新型回转窑窑头密封装置的应用

水泥企业现有回转窑窑头密封装置多数为密封罩包裹窑头,密封罩末端通过鱼鳞片或其他密封结构与窑筒体贴合密封,窑头的冷风套和吹风机被密封罩包裹起来。窑头的密封结构虽然一直在改进,但是密封效果依然不理想,飞扬出的砂石对工作人员的健康和环境造成极大的影响。除此之外,被包裹起来的冷风套中的冷风很难排出,在冷风的影响下,增加了回转窑煤耗的同时降低了燃烧效率,浪费资源,增加生产成本。     

水泥回转窑窑尾密封装置的改进

我公司２号窑为Φ３．５m／３．０m×５５m带流态化分解炉的回转窑，１９９４年底改造投产后，窑尾密封一直没有得到很好解决，困扰窑的正常生产。１改进前窑尾密封改进前窑尾靠活动密封圈前后移动进行密封，见图１，当窑体向上窜动时由动摩擦片推动静摩擦片使密封圈向上移动，当窑体向下窜动时由配重块拉动密封圈向下移动。但实际是，当配重重时，两摩擦片磨损严重，使用寿命短，当配重轻时，不能拉动密封圈向下移动，动作不灵，起不到密封效果。并且这种密封装置摩擦片间的摩擦力较大，也增大了窑的传动负荷。图１改进前密封装置２密封改…     

国内外回转窑密封技术的开发进展

介绍了回转窑及其对密封的要求,阐述了用于回转窑上的密封装置的类型、原理、特点及应用,总结了当前回转窑密封技术的开发进展及应用成果,分析了当前国内相比国外存在的差距,并指出了今后的发展方向。     

QD型回转窑窑尾密封装置

0前言回转窑进料端处的密封,对于新型干法回转窑系统的正常运转是非常重要的。其主要作用是尽可能减少冷空气吸入窑内及防止漏灰,因为吸人冷空气会增加窑的废气量、增加分解炉的燃料损耗、增大排风机的负荷和引起窑尾结皮堵塞,而漏庆会造成环境污染。随着科学技术的不断进步和发展,国内外均研制出了种类繁多的密封方法和装置,归纳起来大体可分为摩擦式、迷宫式（曲径式）、气密式和组合式等几种型式。设计一个结构简单、操作可靠、维护方便的窑尾密封装置,涉及的因素很多也很复杂。对于一个良好的密封装置至少应满足结构简单,安装维…     

回转窑窑尾密封装置的改造

我厂1号窑于198o年11月建成投产，属60年代生产技术。立筒预热器为单列五钵的克努伯型预热器，原设计窑型为：rp4／4．4nlX60m，后于1993年改为di4nlX60m窑。由于该预热器顶部四个旋风筒的排灰阀卸灰是间断性的和在钵体内各缩口处堆积的物料不均匀地滑落，从而易产生“塌料”现象；又由于窑尾热风机排风能力限制，不足以在立筒及窑内形成持续稳定的负压，因此偶尔会出现倒风。于是在窑尾产生了热物料与气体的混合物喷出，其温度高达900℃左右，极易造成密封装置部件的损坏，产生泄漏，影响生产的正常进行。为此，我厂对窑尾密封装置进行了…     

湿法回转窑窑尾密封装置的改进

1问题我矿水泥厂3条Φ3.0m/2.5m×90m湿法回转窑于1977年投产,窑体与窑尾冷烟室的联接如图1所示。窑体上下窜动时,窑尾密封装置的活动套在重锤的作用下,沿着窑体的中心线前后摆动,使两摩擦圈紧密接触而起密封作用。图1回转窑窑尾密封装置示意图经过近20年的生产,由于设备老化,窑尾两密封圈之间产生了一条间隙,冷风进入冷烟室,影响窑的热工制度。当操作工发现窑尾密封装置进冷风时,通常的处理方法就是用钢钎将和静摩擦圈相连的活动套移出来,使静摩擦圈与动摩擦圈尽可能合拢。该法费时费力。由于窑体上下不停窜动,这种操作每班就得4～5次。我…     

