高原型1000t／d预分解窑的操作体会

我厂窑尾预分解系统采用带有第三代 RSP分解炉型预热器,预分解区总有效容积达 347. 7m3。三次风以双切线方式将生料载入 SC室,产生强烈的涡旋运动 ,既延长了气固停留时间,也使物料形成了边壁浓中心稀的吸热保护屏障,炉衬寿命大大延长,分解室耐火砖自 1995年 7月投产以来未更换过,入窑物料分解率稳定在 90％～ 93％, RSP炉出口燃料燃尽率达 95％～ 96％,极少出现“后燃”现象。生产实践表明,高海拔地区窑操作的重点应是窑速和风量控制。笔者结合实际浅谈几点操作体会。 1窑及单筒冷却机的合理操作 1. 1窑速控制 　　主要是控制…     

带余热锅炉的流态化预分解窑系统的问题分析及改进

０引言呼和浩特市水泥厂２号窑为带余热锅炉的流态化预分解窑，回转窑规格为Φ３．５m／３．０m×５７m，汽轮机装机容量６０００kW。该系统自运行以来，流态化分解炉因喂料点偏低，供料能力差，分解率低，以及频繁的后结圈一直困扰着回转窑的正常生产，给企业带来了极大的影响。１窑系统工艺流程系统工艺流程见图１。图１窑系统工艺流程生料首先入分解炉，分解炉类似于MFC型，在炉内生料随８８０～９００℃热气流上升进入到C１筒内。C１筒收集下的物料入窑，含尘气流进入到C２筒继续进行气固分离，收集下的物料入窑，废气进入到余热锅炉…     

分解炉的不良安装对熟料烧成的影响及改进措施

我公司2 500 t/d预分解窑水泥生产线,采用规格为Φ5 m×33．73 m的NC-SST-I型分解炉。受建设时技术水平所限,在生产中暴露出一些问题,如:入窑生料分解率偏低,窑产、质量一直不理想;分解炉结皮厚重,影响窑内通风,甚至停窑处理等。经过一段时间的摸索和持续改进,取得了较好效果。1 NC-SST-I型分解炉简介NC-SST-I型分解炉,安装于窑尾烟室之上,为涡     

FR5型超短窑的特点及运行管理

晋牌水泥集团有限公司的熟料煅烧系统是引进加拿大富乐-史密斯公司,FULLER—RECIRULA鄄TION—5STAGECYCLON型超短窑。使用旋流式SF型分解炉,窑规格为准3.962m×42.672m,两档支撑,长径比为10.8,日产熟料2000t。1系统特点预热器系统设有物料再循环系统。设计思路是:使物料多次循环通过分解炉,从而增加物料在分解炉内的停留时间,以提高入窑生料的分解率。分解炉的设计容积为485m3(包括上升烟道),是一般分解炉容积的170%,确保入窑生料的分解率达90%以上。窑的长径比缩短以后,物料在回转窑内停留时间相应缩短,从而可控制C2S晶体生…     

RSP型预分解窑系统的改造

我公司Φ２．８m／２．４m×４０mRSP－４型预分解窑生产线于１９７９年建成，属于第一代RSP型试验窑，设计能力３００t／d。自投产以来，通过小改小革，回转窑达到了设计能力，但存在能耗高、入窑分解率低及产质量不稳定等问题。为此，于２００１年３月对回转窑系统进行了改造，使窑生产能力提高到５００t／d以上。１存在的问题１）分解炉炉体容积小，物料在MC室停留时间短，煤粉在炉内不能完全燃烧，常出现分解炉和C４筒温度倒挂现象，造成预热器超温，C３经常堵塞，物料分解率只有４０％左右。２）“V”型三次风管阻力太大，一般为…     

超短窑的研发设计和运行体会

0 引言 新型预分解窑诞生初期，入窑分解率一般为85％～90％，相对于传统回转窑，产量成倍提高，窑的长度缩短了很多，长径比约为16～18。随着不同分解炉的问世和对炉内燃烧气氛、物料、燃料运行速度和规律的研究，分解炉的性能不断提升，致使入窑物料的分解率在不断提高。德国的洪堡公司首先推出了长径比在10左右的超短窑，他们的学者认为，     

