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1.
粒径对煤在H2/Ar等离子体中热解的影响   总被引:11,自引:1,他引:10  
对粒径在H2/Ar等离子体煤热解制乙炔中的影响进行了研究,得到了煤的粒径与煤的裂解程度(转化率)、乙炔收率、乙炔在产品气体中摩尔分数和反应器壁结焦的关系,并且在考虑各种因素的制约下,对如何选择最佳粒径和粒径分布的问题进行了讨论。根据煤等离子体热解制乙炔反应器壁结焦的机理和煤粒径是影响反应器内结焦的重要因素,提出了进料粒径双峰分布缓解煤等离子体热解制乙炔装置结焦的新方法,实验证明该方法可行。  相似文献   

2.
煤加氢热解研究:Ⅰ.宁夏灵武煤加氢热解的研究   总被引:22,自引:14,他引:8  
本文在100克固定床反应器中对宁夏灵武不粘结煤的加氢热解进行了研究,反应温度773~1070K,压力0.2~4MPa,反应产物的收率与组成和惰性气氛下的热解进行了比较。研究结果指出:在氢气气氛下热解转化率和焦油收率大大提高,表明了在氢压下煤热解初期生成的自由基与氢反应,抑制了自由基间的相互结合,而生成较多的低分子化合物。与惰性气氛下热解相比,温度 873K和压力为3MPa下的加氢热解焦油收率提高2  相似文献   

3.
煤质对H2/Ar等离子体热解制乙炔的影响   总被引:3,自引:1,他引:3  
选取12种不同变质程度的煤,通过等离子体热解实验考察了煤的挥发分产率、煤中氧质量分数、灰分产率对乙炔收率和结焦的影响。研究结果表明,挥发分产率为30%~40%的烟煤,热解时具有较高的乙炔收率;含氧量越高的煤,生成的碳氧化物越多,相应的乙炔收率较低;煤中的矿物质与乙炔收率之间并不存在相关性,但煤中的矿物质有利于CO的生成。影响结焦量的主要因素与煤的矿物质密切相关,煤中掺入二氧化硅和天然河沙能够明显增加结焦量,改变结焦形态。  相似文献   

4.
几种烃化合物在氮热等离子体中的热解   总被引:3,自引:0,他引:3  
研究了数种烃包括液态苯和甲苯以及气态的四甲烷,乙烯及乙炔在氮热等离子体中的热解行为,结果发现,所有烃人合物在氮等离子体中均发生强烈的分解反应,生成大量炭黑和气体。气体产物中的主要成分是氢,乙炔和丙炔腈,在液态烃苯和甲苯的热解产物中不含有甲烷及乙烯等小分子烃,乙炔的浓度与丙炔腈的含量有关,丙炔腈的含量高时,乙炔的浓度低,反之亦然,所制得的炭黑粒细小,粒度分布范围产窄,具有较强的吸附性能,其确值为14  相似文献   

5.
本文对二苯甲烷、二苯乙烷、二苯醚、苯基苄基醚和二苄醚等五个与煤的化学结构和煤液化有关的模型化合物在供氢溶剂四氢萘中、N_2压力为50—60大气压下的热解反应动力学及反应机理进行了研究。结果表明: (1) 二苯甲烷和=苯醚在435 ℃/2 h条件下依然比较稳定, 这意味着, 在实际煤液化过程中, C—C、C—O键的断裂不能靠这些简单结构方式的裂解加以解释; (2) 二苯乙烷和苯基苄基醚的热解有一级反应特征, 其反应机理为自由基过程, 反应速度方程和速度常数的理论计算与实验结果完全一致; (3) 二苄醚的热解可用分子内氢转移模型得到较好解释, 热解产物苯甲醛进一步脱氧生成甲苯, 这可能是煤液化中除氧的一条很重要的途径。  相似文献   

