Method for modifying and tackifying low-rank coals

Abstract

The invention discloses a method for modifying and tackifying low-rank coals. The method comprises the following steps of: mixing low-rank coal materials, solvent water and a catalyst and putting the mixture in a high-pressure reactor; introducing a reducing gas mixture, adjusting the pressure of the high-pressure reactor, raising the temperature for reaction; and cooling the mixture to the room temperature after the reaction is completed and carrying out solid-liquid separation, wherein the solid product obtained by separation is modified tackified coal which can be used for coking. According to the method disclosed by the invention, the activity of the hydrogen generated by the reaction of water and CO is high, the coal modifying efficiency is high, the caking index G of the modified coals reaches 90 or higher, and so the low-rank coals can be used for coking after being modified. Moreover, the method is simple, the material source is wide, the coal modifying cost is low and the economic benefits are high.

Description

technical field [0001] The invention relates to a method for modifying and increasing viscosity of coal, in particular to a method for modifying low-rank coal to prepare coking coal. Background technique [0002] High-quality coking coal resources are increasingly in short supply, and low-rank coal reserves are relatively abundant, and the coking index G of coking coal is generally required to be above 60. If the low-rank coal is modified to improve the cohesiveness of these coals, it can be used Coking, which will fundamentally solve the problem of shortage of high-quality coking coal resources. [0003] The existing methods for coal modification and viscosification mainly include rapid heating treatment, hydrothermal treatment and hydrogenation plasticization. The purpose of these methods is to modify low-rank coal to improve its cohesiveness and coking property , partially or completely replace coking coal for coking. For example, Kato et al. reported "Effect of Rap...

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Problems solved by technology

These modification methods are relatively simple and have little environmental pollution, but they only increase the amount used in coking coal blending, and the caking property of the modified coal needs to be further improved before it can be used as coking coal

[0006] Available prior art, there is also CN102154049A disclosing "a method for preparing coking coal by upgrading low-order non-caking coal", which uses 30-90% of the quality of the petroleum fraction after catalytic hydrotreating to pulverized coal % compounding, adding catalyst, making coal slurry, and then adding the treated high-temperature coal tar into the coal slurry according to the amount of 5-40% of coal powder, mixing and adding to the reactor for hydrogenation reaction, the reaction temperature is 350-420 ℃, the residence time is 30-60min, and the system pressure is 9-16MPa. Finally, the reaction product is subjected to vacuum distillation to separate the solid modified coking coal. The solid product obtained by this method is G>75, which can partially replace coking coal for coal blending Coking, but this method first needs to be mixed with high-temperature coal tar before the reaction, and the product after the reaction needs to be separated by vacuum distillation to obtain modified coal, and the process is relatively complicated

CN101302455A also discloses "a method for plasticizing low-modified bituminous coal". In this method, low-modified bituminous coal is mixed with a hydrogenation solvent, ferric oxide is used as a catalyst, and the reaction atmosphere is hydrogen. The selected hydrogenation solvent is different from the former It is tetrahydronaphthalene, its dosage is 2.0-2.5 times of the quality of low metamorphic bituminous coal, the hydrogen pressure is 2-6MPa, the reaction temperature is 340-400°C, the residence time is 20-60min, the reaction product is cooled and then dried to obtain improved The viscosity index of natural coal reaches about 60, but tetrahydronaphthalene and hydrogen are used in the method, and the cost is high

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