危废处理回转窑的砌筑与烘炉技术探讨

回转窑是危险废物处理最为有效的设备,在国内的应用越来越广泛.回转窑中耐火材料的质量影响了回转窑能否稳定运行.对危险废物处理回转窑耐火材料的选用、砌筑和烘炉进行了分析,对工程应用具有一定的参考价值.     

几种工业炉,烟囱的烘烤曲线

一、工业炉的烘炉制度 1.烘炉周期工业炉在砌筑完毕后投入生产前,必须进行烘干及加热。各种炉型的烘干及加热时间应根据炉子容积大小、用途、砖质、施工季节、砌筑后风干的时间长短等因素而定。烘炉时可参照表1所规定的时间范围进行。     

日产900 t活性石灰回转窑砌筑介绍

介绍了鲅鱼圈日产900t活性石灰回转窑各部位结构特点、砌筑所需要的耐火材料及施工方法。提出了回转窑冬季砌筑施工中应注意的问题及产生质量问题的处理方法。     

回转窑砌筑工艺及质量控制

主要介绍了回转窑的结构,叙述了回转窑砌筑施工准备及其施工方法,及施工产生的质量问题产生的原因及处理技术。     

RKEF工艺回转窑砌筑施工技术研究

以缅甸达贡山镍矿项目2台Φ5.5m×115mRKEF工艺镍铁回转窑为例对窑炉砌筑进行细致分析,特别对窑体重要部位内衬的施工方法进行了详细描述。同时介绍了镍铁回转窑砌筑过程、工艺,以及质量控制方法。     

干熄焦炉砌筑工艺

本文主要介绍了焦炉附属设备、干熄焦炉及一次除尘内衬结构,叙述了回转窑砌筑施工准备、施工顺序、施工工艺以及施工中的质量控制方法及处理技术。     

直接还原铁回转窑耐火材料的选配、设计与施工

简述在某直接还原铁项目中回转窑的耐火材料选配、设计和施工中的要点,说明此类窑采用干法砌筑的可行性。     

八钢C高炉热风炉冬季保温技术研究与实践

八钢C高炉热风炉在冬季前施工完毕,很多外部条件不具备正常烘炉,为保证热风炉刚砌筑完的耐材质量,提出了一种新的防冻保温方案和采取一系列临时措施,热风炉内部采用了低温烘炉,烟气从冷风管道经倒流休风管排放,同时热风炉外部采用纤维毯保温措施,保证了热风炉炉壳整个冬季的温度控制在零度以上,为以后冬季施工的热风炉工程提出了新的保温方法。     

大型球团带式焙烧机耐火材料设计与优化

介绍了大型球团带式焙烧机耐火材料的设计与优化,阐述了功能化、长寿化、节能化新型耐火材料的应用,重点说明了耐火材料内衬综合砌筑设计与优化,同时介绍大型带式烧结机耐火材料施工与烘炉.     

大型焦炉砌筑中存在问题及处理措施

近些年焦炉砌筑所用耐火材料主要以硅砖为主。在焦炉砌筑及烘炉过程中,由于砌筑原因会造成炉体窜漏,导致炉体耗热量大,以及一些砌筑缺陷无法弥补。文中简要介绍了焦炉砌筑中避免发生的错误,为今后焦炉炉体砌筑提供参考。     

Nondestructive Testing Evaluation of Drying Process in Flooded Full-Scale Masonry Walls

After an investigation on the most recent floods occurred in Italy that damaged the Cultural Heritage masonry buildings, an experimental research started on-site on full-scale masonry models exposed to the environmental agents in Milan. The masonry materials used for the full-scale models were largely investigated in the past and the models were subjected to decay caused by the capillary rise and by the crystallization of sodium sulfate coming from the foundations. These walls can actually simulate the state of naturally contaminated walls before a flood and represent a construction where the main parameters are known. A flood has been simulated by adding water for several days to the walls of the full-scale models previously contaminated by salts, then the walls were left to naturally dry. The objective is to check the effectiveness of nondestructive (ND) techniques in detecting the presence of water and the drying process and also the influence of surface treatments presence. Radar tests, thermography tests, sonic tests, as well as the minor destructive powder drilling tests were applied successfully to evaluate the moisture distribution in the masonry after flooding and during natural drying.     