6.
本文在5g固定床反应器中对神府榆家梁煤的加氢,MoS_2催化加氢及模拟焦炉气(50%H_2-50%CH_4)下的热解进行了研究,反应温度793~973K,压力0.1~15MPa,升温速率5K/s。实验结果表明,由于煤加氢热解反应受传质控制,因此,不同反应器与工艺参数对热解反应影响很大;热解产物的焦油/气体收率比值可较好反映氢的有效利用率;高温和高压有利于煤加氢气化反应,导致氢耗增加,氢有效利用率下降;催化剂的存在不仅促进加氢反应,而且也加快了芳环开环及加氢气化反应;甲烷在本研究的温度和压力条件下相当于惰性组分,加氢热解反应取决于氢分压,说明以焦炉气代替氧气进行煤加氢热解是可行的。  相似文献   

7.
本文在5g固定床反应器中对神府榆家梁煤的加氢,MoS2催化加氢及模拟焦炉气下的热解进行了研究,反应温度793-973K,压力0.1-15MPa,升温速率5K/s。实验结果表明,由于煤加氢热解反应受传控制,因此,不同反应器与工艺参数对热解反应影响很大;热解产物的焦油/气体收率比值可较好反映氢的有效利用率;高温和高压有利于煤加氢气化反应,导致氢耗增加,氢有效利用率下降;催化剂的存在不仅促进加氢反应,而  相似文献   

8.
利用加压管式反应器对准东煤进行了一系列热解实验,并采用溶剂逐级萃取的方法研究了煤中各赋存形态钠在不同热解温度、停留时间及其压力下的变迁规律。研究发现,原煤中钠主要是以水合离子态和钠长石的形式存在,有机态钠含量较少。在500-700℃时,随着挥发分的释放,水可溶性钠结合到煤焦的碳基质上,转化为盐酸可溶但水不可溶性的钠,少量有机钠会挥发至气相中。在700-900℃时,可溶性钠与高岭土等矿物质反应生成盐酸不可溶性钠。1 000℃时,钠的挥发量显著增加;部分高岭土与方解石分解生成的氧化钙反应生成钙长石,抑制了可溶性钠与高岭土之间的反应。煤中各形态钠的变迁主要发生在热解初期,与挥发分的释放同时进行。提高热解压力对钠的变迁行为没有影响。  相似文献   

9.
以秸秆为原料,在两段式固定床反应器上模拟层燃工况进行热解实验,研究了氧气对热解过程中燃料氮迁移与转化的影响。通过对焦油中含氮化合物种类与含量的GC-MS分析,提出了热解过程中燃料氮转化的反应路径,并分析了氧气的影响。与惰性气氛下相比,氧气的引入降低了焦油与焦炭的产率,从而降低了焦油与焦炭中氮的分配比,增加了气体组分中氮的分配比。以蛋白质和氨基酸作为燃料氮的禀赋形态,其在热解过程中发生一系列一次反应,生成酰胺、胺类等初级焦油产物。初级焦油发生二次反应,进一步生成腈类及含氮杂环化合物等二级焦油产物。有氧条件下,焦油中酰胺、胺类等初级焦油成分的含量显著降低,腈类及含氮杂环化合物等二级焦油成分的含量升高。  相似文献   

10.
常压程序升温热解-质谱系统在煤脱羧过程中的应用   总被引:1,自引:0,他引:1  
设计了在线监测煤和其它含高挥发分组份样品的热解气体的反应器,将此反应器与商品型质谱(MS)联用,建立了常压程序升温热解-质谱(AP-TPP-MS)系统。用模型化合物和真实样品检验了该系统的可靠性和重复性,并探讨了通过预处理前后煤热解时CO2的逸出情况来反映煤脱羧效果的可行性。结果表明,此系统用于模型化合物热解时能获得响应好、重叠拖尾少、对称性好的气体逸出峰;用于氧化煤时能清晰可辨地显示同一热解气体的多个逸出峰;系统的稳定性和重复性较好。可利用此系统监测CO2的逸出情况,反映预处理对煤的脱羧效果。  相似文献   

11.
In the context of the preparation of camptothecin and luotonin A analogs, the synthesis of some key keto-precursors and their use in Friedländer condensation are described. This paper also focuses on the stability of these keto intermediates and emphasizes the major differences between indolizinones and pyrroloquinazolinones series. Noteworthy is also the report of some original structures isolated as by-products of some experiments.  相似文献   

12.
Different approaches for the synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives from simple amino acids have been investigated. A library of 33 precursors for the preparation of N-hydroxy pyrazinones was obtained in moderate to good yields.  相似文献   

