Innovative equipment and plant concepts

In this research group, innovative concepts for plants and equipment in the area of heat transfer and separation processes are investigated. The research aims to extend the application range of current technologies and introduce new concepts. Hereby, especially the performance of different types of evaporators and their design as well as the processes within distillation columns are addressed.

In the area of distillation processes, the impact of liquid viscosity on separation efficiency and capacity is explored. To elucidate the correlation between experimentally found effects and the variation of physical properties and operational parameters, we also investigate the fluid dynamics within the equipment and use models to explain and quantify the processes.

Concerning evaporation processes, thermosiphon reboilers, falling film, thin film, short path and rising film evaporators are considered in respect to their performance and operational limitations. For thermosiphon reboilers the research focusses on the modification of tubes with inserts or profiling and the application of new types of equipment such as pillow plates. The potential extension of operation range to very low pressures and the improvement of heat transfer are investigated. Falling film evaporators are generally used to evaporate products, which are thermally sensitive such as fruit juices, milk, polymer solutions and ionic liquids. Using different plants and evaporators the impact of physical properties, operational and geometric parameters is determined experimentally and modelled as well. Especially, the influence of viscosity on the heat transfer and the ability of established models for prediction is explored along with the optimization of internal flows, which are required to ensure complete wetting. Also for thin film and short path evaporators the influence of substantial and operational properties on the performance, e.g. for the thermal separation of a mutli-component fluid, is investigated. The design of the plants allows a scale-up to an industrial scale.

Some of the projects we currently work on are:

Current Projects

HV Battery Recycling for Sustainable and Functional Material Circuits: Battery Electrolyte Recycling

In the context of climate change and the securing of an independent raw material base, recycling of valuable materials for closing material loops and increasing resource efficiency is gaining importance. Recycling rates are often determined by political measures, and this also applies to lithium-ion batteries (LIB). Given the expected significant increase in the production and usage of LIB due to the ongoing trend towards electromobility, it is of great importance to develop solutions for the recycling of high-voltage batteries. At the end of the life cycle of a high-voltage battery, there is a need to recycle it in an environmentally friendly and sustainable manner and recover valuable materials to meet the growing demand for batteries while conserving resources.

The "HVBatCycle" project aims to develop innovative and sustainable processes along the high-voltage battery value chain to enable the closed-loop circulation of battery materials. This includes the selective disassembly, ecologically efficient recycling of batteries, and the production of new battery materials from secondary raw materials.

In this context, the Institute for Chemical and Thermal Process Engineering is responsible for processing recovered volatile electrolyte components. The components of the solvent mixture are to be recovered in accordance with specifications and made available for the production of cells from secondary raw materials.

Surfactants can be used to increase the two-phase heat transfer by reducing the surface tension and activating new nucleation sites. However, the current state of research is mainly based on laboratory-scale pool boiling studies, which makes it difficult to transfer the findings to the application. For example, the addition of surfactants to an evaporator can lead to degradation of the fluid dynamics while increasing heat transfer. Furthermore, the addition of surfactants can promote undesirable foam formation, which severely impairs the operation of the evaporator.

Against this background, experimental investigations on the influence of surfactants on the operating behavior and foam formation are carried out on a thermosiphon reboiler on a mini-plant scale. By varying the driving temperature difference, the submergence and the surfactant concentration, the aim is to identify operating ranges within which the addition of surfactants influences the operating behavior both positively and negatively.

Vacuum Spray Evaporator for Energy-Efficient Treatment of Pharmaceutical Production Wastewater and Production of Purified Water

Funding/Program: BMWK, ZIM

Funding ID: 16KN096702

Duration: September 1, 2022 – February 28, 2025

Clean water is not only essential for drinking but also for pharmaceutical drug preparation, making it a vital resource for life.

Over two billion people reside in regions facing high water stress, more than one billion people lack access to clean water, and over three million people die annually due to contaminated water (as of 2019). Additionally, water resources are depleting due to changing rainfall patterns, rising temperatures, and overuse. Thus, water treatment is becoming increasingly crucial.

There are already established methods for water treatment, but they all share high energy requirements or require intricate maintenance, resulting in high costs. For these reasons, there is significant interest in developing a process that offers a low-energy, cost-effective, and efficient way to purify water.

Such a system is intended to be realized through the VacuSpray project by utilizing Spray-Flash Evaporation (SFV). In this process, small droplets are sprayed into a vacuum chamber and vaporized through superheating. The non-vaporized portion of the water, known as brine, is cooled to its boiling temperature according to the pressure in the evaporation chamber. It is then further cooled in a subsequent evaporation cooler to use the brine as a coolant for condensing the vapor. This helps increase the heat recovery efficiency of SFV, thereby enhancing the process's energy efficiency.

