稀土改性HZSM-5分子筛催化裂解混合C4烃制低碳烯烃性能的研究

用浸渍法制备了稀土改性HZSM-5分子筛催化剂(简称RE/HZSM-5),研究了RE/HZSM-5对混合C4烃(包括C4烷烃和C4烯烃)裂解活性及低碳烯烃收率的影响.结果表明,RE改性后HZSM-5分子筛催化剂的裂解活性明显增加,轻稀土改性HZSM-5分子筛比重稀土改性的表现出更好的增产低碳烯烃裂解性能.在0.1MPa,重时空速(WHSV)=1.2×104 mL/h*g-1条件下,轻稀土La、Pr、Nd、Sm、Gd改性HZSM-5分子筛催化剂上混合C4烃催化裂解产物中乙烯和丙烯总收率在625℃时达到最高,分别为54.66%、54.32%、53.32%、54.15%和54.06%,比相同条件下未改性的HZSM-5高3%～4%.重稀土中只有Yb/HZSM-5表现出较好的裂解活性,裂解产物中乙烯和丙烯总收率在600℃时达到最高,为54.80%.用红外光谱(FT-IR),氨程序升温脱附(NH3-TPD)和吡啶吸附红外光谱法(Py-IR)法对RE/HZSM-5分子筛进行了表征,结果表明催化剂的总酸量、B酸与L酸的比值与催化活性之间存在密切关系.     

中空纤维膜组件分离酸性气体

研究了气体膜分离与溶剂吸收相结合的分离技术,以ＮａＯＨ不溶液为吸收剂,在中空纤维膜组件中实现二氧化硫气体的选择性吸收,研究了三三种不同结构的疏水性聚丙烯中空纤维膜组件中吸收剂浓度、液速、气速、气液两相在膜组内的流程、膜结构等对分离过程的影响,根据膜的实际参数确定了多孔膜的曲率因子,总传系数的计算民实验值相符。     

硅铝磷酸盐催化剂在MTO优化微反应装置评价研究

有色金属产品向高值化和高端产品转化是有色行业一个重要的发展趋势,其中新能源和煤化工方面的催化剂是一个重要的新兴领域。就我国取得突破进展的煤制烯烃装置中,在更换工业化催化剂之前,为了更准确的掌握每批催化剂的性能指标,保证工业生产的稳定运行,事先进行微反评价尤为重要。本文以典型的硅铝磷酸盐SAPO-34为例,结合目前工业上运行的工业化设备,提出了改进的反应器评价装置,并对甲醇转化乙烯过程进行了评价研究,主要讨论了甲醇浓度、反应温度和空速等参数的影响,为开发新型催化剂提供一种借鉴的实验研究和工业化评价方法。     

苯与乙烯或丙烯烷基化反应精馏过程的稳态模拟

采用平衡级模型研究了苯单独与乙烯或丙烯烷基化反应的精馏过程.计算的塔内温度和液相组成分布与已有实验和非平衡级模拟吻合较好,表明平衡级方法能够准确有效地描述非均相催化反应精馏.在乙烯丙烯同时进料时,考察了苯烯比、苯质量空速、回流比和塔顶压力对烯烃转化率、热负荷和每年总投资的影响.计算表明,当苯与乙烯丙烯进料比分别为3.5和2.0、空速2h-1、回流比10.0、压力0.71 MPa、催化剂填装分率18%时,乙烯和丙烯的转化率均能达到100%.同时,反应精馏塔的TAC小于乙烯丙烯分别进行烷基化反应精馏的值,故能降低成本.后续常规精馏塔分离的馏出物中,异丙苯、乙苯和苯浓度均可达到95%以上.     

铁碳合金薄带气固反应脱碳工艺

提出了高炉铁水双辊连铸薄带十高温气固反应脱碳,生产钢带的全新工艺流程.实验以高碳铁碳合金板带为研究对象,在Ar-H2-H2O气氛下可控气氛管式炉内,利用高温气固反应脱碳机制,探索铁碳合金固态下脱碳而铁基不氧化的可行性,确定可控气氛下脱碳的温度和气氛条件范围.实验结果表明:气氛条件对铁的氧化有显著影响,当水浴温度不大于60℃或气体流量不大于300 mL/min时,脱碳后基体中不存在铁的氧化物;当水浴温度达到70℃或气体流量达到450mL/min时,脱碳后基体中出现铁的氧化物,此时由于铁氧化的出现降低了脱碳效果.     

