22nd AFA Int’l. Fertilizers Technology Conference & Exhibition June 30th - July 2nd, 2009 Marrakech, Morocco
Solutions For High Screening Performance In The Fertilizer Industry / Future Prospective Olivier Thouvard Sales and Marketing Director ROTEX Europe
Belgium
Mr. Olivier Thouvard Sales & Marketing Director 22nd AFA Int. Fertilizers Technology Conference& Exhibition June 30th – July 2nd, 2009 - Marrakech SOLUTIONS FOR HIGH SCREENING PERFORMANCE IN THE FERTILIZER INDUSTRY / FUTURE PROSPECTIVE
1. GENERAL ROTEX PRESENTATION Rotex Global LLC- is a leading manufacturer and supplier of screening and feeding & conveying equipment to the bulk industries. The company has been founded in 1844 and is actively concentrating on the field of processing technology since then. Our innovative line of separation equipment consists of our uniquely combined Gyratory & Reciprocating Plane- as well as Vibratory- Screening Machines, Automated Particle Size Analyzers, and Vibratory Feeders & Conveyors, Rotex Products have the capability for extensive customization to meet also unusual customer requirements. Self understood is reliable & quick parts and service supply. The European daughter company, Rotex Europe Ltd., designs and manufactures in Runcorn / Manchester / UK and supplies a complete range of screening equipment to the bulk handling industries (animal and pet food, chemicals, fertilizer, mining and quarrying, plastics, recycling, sugar, etc.) The back bone of Rotex Europe’s product range are the screening machines using the combined gyratory / reciprocating motion. These are the Rotex screeners, it’s new descendant the Apex™ screeners and the MEGATEX -XD screeners for processing of high product quantities. Further on the electro-magnetic SFH or HI feeders as well as a complete range of linear motion vibratory Direct Drive screens and conveyors & feeders. Deeply involved in the mineral & fertilizer industry, Rotex has created a dedicated machine to this industry, the MEGATEX XD Screener. The MEGATEX XD Screener provides unsurpassed screening performance when exact separations and high efficiencies are required in combination with high screen loads as we find it commonly in the fertilizer & minerals field. It maximizes product recoveries even at material temperatures exceeding 200ºC.
The MEGATEX XD Screener provides excellent screening performance due to equal internal feed distribution to all screen decks, uniform bed-depth across the entire screen surface and effective prevention of screen blinding, by the use of durable declogging balls. Rotex has been supplying lots of Rotex and Megatex XD screeners on the mineral industry (Potash) and fertilizer (DAP, NPK, Urea) as one of the world leader in this field. These units are in operation all over the world including Russia, where Rotex with its local contact has been working for many years. 2. SCREENING TECHNOLOGY BASICS What does screening mean? - Screening is the process of separation of a feed stock into different particle size fractions, by comparison of the single particles with a screen mesh. The screening process will not modify the size of the particles but it will separate the feed with as high precision and efficiency as possible. Screening is a volumetric process whereby a given material is separated into two or more fractions. (Screening is predominantly linked to the volume to be handled and less to the weight e.g. for the same separation a lighter product will require more screening area.). This is accomplished by imparting a particular motion to a screen medium (mesh/perforated plate) causing particles smaller than the mesh to pass through and particles larger than the mesh aperture to be carried over. Is it an art or a science? - There are numerous conditions where the characteristics of the product are subject to the laws of nature and therefore are consistently changing, for example: • • •
Temperature – generally screening, unless under a controlled climate, can be subject to the effects of temperature differences. Material characteristics – Is the material hygroscopic, does it have an affinity to adhere to other particles, is the surface rough or smooth, is the feed fluidized or compacted, thus how does it flow, is it abrasive, does it coat the mesh, will it build up in corners a.s.o. Particle size distribution of the feed stock is of course the main parameter when designing and sizing a screener. It will be an essential information required, especially the relation of particles being smaller vs the ones bigger than the mesh aperture.
Further product characteristics to take into consideration when choosing the screening machines are: -
Bulk Density Particle Shape Flow ability Friability Surface Moisture Static Charge
Because of the need to take all these parameters into account, screening, is almost an art, and surely a matter of knowledge, experience and testing. This is where Rotex will bring value to its customers by its long and outstanding experience in the screening field. This experience is particularly critical when we are talking of fine minerals & fertilizer screening where accuracy and efficiency is deciding on the economical success of its producers and the product properties vary in a wide range. 3. GENERAL APPLICATIONS IN SCREENING AND LAY OUT •
Scalping:
The removal of a small amount of oversize material (generally less than 10%) from feed that is predominantly fines (at least 50% half-size). The mesh aperture is big compared to product’s size. Screening is comparably easy and a high feed rate can be achieved. A typical example for scalping is check screening of fertilizer before packing in to bags or loading trucks. SCALPING Removing a small amount of oversize from a feed that is mostly thrus Very high capacities are normally attainable. Oversize 5% or Less
• Fines Removal: Removing a small amount of fines from a feed material that is mostly overs. Fines are particles smaller in size than the screen openings and also called Passage or Undersize. FINES REMOVAL
Removing a small amount of fines from a feed material that is mostly overs. Fines 10% or Less
•
Grading ( also referred to as Sizing):
Making size separations on single or multiple screen surfaces.
.
