Development of technical catalysts

Heterogeneous catalysis is the backbone of the modern chemical industry. The successful development of technical catalysts requires a highly interdisciplinary approach and a permanent close interaction between catalyst and process development. Although many modern methods are available for the characterisation of catalytic materials, still no substitute for a pilot plant test is available. Therefore the application of representative testing conditions in the laboratory or pilot plant reactor is of crucial importance. In order to identify the relationships between the often complicated solid state synthesis process during catalyst manufacture, the structural properties of the catalyst and its performance, correlation analysis are used.     

Vorbeugende und konstruktive Schutzmaßnahmen gegen Gas- und Staubexplosionen

Preventive and constructional measures against gas and dust explosions. Even during the planning of plant for processing potentially explosive products, process and constructional aspects should be accompanied by investigations on the products conducted with a view to obtaining as complete a picture as possible of the danger of explosion of the materials. These studies provide the basis for estimates of explosive risks in the plant and for decisions concerning the extent to which safety measures against the occurrence of explosions or the effects of explosions can be implemented. An explosion-proof plant can be accomplished by preventive measures hindering an explosion, or by constructional measures suppressing the effects of an explosion. This paper is intended to be of assistance in the choice of explosion-proofing equipment.     

Beispiele zur Anwendung von Feinkornbaustählen im chemischen Apparatebau

Examples of the use of fine-grained structural steels in chemical plant construction . Apparatus and vessels made of high-tensile steels of types St E 36 and St E 47 have for many years been successfully employed in chemical plant construction. Special attention must still be paid to the properties of these materials in design and fabrication. This requires close collaboration between materials technologists, constructional engineers, and process engineers. Should special operating conditions have to be met with – e.g. pulsating stresses, stress corrosion, etc. – these must be taken into consideration in the materials selection and construction. The choice of material and the design greatly influence the construction requirements, and thus also the construction costs. As can be shown with examples, carefully designed and constructed apparatus and vessels have proven essential for long-term operation. Using already approved designing principles and manufacturing regulations, operationally reliable construction units for chemical plant can continue to be manufactured from St E 36 and St E 47 steels.     

Wirtschaftliche und technologische Bewertung von Verfahren

Economic and technological evaluation of processes. The process engineer is finding it increasingly important to evaluate a given process from the economic and technological standpoint, when developing a process or realizing an investment project. In order to demonstrate the possibility of a structured and systematic mode of procedure, a brief account is given of the available tools. Profitability can be evaluated on the basis of the accounting rate of return (ROI), the internal rate of return (dcf yield), and the ratio of equity, all measures that can be derived from an assessment of costs and economics. To take into account the uncertainty of the boundary conditions assumed, such as raw materials costs, selling prices, and plant utilization, it is advisable to carry out a risk and sensitivity analysis. Examples are given that demonstrate the possibility of both calculating and reducing the economic and technological risks.     

Wirtschaftlicher Einsatz von korrosionsbeständigen Werkstoffen im Apparatebau

Economic use of corrosion-resistant materials in plant construction . Particular attention must be paid to choice of materials, constructional design, and production processes in order to achieve optimum, favourably priced solutions in the planning and construction of equipment for chemical plant. In the choice of materials, special stainless steels and non-ferrous metals of recent development, should be given special attention, particularly with respect to cost-saving substitution of expensive quality materials. The use of clad steel sheet fulfills requirements for optimum design of components for many applications; however, the economic use of these composite materials must be compared with that of solid materials from case of case – due attention being given to the strength and working properties of the materials. The lining of equipment with high-quality corrosion-resistant materials is also an economic production method but its limited applicability should be borne in mind. Welding is a cost-relevant production method. Use of welding techniques with high fusion rates, which is feasible for some high quality materials, can lead to considerable cost savings. Economic production of curved plates from Superferrit Remanit 4575 is possible by welding together individual rounds.     

Chemisches Recycling von Kunststoffen

On completion of the first life cycle of plastics various recycling processes are available for further utilization of these evaluable materials. The choice of process will depend upon the materials to be recycled. In chemical recycling polymers are degraded to basic chemical substances which can be reused in the petrochemical industry. This route plays a key role for soiled waste plastics or waste plastics which could not hitherto be recycled. The pyrolysis of acrylic polymers provides a good basis for comparing a fluidized bed reactor and a tubular reactor with regard to reactor modelling. The tubular reactor with internal mass transport is a simplified model for a rotary kiln. Parameters relevant for reactor design and scale-up are presented.     