No equipment components with high energy consumption are required. Due to the low temperature conditions below 100°C, water heating can be achieved through solar thermal or waste heat. Another advantage is the extremely simple design with few moving parts.

The method developed under the VacuSpray project combines two existing water treatment processes: the SFV process and the Humidification Dehumidification (HDH) process. It utilizes the high evaporation rate of SFV through flash evaporation and the energy efficiency of HDH through effective heat recovery.

The goal of the VacuSpray project is to create a pre-production model of such a Spray-Flash Evaporation system with an evaporation cooler for the energy-efficient treatment of pharmaceutical wastewater and the production of purified water.

Contact Persons: Anna Denecke, Katharina Jasch

Funded by: Federal Ministry of Education and Research, Germany (BMBF)
Project Management: Karlsruher Institute of Technology (KIT)
Project ID: 02WQ1535B
Time: 01.07.2020 – 30.06.2023

During waste water treatment in sewage plants, sewage sludge is a residual product rich in both raw materials and energy. Considering that immissions need to be as low as possible and to comply with increasing environmental protection regulations, the use of sewage sludge in coal-fired power plants or as a fertilizer in agriculture will become less and less possible in the future. Therefore, new strategies are required to achieve the highest possible resource and energy efficiency using a combination of biological, chemical and thermal processes.

The collaborative project "CYKATT - Design and evaluation of cyberphysical wastewater treatment plant concepts with thermally highly cross-linked subprocesses" aims to develop methods and models for the design and operation of thermally highly cross-linked wastewater treatment plant concepts. Thereby, besides the evaluation of these novel thermally highly cross-linked sludge treatment processes, their application in existing wastewater treatment plants can be investigated. Since modern ICA systems not only access a multitude of measurement data and actuators, but can also be connected to the Internet, the realization of a cyberphysical system is conceivable. In such a system, the virtual wastewater treatment plant is part of an ICA system, which allows the implementation of advanced operating strategies for flexible plant control. Therefore, the project will develop concepts for cyberphysical wastewater treatment plants with thermal sludge treatment, which support the goal of a sustainable and energetically optimized wastewater treatment.

Contact: David Appelhaus

Funded by: DFG/AiF–Cluster (CV) 6
Project Management: Research Association of the German Food Industry
Project ID: DFG 40 806 2554
Time: 2018 – 2021

Undesired foam formation is a serious matter in today’s industrial production of food and beverages as well as in the field of CO2 post-combustion capture technologies due to the direct consequences of impairment in production or even production down-times.

In distillation columns, for example, foam formation results in increased pressure drops and a reduction in the operational and separating capacity. Until now, high safety loadings, complex trial-and-error processes and the usage of antifoaming agents are the only measures to control these negative impacts.

The DFG/AiF research cluster aims at the development of an interdisciplinary approach to prevent, inhibit and destroy foams in industrial processes using exclusively physical methods. Within this framework, the following subprojects are carried out at our institute.

Subproject 4“Design of processes and apparatuses for the evaporation of foaming fluid-systems”
Subproject 4 focusses on the foam formation under boiling conditions. A mini plant thermosiphon reboiler is taken into operation to evaluate different foam management strategies such as the introduction of ultrasound or the incorporation of hiTRAN elements. Furthermore, the variation of operational parameters such as heat flux and liquid levels are examined.

Contact: Laura Strodtmann M. Sc.

Subproject 7“Development of a strategy to control the formation of undesirable foam in the chemical and food processing industry”
Subproject 7 aims at the evaluation of foam formation in distillation columns, for instance, thermal desorption units. In comparison to subproject 4, the operation of a pilot plant enables the additional examination of foam characteristics in a glass column used for thermal separation. Furthermore, the findings of subproject 4 are used to compare the Scale-Up from the mini plant (subproject 4) to the pilot plant in subproject 7.

Contact: Rolf Staud M. Sc.

Funded by: DFG
Project ID: SCHO 842/12-3
Time: 01.05.2017 – 30.04.2020

Chemical reactions do not yield the desired product alone, but also a variety of byproducts and unreacted educts. Hence, separation processes are of great importance in the process industry. Particularly the distillation is of importance and the most frequently used technique for the separation of mixtures. The separation performance of distillation columns and the fluid dynamics within the apparatus are strongly influenced by the physical properties of the substances, which are processed. However, for viscous liquids no data is available in open literature and standardized test systems to investigate the influence of viscosity are not available. Due to that, suitable mixtures need to be identified and investigated in order to describe both mixture properties and correlated separation efficiency on a theoretical and experimental basis. The aim is to improve available models and conduct suitable data for a more detailed column engineering.