GRADING Making size separations on single or multiple screen surfaces
14 M (1 mm)
30 M (0.6 mm)
60 M (0.25 mm) Oversize Product A
Fines
Product B
In this case all, or most of, the different fractions are good product, therefore accuracy and screening efficiency is most critical. A typical application is the production screening of fertilizer where overs are led back to a milling cycle And then joining the unders for recompaction, whilst the product fractions are gained. •
Declogging:
In order to promote feed capacity and screening efficiency it is important to keep the mesh clean. Therefore we promote bouncing declogging balls used underneath the screen cloth. The gyratory motion of the screener is very efficient for this declogging action. Cleaning balls are made from different materials and in different sizes depending on the applications and the product properties. For very fine separations the gyratory action can be combined with an ultrasonic device, which provides additional declogging and helps fines passage. Anti-Blinding Ball Mesh Cleaning System
•
Testing & Lay Out:
As to the required know how and experience, the testing phase is an important step during the selection and sizing of the required screener. It will allow the selection of the correct Rotex screener in order to ensure the required parameters such as feed rate, efficiency, accuracy and others. Depending on the reproducibility of trials, testing sometimes has to be done in the original production surrounding.
4. THE IMPORTANCE OF QUALITY SCREENING IN FERTILIZER & UREA APPLICATIONS Final Customers require ever more accuracy in terms of a defined particle size analysis (PSA) of the product with increasingly detailed specifications with low limits in permissible amounts of over and undersize percentages included.
The size of the urea or fertilizer particles has a direct impact to the final customers’ applications and their processes. Therefore it is important to control the PSA of the feed together with keeping the efficiency and the precision of cut as high as possible. On top of customer satisfaction with good screening operations, accurate and efficient screening will also allow successive processes to work more efficiently. by requiring less energy: e.g. feeders, compactors, mixers and mills. 5. DIFFERENT SCREENING TECHNOLOGIES • • •
Vibrating throwing screeners with circular or rectangular shape with 1 or 2 vibrating motors. Electromagnetic vibrating screeners with low stroke and high speed. Screener with combined gyratory and linear horizontal movement, e.g. Rotex type, with large stroke from 30 to 90 mm and low speed from 200 to 400 Rpm. Operation for scalping with high feed rates and fine separation for accurate and efficient screening. The gyratory movement with the support of the bouncing ball action increases the ability of the particles to go through the mesh in order to achieve the required efficiency.
•
Centrifugal equipment and plane sifters have limited applications in mineral & fertilizer plants.
6. BENEFITS OF EFFICIENT AND ACCURATE SCREENING: The increasing energy and raw material cost require increasingly efficient screening processes. Efficiency in screening machine is the relationship of the product gained vs the product fraction supplied in the feed.
TOP : 1030µm LOWER : 540µm
Rotex Giratory screener
ES
OV ERS
FIN
PR
500µm
FINES
High feed rate On spec product
O DU CT
500µm 1000µm
PRODUCT
1000µm
OVERS
For best efficiency the lowest possible percentage of onsize product maybe recycled by being not being gained as product. Screening is no black and white separation of particles bigger or smaller than the mesh size, since a three dimensional particle is sorted by checking only two of its dimensions. To fulfill tighter specifications and meet highest efficiency demands at high feed rates the unique Rotex screening motion combining the Giratory motion at the product inlet combined with a Reciprocating motion at the product outlet or overflow allows to meet the highest expectations: in accuracy and efficiency at high feed rates for an economical production. High Rotex quality screening means bigger capacity higher volume of product for sale, increased production, higher revenue. It also means reduced power consumption and production cost, overall this means higher and quicker ROI. 7. HOW DO ROTEX SCREENING MACHINES MEET YOUR NEEDS? WHY GYRATORYGYRATORY-RECIPROCATING MOTION IS SO EFFECTIVE • Long Stroke: positive spreading & conveying, effective ball action prevents blinding • Low Frequency: gentle on product and equipment ccurate separations • Horizontal Screen: accurate
The gyratory motion at the screen inlet and in the screen plane quickly spreads and fluidizes the feed and effects fast stratification and passage of undersize. The reciprocating motion towards the overflow of the screen allows the near size particles to pass and thus ensures the screening efficiency.
ROTEX MOTION GYRATORY & RECIPROCATING
Circular at feed end via eccentric shaft
Reciprocating at discharge end retained by draglink
ROTEX Screeners offer the best solution for accurate separations with highest efficiency at compatible screen loads .
8. FURTHER NEEDS AND THEIR ANSWERS -
-
Reduction in manpower for operation & service! >> Easy and fast screen change even with high product temperatures with one or two people only! >> High availability and temperature resistance of standard drives. >> Fast exchangeable drive cartridges. Stable production conditions! >> Continuously effective mesh cleaning by ball bouncing system. Machine suitable for future demands >> simple Atex certification. >> Plane screen operation allows to fulfill highest quality & efficiency demands. New Screening Solutions MEGATEX XD The High Capacity Screening Machine
Talk to us about the answers we provide. We have the answer to increase your production stroke revenue at reduced cost stroke investment. Our new Product Lines taking future developments into consideration are: • The MEGATEX XD (Above!) • The APEX (Below!)
New APEX Screener !
Apex picture
9. CONCLUSIONS -
Screening is an ÂŤ art Âť and it is based on proven experience, know how and testing. The screening motion and a screeners design are the key to success. Screening areas are not equivalent. Rotex Screening machines will either require less area (smaller equipment) or provide better screening efficiency and accuracy than competition. Applications (feed rate, accuracy and efficiency) determine the screener selection. The Quality of a fertilizer or mineral product will depend directly on the screener selection.