BigPatents India

The present invention relates to an improved process for the production of naphthalene sulphonate formaldehyde condensate additive for coal-water slurry fuels. The main usage of the invention is in the preparation of high concentration coal-water slurry fuel achieving desirable flow property and stability. The process steps are: characterized in that sulphonation of naphthalene at a temperature in the range of 130-165oC, for a time period in the range of 2-8 hrs, condensing the resulting naphthalene sulphonic acid with formaldehyde, cooling to ambient temperature and neutralizing the condensation product with alkali metal hydroxide followed by drying to obtain naphthalene sulphonate formaldehyde condensate.