阅读说明：本技术 一种判别原煤流动性的方法 (Method for judging flowability of raw coal ) 是由 刘家利 姚伟 张喜来 屠竞毅 方顺利 李兴智 李炎 于 2021-07-12 设计创作，主要内容包括：本发明公开了一种判别原煤流动性的方法,包括如下步骤：1、按照《GB/T 211煤中全水分的测定方法》和《GB/T 212-2008煤的工业分析方法》测试得到原煤的全水分M-(t)和空干基水分M-(ad)；2、计算煤样的外水分M-(f)；3、根据原煤的全水分计算煤样的最高允许外水分M-(fy),M-(fy)＝0.741M-(t)-0.87；4、比较煤样的外水分和最高允许外水分,当煤样的外水分低于最高允许外水分时,煤样的流动性良好,反之,煤样的流动性较差,有堵煤风险。本发明刚发充分考虑了外加水分(喷淋、雨雪)对原煤流动性的影响；和电厂实际运行效果更为接近,具有较高的工业应用价值。(The invention discloses a method for judging the flowability of raw coal, which comprises the following steps: 1. testing and obtaining the total moisture M of the raw coal according to a GB/T211 coal total moisture determination method and a GB/T212-2008 coal industrial analysis method t And air-dried basis moisture M ad (ii) a 2. Calculating the external moisture M of the coal sample f (ii) a 3. Calculating the maximum allowable external moisture M of the coal sample according to the total moisture of the raw coal fy ，M fy ＝0.741M t -0.87; 4. and comparing the external moisture of the coal sample with the highest allowable external moisture, wherein when the external moisture of the coal sample is lower than the highest allowable external moisture, the fluidity of the coal sample is good, otherwise, the fluidity of the coal sample is poor, and the coal blockage risk exists. The invention takes the influence of external moisture (spraying, rain and snow) on the flowability of the raw coal into full consideration just before the start; the method is closer to the actual operation effect of a power plant and has higher industrial application value.)

1. A method for judging the flowability of raw coal is characterized in that: the method comprises the following steps:

the first step is as follows: testing and obtaining the total moisture M of the raw coal according to a GB/T211 coal total moisture determination method and a GB/T212-2008 coal industrial analysis method_t% and air-dry basis moisture M_ad％；

The second step is that: calculating the external moisture M of the coal sample_f％；

The third step: calculating the maximum allowable external moisture M of the coal sample according to the total moisture of the raw coal_fy％；

M_fy＝0.741M_t-0.87

The fourth step: and comparing the external moisture of the coal sample with the highest allowable external moisture, wherein when the external moisture of the coal sample is lower than the highest allowable external moisture, the fluidity of the coal sample is good, otherwise, the fluidity of the coal sample is poor, and the coal blockage risk exists.

Technical Field

The invention relates to the technical field of determination of fluidity of coal for power, in particular to a simple method for determining the fluidity of raw coal, which is suitable for coal for power.

Background

The raw coal hopper is an important device for storing, feeding and conveying coal in a power plant, and when the raw coal is poor in flowability, strong in binding power and rich in impurities, the raw coal hopper and a coal dropping pipe are easy to be bound and blocked, and even coal breakage and fire extinguishment are caused in serious conditions. The factors of coal influencing the fluidity of raw coal are mainly moisture, pressure and viscosity, and the existing research results show that: with the increase of the external moisture of the raw coal, the dynamic repose angle is increased and the fluidity is deteriorated. The theory of utility boiler (rope) published by the Chinese electric power publishing company shows that the external moisture M is_fWhen the coal conveying rate is less than or equal to 8 percent, the coal conveying operation is normal, M_f>When 12%, safe operation is difficult. The research results of 'the influence of different water contents and pressures on the flow characteristics of the raw coal particle system' published by gorgeous pores et al show that when the external water content M is_fWhen the content is more than 8%, the green coal hopper of the power plant is easy to generate a shed blockage phenomenon; when the external moisture M_fWhen the content of the coal particles reaches about 13%, the adhesive force among the raw coal particles is increased, and the overall fluidity is easily deteriorated. The overall conclusion is similar.

Through statistical analysis of coal quality data of typical domestic coal types, the fact that the external moisture and the total moisture of raw coal have strong correlation is found, and generally, the higher the total moisture of the raw coal is, the higher the external moisture of the raw coal is. Through actual research of power plants, most power plants including high-moisture lignite power plants have the problem of blockage of a coal conveying system and a coal dropping pipe, and generally, in rainy and snowy days, a coal pile is soaked by rain and snow. When the power plant adopts a closed coal yard, the phenomena are greatly reduced, and the influence of external moisture on the flowability of raw coal is large. Therefore, it is unreasonable to use the same standard to judge the fluidity of different coal types.

Disclosure of Invention

In order to overcome the defects of the prior art, the invention aims to provide a method for judging the flowability of raw coal, which has the effect closer to the actual operation effect of a power plant, has higher industrial application value and is suitable for coal for power.