使用复合炉底延长中低碳铬铁炉衬寿命的探讨

在中低碳铬铁电炉中使用复合炉底,通过对极心圆直径、炉壳直径、二次电压、炉渣碱度及捣打料对炉底影响的分析,以及对抗高温理论、砌筑工艺、烘炉制度的探讨,总结出了有效延长炉衬寿命的方法。     

关于硅砖内部裂纹的探讨

在筑炉前,对硅砖进行切、磨时,有时发现砖的内部有裂纹。这种裂纹不是成型时产生的层裂,而是在烧成过程中预热阶段升温过快、砖坯内外温差大,使砖坯膨胀不一致而产生热应力所致。防止的措施:强化干燥作业、调整热工制度和对隧道窑进行改造。     

Radon penetration of concrete slab cracks, joints, pipe penetrations, and sealants

Radon movement through 12 test slabs with different cracks, pipe penetrations, cold joints, masonry blocks, sealants, and tensile stresses characterized the importance of these anomalous structural domains. Diffusive and advective radon transport were measured with steady-state air pressure differences controlled throughout the deltaP = 0 to 60 Pa range. Diffusion coefficients (deltaP = 0) initially averaged 6.5 x 10(-8) m2 s(-1) among nine slabs with only 8% standard deviation, but increased due to drying by 0.16% per day over a 2-y period to an average of 2.0 x 10(-7) m2 s(-1). An asphalt coating reduced diffusion sixfold but an acrylic surface sealant had no effect. Diffusion was 42 times higher in solid masonry blocks than in concrete and was not affected by small cracks. Advective transport (deltaP < or = 60 Pa) was negligible for the slabs (10(-16) m2 permeability), pipe penetrations, and caulked gaps, but was significant for cracks, disturbed pipe penetrations, cold joints, masonry blocks, and concrete under tensile stress. Crack areas calculated to be as small as 10(-7) m2 significantly increased radon advection. Algebraic expressions predict air velocity and effective crack width from enhanced radon transport and air pressures. Masonry blocks, open cracks, and slab cold joints enhance radon penetration but stressed slabs, undisturbed pipe penetrations, and sealed cracks may not.     

高炉炉缸炭砖砌筑结构的传热学

 从传热学角度通过建立炉缸传热数学模型,分别对大块炭砖的炉缸结构和小块炭砖的炉缸结构进行了讨论。计算了它们在烘炉阶段和高炉开炉后炉缸砖衬的温度,发现了按照目前的烘炉规范进行烘炉,难以将炭砖与冷却壁间的填料烘干,填料的导热系数达不到设计值。填料的存在导致砖衬热面温度升高,致使砖衬侵蚀加剧。因此,在冷却壁与炭砖之间取消填料,让炭砖直接顶砌冷却壁具有明显的传热优势。对于使用小块炭砖的炉缸,可以直接将炭砖顶砌冷却壁,消灭填料对炉缸传热的限制影响;对于大块炭砖结构的炉缸,先采用部分小块炭砖顶砌冷却壁,在小块与大块炭砖间使用填料,将填料向高炉内部推移约200mm以上,烘炉阶段为了将填料烘干,冷却壁断水烘炉是必需的,为了保证冷却壁的安全,同时讨论了冷却壁断水烘炉应注意的问题。     

Development and Performance Evaluation of Interlocking-Block Masonry

Accelerated mortarless masonry constructions have been developed or are being used in different countries with limited research studies. This paper discusses first the salient features of interlocking-block masonry and then the development of simple interlocking-concrete-block masonry systems, keeping in view the requirements of shape simplicity and ease of manufacture. Testing of wallettes under axial compression, eccentric compression (e∕t ratios of 0, t/6, and t/3), and flexural loading parallel and perpendicular to bed joints were carried out on dry-stacked specimens. Interlocking-block masonry results in relatively high efficiency factors in axial compression and eccentric-to-axial capacity ratio when compared with mortar bedded masonry. Unlike conventional masonry, the flexural capacity of interlocking-block masonry normal to the bed joint is higher than that parallel to the bed joint. A better interlocking mechanism of channel-shaped interlocking blocks, as compared to I-shaped blocks, leads to a relatively higher flexural capacity of the former.     

