加氢反应器温度测控方案探讨

本文主要介绍几种可用于加氢反应器的温度测量元件及其结构并讨论其优缺点。结合实际项目案列，阐述加氢反应器温度测控方案，包括T型梁热电偶、多点柔性热电偶、表面热电偶在加氢反应器温度测量中的组合应用，为加氢反应器温度测量方案提供参考。     

随机温度信号互相关法测量吸热型碳氢燃料密度

为实现超临界压力下吸热型碳氢燃料密度的准确测量,以相关测量技术为基础,设计搭建了一套密度在线测量系统。该系统在间距148 mm的管道上下游安装两只具有相同热电特性的K型热电偶作为互相关法的传感器,通过对热电偶检测到的随机温度信号进行相关计算,得出该信号经过上下游热电偶的延迟时间,计算得到流体截面的平均流速,在已知质量流量后,根据质量守恒定律进而求得流体密度。采用纯物质十二烷及质量比1∶1正辛烷/正庚烷二元混合物标定测量系统精度,实验结果与文献值的最大误差在±1.2%以内,平均相对误差小于0.6%。在此基础上,对压力p = 3.0、4.0、5.0 MPa,温度T = 302.0～529.6 K,吸热型碳氢燃料密度进行测量,该方法的应用为超临界压力下吸热型碳氢燃料密度的准确测量提供了新思路。     

随机温度信号互相关法测量吸热型碳氢燃料密度

为实现超临界压力下吸热型碳氢燃料密度的准确测量,以相关测量技术为基础,设计搭建了一套密度在线测量系统。该系统在间距148 mm的管道上下游安装两只具有相同热电特性的K型热电偶作为互相关法的传感器,通过对热电偶检测到的随机温度信号进行相关计算,得出该信号经过上下游热电偶的延迟时间,计算得到流体截面的平均流速,在已知质量流量后,根据质量守恒定律进而求得流体密度。采用纯物质十二烷及质量比1∶1正辛烷/正庚烷二元混合物标定测量系统精度,实验结果与文献值的最大误差在±1.2%以内,平均相对误差小于0.6%。在此基础上,对压力p=3.0、4.0、5.0 MPa,温度T=302.0～529.6 K,吸热型碳氢燃料密度进行测量,该方法的应用为超临界压力下吸热型碳氢燃料密度的准确测量提供了新思路。     

加氢装置高压反应器床层温度测量

通过柴油加氢装置反应系统温度测量方式不同方案的对比,提出采用新型的热电偶提高加氢装置高压反应器床层温度测量的精确性,实现柴油加氢装置反应系统温度平稳控制。     

水泥厂中测温元件的使用问题及处理措施

热电偶和热电阻是水泥厂温度测量仪表中常用的测温元件。热电偶直接测量温度,并把温度信号转换成热电动势信号,通过电气仪表转换成被测介质的温度。热电阻测温是基于金属导体的电阻值随温度的增加而增加这一特性来进行温度测量。热电偶的主要应用位置在烧成系统,这里温度高,符合热电偶的应用范围,水泥厂应用最多的为K型热电偶。     

固定床加氢反应器床层温度检测

通过对固定床加氢反应器床层温度测量方式的比较,采用合理的热电偶管口形式和选择新型的热电偶检测装置,有利于加氢反应器床层温度的精确测量,从而有效的推动了加氢装置的大型化发展和长周期平稳运行。     

基于STM32单片机的电阻炉智能温度控制器的设计

设计了以STM32单片机为核心的电阻炉温度控制策略,采用K型热电偶温度传感器和MAX6675数字转换芯片组成测温电路,SSR固态继电器作为执行元件实现对电阻炉温度的智能控制。该设计方案具有高效、高精度及智能化的特点。     

基于遗传算法的K型热电偶非线性校正

针对直接用遗传算法对K型热电偶进行曲线拟合出现的不足,如收敛过早及局部搜索能力效果差等,采用基于遗传算法的逐步逼近来拟合。考虑到K型热电偶非线性程度不高,提出一种改进遗传算法的非线性校正。经过3次不同适应度函数,同时对遗传算法中的交叉和变异操作进行适当的改进,拟合数据参考标准K型热电偶分度表。最终拟合出电压温度关系函数。通过对比不同方法的拟合结果,表明新方法能实现更好地进行非线性校正,且拟合精度高,相对误差控制在1%以下。     

