裂解汽油加氢二段反应器急冷剂管道开裂原因分析及对策

对裂解汽油加氢二段反应器急冷剂管道因化学腐蚀和应力腐蚀引起的开裂进行了溯源分析。通过对1号外管宏观及低倍金相检验、样管化学成分分析、样管显微组织分析、电镜观察及能谱分析等方式进行综合分析急冷剂管道开裂原因。确定氯离子应力腐蚀开裂起主导作用,焊缝及热影响区敏化加速了开裂进程,采取相应对策有效地防止管道开裂发生,为乙烯裂解汽油加氢装置长周期安全稳定运行提供了保障。     

二氯乙烷裂解管式反应器二维模拟

建立了二氯乙烷在管式反应器中进行气相热裂解的二维模型 ,模型考虑了二氯乙烷热解生成氯乙烯的主反应和生成焦前体的副反应以及气体密度变化对裂解反应的影响 .模拟计算表明 ,二氯乙烷和氯乙烯的浓度沿径向分布平坦 ;但是管内近壁面处由于存在边界层 ,始终存在着明显的径向温差 ;近管壁处始终是裂解的高速率区 ,副反应也主要发生在管壁区 .表明确定最优的炉管管径时必须考虑提高裂解速率与降低结焦速率之间的平衡 .在距进口量纲 1管程 0 .3左右的管壁处裂解速率达到最高 ;副反应速率的最大点位于出口管壁处 .与工业数据比较后发现 ,炉管出口的转化率、选择性、出口压力和温度等数据与模型预测值一致 ,表明模型具有较高的可信度     

塑料裂解反应器简介

介绍用于废塑料裂解的反应器的结构设计和选材,并简述其特点和应用前景。     

二醋酸亚乙酯裂解制醋酸乙烯系统中部分二元汽液平衡

用自吸循环高压平衡釜,测定了乙醛-二醋酸亚乙酯、醋酸-二醋酸亚乙酯、乙醛-醋酐、醋酸乙烯-二醋酸亚乙酯、醋酸乙烯-醋酐5组二元体系的恒温汽液平衡数据．对缔合体系的汽相采用“化学理论”修正其非理想性,采用UNIQUAC方程对液相的非理想性进行修正．计算结果令人满意．     

碳二加氢直列式三段反应器的长周期运行

国内部分乙烯装置的反应器为直列式三段反应器,这种布局方式的优点是物料流向和操作简单,但缺点是反应器的切换和再生是3个反应器同时进行,在反应器切换过程中,易发生漏炔和飞温,再生时由于温度从下到上逐渐降低,很难使催化剂再生完全,因此,保证催化剂的长周期运行至关重要。通过对碳二加氢直列式三段反应器负荷的优化分配,合理设定各段的氢与炔体积比,使反应器由原来平均运行6个月,提升到运行13个月以上,满足了装置长周期运行的要求。     

裂解汽油二段加氢催化剂工业应用

对裂解汽油二段LY-8602C/LY-9702两种国产催化剂组合成的复合床首次使用情况进行概述,跟踪考核两年来的运行情况,证明复合床催化剂既能保证生产的长周期运行,又能使装置适应多变的原料,具有较高的实用价值。     

裂解汽油一段加氢绝热反应器的开发

通过对裂解汽油一段加氢8601催化剂及 PGC 催化剂在绝热积分床反应器中的反应特性研究,考察了在工业原料条件下,入口双烯值 C_o、入口温度 T_o 以及液时空速 S_v 对双烯加氢率及反应温升的影响。并利用正交实验设计的方法,回归得到一组经验数学模型。通过误差分析以及将模型的计算值与工业实际生产数据的比较,其双烯加氢率误差小于4%,反应温升误差小于10℃,证明了该模型可以运用于入口双烯值4～12,入口温度30℃～50℃,液时空速6～12h,操作压力3.92MPa 以及氢油比0.2(分子比)的条件下,预示该催化剂在工业反应器中的反应结果,同时也可提供裂解汽油一段加氢绝热反应器的设计参考。     

微波辅助定向裂解稻壳炼制糠醛及醋酸的研究

为探索低污染、低成本的糠醛和醋酸快速制取工艺,以稻壳为研究对象,采用自行设计的稻壳高效炼制微波设备,以两步法裂解稻壳进行制取糠醛和醋酸的试验研究。在第一步裂解中使用较低的微波功率有利于提高醋酸的转化率;在第二步裂解中适当提高微波功率,使稻壳充分裂解,从而生成更多的糠醛。采用高效液相色谱仪(HPLC)测定糠醛和醋酸的含量,为糠醛和醋酸的进一步精炼提供参考。研究表明,采用两步裂解法,既避免较低功率时糠醛转化率不高,又避免使用较高功率时醋酸转化率不高的两难情况,为稻壳的转化利用提供一条新的途径。     

乙酸反应器安全阀泄放量的分析计算及选型

介绍了反应器安全阀可能超压的多种事故工况;结合实际工程经验,以乙酸反应器作为实例,分析计算安全阀最大泄放量,并根据泄放量对安全阀选型。     

Captive sample reactor for kinetic studies of coal pyrolysis and hydropyrolysis on short time scales

An apparatus has been designed for kinetic studies of coal devolatilization under closely controlled heating rates, temperatures, and pressures. The reactor system employs a wire-mesh pyrolysis furnace driven by an electronically-controlled power supply to ensure uniform heating rates and precise crossover to a variable length isothermal period; a rapid quenching scheme permits resolution of kinetic processes in 0.1 s intervals, extending the sensitivity of kinetic measurements from the initial stage of pyrolysis through to completion of primary devolatilization. Time-resolved kinetic studies on a bituminous coal in vacuo (13 Pa) and under helium (0.22 MPa) illustrate the operation of the reactor.     