对流扩散对多孔介质气固反应的影响

针对填充床中的气固反应aA(g) bB(s)=cC(g) dD(s),在微元体动力学研究的基础上,考虑到气体的压缩性和惰性组分的存在,从渗流力学观点出发,导出了反应气体与产物气体的非线性对流反应扩散方程和混合流体渗流方程,用有效容积法求方程的数值解,通过实例计算,分析了不同条件下的反应转化情况.结果表明,颗粒尺度和反应器长度对反应进程有明显影响,这些影响可以用Thiele数、Peclet数及它们的比值来衡量,适当选取颗粒尺度和反应器长度可以改善反应器性能.     

小型沸腾炉二氧化硫烟气脱硫研究

本文针对小型沸腾炉ＳＯ２烟气的净化处理工艺，采用湿法处理高ＳＯ２含量烟气。探讨了吸收剂的吸收率与烟气中ＳＯ２含量、吸收剂浓度、液气体积比值及吸收液循环利用率的关系。     

TS-1后处理改性对其丁酮氨氧化反应的影响

采用叔丁胺和四丙基氢氧化铵混合碱溶液对TS-1(titanium silicalite-1)分子筛进行后处理改性,以构建介孔结构和调变分子筛中Ti物种的存在状态,从而提高TS-1分子筛的催化活性。通过系列表征手段重点研究了叔丁胺浓度和改性时间对TS-1分子筛物化性质以及丁酮氨氧化反应性能的影响。结果表明,TS-1经过混合碱溶液改性后,TS-1分子筛中产生了一定的介孔结构,同时锐钛矿Ti O2几乎完全脱除,从而显著提高了其丁酮氨氧化反应活性。对于不同叔丁胺浓度和时间后处理改性的TS-1分子筛,相对结晶度以及不同Ti物种(骨架Ti、六配位非骨架Ti和锐钛矿Ti O2)的含量是决定其活性的关键因素。以0. 2 mol·L-1叔丁胺和TPAOH的混合溶液,在170℃下改性24 h得到的TS-1具有最好的丁酮氨氧化反应活性,丁酮转化率和丁酮肟选择性分别为100%和98. 6%。     

1 mm铁碳合金薄带气-固反应脱碳试验

 为了研究1 mm铁碳合金薄带气-固反应脱碳动力学以及探索不同温度对薄带脱碳效果的影响。以初始碳质量分数为4.2%、厚度为1 mm的铁碳合金薄带为研究对象,在气体流量为400 mL/min、[pH2O/pH2]为0.85的Ar-H2-H2O混合气氛条件下,以高温气-固反应形式开展脱碳试验研究。结果表明,提高脱碳温度可以明显提高脱碳效果,在1 413 K温度条件下脱碳30 min可以将碳脱至0.12%。宏观脱碳反应近似为表观一级反应,脱碳反应表观活化能为157.9 kJ/mol。脱碳反应初期主要受控于表面化学反应,后期碳在薄带内部的扩散成为主要限制性环节。     

稀土氧化物与二氧化硫反应的热力学研究

本文对稀土氧化物与ＳＯ２的气固相反应进行了系统的热力学计算研究，得到了系统化的含硫气体平衡分压曲线；研究表明，从热力学上讲，当温度低于２３７℃时，所有稀土氧化物都可作为烟道气干法脱硫的吸收剂；可以使用ＣｅＯ２通过干吸收生成Ｃｅ（ＳＯ４）２和热再生循环过程实现固体再生干法脱除烟气中的ＳＯ２，其吸收ＳＯ２和再生ＣｅＯ２的温度范围分别为１００～４４０℃和７１５～８６５℃。     

Determination of mitoxantrone in mouse whole blood and different tissues by high-performance liquid chromatography

