共查询到18条相似文献,搜索用时 46 毫秒
1.
2.
3.
介绍循环流化床锅炉运行中返料中断,蒸汽负荷急剧降低被迫停炉的情况.通过回料阀配风型式由风管改造为风帽,回料阀返料风由独立罗茨风机供给后解决锅炉返料中断故障,使锅炉的运行稳定、操作控制简化. 相似文献
4.
以上海新华控制技术(集团)有限公司TiSNet-XDC800系统为例,利用DCS系统逻辑运算功能强大、逻辑信号范围大、调试时间短、控制组态灵活等优点,介绍篦冷机料封阀进入DCS控制的实际应用及改造经验。 相似文献
5.
立管移动床气固流动相图及理想料封状态 总被引:5,自引:0,他引:5
本文通过对立管移动床气固流动规律的研究和归纳,绘制了立管移动床气固流动相图。相图展示了有可能出现的13种移动床操作状态及其相互依存和转化的条件,对其中的理想料封状态的性质、存在条件和应用价值进行了专门的讨论。 相似文献
6.
循环流化床锅炉燃烧技术是一种洁净煤燃烧技术,其应对负荷变化的灵活性未来会得到更多的关注。但目前对于负荷变化的研究集中于调峰策略优化,缺乏提升CFB本身变负荷速率的影响因素研究。在CFB锅炉负荷变化时,循环流率也随之变化,并达到新的平衡态,而返料阀的结构是循环流率的重要影响因素。因此,为了研究CFB锅炉变负荷响应速率的影响因素,基于CPFD方法对某75 t/h循环流化床锅炉立管及返料阀内在循环流率变化时的流动行为进行模拟,研究不同返料阀结构对循环流率变化的响应速度。结果表明,在立管远离回料阀侧及回料阀水平横段底部存在一定的流动死区,返料阀及立管内物料仅在较小的区域内有较大的移动速度。当循环流率增加时,较小的颗粒移动区域限制了其达到更大流量平衡的时间,减弱了系统变负荷的响应速率。在松动风、流化风分别为0. 14和0. 30 m/s,循环流率从50 kg/(m~2·s)提升到60 kg/(m~2·s)时,随着水平横段长度的增加,系统响应时间先急剧减小后缓慢上升;返料阀水平横段长度与立管直径之比为3. 5时,最短响应时间为67 s。保持流化风量不变并改变松动风大小,系统响应时间随松动风量的增加而减小,但不同返料阀结构下系统响应时间的规律相似。返料阀对循环流率变化的响应速度与返料阀内的流动死区大小密切相关。 相似文献
7.
8.
9.
10.
11.
12.
气提式外环流反应器的液相流动模型 总被引:1,自引:0,他引:1
在接近中试规模的气提式外环流冷模反应装置上,就气-液两相及气-液-固三相两种情形,运用脉冲示踪-响应技术,以电导法测定反应器不同轴向位置示踪粒子年龄分布。随后,建立合理的数学模型,给出具体的定解条件,并进行参数估值,找出Pe与uL、Qg之间的内在规律。进而获得结论:改变试验条件,Pe准数在27.0-46.0变化。 相似文献
13.
The flow of surfactant-stabilized oil-in-water emulsions through wedge meters and segmental orifice meters was investigated experimentally. A flow loop consisting of wedge meters and segmental orifice meters of different shapes and sizes was designed and developed. The discharge coefficients were determined for various differently concentrated stable oil-in-water emulsions. The dispersed phase (oilrpar; concentration of emulsions was varied from 0 to 76,14° by volume. At low to moderate values of the dispersed phase concentration, the emulsions were Newtonian in nature. At high oil concentrations of 65.16° and 76.14° by volume, the emulsions were non-Newtonian pseudoplastic in nature. The single phase calibration curves of discharge coefficient versus Reynolds number are found to be applicable to surfactant stabilized oil-in-water emulsions, both Newtonian and non-Newtonian. However, in the latter case. one needs to use the power-law Reynolds number instead of the conventional one. Based on the experimental data obtained in this study, empirical expressions for the wedge and orifice discharge coefficients are given. These expressions can be used to predict the discharge coefficients for the emulsions provided that the emulsions are similar in nature to those investigated in the present work. 相似文献
14.
15.
应用散料力学与多相流理论研究非流态化气体-颗粒两相流通过垂直与倾斜管道及孔口的动力学,建立了动力学方程,用以预测各种条件下的颗粒物料通过孔口的流率.方程的计算结果与各种条件下取得的大量实验数据相吻合,从而使颗粒物料通过孔口流率的计算由经验关联逐步上升为理论预测. 相似文献
16.
A comprehensive investigation was carried out to study hydrodynamics aspects of secondary air injection in circulating fluidized beds. This article presents modeling and results of computational fluid dynamics simulations of gas-solid flow in the riser section of a laboratory-scale (ID = 0.23 m, height = 7.6 m) circulating fluidized bed with a radial secondary air injector. The gas-solid flow model is based on the two-fluid (Eulerian-Eulerian) approach, where both gas and solids phases are treated as interpenetrating continua. A granular kinetic theory model is used to describe the solids phase stresses. The simulation results are compared with measured pressure drop and axial particle velocity profiles; reasonable agreement is obtained. Qualitatively, excellent agreement is obtained in predicting the increase in solids volume fraction below secondary air ports, the accumulation of solids around the center of the riser due to momentum of secondary air jets, and the absence of the solids down-flow near the wall above the secondary air injection ports, which are the prominent features of secondary air injection observed in the experiments. 相似文献
17.
A comprehensive investigation was carried out to study hydrodynamics aspects of secondary air injection in circulating fluidized beds. This article presents modeling and results of computational fluid dynamics simulations of gas-solid flow in the riser section of a laboratory-scale (ID = 0.23 m, height = 7.6 m) circulating fluidized bed with a radial secondary air injector. The gas-solid flow model is based on the two-fluid (Eulerian-Eulerian) approach, where both gas and solids phases are treated as interpenetrating continua. A granular kinetic theory model is used to describe the solids phase stresses. The simulation results are compared with measured pressure drop and axial particle velocity profiles; reasonable agreement is obtained. Qualitatively, excellent agreement is obtained in predicting the increase in solids volume fraction below secondary air ports, the accumulation of solids around the center of the riser due to momentum of secondary air jets, and the absence of the solids down-flow near the wall above the secondary air injection ports, which are the prominent features of secondary air injection observed in the experiments. 相似文献
18.
碟片填料旋转床气阻与气液传质实验研究 总被引:3,自引:0,他引:3
实验测量了超重力旋转床气液传质反应器在采用同心环波纹碟片填料的时的气相压降和气液传质特性,对不同转速,气流量,液流量条件下的气相阻力与气液传质性能进行了实验研究和分析,结果表明干床的气相压降是相同状态下采用金属丝网填料的气相压降的60%左右。 相似文献