阅读说明：本技术 干法重介质流化床分选机智能控制方法 (Intelligent control method for dry-method dense medium fluidized bed separator ) 是由 董良 赵跃民 任永鑫 王光辉 周恩会 段晨龙 于 2020-04-20 设计创作，主要内容包括：本发明公开了一种干法重介质流化床分选机智能控制方法,属于干法重介质流化床选煤技术领域。该方法包括以下步骤：风机供风使床层流化；根据原煤可选性曲线估算床层初始密度；检测床层磁性物含量,得出实时床层密度,根据与初始密度值的偏差分析结果,对床层密度进行调节；分选过程中可调节介质添加量及刮板排料速度以维持床层高度的稳定；原煤在分选机中经过分选得到精煤产品；检测精煤产品灰分,与目标灰分进行比较,若产品灰分与目标灰分差异超过预期,则对床层密度进行调节。本发明能够调节分选过程中介质添加量和刮板排料速度,维持床高稳定；依据原煤及产品性质对分选密度进行调节,具有智能化程度高的优点。(The invention discloses an intelligent control method for a dry-method dense medium fluidized bed separator, and belongs to the technical field of dry-method dense medium fluidized bed coal separation. The method comprises the following steps: the bed layer is fluidized by the air supplied by the fan; estimating the initial density of a bed layer according to the raw coal selectivity curve; detecting the content of magnetic substances in the bed layer to obtain the real-time bed layer density, and adjusting the bed layer density according to the analysis result of the deviation from the initial density value; the addition amount of the medium and the discharge speed of the scraper can be adjusted in the sorting process to maintain the stability of the bed height; the raw coal is separated in a separator to obtain a clean coal product; detecting clean coal product ash, comparing with target ash, and adjusting bed density if the difference between the product ash and the target ash exceeds expectation. The invention can adjust the addition amount of the medium and the discharge speed of the scraper in the separation process and maintain the high stability of the bed; the sorting density is adjusted according to the properties of raw coal and products, and the method has the advantage of high intelligent degree.)

1. An intelligent control method for a dry-method dense medium fluidized bed separator is characterized by comprising the following steps: the method comprises the following steps:

controlling a fan to blow airflow into a bed body to fluidize the bed layer, and controlling the air pressure and the air quantity to maintain stable when the pressure drop fluctuation of the bed layer is stable; estimating initial bed density according to selectable curve of selected raw coal

Step two, detecting the content of the magnetic substance in the bed layer, and calculating the real-time bed layer densityAnd the initial bed densityComparing, and regulating the medium adding valve according to the comparison resultAdding a medium into the separator;

thirdly, controlling and adjusting the discharging speed of the scraper and the addition amount of a medium, and maintaining the stability of the bed layer height; the raw coal is separated in a separator to obtain a clean coal product;

and step four, detecting the product ash content of the cleaned coal product obtained by sorting in real time, comparing the product ash content with the target ash content of the cleaned coal product, and adjusting the initial bed density if the difference between the product ash content and the target ash content exceeds the expectation.

2. The intelligent control method of the dry method dense medium fluidized bed separator as claimed in claim 1, wherein: in the second step, according to the comparison result of the real-time bed density and the initial bed density, a medium adding valve is adjusted, and a medium is added into the separator, wherein the method specifically comprises the following steps:

calculating real-time bed densityAnd initial density valueDeviation of (2)

If D is₁≤A₁Showing that the deviation satisfies the expectation, no adjustment of the bed density, A₁Is a density deviation threshold;

if D is₁>A₁And isAdding a circulating medium into the separator to reduce the density of the bed layer;

if D is₁>A₁And isAdding magnetite powder into the separator to increase the density of the bed layer;

the circulating medium is a magnetite powder mixture which is discharged along with the separation product and does not undergo magnetic separation and contains fine-grain coal slime.