BAA-8602分子筛上苯/乙醇烃化反应的动力学研究与反应器工况模拟分析

用内循环、无梯度反应器在常压、550～720K 下考察了在 BAA-8602分子筛催化剂上进行苯/乙醇气相一步合成乙苯的宏观动力学规律;建立了相应的幂函数型动力学模型。利用所建立的模型对拟应用此技术年产1250t 乙苯的工业反应器的操作工况进行了模拟计算与分析,考察了反应初始温度与原料的初始苯醇摩尔配比对反应器内温度分布、苯转化率以及乙苯选择性等指标的影响规律。     

加氢精密分馏装置反应器温度检测设计优化

针对某加氢精密分馏装置反应器高温、高压以及温度波动大的工艺特点,综合考虑反应器温度检测方案的整体成本、安全性和操作维护等多种因素,提出了一套合理可行的加氢反应器温度检测设计理念,采用了多点热电偶与柔性铠装热电偶相结合的选型方案,既提高了反应器温度检测的精确性和实时性,确保床层温度控制的稳定可靠,又保证了温度仪表的使用安全和维护方便,并降低了使用成本。     

焦炉煤气部分氧化制甲醇合成气研究

应用ChemCAD软件,采用吉布斯反应器模型对转化炉进行模拟,分析了温度、压力、进气量等各工艺条件对反应的影响。模拟结果表明,焦炉煤气部分氧化制取合成气适宜的操作条件为:进气温度500℃,反应压力1.85 MPa,进入转化炉各物流的摩尔流量COG(焦炉煤气):H_2O:O_2:CO_2=1:0.8:0.21:0.095。     

甲醇脱水制二甲醚绝热固定床反应器模拟设计

提出了绝热固定床二甲醚反应器的数学模型，利用该模型对目前工业使用的绝热型二甲醚反应器的计算表明，模拟计算与实际二甲醚反应器的操作吻合。同时还计算考察了压力，进口气体温度与流量对反应器操作的影响。     

A heterogeneous chemical reactor analysis and design laboratory: The kinetics of ammonia decomposition

A laboratory module for senior-level reaction engineering/reactor design students is described. Students use low-conversion experimental data to explore and characterize the kinetics of ammonia decomposition over various supported catalysts at atmospheric pressure in a packed-bed reactor. Each student team is assigned one of four catalyst types, a reactor temperature, and a series of feed flow rates and compositions. Aggregate data from all student groups is then summarily analyzed per catalyst type. In each experimental trial, the reactor conversion is determined by a thermal conductivity measurement applied to the feed (reactor bypass) and reactor effluent gases. An analysis of the reaction rate across a range of temperatures and varying feed gas partial pressures allows students to test various reaction mechanisms, to suggest rate-determining steps, and to statistically determine rate law parameters. Students typically use the Langmuir–Hinshelwood–Hougen–Watson (LHHW) approach to derive rate law expressions, and determine rate constants through application of the Arrhenius equation. High student numbers (ca. 140) are accommodated through the availability of four experimental stations — each sharing a common source of feed gas and equipped with independent flow controllers and gas analyzers.     

Fast-mode alternating cyclic operation in trickle beds at elevated temperature for foaming systems

An alternating gas/liquid fast-mode cyclic operation procedure was explored for reducing the occurrence of foaming flow regime in trickle-bed reactors at elevated temperature and moderate pressure. The effects of temperature and split ratio on the electrical conductance and pressure drop time series were analyzed for the air-aqueous cetyltrimethylammoniumbromide (CTAB) foaming and air-water systems. For the split ratios studied, it was found that fast-mode alternating cyclic operation could enlarge the operational domain of the low interaction regime at elevated temperature. Hence, increased reactor temperature was suggested to allow faster foam drainage and breakdown which was reflected in the lower pressure drop levels as well as in the faster collapse in pressure drop when the flow was switched from gas to liquid feed. Also, by adjusting the split ratios it was possible to reduce the two-phase pressure drops in cyclic operation below the levels corresponding to the equivalent barycentric constant-throughput operation.     

