己内酰胺装置重排反应热的回收利用

阐述了在己内酰胺装置工艺设计中,将重排反应释放出的热量用于装置内苯蒸馏及苯残液蒸馏系统的热源进行回收利用,重点对该回收利用方案设计作详细介绍。此工艺的改进,既节省了蒸馏系统所需的蒸汽,又节省了反应热移走所需的循环冷却水,从而达到节能降耗的目的。该优化工艺在己内酰胺行业具有很好的推广应用价值。     

己内酰胺装置重排反应热的回收利用

本文阐述了在己内酰胺装置工艺设计中,将重排反应释放出的热量用于装置内苯蒸馏及苯残液蒸馏系统的热源进行回收利用,本文重点对该回收利用方案设计作详细介绍。此工艺的改进,既节省了馏蒸系统所需的蒸汽,又节省了反应热移走所需的循环冷却水,从而达到节能降耗的目的。该优化工艺在己内酰胺行业具有很好的推广应用价值。     

经济的硫酸余热回收系统

<正> 硫酸生产工艺涉及释放大量热量的化学反应。硫酸制造工序包括硫磺燃烧、SO_2氧化、SO_3和水反应,以及H_2SO_4稀释、工艺过程必须取热,然而,有效地回收反应热与工艺经济性和适用性相关。孟山都环境化学公司开发了称为HRS 的余热回收系统,使硫酸装置可增加热能回收。七十年代初,典型的硫酸燃烧法硫酸装置可回收约55%的反应热能,用于发汽驱动透平和用于工艺加热。约40%反应热在酸冷却器中散失于冷却水中,另外5%为辐射热损失和物流带走热量。     

怎样拟定最佳热量回收方案

<正> 随着能源价格的不断上涨,如何充分利用余热在经济上显得愈益重要。怎样拟定最佳热量回收方案,即从工艺过程的什么部位回收热量,而这些热量又用在何处最合适,这就需要有一种方法来分析工艺过程和非工艺性热量供求情况。通常在考察某工艺过程如何最充分地实现热量回收时,往往由于没有事先确定可能回收的热量而煞费心机地研讨繁杂的换热系统。     

生产丙烯酸酯的方法

一种生产丙烯酸酯的方法，该方法是通过将丙烯和／或丙烯醛催化氧化得到的反应气体流出物部分冷凝来回收浓缩丙烯酸的粗液流，并将回收的浓缩丙烯酸的粗液流催化酯化来生产丙烯酸酯。部分冷凝允许大量挥发性醛和水与未冷凝的丙烯酸蒸汽和未冷凝反应气体中的残余物一道通过第一级回收进入第二级普通回收。(美国)     

含氨工艺冷凝液和脱碳废水低压汽提回收工艺及应用

为确保总排污水在２０００年达标排放,对汽提装置相继进行两次改造,增设脱碳废水回收系统,将脱碳废水送往Ｃ９２０１汽提回收。实现了工艺冷凝液和脱碳废水中的水和氨的回收,并增加了热量的回收,经济效益显著。     

中低温热解煤气热量清洁利用技术途径分析与策略建议

高温含焦油热解煤气携带大量显热与潜热,该部分热量高效回收利用对于整个工艺系统能效提升至关重要。为促进中低温热解过程余热资源高效回收利用,分析了激冷工艺、废热锅炉余热利用等中低温热解煤气冷却与余热利用方式的主要技术特点及不足;阐述了初冷器上段余热回收、循环氨水余热回收、上升管余热回收等高温热解煤气热量利用技术现状与特点。分析了含焦油高温热解煤气冷凝过程中焦油黏附问题、低温低压煤气热量捕捉与高效利用等中低温热解煤气热量回收利用过程中的主要技术难点。基于该技术难点及前期相变换热技术研究积累,以含焦油热解煤气冷凝-传热特性为科学基础,提出了热解煤气分级冷凝与相变换热相耦合的能量梯级回收利用一体化技术。即以焦油蒸汽不同组分露点差异与析出特性为基础,形成基于温度梯度的热解煤气分级冷凝工艺技术,逐级回收热解煤气所含热量,并实现不同馏程焦油产物在线分质回收;同时耦合复合相变换热技术,换热介质与热解煤气分级逆流换热,针对性回收热解煤气显热及低品位热解煤气潜热,实现含油热解煤气分级冷凝与热量梯级回收利用一体化,从而达到热解系统热效率与产品品质提升的双重效果。以100万t/a流化床热解工艺为例,提出了中低温热解煤气热量回收技术路线并进行了热量衡算。结果表明:该技术路线中低温热解煤气热量利用率可达到81. 17%,初步显示了其可行性。高效回收利用热解过程中的余热资源将是资源节约、环境友好热解产业发展的主要方向和潜力所在。     

基于平衡理念的二甲基二氯硅烷水解工艺

介绍了基于平衡理念的二甲基二氯硅烷（以下简称二甲）的饱和酸水解工艺,研究了系统的反应平衡、氯元素平衡、水平衡、热量平衡等,反应生成的氯化氢全部以气态形式回收,回收率达98%～99%,系统无废酸产生;制得的合格水解物收率在98%以上,基本无硅氧烷带出。     

甲醛生产过程热能优化的清洁生产改进

以三环节能量结构模型为指导,分析了甲醇氧化制甲醛工艺的特点,指出该反应气热量的回收利用是甲醛装置节能的关键所在,提出通过采用强化设备或者多段式吸收工艺的方法,将甲醛装置低温余热纳入全厂范围综合考虑,节能效果将很显著.     