In order to achieve the purpose, the invention adopts the following technical scheme:

a method for judging the flowability of raw coal comprises the following steps:

the first step is as follows: testing and obtaining the total moisture M of the raw coal according to a GB/T211 coal total moisture determination method and a GB/T212-2008 coal industrial analysis method_t(%) and air-dry basis moisture M_ad(％)；

The second step is that: calculating the external moisture M of the coal sample_f(％)；

The third step: calculating the maximum allowable external moisture M of the coal sample according to the total moisture of the raw coal_fy(％)；

M_fy＝0.741M_t-0.87

The fourth step: and comparing the external moisture of the coal sample with the highest allowable external moisture, wherein when the external moisture of the coal sample is lower than the highest allowable external moisture, the fluidity of the coal sample is good, otherwise, the fluidity of the coal sample is poor, and the coal blockage risk exists.

Compared with the prior art, the invention has the following advantages:

the invention has the advantages that the evaluation method is simple and convenient; secondly, the influence of different coal types and different total moisture on external moisture is fully considered, and the discrimination method is more scientific and reasonable; influence of external moisture (spraying, rain and snow) on the flowability of the raw coal is fully considered; and fourthly, the actual operation effect of the power plant is closer, and the industrial application value is higher.

Detailed Description

The present invention will be described in further detail with reference to examples.

The invention discloses a method for judging the flowability of raw coal, which comprises the following steps:

the first step is as follows: testing and obtaining the total moisture M of the raw coal according to a GB/T211 coal total moisture determination method and a GB/T212-2008 coal industrial analysis method_t(%) and air-dry basis moisture M_ad(％)；

The second step is that: calculating the external moisture M of the coal sample_f(％)；

The third step: calculating the maximum allowable external moisture M of the coal sample according to the total moisture of the raw coal_fy(％)；

M_fy＝0.741M_t-0.87

The fourth step: and comparing the external moisture of the coal sample with the highest allowable external moisture, wherein when the external moisture of the coal sample is lower than the highest allowable external moisture, the fluidity of the coal sample is good, otherwise, the fluidity of the coal sample is poor, and the coal blockage risk exists.

Table 1 shows the results of the determination of the fluidity of coal samples with different water contents in China, where "block" indicates poor fluidity and the tendency of blocking of the coal conveying system and the coal chute, and "no" indicates no blocking risk or low blocking risk of the coal conveying system and the coal chute. As can be seen from table 1: firstly, according to the existing external moisture M_fThe method judges that all the lignite is poor in overall fluidity, but the actual operation condition of the lignite unit shows that the coal conveying system and the coal dropping pipe of most lignite power plants are not blocked in the rainy and snowy weather, the probability of blocking the coal conveying system and the coal dropping pipe is increased due to rising of external moisture in the rainy and snowy weather, and after the power plants adopt closed coal yards, the phenomenon is greatly reduced, and the influence of the external moisture on the fluidity of raw coal is large. The invention distinguishes that the fluidity of most lignite is good and is more consistent with the operation of an actual power plant, and shows that although the total moisture of lignite is higher, the highest allowable external moisture M is_fyThe external water content is higher, but the external water content needs to be in a reasonable range to ensure the fluidity of the raw coal; even if the lignite is the same, the influence of external moisture on the flowability of the raw coal is different, if the method is adopted, the flowability of the Baoqing lignite with the total moisture of up to 50 percent is judged to be better, and the flowability of the Baoqing lignite with the total moisture of 45.4 percent is judged to be poorer, mainly, the difference between the air-dry basis moisture of the Baoqing lignite and the air-dry basis moisture of the Baoqing lignite is larger, so that the external moisture exceeds the highest allowable external moisture. Similar situations exist in the discrimination of two different stone Ge coal. It can be seen that the invention fully embodies the external water content risingUp to a certain value will result in poor flowability of the raw coal.

Table 2 shows the result of determining the fluidity of the soft coal of northern Shaanxi in the same coal series, and shows that the external moisture M is present_fThe judgment method shows that most coal samples in the area are easy to generate shed blockage, but the actual power plant operation shows that most coal samples in the area have no problem of poor fluidity, and the judgment result of the invention shows that most coal samples have good fluidity, are consistent with the actual operation of the power plant, only have poor fluidity of the NaLin river coal, and are mainly related to the over-low air-dry basis moisture (obviously lower than other coal types) of the coal, so that the external moisture of the coal exceeds the highest allowable external moisture.

Table 3 shows the results of the determination of the fluidity of different coal slime, and it can be seen that the determination results of the prior art are consistent with the determination results of the present invention, and the fluidity is determined to be poor, so that the problem of blockage of the coal conveying system and the coal dropping pipe is likely to occur, and the results are consistent with the actual operation results.

TABLE 1 flowability judgment of typical coal samples in China

TABLE 2 determination of flowability of northern Shaanxi bituminous coal

TABLE 3 fluidity judgment of coal slime