【摘要】：傳統(tǒng)的電熱法生產(chǎn)電石技術(shù)存在“高污染、高排放、高能耗”等缺點(diǎn),故北京化工大學(xué)劉振宇等提出了一種氧熱法電石生產(chǎn)工藝,同時(shí)也提出了不同的反應(yīng)器設(shè)計(jì)模型。本文針對(duì)年產(chǎn)1萬(wàn)噸電石的中試規(guī)模的復(fù)合床反應(yīng)器開(kāi)展了模型化設(shè)計(jì)研究,也即,采用散體力學(xué)方法驗(yàn)證并考察了兩種攪拌式的復(fù)合床反應(yīng)器固體布料器的流動(dòng)性能,并采用計(jì)算流體力學(xué)(CFD)模擬考察了反應(yīng)器密相區(qū)顆粒的熱解和傳熱特性；同時(shí)針對(duì)反應(yīng)器稀相燃燒區(qū)的設(shè)計(jì),運(yùn)用數(shù)值模擬方法考察了不同燃燒噴嘴設(shè)置下燃燒區(qū)的流動(dòng)特性,據(jù)此提出噴嘴設(shè)置的優(yōu)化設(shè)計(jì)方案。首先,利用離散元法研究了復(fù)合床反應(yīng)器內(nèi)兩種不同槳葉(平槳葉和下壓式槳葉)下器內(nèi)顆粒流動(dòng)以及布料情況。具體結(jié)論如下：(1)在兩種攪拌槳葉下顆粒在床層中的速度分布基本一致,靠近攪拌槳葉的下部床層顆粒速度相對(duì)較大；上部床層由于顆粒遠(yuǎn)離槳葉,表現(xiàn)出明顯的架橋現(xiàn)象,床層中顆粒速度分布不均勻；(2)平槳葉下顆粒在反應(yīng)器徑向上呈現(xiàn)“中間多,兩邊少”的布料分布,而下壓式槳葉呈現(xiàn)“中間少、兩邊多”的布料分布;(3)在相同的轉(zhuǎn)速下,采用平槳葉時(shí)顆粒在反應(yīng)器徑向上的分布波動(dòng)比較大,而下壓式槳葉布料相對(duì)均勻,從相對(duì)理想的布料形式來(lái)說(shuō),下壓式槳葉是更可采取的。其次,以復(fù)合移動(dòng)床反應(yīng)器的移動(dòng)床段為研究對(duì)象,以40mm復(fù)合顆粒為電石原料,研究了移動(dòng)床段從冷態(tài)開(kāi)車到熱態(tài)運(yùn)行所需時(shí)間及反應(yīng)器熱態(tài)運(yùn)行時(shí)器內(nèi)組分、溫度等分布情況。結(jié)論如下：(1)通過(guò)模擬得到移動(dòng)床從冷態(tài)運(yùn)行至熱態(tài)正常運(yùn)行時(shí),所需時(shí)間為1200s,即開(kāi)車時(shí)間至少為1200s;(2)隨著時(shí)間增加,反應(yīng)器內(nèi)流場(chǎng)、溫度場(chǎng)、組分分布明顯不同。熱解初期,反應(yīng)器內(nèi)三場(chǎng)分布相對(duì)均勻；隨著熱解時(shí)間增加,壁面效應(yīng)增強(qiáng),反應(yīng)器內(nèi)三場(chǎng)分布均呈現(xiàn)W型分布;(3)隨著床層中熱解前沿的上移,反應(yīng)器內(nèi)可以明顯的劃分為熱解完成區(qū)、熱解區(qū)、未反應(yīng)區(qū)的三段分布狀態(tài)；(4)隨著溫度升高,復(fù)合顆粒內(nèi)先后發(fā)生水分蒸發(fā)、煤熱解、氫氧化鈣熱解,但是各物質(zhì)在釋放過(guò)程并沒(méi)有表現(xiàn)出明顯的界限。最后,對(duì)復(fù)合移動(dòng)床反應(yīng)器冷態(tài)下的流動(dòng)建立數(shù)學(xué)模型,研究不同氧氣噴嘴入口位置、入口角度、進(jìn)氣速度對(duì)反應(yīng)器內(nèi)流動(dòng)、旋流的影響,選出了適宜的噴嘴設(shè)計(jì)參數(shù)：氧噴嘴入口位于距熔池表面的高度為0.43m、入射角度為150、進(jìn)氣速度為80m/s。
[Abstract]:The traditional technology of producing calcium carbide by electrothermal method has the disadvantages of "high pollution, high emission and high energy consumption". Therefore, Liu Zhenyu, Beijing University of Chemical Technology, has put forward an oxythermal calcium carbide production process and different reactor design models. In this paper, the model design of a pilot-scale composite bed reactor with an annual production of 10,000 tons of calcium carbide has been studied. In other words, the fluidity of solid distributor in two kinds of stirred bed reactors has been verified and investigated by means of bulk mechanics method. The pyrolysis and heat transfer characteristics of the dense phase particles in the reactor were investigated by computational fluid dynamics (CFD) simulation, and the flow characteristics of the combustion zone with different combustion nozzles were investigated by numerical simulation for the design of the lean phase combustion zone of the reactor. According to this, the optimal design scheme of nozzle setting is put forward. Firstly, the particle flow and distribution in two different blades (flat blade and lower pressure blade) in a composite bed reactor were studied by discrete element method. The specific conclusions are as follows: (1) the velocity distribution of particles in the bed is basically the same under the two kinds of agitating blades, the velocity of the lower bed near the agitating blade is relatively large, and the upper bed is obviously bridging because the particles are far away from the blade. The velocity distribution of particles in the bed is not uniform; (2) the distribution of particles under the flat blade is "more in the center, less in both sides" in the radial direction of the reactor, while the distribution of "less in the middle and more on both sides" in the bottom pressure blade; (3) at the same speed, The distribution of the particles in the radial direction of the reactor is more fluctuant when the flat blade is used, but the distribution of the lower pressure blade is relatively uniform, so the lower pressure blade is more suitable for the relatively ideal distribution form. Secondly, taking the moving bed section of the complex moving bed reactor as the research object and the 40mm composite particle as the raw material of calcium carbide, the time required for the moving bed section to start up from cold to hot state and the components in the reactor during the hot state operation were studied. Temperature distribution The results are as follows: (1) when the moving bed is running from cold to hot, the time required is 1200 s, that is, the start-up time is at least 1 200 s; (2) with the increase of time, the flow field, temperature field and component distribution in the reactor are obviously different. In the initial stage of pyrolysis, the distribution of the three fields in the reactor is relatively uniform; with the increase of the pyrolysis time, the wall effect increases, and the distribution of the three fields in the reactor is W-shaped; (3) with the moving up of the pyrolysis front in the bed, The reactor can be divided into three stages of pyrolysis, pyrolysis and non-reaction. (4) with the increase of temperature, water evaporation, coal pyrolysis and calcium hydroxide pyrolysis occur successively in the composite particles. However, the release of the substances did not show a clear boundary. Finally, the mathematical model of the flow in the cold state of the complex moving bed reactor is established, and the effects of the inlet position, inlet angle and inlet velocity of the oxygen nozzle on the flow and swirl in the reactor are studied. The optimum design parameters of the nozzle are as follows: the inlet height of the oxygen nozzle is 0.43m from the surface of the molten pool, the angle of incidence is 150, and the inlet velocity is 80m / s.
【學(xué)位授予單位】：北京化工大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類號(hào)】：TQ161;TQ052

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本文編號(hào)：2120555