A high-performance liquid chromatographic (HPLC) method was developed for the specific determination of mitoxantrone (MTO) in whole blood and different tissues of mice (liver, heart, spleen, kidneys). MTO was extracted into dichloromethane with ametantrone (AMT) as internal standard. The different tissues were homogenised in citrate buffer (pH 3.0) containing 20% ascorbic acid. Separation of MTO and AMT was carried out using a Nucleosil C18 column. The mobile phase consisted of acetonitrile (33%) and 0.16 M ammonium formate buffer, pH 2.7. UV detection was used at 658 nm. Baseline separation of AMT and MTO was achieved in all matrices. The calibration curves were linear in all matrices (r > 0.999) in the concentration range of 2-200 micrograms/l for whole blood and 2-700 micrograms/l for tissue homogenates, respectively. The within-day and between-day precision studies showed good reproducibility with coefficients of variation below 4.5% for whole blood and below 10% for tissue homogenates, respectively. The extraction efficiencies of MTO are 60% in whole blood and 38% in tissue homogenates. The method described is suitable for pharmacokinetic studies on the distribution of MTO in different tissues of mice.     

Comparative pharmacokinetic and cytotoxic analysis of three different formulations of mitoxantrone in mice

Two liposomal formulations of mitoxantrone (MTO) were compared with the aqueous solution (free MTO) in terms of their pharmacokinetic behaviour in ICR mice and cytotoxic activity in a nude mouse xenograft model. The three different formulations of MTO [free MTO, phosphatidic acid (PA)-MTO liposomes, pH-MTO liposomes] were administered intravenously (three mice per formulation and time point) at a dose of 4.7 micromol kg(-1) for free MTO, 6.1 micromol kg(-1) for PA-MTO and 4.5 micromol kg(-1) for pH-MTO. The concentrations of MTO were determined using high-performance liquid chromatography (HPLC) in blood, liver, heart, spleen and kidneys of the mice. Additionally, the toxicity and anti-tumour activity of MTO was evaluated in a xenograft model using a human LXFL 529/6 large-cell lung carcinoma. The dose administered was 90% of the maximum tolerated dose (MTD) of the corresponding formulation (8.1 micromol kg(-1) for free MTO, 12.1 micromol kg(-1) for PA-MTO and pH-MTO). The pharmacokinetic behaviour of PA-MTO in blood was faster than that of free MTO, but the cytotoxic effect was improved. In contrast, pH-MTO showed a tenfold increased area under the curve (AUC) in blood compared with free MTO, without improvement of the cytotoxic effect. This discrepancy between the pharmacokinetic and cytotoxic results could be explained by the fact that MTO in pH-MTO liposomes remains mainly in the vascular space, whereas MTO in PA-MTO liposomes is rapidly distributed into deep compartments, even more so than free MTO.     

锰氧化物锂离子筛研究进展

锰氧化物锂离子筛可以直接从盐湖卤水和海水中提取锂，是极具发展前景的锂吸附剂。文章介绍了锰氧化物锂离子筛前驱体LiMn2O4的结构，综述了国内外有关锂离子筛的反应机理研究，详述了目前其前驱体合成方法及造粒工作的研究成果，同时对锂离子筛的发展提出了自己的见解。     

Ultrafast electron diffraction and direct observation of transient structures in a chemical reaction

Ultrafast electron diffraction is a unique method for the studies of structural changes of complex molecular systems. In this contribution, we report direct ultrafast electron diffraction study of the evolution of short-lived intermediates in the course of a chemical change. Specifically, we observe the transient intermediate in the elimination reaction of 1,2-diiodotetrafluoroethane (C2F4I2) to produce the corresponding ethylene derivative by the breakage of two carbon-iodine, C---I, bonds. The evolution of the ground-state intermediate (C2F4I radical) is directly revealed in the population change of a single chemical bond, namely the second C---I bond. The elimination of two iodine atoms was shown to be nonconcerted, with reaction time of the second C---I bond breakage being 17 +/- 2 ps. The structure of the short-lived C2F4I radical is more favorable to the classical radical structure than to the bridged radical structure. This leap in our ability to record structural changes on the ps and shorter time scales bodes well for many future applications in complex molecular systems.     

