econovation – The new twirl behind your business
The presentation of the ecowirl m from econovation at the Zellcheming Expo 2012 caused a considerable stir. Company owner Daan Waubert de Puiseau explains to ipw how the idea for this in-house development arose and where the advantages of the patented system for sophisticated mixing processes arise.
A consultancy order combined with a collection of papers by the nature and vortex researcher Victor Schauberger constituted the decisive factor for the development. In his papers, Schauberger reports about special effects of vortices, their interaction and life span. He was also interested in the implosion forces. I recognised an opportunity here to achieve high contact rates through several vortices in a cyclone so as to develop new horizons concerning mixing and separating procedures.
The starting situation
I thought it would be interesting to realise multi-stage dilution processes in one step in order to make the systems for treating chemicals cleaner and simpler and to adapt reaction speeds to the possibilities offered by modern process control technology. If this were to succeed, it would possibly solve many hygiene problems in this area. After all, in any processing plant large, two dimensional deposits of polymer agglomerations like to develop at dispensing places in those unavoidable quiet areas; due to the reaction with fresh water.
Pipeline systems to the dosing point are generally kept reasonably clean by high flow rates, however the constant necessity in paper mills to save fresh water means that flow speeds are no longer sufficient, supporting the formation of ever larger polymer agglomerations.
The associated reduction in biocides is particularly critical; this may lead to the occurrence of hefty disruptions to production. The mixing dosing feeders likewise themselves form slightly disruptive agglomerations on the main pipe or in the dosing system which result in efficiency losses for the entire system. These systems are generally not a priority issue to the paper makers and usually not easily accessible! Consequently they seldom will be inspected and serviced.
We see that current mixing and dosing systems lag far behind state of technology in their direct environment. Particularly are not keeping up with today’s technology of cleaners, electro polished pipelines and the sophistications of flow stream in modern head-box designs.
The innovation introduced here, for dosing and mixing technology from Econovation is based on the generation of several interacting vortex systems, which are used for an intensive premixing procedure and whose swirl power ultimately is to achieve extraordinary mixing of chemicals within the main fibre stream.
The technical idea
The technical idea behind this innovation consists in generating an extremely stable main vortex in that way that there is no need for vortex guiding surfaces as these will always be critical in terms of depositions. This happens in a stream preparation zone, where the stream is aligned with pulsations in a radial vortex so that it flows with increasing speed to the main chamber in a side stream, and thereby drives the main vortex. The multiple inflow streams stabilize the main vortex in the cyclone chamber, so that the usual guiding blades; as are found with usual cyclone systems can be completely dispensed with.
All outflows already execute a helix vortex flow when entering the cyclone chamber, a rotational movement vertical to the direction of flow, which has a stabilising effect and facilitates a high contact rate. Added to this is the fact that the regeneration of a cyclone further accelerates all vortices and therefore permits a loosening high frequency pressure pulsation. A flow pattern with high flow at the edges is created on entry in the main pipe, so that fluid on the periphery is wrenched to the centre, keeping the outer wall of the main pipe clean of debris.
The generation of all vortices takes place before adding the additive; loss of up to 70 % of the available pressure difference is accepted. Cavitations form shatter water clusters here as well as solid agglomerations in the case of process water to increases the specific surfaces of the suspension which improve the chemical reactivity. All contiguous areas have very high flow velocities in fluid preparation, in the additive dosing zone through to the outlet in the main stream. Depositions interfering processes can be ruled out in the ecowirl.
If one considers the requirements for a rapid steady chemical reaction, one knows that the contact rate and the degree of fragmentation are decisive. The degree of fragmentation is increased during the vortex generation by cavitation effects on the ingoing stream and by separating and stretching loosening pulsations for the polymer chains in the preliminary mixing chamber.
The vortices rubbing one another will stretch tangled polymer chains so that the charged surface is exposed and already preloaded with process water ingredients. This reduces the tendency for renewed tangling in the main stream, enabling to create a surface with high load capacity. This possibly explains the considerable improvements in polymer performance as well as an improved paper web clarity we observed in individual cases.
