本文選題：褐煤 + VTI可磨性指數(shù)�。� 參考：《中國礦業(yè)大學(xué)》2015年碩士論文

【摘要】：我國煤炭大部分被用于直接燃燒,其中發(fā)電用煤占有量最大,增長也最快,近幾年被認(rèn)為是劣質(zhì)煤種的褐煤越來越受到重視,越來越多的火力發(fā)電廠已經(jīng)燃用或準(zhǔn)備燃用褐煤。目前我國90%以上的燃煤電廠采用煤粉燃燒方式,磨煤是制粉系統(tǒng)的必備環(huán)節(jié),磨煤能耗和磨后產(chǎn)品的粒度分布是整個(gè)制粉系統(tǒng)中最為關(guān)注的問題,電廠希望以最低的磨煤能耗獲得最佳的煤粉細(xì)度。因此研究褐煤的可磨性指數(shù)變化情況及其磨碎過程,對(duì)于降低磨礦能耗、提高破碎效率和控制煤粉的粒度分布有著重要的意義。論文首先對(duì)來自內(nèi)蒙古地區(qū)的褐煤的礦物學(xué)特性做了詳細(xì)的研究。煤樣的灰分為23.69%,屬于中等灰分的煤,發(fā)熱量Qnet.ar為20.05MJ·kg-1,屬于中等發(fā)熱量的煤,煤樣的礦物質(zhì)主要為石英(Si O2)、黃鐵礦(Fe S2)和高嶺石(Al2Si2O5(OH)4),礦物質(zhì)的嵌布以分散狀分布為主,煤和礦物質(zhì)緊密連生,礦物質(zhì)嵌布粒度細(xì)。論文研究了褐煤的密度和粒度對(duì)褐煤VTI可磨性指數(shù)的影響。結(jié)果表明,同一粒度級(jí)下褐煤的VTI可磨性指數(shù)隨著密度增大而增大;同一密度級(jí)下褐煤的VTI可磨性指數(shù)隨著初始粒度的增大有增大的趨勢。研究中,運(yùn)用實(shí)驗(yàn)室中速磨模型機(jī)對(duì)褐煤的破碎過程進(jìn)行了探究。褐煤在中速磨模型機(jī)中的研磨屬于一級(jí)破碎動(dòng)力學(xué)過程,煤樣的破碎速率隨著初始粒級(jí)的增大而增大;隨著初始粒度的增大,-0.09mm粒級(jí)的生成速率隨研磨時(shí)間的延伸由逐漸減小向先增大而后減小的趨勢變化;磨機(jī)功率隨著研磨的進(jìn)行逐漸減小,最終達(dá)到相對(duì)穩(wěn)定的狀態(tài);隨著研磨時(shí)間的增加和初始粒級(jí)的減小,磨礦產(chǎn)品的細(xì)度逐漸減小,在各個(gè)研磨時(shí)間段的粒度呈近似正態(tài)分布;羅遜—拉姆勒粒度特性方程能較好的反映中速磨模型機(jī)磨礦產(chǎn)物的粒度特性,給料粒度為11.2~8.0mm、磨礦時(shí)間為1min的磨礦產(chǎn)物的羅遜—拉姆勒粒度特性方程為: = 100-0.58321.183論文初步分析了添加助磨劑炭黑對(duì)褐煤破碎特性的影響。-0.09mm粒級(jí)產(chǎn)率的增大量隨著炭黑用量的增大,先快速增大后緩慢減小,在炭黑用量為煤樣質(zhì)量的1%左右時(shí)達(dá)到最大值;添加助磨劑后,各個(gè)密度級(jí)煤樣的VTI可磨性指數(shù)均有所增大,并且其增大量隨密度的增大而增大;另外,褐煤在中速磨模型機(jī)研磨過程中-0.09mm粒級(jí)生成速率與未添加助磨劑時(shí)具有相同的變化規(guī)律,但數(shù)值均有所增大;助磨劑的效果會(huì)隨著研磨時(shí)間的增大而變好;在磨機(jī)功耗大致相同的情況下,添加炭黑作為助磨劑可以降低磨礦產(chǎn)品的細(xì)度,從而起到降低磨礦功耗的作用。
[Abstract]:Most of the coal in our country is used for direct combustion, among which the coal for power generation is the largest and the growth is fastest. In recent years, lignite, which is regarded as inferior coal, has been paid more and more attention, and more thermal power plants have burned or prepared to burn lignite. At present, more than 90% of coal-fired power plants in China adopt pulverized coal combustion mode. Grinding coal is an essential part of pulverizing system. The energy consumption of grinding coal and the particle size distribution of products after grinding are the most concerned problems in the whole pulverized coal making system. The power plant hopes to obtain the best pulverized coal fineness with the lowest energy consumption. Therefore, it is of great significance to study the change of grindability index and grinding process of lignite for reducing grinding energy consumption, improving crushing efficiency and controlling particle size distribution of pulverized coal. Firstly, the mineralogical characteristics of lignite from Inner Mongolia are studied in detail. The ash of coal samples is divided into two parts: coal of medium ash, calorific Qnet.ar of 20.05MJ kg-1 and coal of medium calorific value. The minerals of coal samples are mainly quartz siloxane, pyrite and pyrite, and kaolinite Al2Si2O5OH4, and the distribution of minerals is mainly dispersed. Coal and minerals are closely linked, mineral distribution fine grain size. The influence of density and particle size of lignite on VTI grindability index of lignite was studied in this paper. The results show that the VTI grindability index of lignite increases with the increase of density, and the VTI grindability index of lignite increases with the increase of initial particle size. In the study, the crushing process of lignite was studied by using the model machine of medium-speed mill in laboratory. The grinding of lignite in medium speed mill belongs to the first order crushing dynamic process, and the crushing rate of coal sample increases with the increase of initial particle size. With the increase of the initial particle size, the rate of particle size formation changes from decreasing gradually to increasing first and then decreasing with the extension of grinding time, and the mill power decreases gradually with the grinding, and finally reaches a relatively stable state. With the increase of grinding time and the decrease of initial particle size, the fineness of grinding products decreases gradually, and the granularity of grinding products is approximately normal distribution in each grinding period. Rosson-Ramler particle size characteristic equation can well reflect the particle size characteristics of grinding products of medium speed grinding model machine. The particle size of the grinding product with grinding time of 1min is: = 100-0.58321.183. The effect of the addition of grinding aid carbon black on the crushing characteristics of lignite is analyzed preliminarily. The increase of particle yield of .-0.09mm is with the increase of the amount of carbon black, and the grain size is 11.2mm and 8.0mm respectively, and the grinding time is 1min, and the particle size characteristic equation of grinding product is: = 100-0.58321.183. The content of carbon black was about 1% of the coal sample mass, and the VTI grindability index of each density grade coal sample increased after adding grinding aids, and the increase increased with the increase of coal density, the content of carbon black reached the maximum when the content of carbon black was about 1% of the coal sample mass, and the grindability index of each density grade coal sample increased with the addition of grinding aids. In addition, the formation rate of -0.09mm grain size of lignite in the grinding process of medium speed mill model machine has the same change law as that without adding grinding aid, but the value of lignite increases, and the effect of grinding aid will be improved with the increase of grinding time. When the mill power consumption is about the same, adding carbon black as grinding aid can reduce the fineness of grinding products and thus play the role of reducing grinding power consumption.
【學(xué)位授予單位】：中國礦業(yè)大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類號(hào)】：TD849.2

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