Removal of Cyanides from Water by Air Oxidation in a Cocurrent Downflow Fixed Bed Reactor

A method for removal of cyanides from water is described. The method involves the air oxidation of cyanides in a fixed bed reactor with cocurrent downflow. Effects of parameters such as temperature, concentration, gas and liquid flow rates on the oxidation yield are studied. It was observed that the yield increases by increasing temperature and decreasing gas and liquid flow rates. Altering the concentration had no clear effect on the yield. A yield of 86 % was achieved at high temperature (60°C) while the maximum yield was 68 % at room temperature.     

Effect of Temperature on Controlled Air Oxidation of Plastic and Biomass in a Packed‐Bed Reactor

A packed‐bed reactor was established to study the effect of temperature on the controlled air oxidation (CAO) performance of a mixture of polypropylene and sawdust at a fixed feed gas flow rate. The reactor temperature was varied from 400 to 800 °C. Attention was focused on product distribution, compositions of liquid and gas products, and technical parameters. The chemical composition of the liquid products was analyzed by gas chromatography/mass spectrometry. The results indicated an obvious impact of the temperature on the described parameters. The increase in temperature led to the decrease in solid fraction and a convex shape curve for the gas yield as well as to a decrease of alkanes and alkenes, and favored the generation of oxygen‐containing hydrocarbons. According to criteria of CAO conversion, the optimum temperature in the primary chamber was found to be 700 °C.     

对二甲苯富氧氧化的研究及工业化试验

研究了以Co-Mn-Br为催化剂,对二甲苯(PX)液相氧化下不同氧浓度(质量分数21％~31％)和不同空速对对苯二甲酸(TA)产率、中间产物含量、PX消耗速率和尾气中二氧化碳含量等的影响。结果表明:提高进气中氧浓度,尾气中氧浓度相应提高,有利于加快PX的氧化和TA的生成速率,且未加剧醋酸深度氧化生成二氧化碳。在PX处理量一定时,提高进气氧浓度可大大降低气体空速。工业化富氧(氧气质量分数23％)条件下的氧化反应安全可行,不影响产品质量。     

Experimental study on the controlled air oxidation of sawdust in a packed-bed reactor

The controlled air oxidation technology is a promising way of disposing medical waste, which has been a huge challenge in China. It converts waste through partial oxidation into a gaseous mixture, small quantities of char and condensable compounds. But operational performance of the primary chamber of the controlled air incinerator is poorly understood, leading to difficulty in control. In this paper, a packed-bed reactor was established to study the effect of O₂ concentration on sawdust oxidation. The feed gas flow rate was kept constant at 0.6 m³/h at room temperature (26 °C) with O₂ concentrations varied from 6% to 12%. Temperature profiles of the beds, product yields and gas compositions in the out-of-bed fuel gas were measured in detail. The results showed that the sawdust beds achieved low temperatures for the given O₂ concentrations and leveled off in the oxidation processes. The bed temperatures increased and the solid yields decreased with the increase of O₂ concentrations. When the O₂ concentration was 10%, the gas yield reached a minimum and the liquid reached a maximum correspondingly. When the O₂ concentration increased from 6% to 10%, the peak concentrations of CO and CH₄ in the gas yield increased. However, when the O₂ concentration exceeded 10%, CO and CH₄ concentrations decreased. As O₂ concentration varied from 6% to 12%, CO₂ concentration increased continuously. This study provides a fundamental insight that the reaction processes could be well regulated by means of adjusting the feed air in practical units.     

外环流气升式反应器中催化丙烯环氧化反应

本论文研究了外环流气升式反应器中TS-1催化丙烯环氧化反应,以单位催化剂空时收率为目标,进行了反应工艺条件的优化,考察了结构参数,上升管与下降管横截面积之比Ar Ad对反应的影响。     

卷式纳滤膜的气液两相流清洗特性

引言 膜分离技术在化工、食品、医药、石油、环境等领域已有广泛应用.其中卷式纳滤膜因装填密度大、膜元件更换方便、适用面广等优点,在各行业已大规模进人工业应用,但膜污染问题是制约其发展的主要因素.工业上通常采用化学清洗方法,但清洗时间长,清洗用水和清洗剂消耗量大,同时产生大量清洗废水,且难以保证清洗效果.     

