The thirty-first annual conference of the South African Sugar Technologists' Association was held at the M.O.T.H. Proceedings of the thirty-first annual conference of the South African Sugar Technologists' Association, held at the M.O.T.H.
THIRTY-SECOND ANNUAL SUMMARY OF CHEMICAL LABORATORY REPORTS
GENERAL
CANE QUALITY
The sucrose content of crushed cane during the period July-November 1956-57 was materially lower than that of the previous year or the average of the period 1945-1954. The sucrose content of the balance of the 1956-57 crop is also lower than that of the previous season and than the average of.
THE CHANGING VARIETAL SCENE TABLE E
This season's lower average sucrose content is therefore the combined result of lower sucrose content during the optimal period and low sucrose content during the remainder of the season. As a result of the steadily increasing area of sugar cane planted with N:Co.310, an increasing percentage had to be crushed in the first months of the season.
REGARDING THE PERFORMANCE OF THE MILLING TRAINS
Due to the combined effect of a lower total tonnage of sugar cane to be crushed and a slightly higher tonnage per week, the average number of weeks was further reduced. This shows that the combined crushing rate of all plants increased again, albeit slightly, last season.
GENERAL FACTORY PERFORMANCE
The corresponding performance figures are 36.1 percent and 50.9 percent absolute juice lost, respectively. The power of Darnall's tandem is, according to Royston's formula, 30.30 t.f.h. or 81 percent of the rating and achieved.
PURITY OF FINAL MOLASSES TABLE O
An overview of the purity of the final molasses in recent years is given in Table 0, while the undetermined losses in recent years are shown in Table Q. We do not know whether this increase is purely a consequence of the juice quality or whether the increased crushing speed also plays a role.
UNDETERMINED LOSSES
- LIME AND OTHER CLARIFYING AGENTS Eight factories applied the sulphitation process
Perk pointed out that the Royston formula did not strictly apply in the case where the size of the end rolls was increased. He agreed that some of the low purity could be due to the molasses jelly mixture.
ANNUAL SUMMARY OF AGRICULTURAL DATA FOR THE SUGARCANE CROP, 1954-55
However, the average yield of Zululand (including the Piet Retief district) was no less than 37.08 tonnes of cane per acre, which is an all-time record, and its best previous yield was 31.28 tonnes of cane per acre in . Hlabisa district had the next highest yield, 40.02 tonnes of cane per hectare, and Lower Umfolozi showed the biggest increase from the previous year.
HARVESTED AREA AND YIELD BY DISTRICT (FOR EUROPEAN GROWERS ONLY) Compiled from Union Census Department reports.
AN ANALYSIS OF THE JAVA RATIO
The only factor in favor of the Java Ratio as a cane evaluation tool is its convenience, ie. Antonowitz said the factory he was a reed in was rated with the help of S.J.M.
EXPERIENCES IN COMMISSIONING A BENT TUBE BOILER, SPREADER FIRED, BURNING BAGASSE OR COAL
Another thing that interfered with the operation of the boiler was the double-deck conveyor. He realized that this was harmful and coincidentally the pH of the water in the boiler was about 8 pH.
AN INDUCED DRAUGHT TYPE COOLING TOWER
52 and sprays upwards on a stainless steel umbrella which directs the water downwards in a fine spray, nozzle pressure is 3 p.s.i. Maintenance on this distribution system is negligible due to the unusually large size of the opening. However, the manufacturers claim that on very hot days the evaporative loss is as much as 1 percent of the water circulation rate per 10° of cooling; while on cool humid days it can be as low as 0.75 percent.
Figure 1 shows an exploded view of a typical Fluorine cooling tower, giving a clear indication of the components referred to in the text above.
SOME NOTES ON THE HYPERBOLIC COOLING TOWER AT MAIDSTONE
Periodic checks of the performance of the cooling tower are carried out and the following temperatures are observed: By comparing the temperature of water pumped into the plant (89.6°F) and river water (82.4°F), we find that 3.27 times as much water passed through the tower as was added from the river or alternatively 76.7 per cent of the total. Walsh asked how deep the water was in the ponds and noted that in the ordinary splash pond a head of only fifteen feet or more was required, while in cooling towers a considerable amount of power was required to raise the water to the top. of the towers.
Trewren said most of the water flowing through the cooling tower was in the Rossburgh pumps.
GROUP DISCUSSION ON THE PREVENTION OF ENTRAP- MENT AND THE CONSTRUCTION OF SAVE-ALLS
He said the entrainment consisted mainly of small sap particles and was dismayed to learn that in the second and third tubs of the quad at Amatikulu there was no baffle plate. A centrifugal type save-all designed by S.M.R.I, was fitted in the steam room of the third vessel. However, the principle of the Kestner save-all was incorporated into the save-alls designed by S.M.R.L. He followed this explanation with a demonstration of the semi-Kestner apparatus.
The first was the creation of entrainment and the second the recovery of the entrained sap.
REPORT ON HEIN-LEHMANN CONTINUOUS CENTRIFUGAL
The first sugar produced was pulverized by the diffuse action of a sieve. The viscosity of the molasses was much higher than that of the A sugars, as expected, but the reduction in sugar crushing was a surprise. In the case of A sugars, the re-effect of the sieve caused serious problems necessary for the successful purification of the mass.
However, to sum it up, the performance of the machine was not all that could have been desired as it was half too low and.
