HAZOP study of a fixed bed reactor for MTBE synthesis using a dynamic approach

A methodology for hazard investigation based on the integration of a mathematical model approach into hazard and operability analysis is presented. This approach is based on mathematical modelling of a process unit where both steady-state analysis, including analysis of the steady states multiplicity and stability, and dynamic simulation are used. The dynamic simulation serves for the investigation of consequences of failures of the main controlled parameters, i.e. inlet temperature, feed temperature and feed composition. This simulation is also very useful for the determination of the influence of failure duration on the reactor behaviour. On the other hand, the steady state simulation can predict the reactor behaviour in a wide range of failure magnitude and determine the parametric zones, where shifting from one steady state to another one may occur. A fixed bed reactor for methyl tertiary-butyl ether synthesis was chosen to identify potential hazard and operational problems of a real process. Presented at the 34th International Conference of the Slovak Society of Chemical Engineering, Tatranské Matliare, 21–25 May 2007.     

STUDIES ON FISCHER TROPSCH SYNTHESIS OVER Fe-Cu-K CATALYST Ⅱ.PRODUCT DISTRIBUTION AND COMPOSITION

In part I, we investigated some behavior of copper- potassium promoted iron catalyst for the synthesis of hydrocarbon from hydrogen and carbon monoxide, with particular attention to the influence of reaction temperature, operating pressure, space velocity, H2/CO ratio in feed gas and particle size of catalyst on CO conversion. In this part, more attention was paid to the whole product distribution, such as wax, oil, oxygenate and the composition of oil and oxygenate. It is seen that the operating conditions greatly affect the whole product distribution and its composition.     

固定床反应器——科学、技术和艺术

本文是关于固定床反应器现状及可能发展的综述。作为一种传统的反应器，固定床反应器在模型理论上已相当完善。但是由于模型和模型参数的不确定性，要通过模型化来实现优化操作几乎是不可能的。因而从科学方法的观点提出了基于状态估计和参数估计的动态优化方法。固定床反应器的一种可能发展趋势是与有关的一种(或几种)技术结合，最有可能的是与膜技术结合或与催化剂设计技术结合，实现反应一分离的综合日标。最后，本文叙述了组合已有的化学工程的原理和技术，使固定床反应器在降低能耗、提高收率等方面取得的进展。     

KINETICS OF SULFUR POISONING IN A FIXED BED FOR F-T SYNTHESIS OVER COMMERCIAL Fe-Cu-KCATALYST

IntroductionSulfurpoisoningofanironcatal}'stisoneofthemostseriousdcactivationproblemsincomn'crcialproductionofsubstitutingnaturalgasforcoalreportedb}'Bartholomc\\ofal.II1andAndersonofal.12I.Thecommercialco-precipitatedFo-Cu-Kcatal\'stpreparedb}'Instituteo…     

含氮合成气在三相淤浆床-固定床中直接合成二甲醚

在三相淤浆床－固定床反应装置中,研究含氮合成气直接合成二甲醚。使用双功能混合催化剂,粒度为0.15 mm～0.18 mm。在220 ℃～260 ℃、3.0 MPa～7.0 MPa、空速1 000 mL·g-1·h-1时考察了温度、压力及两种反应器中催化剂的装填比例对CO转化率及二甲醚选择性的影响。结果表明,一氧化碳转化率随反应压力的增加而提高,随着温度升高二甲醚的选择性变化不大,CO转化率的升高较明显,因此在催化剂活性适宜的温度范围内,该反应装置可以采用较高的反应温度。当260 ℃、7.0 MPa、三相床与固定床中催化剂比例为1∶1时,CO的转化率可达84.5％,二甲醚的选择性为78.7％。淤浆床－固定床反应装置具有操作稳定性好、CO转化率高的优点。催化剂在该装置中反应370 h活性没有明显下降。     

Ru和Cu助剂对费托合成Fe基催化剂反应性能的影响

研究了Ru和Cu助剂对无K的费托(F-T)合成Fe基催化剂的织构性质、物相结构、还原和碳化行为的影响.在n(H2)/n(CO)=2.0,t=260℃,P=1.5MPa和GHSV=2000h-1的条件下,采用固定床反应器考察了Ru,Cu助剂对Fe基催化剂费托合成反应性能的影响.采用低温N2物理吸附、X射线衍射、穆斯堡尔谱...     

