The Synthesis And Performance Research On Efficient Naphthalene Series Of Coal Water Slurry Dispersant

Coal water slurry(CWS) was a kind of new and clean coal fuel technology developed in the70s of the20’s century. Dispersant is the key factor of high concentration and high stability coal water slurry. β-naphthalene sulfonic acid sodium and formaldehyde condensate (Naphthalenesulfonate-formaldehyde condensate) are widely used in commercial CWS at present as they have the advantages of abundant of raw material, well coal water slurry stability.Firstly, the synthesis of this kind of surfactant was studied by sulfonation, decomposition, condensation and other steps, using technical naphthalene, sulfuric acid and formaldehyde as raw material. The synthetic process of producing Naphthalenesulfonate-formaldehyde condensate was introduced in this paper. Different matching proportion of naphthalene with water, naphthalene with formaldehyde, various reaction temperature and so on were tested to show the effect on the molecular weight of condensate. The function group of condensate and molecular weight were analyzed by infrade spectrum. The results showed that if mass ratio of naphalene with water was1:0.25, temperature was115℃, reaction time was60min, mol ratio of naphalene with formaldehyde was1:0.7, the condendate temperature was100-110℃, reaction time was6h, the molecular weight of condensate was4700.With shenhua coal as raw material, the dispersion properties of Naphthalenesulfonate-formaldehyde condensate were studied in the condition of coarse powder:fine powder was7:3, the concentration of coal water slurry was60%, the dosage of condensate was0.3%. The results showed that the condensates made by the optimum conditions were used in coal water slurry, the grade was A, the viscosity of the slurry was627mpa.s.Secondly, to increase the polymerization degree of condensate, some catalysts were used in the synthesis process of Naphthalenesulfonate-formaldehyde condensate, in the optimum conditions as stated before. Catalysts such as Fe2O3/SO42-,Al2O3/SO42-, TiO2/SO42-and Fe2O3-TiO2/SO42-were prepared by incipient-impregnation, and the properties of catalysts were characterized by infrared spectrum and TG-DTA. The results showed that Fe2O3/SO42-was the best catalyst to synthesize n-butyl acetate. The esterification of reaction which was catalyzed by superacid was respectively99.3%,86.4%,94.5%,95.9%. When mole ratio of acid to alcohol was1:1.4, amount of catalyst was0.6g, reaction time was2h. Then, catalyst Fe2O3/SO42-was used in synthesis process of β-naphthalene sulfonic acid sodium and formaldehyde condensate, the molecular weight of condensate was improved.At last, to enhance the dispersing ability and stability of the Naphthalenesulfonate-formaldehyde condensate, it was modified by sodium lignosulfonate. The function group of condensate was analyzed by infrared spectrum and the dispersing properties was characterized by the performance of CWS.