丙烯酸废水处理的综合工艺

研究了丙烯酸废水中乙酸回收的工艺过程。通过电渗析技术将外排废水达到安全排放标准,同时将丙烯酸废水中乙酸浓度由2.85%提高到15%,再经过萃取、精馏富集乙酸的过程得到工业一级乙酸。此废水处理工艺改进了现有丙烯酸废水处理方法能耗高、经济性差的弊端,提高了企业经济效益,对丙烯酸产业的可持续发展具有重要意义     

Influence of microwave heating on the kinetic of acrylic acid polymerization and crosslinking

Kinetics of isothermal formation of poly (acrylic acid) (PAA) hydrogels through polymerization of acrylic acid and crosslinking of the PAA formed in a conventionally heated reaction system and in a microwave heated reaction system were investigated. It was found that in the microwave heated system the reaction rate constant of PAA hydrogel formation significantly increased (from 32 to 43 times) when compared with the conventionally heated system. The isothermal kinetics of the PAA hydrogel formation during the microwave process could be described by the so‐called first‐order chemical reaction kinetics model. In contrast, the so‐called second‐order chemical reaction rate model could best describe the isothermal kinetics of the PAA hydrogel formation during the conventionally heated process. Also, in the microwave heated system, the reaction kinetics of the PAA hydrogel formation and its kinetic parameters changed, that is, the activation energy (E_a) decreased by about 19% and the pre‐exponential factor (lnA) decreased by 2.2 times. The decrease in activation energy, change in entropy of activation energy, and decrease in the pre‐exponential value of PAA hydrogel formation under microwave heating are caused with increased energy of the reactive species when compared with their energy in thermal activation. Increased energy of the reactive species is a consequence of rapid transfer and absorption of the energy of microwave field to the existing reactive species. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

正交实验优化低分子质量聚丙烯酸钠合成工艺

采用水溶液聚合法,以丙烯酸为单体,过硫酸铵-亚硫酸氢钠为氧化还原引发体系,亚硫酸氢钠为链转移剂制得分子质量为3000～4000的聚丙烯酸钠。采用粘度法测得产物的黏均分子质量,对丙烯酸单体和聚丙烯酸钠聚合物的FTIR图谱进行了分析,通过正交实验研究了各因素对聚丙烯酸钠分子质量的影响趋势和程度。结果表明:影响最显著的因素为单体浓度,其次为反应温度,再次为引发剂用量,反应时间的影响最小。确定了最佳合成工艺条件:反应温度为45℃,反应时间为4h;丙烯酸单体质量分数为25%,引发剂过硫酸铵用量为单体质量的6%,链转移剂亚硫酸氢钠用量为单体质量的3%。FTIR谱图中不含碳碳双键,且有羧酸盐的特征峰出现,验证了聚合物的合成。该工艺节省能源,且制备方法简单,易于工业化生产。     

丙烯酸工艺技术路线分析以及直氧法探究

丙烯酸广泛用于化工行业酯类聚合单体等原料.丙烯酸作为乙烯类单体在聚合反应中聚合速率较快,它的生产工艺方法很多,主要采用甘油等原料,生产工艺方法主要有丙烷脱氢氧化以及丙烯直接氧化两种工艺方法.本文通过对比不同的生产工艺路线,依据丙烯酸生产的现状、各主要企业的产能、装置运行情况,提出了直氧法生产丙烯酸的工艺现状以及改进,提...     

乙氧基化三羟甲基丙烷三丙烯酸酯合成工艺

以甲烷磺酸为催化剂,对苯二酚为阻聚剂,用乙氧基化三羟甲基丙烷和丙烯酸在溶剂中直接发生酯化反应,再经过中和、洗涤、活性碳脱色和真空脱水,制得了乙氧基化三羟甲基丙烷三丙烯酸酯（EO3-TMPTA）。酯化率达96％以上,产品纯度达到98％,反应时间缩短到5h,该工艺有高效,节能等优点。     

Thermal and Phase Change Material Properties of Comb-Like Polyacrylic Acid-Grafted-Fatty Alcohols

