Cation asphalt emulsion-coated modified low-rank coal and method for preparing coal-water slurry employing same

Abstract

The invention discloses a method for coating and modifying low-rank coal with a cation asphalt emulsion. The method comprises the steps of removing internal water of the low-rank coal under the microwave action until the mass of pulverized coal is constant, and then carrying out hole sealing and surface coating modification on the pulverized coal by adopting cation emulsified asphalt as a surface modifier, wherein the obtained modified low-rank coal can be used for preparing coal-water slurry. The method has the advantages of being small in modifier dosage, uniform in covering and significant in effect, the modified pulverized coal is low inrehydration rate, the hydrophobicity is increased, the preparation of high-concentration coal-water slurry by using a commercial dispersing agent is facilitated, and the rheological property and the stability of a slurry body of the coal-water slurry can be improved.

Description

technical field [0001] The invention belongs to the technical field of lignite application and relates to its surface modification, in particular to a cationic asphalt emulsion-coated modified low-rank coal and a method for preparing coal-water slurry. Background technique [0002] Coal-water slurry is a new technology that replaces oil with coal, which emerged in the 1970s and 1980s due to the shortage of oil. Coal water slurry is a new type of coal-based clean and environmentally friendly fuel. It is a solid-liquid two-phase suspension dispersion system prepared by a certain process from about 60-70% coal, 30-40% water and a small amount of additives. , has the same fluidity and stability as oil; it can be pumped, atomized and stably ignited; its calorific value is about half that of fuel oil. my country's development of coal water slurry technology is of great significance. [0003] CWS with industrial application value should have high concentration, low viscosity, goo...

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Problems solved by technology

[0004] In order to overcome the shortcomings of high water content in low-rank coal in the prior art and easy reabsorption of water after dehydration and upgrading, the purpose of the present invention is to provide a cationic bitumen emulsion-coated modified low-rank coal and its preparation method for coal-water slurry The method uses microwave technology to reduce the porosity and internal water content; because the oxygen-containing groups such as carboxyl groups on the surface of low-rank coal and the inorganic minerals such as carbonate and silicate on the surface of coal particles are all electronegative , the present invention uses cationic asphalt emulsion with positive charge, good film-forming performance and strong covering power to coat and modify low-order coal particles, and seal the pores on the surface of coal particles to prevent the quality of the coal after drying. Particles re-adsorb water to reduce its reabsorption of free water and improve the hydrophobicity of the coal surface, so that the low-rank coal that is difficult to slurry presents a surface strong hydrophobicity similar to high-rank coal, improving its coal-water slurry The fluidity and the stability of the slurry can make the dehydrated coal particles have the characteristics of greatly reduced porosity, improved hydrophobicity, low reabsorption rate of coal powder to free water, less dosage, uniform coverage, high efficiency and economy, etc. At the same time, commonly used naphthalene sulfonate and lignin salt can be used as dispersants, thus becoming an effective method for preparing high-concentration coal-water slurry by improving low-rank coal