To provide basic data for the reasonable mixing design of the alkali-activated (AA) foamed concrete as a thermal insulation material for a floor heating system, 9 concrete mixes with a targeted dry density less than 4...To provide basic data for the reasonable mixing design of the alkali-activated (AA) foamed concrete as a thermal insulation material for a floor heating system, 9 concrete mixes with a targeted dry density less than 400 kg/m3 were tested. Ground granulated blast-furnace slag (GGBS) as a source material was activated by the following two types of alkali activators: 10% Ca(OH)2 and 4% Mg(NO3)2, and 2.5% Ca(OH)2 and 6.5% Na2SiO3. The main test parameters were water-to-binder (W/B) ratio and the substitution level (RFA) of fly ash (FA) for GGBS. Test results revealed that the dry density of AA GGBS foamed concrete was independent of the W/B ratio an RFA, whereas the compressive strength increased with the decrease in W/B ratio and with the increase in RFA up to 15%, beyond which it decreased. With the increase in the W/B ratio, the amount of macro capillaries and artificial air pores increased, which resulted in the decrease of compressive strength. The magnitude of the environmental loads of the AA GGBS foamed concrete is independent of the W/B ratio and RFA. The largest reduction percentage was found in the photochemical oxidation potential, being more than 99%. The reduction percentage was 87% - 93% for the global warming potential, 81% - 84% for abiotic depletion, 79% - 84% for acidification potential, 77% - 85% for eutrophication potential, and 73% - 83% for human toxicity potential. Ultimately, this study proved that the developed AA GGBS foamed concrete has a considerable promise as a sustainable construction material for nonstructural element.展开更多
Replacing heavy oil with petrol coke can greatly reduce the cost of glass production,but obviously shorten the service life of refractories used in the regenerator checker body of glass tanks.To prolong the service li...Replacing heavy oil with petrol coke can greatly reduce the cost of glass production,but obviously shorten the service life of refractories used in the regenerator checker body of glass tanks.To prolong the service life of the regenerator checker body,the slag chemical composition and alkali-sulfur ratio of glass tanks after using petrol coke and the damage mechanism of the residual magnesia bricks in the regenerator checker body were studied,as well as the corrosion resistance of three magnesia based bricks(direct bonded magnesia chrome bricks,fused rebonded magnesia chrome bricks,and fused rebonded high-purity magnesium aluminate spinel bricks).On this basis,a series of targeted countermeasures were adopted to optimize the configuration of refractories,significantly improving the service life of checker bricks and meeting the requirements of glass industry development.展开更多
气化炉灰渣比(合成气携带走的飞灰与沉积至壁面的熔渣的质量比)是影响后续合成气净化设备寿命的关键因素,优化烧嘴偏转角度是控制气化炉灰渣比的有效方法。采用数值模拟方法,研究了HNCERI(Huaneng Clean Energy Research Institute)气...气化炉灰渣比(合成气携带走的飞灰与沉积至壁面的熔渣的质量比)是影响后续合成气净化设备寿命的关键因素,优化烧嘴偏转角度是控制气化炉灰渣比的有效方法。采用数值模拟方法,研究了HNCERI(Huaneng Clean Energy Research Institute)气化炉一段四烧嘴偏转角度对气化炉灰渣比、壁面渣层及耐火材料的影响。数值模拟结果表明,烧嘴偏转角度由0°增加至4.5°,灰渣比由2.0降低至0.8,液态渣层平均停留时间减少31.5%。偏转角度增加,渣口位置液/固态渣层厚度均增加;H=4.45~5.07 m位置固态渣层厚度下降,液态渣层厚度则增加。液态渣层流速与黏度呈负相关,与厚度呈正相关,液态渣层厚度主要受流速和颗粒沉积率影响。偏转角度增加,烧嘴平面上方耐火材料表面平均温度升高,烧嘴平面下方耐火材料表面平均温度降低,偏转角度为3.5°时耐火材料需要承受的最高温度取得最低值。在有效降低灰渣比前提下,为减少气化炉堵渣、渣层脱落和耐火材料烧蚀概率,HNCERI气化炉烧嘴偏转角度建议取3.5°。展开更多
文摘To provide basic data for the reasonable mixing design of the alkali-activated (AA) foamed concrete as a thermal insulation material for a floor heating system, 9 concrete mixes with a targeted dry density less than 400 kg/m3 were tested. Ground granulated blast-furnace slag (GGBS) as a source material was activated by the following two types of alkali activators: 10% Ca(OH)2 and 4% Mg(NO3)2, and 2.5% Ca(OH)2 and 6.5% Na2SiO3. The main test parameters were water-to-binder (W/B) ratio and the substitution level (RFA) of fly ash (FA) for GGBS. Test results revealed that the dry density of AA GGBS foamed concrete was independent of the W/B ratio an RFA, whereas the compressive strength increased with the decrease in W/B ratio and with the increase in RFA up to 15%, beyond which it decreased. With the increase in the W/B ratio, the amount of macro capillaries and artificial air pores increased, which resulted in the decrease of compressive strength. The magnitude of the environmental loads of the AA GGBS foamed concrete is independent of the W/B ratio and RFA. The largest reduction percentage was found in the photochemical oxidation potential, being more than 99%. The reduction percentage was 87% - 93% for the global warming potential, 81% - 84% for abiotic depletion, 79% - 84% for acidification potential, 77% - 85% for eutrophication potential, and 73% - 83% for human toxicity potential. Ultimately, this study proved that the developed AA GGBS foamed concrete has a considerable promise as a sustainable construction material for nonstructural element.
文摘Replacing heavy oil with petrol coke can greatly reduce the cost of glass production,but obviously shorten the service life of refractories used in the regenerator checker body of glass tanks.To prolong the service life of the regenerator checker body,the slag chemical composition and alkali-sulfur ratio of glass tanks after using petrol coke and the damage mechanism of the residual magnesia bricks in the regenerator checker body were studied,as well as the corrosion resistance of three magnesia based bricks(direct bonded magnesia chrome bricks,fused rebonded magnesia chrome bricks,and fused rebonded high-purity magnesium aluminate spinel bricks).On this basis,a series of targeted countermeasures were adopted to optimize the configuration of refractories,significantly improving the service life of checker bricks and meeting the requirements of glass industry development.
文摘气化炉灰渣比(合成气携带走的飞灰与沉积至壁面的熔渣的质量比)是影响后续合成气净化设备寿命的关键因素,优化烧嘴偏转角度是控制气化炉灰渣比的有效方法。采用数值模拟方法,研究了HNCERI(Huaneng Clean Energy Research Institute)气化炉一段四烧嘴偏转角度对气化炉灰渣比、壁面渣层及耐火材料的影响。数值模拟结果表明,烧嘴偏转角度由0°增加至4.5°,灰渣比由2.0降低至0.8,液态渣层平均停留时间减少31.5%。偏转角度增加,渣口位置液/固态渣层厚度均增加;H=4.45~5.07 m位置固态渣层厚度下降,液态渣层厚度则增加。液态渣层流速与黏度呈负相关,与厚度呈正相关,液态渣层厚度主要受流速和颗粒沉积率影响。偏转角度增加,烧嘴平面上方耐火材料表面平均温度升高,烧嘴平面下方耐火材料表面平均温度降低,偏转角度为3.5°时耐火材料需要承受的最高温度取得最低值。在有效降低灰渣比前提下,为减少气化炉堵渣、渣层脱落和耐火材料烧蚀概率,HNCERI气化炉烧嘴偏转角度建议取3.5°。
