本文選題：生物質(zhì)焦油 + 復(fù)合球團��； 參考：《青島理工大學(xué)》2015年碩士論文

【摘要】：鉻渣污染是當今對環(huán)境威脅最大的難題之一,我國現(xiàn)存鉻渣超過6×106t并逐年累加,由于堆存方式缺乏管理、處理技術(shù)落后等原因,鉻渣析出的Cr(VI)對人類居住地、水源、大氣形成了巨大的安全隱患。針對目前鉻渣無害化處理技術(shù)的優(yōu)缺點,結(jié)合生物質(zhì)資源儲量豐富、易獲取和可再生的特點,本研究提出生物質(zhì)氣化副產(chǎn)品—生物質(zhì)焦油用于鉻渣解毒的新途徑,將二者混合制成復(fù)合球團進行熱解還原實驗,促進Cr(VI)向Cr(III)的形態(tài)轉(zhuǎn)化,實現(xiàn)“以廢治廢”,并對該焦油熱解解毒機理與參數(shù)優(yōu)化匹配展開研究,為后續(xù)生物質(zhì)焦油在鉻渣無害化處理領(lǐng)域使的應(yīng)用提供理論依據(jù)和技術(shù)支持。首先考察了熱解時間,溫度,鉻渣與焦油當量比,球團粒徑,鉻渣粒徑等若干因素對鉻渣中Cr(VI)還原度的影響;然后通過正交實驗得出鉻渣還原的最佳工況;最后結(jié)合實驗數(shù)據(jù),對還原過程進行了熱力學(xué)與動力學(xué)機理研究,得出結(jié)論如下:1.球團粒徑對Cr(VI)還原度的影響最為顯著,結(jié)果表明:直徑2.5mm的球團有利于提高還原鉻產(chǎn)品的質(zhì)量,Cr(VI)還原度最高為93.12%;還原度隨熱解溫度增加先提高后降低,溫度400℃下鉻渣還原度最高;還原度隨熱解時間的增加先提升后緩慢下降,考慮能耗成本,還原時間以10min為宜;增加生物質(zhì)焦油的用量能夠提高Cr(VI)還原度,但焦油過量會導(dǎo)致球團質(zhì)量和還原度的下降,球團中鉻渣與焦油當量比最佳值為2.29:1;鉻渣粒徑越小對還原反應(yīng)越有利。通過正交實驗得出,焦油熱解還原鉻渣的最佳工況為:球團烘干時間40min,熱解溫度400℃,熱解時間10min,鉻渣與焦油當量比2.29:1,鉻渣粒徑為0.074mm,球團粒徑為2.5mm。2.生物質(zhì)焦油還原鉻渣的反應(yīng)屬于一級反應(yīng),反應(yīng)的活化能為17298.94J·mol-1。在反應(yīng)溫度573.15K-773.15K范圍內(nèi),生物質(zhì)焦油還原鉻渣的過程中吉布斯自由焓為極大的負值,反應(yīng)容易發(fā)生;反應(yīng)平衡常數(shù)最大為8.93×10101,表明該反應(yīng)能夠進行的很徹底;鉻渣還原以焦油裂解產(chǎn)生的C還原Cr(VI)的固-固反應(yīng)形式為主。
[Abstract]:The pollution of chromium slag is one of the most dangerous problems to the environment today. The existing chromium slag in our country is more than 6 脳 106 tons and accumulated year by year. Due to the lack of management of storage mode and backward treatment technology, chromium slag precipitated from chromium slag has great influence on human habitation and water resources. The atmosphere poses a huge security hazard. In view of the advantages and disadvantages of the current harmless treatment technology of chromium slag and the characteristics of rich, easy to obtain and renewable biomass resources, a new way of detoxification of chromium residue by biomass gasification by-product, biomass tar, was put forward in this study. The pyrolysis and reduction experiments of the composite pellets were carried out to promote the morphological transformation of CrVI to CrHIII, and to realize "treating waste with waste". The mechanism of pyrolysis and detoxification of the tar was studied, and the optimum matching of parameters was also studied. It provides theoretical basis and technical support for the application of biomass tar in the field of harmless treatment of chromium slag. The effects of several factors, such as pyrolysis time, temperature, the ratio of chromium slag to coke oil equivalent, pellet diameter and chromium slag particle size, on the reduction degree of Cr-VI in chromium slag were investigated, and the optimum condition of chromium slag reduction was obtained by orthogonal experiment. The thermodynamic and kinetic mechanism of the reduction process has been studied. The conclusion is as follows: 1. The effect of pellet diameter on the reduction degree of CrVI was most significant. The results showed that the pellets with diameter 2.5mm were beneficial to the improvement of the quality of Cr products and the reduction degree was 93.12%, and the reduction degree increased first and then decreased with the increase of pyrolysis temperature. The reduction degree of chromium slag was the highest at 400 鈩，

本文編號：1960938