Kennzeichnende Verfahrens- und Einflußgrößen beim katalytischen Fließbett-Cracken

Characteristic process parameters and variables in catalytic fluidized bed cracking . Catalytic fluidized-bed cracking occupies a distinctive position among the various conversion processes. With regard to its favorable product range, the process is characterized by low processing costs coupled with flexibility of raw materials. A number of independent process parameters are available for control of the reactions involved in catalytic cracking and for influencing the product range. The cracking reactions taking place and the interplay of the independent and dependent variables are described. Apart from the actual cracking process, particular importance attaches to the regeneration of the catalyst charged with coke since it has a decisive influence on the thermal economy of the plant. Depending upon the desired product yield or the raw materials a suitable catalyst must be chosen. Considerable progress has recently been made in catalyst development.     

A laboratory centrifugal refining method for control application

A control method is presented for selecting the appropriate processing conditions for alkali refining of crude vegetable oils by the centrifugal process to yield lowest losses with satisfactory color. This technique is sufficiently analogous to actual processing conditions to provide reliable information upon which plant performance can be based. The cup method cannot be used in this manner in that it no longer approximates operating procedures as in the days of kettle refining. The chromatographic neutral oil method, on the other hand, provides an index of the amount of oil available for recovery without regard to the possibility of attaining such levels. For these reasons the centrifugal method fills a void of long standing. Other tangible benefits that accrue from this technique are: selection of sources of oil that can be most profitably refined by establishing the relative value of competitive oils, and a means of evaluating plant efficiency.     

低阶煤高值转化制备基础化工原料关键技术及应用

制备电石、乙炔等基础化工原料是实现低阶煤高值转化的重要技术途径,现有技术普遍存在高污染、高能耗、高成本等问题。本文介绍了国家重点研发计划项目（2016YFB0301800）拟通过揭示低阶煤在电场耦合反应体系极端条件下物质传递与转化的科学规律,深入认识反应过程调控、放大和能量回收原理,突破旋转弧等离子炬工程化技术、大电流氢等离子体电源与低电压启弧技术、长寿命电极设计及烧蚀补偿技术、低成本粉状原料成型及高温固体物料输送技术等关键技术,形成节能、高效、低成本的低阶煤生产乙炔和电石成套工艺,建成5000吨/年等离子体裂解煤制乙炔工业示范装置及80万吨/年低阶煤蓄热式电石生产工业装置。     

Lithographically patterned micro-/nanostructures via colloidal lithography

Colloidal lithography is an effective and facile strategy for highly ordered nanostructure arrays that is a simple, inexpensive, and high-throughput process with a broad choice of materials in manufacturing various lithographically patterned nanostructures on substrates. To develop such nanostructured systems, various nanofabrication techniques are employed on two-dimensional (2D) colloidal masks for evaporation, electrochemical deposition, etching, dewetting and mask replication. Ordered nanostructures associated with feature shapes and sizes can be diversified through a choice of methodology and a control of experimental conditions. This review presents an overview of colloidal crystals as a mask and nanostructure arrays (nanopillars, nanoring, nanopores) fabricated by colloidal lithography as well as introducing practical applications using ordered nanostructures.     

Verbrauchssenkung für großtechnische NH3-Anlagen durch Wärmerückgewinnung im Abhitzesystem

Energy savings in industrial NH₃ plant by heat recovery in the waste heat system. Minimization of energy consumption is nowadays a primary goal in the design of NH₃ plant. In this context two aspects are particularly important: first, the process steps and their combination must be selected in such a way that the level of energy that has to be supplied to the plant is kept low from the very beginning; second, heat recovery must be optimized by the choice of process conditions and use of appropriate equipment. An industrial NH₃ plant built according to these principles can operate at a consumption of as low as 29.5 GJ/t NH₃, using proven processes and equipment. The first plant of this new generation with a capacity of 1120 t/d is currently under construction for Canadian Industries Ltd. (CIL) in Canada.     

Extension of modifier adaptation for controlled plants using static open-loop models

Model-based optimization methods suffer from the limited accuracy of the available process models. Because of plant-model mismatch, model-based optimal inputs may be suboptimal or, worse, unfeasible for the plant. Modifier adaptation (MA) overcomes this obstacle by incorporating measurements in the optimization framework. However, the standard MA formulation requires that (1) the model satisfies adequacy conditions and (2) the model and the plant share the same degrees of freedom. In this article, three extensions of MA to problems where (2) does not hold are proposed. In particular, we consider the case of controlled plants for which the only a model of the open-loop plant is available. These extensions are shown to preserve the ability of MA to converge to the plant optimum despite disturbances and plant-model mismatch. The proposed methods are illustrated in simulation for the optimization of a CSTR.     