单塔精馏生产优级品乙酸的研究

用理论计算与实验相结合的办法 ,采用单塔精馏生产优级品乙酸 ,以降低能耗 ,减少物料损失 ,提高产品收率 ,缩短生产周期 ,避免了双塔精馏所造成的设备与能源的浪费。在国内首次成功研究了单塔精馏生产优级品乙酸的生产工艺。     

酸-酸法合成甲基异丙基酮催化剂的研究

研究了酸-酸法合成甲基异丙基酮催化剂,利用扫描电镜(SEM)、X射线衍射(XRD)和表面酸性分析等手段,进行新鲜催化剂和评价1 300 h的催化剂表征。结果表明,催化剂的活性中心不是氧化稀土晶胞;增加氧化钕和氧化镨(RE1O RE2O)可提高催化剂的低温活性,抗积碳能力弱;加入氧化铈(RE3O)抗积碳能力强;降低酸强度有利于提高催化剂的选择性,延长催化剂的寿命。     

CO2 corrosion of carbon steel in the presence of acetic acid at higher temperatures

The corrosion behaviour of X 65 carbon steel in the presence of acetic acid in N₂- and CO₂-saturated systems has been investigated using electrochemical techniques. The presence of acetic acid does not influence the anodic reaction but strongly accelerates the cathodic reaction. The cathodic reaction and consequently the corrosion rate of mild steel in the CO₂-saturated system increase with increase in acetic acid concentration and temperature. From the values of the apparent activation energies, the corrosion reaction in the absence of acetic acid was found to be under mixed interfacial reaction/diffusion control while interfacial reaction control dominates in the presence of acetic acid. The reduction of adsorbed undissociated acetic acid on the metal surface is proposed as the key species primarily responsible for accelerated corrosion rate at all temperatures.     

Relation between mass transfer and operation parameters in the electrodialysis recovery of acetic acid

The recovery of acetic acid from dilute wastewater by means of bipolar membrane electrodialysis is studied in more detail. The current efficiency of the electrodialysis recovery of acetic acid from dilute wastewater is related to the current density and other operation parameters. There exists a highest value of current efficiency at optimal current density. The highest concentration of recovered acid is also related to current efficiency. The experimental data are analyzed on a theoretical basis.     

精对苯二甲酸氧化反应器中气体停留时间分布

对苯二甲酸的工业生产多采用对二甲苯液相催化氧化方法,因此,氧化气体的混合特性就成为氧化反应器设计、放大的重要参数。文中针对工业中采用的涡轮桨和斜叶桨组合搅拌反应器型式,以氢气为示踪剂,采用阶跃激发响应技术测定了不同气量、搅拌转速下气体停留时间分布,同时开展了对二甲苯氧化试验,了解了气体混合对氧化中间产物含量影响。研究结果表明,只有当搅拌桨叶尖速度高于一个临界值,使气体接近全混的状态,才能实现单釜氧化目的产物的高收率。     

Solvent modification effect on the physical and chemical extraction of acetic acid

Combined use of inert diluents with polar modifiers enables former to be utilized for the recovery of polar value-added chemicals. The results show that polarities of both solvent and modifier are critical for efficient separations. Thus, K_D values with 1-octanol were higher than those with 1-decanol; however, those with xylene were superior to those with hexane and toluene. Increasing the amine concentrations increased the K_D values, in contrast to the trends with pH and temperature. About 33%, 79% and 67% of acetic acid was recovered using 25% (v/v) Alamine 336 in xylene, 1-octanol and 30% 1-octanol-modified xylene, respectively. Therefore, solvent modification positively affects the extraction power of inert diluents for acetic acid recovery.     

Formation and destruction of H2S in the short residence time pyrolysis of pulverized coal and model compounds

The evolution of sulphur as H₂S from three US bituminous coals, L-cystine, and thianthrene has been studied in the reflected shock region of a chemical shock tube. With heating rates of approximately 3 × 10⁶Ks^?1, to temperatures in the range 1000–2000K, ultimate yields of sulphur from 7 to 70% as H₂S are observed in as little as 1.5 ms. The most important influence on ultimate yields may be the H/S molar ratio in the fuel which corresponds in the hydrocarbons studied with the H₂S yields. Inherent mineral matter may also influence the evolution, as H₂S formation precedes light hydrocarbon formation from the two model compounds, but occurs nearly simultaneously from the coals. The overall rate of H₂S formation for the three coals is adequately described by a reaction, first order with respect to remaining sulphur, with a rate constant $\text{k=8.1 × 10}{}^7\text{exp}\text{(?}\text{15 960}\text{T}\text{) s}{}^{\mathrm{?1}}$. In the pyrolysis of all five solids, the H₂S yields are decreased to below detectable limits at temperatures >1500K. The path for destruction of the H₂S appears to be by reaction with hydrocarbons such as C₂H₂, the concentration of which becomes similar to the H₂S concentration in the temperature range 1500–1600K.