Getaz M.,Rushmore |
Sanders R.,Fives Fletcher Ltd
Zuckerindustrie | Year: 2011
In modern installations vertical cooling crystallisers are now preferred over traditional horizontal units because of the significant benefits they offer, which include larger volumes and smaller floor space, suitability for outdoor installation, higher cooling surface to volume ratios and a better ability to handle highly viscous massecuite, amongst others. Since the first vertical cooling crystallisers were introduced, nearly 40 years ago, there has been a steady increase in their unit size from initial volumes in the 50-200 m 3 range up to the present day where the most general unit size is now in the 300-400 m 3 range, with even larger units becoming increasingly common. Large crystallisers present some significant design challenges and a good modern vertical cooling crystalliser design requires a robust construction of heat exchange surface, stirrer and drive units coupled with features that promote good heat transfer characteristics and uniform massecuite flow patterns. Careful attention to cooling tube and stirrer arm design and configuration are needed to achieve this, whilst the use of modern planetary gearboxes and variable frequency controlled motor drive units can provide added benefits to boost both performance and reliability. How these design features are incorporated in a modern unit is explained, focusing on cane C massecuite duty and using the Fives Cail and Fives Fletcher units as an example.
Inskip S.T.,Fives Fletcher Ltd
International Sugar Journal | Year: 2010
Fives Cail has developed and improved its cane preparation technology to meet the requests of modern cane sugar and ethanol factories who either want to upgrade their factories or build new ones; the major concerns being investment, performance, energy and operation. Fives Cail now has more than 30 installations of the in-line shredder in Africa, Asia and the Americas, and has continually improved and developed the design to extend the range up to a capacity of 825 tonnes cane crushed per hour, while at the same time simplifying the original designs of feed drum, rotor, hammers and anvil plate and increasing the capacity for a given carrier width. The in-line shredder technology consists of two main pieces of equipment; a cane leveller (or carding drum) and the shredder assembly, which allows for a very simple and uncomplicated installation that can be either incorporated into an existing cane carrier or installed in a new one. Its construction is modular with a small footprint. The in-line shredder will process either whole stick or billeted (short) cane or any combination of the two, and can operate in all possible conditions including the preparation of washed cane, and also cane containing a high quantity of sand or rocks. All results shown have been obtained directly from the factories, either through official channels or from personal visits by Fives Cail personnel. As with all results collected under non-laboratory conditions, some approximation may be assumed; however, they tend to show fairly consistent figures. It can therefore be concluded that after several years of continual development and improvement, research and results show there are several genuine benefits, both direct and indirect, to be gained from incorporating the in-line shredder technology into a factory in order to upgrade the cane preparation performance. Benefits can be seen in terms of reduced installation costs, reduced maintenance costs, and reduced overall power consumption over more conventional cane preparation equipment.
Taylor M.,Fives Fletcher Ltd |
Getaz M.A.,Fives Fletcher Ltd
International Sugar Journal | Year: 2010
Boiling massecuite in a vacuum pan requires simultaneous regulation of its dissolved solids concentration, crystal content, consistency and supersaturation. A key challenge in pan boiling is measuring the necessary massecuite properties for controlling these parameters. Fives Fletcher has been supplying electronic sensors for vacuum pan crystallisation control for more than 25 years and has been at the forefront of the considerable developments that has taken place in the technology during this time. The paper reviews the developmental history of online sensors with specific emphasis on conductivity, radio frequency and microwave technology. Information on practical aspects of the use and application of these so-called 'brix' probes is presented. An evaluation of the current developments is also given and includes some recommendations for controlling both batch and continuous vacuum pans.