發(fā)布時間：2018-05-11 16:08

  本文選題：硅顆粒 + 尾氣系統(tǒng)��； 參考：《中國礦業(yè)大學(xué)》2015年碩士論文

【摘要】：多晶硅生產(chǎn)是光伏能源和微電子工業(yè)的基礎(chǔ)產(chǎn)業(yè),占據(jù)化學(xué)工業(yè)重要位置,主流多晶硅生產(chǎn)技術(shù)—改良西門子法是涉及有毒、易燃、易爆介質(zhì)的化工聯(lián)產(chǎn)過程,生產(chǎn)安全性倍受行業(yè)關(guān)注。實際多晶硅生產(chǎn)中還原尾氣攜帶大量硬質(zhì)硅顆粒排出還原爐,造成尾氣系統(tǒng)過流部件持續(xù)沖蝕,成為多晶硅生產(chǎn)的重大安全隱患。然而,還原尾氣系統(tǒng)管路冗長,結(jié)構(gòu)復(fù)雜,生產(chǎn)現(xiàn)場又缺乏尾氣系統(tǒng)過流部件磨損認(rèn)識,因此尾氣系統(tǒng)抗磨防護(hù)工作的開展困難重重。本文基于氣固兩相流動理論和沖蝕理論,從化工安全角度出發(fā),利用數(shù)值模擬方法,對過流部件的磨損狀況進(jìn)行預(yù)測,并探究工況對局部磨損的影響規(guī)律。在此基礎(chǔ)之上,結(jié)合還原爐尾氣系統(tǒng)生產(chǎn)特點(diǎn),從主動防護(hù)與被動防護(hù)的角度,對系統(tǒng)過流部件進(jìn)行磨損治理,指導(dǎo)生產(chǎn)實踐,消除多晶硅還原爐尾氣系統(tǒng)中的磨損安全隱患。硅顆粒和尾氣理化性質(zhì)分析表明:硅顆粒成分幾乎全部為無定型硅,微量參雜晶體硅;為硅氣相外延體反應(yīng)、Si HCl3和Si H2Cl2熱解反應(yīng)、溫度波動以及生產(chǎn)系統(tǒng)運(yùn)行不穩(wěn)定等客觀原因?qū)е庐a(chǎn)生。研究以尾氣出口管道為對象,確定了8個與支管對應(yīng)的環(huán)管底部區(qū)域,2個位于環(huán)管出口兩側(cè)上方位外側(cè)22.5°區(qū)域,4個位于單爐主管上下方位壁面區(qū)為嚴(yán)重磨損區(qū)域;發(fā)現(xiàn)前8個局部磨損區(qū)域為硅顆粒高沖角碰撞所致,后6個區(qū)域為低沖角、高速磨蝕引起,單爐主管上方位壁面磨損最為嚴(yán)重。探究工況影響規(guī)律發(fā)現(xiàn):尾氣速度增加,局部磨損率最大值以指數(shù)規(guī)律增長;硅顆粒直徑增加,磨損區(qū)域變化并出現(xiàn)“粒度效應(yīng)”,局部磨損率最大值增加幅度越來越小。硅顆粒濃度增加,局部磨損率最大值增加幅度越來越大,但兩個局部出現(xiàn)“屏蔽效應(yīng)”,增加幅度越來越小。以尾氣匯流管道為對象深入,確定了匯流管道磨損由低沖角磨蝕造成,局部磨損區(qū)域位于有支管接入的三通下游壁面,其中下方位壁面磨損比上方位嚴(yán)重,外側(cè)壁面磨損比內(nèi)側(cè)壁面嚴(yán)重;支管和上游壁面幾乎不發(fā)生磨損。探究工況影響規(guī)律發(fā)現(xiàn):尾氣速度增加,磨損局部向兩側(cè)移動,局部磨損率最大值以指數(shù)規(guī)律增長;硅顆粒直徑增加,磨損區(qū)域跨方位變化,整個三通單元磨損率最大值線性增長;硅顆粒濃度增加,局部磨損率最大值近乎線性規(guī)律發(fā)展。主、支管流量比例增加,磨損局部由支管正對壁面向下游發(fā)展,整個三通單元磨損率最大值增加幅度越來越大。此外,提出減少硅顆粒產(chǎn)生的生產(chǎn)過程優(yōu)化,采取爐內(nèi)大顆粒尾氣工裝攔截與爐外小顆粒金屬過濾除塵的硅顆粒凈化,以及單爐主管的氣動肋條抗磨措施進(jìn)行主動防護(hù);選擇以高錳鋼焊條堆焊的涂層抗磨,與匯管局部外加耐磨襯塊的厚度補(bǔ)償方式進(jìn)行被動防護(hù)。同時,制定局部磨損區(qū)域厚度監(jiān)測方案。
[Abstract]:Polysilicon production is the basic industry of photovoltaic energy and microelectronics industry. It occupies an important position in the chemical industry. The mainstream polysilicon production technology, the modified SIEMENS method, is a chemical co production process involving toxic, flammable and explosive medium. The production safety is paid much attention by the industry. In actual polycrystalline silicon production, the reduction tail gas is carried a large amount of hard silicon particles The discharge reduction furnace, which causes the continuous erosion of the overcurrent components of the exhaust system, has become a major safety hazard in the production of polysilicon. However, the pipeline of the reduction tail gas system is long and complex, and the production site lacks the understanding of the wear and tear of the overflow components in the exhaust system. Therefore, the anti-wear protection work of the tail gas system is difficult to carry out. This paper is based on the gas-solid two-phase flow. The theory and erosion theory, from the point of view of chemical safety, use the numerical simulation method to predict the wear condition of the overcurrent components and explore the effect of the working condition on the local wear. On this basis, the wear and tear of the system overcurrent components are treated from the angle of active protection and passive protection by combining the production characteristics of the exhaust system of