稀土偶联剂（REC）对PP／Mg（OH）2体系性能的影响

研究了稀土偶联剂（ＲＥＣ）处理对ＰＰ／氢氧化镁（Ｍｇ（ＯＨ）２）体系的燃烧性能、流动性能、力学性能及老化性能的影响。未经处理的Ｍｇ（ＯＨ）２在填充量超过５０％时,ＰＰ／Ｍｇ（ＯＨ）２体系的ＯＩ≥２８．５,但这时冲击强度不足纯ＰＰ的３０％,熔体流动速率低于０．６ｇ／１０ｍｉｎ;而填料用２．５％（重量）ＲＥＣ处理后,填充量为５０％的体系冲击强度接近纯ＰＰ,ＭＦＲ达２．８ｇ／１０ｍｉｎ;ＲＥＣ对Ｍｇ（Ｏ     

甲苯液相氧化反应过程的模拟

甲苯液相空气氧化是环境友好的苯甲酸和苯甲醛生产工艺。根据在模拟工业条件下测定的动力学数据和观察到的实验现象,提出了该反应的反应机理和反应网络,建立了相应的动力学模型。根据该动力学方程,对现有工业生产过程进行了模拟,发现现有工业过程处于严重供氧不足的情况。提出了3种强化方案并分别对其进行了模拟计算和比较。模拟结果表明,通过增大空气供给量和采用富氧空气氧化均可有效强化现有工业生产过程。采用富氧空气氧化,其甲苯转化率可提高到22.24%,甲苯反应量可增大57%。采用增大空气量的方法,可提高甲苯反应量31%,甲苯转化率可提高到18.61%。若同时增大甲苯和空气负荷,甲苯反应量可提高71%。     

污泥低温热处理过程研究

研究了脱水干燥污泥在管式炉中不同条件下的热处理行为。主要考察了热处理气氛(空气、氮气)、时间、温度、气体流量等对污泥热处理行为的影响。结果表明,在空气气氛(20 mL/min)、440℃、热处理50 min时液体收率最高,为42.5%,固体和气体分别为49.5%和8.0%。     

Distribution performance of gas-liquid mixture in the shell side of spiral-wound heat exchangers

The non-uniformity of gas-liquid mixture is a critical issue which leads to the heat transfer deterioration of spiralwound heat exchangers (SWHEs). Two-phase mass flow rate and the content of gas are important parameters as well as structural parameters which have prominent influences on flow distribution uniformity of SWHE shell side. In order to investigate the influences of these parameters, an experimental test system was built using water and air as mediums and a novel distributor named "tubes distributor" was designed. The effects of mass flow rate and the content of gas on two-phase distribution performance were analyzed, where the mass flow rate ranged from 28.4 to 171.9 kg·h^-1 and the content of gas changed from 0.2 to 0.8, respectively. The results showed that the mixture mass flow rate considerably influenced the liquid distribution than that of gas phase and the larger mass flow rate exhibited the better distribution uniformity of two-phase flow. It was also found that the tubes distributor had the better two-phase uniformity when the content of gas was around 0.4. Tube diameter played an important role in the distribution of gas phase and slit width was more significant for the uniformity of liquid phase.     

Air oxidation of aqueous cyanides in a countercurrent fixed bed reactor

This study was conducted to discuss the removal of cyanides from water by air oxidation. Experiments were carried out in a countercurrent fixed bed reactor for three different values of temperature, concentration, gas and liquid flow rates. It was operated at pH 12 by using delrin (formaldehyde polymer) as packing material. Effects of some operating parameters on the conversion were studied, and it was observed that the conversion percent increased by increasing temperature and decreasing gas and liquid flow rates. Effect of concentration was not steady. A conversion of 89% was achieved under optimum conditions while it ranges from 44 to 79% at room temperature.     