SOME OBSERVATIONS ON THE FILTERABILITY OF NATAL RAW SUGARS
69 It was at first thought that starch might be re-
Phosphates in the sugars examined do not appear to affect filtration to any marked degree
Although the degree of correlation between starch and the resistance to filtration in our tests is
It seems highly likely that wax and probably silica are among the more important impurities
The chloroform is evaporated and the weight of the residue multiplied by 10 to give wax in the sugar in mg./kg. He considered that the silica was present in the colloidal form and he thought that it was necessary to change it to the crystalline form. Alexander said that only the undissolved silica could precipitate in the mud.
Thumann said it was customary in the past to granulate on syrup at Umfolozi.
BONE CHAR IN SUGAR REFINING ITS USE AND TESTING
The method by which the coal is drawn from the bottom of the cooling pipe has been the subject of much ingenious inventive skill, and the basic problem is really quite complex. Make sure that the charcoal plate fits tightly around the tank's perimeter, and then cover the charcoal with water. Recall that the normal cycle length for bone char is an order of magnitude.
It is possible that Synthad has been improved since the Proceedings of the Technical Session on Bone Char published in 1955.
SOME NOTES ON THE EXTRACTION OF SUCROSE FROM CANE BY DIFFUSION
The equation also includes term d, i.e. average thickness of cane shavings in the direction of diffusion. It was shown that 72 percent of the pol in the residue is present in coarse pieces. 90 whether improvements in diffuser design can be expected to result in a significant improvement in the extraction of pol.
Before using the process, where preliming took place in a diffuser, they had problems with filters, but when using the diffusion process, they disappeared.
THE COMPOSITION OF SOUTH AFRICAN FINAL MOLASSES
O.M.% NONSUCROSE- NATAL FINAL MOLASSES 1955
CARBONATED ASH NATAL FINAL MOLASSES 1955
- Karl Fisher Method
The polarization of the samples was determined according to the method given in the Recommended Methods of Chemical Control, page 29. 150 ml of acid alcohol is added slowly and the solution is left overnight and then filtered through a Gooch crucible previously dried in the oven . Magnesia, however, appears to have been practically all removed by the alkaline reaction during liming, and the mass action of the large quantities of lime used in the carbonation process.
Antonowtiz said he was not fully aware of the importance of non-sugar in factories.
107 Mr. Rault asked whether the brix represented the
A FURTHER REPORT ON THE 'TRUE VACUUM PANS
When the conductivity drops to a value approximately equal to that of the upper limit of the metastable zone, the steam supply, immediately followed by the water supply to the condenser, is shut off. When the conductivity begins to drop again, the balancing water supply is turned on and the conductivity is maintained at the desired value for the rest of the coupling period. The results of the Illovo tests Table I. From the examination of this table it will be shown:. a) the sludge used came from different batches, but all from the same pebble mill;.
However, subsequent work in Tongaat and Illovo showed that the technique was not satisfactory, so the "steamless" technique was developed.
A CRITICAL COMPARISON OF METHODS OF TESTING FOR RESISTANCE TO MOSAIC
Dick, who read the paper, explained that one aspect of selecting new varieties of cane consists of tests for resistance to certain diseases, including mosaic. Dick said that in other parts of the world at least two other aphids have been shown to be capable of transmitting mosaic. 281 was not immune, but eventually it was released and was one of the most important varieties in the industry, and it was many years before any signs of mosaic were found in it.
He wondered if it was possible that in one case where the disease was susceptible, it was due to a different strain of the disease.
THE CONTROL OF WEEDS BY CHEMICALS
THREE EXPERIMENTS CARRIED OUT BY THE TONGAAT SUGAR COMPANY LTD
This late weed growth was obviously to the disadvantage of the pre-emergent treatments as will be seen later. On this basis, the results of the experiments are recorded in tables I, II and III, together with the cost of each treatment. However, the figures are accurate enough to give an idea of the economics of each treatment.
T h i s showed that while the chemicals applied had no effect on shoot number, they certainly affected cane growth at eight weeks to varying degrees.
SUCCESSFUL WEED CONTROL IN DRY AREAS
OBSERVATIONS AND RESULTS WITH WEEDKILLERS AT ILLOVO
It was of utmost importance that weed control occurred early in the life of the crop. It was now known that complete elimination was not possible or necessary, but control in the early stages of cane growth was. Stewart said the terrain in Natal meant it was not possible to use anything other than a knapsack spray on most pitches.
Material distribution and droplet size, for example, had a major effect on application efficiency.
FERTILIZER RESPONSES
The average response to nitrogen in cane plants in TMS was:. sulfate is equal to 5.58 tons of cane per hectare. sulfate is equal to 7.45 tons of tin per hectare. In the opinion of the writer, these are certainly not for any noticeable residual effect of nitrogen to plant cane. It is quite clear, therefore, that in the experiments treated here, the response to n i t r o g e n in ratoon is much better than in cane plants.
As in the case of nitrogen, potash responses are better in ratoons than in plant cane.
RECENT DEVELOPMENTS IN SUGARCANE BREEDING AND THE PRESENT VARIETY POSITION IN NATAL
The seedlings of the two crosses, although planted in the same field, were kept separate. If N:Co.310 does not deteriorate, it is unlikely to be replaced by N:Co.376 in the best areas, but it may be displaced in some of the less fertile areas. Further field checks were carried out in the area and the disease was found to be present on a number of surrounding farms.
In the mild phase of the disease, these stripes do not develop further than the intersection of the leaf blade with the leaf sheath.
GUMMING DISEASE OF SUGARCANE IN NATAL
The southern coast has been found remarkably free of the disease, as has the Pongola area. The presence of gum disease in such a large part of the industry tends to preclude eradication as a means of controlling the disease. The disease is maintained by the continuous reinfection of crops, although these are little affected by the infection.
Note the pockets formed by the action of the bacteria on the softer parts near the growing point.
