氣升式反應(yīng)器中生物脫硫特性研究

生物工程論文編號(hào):SW175  論文字?jǐn)?shù):12717,頁數(shù):26

II
 目  錄 
中文摘要 I
英文摘要 II
目錄 III
1. 緒論 1
 1.1 燃料油中的硫及其危害 1
 1.2 燃料油脫硫技術(shù) 2
    1.2.1 催化加氫脫硫 3
 1.2.2 生物脫硫 3
 1.3 生化反應(yīng)設(shè)計(jì) 4
    1.3.1 攪拌式反應(yīng)器 4
    1.3.2 氣升式反應(yīng)器 5
 1.4 生物脫硫存在的問題 6
 1.5 本論文的研究?jī)?nèi)容 7
2. 實(shí)驗(yàn)部分 8
 2.1 實(shí)驗(yàn)材料   8
 2.1.1 儀器與試劑  8
 2.1.2 培養(yǎng)基  8
 2.1.3 實(shí)驗(yàn)用生物菌種制備  9
 2.1.4 菌種衰退防止和保藏  9
 2.1.5 氣式反應(yīng)器實(shí)驗(yàn)裝置  10
 2.2 實(shí)驗(yàn)方法 11
     2.2.1 細(xì)胞濃度測(cè)定  11
     2.2.2 有機(jī)雜環(huán)化合物及其產(chǎn)物測(cè)定  11
 2.3 微生物脫硫性能研究 13
     2.3.1 搖瓶中休止細(xì)胞脫硫活力測(cè)定  13
     2.3.2 反應(yīng)器中休止細(xì)胞脫硫活力測(cè)定  13

III
3. 結(jié)果與討論 14
 3.1 實(shí)驗(yàn)結(jié)果與討論 14
   3.1.1 生長(zhǎng)細(xì)胞的生長(zhǎng)特性比較  14
   3.1.2 休止細(xì)胞的脫硫特性比較  15
 3.2 反應(yīng)器生物脫硫過程中工藝因素考察 16
 3.2.1 表觀氣速對(duì)休止細(xì)胞脫硫的影響 16
 3.2.2 水相介質(zhì)的影響 18
 3.2.3 休止細(xì)胞濃度的影響 19
 3.2.4 DBT初始濃度的影響 20
4．總結(jié)與展望 22
 4.1 實(shí)驗(yàn)總結(jié) 22
 4.2 實(shí)驗(yàn)展望 22
致謝 23
參考文獻(xiàn) 24

 摘要：本文通過采用實(shí)驗(yàn)室自主分離的脫硫菌株分支桿菌ZD-19，對(duì)促進(jìn)生物脫硫的工業(yè)應(yīng)用進(jìn)行研究。考察了ZD-19對(duì)4甲基二苯并噻吩(4MDBT)的脫硫特性，實(shí)驗(yàn)結(jié)果表明ZD-19也能專一性的切斷4MDBT的C-S鍵，且由于4MDBT獨(dú)特的不對(duì)稱結(jié)構(gòu)，代謝過程中羥基取代位置發(fā)生變化，所得產(chǎn)物為兩個(gè)同分異構(gòu)體：4甲基2苯基苯酚和2羥基3甲基聯(lián)苯。研究還證實(shí)ZD-19并不能有效降解苯并噻吩(BT)。本部分實(shí)驗(yàn)表明ZD-19是一株對(duì)DBT及其衍生物有較高去除效率的優(yōu)勢(shì)菌種。
 目前BDS研究還局限于搖瓶實(shí)驗(yàn)，生物脫硫反應(yīng)器的設(shè)計(jì)與研究具有重要意義。本研究在自行設(shè)計(jì)的氣升式反應(yīng)器中生物降解正十六烷中的DBT，對(duì)氣升式反應(yīng)器的基本工藝參數(shù)進(jìn)行優(yōu)化。在實(shí)驗(yàn)所選的條件下，最佳表觀速率為11.8cm/s。表觀速率達(dá)到13.0cm/s時(shí)，出現(xiàn)輕微柱塞流現(xiàn)象，液滴直徑增大，傳質(zhì)效果開始降低。反應(yīng)器中ZD-19休止細(xì)胞在生長(zhǎng)介質(zhì)（培養(yǎng)基）和非生長(zhǎng)介質(zhì)（磷酸緩沖溶液）中具有幾乎相同的脫硫活性；過低的菌液濃度下不僅兩相界面小，傳質(zhì)速率低，也使DBT對(duì)細(xì)胞的毒性作用明顯，脫硫效率很差，實(shí)驗(yàn)條件下10-40g/L的菌液濃度都具有較好的比脫硫速率；增加DBT初始濃度，脫硫量略有增加，直至高DBT的致毒作用使菌液脫硫活性降低，此時(shí)傳質(zhì)速率較高，體系屬于反應(yīng)控制。
 
關(guān)鍵詞：生物脫硫，氣升式反應(yīng)器，模擬燃料油，分支桿菌，二苯并噻吩及其烷基取代物

Abstract: Mycobacterium sp. ZD-19 can metabolize dibenzothiophene(DBT) and 4,6dimethyldibenzothiophene(4,6DMDBT) through a sulfur-specific pathway. The biodesulfurization of 4methyldibezothiophene(4MDBT) by ZD-19 was also investigated in this thesis. The results showed that ZD-19 can also desulfurize 4MDBT through a sulfur-specific pathway. The metabolic pathway for biodesulfurization of 4MDBT was studied, and the final product of 4MDBT biodesulfurization was determined by GC-MS, which were identified as two isomers: 4-methyl-2phenylphenol and 2-hydroxy-3-methyl-biphenyl.
 Biodesulfurization of DBT in oil-aqueous system was carried out in the ALR. The optimal gas velocity was 11.8cm/s. Slight plug-flow was formed when the gas velocity achieved 13.0cm/s, and the oil droplet diameter and the interface area decreased consequently, which were the main causes of the decreased desulfurization rate. The biodesulfurization of resting cells of ZD-19 could be proceed in the non-growth media (phosphate buffer) as efficiently as in the growth medium (BSM).  The desulfurization rate increased with the increasing of DBT concentration as well, while high DBT concentration would inhibit the activity with an optimal of 3 mmol·L-1. The results suggested that under high concentration of DBT and optimal gas velocity, the mass transfer rate was much higher compared to DBT conversion rates, when the microbial desulfurization rate was the overall rate-limiting process step.
Keywords：biodesulfurization; airlift reactor; simulated fuel oil; Mycobacterium sp.; dibenzothiophene(DBT) ; alkylated dibenzothiophenes(Cx-DBTs)