RSP分解窑MC室的改造

我公司２０００ｔ／ｄＲＳＰ型带有四级预热器的分解窑，由于分解炉设计结构不合理，炉体容积小，物料在ＭＣ室内停留时间短，煤粉在炉内不能完全燃烧，造成预热器超温，三级经常堵塞，物料入窑分解率只有７９．８１％。从１９９２年以来，我公司先后两次对分解炉进行改造，使得ＳＣ室和ＭＣ室工况得到改善，窑炉工艺趋于稳定。１ＭＣ室的工况基本特点ＭＣ室是窑和炉风、煤、料的平衡汇合点，从ＳＣ室进入ＭＣ室的热气流、生料和未完全燃烧的煤粉在窑和ＭＣ室之间的缩口喷出窑尾高温烟气，以较高的速度在ＭＣ室内形成喷腾运动，物料和煤粉进…     

RSP型分解炉缩口堵塞问题分析及改进

我厂3号窑是我国第一代700t/d烧煤窑外分解窑,采用RSP型分解炉,旋风预热器按2-1-1-1布置,回转窑规格Φ3.0m×45m,设计能力为27t/h。从1982年投产以来,经过多年的努力和不断改造,产质量、运转率逐年升高,生产能力达到30t/h左右,运转率稳定在85%以上。但是3号窑在运转过程中,经常发生分解炉缩口堵塞现象,严重影响窑的运转率和台产的进一步提高。1分解炉缩口堵塞的危害3号窑从投产开始一直存在分解炉缩口堵塞的问题,但有时候不明显未造成停窑,有时候堵的次数较多也比较严重,特别是2002年1～2月分解炉缩口堵塞的比较频繁,多的时候1个班堵塞1次…     

预热器五级筒内挂筒的结构改进

我公司五级旋风预热器窑规格为φ3.2m×52m,设计能力为600t/d,2004年增加分解炉后,设计能力提高到1000t/d,7月投产使用,8月即出现预热器C5挂筒脱落事故,造成堵物料导致停窑.     

旋风预热器窑优化改进与提高(下)

·PYROCLON-R分解炉:来自冷却机的三次风绕过窑并仅与窑废气和上升管道混合。·PYROCLON-RP分解炉:来自冷却机进入分解炉的三次风绕过窑并只加入到最低一级旋风筒内的窑废气中。然后将分解炉燃料喂入纯空气中,而窑废气则绕过分解炉。由于60%,最多65%的燃料进入PYROCLON分解炉,窑生料的分解率提高到约95%,通过采用较高的旋转速度,完全可以降低物料在窑内的停留时间,在窑相同位置安装1台双齿轮传动装置就可满足这一要求。一般来说,完全可以重新使用原有大齿轮和小齿轮。如果产量仍可进一步提高,那么可以安装带三次风管的分解炉,特…     

Polymorphism of LiGa5O8 and of LiGa5O8-MgGa2O4Solid Solutions

High-temperature X-ray diffraction and differential thermal analyses showed that LiGa₅O₈ exists in two polymorphs related by the first-order transition at 1138°±3°C of the low-temperature simple-cubic form, space group (probably) O⁷, to the high-temperature spinel (fcc) form, space group O _h ⁷. The transition is rapid, and the high-temperature form in pure LiGa₅O₈ could not be quenched to room temperature under the conditions used. However, the high-temperature polymorph can be quenched under equilibrium conditions when 40 mol% or more MgGa₂O₄ is present. The subsolidus equilibrium relations in the system MgGa₂O₄-LiGa₅O₈ are discussed.     

Magnetoresistance of CuxCo1-xFe2O4 Ferrites

Magnetoresistance measurements (Δ/R) were carried out on Cu _x Co_{1- x} Fe₂O₄ samples with x =1, 0.75, 0.50, 0.25 and cobalt ferrite in the range of magnetic intensity (H) from 1.0 to 4.5 kG. Linear plots were obtained between log (Δ/R) and log H for all compositions except that of cobalt ferrite. The values of n at x =0.5 do not agree with the results of some authors. The discrepancy may be attributed to the value of magnetic field intensity at which such measurements were carried out. The similarity of features of n and μ_D with composition leads us to believe that the magnetoresistance may arise from the scattering of conduction electrons by localized electrons involving the s-d exchange interaction.     