芳烃抽余油磺化工艺的研究

以气相三氧化硫为磺化剂,芳烃抽余油为原料,通过气体SO3和芳烃抽余油液膜进行连续的管式气-液反应,考察了SO3气体流量、夹套的水温、进料温度和流量对抽余油磺化收率的影响.实验结果表明,SO3气相膜式磺化反应的条件为：抽余油的进料流量为77 g/min,进料温度为30℃、SO3气体流量为2.5 L/min、干燥空气流量为l00 L/min、改变夹套水温35℃时,抽余油磺化产率最高,最高产率为52.7％.     

聚丙烯抗冲共聚物的制备技术

在中试产品开发的基础上聚合理论分别从催化剂的选择、预聚合工艺、共聚釜气相乙烯浓度、乙烯加入量、均聚合量、共聚合量、各釜熔体流动速度、粉末输送性能等方面阐述了聚丙烯抗冲共聚物（ＩＣＰ）的制备技术。结果认为柔聚合条件加科次序十分重要,要选用活 生寿命长、空隙率高的催化剂、并严格控制气相乙烯浓度。     

臭氧氧化处理法对聚丙烯表面涂装性的改良 Ⅱ.臭氧浓度及臭氧发生气组成对聚丙烯表面氧化过程的影响

讨论了用臭氧氧化法对聚丙烯表面进行涂装性改良时,臭氧浓度和臭氧发生气组成对聚丙烯表面氧化过程的影响。我们发现,随臭氧浓度的增加,各种聚丙烯表面上COOH基的生成速率变大,而OH基的生成速率变小,且表面上COOH基和OH基的生成比变大。在相同的臭氧浓度下,COOH基的生成速率和聚丙烯种类无关,各种聚丙烯表面上COOH的生成速率大体相等。而OH基的生成速率及COOH基、OH基生成比和聚丙烯的种类有关,就COOH基和OH基生成比而言,其大小顺序为均聚物>嵌段共聚物>无规共聚物。臭氧发生气组成对聚丙烯表面氧化过程有很大的影响。和臭氧发生气为空气时的情况相比,当臭氧发生气为氧气时,即使其体系中臭氧浓度的变化很小,也会引起较大的表面氧吸收量或表面氧化分解量的变化。     

Pyrolysis of oil sand from the Whiterocks deposit in a rotary kiln

A rotary kiln reactor was evaluated for thermal recovery of oil from Utah oil sands. A series of continuous-flow pyrolysis experiments was conducted. Process variables investigated included temperature (748–848 K), solids retention time (10–27 min) and sweep gas flow rate (1.27–2.83 m_s³ h⁻¹). The results indicated that the pyrolysis temperature and the solids retention time were the two most important variables affecting the liquid and gas yields. The liquid yield (C₅⁺]) decreased and the gas yield (C₁–C₄) increased with increasing temperature. The liquid yield increased with decreasing solids retention time, while the gas yield decreased. No significant effect of the sweep gas flow rate on the product distribution and yields was observed. The quality of the bitumen-derived liquids was significantly better than that of the bitumen. A preliminary process kinetics model which conforms to the observed trends was proposed.     