Contact: Sven Gutperl M. Sc.

Funding/Program: DFG
Funding ID: JA 3030/3-1
Project ID: 539483785
Duration: October 1, 2024 – September 30, 2027

Whey proteins can form undesirable deposits under thermal stress. This process is known as fouling and consists of deposit interactions and erosion during continuous operation of the technical apparatus. Fouling in micro-structured equipment reduces heat transfer and narrows the cross-section flow area of the microchannel. Finally, the product quality as well as the function of the apparatus is severely impaired. Thus, industrial equipment often is oversized in its design to mitigate the impacts of fouling.

The aim of the project is to clarify the fouling process and to decouple the individual processes of deposition and removal during the formation process. In this project, the thermally induced fouling of whey proteins in a micro-heat exchanger designed in the preliminary project is examined. Both the initialization phase by exceeding the limit temperature, which leads to the denaturation of the protein, and the duration of the temperature effect are considered. In an existing micro-heat exchanger test rig, temperature curves and fouling phenomena are determined experimentally at the ICTV using optical measurement methods. This is carried out in both single and multi-channel systems. The measurements are accompanied by KIT using CFD simulations of the spatially and temporally resolved protein layer. With the help of a holistic modeling approach and the linking of experiment and simulation, mechanistic partial models can be determined and local area-based fouling resistances can be calculated. Based on this work, it should be possible to determine both the local and integral fouling behavior across scales so that the formation of deposits in conventional apparatus can be predicted.

Contact: Caroline Otto

Research projects finished during the last 5 years

Rising film evaporators are characterized by the flow direction of the feed. In this case the feed is pumped from the bottom towards the top of an evaporation pipe. During this process a part of the feed changes its state from liquid to vapour and an annulus flow is formed. In the center of the pipe the exhaust vapour flows at high velocity towards the upper part of the pipe. On the wall the annulus thin film is driven by the power of the upwards stream against gravity. In rising film evaporators due to the high vapour velocities the danger of droplet entrainments is increased. Therefor suitable entrainment protections must be installed. At the same time high vapour rates are required to let the film rise. Advantageous single pass of the fluid, the simple design and short resident times.

At the institute a stainless steel rising film evaporator in pilot-plant scale is installed. The evaporation pipe has the dimensions of 2500 mm x 30 mm x 2 mm. The Feed and the concentrate glass vessels possess a double shell. Further the connection pipes are electric heatable. This result in the possibility of evaporate liquids near its solid state. On the heating side different fluids can be used to hit the preferable heating parameters. On the one hand a thermodynamic analysis due to the evaluation of the measurement points is possible. On the other hand a high velocity camera allow to observe the droplet entrainment at the inlet of the liquid/vapour separator.

Funded by: AIF/ZIM
Project ID: KF2614405ST4
Time: 01.03.2015 - 28.02.2017

Within this project, diverse image analysis methods are combined with a new measurement technique to investigate the properties of falling films. It focuses on the evaporation of highly viscous and particle loaded liquids. The use of the new method of film analysis in combination with a thorough investigation of heat transfer enables optimizing of the design of falling film evaporators for problematic liquids. Thus, heat transfer can be improved with optimized internal flows. Hence, equipment costs are reduced. Moreover, electrical energy is saved through a decreased pump duty.

Chemical reactions do not yield the desired product alone, but also a variety of byproducts and unreacted educts. Hence, separation processes are of great importance in the process industry. Particularly the distillation is of importance and the most frequently used technique for the separation of mixtures.
The separation performance of distillation columns and the fluid dynamics within the apparatus are strongly influenced by the physical properties of the substances, which are processed. However, for high viscous liquids no data is available in open literature and up to now no standardized test systems existed to investigate the influence of viscosity. Therefore, such a mixture was chosen and characterized. Using this mixture, experiments were carried out at a wide range of operating conditions. Then, the determined effects are quantified and modelled.
To achieve an understanding of the effects inside the apparatus and their interdependencies, not only distillation experiments in the miniplant scale are carried out, but also optical methods are used to investigate the fluid dynamics of liquid on structured surfaces.
The aim is to improve models and thereby allow a design of columns even for high viscosities and unusual operational conditions.

Thermosiphon reboilers (TSR) are widely used as reboilers in the chemical and petrochemical industry. The main reasons are the low investment and operating costs. Heat transfer and fluid dynamics are strongly linked in thermosiphon reboilers. Therefore, the operation range of these evaporators is limited. To expand the operation range a TSR with pillow plates is investigated at the ICTV. Furthermore, the research objective is the development of short-cut design equations.

