【摘要】：油品主要源自石油煉制和煤炭加工而來的產(chǎn)品,包括汽油、柴油、煤焦油、其他煤液體等,是重要的能量與化學(xué)品來源。在石油基的燃料油中,含有大量的噻吩硫(S)化物,這些油品的大量使用造成了日益嚴(yán)重的環(huán)境問題,如各地頻發(fā)的霧霾天氣和嚴(yán)重的PM2.5污染,以及酸雨等,因此燃油脫硫技術(shù)至關(guān)重要。同時(shí),對(duì)源自煤炭的煤焦油而言,其中含有大量有價(jià)值的化學(xué)品,是重要的有機(jī)化工原料,其中,酚類化合物的提取具有巨大的商業(yè)價(jià)值和應(yīng)用前景。對(duì)于燃油脫硫而言,傳統(tǒng)的加氫脫硫技術(shù)(HDS, hydrodesulfurization)反應(yīng)條件苛刻、辛烷值損失大、處理低硫油品效果差,難以滿足越來越嚴(yán)格的硫含量標(biāo)準(zhǔn)。因此,許多非加氫脫硫技術(shù)(non-HDS)應(yīng)運(yùn)而生,例如吸附脫硫(ADS, adsorptive desulfurization)、萃取脫硫(EDS, extractive desulfurization)、氧化脫硫(ODS, oxidative desulfurization)等。本論文基于Lewis酸堿作用,研究了ADS、EDS、ODS這三種技術(shù)對(duì)模型油或真實(shí)油品的脫硫情況。首先,論文研究了四種Lewis酸AlCl3、FeCl3、ZnCl2以及CuCl對(duì)3-甲基噻吩(3-MT,3-methylthiophene)、苯并噻吩(BT, benzothiophene)和二苯并噻吩(DBT,dibenzothiophene)等Lewis堿的ADS性能。研究發(fā)現(xiàn),AlCl3和FeCl3顯示良好的脫硫性能,且噻吩S化物的吸附活性順序?yàn)?-MT BT DBT。其中,AlCl3對(duì)3-MT顯示出極強(qiáng)的絡(luò)合吸附能力,在正辛烷模型油中S吸附量高達(dá)141 mgS/g,在含25 wt%甲苯的模型油中的S吸附量也可達(dá)123 mgS/go同時(shí),AlCl3也能吸附BT,并伴有BT的自聚反應(yīng),且自聚反應(yīng)有利于絡(luò)合吸附的進(jìn)行。然而,AlCl3對(duì)DBT幾乎沒有吸附活性。最后,本文利用軟硬酸堿理論來分析該過程的脫硫機(jī)理。研究發(fā)現(xiàn),噻吩S化物既是硬堿也是軟堿,S原子上與芳環(huán)平行的σ-孤對(duì)電子為硬堿區(qū),而芳環(huán)的π-電子體系則為軟堿部分。硬堿區(qū)和軟堿區(qū)的電子云密度決定了其相應(yīng)區(qū)域的堿性。為了提高硬酸AlCl3對(duì)軟堿DBT脫除效果,論文提出了利用鹵代烷烴將硬酸AlCl3軟化的策略。研究發(fā)現(xiàn),t-C4H9Cl、n-C4H9Cl、t-C4H9Br、 n-C4H9Br等鹵代烷烴與AlCl3混合,可產(chǎn)生含有碳正離子的粘性液體,稱其為碳正類離子液體(CPIL, carbonium pseudo ionic liquid)。對(duì)CPIL(如t-C4H9Cl-AlCl3),其中同時(shí)含有(CH3)3C+和溶解的AlCl3,且(CH3)3C+的中心C+為硬酸區(qū),而三個(gè)-CH3的平面為軟酸區(qū),故可與噻吩硫同時(shí)具有硬酸-硬堿和軟酸-軟堿作用,從而顯示出令人驚奇的EDS活性。只需少量的CPIL萃取劑,便可在20 min內(nèi)將3-MT、BT、DBT從正辛烷模型油、含甲苯模型油中完全脫除。CPIL絡(luò)合萃取過程中還伴隨著部分噻吩化合物的Friedel-Crafts烷基化反應(yīng)的發(fā)生。并且,CPIL能夠處理組成復(fù)雜的油品(模型汽油和真油),對(duì)輕質(zhì)油可實(shí)現(xiàn)深度脫硫,對(duì)重質(zhì)油也脫除93%以上的硫化物。其次,本文還提出利用Friedel-Crafts�；噭⿲⑧绶粤�(軟堿)硬化的策略。氯乙酰(AC, acetyl chloride)、丙酰氯(PC, propionyl chloride)、丁酰氯(BC, butyryl chloride)和Lewis酸AlCl3,通過�；磻�(yīng)使噻吩S的芳環(huán)接上-C=O基團(tuán)而被硬酸AlCl3吸附脫除,該過程被命名為酰基化脫硫(ACDS, acylation desulfurization)。研究發(fā)現(xiàn),AC-AICl3組合具有極強(qiáng)的脫硫活性,正辛烷模型油中的噻吩(T, thiophene)、BT、DBT均可在20 min內(nèi)被完全脫除。AC-AICl3優(yōu)秀的ACDS活性源于�；磻�(yīng),該反應(yīng)使芳香S化物接上堿性基團(tuán)-C=O,既增加了S化物的Lewis堿性,又增強(qiáng)了其堿硬度,這樣更容易同強(qiáng)而硬的A1C13作用。AICl3對(duì)含甲苯油中的T、BT、DBT的S吸附量隨AC的加入而變化。伴隨AC的增加,AICl3對(duì)T的吸附量略微變?nèi)?不過始終維持在120mgS/g附近；AICl3對(duì)BT的吸附量先增大后變小,最大可達(dá)75.4mgS/g; AlCl3對(duì)DBT的吸附量持續(xù)增大,從0持續(xù)上升至27.3 mgS/g。并且,ACDS對(duì)于真實(shí)油品依然有效,脫硫率可達(dá)84%以上,且硫吸附量達(dá)到56.6 mgS/g。再者,論文還研究了Lewis-Br(?)nsted混合酸對(duì)噻吩硫ODS過程的催化機(jī)理。使用Lewis酸(BF3、SnCl4、FeCl3、ZnCl2)和Bransted酸(CH3COOH)的混合酸作為催化體系,Cr(VI)或Mn(VII)為氧化劑,可實(shí)現(xiàn)在模型油中對(duì)DBT、BT、T的ODS過程。研究發(fā)現(xiàn),Lewis酸是混合酸的核心,其跟CH3COOH中O原子發(fā)生絡(luò)合作用,改善了混合酸的Bronsted酸性,促進(jìn)了Cr(VI)的溶解,并催化了噻吩化合物的氧化。該過程中,DBT被氧化成DBTO2,而BT和T除了S被氧化之外,雙鍵也被氧化,從而形成了一些復(fù)雜的氧化產(chǎn)物。采用量化方法計(jì)算了相關(guān)含雙鍵物質(zhì)的鍵級(jí)和π-軌道電子占用,分析得出這些物質(zhì)的雙鍵反應(yīng)活性順序?yàn)椋罕郊妆�、DBTO2 DBT T BT BTO2 TO2環(huán)己烯。