3. The intelligent control method of the dry method dense medium fluidized bed separator as claimed in claim 1, wherein: in the third step, the discharging speed of the scraper and the addition amount of the medium are controlled and adjusted to maintain the stability of the bed layer height, and the method specifically comprises the following steps:

obtaining real-time bed height H_tCalculating the height H of the bed layer_tAnd setting a height value H₀Deviation D of₂＝|H_t-H₀|；

If D is₂≤A₂Showing that the deviation satisfies the expectation, without adjusting the bed height, A₂Is a height deviation threshold;

if D is₂>A₂And H_t>H₀The material discharging speed of the scraper is improved, and simultaneously, the addition amount of a medium is reduced, and the height of a bed layer is reduced;

if D is₂>A₂And H_t<H₀The material discharging speed of the scraper is reduced, the addition amount of the medium is increased, and the height of the bed layer is increased.

4. The intelligent control method of the dry dense medium fluidized bed separator according to any one of claims 1 to 3, characterized in that: in the fourth step, the product ash detected in real time is compared with the target ash of the clean coal product, and the initial bed density is adjusted according to the comparison result, specifically as follows:

calculating real-time clean coal product ash Ad_tTarget ash content Ad with clean coal product₀Deviation D of₃＝|Ad_t-Ad₀|；

If D is₃≤A₃Showing that the deviation satisfies the expectation, without adjusting the initial bed density, A₃Is an ash deviation threshold;

if D is₃>A₃And Ad_t>Ad₀Reducing the initial bed density, i.e. increasing the addition of circulating medium and reducing the addition of magnetite powderAn amount; if D is₃>A₃And Ad_t<Ad₀Increasing the density of the initial bed layer, namely increasing the addition of magnetite powder and reducing the addition of circulating medium; the circulating medium is a magnetite powder mixture which is discharged along with the separation product and does not undergo magnetic separation and contains fine-grain coal slime.

Technical Field

The invention belongs to the technical field of dry-method dense medium fluidized bed coal separation, and particularly relates to an intelligent control method for a dry-method dense medium fluidized bed separator.

Background

A dry-method heavy-medium fluidized bed is a high-efficiency dry-method separation technique which applies the gas-solid fluidization technology to the field of coal separation, and fine particle materials (such as magnetite powder) are used as a heavy bed layer to form a gas-solid two-phase suspension with certain density and height under the action of uniform ascending airflow, coal particles entering a separator are layered in the bed layer according to the density, clean coal floats on the surface of the bed layer, and gangue is settled at the bottom of the bed layer, so that the separation of the coal is realized.

The key of the dry method dense medium fluidized bed coal preparation is the bed density of the fluidized bed. In the separation process, raw coal can bring fine coal slime into the raw coal, and a certain amount of secondary coal slime can be generated in the separation process. The fine coal slime can widen the particle size distribution of particles in the bed in the fluidized bed, has the effect similar to that of a lubricant, is beneficial to improving the fluidization quality, but the excessive fine coal slime in the fluidized bed can cause the density of the bed to be reduced, and is not beneficial to the uniformity and stability of the density of the bed. Therefore, the bed density needs to be monitored, and high-density magnetite powder needs to be supplemented in time to maintain the uniform and stable bed density.

The bed height is also one of the important factors influencing the coal dressing effect of the dry-method heavy-medium fluidized bed. The air flow enters the bed layer through the air distribution plate in a micro-bubble mode, bubbles meet and grow in the ascending process, the higher the bed layer is, the larger the bubbles are, the stronger the disturbance effect on the bed layer is, and the stability of the bed layer is not facilitated; in addition, when the bed layer is too high, the heavy product in the bed layer sinks for a long time, so that the separation effect is influenced; when the bed layer is too low, the light products are lower than the conveying scraper and cannot be discharged, and the sorting process is influenced. The height of the bed of the fluidized bed is an important parameter and must be controlled within a suitable range.

In order to normally carry out the dry method dense medium fluidized bed coal dressing and sorting process, the uniform and stable height and density of the bed layer must be ensured. The current automatic control system of the dry method dense medium fluidized bed separator measures the bed density and height, inputs the measured signal into a computer for analysis and processing, and the computer adopts a control method to output an adjusting signal to an adjuster to adjust the density and the bed height. The method has high measurement precision and convenient operation and use, realizes the high automatic control of the classification precision of the dry method dense medium fluidized bed, and still has problems. Firstly, disturbance factors such as disturbance of air flow, movement of bubbles, collision of particles and the like can cause fluctuation to bed pressure, the bed pressure is unstable, and a pressure drop signal detected by a sensor is in change all the time; and the second is lack of necessary monitoring on the properties of the raw material coal, the properties of the selected products and the like.