Liquid waste treatment in the vegetable oil processing industry—European practices

The waste treatment methods that are currently used in the vegetable oil processing industry are reviewed with special attention to three points: a very careful study of the local conditions is necessary before selecting any treatment process; in any case, it will mean an expensive investment, and the running costs will be high; and, in the near future, new laws will leave no choice to plant owners—they will have to comply with legal requirements or close up shop.     

大型硫磺制酸装置的设计及探讨

介绍了l800t／d硫磺制酸装置的设计概况，重点阐明了工艺方案的选择、主要设备的选型和材料的引进，并对设计参数的选取和低温位热能的利用作了探讨。国内已有能力做好大型装置的设计和国产化，但还应不断提高设计理念和装备水平。     

Near critical and supercritical water. Part I. Hydrolytic and hydrothermal processes

The potential of hot and supercritical water in applications to produce useful products, or to process unwanted compounds into environmentally compatible materials is reviewed. The potential of hot and supercritical water is high. Water changes its character from a solvent for ionic species at ambient conditions to a solvent for non-ionic species at supercritical conditions. Water at temperatures higher than ambient boiling temperature can be applied for extraction. At modest temperatures, ionic and polar species will be extracted. At higher temperatures, in particular approaching the critical temperature, nonpolar substances are readily dissolved and extracted. Hot pressurized water has a high reactivity. The reactions are commonly summarized as “hydrolysis reactions” which are catalyzed by acids, or may arise from simply hydrothermal transformations. Since CO₂, dissolved in water increases the availability of protons, the addition of CO₂ to liquid water catalyses hydrolysis reactions. Hydrolysis of natural plant materials provides a route to obtain fuel from non-food plant material. However, difficulties associated with operating conditions have so far limited the large scale implementations.     

Upflow vertical tube evaporation of sea water with interface enhancement; Process development by pilot plant testing

Recent developments in sea water desalination in the United States indicate a trend favoring the vertical tube evaporation (VTE) process over multistage flash evaporation (MSF), primarily because of the relatively higher overall heat transfer coefficients obtainable with VTE. The Interface Enhancement method provides an approximate doubling of the heat transfer performance obtainable under the best available process conditions relevant to large plant multieffect VTE, by the addition of a selected surface active agent to the sea water feed. A versatile upflow VTE pilot plant of 5,000 gpd capacity is described and typical test data with and without the additive for heat transfer enhancement are reported. It is apparent from these data that an approximate 25 percent capital cost saving is obtainable by substituting upflow VTE with Interface Enhancement for the downflow VTE process.     

Verfahren zur Eliminierung und Rückgewinnung von Phosphor aus Abwasser

Future challenges for the wastewater treatment will be the compliance with low discharge limits for phosphorus and the recovery of phosphorus from wastewater. Under favourable wastewater conditions and optimal process operation the conventional P‐elimination techniques can reliably and economically achieve phosphorus discharge values of approximately 0.5 mg L^–1 P_total. Lower phosphorus discharge values are reached by optimization of available or implementation of advanced P‐elimination technologies. The possibilities for the phosphorus recovery are indicated on the basis of several processes. The present P‐elimination technology influences strongly the choice of the P‐recovery technique and the P‐recovery degree. On the other hand, the P‐recovery techniques can influence the operation of the wastewater treatment plant.     

Decision support for the development,simulation and optimization of dynamic process models

Simulation is besides experimentation the major method for designing,analyzing and optimizing chemical processes.The ability of simulations to reflect real process behavior strongly depends on model quality.Validation and adaption of process models are usually based on available plant data.Using such a model in various simulation and optimization studies can support the process designer in his task.Beneath steady state models there is also a growing demand for dynamic models either to adapt faster to changing conditions or to reflect batch operation.In this contribution challenges of extending an existing decision support framework for steady state models to dynamic models will be discussed and the resulting opportunities will be demonstrated for distillation and reactor examples.     

Wet-Oxidative Desulfurization as a Flexible and Greener Way for H2S Removal from Acid Gases

In wet-oxidative gas desulfurization processes, absorbed H₂S is directly converted to sulfur by a redox catalyst dissolved in a circulating scrubbing solution. High flexibility is achieved through the availability of different catalyst classes. In this work, a process based on the Takahax process was investigated in a pilot plant under industrially relevant conditions with coke oven gas. A stable plant operation without sulfur precipitation was achieved by a suitable choice of the operating conditions. The solid-free operating window was determined and a sulfur redissolution strategy developed.