Sintering of Si3N4-Y2O3-Al2O3

Sintering kinetics of the system Si₃N4-Y2O₃-Al₂O3 were determined from measurements of the linear shrinkage of pressed disks sintered isothermally at 1500° to 1700°C. Amorphous and crystalline Si₃N₄ were studied with additions of 4 to 17 wt% Y₂O₃ and 4 wt% A1₂O₃. Sintering occurs by a liquid-phase mechanism in which the kinetics exhibit the three stages predicted by Kingery's model. However, the rates during the second stage of the process are higher for all compositions than predicted by the model. X-ray data show the presence of several transient phases which, with sufficient heating, disappear leaving mixtures of β ' -Si₃N₄ and glass or β '-Si₃N₄, α '-Si₃N₄, and glass. The compositions and amounts of the residual glassy phases are estimated.     

Expansive properties of the mixture C4ASH12 − 2CS III. Effects of temperature and restraint

The effects of temperature and restraint upon the hydration and the expansion of $\text{C}{}_4\text{A}\text{S}\text{H}{}_{12}\text{? 2}\text{C}\text{S}$ mixture compacts in different contact solutions have been investigated. Temperatures above 20°C do apparently hinder the formation of an impervious felt-like layer of ettringite around the $\text{C}{}_4\text{A}\text{S}\text{H}{}_{12}$ particles, thus greatly reducing the retarding effect of the lime. An uniaxial restraint of 1 Kg/cm² is enough to reduce sensibly the expansions which remain however high (about 100%). The results can be satisfactorily interpreted by the reaction and expansion mechanism hypothesized in our previous papers.     

Raman Study of Glasses of Ba2TiSi2O8 and Ba2TiGe2O8

Raman spectra are reported for fresnoite (Ba₂Ti(Si,Ge)₂O₈ glasses, and comparison is made between the Raman spectra of the corresponding crystalline powders and glasses of Ba₂TiSi₂O₈ and Ba₂TiGe₂O₈. The Ba₂TiGe₂O₈ glass spectra show correspondence with the Ba₂TiGe₂O₈ crystalline Raman spectra; the v _s(Ge–O–Ge) mode occurs at 518 cm⁻¹ in the glass and at 521 cm⁻¹ in the crystalline material. Five-fold coordinated titanium is the majority species present in the Ba₂TiGe₂O₈ glass as revealed by a strong band at 824 cm⁻¹ in the I glass spectrum. The Ba₂TiSi₂O₈ glass spectra are similar to the Ba₂TiSi₂O₈ crystalline spectrum; the strongest band is found at 836 cm⁻¹ in the I glass spectrum. Through comparison with the previous Raman data of other titania silicate glasses, we conclude that the Ba₂TiSi₂O₈ glass has a structure similar to the crystalline phase.     

Preparation and properties of poly(Nε,Nε-dicarboxymethyl-l-lysine)

A new ampholytic homopolypeptide, $\text{poly}\text{(N}{}^{\mathrm{\epsilon }}\text{,N}{}^{\mathrm{\epsilon }}\text{-}\text{dicarboxy-methyl-}\text{l}\text{-lysine}\text{)}$, which has one tertiary amino and two carboxyl groups in the side chain has been derived from a hydrochloride salt of poly(L-lysine). The polymer in aqueous solution seems to be in the coil form with locally extended structure (LES) at neutral pH. In both the acidic and alkaline regions, the molar ellipticity of the polymer changes as a result of change in net charge on the side chain. The conformational changes may be from the coil with LES to other coiled forms. 5–7 M NaClO₄ and 80% aqueous methanol induce the α-helix in the polymer at neutral pH. Divalent cations, Cu²⁺ and Ca²⁺, do not induce any remarkably ordered structures such as α-helix or β-structure in the polymer in aqueous solution at any pH. Ultraviolet absorption studies show an absorption peak of the polymer-Cu²⁺ complex near 240 nm. Dependence of the peak intensity on pH at various q values ($\text{q =}\text{[}\text{Cu}{}^{\mathrm{2+}}\text{]}\text{[}\text{residue}\text{]}$) indicates the two steps of the complex formation. At q less than 0.64, the formation is described only with the first step. An average coordination number for Cu²⁺ at the first step was calculated to be about 2 by the method of Mandel and Leyte. The association constant of Cu²⁺ with the residue at the step was determined from the absorption data to be far smaller than that for the Cu²⁺-EDTA complex. The second step of the formation occurs in the case of large q but the absorption data for the second step cannot be obtained exactly due to precipitation.     