回转窑窑头密封装置的改造

1 问题的提出 我公司回转窑为Φ3.95×56m窑外分解窑,窑头密封装置采用钢丝绳压紧弹性片径向接触式密封形式(弹性片材质为1Cr18Ni9Ti),见图1。自1995年6月点火投产以来,密封效果一直不好,正压严重。密封不好,则外部冷空气进入窑内,使窑内的物料量、燃料量和空气量的一定比例关系遭到破坏,减     

利用电厂干法脱硫灰生产硫铝酸钙改性硅酸盐水泥

我公司有一条1500t/d硫铝酸钙改性硅酸盐水泥生产线,采用石灰石、铝尾矿、砂岩和粉煤灰等配料。2015年初公司开始使用附近的电厂干法脱硫灰用于生料配料中,使生料产量增加了20%,取得了良好的效果。     

2000tpd生产线高固气比煅烧技术改造

我公司2　000t/d生产线于2003年11月建成投产,投产后一直存在产量较低、煤耗过高、生产成本高等问题。2014年10月,我公司委托陕西德龙水泥高新技术孵化有限公司,应用“XDL高固气比水泥熟料煅烧新工艺”对烧成系统进行技术改造。改造后,熟料产量增加24.7%,熟料标准煤耗降低23%,电耗降低8%,SO2和NOx排放量明显降低。     

A Parametric approach to testing the null of cointegration

A residual-based test for cointegration is proposed where a parametric adjustment is made to account for the possible stationarity of the disturbance vector. Allowance is also made for the regressor variables to be cointegrated among themselves. The parametric adjustment turns out to be more robust and powerful than tests based on long-run variance estimators according to theoretical and simulation evidence.     

Test for the null hypothesis of cointegration with reduced size distortion

Abstract. This article considers a single‐equation cointegrating model and proposes the locally best invariant and unbiased (LBIU) test for the null hypothesis of cointegration. We derive the local asymptotic power functions and compare them with the standard residual‐based test, and show that the LBIU test is more powerful in a wide range of local alternatives. Then, we conduct a Monte Carlo simulation to investigate the finite sample properties of the tests and show that the LBIU test outperforms the residual‐based test in terms of both size and power. The advantage of the LBIU test is particularly patent when the error is highly autocorrelated. Furthermore, we point out that finite sample performance of existing tests is largely affected by the initial value condition while our tests are immune to it. We propose a simple transformation of data that resolves the problem in the existing tests.     

Flavor and oxidative stability of oil processed from null lipoxygenase-1 soybeans

The role played by lipoxygenase in the flavor quality of soybean oil was investigated by comparing the oil processed from special soybeans lacking lipoxygenase-1 (Forrest x P.I. 408251) with the oil from normal (Century) beans. Quality assessment was based on sensory evaluations and on capillary gas chromatographic (GC) analyses of volatiles of the extracted crude, partially processed, and refined, bleached and deodorized oils. In direct comparisons of oil products from the two types of beans, no significant differences were found in either flavor quality or in flavor stability based on total volatiles, and in analyses for 2,4-decadienal. Although thermal tempering did not significantly affect the initial flavor scores of crude and degummed oils from Century and low L-1 soybeans, the initial scores of refined and bleached oils from Century soybeans were significantly improved by this treatment. Similarly, thermal tempering was just as important in producing good quality flour from the special beans lacking lipoxygenase-1 as the flour from normal beans. Therefore, factors other than lipoxygenase-1 appear to affect the food quality of soybean oils and meals.     

