用于粗煤泥脫水脫泥滾筒篩的研制及其性能試驗研究
發(fā)布時間：2018-08-19 13:30
【摘要】：粗煤泥是在煤炭洗選加工過程中的一種伴生煤泥，這種煤泥粒度較小，大約在1mm左右，級別寬，顆粒形狀復雜，表面積大，持水性強，水分含量高，且在選煤廠中大量存在，能否有效的對這部分煤泥脫水脫泥并實現(xiàn)回收具有可觀的經(jīng)濟效益。近年來對粗煤泥獨立實施分選已經(jīng)成為一種既定工藝，但由于水力分選中粒度的影響，使得細粒物料的灰分總是大于粗粒物料，而現(xiàn)有的細粒篩分設備脫泥效果又不盡人意，導致粗煤泥精煤灰分偏高，亟需研究一種新型高效的粗煤泥分級脫水脫泥設備，提高粗煤泥的回收效果。 文章將滾筒篩應用在粗煤泥回收過程中的脫水脫泥上，試制了一種適用于處理煤泥水的滾筒篩，并在篩筒內(nèi)壁加設了螺旋導流葉片，而不是通過安裝傾角來出料。該滾筒篩主要是采用過濾的原理，將物料通過給料裝置給入到旋轉(zhuǎn)的篩筒中，粗顆�？焖俪两档胶Y筒內(nèi)壁，由于篩筒的轉(zhuǎn)動帶動內(nèi)壁沉降下來的料層傾斜上移并翻滾，使上層懸浮液所受的料層阻力顯著減小而快速透篩，未透篩的固體顆粒在重力和螺旋導流的推動作用下沿篩筒軸線方向出料。從而實現(xiàn)了濾液由篩縫流下，而料層由螺旋導流葉片軸向?qū)С觥?使用該滾筒篩對粗煤泥進行分級試驗，分別對操作參數(shù)（滾筒轉(zhuǎn)速和入料流量）和入料性質(zhì)（濃度和粒度）進行了相關(guān)試驗研究，探究其在不同工況下的脫水脫泥規(guī)律。結(jié)果表明滾筒篩用于粗煤泥脫水分級具有良好的效果，篩上產(chǎn)物含水量可達到30%以下，分級效率可達到80%以上。滾筒篩的轉(zhuǎn)速對脫水分級有很明顯的影響，一般轉(zhuǎn)速越高，脫水分級效果越好。入料流量也決定滾筒篩的轉(zhuǎn)速，流量越大，所需的轉(zhuǎn)速也越大。入料濃度對滾筒篩脫水和分級有不同的影響，，在入料濃度為30%時，脫水效果最差，低于或高于30%都會增強脫水效果；滾筒篩的分級效果是隨著入料濃度的升高逐漸減小的。入料粒度中，難篩粒與阻礙粒含量越多，篩分效果越差。 利用離散單元法軟件EDEM對滾筒篩的篩分過程進行仿真試驗研究。本次仿真試驗重在研究不同轉(zhuǎn)速下各粒級顆粒在滾筒篩內(nèi)的運動狀態(tài)及透篩情況，為了減少計算時間，對篩筒模型及顆粒模型進行了一定的簡化。通過對仿真試驗結(jié)果計算出的分級效率與實際試驗分級效率對比，其分級規(guī)律基本一致，均隨著轉(zhuǎn)速的增高，分級效率增大。通過對顆粒在滾筒篩內(nèi)的運動狀態(tài)分析，得出不同粒級在滾筒篩內(nèi)的運動狀態(tài)不同：粒度越小，滑落運動狀態(tài)時位置角越大，拋落運動狀態(tài)時拋落角也越大，反之，則位置角和拋落角均越�。浑S著轉(zhuǎn)速的增大，透篩面積會隨著轉(zhuǎn)動方向拓展，當轉(zhuǎn)速為0.91Nc時，幾乎在整個圓周方向均會透篩。通過對篩面上各粒級量的變化規(guī)律分析，得出粒級不同，螺旋導流葉片的推動作用不同，粒度越小，螺旋的推動作用越小，粒度越大，螺旋的推動作用則越大；通過對不同粒級顆粒透篩的分析，發(fā)現(xiàn)轉(zhuǎn)速越高，透篩越快，其中粒級越小透篩越容易。 文章從分別使用實際物料試驗與EDEM仿真試驗兩個不同方面對試制的滾筒篩進行了研究，得出了一些有用的結(jié)論，為指導滾筒篩的設計與優(yōu)化提供了一定的基礎。
[Abstract]:Coarse slime is a kind of associated slime in the process of coal washing and dressing. The slime has small particle size, about 1 mm, wide grade, complex particle shape, large surface area, strong water holding capacity, high moisture content, and exists in a large number of coal preparation plants. Whether it can effectively dehydrate and desliming this part of slime and achieve recovery has considerable economic benefits. In recent years, independent separation of coarse slime has become an established process, but due to the influence of particle size in hydraulic separation, the ash content of fine material is always greater than that of coarse material, and the desliming effect of existing fine particle screening equipment is not satisfactory, resulting in high ash content of coarse slime concentrate. Therefore, it is urgent to study a new type of high efficiency coarse slime separation. The stage dewatering and desliming equipment improves the recovery effect of coarse slime.
In this paper, the roller screen is applied to the dewatering and desliming of coarse coal slurry recovery process, and a roller screen suitable for the treatment of coal slurry water is trial-manufactured, and a spiral guide vane is added to the inner wall of the screen cylinder, instead of discharging through the installation of inclination angle. In the middle, the coarse particles settle rapidly to the inner wall of the sieve barrel, and because