Disclosure of Invention

The purpose of the invention is as follows: aiming at the problems, the invention provides an intelligent control method for a dry-method dense medium fluidized bed separator, which aims to solve the problem of low intelligent control degree in the current production and improve the coal separation quality.

The technical scheme is as follows: in order to realize the purpose of the invention, the technical scheme adopted by the invention is as follows: an intelligent control method for a dry-method dense medium fluidized bed separator comprises the following steps:

controlling a fan to blow airflow into a bed body to fluidize the bed layer, and controlling the air pressure and the air quantity to maintain stable when the pressure drop fluctuation of the bed layer is stable; estimating initial bed density according to selectable curve of selected raw coal

Step two, detecting the content of the magnetic substance in the bed layer, and calculating the real-time bed layer densityAnd the initial bed densityComparing, adjusting a medium adding valve according to a comparison result, and adding the medium into the separator;

thirdly, controlling and adjusting the discharging speed of the scraper and the addition amount of a medium, and maintaining the stability of the bed layer height; the raw coal is separated in a separator to obtain a clean coal product;

and step four, detecting the product ash content of the cleaned coal product obtained by sorting in real time, comparing the product ash content with the target ash content of the cleaned coal product, and adjusting the initial bed density if the difference between the product ash content and the target ash content exceeds the expectation.

Further, in the second step, according to the comparison result between the real-time bed density and the initial bed density, a medium adding valve is adjusted, and a medium is added into the separator, specifically as follows:

calculating real-time bed densityAnd initial density valueDeviation of (2)

If D is₁≤A₁Showing that the deviation satisfies the expectation, no adjustment of the bed density, A₁Is a density deviation threshold;

if D is₁>A₁And isAdding a circulating medium into the separator to reduce the density of the bed layer;

if D is₁>A₁And isAdding magnetite powder into the separator to increase the density of the bed layer;

the circulating medium is a magnetite powder mixture which is discharged along with the separation product and does not undergo magnetic separation and contains fine-grain coal slime.

Further, in the third step, the discharging speed of the scraper and the addition amount of the medium are controlled and adjusted to maintain the stability of the bed height, and the method specifically comprises the following steps:

obtaining real-time bed height H_tCalculatingHeight of bed layer H_tAnd setting a height value H₀Deviation D of₂＝|H_t-H₀|；

If D is₂≤A₂Showing that the deviation satisfies the expectation, without adjusting the bed height, A₂Is a height deviation threshold;

if D is₂>A₂And H_t>H₀The material discharging speed of the scraper is improved, and simultaneously, the addition amount of a medium is reduced, and the height of a bed layer is reduced;

if D is₂>A₂And H_t<H₀The material discharging speed of the scraper is reduced, the addition amount of the medium is increased, and the height of the bed layer is increased.

Further, in the fourth step, the product ash detected in real time is compared with the target ash of the clean coal product, and the initial bed density is adjusted according to the comparison result, specifically as follows:

calculating real-time clean coal product ash Ad_tTarget ash content Ad with clean coal product₀Deviation D of₃＝|Ad_t-Ad₀|；

If D is₃≤A₃Showing that the deviation satisfies the expectation, without adjusting the initial bed density, A₃Is an ash deviation threshold;

if D is₃>A₃And Ad_t>Ad₀Reducing the density of the initial bed layer, namely increasing the addition of a circulating medium and reducing the addition of magnetite powder; if D is₃>A₃And Ad_t<Ad₀Increasing the density of the initial bed layer, namely increasing the addition of magnetite powder and reducing the addition of circulating medium.

