Microbial desulfurization of fuel oil

Culture conditions of desulfurization microbes were investigated with a bioreactor controlled by computer.Factors such as pH, choice of carbon source, optimal concentrations of carbon, nitrogen and sulfur sources were determined. The addition of carbon in a culture with a constant pH greatly improved the growth of Rhodococcus. Cells and cell debris from microbes rested using a sulfur- specific pathway were used to desulfurize diesel oil treated by hydrodesulfurization (acquired from the Research Institute of Fushun Petroleum with total sulfur level at 205 μg/mL).Strains 1awq, IG, X7B, ZT, ZCR, and a mixture of No. 5 and No. 6, were used in the biodesulfurization process. The reduction of total sulfur was between 10.6% and 90.3%.     

Effects of aqueous media on microbial removal of sulfur from dibenzothiophene in the presence of hydrocarbons

The existence of sulfur in the petroleum would erode the transport lines and poison the chemical catalysts. In addition, it is the main cause of air pollution and the for-mation of acid rain. At present, hydrodesulfurization (HDS) is the commonly used technology for fuel desulfu-rization. HDS has the disadvantages of high cost of ma-nipulation and equipment investment. Furthermore, HDS is difficult to remove the sulfur from condensed thio-phenes such as dibenzothiophene (DBT). These forms…     

柴油脱硫菌的筛选及发酵条件研究*

首先以二甲基亚砜为唯一硫源,通过初筛,筛选出28株菌株,再以二苯并噻吩（DBT）为唯一硫源复筛,筛选出降解DBT较好的菌株HT1。菌株液体发酵实验表明,菌株HT1生长的最适pH值为6.5～7.5,最佳温度30℃;酸性和碱性条件均对菌株的生长有抑制作用,二苯并噻吩降解能力降低;以葡萄糖作为碳源菌株生长最好,但存在底物抑制作用,以甘油作为碳源时,菌株生长及DBT降解能力略低,但不存在底物抑制作用;菌株HT1既能利用有机氮源也能利用无机氮源,但利用有机氮源的能力远远大于无机氮源,对DBT的降解能力却正好相反,其中以硝酸铵作为氮源时,对DBT降解能力最大。最终确定甘油为最佳碳源,浓度为5 g/L,硝酸铵为生长氮源,最佳浓度为2 g/L。     

基于转移指令特性的动态翻译算法

摘要： 针对传统方法统一转译转移指令导致翻译器效率较低的问题,基于转移目标地址在函数内外的不同特征,提出了直接映射和指令类型转译策略组合的动态翻译方法.对函数内转移指令,直接采用目标架构中对应的分支指令进行映射,通过转移前后指令翻译码的无缝链接,高效转译了条件分支指令,且无需生成源寄存器到内存同步指令;对函数间转移指令,区别对待函数转移和其他转移指令,通过将源程序函数转移指令属性继承给翻译码以提高目标机转移预测器准确率.基于EEMBC(Embedded Microprocessor Benchmark Consortium)测试基准的实验表明,该方法使转移指令翻译码执行指令数平均减少58.9%,转移预测器命中率平均提高80.7%,翻译器整体性能提高12.3%.     

基于DBT分类算法的银行贷款风险评估

银行贷款风险评估一直是金融界高度关注的主要问题,现有方法主要包括K-means聚类、BP神经网络、简单决策树、VAR方法等多种风险评估算法。但对于客户属性值缺失的案例,上述方法就很难达到良好的效果。为了解决属性值缺失的风险评估问题。提出了一种基于贝叶斯决策树算法的贷款风险评估算法（DBT ）,实验结果证明了该算法的有效性。     

一株红球菌模拟油相生物脱有机硫的研究

从一株走“4S”途径的红球菌1awq出发,研究了生物催化剂的模拟油相反应.在生长过程中,以正十四烷配制的DBT为惟一硫源培养的细胞的菌体质量浓度能达到6.7gL,比用无水乙醇配制的DBT培养的要高出1倍多.在休止细胞模拟油相和水相反应中,油水体积比为1∶3的模拟油相反应能生成2.56mmolL的终产物2HBP,比水相生成的0.44mmolL的2HBP要高出4倍多.在20%～60%的模拟油相反应中,DBT的降解率均能达到90%以上.在含高浓度的DBT的模拟油相反应中,休止细胞能够在24h内降解100%的10mmolL的DBT,97.1%的20mmolL的DBT,分别能降解50.4%、48.7%和39.8%的30mmolL、40mmolL和50mmolL的DBT.20mmolL的C14模拟油相反应中2HBP生成速率能达到0.373μmol·g-1·min-1,40mmolL和50mmolL的也分别能达到0.268和0.213μmol·g-1·min-1,在柴油的实际脱硫中有好的应用前景.     

Preparation of microbial desulfurization catalysts

A Rhodococcus sp. lawq, a bacterium isolated from the soil cleaving the C—S bond of dibenzothiophene (DBT) via specific pathway, was investigated for cell growth and for its role in desulfurization. Clearly, the end product, 2-hydroxybiphenyl, inhibited the growth of the strain, the synthesis of the desulfurization enzymes, and the activity of the enzymes. The effects of sulfate on the DBT degradation enzymes were examined in the Rhodococcus sp. lawq growth system with DBT; the sulfate served, concurrently, as the sulfur source. The condition of the resting cells that were used in desulfurization, was also studied. The optimal concentration of the resting cells and the reaction conditions were determined. It was documented that there is no difference between desulfurization activity for resting cells cultured with sulfate as the sole sulfur source and that with the mixture of DBT and sulfate as the sulfur source.     

二丁基锡在水表面微层水中的吸附行为

采用ＧＣ／ＡＡＳ联用系统研究了海河河口表面微层水中二氯化二丁基锡（ＤＢＴ）在悬浮物上的吸附行为,在低浓度下,其吸附率基本符合Ｆｒｅｕｎｄｌｉｃｈ吸附等温线,对各种影响因素的研究表明,ｐＨ对ＤＢＴ的吸附有很大程度,在ｐＨ６．０时悬浮物对其吸附最强,盐度对ＤＢＴ吸附有一定的影响,在盐度为７．５‰时悬浮物地其吸附最弱,另外,悬浮物浓度对ＤＢＴ的吸附也有重要影响。     

免焙烧制备WP/SiO2加氢脱硫催化剂

采用等体积浸渍法制备焙烧和免焙烧的催化剂前驱体,用H2程序升温还原法制备焙烧和免焙烧的WP/SiO2催化剂.对制备的催化剂进行XRD和N2物理吸附表征,并用质量分数为0.8%的二苯并噻吩/十氢萘溶液来考察催化剂的加氢脱硫反应活性.与焙烧的WP/SiO2(C-WP/SiO2)催化剂相比,NC-WP/SiO2具有较大的比表面积和孔容;反应后,两种催化剂的比表面积和孔容均降低.在NC-WP/SiO2上,DBT的转化率略低于C-WP/SiO2,但均随着温度的增加而升高;随着温度的升高,两种催化剂加氢中间体的选择性降低,直接脱硫产物BP的选择性升高,说明增加温度有助于含硫化合物的脱硫.340℃,C-WP/SiO2催化DBT的反应速率(0.33 mol·g－1·min－1)略高于NC-WP/SiO2(0.28 mol·g－1·min－1);在NC-WP/SiO2上,DBT主要以DDS路径脱硫,而在C-WP/SiO2上,加氢活性较高.