The polymer is added when all vortices have been applied. With several thousand slowly increasing pressure pulsations and high contact rates in the pre-mixing chamber, the additive is blended into the dilution stream. The ecowirl m mixing procedure takes 500 msec only (sterile additive with a solid content of < 50 %).
Long chain, charged polymers are certainly the greatest challenge for an ecowirl m mixing dosing feeder. If a system will control reliable the mixing just before the head-box, then a number of additional applications in our industry are conceivable. Perhaps new possibilities will arise for the additive manufacturers if less consideration needs to be paid to the problems of blending.
Charged polymer chains benefit in particular from stretching effects that are increasing the specific surface of the polymers. Additives i. e. biocides, act on a high specific surface and do not need to break down poorly distributed organically sound structures. The fact that a good mixing procedure enables more even colouring also applies to dyes and pigments.
This system has been created to improve process transparency, simplicity and above all hygiene in the area of chemicals. It was firstly therefore important to discuss whether the system is able to maintain hygiene and mixing in at the same level as before with considerably less hardware. This has been proven on the installations made!
The ecowirl m operates in powder treatment applications up to a one percent solid content and with polymer dispersions up to 50 % with drive fluid in the form of clear water, classified white water and thin stock. The ecowirl m passed its initial launch in water with long chain polymers in the floatation plant of paper mills, either as direct dosing or with a powder treatment system up to 0.6 % t/s. The drive fluid is clarified clear water from the system. In floatation plants with the ecowirl af vortex blower, the function of mixing in can be performed by the blower.
Meanwhile a number of ecowirl m systems have been sold or are in evaluation. We are pleased to report from some hands on experience: Tönnesmann & Vogel, Menden, Germany, employ the ecowirl m to add prediluted and undiluted polymers into the deinking cells and to add retention agents after the vertical cleaners. They kindly permitted to perform all fundamental developments to be conducted with the ecowirl m at there plant. 25 % of the retention agent was reduced and the water line on the wire to returned to the position it should have been. Later an increase in machine speed was achieved by increasing the retention aid to the original level. Consequently ecowirl m was purchased by the customer for adding of the retention agent.
Schulte und Söhne Trebsen, Trebsen/Mulde, Germany, tested the ecowirl m for the top wire layer. A 0.5 % polymer solution prepared at a powder preparation plant was dosed with thin stock as drive fluid. A 30 % reduction was initiated by the PCS to achieve the standard turbidity readings in the white water system. The customer was so enthusiastic that he immediately bought two ecowirl m, one serving the top wire and a second for the bottom wire.
Schulte und Söhne Düsseldorf observed the success at the Trebsen plant and requested a trial for adding retention aid with a 50 % solids content dispersion in front of the head-box. This system uses a sterile, undiluted product to be mixed into the thin stock. Head-box dilution water from the cross profile control is used to generate the vortex. The simple operation of the device is totally convincing!
Leipa, Schwedt/Oder, Germany, have started a project based on the observations at the Trebsen installation and is testing a dual head system with thin stock drive fluid on the paper machine and a further dual head system for dosing the flocculent in the sludge dewatering. The new challenge with sludge dewatering is a stock density of 5 %. Currently both systems are in operation pending a final assessment of improvements.
Following an extended time test with a flocculent for flotation, the company Garda Cartiere, Riva del Garda/ Lake Garda, Italy, has put a dual head system into operation for the retention of its PM 3 with online coating machine. This paper machine runs at over 1,100 m/min and produces high quality illustration printing papers. The company welcomes the excellent accessibility and the hitherto perfect hygiene of the system. What is more, it expects higher short term process stability because an ecowirl system is largely independent of pressure fluctuations in the water mains.
All up to now users have used the delivered installation equipment and expressed its high quality tools enabling an installation with a perfect finish of all surfaces! The ecowirl technology aspires all-round perfection starting with its installation until its daily operation!
— IPW 02/2013
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