Feature

Novelty in Mixing and Agitation

Posted on 27 January, 2010 | Tags: New Technologies

Mixing and agitation is common process across various chemical industries irrespective of the manufactured product. The article describes Ekato innovations to overcome operational challenges encountered during the process for various chemical processes.

Ekato Ruhr-und and Mischtechnik GmbH, largest company of Ekato group is recognized as world leaders in process technology for more than seventy five years designs and optimises agitators as well as reactors for liquid applications. The latest innovations of Ekato RMT are

Oxidation Reactors for High Gas Flow Rates
For economic reasons, gassing reactors for bulk chemicals are being operated with ever-higher gas flow rates with an increase of vessel size at the same time. Conventional gassing systems such as sparger rings cannot keep up with these higher gas flow rates, traditional reactors become flooded. A new device for feeding gas is not arranged underneath the impeller but in the high-energy outflow area. This enables high oxygen transfer rates, as impeller flooding does not occur even in extreme situations.

Agitators for World Scale Plants
The reactor dimensions mentioned above leads into uncharted territories with respect to design. Reactors for continuous operation with volumes from 1,000 m3 upwards, with production rates of more than 1 million tons per year and vessel and power inputs of 2,500 kW or torques above 500,000 Nm reflects the technical state-of-the-art. A design that is operationally safe is only possible if the agitator with the vessel and internals is taken into consideration simultaneously. All components are subject to a finite element and modal analysis while taking into account the dynamic loads.

Draft Tube Technology for Industrial Crystallization Processes
Consistent product quality is the main goal using crystallizers in continuous operation. In most cases large particles with a narrow particle size distribution should be achieved. Draft tube technology crystallizers (DTB) are ideally suited for such applications and are specifically designed by the company to fulfill the requirements with low attrition impellers. In this way the power input can be effectively converted into a high suspension performance and a higher product quality is achieved.
Based on experimental evaluations and CFD studies concerning the draft tube, different design parameters, eg minimizing pressure losses and increasing energy efficiency are checked and adapted. In this way it has been possible to significantly increase the efficiency of the Ekato draft tube system.

Viscous Mixing
The production of viscous products often places a multitude of different requirements on the mixing system, mixing tasks such as blending, heat transfer or suspending solids have to be covered in a wide range of different viscosities and adaptable shear rates. The modular system with the Ekato Paravisc has proven to be an all-rounder for such applications with viscosities from 1 to 1,000,000 mPas. In addition, it can be combined with baffles, wall scrapers or independently driven additional mixers (coaxial or with excentric two-shaft systems) if necessary based on this wide spectrum of possibilities also an ideal solution for multi-purpose units.

Erosion Protection
Erosive agitator wear can be encountered in many ways. Coatings that is harder than the abrasive material is one practicable way. The challenge here is the chemical resistance of the coating under the given operating conditions and a secure adhesion to the metallic surface.
A new approach to this problem is the shape of the impeller blades. A blade form that offers optimal flow efficiency can hinder backflow, which is often the cause of fast, progressive impact erosion. This optimization, however, must not jeopardize the mixing efficiency. In this way the lifetime can be markedly increased with less maintenance costs.

Biological Ore Leaching (bio leaching)
Today minerals are extracted using hydrometallurgical processes in autoclaves with high pressures and temperatures. A new process uses microorganisms that can work under extremely acidic conditions. This specifically developed impeller can maintain a concentrated ore suspension during continuous operation even under gassed conditions. In this way a gentle treatment of the microorganisms is guaranteed at the same time.
This new process using biological leaching is not possible without an efficient mixing technology. The very expensive high-pressure autoclaves can be replaced with open tanks. This lowers the investment and operating costs.

Ekato Fluid
Fluid Misch und Dispergiertechnik GmbH manufactures modular and more standardized industrial agitators for the chemical industry as well as for biodiesel and bioethanol applications. The latest innovations of Ekato Fluid are

Side Entry Agitator ES 2000
Developing a cost-efficient yet well-thought out solution is an economic challenge that Ekato Fluid has taken on with the newly developed ES 2000 series for large-volume storage vessels and applications in the area of biofuels.
The current scope of supply is aimed at coping with vessel volumes according to the requirements up to 5,000 m3. Especially with side entry agitators, the choice of a reliable agitator seal is of special importance. Ekato Fluid is able to fall back on the extensive know-how of its group and can optionally offer single-acting product-wetted and double acting mechanical seals with a seal liquid device. As an additional feature, all agitators of this series are equipped with a shut-off device as a standard, which allows seal removal during maintenance even with a full vessel.
This fully-developed technology in addition to long mechanical seal lifetime are next to the low investment costs the most distinguished features of this series.

Ekato Systems
Ekato systems GmbH have specialized in ready-for-connection units for the cosmetic and pharmaceutical industry (Ekato Unimix) and mixers and dryers for processing solids (Ekato Solidmix).  The latest innovation is
S-Jet: The production of ointments, creams and emulsions within the cosmetic and pharmaceutical industries often requires the dispersion of large amounts of solids and liquids.
Ekato Systems offers the S-JET homogenizer, which is a new development, based on the proven Sterlijet design. The new 'state-of-the-art' S-JET enables the introduction of higher levels of powders and liquids. By drawing components directly into the shear zone of the homogenizer, the very finest emulsions and dispersions can be more rapidly produced. This enhanced performance and flexibility provides new possibilities for users to optimize their processes and products.
All of the advantages of the proven Ekato homogenizer systems, like the flexible operation with internal and external recirculation, the CIP-pump function of the homogenizer for good cleaning and the smooth product handling, have been retained in the new S-JET design.

Ekato ESD
ESD GmbH Ekato Sicherheits- und Dichtungstechnik develops innovative mechanical seals for all types of process engineering equipment. The latest innovations include

Central Supply Systems for Mechanical Seals
A central storage tank can supply several mechanical seals with seal liquid on demand.  Seal supply systems for operating pressures from 200 bars are already in operation. The central supply is of particular interest if large quantities of similar pressure vessels are to be operated simultaneously as it is often the case in production units in the chemical industry or in high-pressure autoclaves in minerals processing. Inspections with refilling in place are no longer necessary. This lowers personnel costs in production plant maintenance. The frequency of the automatic refill permits an evaluation of the condition of the wear parts so that wear parts can be ordered on time and preventive maintenance procedures can be planned in advance.

Non-metallic Mechanical Seal ESD42 for Side Entry Agitator Installation
The ESD42 for side entry agitators, which has been used many times worldwide and proven its worth, has been improved in detail in order to even better meet the challenge when confronted with corrosive media. This can be achieved by replacing product-wetted metallic parts with ceramic and polymer components.
Operational safety and increased lifetime are benefits that the plant operator experiences when using side entry installations in strongly corrosive media such as absorber suspensions in flue gas desulfurization plants.

Agitator Seals with Fracture-Proof Seal Rings
The ceramic parts of seal rings used in the chemical and other related industries are often damaged under extreme operating conditions and respectively require increased seal reliability with very critical media. Damage can be caused by extreme operating conditions such as rapid temperature or pressure changes which could finally lead to a total breakdown of the mechanical seal. Fracture-proof seal rings have been developed that can withstand such extremes without any difficulties. Increased lifetime and most of all increased plant safety, minimizes risks for the plant operator.