The HVAC room comprising three blowers and two air-conditioning units.

New SRT refined sugar conditioning silo sets the bar


Bosch Projects, in conjunction with its technology partners in Thailand, recently developed a new short retention time (SRT) refined sugar conditioning silo, designed to significantly reduce conditioning time and capital investment expenditure.

The first installation of the Bosch Projects SRT silo — which commenced mid-2017 in the western cane-growing region of Thailand and was commissioned at the beginning of 2018 — has been designed to process 35 tons of refined sugar per hour.

Granular white sugar leaving a refinery requires conditioning to prevent lumping and caking in the final packaged product. The major advantage of this new SRT silo process over conventional conditioning of refined sugar, is the reduced residence time of 16 hours, compared to the standard period of between 65 and 72 hours.

The short retention time SRT refined sugar conditioning siloThe short retention time (SRT) refined sugar conditioning silo.

This new SRT silo, which is completely automated for continuous output of conditioned sugar to the packing station, comprises a sugar infeed conveyor system, dual air-conditioning plant and blowers, four silos, a silo discharge elevator, and a system for dust extraction.

The short retention time conditioning process, which operates in a batch sequence, makes use of three or four equally sized smaller silos. As one silo is being filled, another will be discharged and simultaneously, two silos will be undergoing conditioning phases that are staggered by eight hours. With the correct scheduling, this arrangement permits the silo to operate continuously, with two conditioning phases and two material transfer phases active at any one time.

Installation in progressInstallation in progress.

The key to SRT success is in the humidity and volume of air, which is introduced during the conditioning phase. The air passes through a filtration system before being dehumidified to a specific value and then transfers into the duty blowers. Downstream of the blowers, the air is cooled before being independently introduced into the two silos that are in the conditioning phase.

Bosch Projects designs and supplies a full range of equipment for the sugar industry, from the front-end cane preparation and juice extraction, through to processing, refining, and packaging.

“An important part of the company’s service to the sugar industry is in equipment design. The Bosch Projects team — which works closely with sugar growers, millers, and refiners around the world — has a thorough understanding of current trends in the industry and is able to identify exactly where opportunities exist, for future improvements in mechanical design,” explains Neil du Plessis, business manager: Sugar Equipment at Bosch Projects, part of the Bosch Holdings Group. “The company has developed advanced equipment designs by combining the latest technologies and manufacturing trends, whilst retaining the ‘tried and tested/proven technology’ principles favoured by the sugar industry.

The new SRT silo in the western cane growing region of Thailand was commissioned at the beginning of 2018The new SRT silo in the western cane-growing region of Thailand was commissioned at the beginning of 2018.

“By modernising the design of equipment to optimise efficiencies and enhance performance, the cost of sugar processing is reduced, productivity is improved, maintenance requirements are minimised, and the service life of every system is significantly extended.”