Studies On Reduction Of Ice Usage In Dyes Industry

Abstract

The present study discusses the process change for the production process of reactive orange 13,dye to reduce or eliminate the usage of ice by developing feasible options using equipment modi cation and technology change from the Cleaner production tools. This Dye is obtained by coupling of diazotised meta-anilic acid with cynurated J-acid. The diazotization of meta-anilic acid is carried out by conventional method and coupling is carried out at pH 6.2 to 6.8 and temperature is maintained below 10°C. The most important method for the preparation of diazonium salts is treatment of aromatic amines such as aniline with nitrous acid. Usually the nitrous acid is generated in situ (in the same ask) from sodium nitrite (NaNO2) and mineral acid (generally HCl). In aqueous solution diazonium salts are unstable above +5 °C; the -N+ N- group tends to be lost as N2(nitrogen gas). This is the reason why ice is used in the reactions throughout the production process. Due to usage of ice there is the additional load on e uent treatment plant of the industry and the aditional e uent generated which in turn raises the environmental impact of the industry. The present study shows how the additional e uent is generated and some options to reduce ice. In this study two options were discussed namely: 1) Energy ball and 2)Flooded refrigeration system.A miniature ooded refrigeration system was conceptualised, designed and manufactured with a reactor on a skid.The main aim was to carry out the reactions steps with small volume of reactants and without the addition of ice inside the reactor.Four sets of experiments were performed under di erent reaction conditions and results showed a decrease of approximately 50% in the volume of e uent generated at the end of the last step.