陶瓷膜接触器化学吸收氮氧化物的传质过程与阻力分析

针对选择性催化还原技术(SCR)存在装置大、运行费用高、催化剂中毒失活等问题,将平均孔径为100 nm的Al₂O₃陶瓷膜进行疏水改性并组装成膜接触器,以NaClO₂水溶液为吸收液,开展陶瓷膜接触器在烟气脱硝领域的应用研究。考察了陶瓷膜接触器在化学吸收脱硝中的稳定性,以及气体流量、吸收液浓度、吸收液流量、吸收液pH等因素对NO脱除率和传质通量的影响,基于阻力串联模型,建立总传质系数方程。研究表明,陶瓷膜接触器在连续600 min运行过程中,NO的脱除效率及传质通量分别稳定在99%和0.038 mol·m^-2·h^-1左右。进气流量的增加会促进NO的吸收,吸收液pH=3时具有最高的氧化吸收性能,同时提高吸收液的浓度会增强NO的脱除效果。NO的传质过程同时受气、液、膜三相阻力控制,传质阻力分析结果表明,可以通过增加气体流速减小气相阻力,增加吸收液浓度同时降低pH减小液相阻力。本研究在烟气脱硝领域具有良好的应用前景。     

流化床串联多段冷激式绝热固定床HCl氧化反应模拟优化

提出了由流化床与多段冷激式绝热固定床串联的新型HCl氧化制氯反应工艺. 通过物料、能量、动量衡算建立了绝热反应器一维数学模型,对绝热固定床反应器段间冷激气种类、流率、流化床反应器进口处HCl与O2摩尔配比及催化剂用量等工艺参数进行了优化计算. 结果表明,液态氧为较适宜的冷激气,流化床反应器入口处最佳HCl与O2摩尔配比为1:0.7,流化床和绝热床中最佳催化剂用量分别为4.3与8.6 t,在该条件下,HCl转化率可达85%.     

IDA路线草甘膦的清洁生产方法和绿色化学合成技术

以二乙醇胺为起始原料,在Cu/Zr催化剂存在下,与氢氧化钠脱氢(氧化)反应生成的亚氨基二乙酸(IDA)二钠盐收率达95%;采用固体IDA法生产双甘膦,反应收率高达97%;双甘膦氧化采用空气(含氧气体)氧化法制备草甘膦,反应收率达95%,草甘膦原药含量达97%以上。并通过采用膜分离技术提浓草甘膦母液、回收脱氢反应废气中的氢气制备双氧水、改进双甘膦制备过程废水和废渣的回收利用,使IDA路线草甘膦生产工艺基本实现了安全、节能、环保和资源充分利用的清洁生产和循环经济,并提高了产品质量,降低了生产成本。     

垂直管中零净液流量气液两相流的持液率研究

Zero net-liquid flow (ZNLF) is a special case of upward gas-liquid two-phase flow. It is a phenomenon observed as a gas-liquid mixture flows in a conduit but the net liquid flow rate is zero. Investigation on the liquid holdup of ZNLF is conducted in a vertical ten-meter tube with diameter of 76 mm, both for Newtonian and nonNewtonian fluids. The gas phase is air. The Newtonian fluid is water and the non-Newtonian fluids are water-based guar gel solutions. The correlations developed for predicting liquid holdup on the basis of Lockhart-Martinelli parameter are not suitable to ZNLF. A constitutive correlation for the liquid holdup of vertical ZNLF was put forward by using the mass balance. It is found that the liquid holdup in ZNLF is dependent on both the gas flow rate and the flow distribution coefficient.     

Effect of branching of polyolefin backbone chain on catalytic gasification reaction

A basic study on the catalytic gasification of polyolefins such as PE and PP, which account for a major part of general waste plastics, was conducted in order to develop a technique for effective recycling of these wastes. In the case of PE, the gasification of PE is considered to consist of the following scheme: polymer → catalytically degraded polymer → catalytically degraded oligomer → liquid component → gas component. The gasification of PE does not occur directly from the polymer chains, but gaseous C₄ substances are selectively found from the liquid components with the highest branching frequency. The overall yield of C₄ components including isobutane was 74.5 and 60.5% molar for PE and PP. These liquid components (gasification precursors) have the branching frequencies. For example, a molecule with M?_w of 400 contains about eight branches for every 30 methylenes. From the catalytic gasification of PE, PP, and PIB, the gas conversion rate is also found to increase with increasing frequency of the backbone branching. It is concluded that the branching frequency is the key factor governing the gas conversion rate of polyolefins.