13.
KMnO4-mediated oxidative CN bond cleavage of tertiary amines producing secondary amine was introduced, which was trapped by electrophiles (acyl chloride and sulfonyl chloride) to form amides and sulfonamides. The reaction could take place at mild condition, tolerating a wide range of function groups and affording products in moderate to excellent yields.  相似文献   

14.
The review contains a concise historical account and information on the most significant researches undertaken by the staff at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences on the Chemistry of Heterocyclic Compounds. Dedicated to Academician of the Russian Academy of Sciences B. A. Trofimov on his 70th jubilee. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1443–1502, October, 2008.  相似文献   

15.
A general synthesis of previously unknown semicarbazone-based α-amidoalkylating reagents, 4-(tosylmethyl)semicarbazones, has been developed. The synthesis involved three-component condensation of semicarbazones of aliphatic or aromatic aldehydes with the same or other aldehydes and p-toluenesulfinic acid. The scope and limitations of this reaction were investigated. The compounds obtained were demonstrated to be an efficient α-(4-semicarbazono)alkylating agents. They were reacted with H- (sodium borohydride), O- (sodium methylate), S- (sodium phenylthiolate), N- (pyrrolidine, sodium succinimide), P- (trialkyl phosphites), and C-nucleophiles (sodium diethyl malonate) to give the corresponding products of the tosyl group substitution, 4-substituted semicarbazones, including analogues of nitrofurazone. Among the prepared compounds tested in vitro for antibacterial and antifungal activity, three nitrofuryl-containing semicarbazones exhibited high biological activities with minimum inhibitory concentration (MIC) values of 8–32 μg/mL.  相似文献   

16.
The highly regioselective Buchwald–Hartwig amination at C-2 of the cheap and readily accessible reagent, 2,4-dichloropyridine with a range of anilines and heterocyclic amines is described. This new methodology is robust and provides a facile access to 4-chloro-N-phenylpyridin-2-amines on 0.25 mol scale. These intermediates undergo a further Buchwald–Hartwig amination at higher temperature to enable rapid exploration of the chemical space at C-4 and to provide a library of 2,4-bisaminopyridines.  相似文献   

17.
A small library of new chiral bidentate hydroxyalkyl-imidazolium salts 1 is conveniently synthesized on multi-gram scale from inexpensive and commercially available chiral pool amino acids. The corresponding carbenes, generated by deprotonation of imidazolium salts 1, in combination with palladium(II) chloride were tested in the Mizoroki–Heck coupling reaction. The most significant results in terms of yields and reactivities were achieved with low catalyst loading. The catalytic activities of these imidazolium salts were also investigated in the asymmetric addition of diethylzinc to benzaldehyde. The use of MgO nanoparticles as an additive in conjunction with these ligands played a crucial role in increasing the efficiency of these reactions.  相似文献   

18.
19.
A new and simple synthesis of novel N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates, which exist in equilibrium with their 4-oxo tautomers, has been developed in two steps starting from N-protected α-amino acids. The key intermediates are enaminones, which can also be isolated, characterized, and used for the construction of other functionalized heterocycles, before they spontaneously decompose to pyrrole products. 4-Hydroxypyrroles are prone to partial aerial oxidation but can be efficiently alkylated or reduced to stable polysubstituted pyrrolidine derivatives.  相似文献   

20.
The chemoselectivity in the intramolecular CH insertion of various diazosulfonamides has been experimentally studied. The results reveal that the aliphatic 1,4-, 1,5-, or 1,6-C(sp3)?H insertions of diazosulfonamides are not accessible, while the aromatic 1,5-C(sp2)?H insertion can be realized specifically by adjusting the diazo-adjacent group. In addition, the general chemoselectivities in the intramolecular CH insertions of diazosulfonyl compounds are summarized. Generally, diazosulfones undergo both aromatic 1,5-C(sp2)?H and aliphatic 1,5- and 1,6-C(sp3)?H insertions, while diazosulfonates undergo aliphatic 1,5- and 1,6-C(sp3)?H insertions. However, diazosulfonamides only undergo aromatic 1,5-C(sp2)?H insertion.  相似文献   

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