| China is one of the world’s coal producing superpowers, but the comprehensive utilization of coal resources is not high, the environmental pollution problem caused by coal combustion is increasingly serious at the same time. Therefore, how to efficient and environmentally friendly utilization of coal resources has aroused the attention of the experts and scholars. As a new generation of clean oil combustion and its high combustion rate and convenient transportation, Coal water slurry has attached great attention of the personage inside. Dispersant was an indispensable and important additive to the preparation of high concentration and low viscosity of coal water slurry, as the key factors which affected the performance and price of coal water slurry. The main function of it was to improve the pulp concentration and reduce the apparent viscosity of coal water slurry, while the stability of coal water slurry was enhanced. Starch reserveed abundantly in the nature, its characteristics of low cost, environmental protection and renewable had gradually become one potential research direction in the field of coal water slurry (CWS).Starch dispersant of coal water slurry was obtained by natural polymer modified starch, with the advantages of a wide range of sources, green environmental protection, high pulping stability etc. However, existing research was only limited to graft copolymerization and partial primary modification of starch. Although the graft copolymer of starch had good dispersing effects, the grafting monomer price was higher so that the cost of pulping increaseed.This paper studied from the chemical properties and dispersing agent action mechanism of corn starch, taking three sulfonic acid sodium ammonium (N (SO3Na) 3) as sulfonating agent, sodium hypochlorite as oxidant, prepared sulfonation-oxidation starch water coal slurry dispersant (SOS). Through FT-IR, 1H-NMR, GPC and XRD, this paper characterized and analyzed the molecular structure, molecular weight and distribution. Appling SOS to Binchang coal pulping and taking coal water slurry apparent viscosity as the reference, the optimum sulfonic acid groups determine the degree of substitution was 0.3, best carboxyl content of 0.41%. Optimum amount of SOS dispersant was 0.9%, the maximum slurry concentration could reach 67%, the apparent viscosity was 927.6 mPa-s, drainage ratio was 2.7% after seven days. While the maximum slurry concentration of naphthalene dispersing agent was only 66%, bleeding ratio was 4.1% after seven days.Using oxidation and acid degradation solution to pre-process degrade starch, taken H2O2-Fe2+ as the initiator, acrylic acid, sodium styrene sulfonate as monomer and through free radical polymerization reaction to make oxidized starch graft copolymer water coal slurry dispersing agent (OSSA) and acid solution of starch graft copolymer of coal water slurry dispersing agent (HSSA). Their structures of relative molecular quantity and distribution was characterized and analyzed by physical and chemical properties, infrared spectrum, nuclear magnetic resonance spectroscopy and gel permeation chromatography. Their application for Binchang coal slurry, inspected and contrasted the se two different degradation methods of coal water slurry apparent viscosity, rheology, stability, influence of the adsorption capacity and compared to the naphthalene dispersed agent. The results showed that OSSA had better effects on reducing viscosity and stabilizing to Binchang coal. OSSA optimum adding amount was 0.4%, maximum into slurry concentration could reach 67%, apparent viscosity was 906 mPa-s; slurry with obvious shear thinning flow characteristics; OSSA was monolayer adsorption on the surface of coal, saturation adsorption quantity was 4.35mg/g; slurry with high stability.Taken benzyl chloride as hydrophobic reagent, the mixed solution of isopropyl alcohol and water as solvent, hydroxyethyl starch and oxidized starch as the main chain, synthesized oxidations of benzyl starch (OBS) and benzyl hydroxyethyl starch (HBS) coal water slurry dispersant. The structure was characterized and analyzed by infrared spectrum, nuclear magnetic resonance hydrogen spectrum and thermogravimetric analyzer and so on. It was applied to Shenhua coal, investigated the optimum dosage and maximum slurry concentration of dispersant, and studied the stability, rheology, surface tension and dispersion mechanism. The results showed that the application performance of OBS was better than HBS. The optimum adding amount of OBS was 0.5%, the maximum slurry concentration was 65%, the apparent viscosity was 754mPa-s, the saturated adsorption amount was 3.75 mg/g; drainage ratio was 3.34% after seven days. |
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