ESTIMATION OF pH OF SUGAR CANE JUICES A . T HIGH TEMPERATURE
A Philips digital pH-meter (PW9422) equipped with a Philips high temperature pH-electrode (CH 85D-SD) and platinum 100 thermometer was used in the autocalibrate mode to standardise itself using 2 NBS-buffers (phthalate and borax solutions). The instrument automatically identifies each buffer and uses the current temperature to select the exact buffer value from its look-up table. Temperature compensation for electrode slope changes due to temperature changes was also automatic.
Analysis of factory performance figures as an aid to identifying sources of undetermined loss.
The South African sugar industry possesses arguably the best technical information systems in the global sugar industry. All factories in the country (as well as a number of affiliate member factories external to South Africa) provide accurate cross-checked figures on a weekly and monthly basis to the Sugar Milling Research Institute (SMRI), who collate the data and produce consolidated performance reports. This extensive database is of great value for benchmarking and evaluating performance and is already a useful resource for technologists. However, the potential exists to further increase the usefulness of the collected data by means of detailed analysis, as an aid to troubleshooting and for the ongoing monitoring of factory performance. The estimated undetermined loss for a factory is a key performance measurement and an important guide for production management. Due to inherent problems in the measurement of undetermined loss, making effective use of these measurements normally requires a high degree of processing knowledge, experience and judgement. Although a range of secondary measurements can be used to help identify sources of undetermined loss, these usually require extra flow measurements, sampling and specialist analyses. A new approach to trying to identify possible sources of undetermined loss is proposed. This involves comparing available process measurements with the predictions of a boiling house mass balance. Assumed loss streams are introduced into the boiling house mass balance and their magnitudes are adjusted to match the mass balance to factory performance figures. Details of this approach are presented.
AN EVALUATION OF SUCROSE INVERSION AND MONOSACCHARIDE DEGRADATION ACROSS EVAPORATION AT DARNALL MILL
High temperature exhaust steam (180 to 190'C) is used in the Kestner pre-evaporators at Darnall mill. Experiments were undertaken to determine the effectsof high steam temperatures and high retention times on sucrose and monosaccharide degradation. Gas chromatography was used to determine glucose, fructose and sucrose in and out of these vessels. Glucose losses were found to be negligible, and the glucose/brix and/or glucose/chloride ratios are sensitive indicators of inversion. Measured sucrose lossesacross the Kestners and evaporator tail were a function of retention time rather than steam temperature. Colour formation was noticeable, and was attributed to fructose degradation.