Has the advantages that: compared with the prior art, the technical scheme of the invention has the following beneficial technical effects:

the intelligent control method of the dry-method dense medium fluidized bed separator can detect and adjust the content of the magnetic substances in the bed layer in real time, and ensures the separation density; the addition amount of the medium and the discharge speed of the scraper can be adjusted in time, and the high stability of the bed in the separation process is maintained; the separation density is adjusted according to the properties of raw coal and products to form two closed-loop automatic control systems, namely a feed-forward system for adjusting coal separation parameters according to the properties of the raw coal and a feedback system for adjusting the coal separation parameters according to the properties of clean coal products, and the intelligent control system has the advantage of high intelligent degree.

Drawings

FIG. 1 is a flow chart of the intelligent control of the dry dense medium fluidized bed separator.

Detailed Description

The technical solution of the present invention is further described below with reference to the accompanying drawings and examples.

The flow of the intelligent control method of the dry-method dense medium fluidized bed separator is shown in figure 1, and the intelligent control method comprises the following steps:

controlling a fan to blow airflow into a bed body to fluidize the bed layer, and controlling the air pressure and the air quantity to maintain stable when the pressure drop fluctuation of the bed layer is stable; estimating the separation density, i.e. the initial bed density, from the selectivity curve of the selected raw coal

Step two, measuring the content of the magnetic substance in the bed layer through a magnetic substance content detector, and calculating the real-time bed layer densityAnd the initial bed densityComparing; adjusting a medium adding valve according to the comparison result, and adding a medium into the separator to enable the deviation between the real-time bed layer density and the initial bed layer density to meet the expectation; the method comprises the following specific steps:

calculating real-time bed densityAnd initial density valueDeviation of (2)If D is₁≤A₁Deviation meets expectations, bed density is not adjusted, A₁Is a density deviation threshold; if D is₁>A₁And isAdding a circulating medium into the separator to reduce the density of the bed layer; if D is₁>A₁And isAdding magnetite powder into the separator to increase the density of the bed layer; the circulating medium is a magnetite powder mixture which is discharged along with the separation product and does not undergo magnetic separation and contains fine coal slime, and the density of the mixture is low due to the fact that the fine coal slime is mixed, so that the density of a bed layer can be adjusted.

Step three, in the separation process, bed layer density is reduced due to the accumulation of coal slime content, high-density magnetite powder can be added into the separator, the height of the bed layer is changed after the magnetite powder is added, the discharging speed of the scraper and the addition amount of media are controlled and adjusted, and the stability of the bed layer height is maintained; the raw coal is separated in a separator to obtain a clean coal product; the method comprises the following specific steps:

obtaining real-time bed height H_tCalculating the height H of the bed layer_tAnd setting a height value H₀Deviation D of₂＝|H_t-H₀L, |; if D is₂≤A₂Deviation meets the expectation, bed height is not adjusted, A₂Is a height deviation threshold; if D is₂>A₂And H_t>H₀The material discharging speed of the scraper is improved, and simultaneously, the addition amount of a medium is reduced, and the height of a bed layer is reduced; if D is₂>A₂And H_t<H₀The material discharging speed of the scraper is reduced, the addition amount of the medium is increased, and the height of the bed layer is increased.

Detecting product ash content of the cleaned coal product obtained by sorting in real time through an online ash content meter on the cleaned coal conveying belt, comparing the product ash content with target ash content of the cleaned coal product, and adjusting the initial bed density if the difference between the product ash content and the target ash content exceeds expectation; the method comprises the following specific steps:

calculating real-time clean coal product ash Ad_tTarget ash content Ad with clean coal product₀Deviation D of₃＝|Ad_t-Ad₀L, |; if D is₃≤A₃Deviation meets expectations, no adjustment is made to the initial bed density, A₃Is an ash deviation threshold; if D is₃>A₃And Ad_t>Ad₀Reducing the density of the initial bed layer, namely increasing the addition of a circulating medium and reducing the addition of magnetite powder; if D is₃>A₃And Ad_t<Ad₀Increasing the density of the initial bed layer, namely increasing the addition of magnetite powder and reducing the addition of circulating medium.

The foregoing is a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, several modifications and variations can be made without departing from the technical principle of the present invention, and these modifications and variations should also be regarded as the protection scope of the present invention.