Lateral Out-of-Plane Strengthening of Masonry Walls with Composite Materials

The structural behavior of masonry walls laterally strengthened with externally bonded composite materials to resist out-of-plane loads is theoretically and experimentally studied. Hollow concrete block masonry walls and solid autoclaved aerated concrete (AAC) block masonry walls are examined. A theoretical model that accounts for the cracking and the physical nonlinear behavior, the debonding of the composite layers, the arching effect, the interfacial stresses, and the unique modeling aspects of the laterally strengthened wall is presented. The experimental study includes loading to failure of 4 laterally strengthened masonry walls and 2 control walls. The experimental and analytical results point at the unique aspects of the lateral strengthening of masonry walls with composite materials. In particular, they reveal and explain the premature shear failure in laterally strengthened hollow concrete blocks walls and, on the other hand, demonstrate the potential of lateral fiber-reinforced polymer strengthening of AAC masonry walls. The laterally strengthened AAC masonry walls reveal improved strength, deformability, and integrity at failure characteristics.     

Analytical Investigation of Lateral Strength of Masonry Infilled RC Frames Retrofitted with CFRP

In this study, two reinforced concrete frames with hollow clay tile masonry infill walls, retrofitted with diagonally applied carbon fiber-reinforced polymer (CFRP), which were tested previously, were analytically investigated. A simple material model for the masonry infill wall strengthened with CFRP is suggested. The lateral strength of each rehabilitated frame was obtained by pushover analysis of four different models using a commercially available finite-element program, and the results were compared with the test results. We also determined the lateral strength of the CFRP-applied masonry infill walls, and compared the results with the results obtained from existing analytical models. Drift capacity of the masonry infill walls strengthened with CFRP was also investigated, and the drift capacity of the masonry infill walls strengthened with diagonally applied CFRP was recommended. It is concluded that the strength of the masonry infilled frames strengthened with diagonally applied CFRP can be satisfactorily predicted with the suggested procedure. The ultimate drift capacity of the masonry infill walls strengthened with diagonally applied CFRP strips was conservatively predicted to be 1.0%.     

Flexural Behavior of GFRP-Reinforced Concrete Masonry Beams

An experimental and analytical study is conducted in order to investigate the flexural behavior of masonry beams that are internally reinforced using glass fiber-reinforced polymers (GFRP) rebars. Seven reinforced masonry beams with 4.0- and 2.4-m spans were tested under four-point bending setup. The beams were loaded monotonically up to failure. One had two courses of hollow concrete masonry units and the remaining six beams had three courses. Two masonry beams were reinforced using conventional steel rebars and were considered as the control specimens. The remaining five beams were internally reinforced using GFRP rods with different reinforcement ratios. Beams were detailed to have sufficient shear reinforcement such that they do not fail in shear. Flexural capacity, deformation, curvature, and strains of the tested GFRP-reinforced and steel-reinforced masonry beams were compared and discussed. Using the acquired data from the experimental and analytical studies, effectiveness of GFRP rods as internal reinforcement for concrete masonry beams is demonstrated.     

Assessment of Multispan Masonry Arch Bridges. II: Examples and Applications

Modern approaches to multispan masonry bridges are approximate in many ways: load distribution, masonry degradation, fill-to-barrel, span-to-span, and span-to-pier interaction are taken into account by means of approximate models or are neglected. At the end of the assessment procedure, the approximation to the load carrying capacity of the bridge cannot be easily quantified. In Part I of this paper, an extension of the classical approach to masonry arches was formulated taking into account the nonlinear response of masonry, a limit to compressive inelastic strains, and assuming simplifying but conservative assumptions. The procedure allows the analysis of multispan masonry bridges considering the nonlinear response of arches and barrels and the mutual interaction. The response of two- and three-span prototypes is compared to that of a single arch; then the procedure is applied to a six- 18.5-m span in-service viaduct. A detailed comparison with the single-span-bridge approach is discussed. Specific attention is paid to the evolution of the collapse mechanism and to the effect of load distribution, addressing the concentrated loads versus distributed equivalent loads problem and showing how the limit to compressive inelastic strains, i.e., to masonry ductility, may be of great importance to the structural analysis of masonry bridges.