the rotation of the sieve barrel drives the material layer to tilt upward and roll over, the resistance of the upper suspension layer is significantly reduced, and the solid particles which are not penetrated through the sieve can discharge along the axis of the sieve barrel under the impetus of gravity and spiral diversion. The sieve is sewn down by the seams, and the material layer is derived from the axial direction of the spiral guide vane.
The drum sieve was used to classify the coarse coal slime. The operation parameters (drum speed and feed flow) and the feed properties (concentration and particle size) were studied. The results showed that the drum sieve had a good effect on the dewatering and classification of the coarse coal slime and the water content of the product on the sieve was good. The rotational speed of the roller screen has a significant effect on the dehydration and classification. The higher the rotational speed, the better the dehydration and classification effect. The feed flow rate also determines the rotational speed of the roller screen. The greater the flow rate, the greater the rotational speed required. When the degree of dehydration is 30%, the dehydration effect is the worst, lower or higher than 30% will enhance the dehydration effect; the classification effect of roller screen is gradually reduced with the increase of feed concentration.
In this paper, the discrete element method (DEM) software EDEM is used to simulate the screening process of the roller screen. The simulation experiment focuses on the motion state of each particle in the roller screen at different rotational speeds and the penetration of the screen. In order to reduce the calculation time, the sieve cylinder model and the particle model are simplified. Comparing the calculated classification efficiency with the actual test classification efficiency, the classification law is basically the same, and the classification efficiency increases with the increase of rotational speed. Through the analysis of the motion state of particles in the roller screen, it is concluded that the motion state of different particle sizes in the roller screen is different: the smaller the particle size, the bigger the position angle in the sliding motion state, and the throwing motion. The bigger the throwing angle is, the smaller the position angle and throwing angle are; with the increase of rotational speed, the area of the screen will expand along the rotational direction, and when the rotational speed is 0.91Nc, it will penetrate the screen almost in the whole circumferential direction. Different, the smaller the particle size, the smaller the propelling role of the screw, the larger the particle size, the greater the propelling role of the screw; Through the analysis of different particle sieve, it is found that the higher the rotational speed, the faster the screen penetration, and the smaller the particle size, the easier the screen penetration.
