本文選題：多元體系 + 水合物��； 參考：《吉林大學(xué)》2017年碩士論文

【摘要】：由于人類社會(huì)和經(jīng)濟(jì)的發(fā)展長時(shí)間依靠傳統(tǒng)化石能源,目前,全球范圍內(nèi)的氣候變化,資源匱乏和環(huán)境污染等問題日益加劇。天然氣水合物(簡(jiǎn)稱水合物)作為一種清潔高效的非常規(guī)能源正逐漸成為全世界的研究熱點(diǎn)。自然界中的水合物按成因氣類型可分為生物成因的甲烷水合物和熱解成因的多元體系水合物。多元體系水合物因組成復(fù)雜,結(jié)構(gòu)多樣,其分解特性與常規(guī)甲烷水合物有很大差異。此外,在常規(guī)的水合物開采方法中,降壓法被認(rèn)為是最經(jīng)濟(jì)可行的開采方法。因此,有必要開展多元體系水合物降壓分解特性的研究。首先利用透明攪拌釜開展了CH_4-C_2H_6、CH_4-C_3H_8、C_2H_6-C_3H_8和CH_4-C_2H_6-C_3H_8四種組分水合物的形成實(shí)驗(yàn)。實(shí)驗(yàn)中觀察到攪拌下多元體系水合物的形成由溶解氣形成和氣液界面形成兩種機(jī)制共同作用。CH_4-C_2H_6、CH_4-C_3H_8和CH_4-C_2H_6-C_3H_8水合物形成時(shí),氣相中各組分表現(xiàn)出明顯的分離效應(yīng),而C_2H_6-C_3H_8水合物形成時(shí),氣相中各組分相對(duì)含量逐漸靠近。多元體系水合物形成時(shí)按照C_3H_8,C_2H_6和CH_4的順序先后填充到水合物的籠型結(jié)構(gòu)中。其次,分別利用透明攪拌釜和靜態(tài)反應(yīng)釜開展了二元(CH_4-C_2H_6、CH_4-C_3H_8和C_2H_6-C_3H_8)和三元(CH_4-C_2H_6-C_3H_8)水合物的降壓分解實(shí)驗(yàn),分別研究了溫度、壓力和體系類型對(duì)降壓分解特性的影響。多元體系水合物在高壓分解時(shí),因水合物的籠型結(jié)構(gòu)填充的氣體不同而具有不同的穩(wěn)定性,水合物的分解存在多個(gè)階段,C_2H_6和C_3H_8分別存在“短暫滯留”和“長期滯留”的現(xiàn)象,該現(xiàn)象在靜態(tài)體系、低溫、高壓和各組分結(jié)構(gòu)穩(wěn)定性差異較大時(shí)更加明顯。因上述組分滯留現(xiàn)象的存在,使分解區(qū)滯留的水合物形成一層水合物膜包裹在內(nèi)部水合物顆粒的周圍,阻礙內(nèi)部水合物的分解,使體系進(jìn)入“亞穩(wěn)態(tài)”,形成部分分解的現(xiàn)象。最后,研究了多元體系水合物在冰點(diǎn)下的分解特性。實(shí)驗(yàn)結(jié)果表明各類型水合物在冰點(diǎn)下均存在部分分解現(xiàn)象,且在-4℃時(shí)這種現(xiàn)象較-1℃更明顯,該現(xiàn)象源于冰點(diǎn)下水合物自保護(hù)效應(yīng)的冰膜。此外,冰膜不斷增厚,C_3H_8的組分滯留現(xiàn)象逐漸顯現(xiàn)出來,且-4℃較-1℃更早出現(xiàn),而實(shí)驗(yàn)條件下C_2H_6未出現(xiàn)明顯的組分滯留現(xiàn)象。
[Abstract]:Because the development of human society and economy depends on the traditional fossil energy for a long time, the problems of climate change, resource scarcity and environmental pollution in the world are becoming more and more serious. As a kind of clean and efficient unconventional energy, natural gas hydrate (gas hydrate) has gradually become a research hotspot all over the world. The hydrates in nature can be divided into biogenic methane hydrates and pyrolytic multicomponent hydrates according to the type of gas. Because of the complex composition and diverse structure, the decomposition characteristics of the multicomponent hydrate are quite different from those of the conventional methane hydrate. In addition, depressurization is considered to be the most economical and feasible method in conventional hydrate mining. Therefore, it is necessary to study the decomposing characteristics of hydrates. At first, the Ch _ S _ 4-C _ 2H _ 6C _ _ _ It was observed in the experiment that the formation of hydrates in the multicomponent system under agitation combined the formation of dissolved gas and the formation of gas-liquid interface. CH4-C2H2H6-C3H8, and the components in the gas phase showed an obvious separation effect when they were formed, and when the C _ 2H _ 6-C _ 3H _ 8 hydrate was formed, the number of components in the gas phase showed a distinct separation effect when they were formed, and the number of C _ 2H _ 6-C _ 3H _ (8) was compared with that of C _ 2H _ 6-C _ 3H _ 8. The relative content of each component in the gas phase is gradually approaching. When the hydrates were formed in the multicomponent system, the structure of the hydrates was filled into the cage structure of the hydrates successively according to the order of C _ S _ 3H _ 8H _ (8) and C _ s _ 2H _ S _ 6 and Ch _ s _ 4. Secondly, by using a transparent stirred tank and a static reactor, respectively, the depressurization experiments of binary CHS _ 4-C _ 2H _ 2S _ T _ 6CH4-C _ 3H _ S _ 8 and C _ 2H _ 6-C _ 3H _ 3H _ 8 and S _ 2H _ 4-C _ 2C _ 3H _ 8) hydrate were carried out, respectively, and the effects of temperature, pressure and the type of system on the characteristics of the decompression were studied respectively. When the hydrates are decomposed at high pressure, the hydrates have different stability because of the different gas filled with the cage structure of the hydrates. There are many stages of decomposition of hydrates, such as "short stay" and "long stay" in C _ 2H _ 6 and C _ S _ 3H _ 8, respectively, when the hydrates are decomposed at high pressure. This phenomenon is more obvious in static system, low temperature, high pressure and structural stability of each component. Due to the existence of the retention phenomenon of the components mentioned above, the hydrates in the decomposition zone form a layer of hydrate membrane around the inner hydrate particles, which hinders the decomposition of the internal hydrates and makes the system enter into the "metastable state" and form the phenomenon of partial decomposition. Finally, the decomposition characteristics of hydrates at freezing point were studied. The experimental results show that all types of hydrates are partially decomposed at freezing point, and this phenomenon is more obvious at -4 鈩，

本文編號(hào)：1993918