最后,通過調(diào)變混合酸中的Lewis酸含量和種類,可達(dá)到調(diào)控混合酸體系酸性的目的,進(jìn)而有效控制噻吩硫的氧化選擇性。對(duì)于煤焦油抻酚而言,傳統(tǒng)的堿洗法產(chǎn)生大量廢堿,且工藝復(fù)雜,成本較高。本文基于酸堿作用,旨在通過化學(xué)吸附的方式,將苯酚從油中分離出來。論文研究了AlCl3、六次甲基四胺(HMT, hexamethylenetetramine)和三氮唑通過Lewis酸堿或氫鍵作用對(duì)模型油中苯酚的吸附提取性能,并對(duì)吸附規(guī)律做了實(shí)驗(yàn)考查和理論分析。研究發(fā)現(xiàn),本文所選的吸附劑都能吸附模型油中的苯酚：HMT對(duì)酚的吸附能力最強(qiáng),吸附量超過3500(mg/g-sorbent),其不溶于油且可重復(fù)利用,是一種高效的酚吸附劑；AlCl3與苯酚間為強(qiáng)的Lewis酸堿作用,其作用能達(dá)-111.5 kJ/mol,難以重復(fù)利用；三氮唑?qū)Ψ拥奈搅坎淮?且有油溶性。另外,萘和BT的存在不影響HMT對(duì)苯酚的吸附量,反而加速了HMT對(duì)苯酚的吸附,這是因?yàn)檩�、BT分別與HMT、苯酚皆有弱的相互作用,且吸附的活化能也隨兩者的加入而降低。然而,喹啉的存在使HMT對(duì)苯酚的吸附量大幅降低至1000mg/g以下,因?yàn)猷c苯酚具有較強(qiáng)的相互作用,作用能達(dá)-31.2kJ/mol。最后,論文還基于現(xiàn)有實(shí)驗(yàn)數(shù)據(jù),評(píng)價(jià)了兩套Lewis酸(AlCl3和Cu(I)-Y沸石)脫硫體系的技術(shù)經(jīng)濟(jì)可行性。通過兩套脫硫工藝過程的技術(shù)參數(shù)的估算發(fā)現(xiàn),兩套脫硫體系在技術(shù)上均是可行的。通過對(duì)兩套脫硫工藝過程的加工成本進(jìn)行核算后發(fā)現(xiàn),兩個(gè)脫硫體系各有所長(zhǎng),AlCl3體系處理Ts類硫化物的成本較低,Cu(I)-Y沸石體系則處理BTs類硫化物的成本較低。另外,通過對(duì)兩套脫硫工藝過程的財(cái)務(wù)評(píng)價(jià)發(fā)現(xiàn),它們?cè)诮?jīng)濟(jì)性上均是可行的,有進(jìn)一步工業(yè)放大的前景。
[Abstract]:Oil products, mainly from petroleum refining and coal processing, including gasoline, diesel oil, coal tar, and other coal liquids, are important sources of energy and chemicals. As the weather and serious PM2.5 pollution, acid rain and so on, fuel desulfurization technology is very important. At the same time, coal tar from coal, which contains a large number of valuable chemicals, is an important organic chemical raw materials, in which the extraction of phenolic compounds has great commercial value and application prospects. The traditional hydrodesulfurization technology (HDS) is difficult to meet the increasingly stringent sulfur content standards due to its harsh reaction conditions, high loss of octane number and poor treatment effect on low sulfur oils. Therefore, many non-hydrodesulfurization technologies such as adsorptive desulfurization (ADS) and extractive desulfurization (EDS) have emerged as the times require. Desulfurization, oxidative desulfurization and so on. Based on Lewis acid-base interaction, this paper studied the desulfurization of model oil or real oil by ADS, EDS and ODS. Firstly, four kinds of Lewis acid AlCl3, FeCl3, ZnCl2 and CuCl p-3-methylthiophene (3-MT, 3-methylthiophene), benzothiophene (BT, BT, ODS) were studied. ADS properties of Lewis bases such as benzothiophene and dibenzothiophene were studied. AlCl3 and FeCl3 showed good desulfurization performance, and the order of adsorption activity of thiophene S compounds was 3-MT BT DBT. Among them, AlCl3 showed strong complex adsorption ability to 3-MT, and the adsorption capacity of S in n-octane model oil was as high as 141 mg S/g, and in 25-containing n-octane model oil. The adsorption capacity of S in wt% toluene