This paper studies the trial-produced drum screen from two different aspects of actual material test and EDEM simulation test, and draws some useful conclusions, which provide a certain basis for guiding the design and optimization of drum screen.
【學位授予單位】：太原理工大學
【學位級別】：碩士
【學位授予年份】：2015
【分類號】：TD94
本文編號：2191797
[Abstract]:Coarse slime is a kind of associated slime in the process of coal washing and dressing. The slime has small particle size, about 1 mm, wide grade, complex particle shape, large surface area, strong water holding capacity, high moisture content, and exists in a large number of coal preparation plants. Whether it can effectively dehydrate and desliming this part of slime and achieve recovery has considerable economic benefits. In recent years, independent separation of coarse slime has become an established process, but due to the influence of particle size in hydraulic separation, the ash content of fine material is always greater than that of coarse material, and the desliming effect of existing fine particle screening equipment is not satisfactory, resulting in high ash content of coarse slime concentrate. Therefore, it is urgent to study a new type of high efficiency coarse slime separation. The stage dewatering and desliming equipment improves the recovery effect of coarse slime.
In this paper, the roller screen is applied to the dewatering and desliming of coarse coal slurry recovery process, and a roller screen suitable for the treatment of coal slurry water is trial-manufactured, and a spiral guide vane is added to the inner wall of the screen cylinder, instead of discharging through the installation of inclination angle. In the middle, the coarse particles settle rapidly to the inner wall of the sieve barrel, and because the rotation of the sieve barrel drives the material layer to tilt upward and roll over, the resistance of the upper suspension layer is significantly reduced, and the solid particles which are not penetrated through the sieve can discharge along the axis of the sieve barrel under the impetus of gravity and spiral diversion. The sieve is sewn down by the seams, and the material layer is derived from the axial direction of the spiral guide vane.
The drum sieve was used to classify the coarse coal slime. The operation parameters (drum speed and feed flow) and the feed properties (concentration and particle size) were studied. The results showed that the drum sieve had a good effect on the dewatering and classification of the coarse coal slime and the water content of the product on the sieve was good. The rotational speed of the roller screen has a significant effect on the dehydration and classification. The higher the rotational speed, the better the dehydration and classification effect. The feed flow rate also determines the rotational speed of the roller screen. The greater the flow rate, the greater the rotational speed required. When the degree of dehydration is 30%, the dehydration effect is the worst, lower or higher than 30% will enhance the dehydration effect; the classification effect of roller screen is gradually reduced with the increase of feed concentration.
In this paper, the discrete element method (DEM) software EDEM is used to simulate the screening process of the roller screen. The simulation experiment focuses on the motion state of each particle in the roller screen at different rotational speeds and the penetration of the screen. In order to reduce the calculation time, the sieve cylinder model and the particle model are simplified. Comparing the calculated classification efficiency with the actual test classification efficiency, the classification law is basically the same, and the classification efficiency increases with the increase of rotational speed. Through the analysis of the motion state of particles in the roller screen, it is concluded that the motion state of different particle sizes in the roller screen is different: the smaller the particle size, the bigger the position angle in the sliding motion state, and the throwing motion. The bigger the throwing angle is, the smaller the position angle and throwing angle are; with the increase of rotational speed, the area of the screen will expand along the rotational direction, and when the rotational speed is 0.91Nc, it will penetrate the screen almost in the whole circumferential direction. Different, the smaller the particle size, the smaller the propelling role of the screw, the larger the particle size, the greater the propelling role of the screw; Through the analysis of different particle sieve, it is found that the higher the rotational speed, the faster the screen penetration, and the smaller the particle size, the easier the screen penetration.
This paper studies the trial-produced drum screen from two different aspects of actual material test and EDEM simulation test, and draws some useful conclusions, which provide a certain basis for guiding the design and optimization of drum screen.
【學位授予單位】：太原理工大學
【學位級別】：碩士
【學位授予年份】：2015
【分類號】：TD94
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