用过热水蒸气干燥悬浮法聚氯乙烯

过热水蒸气较作为对流干燥剂应用的其他热载体具有一系列不可比拟的优点,其中能够有效地利用二次蒸汽和保证主要的干燥蒸汽位于再循环回路里,这就可以保证反应过程具有高的能量有效利用率。由于空气热容具有较大的比热容较高的干燥效率,因而,可以强化循环回路里的蒸汽相量,减少了必须的气相蒸发量(在沸腾条件下蒸发水分),所以,在干燥介质里没有氧,这样就能够极大的提高干燥温度。采用过热蒸汽的干燥方法仅限于干燥热稳定性的物料。在大气压下,用过热水蒸气干燥的过程,不可避免地要把物料加热到100℃。然而,在减少氧     

加压下二元液体混合物的过热极限

测定了正戊烷等正烷烃及环烷烃二元液体混合物在不同压力(0.1-2. 1MPa)和不同组成下的过热极限,从热力学及动力学角度进行了理论分析及预测,并提出简化计算方法. 对传热、闪蒸等气液传质过程的改进及安全生产,具有重要意义。     

碳氢化合物及其混合物的过热极限研究

本文依据热力学原理,对碳氢化合物及其混合物的热极限进行了试验研究,并依据试验结果及文献值,对Peng-Robinson方程用于处理碳氢化合物的过热极限进行了检验。结果表明,所用实验装置测得的数据误差<3％。 Peng-Robinson方程可用于处理碳氢化合物的过热极限。     

液体混合物理论极限过热温度

应用涨落理论讨论了物质亚稳态液汽相变的机理。在考虑液体混合物核化特点基础上 ,从统计热力学涨落理论出发 ,得到了确定液体混合物极限过热温度的一般关系式。借助 P- R状态方程并外推至亚稳态区域 ,用导出的公式对不同条件下的液体混合物系统极限过热温度进行计算 ,并与文献上的 2 60组实验数据进行了比较 ,结果吻合良好     

正烷烃-表面活性剂-水的乳状液过热极限的研究

采用液滴注射法测量5种正烷烃(C6-C10)-表面活性剂-水制成乳状液的过热极限温度。结果表明，乳状液的过热极限温度随着表面活性剂含量增大而降低，含量大于某一数值后，过热极限温度趋于稳定。说明吸附在界面上的表面活性剂有利于沸腾核的形成。另外，随着乳化时的起始水油比例增大过热极限温度随之升高。     

悬浮法再生废旧聚苯乙烯的试验研究

介绍了利用悬浮法再生废旧聚苯乙烯（ＰＳ）的试验方法、工艺过程和产品质量,着重讨论了本试验对连续相（水）和分散相（ＰＳ溶液）的要求和用量,分散剂的组成和用量,搅拌速度和搅拌器形状对试验过程的影响,温度和真空度的控制,以及溶剂的回收等。本试验无“三废”排放。     

Metastable ferroelectric phase in lanthanum-doped lead zirconate titanate stannate antiferroelectric ceramics

Metastable ferroelectric phase induced by electric field in lanthanum-doped lead zirconate titanate stannate antiferroelectric ceramics near morphotropic phase boundary were studied as a function of electric field, temperature and hydrostatic pressure. Upon application of an electric field to the antiferroelectric ceramics, the rhombohedral FE phase can be induced from tetragonal AFE phase when the induced field was larger than the critical field E_AEF-FE, and the induced FE phase can remain metastable state when the electric field was removed. The metastable FE phase was unstable, which recovered to AFE phase again with the increasing of temperature at about 80 °C and the increase of hydrostatic pressure at 150 MPa, respectively. Large charge release from remanent polarization of metastable FE phase was accompanied with phase transition. The relationships of critical parameters of field-induced phase transition were also shown.     

蒸汽过热炉炉管稳定性安全分析

为分析一蒸汽过热炉炉管弯曲变形原因,对辐射过热段炉管进行传热、柔度计算和稳定性分析,得出炉管失稳原因是烘炉时管壁温度过高,自由膨胀受到约束;还就该失效炉管能否继续使用进行了简单的安全性分析。     

Drying Characteristics In Superheated Steam Drying at Reduced Pressure

The superheated steam drying at reduced pressure is performed, and the effects of operational conditions such as drying pressure and temperature on the drying characteristics are examined. In order to obtain the basic guideline for the design of the superheated steam dryer at reduced pressure, the heat flux to sample was calculated and the optimal conditions were estimated.

After the sample temperature reached at the boiling point, the temperature was maintained at the boiling point and the drying rate became almost constant. Once the sample was dried out, the temperature suddenly increased up to the drying gas temperature. From the calculation of combined heat flux, the followings were found. The contribution of radiative heat transfer to the combined heat flux became larger as the drying pressure was lower. The combined heat flux had a maximum value against the drying pressure. The optimum drying pressure, which gave the maximum heat flux, became lower as the drying gas temperature decreased. It was found that reduction in the drying pressure is effective for the enhancement in drying performance.     

Drying Characteristics In Superheated Steam Drying at Reduced Pressure

Abstract

The superheated steam drying at reduced pressure is performed, and the effects of operational conditions such as drying pressure and temperature on the drying characteristics are examined. In order to obtain the basic guideline for the design of the superheated steam dryer at reduced pressure, the heat flux to sample was calculated and the optimal conditions were estimated.