Inorganic Ion Exchangers for Cesium Removal from Radioactive Wastewater

Ion exchange is a proven process for radioactive wastewater decontamination, where inorganic sorbents are ideal due to their thermal, chemical and radiation stability. This review focuses on the removal of Cs⁺ by inorganic exchangers, viz. zeolites, titanosilicates, hexacyanoferrates metal oxides and hydrous metal oxides, bentonite/clays and the key family of ammonium phosphomolybdates (AMPs). The design of new selective composites is also addressed focusing on those based on AMPs, hexacyanoferrates and titanosilicates/zeolites. Future inorganic Cs⁺ exchangers will encompass promising solids, like lanthanide silicates, sodium titanates and metal sulfides. The sensing ability derived from the photoluminescence properties of lanthanide silicates and the efficiency of layered gallium-antimony-sulfide materials in acidic and basic solutions disclose considerable potential for real applications. The ion exchange systems are discussed in terms of sorbent capacity and selectivity (with competitors), pH, temperature and solution salinity. The microscopic features of the exchangers and the associated mechanisms (e.g., pore size, counterions radii, dehydration energy of the ions, coordination environments in the solid exchanger, and site accessibility) are always used for interpreting the ion exchange behavior. On the whole, more than 250 publications were reviewed and a large compilation of data is provided in Supplemental Material.     

固定床反应器中Ti-MWW催化H2O2分解

在固定床反应器中,H2O2与Ti-MWW分子筛的接触时间越长,其分解率越高.结果表明,分子筛骨架Ti和其拥有的酸性位是造成H2O2在分子筛上分解的主要原因,非骨架Ti对H2O2分解的影响弱于骨架Ti.H2O2的无效分解直接影响反应物的转化效率.了解H2O2无效分解的原因,有利于设计出高活性钛硅分子筛.同时在固定床中研究钛硅分子筛催化分解H2O2的反应有可能成为一种评价钛硅分子筛催化活性的新方法.     

不同金属化合物催化呼和浩特煤加氢气化实验研究

在加压固定床反应器上考察了K₂CO₃、Na₂CO₃、Ca(OH)₂、Ni(NO₃)₂催化剂对呼和浩特煤加氢气化反应的催化效果,并考察了温度对催化剂效果的影响。实验结果表明,不同种类的金属化合物对气化反应的催化效果有明显影响,催化活性依次为K> Na> Ni> Ca。与原煤气化相比,在相同时间内达到相同碳转化率时,碱金属化合物K₂CO₃的加入使原煤加氢气化的气化温度降低150℃以上,碱金属化合物Na₂CO₃降低约150℃,过渡金属化合物Ni(NO₃)₂降低50℃以上,碱土金属化合物Ca(OH)₂的加入会吸收一部分CO₂产品,表观上反而降低了碳转化率。SEM及BET表征结果表明,煤样负载不同金属化合物催化剂后表面形态及孔结构有一定差异。     

Continuous enantioselective hydrogenation of activated ketones on a pt-cd chiral catalyst: use of h-cube reactor system

Summary The Pt-alumina-CD catalyzed enantioselective hydrogenations of ethylpyruvate (EP), ketopantolactone (KPL) and methyl benzoylformate (MBF) have been studied at first in an H-Cube flow hydrogenator in toluene and toluene + acetic acid. Based on the experience of previous studies carried out in batch-reactor and continuous flow systems, some parameters were kept constant (amount of catalyst, 380 mg; substrate concentration, 0.18 mol/L; temperature, 283 K), whereas others, namely chiral modifier (CD) concentration, hydrogen pressure and total liquid flow (TLF: substrate + modifier + solvent) were varied. In the course of enantioselective hydrogenation (R)-products were formed in excess: in the case of EP, KPL, MBF: 90, 60, 80 % enantioselectivities were obtained.