model oil can reach 123 mg S/go. At the same time, AlCl3 can also adsorb BT with BT self-polymerization, and the self-polymerization is conducive to complexation adsorption. However, AlCl3 has little adsorption activity on DBT. Finally, the desulfurization mechanism of the process is analyzed by using the theory of hard and soft acids and bases. The_-lone pair electrons parallel to the aromatic ring on S atom are hard base and the_-lone pair electrons of aromatic ring are soft base. The density of electron cloud in hard base and soft base regions determines the alkalinity of the corresponding region. In order to improve the effect of hard acid AlCl3 on soft base DBT removal, halogenated alkanes are proposed in this paper. It is found that the mixing of halogenated alkanes such as t-C4H9Cl, n-C4H9Cl, t-C4H9Br, n-C4H9Br with AlCl3 can produce viscous liquids containing carbon cations, which are called carbon cationic ionic liquids (CPIL, carbonium pseudo ionic liquids). The hard acid region and the three-CH 3 planes are soft acid region, so they can react with thiophene sulfur simultaneously with hard acid-hard base and soft acid-soft base, thus showing surprising EDS activity. With a small amount of CPIL extractant, 3-MT, BT and DBT can be completely removed from n-octane model oil and toluene model oil in 20 minutes. With the occurrence of Friedel-Crafts alkylation of some thiophene compounds, CPIL can be used to treat complex oils (model gasoline and real oil), which can achieve deep desulfurization of light oils and removal of more than 93% of sulfides from heavy oils. Secondly, Friedel-Crafts acylation reagent is proposed to harden thiophene sulfur (soft base). The strategy. Chloroacetyl chloride (AC, acetyl chloride), propionyl chloride (PC), butyryl chloride (BC, butyryl chloride) and Lewis acid AlCl 3, by acylation reaction to make thiophene S aromatic ring on - C = O group and by hard acid AlCl 3 adsorption and removal, the process is named acylation desulfurization (ACDS, acylation desulfurization). The study found that, AC-AICl The best ACDS activity of AC-AICl3 derives from the acylation reaction, which makes the aromatic S compound join with the basic group - C=O. This reaction not only increases the Lewis alkalinity of the S compound, but also enhances its base hardness, so it is easier to be the same as the strong one. The adsorption of T, BT and DBT by AICl3 changed with the addition of AC. With the increase of AC, the adsorption of T by AICl3 weakened slightly, but remained around 120 mg S/g. The adsorption of BT by AICl3 increased first and then decreased to 75.4 mg S/g. The adsorption of DBT by AlCl3 increased continuously from 0 to 0. Furthermore, the catalytic mechanism of Lewis-Br (?) nsted mixed acid for thiophene sulfur ODS process was studied. The mixed acid of Lewis acid (BF3, SnCl4, FeCl3, ZnCl2) and Bransted acid (CH3COOH) was used as catalytic system, and Cr (VI) was used as catalytic system. It is found that Lewis acid is the core of the mixed acid. It complexes with O atom in CH3COOH, improves Bronsted acidity of the mixed acid, promotes the dissolution of Cr (VI) and catalyzes the oxidation of thiophene compounds. In addition to S being oxidized, the double bonds are also oxidized to form some complex oxidation products. The bond order and the pi-orbital electron occupation of the related double bonded substances are calculated quantitatively. The order of the double bond reactivity of these substances is as follows: benzene, DBTO2 DBT BTO 2 TO2 cyclohexene. The content and type of Lewis acid can be adjusted to control the acidity of mixed acid system, and then the oxidation selectivity of thiophene sulfur can be effectively controlled. For coal tar benzophenol, the traditional alkali washing method produces a large number of waste alkali, and the process is complex and the cost is high. In this paper, the adsorption and extraction properties of AlCl3, hexamethylenetetramine (HMT) and triazole for phenol in model oil by Lewis acid-base or hydrogen bonding were studied, and the adsorption rules were investigated experimentally and analyzed theoretically. The adsorption capacity is the strongest, the adsorption capacity is more than 3500 (mg/g-sorbent), it is insoluble in oil and can be reused, is an efficient phenol adsorbent; AlCl3 and phenol are strong Lewis acid-base interaction, its role can reach - 111.5 kJ/mol, difficult to reuse; triazole adsorption of phenol is not large, and oil-soluble. In addition, the presence of naphthalene and BT does not affect the HMT. The adsorption capacity of phenol accelerates the adsorption of phenol on HMT, because naphthalene, BT and HMT, phenol have weak interaction, and the adsorption activation energy decreases with the addition of both. However, the adsorption capacity of HMT on phenol is greatly reduced to below 1000mg/g due to the strong interaction between quinoline and phenol. Finally, based on the available experimental data, the technical and economic feasibility of two sets of Lewis acid (AlCl3 and Cu (I) - Y zeolite) desulfurization systems was evaluated. The technical parameters of the two sets of desulfurization processes were estimated to show that the two sets of desulfurization systems were technically feasible. The cost calculation shows that the two desulfurization systems have their own advantages. The cost of treating Ts sulfides by AlCl3 system is lower than that by Cu(I)-Y zeolite system, and the cost of treating BTs sulfides by Cu(I)-Y zeolite system is lower. View.
【學(xué)位授予單位】：北京化工大學(xué)
【學(xué)位級(jí)別】：博士
【學(xué)位授予年份】：2015
【分類號(hào)】：TE624.55
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本文編號(hào)：2237165