本文選題：稻草 + 烘焙　； 參考：《華東理工大學(xué)》2017年博士論文

【摘要】：生物質(zhì)多富含氯和堿金屬,在熱化學(xué)轉(zhuǎn)化過(guò)程中部分氯和堿金屬將釋放至氣相,導(dǎo)致設(shè)備和運(yùn)行問(wèn)題以及環(huán)境污染問(wèn)題。本文以稻草、木屑、馬尾藻和玉米稈為生物質(zhì)原料,研究了生物質(zhì)烘焙過(guò)程中氯和鉀的遷移行為。同時(shí)本文結(jié)合烘焙稻草高溫?zé)峤饨沟奈锢砘瘜W(xué)性質(zhì),進(jìn)一步研究了烘焙預(yù)處理對(duì)稻草高溫?zé)峤膺^(guò)程中氯和鉀遷移行為的影響。主要研究結(jié)論如下:(1)研究了生物質(zhì)烘焙過(guò)程中氯和鉀的釋放及賦存形態(tài)轉(zhuǎn)化規(guī)律,并考察了烘焙生物質(zhì)的化學(xué)組成、表面形貌和孔隙結(jié)構(gòu)。結(jié)果表明,當(dāng)烘焙溫度低于250—時(shí),烘焙對(duì)生物質(zhì)孔隙結(jié)構(gòu)的影響較小;當(dāng)烘焙溫度為300—時(shí),中孔和大孔的比表面積略有增大,微孔比表面積則顯著增加。氯的釋放與脫揮發(fā)分同步,并且無(wú)機(jī)氯部分轉(zhuǎn)化為有機(jī)氯賦存在烘焙生物質(zhì)中。鉀的釋放率小于氯的釋放率,水溶態(tài)鉀部分轉(zhuǎn)化為離子交換態(tài)鉀,同時(shí)顆粒粒徑對(duì)鉀的遷移影響較小。烘焙稻草表面還存.在富含氯和鉀元素的顆粒物。(2)研究了烘焙預(yù)處理對(duì)稻草800-1200℃高溫?zé)峤饨贡砻嫘蚊�、孔隙結(jié)構(gòu)和石墨化程度的影響,考察了烘焙稻草高溫?zé)峤饨沟臍饣磻?yīng)活性。結(jié)果表明,烘焙預(yù)處理導(dǎo)致稻草高溫?zé)峤饨沟谋缺砻娣e減小。稻草烘焙過(guò)程中揮發(fā)分脫除越多,則高溫?zé)峤饨沟谋缺砻娣e越小。300℃烘焙預(yù)處理導(dǎo)致水洗稻草高溫?zé)峤饨沟谋缺砻娣e顯著增大。當(dāng)烘焙溫度高于250℃時(shí),烘焙導(dǎo)致稻草熱解焦的石墨化程度降低。隨著烘焙溫度的升高,水洗稻草熱解焦的石墨化程度則升高。烘焙均導(dǎo)致稻草和水洗稻草熱解焦的氣化反應(yīng)活性降低。(3)研究了稻草原料及烘焙稻草在800-1200℃熱解過(guò)程中氯和鉀的釋放及賦存形態(tài)轉(zhuǎn)化規(guī)律,分析了烘焙預(yù)處理對(duì)稻草高溫?zé)峤膺^(guò)程中氯和鉀遷移規(guī)律的影響。結(jié)果表明,隨著烘焙溫度的升高,熱解過(guò)程中氯的釋放率存在減小趨勢(shì)。當(dāng)熱解溫度低于900℃時(shí),烘焙導(dǎo)致稻草烘焙和熱解整個(gè)過(guò)程中鉀的總釋放率大于稻草原料的鉀釋放率;當(dāng)熱解溫度高于1000℃時(shí),烘焙稻草的鉀總釋放率與稻草原料的鉀釋放率相近。烘焙對(duì)稻草高溫?zé)峤膺^(guò)程中氯和鉀遷移行為的影響主要包括五個(gè)方面:①烘焙過(guò)程中形成有機(jī)氯;②烘焙過(guò)程中水溶態(tài)鉀轉(zhuǎn)化為離子交換態(tài)鉀;③烘焙過(guò)程中稻草的揮發(fā)分含量降低;④烘焙減弱了高溫?zé)峤饨沟亩嗫滋匦?⑤烘焙過(guò)程中氯和鉀在稻草表面富集。
[Abstract]:Biomass is rich in chlorine and alkali metals, some of which will be released to gas phase in the process of thermochemical conversion, resulting in equipment and operation problems and environmental pollution. The migration behavior of chlorine and potassium during biomass baking was studied using straw, sawdust, sargassum and cornstalk as biomass raw materials. At the same time, combined with the physical and chemical properties of high temperature pyrolysis of baked straw, the effects of baking pretreatment on the migration of chlorine and potassium during the high temperature pyrolysis of straw were further studied. The main conclusions are as follows: (1) the release and transformation of chlorine and potassium during biomass baking were studied, and the chemical composition, surface morphology and pore structure of roasted biomass were investigated. The results showed that when the baking temperature was lower than 250 -, the effect of baking on the pore structure of biomass was small, and when the baking temperature was 300 -, the specific surface area of mesoporous and macroporous increased slightly, while the specific surface area of micropore increased significantly. The release of chlorine is synchronized with the devolatilization, and the inorganic chlorine is partly converted into organic chlorine, which is stored in roasted biomass. The release rate of potassium is smaller than that of chlorine. The water-soluble potassium is partially transformed into ion-exchange potassium, and the particle size has little effect on the migration of potassium. The baking straw remains on the surface. The effects of baking pretreatment on the surface morphology, pore structure and graphitization degree of rice straw pyrolyzed at 800-1200 鈩，

本文編號(hào)：1775882