After the sample temperature reached at the boiling point, the temperature was maintained at the boiling point and the drying rate became almost constant. Once the sample was dried out, the temperature suddenly increased up to the drying gas temperature. From the calculation of combined heat flux, the followings were found. The contribution of radiative heat transfer to the combined heat flux became larger as the drying pressure was lower. The combined heat flux had a maximum value against the drying pressure. The optimum drying pressure, which gave the maximum heat flux, became lower as the drying gas temperature decreased. It was found that reduction in the drying pressure is effective for the enhancement in drying performance.     

黑索今在丙酮-水混合溶剂中介稳区的测定及关联

采用溶析结晶法测定了黑索今在纯丙酮以及丙酮与水混合溶剂中的溶解度与超溶解度,得到了黑索今结晶介稳区。用Apelblat经验方程模拟了黑索今在纯丙酮中溶解特性,用（CNIBS）/Redlich-Kister方程模拟了黑索今在丙酮和水体系中溶解特性,模拟精度均在99%以上。     

异种陶瓷的坯体无压连接

先进陶瓷的坯体连接技术提供了一种获得以现有的技术难以成型的陶瓷构件的制造方法,其工艺简单,只需将陶瓷料浆敷于需要连接的陶瓷坯体表面,把他们像”三明治”那样连接在一起共同烧结。异种属性陶瓷的连接,还可以使不同部位陶瓷适用各种具体环境条件的要求,对制造大异型和陶瓷构件的多功能化都具有重要意义。     

Comparison of Drying Rate Curves of Porous Solids in Superheated Steam to Those in Air

ABSTRACT

Drying of porous solids was experimentally investigated in superheated steam as well as in air. Drying rate curves, including critical moisture contents, in steam at subatmospheric pressure, were compared to those for air at atmospheric pressure; moreover, they were compared to those for steam at atmospheric pressure as well. The former comparison was carried out under conditions of sample temperatures of 41.8–42.5°C (which were nearly equal to saturation temperatures of 42.1–42.2°C at pressures of 8.23–8.30 kPa) for the constant rate period in steam and the corresponding sample temperatures of 42.0–45.0°C (which were close to the wet-bulb temperatures) for the constant rate period in air. There were distinct differences between normalized drying rate curves, including critical moisture contents in steam and in air at the above similar sample temperatures for materials of baked clay, firebrick, and cemented glass balloons over the minimum value of 8.3 × 10^?3 µm and up to the maximum value of 1.2 × 10² µm in cumulative pore-size distributions: longer constant rate periods and lower critical moisture contents in steam than in air, and higher drying rates in steam than in air for the falling rate period. Moreover, the latter comparison of the drying rates in steam at subatmospheric pressure to those in steam at atmospheric pressure revealed that the differences in normalized drying rates between subatmospheric pressure and atmospheric pressure were small for both materials under mild external conditions. These findings were common to the baked clay, firebrick, and cemented glass balloons over a wide range of pore-size distributions studied in the present work, as well as sintered coarse glass beads as previously reported.     

Comparison of Drying Rate Curves of Porous Solids in Superheated Steam to Those in Air

Drying of porous solids was experimentally investigated in superheated steam as well as in air. Drying rate curves, including critical moisture contents, in steam at subatmospheric pressure, were compared to those for air at atmospheric pressure; moreover, they were compared to those for steam at atmospheric pressure as well. The former comparison was carried out under conditions of sample temperatures of 41.8-42.5°C (which were nearly equal to saturation temperatures of 42.1-42.2°C at pressures of 8.23-8.30 kPa) for the constant rate period in steam and the corresponding sample temperatures of 42.0-45.0°C (which were close to the wet-bulb temperatures) for the constant rate period in air. There were distinct differences between normalized drying rate curves, including critical moisture contents in steam and in air at the above similar sample temperatures for materials of baked clay, firebrick, and cemented glass balloons over the minimum value of 8.3 × 10^-3 µm and up to the maximum value of 1.2 × 10² µm in cumulative pore-size distributions: longer constant rate periods and lower critical moisture contents in steam than in air, and higher drying rates in steam than in air for the falling rate period. Moreover, the latter comparison of the drying rates in steam at subatmospheric pressure to those in steam at atmospheric pressure revealed that the differences in normalized drying rates between subatmospheric pressure and atmospheric pressure were small for both materials under mild external conditions. These findings were common to the baked clay, firebrick, and cemented glass balloons over a wide range of pore-size distributions studied in the present work, as well as sintered coarse glass beads as previously reported.     

298K下Na+,K+//NO3-,Cl--H2O体系中硝酸盐介稳程度的研究

采用等温蒸发法研究了四元体系Na+,K+//NO3-,Clˉ-H2O在298 K时NaNO3-KNO3共饱曲线的介稳程度及湿度对该共饱曲线介稳程度的影响。结果表明：在298 K时,不管在高湿度还是在低湿度下该四元体系的NaNO3-KNO3单变量曲线介稳现象均不明显。     

基于PSO-SVM的快速甩负荷工况下过热蒸汽温度预测建模

结合海防电厂300MW机组100%负荷下的快速甩负荷试验,采用粒子群优化算法(PSO)对支持向量机(SVM)的参数进行优化,并建立PSO-SVM过热蒸汽温度预测模型。在分析试验时机组燃料量、高旁阀位开度及温度等主要参数变化过程的基础上,对过热蒸汽温度预测模型进行仿真分析。结果表明:建立的PSO-SVM过热蒸汽温度模型具有较高的预测精度,能够实现快速甩负荷工况下过热蒸汽温度的预测,维持机组安全稳定运行。