Improving Sugarcane Juice Quality: Benefits of The Ultrafiltration Technique

Description and Advantages

A SUGAR mill in the private sector and a national research institute have come together and successfully implemented a technique that helps in producing chemical free, nil sulphur, refined quality sugar.

The key ingredients in this technique. called ultrafiltration, are indigenous polymeric membrane modules. These membranes can withstand high temperatures and are only the second of their kind used in the sugar industry worldwide.

According to the Technology Information, Forecasting and Assessment Council (T1FAC), which supported the collaborative project, the only other similar attempt in the global sugar industry was by Koch Membrane Systems, US.

The sugarcane juice obtained from plantation crop Is purified by these membrane modules, which act as filters. The main advantages of this technique are improved recovery of sugar superior product quality and the fact that no chemicals are used.

The experiments establishing this ultrapurification technique using indigenous polymeric filters ere conducted at the Simbhaoli ar Mills Limited (SSML), in Ghaziabad district of Uttar Pradesh. The Tata Energy Research Institute (TERI), New Delhi, did the experimental work.

The process has been demonstrated on a 10 tonnes/hr industrial-scale pilot plant. The membranes specifically designed for the pilot-scale operations by Permionics, a Vadodara-based company, withstood continuous operations at 97 degrees C.

The technique should has great potential to help sugar manufacturers, especially of plantation while sugar, who have been facing the challenge of ensuring that the juice obtained through clarification is of consistently high clarity and low colour.

This poses a stiff challenge because of the wide variations in cane varieties, soil and growing conditions, climate and, above all, fluctuations in the manufacturing process itself, leading to variations in the juice characteristics, according to TERI.

To overcome this problem, membrane-based filtration methods, such as microfiltration and ultrafiltralion, are being tried out. TERI, with funding from the TIFAC under the 'Sugar Technology Mission' initiative, took up the demonstration project at Simbhaoli Sugar Mills Ltd, which was keen on evaluating ultrafiltration For the purification of sugarcane juice in the manufacture of plantation white sugar.

According to the project implemented by TERI and SSML, ultrafiltration trials for three successive crushing seasons beginning November 1997 were carried out at the Ghaziabad mill. The juice obtained had an additional purity of 0.74 units compared to the output using the conventional limingsulphitation process.

The other advantages claimed by the team consisting of Drs M. Balakrishnan and A. M. Ghosh of TERI, and Messrs S. N. Misra, N. C. Sharma and P. Ranga Rao of SSML, were a ten-fold improvement in juice clarity and a near 60 per cent reduction in colour. The process itself leads to a drastic cut in the inorganics (iron, silica, manganese and zinc) content" in the juice.

In short, the TERI-SSML-TIFAC initiative promises to provide an opportunity for the Indian sugar industry to develop a process for the direct production of chemical free refined quality sugar without going in for sugar refining techniques.

They suggest long-term trials and a commitment from the sugar industry to establish the reliability of this technique in the existing environment. A majority of the sugar mills in the country today use the double-sulphitation technique to produce plantation white sugar, which needs upgradation to produce international grade sugar, according to T1FAC.

Towards this end TIFAC, through its sugar technology mission, helped another private sugar factory in Barabanki village on the outskirts of Lucknow in Uttar Pradesh. DSM Sugar was extended a soft loan (6 per cent per annum) of Rs 474 lakh from the Sugar Development Fund (SDF).

Consequently, in the upgradation project minor changes to the existing machinery were made and a combination of phosphofloatation process for clarification, filtration and decolourisation deployed to produce sugar with nil sulphur and low ash content.

The double sulphitation process used by the sugar mill was replaced to produce raw and refined sugar of export quality and to meet the demands of the domestic pharmaceutical and beverage industries.

In the quest for providing technology inputs to produce sugar of international standard, TIFAC has been spearheading a Sugar Technology Mission (STM) since 1993. The five main thrusts of the mission are:

• Reducing sugar losses
  
• Energy conservation
  
• Superior product quality
  
• Minimisation of pollution v
  
• Value-addition to by-products.
  

The STM was started in close collaboration with the Department of Food and Public Distribution, It is one of the first instances when a socio-economic ministry decided to work closely with the science ministry for improvement in technical efficiency of a large industry.

Having already achieved several incremental technological developments, which are being implemented by the Indian sugar mills, the STM will, during the Tenth Plan period, focus on replication of select technologies already evaluated on a plant scale. It would prepare schemes for technology upgradation of 15-20 sugar factories for achieving multiplier effect.

In the past few years it has taken up 27 sugar factories for technological upgradation and helped prepare detailed schemes for the purpose. It has evaluated a number of modern technologies and extended financial, techno-managerial support to 19 new technologies for their evaluation.

Source: Business Line, 26 sep. 2001