连续相变的加氢反应器

引　言加氢反应是一类强放热反应 ,在采用滴流床反应器的情况下 ,经常遇到由于液体分布不均而导致的催化剂不完全润湿的现象[1] 。当液体反应物中含有挥发性组分时 ,在一定条件下 ,液相反应物可能会蒸发 ,伴随着反应速度的突然增加[2 ] ,使催化剂局部过热而失活 .另外 ,由于液体在催化剂床层中的不均匀分布而使床层出现未被润湿的干区 ,在强放热反应中 ,会经常观察到出现热点 ,床层的轴向温度出现振荡[3] .两相并流向上的固定床反应器 ,由于床层内的持液量较高 ,液体分布均匀 ,催化剂能很好地润湿 ,因此有可能避免出现热点[4 ] .这种操作形…     

Further Studies on Oscillations over Nickel Wires During the Partial Oxidation of Methane

Oscillatory reactions over nickel wires during the partial oxidation of methane were investigated in a tubular continuous flow reactor made of quartz at atmospheric pressure. A modified thermocouple was designed to measure the temperature while the interposed nickel coil worked as a catalyst. Significant effects on the oscillations were observed by varying the system temperature and the feed gas composition, and by cutting off one of the reactant gases temporarily.     

便携式全自动动态配气仪的设计

运用单片机C8051F120、热式质量流量计和红外检测传感嚣,设计了闭环控制动态配气系统,给出了硬件电路和两股原料气流量分配的自控流程.配气实测对比结果表明,该系统不受环境温度和压力的影响,而且精度高,相对误差不超过2％,系统稳定时间最多只需30s.     

基于Aspen Plus用户模型的甲醇合成模拟及分析

对板间换热式甲醇合成塔建立了一维拟均相数学模型,并用四阶Runge-Kutta法求解其轴向温度与浓度分布。利用Aspen Plus中的User 2模块将其嵌入整个甲醇合成全流程进行模拟,并用取自工厂的实际数据进行验证,结果吻合良好。分析得到了原料气入口温度、操作压力、汽包压力及进料流量对反应器出口甲醇物质的量分数的影响,以及不同时期催化剂的活性分布及粗甲醇的产量分布,提出了在催化剂中后期应采取提高操作压力的措施来保证粗甲醇的产量。     

Investigation of the liquid recycle in the reactor cascade of an industrial scale ebullated bed hydrocracking unit

One of the commercial means to convert heavy oil residue is hydrocracking in an ebullated bed. The ebullated bed reactor includes a complex gas–liquid–solid backmixed system which attracts the attention of many scientists and research groups. This work is aimed at the calculation of the internal recycle flow rate and understanding its effect on other parameters of the ebullated bed. Measured data were collected from an industrial scale residual hydrocracking unit consisting of a cascade of three ebullated bed reactors. A simplified block model of the ebullated bed reactors was created in Aspen Plus and fed with measured data. For reaction yield calculation, a lumped kinetic model was used. The model was verified by comparing experimental and calculated distillation curves as well as the calculated and measured reactor inlet temperature. Influence of the feed rate on the recycle ratio(recycle to feed flow rate) was estimated. A relation between the recycle flow rate, pump pressure difference and catalyst inventory has been identified. The recycle ratio also affects the temperature gradient along the reactor cascade. Influence of the recycle ratio on the temperature gradient decreased with the cascade member order.     

水平导管内颗粒料层中的热渗透现象研究

本文针对水平导管内填充颗粒料层中的高温气体渗流现象,采用局部非平衡假设建立了多孔介质渗流传热物理数学模型并进行了数值计算。研究了不同情况下导管内填充多孔介质中的流速、气固温度和压力分布。计算结果表明,高温气体对导管内颗粒料层的热渗透作用主要是在渗流入口端区域,增大入口渗流速度以及减少给料量,导致气固温度沿轴向下降速度减慢,热渗透深度扩大,热渗透作用区域内的物料温度水平提高。在热渗透作用区域,孔隙率对流场和压力损失有很大的影响。研究结果对于移动颗粒反应器和输送机的设计与运行具有一定的参考作用。