binding material was made by recycled resource and its applicability as pile-filling material was examined. The result was that the material had same liquidity with the liquidity of OPC and high reactivity with site soil. According to dynamic/static loading tests by site test-construction, the inorganic binding material met both design bearing capacity and settlement. Since the inorganic binding material showed same or better performance than OPC, the utilization possibility of the inorganic binding material made of recycled resource as pile-filling material was verified.

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Properties of Cement Mortar According to Substitution Ratio of High Calcium Fly Ash Based on Blast Furnace Slag (고로슬래그 기반 고칼슘 플라이애시 치환비율에 따른 시멘트 모르타르의 특성)

  • Cho, Seong-Woo;Mun, Kyung-Ju;Hyung, Won-Gil
    • Journal of the Korea Institute of Building Construction
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    • v.20 no.1
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    • pp.27-34
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    • 2020
  • In the industry, due to the carbon dioxide gas produced during cement production is increasing, research on recycling by-products has been actively conducted. In the industrial by-products, the high calcium fly ash(HCFA) produced by the blast-furnace in the circulating fluidized bed combustion method has a high ratio of CaO and CaSO4. In view of this, the purpose of this is to use high calcium fly ash(HCFA) as a stimulant in blast furnace slag powder and use it as a cement substitute. As a result, it is judged that the substitution ratio of HCFA should be 15% or less. In addition, although durability and strength are relatively lower than of OPC, it is considered that it can be utilized as an environmentally building material.

Air-staging Effect for NOx Reduction in Circulating Fluidized Bed Combustion of Domestic Unused Biomass (국내 미이용 바이오매스 순환유동층 연소에서 NOx 저감을 위한 air-staging 효과)

  • Yoon, Sang-Hee;Beak, Geon-Uk;Moon, Ji-Hong;Jo, Sung-Ho;Park, Sung-Jin;Kim, Jae-Young;Seo, Myung-Won;Yoon, Sang-Jun;Yoon, Sung-Min;Lee, Jae-Goo;Kim, Joo-Sik;Mun, Tae-Young
    • Korean Chemical Engineering Research
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    • v.59 no.1
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    • pp.127-137
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    • 2021
  • Air emission charge for nitrogen oxide as a precursor of fine dust has been introduced and implemented within the country from 2020. Therefore, the development of economical combustion technology for NOx reduction has got more needed urgently. This study investigated the air-staging effect as a way to reduce the NOx during combustion of domestic unused forest biomass, recently possible to secure REC (Renewable Energy Certification) as a substitute for overseas wood pellets in a 0.1 MWth circulating fluidized bed combustion test-rig. Operating conditions were comparison with and without air-staging, the supply position of tertiary air (6.4 m, 8.1 m, 9.4 m in the combustor) and variation of air-staging ratio (Primary air:Secondary air:Tertiary air=91%:9%:0%, 82%:9%:9%, 73%:9%:18%). NO and CO concentrations in flue gas, profiles of temperature and pressure at the height of the combustion, unburned carbon in sampled fly ash and combustion efficiency on operating conditions were evaluated. As notable results, NO concentration with air-staging application under tertiary air supply at 9.4 m in the combustor reduced 100.7 ppm compared to 148.8 ppm without air-staging while, CO concentration increased from 52.2 ppm without air-staging to 99.8 ppm with air-staging. However, among air-staging runs, when tertiary air supply amount at 6.4 m in the combustor increased by air-staging ratio (Primary air:Secondary air:Tertiary air=73%:9%:18%), NO and CO concentrations decreased the lowest 90.8 ppm and 66.1 ppm, respectively. Furthermore, combustion efficiency at this condition was improved to 99.3%, higher than that (98.3%) of run without air-staging.

A Study on the Pozzolan Reactivity and Mechanical Characteristic of Blended Portland Cements using CFBC Fly Ash (순환유동층 플라이 애시를 사용한 혼합시멘트의 포졸란 반응성과 역학적 성질에 관한 연구)

  • Park, JongTak;Oh, Hongseob
    • Journal of the Korean Recycled Construction Resources Institute
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    • v.6 no.3
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    • pp.207-213
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    • 2018
  • Nowadays, circulating fluidized bed combustor(CFBC) boilers system that can reduce environmental pollution particles are widely used in electric power plants. But the fly ash generated from CFBC boilers has lower $SiO_2$ and higher MgO and $SO_3$ contents and also has free CaO inducing expansion and abrupt initial setting of concrete. Therefore, revised KSL5405 for CFBC fly-ash as well as pulverized coal combustion(PCC) is introduced in the concrete field. In this study, the chemical properties and mechanical properties of blended cements with PCC and CFBC fly-ash produced in Korea are analyzed. The blended cement with only CFBC fly ash shows a lower length change than OPC but a higher flow change ratio. The compressive strength of blended cement paste with PCC and CFBC fly ash is slightly greater than that of cement paste with only PCC fly-ash. Based on the results, CFBC flyash blended cement products should be used with PCC flyash to ensure the material stability and material properties.

Flow and Compressive Strength Properties of Low-Cement Soil Concrete (저시멘트 소일콘크리트의 유동성 및 압축강도 특성)

  • Park, Jong-Beom;Yang, Keun-Hyeok;Hwang, Chul-Sung
    • Journal of the Korean Recycled Construction Resources Institute
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    • v.6 no.1
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    • pp.1-7
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    • 2018
  • This study examined the effect of binder-to-soil ratio(B/S) and water-to-binder ratio(W/B) on the flow and compressive strength development of soil concrete using high-volume supplementary cementitious materials. As a partial replacement of ordinary portland cement, 10% by-pass dust, 40% ground granulated blast-furnace slag, and 25% circulating fluidized bed combustion fly ash were determined in the preliminary tests. Using the low-cement binder incorporated with clay soil or sandy soil, a total of 18 soil concrete mixtures was prepared. The flow of the soil concrete tended to increase with the increase in W/B and B/S, regardless of the type of soils. The compressive strength was commonly higher in sandy soil concrete than in clay soil concrete with the same mixture condition. Considering the high-workability and compressive strength development, it could be recommended for low-cement soil concrete to be mixed under the following condition: B/S of 0.35 and W/B of 175%.