The background
Rallis India is a well-known and reputed player in the business of providing solutions to farmers. These solutions include agrochemicals, plant-growth nutrients, seeds and fertilisers.

 

Product P, a leading herbicide in Rallis’ portfolio, proved its position as a critical seller for the company, earning a turnover of about Rs67 million last year. This chemical has been highly successful in the European market and it has been registered as a safe product, primarily because it has no or very low levels of nitroso compound impurity.

 

For Rallis, there was an urgent need to make Product P completely safe in the interests of large-scale handling of the product, as the nitroso compound is known to impart mutagenicity. Another aspect of this product was its colour and the sedimentation of black particulates when dissolved in solvents. Customers in European countries had wanted the colour to be pale yellowish instead of dark brown and that the product be free from suspended black particulate matter (these create spray problems on the field).

 

In view of the growing demand for Product P in overseas markets, any improvements in quality would have a positive environmental impact, ensuring customer satisfaction and enhanced volume growth.

 

The innovation
It was necessary to improve the quality of the herbicide by removing the impurity through a safe and optimised process. A cross-functional team, which included Sebastian Almeida, Suhas Kodgule, Tapas Kumar Nandi, Anna Bobade and Chandrashekhar Gharat, was formed to make Product P free from impurity.

 

The team conducted trials in the laboratory using conventional processes. These proved to be ineffective and failed to satisfy quality requirements. When conventional methods failed, the team realised the need for unconventional solutions. They decided to go in for higher-temperature treatment to distil the nitroso compound from the product. A careful study was conducted by internal and external experts (because higher temperatures with nitroso compounds are a known explosion hazard). The operational safety with which the team conducted the tests was validated by accredited labs such as Intertek and Chilworth.

 

Initially, the team members studied the trends at higher temperatures before selecting the parameters to operate. At this point, they considered incorporating a catalyst which would react during the distillation process and decompose the impurities at a lower temperature, causing them to be released in a gaseous form. This innovative idea had never been attempted before at the operational level.

 

The team conducted 52 trials in all, using the learnings from each trial to improve the process. The trials were conducted in association with Technoforce at Nashik in Maharashtra, India.

 

Sixteen trials were conducted in an ‘agitated thin-film evaporator’. The very first trial at the desired high temperature saw a fire break out in the residue tank on account of pressurisation, followed by the bursting of the safety nozzle. Trials were then resumed at a lower temperature after analysing the cause behind this failure and taking the necessary precautions. However, it did not yield the desired results; the overall recovery rate was only 82 percent. The risk was found to be greater at temperatures higher than 275°C.

 

As a further improvement, short-path distillation was attempted at a safe temperature and 36 trials were undertaken. These yielded recovery rates ranging from 82 to 95 percent. The sedimentation was brought down from 5–6 percent to less than 1 percent. The colour was transformed to a brilliant orange, but the trials were only partially successful on the impurity content and mutagenicity test.

 

The payoff
Fifteen samples were checked randomly. Of these, 13 failed the test, resulting in a success rate of 14 percent. Inconsistent product recovery was another adverse consequence. Had the effort succeeded, Rallis could have potentially saved the equivalent of 262.2mt per annum in CO2 emissions. It would also have resulted in reduced safety hazards, improved process time cycles, reduced cost of manpower and consumables, ensured better housekeeping, and created an additional revenue of around Rs77 million. Impressed with the potential inherent in the innovation, the team is determined to tackle the problem afresh.