FILTERABILITY OF RAW SUGARS - LABORATORY TESTS VERSUS REFINERY PERFORMANCE

The filterability of a raw sugar is one of its key quality parameters, and it has an important effect on refining. As yet we do not have a r ecognised method of measuring this property in a way that represents f iltration performance in a refinery. A study has been carried out on t he filtration characteristics of a number of raw sugars received at Ta te & Lyle's Thames Refinery. The filterability of the affined raw suga rs has been measured using a method that is a modification to the Nich olsen Horseley filtration test. These modifications are described. The filtration test has been carried out on both affined raw sugar, and o n the melter liquor produced from that raw. A similar filtration test was also carried out on the carbonatation liquor, and all three were c ompared. Thus filtration characteristics of the raw sugars, and the wa ys that they behave in the refinery have been studied. The applicabili ty of the test for a carbonatation refinery is discussed. The test wil l measure filtration problems caused by suspended solids, but will not indicate whether there will be problems due to starch. Starch will no t cause a filtration problem in the test method, but will upset carbon atation, hence causing a filtration problem.