the reduction furnace. In order to guide the production practice and eliminate the risk of wear safety in the exhaust system of the polysilicon reduction furnace, the analysis of the physical and chemical properties of silicon particles and tail gas shows that the silicon particles are almost all amorphous silicon, micro mixed crystal silicon, the reaction of silicon gas phase epitaxy, the reaction of Si HCl3 and Si H2Cl2, the temperature fluctuation and the unstable operation of the production system, etc. The objective causes result. The study takes the tail gas outlet pipeline as the object, and determines the bottom area of 8 ring tube corresponding to the branch pipe, 2 locates in the azimuth 22.5 degree area on the two sides of the ring tube outlet, and the 4 are located in the upper and lower azimuth wall area of the single furnace, and the first 8 local wear regions are caused by the high impact angle collision of silicon particles. The latter 6 regions are low impact angle and high speed abrasion, the most serious wear of the single furnace head is on the azimuth surface. It is found that the rate of tail gas increases, the maximum value of the local wear rate increases exponentially, the diameter of the silicon particles increases, the wear area changes and the "grain effect" appears, and the maximum increase of the local wear rate is increasing. The smaller the concentration of silicon particles increases, the maximum increase of the maximum local wear rate is increasing, but the two local "shielding effect" is more and more small. Taking the tail gas flow pipe as the object, it is determined that the wear of the pipeline is caused by the low impact angle abrasion, and the local wear area is located in the downstream wall of the three pass with a branch pipe. The wear of the lower azimuth surface is worse than that of the upper wall, and the wear of the outer wall is more serious than that of the inner wall, and there is almost no wear on the branch pipe and the upper wall. The maximum wear rate of the whole three pass element increases linearly, the concentration of silicon particles increases and the maximum of the local wear rate is almost linear. The proportion of the flow rate increases, the wear part is developed from the straight wall of the branch pipe to the downstream, and the maximum increase of the wear rate of the whole three passage element is increasing. Furthermore, it is proposed to reduce the production of silicon particles. The production process is optimized, which adopts the silicon particle purification of the large particle tail gas tooling in the furnace and the small particle metal filtration and dust removal outside the furnace, as well as the anti wear measures of the pneumatic ribs in the single furnace, selecting the coating anti wear with the high manganese steel welding electrode and the passive protection with the thickness compensation mode of the local external wear lining block. Set up a regional thickness monitoring scheme for local wear.

【學(xué)位授予單位】：中國礦業(yè)大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：X76;TQ127.2

【引證文獻(xiàn)】

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本文編號：1874641