Effects of metal-support interactions on the hydrogenation of CO over PdSiO2 and PdLa2O3

A study of CO hydrogenation over $\text{Pd}\text{SiO}{}_2$ and $\text{Pd}\text{La}{}_2\text{O}{}_3$ has been carried out for the purpose of identifying the effects of Pd dispersion, Pd morphology, and support composition on the catalytic activity of supported Pd. The specific activity of each catalyst for methanol and methane synthesis was determined from microreactor studies carried out at a fixed set of reaction conditions. Palladium dispersion was measured by H₂O₂ titration, and the morphology of the Pd crystallites, as expressed by the distribution of Pd(100) and Pd(111) planes, was determined from in situ infrared spectra of adsorbed CO. The crystallite morphology of the $\text{Pd}\text{SiO}{}_2$ catalysts is the same, independent of Pd weight loading: 90% of the surface is comprised of Pd(100) planes and 10% of the surface is comprised of Pd(111) planes. By contrast, the crystallite morphology of the $\text{Pd}\text{La}{}_2\text{O}{}_3$ catalysts changes with Pd loading. Primarily Pd(100) planes are exposed at low-weight loadings while Pd(111) planes are exposed at high-weight loadings. The Pd dispersion has little effect on the methanol turnover frequency over both $\text{Pd}\text{SiO}{}_2$ and $\text{Pd}\text{La}{}_2\text{O}{}_3$, for dispersions between 10 and 20%. On the other hand, the methane turnover frequency is independent of Pd dispersion over $\text{Pd}\text{SiO}{}_2$, but increases with decreasing dispersion over $\text{Pd}\text{La}{}_2\text{O}{}_3$. It is further observed that the Pd morphology influences the specific activity of $\text{Pd}\text{La}{}_2\text{O}{}_3$ for methanol synthesis: Pd(100) is nearly threefold more active than Pd(111). For a fixed morphology, the specific methanol synthesis activity of $\text{Pd}\text{La}{}_2\text{O}{}_3$ is a factor of 7.5 greater than that of $\text{Pd}\text{SiO}{}_2$.     

In situ laser raman spectroscopy of the sulfiding of Moγ-Al2O3 catalysts

Raman spectra of sulfided $\text{Mo}\text{γ-}\text{Al}{}_2\text{O}{}_3$ catalysts were obtained using in situ techniques for two sulfiding methods. For samples sulfided by 10% $\text{H}{}_2\text{S}\text{H}{}_2$ at 400 °C, MoS₂ structures were observed. A stepwise sulfiding using 10% $\text{H}{}_2\text{S}\text{H}{}_2$, with spectra recorded at 150, 250, and 350 °C, resulted in observation of molybdenum oxysulfide, reduced molybdate, and surface “MoS₂” phases. Reexposure of these samples to air led to radical modification of the oxysulfide structures as well as transformation of some sulfide phases. A model incorporating terminal and bridging MoS bonding and anion vacancies is proposed. This model is based on the conversion of isolated and aggregated molybdate and MoO₃ species to oxysulfide and reduced molybdenum phases. Conversion of reduced molybdenum phases to sulfides is observed to be slow.     

Wet Milling of Fe/Al/Al2O3 and Fe2O3/Al/Al2O3 Powder Mixtures

Wet milling of Al₂O₃-aluminide alloy (3A) precursor powders in acetone has been investigated by milling Fe/Al/Al₂O₃ and Fe₂O₃/Al/Al₂O₃ powder mixtures. The influence of the milling process on the physical and chemical properties of the milled powders has been studied. Particle refinement and homogenization were found not to play a dominant role, whereas plastic deformation of the metal particles leads to the formation of dislocations and a highly disarranged polycrystalline structure. Although no chemical reactions among the powder components in Fe₂O₃/Al/Al₂O₃ powder mixtures were observed, the formation of a nanocrystalline, ordered intermetallic FeAl phase in Fe/Al/Al₂O₃ powder mixtures caused by mechanical alloying was detected. Chemical reactions of Fe and Al particle surfaces with the atmosphere and the milling media lead to the formation of highly porous hydroxides on the particle surfaces. Hence the specific surface area of the powders increases, while the powder density decreases during milling. The fraction of Fe oxidized during milling was determined to be 0.13. The fraction of Al oxidized during milling strongly depends on the metal content of the powder mixture. It ranges between 0.4 and 0.8.