Investigations of the Gas-Liquid Multiphase System Involving Macro-Instability in a Baffled Stirred Tank Reactor

Bubble Sauter Mean Diameter (SMD) in gas-liquid multiphase system is of particular interest and the quantification of gas characteristics is still a challenge today. In this contribution, multiphase Computational Fluid Dynamic (CFD) simulations are combined with Population Balance Model (PBM) to investigate the bubble SMD in baffled stirred tank reactor (STR). Hereby, special attention is given to the phenomenon known as the fluid macro-instability (MI), which is a large-scale low-frequency fluid velocity variation in baffled STRs, since the fluid MIs have a dominating influence on the bubble breakage and coalescence processes. The simulations, regarding the fluid velocity, are validated with Laser Doppler Anemometry (LDA) experiments, in which the instant radial velocity is analyzed through Fast Fourier Transform (FFT) spectrum. The frequency peaks of the fluid MIs are found both in the simulation and in the experiment with a high degree of accuracy. After the validation, quantitative predictions of overall bubble SMD with and without MIs are carried out. Due to the accurate prediction of the fluid field, the influence of the fluid MI to bubble SMD is presented. This result provides more adequate information for engineers working in the field of estimating bubble SMDs in baffled STRs

Development of a Mobile Pilot Plant for the Evaluation of Novel Scrubbing Liquids for the Absorption of CO2 From Industrial Gases

Most available scrubbing liquids suffer from either high heating duties for the regeneration or vulnerability towards gas components. In order to increase the efficiency of the absorption process a novel scrubbing liquid has been developed by thyssenkrupp Industrial Solutions AG. For verifying relevance and feasibility of long-term operation of the new fluid assumptions for installation were created – conceptual design and detailed simulation of the process without detailed thermodynamic information

Multi-Scale Analysis of Integrated C1 (CH4 and CO2) Utilization Catalytic Processes: Impacts of Catalysts Characteristics up to Industrial-Scale Process Flowsheeting, Part II: Techno-Economic Analysis of Integrated C1 Utilization Process Scenarios

In the second part of this paper (Part II), the potentials and characteristics of an industrial-scale Oxidative Coupling of Methane (OCM) process integrated with CO2-hydrogenation, ethane dehydrogenation, and methane reforming processes are highlighted. This novel process concept comprises a direct conversion of methane to ethane and ethylene and further conversion of the resulted carbon dioxide and remaining unreacted methane, respectively, to methanol and syngas. In this context, the selected experimental results of the catalytic CO2-hydrogenation to methanol reported in the first part of this paper (Part I), were utilized to represent its industrial-scale performance. The experimental results of the mini plant-scale operation of an OCM reactor and CO2 removal units along with the experimental and industrial data available for representing the operation and performance of all process-units in the integrated process structures were utilized to perform a comparative techno-economic environmental analysis using Aspen-Plus simulation and an Aspen Economic Process Analyzer. The experimental procedure and the results of testing the sequence of OCM and CO2-hydrogenation reactors are particularly discussed in this context. It was observed that in the sequential operation of these reactors, ethylene will be also hydrogenated to ethane over the investigated catalysts. Therefore, the parallel-operation of these reactors was found to be a promising alternative in such an integrated process. The main assumptions and the conceptual conclusions made in this analysis are reviewed and discussed in this paper in the light of the practical limitations encountered in the experimentations. In the context of a multi-scale analysis, the contributions of the design and operating parameters in the scale of catalyst and reactor as well as in the process-scale represented by analyzing the type and operating conditions of the downstream-units and the process-flowsheets on the economic and environmental performance of the integrated process structures were studied. Moreover, the economic impacts of extra ethylene and methanol produced respectively via the integrated ethane dehydrogenation and CO2-hydrogenation sections were analyzed in detail. The required capital investment was found to be even smaller than the yearly operating cost of the plant. The environmental impacts and sustainability of the integrated OCM process were found to be enhanced by securing a minimum direct CO2-emission and energy-efficient conversion of CO2 and the unreacted CH4, respectively, to methanol and syngas. Besides producing such value-added by-products, efficient operation of downstream process-units was secured by minimizing the energy usage and ethylene losses. Under the considered conditions in this analysis, the specifications of the finally selected integrated OCM process structure, providing the fastest return of investments (less than 8 years), are highlighted.DFG, 53182490, EXC 314: Unifying Concepts in Catalysi

Sequential Flowsheet Optimization: Maximizing the Exergy Efficiency of a High-Pressure Water Scrubbing Process for Biogas Upgrade

Biogas is an important renewable energy source and potential raw material for the chemical industry. Its utilization frequently requires a treatment and/or upgrade step. The aim here is to maximize the exergy efficiency of a high-pressure water scrubbing process for upgrading biogas into biomethane by coupling a sequential modular simulation flowsheet with different optimization algorithms. By setting adequate operating pressures, and reducing cycle water and stripping air flowrates, an exergy efficiency of 92.4% is reached.DFG, 53182490, EXC 314: Unifying Concepts in Catalysi

The Systematic Design of CO2 Capture Rocesses Applied to the Oxidative Coupling of Methane

The oxidative coupling of methane is the catalytic conversion of methane into ethene. Carbon dioxide is generated as a reaction by-product and must be removed from the gaseous stream. In this paper, the application of a hybrid carbon dioxide removal process including absorption with amines and gas separation membranes is investigated through simulations and cost estimations

The Systematic Design of CO2 Capture Rocesses Applied to the Oxidative Coupling of Methane

The oxidative coupling of methane is the catalytic conversion of methane into ethene. Carbon dioxide is generated as a reaction by-product and must be removed from the gaseous stream. In this paper, the application of a hybrid carbon dioxide removal process including absorption with amines and gas separation membranes is investigated through simulations and cost estimations

Mobile Pilot-Plant for the Evaluation of Novel Scrubbing Liquids for the Absorption of CO2 from Industrial Gases

Most available scrubbing liquids suffer from either high heating duties for the regeneration or vulnerability towards gas components. In order to increase the efficiency of the absorption process a novel scrubbing liquid has been developed by thyssenkrupp Industrial Solutions AG. For verifying relevance and feasibility of long-term operation of the new fluid assumptions for installation were created – conceptual design and detailed simulation of the process without detailed thermodynamic information

Hydroformylation of 1-Dodecene in Microemulsions: Operation and Validation of Lab Results in a Miniplant

A method of hydroformylation to convert long- chained olefins, using tunable microemulsion systems, tests were conducted on a mini-plant at the center InPROMPT/TRR 63. Surfactant allowing a quasi-homogeneous reaction of olefin in aqueous Rhodium catalyst solution