Effective level control in milk of lime mixing vessel

As the sole processor of the UK’s beet sugar crop, British Sugar work in partnership with 3,500 growers and customers to deliver a world-class product that is made to the highest standards every day. Processing around eight million tonnes of sugar beet and producing up to 1.4 million tonnes of sugar each year, they are the leading producer for the British and Irish food and beverage markets. Sugar beet  processing is a complex and demanding process. To consistently produce highest quality product and maintain the lead in efficiency, requires continuous innovation and process enhancements.
One area, recently improved, at its Newark production site is the production and mixing of milk of lime. This is an essential formulation for use in sugar production when purifying the juice from beet or cane. Typically, 125kg of limestone is consumed in the production of one ton of sugar, so it is a significant process input. Sugar beet is sliced up and passed through a diffuser to extract the sugar juice. Lime, produced from calcium limestone, is used in the next stage of the production process. It is converted into milk of lime and this is used to capture and remove impurities in the juice of sugar beet. A high quality lime-water mixture is required in the sugar process to ensure an efficient, high quality sugar juice purification stage.
Most of the sugar-processing plants have their own lime kilns, and they require good, high purity limestone to burn. This ‘high calcium’ limestone is converted into quicklime in lime kilns, at a temperature of 900°C. To obtain milk of lime, the ‘calcined’ lime is mixed into water and it is during this process that an accurate, reliable level measurement ensures consistent production.