Measuring the thermal conductivity of residue-free suspended graphene bridge using null point scanning thermal microscopy

Despite the importance of the accurate measurement of the thermal conductivity of graphene, deviations in previous data are still quite large due to the low signal-to-noise ratio in the measurement of graphene temperature, the uncertainties in the measurement of the heat dissipation, and the influence of the polymeric residues. Herein, we improve signal-to-noise ratio by using null point scanning thermal microscopy, which profiles temperature quantitatively with nanoscale spatial resolution (∼50 nm), independently of both the heat flux through the air and the variation of the sample surface properties. Also, we control and monitor the heat generation rate accurately by heating the suspended graphene bridge electrically. Furthermore, we prevent the disturbance of the thermal conductivity caused by the polymeric residues by using polydimethylsiloxane stamping method, which leaves much less residue than using polymethylmethacrylate. The thermal conductivity values of graphene, whose length and width are 3.6 and 5.52 μm, respectively, were measured as 2430 ± 190, 2150 ± 170, and 2100 ± 160 W/mK at the peak temperatures of 335, 361, and 366 K, respectively, with much smaller error range compared to the previously reported values. The measured values exceed the highest value (∼2000 W/mK at room temperature) obtained for graphite.     

Compared imbibitions of ordinary and high performance concrete with null or positive water pressure head

A method to simultaneously measure the moisture diffusion coefficient, D_θ, of unsaturated concrete, and the saturated concrete hydraulic conductivity, K_l, was developed for cylindrical specimens placed on a container filled with water that could be maintained at a given hydraulic pressure. Ordinary Portland cement Concrete (OPC) with a moderate and High Performance Concrete (HPC) with a low water to cement ratio were tested. The time dependent distribution of water content in the specimens was measured using a non-intrusive method based on gamma-ray attenuation. The measurements were conducted with varying hydraulic head (positive or null). Boltzmann's transformation was used to analyze the experimental results obtained at different hydraulic pressures and the difference between the null (or atmospheric) and positive pressure results is used to accurately determine K_l and also D_θ . This paper will present the results obtained using this original method, possible interpretations and future research.     

Residuals‐based tests for the null of no‐cointegration: an Analytical comparison

Abstract. This article studies the asymptotic distribution of five residuals‐based tests for the null of no‐cointegration under a local alternative when the tests are computed using both ordinary least squares (OLS) and generalized least squares (GLS)‐detrended variables. The local asymptotic power of the tests is shown to be a function of Brownian motion and Ornstein–Uhlenbeck processes, depending on a single nuisance parameter, which is determined by the correlation at frequency zero of the errors of the cointegration regression with the shocks to the right‐hand side variables. The tests are compared in terms of power in large and small samples. It is shown that, while no significant improvement can be achieved by using unit root tests other than the OLS detrended t‐test originally proposed by Engle and Granger (1987), the power of GLS residuals tests can be higher than the power of system tests for some values of the nuisance parameter.     

Long-chain fatty acid uptake by skeletal muscle is impaired in homozygous,but not heterozygous,heart-type-FABP null mice

Previous studies with cardiac myocytes from homozygous heart-type fatty acid (FA)-binding protein (H-FABP)^−/− mice have indicated that this intracellular: receptor protein for long-chain FA is involved in the cellular uptake of these substrates. Based on the knowledge that muscle FA uptake is a process highly sensitive to regulation by hormonal and mechanical stimuli, we studied whether H-FABP would play a role in this regulation. A suitable model system to answer this question is provided by H-FABP^+/− mice, because in hindlimb muscles the content of H-FABP was measured to be 34% compared to wild-type mice. In these H-FABP^+/− skeletal muscles, just as in H-FABP^−/− muscles, contents of FA transporters, i.e., 43-kDa FABPpm and 88-kDa FAT/CD36, were similar compared to wild-type muscles, excluding possible compensatory mech-anisms at the sarcolemmal level. Palmitate uptake rates were measured in giant vesicles prepared from hindlimb muscles of H-FABP^−/−, H-FABP^+/− and H-FABP^+/+ mice. For comparison, giant vesicles were isolated from liver, the tissue of which expresses a distinct type of FABP (i.e., L-FABP). Whereas in H-FABP^−/− skeletal muscle FA uptake was reduced by 42–45%, FA uptake by H-FABP^+/− skeletal muscle was not different from that in wild-type mice. In contrast, in liver from H-FABP^−/− and from H-FABP^+/− mice, FA uptake was not altered compared to wild-type animals, indicating that changes in FA uptake are restricted to H-FABP expressing tissues. It is concluded that H-FABP plays an important, yet merely permissive, role in FA uptake into muscle tissues.