A special composite coal water slurry additive for coal gasification

Abstract

The invention relates to a special composite coal water slurry additive for coal gasification, which is mixed and prepared from the following components in percentage by weight: 30-75% of lignosulfonate, 10-45% of sulfonate formaldehyde condensate, 5-15% of polyethenoxy ether, 5-25% of phosphate, 0-5% of pH regulator and 0-2% of stabilizer. The components are proportionally prepared into a solid powder mixture or a water solution with arbitrary concentration, and are added into dry-basis coal powder to be uniformly stirred, wherein the additive on dry basis accounts for 0.4-1.0 wt% of the dry-basis coal powder. The finished product coal water slurry prepared from the additive has the advantages of high slurry concentration, low viscosity, favorable rheological property, high stability and wide adaptability to coal types.

Description

technical field [0001] The invention relates to a coal-water slurry additive, in particular to a cheap, efficient and cost-effective composite coal-water slurry additive specially used for coal gasification. Background technique [0002] Coal water slurry is a new type of coal-based fluid clean and environmentally friendly fuel prepared by physical methods, and it is also a new type of raw material that uses coal as raw material to produce syngas. It is made of coal (about 60%-70%) with a certain particle size, water (about 30%-40%) and a small amount of coal-water slurry additives through a certain processing technology. CWS additives are the key to the preparation of high-concentration CWS. A small amount of CWS additives are adsorbed on the coal-water interface, so that the hydrophobic coal particles are evenly dispersed in the water, so that the CWS has high concentration, low viscosity, and good flow. Good performance and stability, with industrial application value. ...

AI Technical Summary

Problems solved by technology

[0003] At present, domestic and foreign coal water slurry additives, according to their chemical composition, are: (1) various substituted naphthalene sulfonate condensates, which have the advantages of excellent wetting and dispersing performance, strong dispersion and viscosity reduction ability, and slurry Good fluid flow, wide application range, but poor slurry stability, easy to separate water and produce irreversible hard precipitation, and the price is high

(2) Lignosulfonate has the advantages of rich raw material resources, cheap price, easy access to raw materials, and good pulping stability. However, its raw materials are complicated, its performance is unstable, and its pulping performance is relatively poor, so it is difficult to meet the requirements of industrial applications.

(3) Humate, which has the advantage of being extracted from low-rank coals and has good dispersion performance, but it is sensitive to metal ions, easily forms precipitation, and has poor slurry stability

(4) Polycarboxylic acid series, which has the advantage of good fluidity and stability of the prepared coal-water slurry, but the price is relatively high. It is acceptable for preparing coal-water slurry for combustion, and the cost-effectiveness for preparing coal-water slurry for gasification is poor

(5) Polyolefin series, which has the advantage of having a high dispersion and stabilization effect on low-ash coal-water slurry, but it needs to strictly control the molecular mass and its distribution, and the price is high

Naphthalene-based dispersants have problems of poor stability and high cost in pulping, while other polycarboxylic acid series and polyolefin series are efficient but expensive, and the cost of pulping is high

Lignosulfonate CWS additives are cheap and have good pulping stability, but poor dispersion effect

[0005] At present, there are many kinds of coal-water slurry additives in use in my country, but the quality is uneven and the cost performance is not high. They are either high-efficiency and expensive, or cheap and poor in performance, and the slurry concentration is generally low (some even as low as 50%). Meet industrial application requirements

In addition, in the pulping system of the coal-water slurry gasification device, one or several parts of the gray water, distillation condensed water, methanol distillation raffinate, MTO purified water and MTO waste alkaline water of the gasification system are often added. Or completely replace the desalted water in the process, which greatly increases the difficulty of pulping in the pulping system of the gasification device (the concentration of coal-water slurry decreases by 3% to 5% under the same conditions as the same period of time), and it is difficult to prepare high-concentration coal-water slurry. The concentration of coal slurry used for gasification is less than 60%. When the concentration of coal slurry is increased by 1%, the effective gas of coal slurry gasification can be increased by 1.67%. However, as the concentration of coal slurry increases, the viscosity of coal slurry increases sharply and the fluidity becomes poor , poor industrial application value