柠檬酸盐溶液吸收-超声解吸净化低浓度二氧化硫

以柠檬酸盐溶液为吸收剂,旋流板式气体净化器作为吸收设备,考察了柠檬酸盐吸收净化低浓度SO2的效果,并对超声解吸再生吸收剂进行了研究。结果表明：柠檬酸盐溶液吸收SO2的效果与柠檬酸盐浓度、溶液pH值及烟气中SO2浓度有关;超声解吸SO2在超声场强300-350W/L范围内效果较佳,最大解吸率可达82%,且解吸率与柠檬酸盐浓度、吸收液初始pH值成反比。     

纳米TiO2负载钯催化剂的性能研究

采用浸渍法制备了纳米TiO2负载钯催化剂,以乙炔选择催化加氢制备乙烯为反应模型考察了稀土元素La、空速对纳米Pd／TiO2催化剂性能的影响,并与纳米SiO2为载体的Pd—La／SiO2催化剂的性能做了比较。实验结果表明,纳米Pd／TiO2催化剂具有良好的催化活性和性能稳定性,La的加入显著提高了乙烯的选择性、增幅达加％左右。与Pd—La／SiO2催化剂相比,Pd—La／TiO2催化剂具有更高的选择性。     

Relationships among absorbents on the reduction of grass silage effluent and silage quality

Effluent from grass silage is a threat to water quality and a loss of valuable forage nutrients from dairy farms. Absorbents potentially reduce effluent loss when weather conditions are not ideal for field wilting. The objective was to determine the effectiveness of various absorbents at reducing silage effluent. First-harvest, direct-cut, perennial grass forage was ensiled with and without absorbents in medium-sized experimental silos for 3 consecutive yr. Silos contained 4.54 kg of grass and one of the following feed quality absorbents: 10% rolled barley, 10% dried and pelleted beet pulp, or alfalfa cubes at 10, 20, or 30%. Nonfeed quality absorbents used were 1% starch grafter polymer, 1% bentonite clay, and 10% newspaper. Silage from direct-harvest control forage produced the highest effluent losses, but the wilting of grass prior to ensiling or the mixing of grass with 30% alfalfa cubes nearly eliminated effluent. Silage pH was lowest when rolled barley or beet pulp was used as the absorbent and was highest for wilted grass. Silage dry matter was increased by wilting and by the use of barley, beet pulp, newspapers, or alfalfa cubes as absorbents. The addition of 10% newspaper greatly reduced in vitro dry matter digestibility and crude protein. Increased water-soluble carbohydrate concentrations were found for silage from grass forage treated with rolled barley, beet pulp, or alfalfa cubes prior to ensiling. Although bentonite clay and newspapers reduced effluent losses, greater water-soluble carbohydrate losses were found for these treatments compared with the direct control. Alfalfa cubes were found to be effective absorbents and did not reduce grass silage quality.     

石墨球配碳在电炉炼钢中的应用

由于废钢资源的日益紧张，电炉炼钢生产成本持续上升。通过在料篮中装入袋装石墨球增加配碳量，充分发挥C-O反应放热，减少铁损，提高金属回收率，达到低成本炼钢的目的。     

冷轧和热轧板材成品库存一体化匹配模型与方法研究

针对现代钢铁企业在面向订单(MTO)与面向库存(MTS)混合生产组织方式下库存匹配效率较低的问题,按照一体化计划的管理思想,建立了实现库存匹配重量最大化、匹配成本最小化的冷轧、热轧成品库存一体化匹配模型,该模型为多目标0-1规划模型。结合该问题的特点,利用约束规划的变量排序、值排序以及节点互换构建了启发式算法求解该模型...     

废银催化剂的再生及回收

银作催化剂用的场合不多，主要用于乙烯氧化制环氧乙烷、甲醇氧化制甲醛及乙二醇的生产。文章着重介绍了这三种废银催化剂的再生和回收。