Funded by: Federal Ministry for Economic Affairs and Energy (BMWi)
Project Management: PTJ Jülich
Project ID: 03ET1395I
Time: 01.11.2016 - 31.10.2019

The BMWi-Joint-Project aims at the improvement of energy and resource efficiency of fluidic separation processes due to the reduction of droplet entrainment in vapour/liquid counter current processes.
An insufficient phase separation and droplet entrainment significantly influences the efficiency of thermal and fluidic separation processes. Within TERESA all relevant intersection points of a separation column, a) the feed pipe up to column entrance, b) entrance zone within the column, c) column head and d) the column sump or the vapour separator after a flash evaporator will be considered.

Workpackage 4.3 “Experimental investigation of column sump/flash evaporator“
Part of the ICTV is to investigate the influence of different materials, instruments and varied operating conditions on droplet formation and entrainment. The results will be expressed by dimensionless numbers which will help to develop new flow maps depending on droplet diameter and/or droplet distribution beside default parameters like flow velocity and phase fraction. These advanced flow maps will be used to estimate optimal operating conditions, without droplet entrainment, for given separators.

Workpackage 1 „Communication and dissemination“
The ICTV is responsible for the technical and scientific communication in the cooperative project.

Contact: Dr.-Ing. Katharina Jasch

Funded by: Federal Ministry for Economic Affairs and Energy (BMWi)

Project sponsor: Jülich

Project ID: 03ET1471A

Time: 01.01.2017 – 31.12.2019

In this joint project the research focus is bent on the change of current batchwise production processes into continuous ones. To reach this target support is given by milli and micro production techniques as well as process integrated inline-analytics. The decreasing product life cycles result in shorter bring-to-market times. To achieve this goal it is necessary to obtain already in lab-experiments scalable results, so that the pilot-plant scale can be skipped. This is abetted by the capacity range which is situated between 100-1000 tons per year. Through a modularization of production plants, the possibility of process simulations and analytics, as well as a progressive real-time analytic and displaying, it is possible to identify scalable parameters by compliance the quality requirements.

Subtask 7.5 deals with the continuous evaporation and analysis of multi-component fluids by using a combination of thin film and short path evaporators. Both evaporator types are suitable for the preparation of temperature sensitive and viscous fluids. Even media containing solid particles can be handled until an almost dry state.

The series connection of the thin film and short path evaporators deliver access to the opportunity of selectively cut one component (e.g. a mid-boiling substance) out of a multi-component composition. In this case experiments investigate which product purities, controlled by a real-time-analytic, can be achieved by different operational settings.

Contact: Stefan Jahnke M. Sc.

Thin-film evaporators are very important for the evaporation and distillation of problematic substances and systems. On the one hand these are thermally sensitive media like they occur in the food production or pharmaceutical industry. On the other hand it is about the handling of recycling streams, which are often highly viscous, solids-containing, fouling or foaming. Especially if falling film evaporators can no longer be operated with the product, thin-film evaporators are indispensable. Due to the number of variable operating and equipment parameters thin-film evaporators can be optimized to the application and properties of the respective product. However, this flexibility has the disadvantage that the influencing parameters currently cannot be described completely. There is no generally accepted and safe calculation basis for designing or scale-up of thin-film evaporators.

Therefore this investigations at the ICTV aim for the thermal and fluid dynamic characterization of thin-film evaporators to give a calculation basis for designing and scale-up. Experiments are carried out at a steam-heated thin-film evaporator with stainless steel. By means of constructive measures it is possible to operate the apparatus as short-path evaporator or even as reactor.

Contact: Stefan Jahnke M. Sc.

Thermosiphon reboilers have been established themselves for evaporation aqueous solution and as bottom heating units for rectification columns in chemical industry. They are characterized by a high heat transfer rate, low investment and operation costs as well as simple cleaning and maintenance. Their circulation is induced by themselves due to the density difference between the single-phase inlet and the vapor-liquid-mixture at the outlet. Because of the coupling of heat transfer and fluid dynamics, the operating range of this reboiler type is limited. A description of operating behaviors of this apparatus is difficult, especially at its operating limits. The operating range of thermosiphon reboilers can be enlarged by the use of insert, so that they can be stably operated at low absolute pressures and small driving temperature differences between heat side and product side. The actual research activity is focused on the stable operating range of thermosiphon reboilers with inserts and its thermal and fluid dynamical operating behavior under low operating pressure, small driving temperature difference as well as for viscous working liquids.

Contact: Yan Lu M. Sc.

Innovative equipment and plant concepts

Current Projects

Research projects finished during the last 5 years

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