复掺偏高岭土对混凝土抗压强度的影响

我国高岭土资源丰富,偏高岭土应用于混凝土有将会很大前景。本文对比研究了复掺偏高岭土对混凝土抗压强度的影响。研究表明在水胶比为0．31下,偏高岭土与粉煤灰总掺量为35％（偏高岭土掺量为8％）时更能充分发挥偏高岭土的活性。合理的偏高岭土掺入对掺粉煤灰混凝土早期抗压强度有提高明显,抗压强度提高可达47％。     

厨房通风设计中风机风量与风压的确定

介绍了厨房排风量确定的几种方法;讨论了在厨房通风系统设计中对风量和压力影响比较大而又经常不被注意的几个问题,如烟囱效应、风机压力有效性等;并介绍了厨房排风用风机的选型。     

Property investigation of individual phases in cementitious composites containing silica fume and fly ash

In this study, nanoindentation was used to investigate the microstructures of cementitious composites containing silica fume and fly ash. With the help of scanning electron microscope, the mechanical properties (elastic modulus and hardness) of individual phases (like outer product, inner product, calcium hydroxide, remained fly ash particles, residual cement grains) in cementitious composites containing silica fume and fly ash were investigated and analyzed. Additionally, this study examined the differences between the ‘C–S–H’ phases in the different cementitious composites and provided an insight into the influence of mineral admixtures (silica fume and fly ash) on the properties of the ‘C–S–H’ phase.     

Prediction of long-term chloride diffusion in silica fume concrete in a marine environment

Chloride-induced corrosion is the main factor in determining the durability and service life of the reinforced concrete structures exposed to marine environments. Recognition of chloride diffusion phenomenon in concrete and developing a prediction model that can estimate the service life of the concrete structures subject to long-term exposure is vital for aggressive marine environments. The present study focuses on developing such a prediction model of chloride diffusion coefficient for silica fume concrete under long-term exposure to a durability site located in the southern region of Iran. All investigations are based on 16 concrete mix designs containing silica fume with variable water-to-binder ratios exposed to sea water for maximum period of 60 months. This empirical model is developed by applying regression analysis based on Fick’s second law on the experimental results and is compared with previous studies in this area. This comparison indicates that the predicted chloride diffusion coefficient level is within a ±25% error margin in the specimens. The results indicate that reducing the water-to-binder ratio and adding the silica fume to a dosage of 10% reduces the chloride diffusion coefficient in concrete. This study also confirms that the chloride diffusion coefficient increases with temperature and decreases over time.     

催化汽油加氢精制加氢异构化工艺

为了降低催化汽油中的烯烃含量、硫含量，进行了催化汽油加氢精制加氢异构化的研究。结果表明．采用KT加氢异构化催化剂，通过加氢精制加氢异构化反应，液体产品收率在99％以上，脱硫率在80％以上，汽油的硫含量降到了50μg/g以下，汽油烯烃含量降低了7．25％，辛烷值损失0．8。     

湿法脱硫装置的设备与管道的腐蚀及对策

在目前国内已投运的湿法脱硫装置中 ,设备及管道的腐蚀问题未得到很好解决 ,影响了脱硫装置的可用率。主要腐蚀现象包括 :缝隙腐蚀 ;点腐蚀 ;应力开裂腐蚀 ;气泡腐蚀和冲刷腐蚀等。腐蚀环境包括烟气换热器、烟道、吸收塔等烟气流经之处。可采用耐蚀金属材料、橡胶内衬、玻璃鳞片树脂内衬、其他非金属材料来防腐蚀。     

影响湿式氧化法脱硫塔堵塞若干问题的讨论

把脱硫塔堵塞形态作为研究问题的切入点 ,指出吸收过程和再生过程中存在的诸如空速、喷淋量、原料气中 O2 含量及氧化槽液位控制不当等问题 ,提出了改进流程和分段吸收的构想。     

CFB锅炉燃烧福建无烟煤的工业性试验

用石灰石做脱硫剂,在一台35 t/h循环流化床(CFB)锅炉上进行工业试验.采用炉内添加石灰石混烧的脱硫工艺,测试钙硫比和石灰石颗粒径变化对脱硫及锅炉运行效果的影响.试验结果表明(1)时均脱硫效率与瞬态最高脱硫效率均随Ca/S比的增加而增大,但在Ca/S＜2.5时增加缓慢.当Ca/S摩尔比为3.15时,时均脱硫效率有53.5%,瞬态最高脱硫效率可达77%;(2)石灰石的平均颗粒径越细,脱硫效率越高.当平均颗粒径为0.36 mm时,时均脱硫效率接近于50%;(3)加入石灰石脱硫会引起炉床温度波动,但波动幅度不大.当钙硫比较小时,炉床温度先升后降;而在钙硫比较大情况下,炉床温度则是先降后升;(4)在Ca/S比较小的情况下,添加石灰石混烧会使锅炉炉床平均温度下降,而使炉膛中部、上部和出口处的温度上升;在高Ca/S比情况下(＞3.0)却使锅炉整体的运行温度都下降.从试验结果推断,当钙硫比取2.5～3.0,石灰石平均粒径取0.2 mm～1.0 mm时,可以得到较好的脱硫运行效果.     

大孔磺酸树脂固载AlCl3用于噻吩与烯烃的烷基化反应

大孔磺酸树脂固载AlCl3是提高树脂催化剂酸强度及其烷基化活性的有效方法,本工作以NKC9, CT175两种磺酸树脂催化剂为载体,采用AlCl3气相固载法分别于不同固载温度及固载时间条件下制得AlCl3–NKC9, AlCl3–CT175催化剂,并对其用于噻吩与异丁烯、异戊烯的烷基化反应活性进行了考察. 结果表明：在固载时间为10~25 h、固载温度为110~120℃条件下,所制得的催化剂在常压、温度60℃、原料(含4300 mg/L噻吩的苯溶液)质量空速为7.5 h–1的反应条件下具有很高的噻吩烷基化活性(噻吩转化率达95%),且固载AlCl3后的树脂催化剂活性稳定性较固载前有较大程度提高.     

稻壳灰对高强超高强混凝土钢筋粘结强度的影响

对掺有稻壳灰和硅灰、强度在 3 0～ 10 0MPa的混凝土 -钢筋粘结强度进行了试验 ,分析讨论了稻壳灰等高硅火山灰材料对混凝土 -钢筋粘结强度的影响。研究结果表明 ,高硅掺合料是一个独立于混凝土强度之外、对钢筋粘结强度有重要影响的因素 ,掺加高硅掺合料比提高混凝土强度能更有效地提高钢筋粘结强度。建议在计算钢筋锚固长度时应该考虑高硅掺合料这一因素