Poly(acrylic acid)-graft-fatty alcohol are synthesized from the esterification of polyacrylic acid with octadecanol and docosanol. The characterization of poly(acrylic acid)-graft-fatty alcohol was performed by attenuated total reflection–Fourier transform infrared spectroscopy. The thermal stability performances and phase change behaviors of poly(acrylic acid)-graft-fatty alcohol were examined by using thermogravimetric analysis system and differential scanning calorimetry. The results indicate that the poly(acrylic acid)-graft-fatty alcohol polymeric phase change materials possess good phase change properties and provide a suitable working temperature range. The heating process phase change enthalpy is measured between 112 and 122?J g^?1, and the freezing process phase change enthalpy is found between 118 and 126?J g^?1. The decomposition of poly(acrylic acid)-graft-fatty alcohol polymeric phase change materials started at 177°C and reached a maximum of 380°C. All of the obtained poly(acrylic acid)-graft-fatty alcohol polymeric phase change materials improved latent heat storage capacity in comparison with the pristine poly(acrylic acid) polymer. With the obtained results we conclude that, these materials promise a great potential in thermal energy storage applications.     

Concentration of mixed acid by electrodialysis for the intensification of absorption process in acrylic acid production

The absorption process in acrylic acid production was water-intensive. The concentration of acrylic acid before distillation process was low, which induced to large amount of wastewater and enormous energy consumption.In this work, a new method was proposed to concentrate the side stream of absorption column and thus increase the concentration in bottom product by electrodialysis. The influence of operating conditions on concentration rate and specific energy consumption were investigated by a laboratory-scale device. When the voltage drop was 1 V·cP~(-1)(1 cP=10~(-3) Pa·s), flow velocity was 3 cm·s~(-1) and the temperature was 35 °C, the concentration rates of acrylic acid and acetic acid could be 203.3% and 156.6% in the continual-ED process. Based on the experimental data, the absorption process combined with ED was simulated, in which the diluted solution from ED process was used as spray water and the concentrated solution was feed back to the absorption column. The results shown that the flow rate of spray water was decreased by 37.1%, and the acrylic acid concentration at the bottom of the tower was increased by 4.56%. The ions exchange membranes before and after use 1200 h were tested by membrane surface morphology(scanning electron microscope), membrane chemical groups(infrared spectra), ion exchange capacity, and membrane area resistance, which indicated the membrane were stable in the acid system. This method provides new method for energy conservation and emission reduction in the traditional chemical industry.     

新型低膦水质稳定剂的研制及应用(Ⅱ)--TJ-101的合成与阻垢性能研究

以马来酸酐和丙烯酸为主要原料,加入特定添加剂,合成了一种含马来酸基、丙烯酸基、氧乙烯基、磺酸基等多元共聚物阻垢剂ＴＪ—１０１。讨论了单体配比、添加剂Ａ、Ｂ的投加、引发剂的用量、反应温度等条件对产物阻垢性能的影响,确定了ＴＪ—１０１的合成工艺,并对其阻垢性能进行了测定和比较。     

Economic trade-offs in acrylic acid reactor design

The acrylic acid process using air oxidation of propylene presents many interesting design trade-offs, particularly in the design of the reactor. The desired and undesired reactions are highly exothermic and very temperature dependent (large activation energies), so a large flowrate of inert water is also fed to the reactor to act as a thermal sink. Propylene conversion increases with temperature and reactor size, but acrylic acid yield decreases with increasing temperature. The heat of reaction is removed by generaing steam, and the steam pressure is an important design optimization variable since it sets low limits on reactor temperature. Using low-pressure steam gives high acrylic acid yield and lower carbon dioxide generation but requires large reactors. Larger air flowrates increase reactor oxygen concentrations, which reduce reactor volume but increase air compression costs.This paper explores the effects of the many design trade-offs on capital investment, energy cost and product selectivity.     

Vapour phase oxidation of acrolein to acrylic acid on mixed oxides as catalyst

The vapour phase oxidation of propylene to acrylic acid is generally carried out by a two step process, involving acrolein as an intermediate. In this work, the kinetic data on the second step of the process, i.e. the oxidation of acrolein to acrylic acid were obtained using a catalyst containing oxides of antimony, nickel and molybdenum. The effects of temperature, space time and concentration of acrolein and oxygen on the yield and conversion to acrylic acid were studied, and the most suitable conditions were determined for the process. Carbon dioxide was the major by product in the reaction. The formation of acrylic acid and carbon dioxide were correlated by suitable rate expressions.     

丙烯酸及酯聚合活性及阻聚措施的分析

烯烃类单体由于含有不饱和键,所以活性较高,容易发生自聚。本文分析了丙烯酸及酯的聚合活性,并对其阻聚进行了分析。结果表明,几种常用丙烯酸及酯产品的聚合活性如下:丙烯酸>丙烯酸甲酯>丙烯酸乙酯>丙烯酸丁酯>丙烯酸异辛酯;丙烯酸及酯常用阻聚剂的阻聚机理是富电子基团对缺电子丙烯酸及酯自由基的亲核反应。