SBR数学模型在污水处理中的研究进展

SBR为高度非稳态的处理过程,许多学者对其生化反应机理进行了研究并提出了相应的数学模型.本文介绍了SBR数学模型在污水处理中的研究进展,指出建立适合SBR工艺设计、仿真、优化的数学模型还有待进一步的研究.     

SBR反应器的热效应研究

通过对微生物生化反应机理及SBR反应器热平衡分析,建立了啤酒废水被生物降解时所产生热量的数学模型、反应器内水体吸收太阳辐射热的数学模型、反应器器壁的热量传递数学模型、反应器水面散发热量的数学模型。应用上述模型对拉萨啤酒厂污水站SBR反应器的热平衡进行实际计算,计算所得反应器内水体温度为19.8℃,与实测结果基本吻合。该研究结果对青藏高原以及北方地区的废水治理有一定的借鉴作用。     

SBR工艺过程控制策略研究进展

将SBR过程控制策略分为定时控制、实时控制和智能控制3类,分别进行了简要的介绍,并介绍了采用新工艺机理的SBR控制技术,重点对SBR实时控制策略原理和应用进行了分析、归纳和总结.并对SBR工艺过程控制策略的未来研究方向进行了展望.     

不同门尼粘度丁苯橡胶的性能分析

分别对不同牌号相同门尼粘度的SBR和相同牌号不同门尼粘度的SBR硫化特性、加工性能和物理机械性能进行了研究.结果表明,SBR1500和SBR1712的门尼粘度相同,但两者的加工性能、硫化速度和物理机械性能却相差较大;随着门尼粘度的增大,SBR1712的拉伸强度逐渐增大,硫化速度加快.在SBR技术指标范围内,门尼粘度与加工性能的相关性并不大.     

凹凸棒土填充SBR的性能研究

试验研究不同硅烷偶联剂改性凹凸棒土(简称AT)填充SBR硫化胶的物理性能,并以结合橡胶研究补强机理.结果表明,硅烷偶联剂KH-550,KH-560和Si69能明显提高AT/SBR复合材料的物理性能,热重分析显示这些偶联剂提高了AT/SBR混炼胶的结合橡胶含量,增强了AT与SBR分子之间的相互作用;AT经偶联剂Si69改性后可以部分替代炭黑和白炭黑用于填充SBR.     

SBR法在难降解废水处理中的研究及应用

介绍了SBR法的发展过程及其在污水处理中的运行模式和优点,列举了SBR法在国内外的应用实例.根据SBR反应器自身特点,可以衍生出以SBR反应器为主的多种新工艺,如PAC-SBR、两段SBR、多段SBR和预处理SBR.实践证明,采用SBR法处理各种难降解的工业废水时,对CODCr、BOD5、氨氮、总磷和色度都有较高的去除率,处理后出水均达标排放.SBR法在处理难降解工业废水中将得到更为广泛的应用.     

高耐磨炭黑填充型粉末SBR研究Ⅰ.粉末化条件与粒径分布

用SBR胶乳、高耐磨炭黑为原料,高分子树脂为炭黑表面改性剂兼包覆剂,以凝聚共沉法制备了炭黑填充型粉末SBR;研究了粉末化条件对产物粒径分布的影响因素.结果发现,由SBR胶乳、改性炭黑和Tg为35℃的包覆剂构成的粉末化体系在85℃处理1h可形成无接触污染性的、粒径小于0.9mm的炭黑填充型粉末SBR.SEM分析表明,炭黑粒子被包埋在SBR基体中,无游离炭黑存在.     

充油丁苯橡胶SBR1721实用配方的试验研究

充油丁苯橡胶SBR1721,其丁苯基础胶的结合苯乙烯含量为40%,100份胶中填充37.5份高芳烃油。SBR1721具有优异的抗湿滑性能,同时具有良好的加工性能,是制造高性能子午线轮胎胎面胶的理想材料。近几年,随着高性能子午线轮胎生产量的提高,国外SBR1721的用量在增加。齐鲁橡胶厂经过多年研究开发,成功进行了SBR1721的工业化试生产。本工作在完成对齐鲁橡胶厂开发的SBR1721样品的基本性能和加工性能试验之后,又对其进行了轮胎胎面胶和三角胶的实用配方试验研究。一、轿车子午线轮胎胎面胶1.试验配方胎面胶试验配方为:SBR172170.0;SBR71226.…     

反相气相色谱法测定丁苯橡胶的溶解度参数

试验研究反相气相色谱法测定丁苯橡胶(SBR)的溶解度参数.结果表明:正辛烷和正壬烷是SBR的一般溶剂,三氯甲烷是SBR的良溶剂,正庚烷、正己烷、丙酮和乙酸乙酯是SBR的不良溶剂;利用相互作用参数与温度的关系,外推可得到室温时SBR的溶解度参数为17.8(J·cm-3)0.5.     

不同苯乙烯含量丁苯橡胶与天然橡胶并用的研究

将普通丁苯橡胶(SBR1,苯乙烯质量分数为0. 235)和高苯乙烯SBR(SBR2,苯乙烯质量分数为0. 68)分别与天然橡胶(NR)并用,研究NR/SBR并用比和SBR苯乙烯含量对并用胶硫化特性、物理性能和阻尼性能的影响。结果表明:随着SBR用量的增大,NR/SBR并用胶的硫化速度、拉伸强度和撕裂强度下降,NR/SBR1并用胶的滞后能量密度(HED)先增大后减小,NR/SBR2并用胶的HED增大;NR/SBR并用比相同时,NR/SBR2并用胶的硫化速度、拉伸强度、拉断伸长率和撕裂强度低于NR/SBR1并用胶;NR/SBR2并用胶的有效阻尼温域拓宽至高温区。     

生物处理液态烃等混合碱渣废水

运用间歇式活性污泥法(SBR)技术处理某炼油厂液态烃碱渣、催化汽油碱渣和丁辛醇废水构成的混合碱渣,主要考察了COD的去除效果。应用数学模型模拟SBR处理该废水的效果,并求解出了两个模型参数,然后进行了验证。模型显示,该碱渣废水中含有较高的不可生物降解物质。     

Vulcanization of rubber. Kinetic parameters for SBR and simulations of vulcanization in a mold

Differential scanning caiorimetry (DSC) was used to characterize the vulcanization of styrene-butadiene rubber (SBR). The effect of three different fillers on the vulcanization process was also investigated. The fillers used were carbon black HAF and SRF and silica. The calculated reaction orders, activation energy, reaction energy, and preexponential factor, completed with physical properties, were used to calculate the temperature and extent of reaction inside a mold with time. The mathematical model used yields that are in fair agreement with experimental temperature measurements inside the mold.     

Modeling and simulation of the formation and utilization of microbial products in aerobic granular sludge

A mathematical model is established to simulate the formation of extracellular polymeric substances (EPS), soluble microbial products (SMP), and internal storage products (X_STO) in aerobic granular sludge. The sensitivity of these microbial products concentrations toward the key model parameters is analyzed. Independent experiments are conducted to find required parameter values and to test its predictive ability. The model is evaluated by using one‐cycle operating experimental results of a lab‐scale aerobic granule‐based sequencing batch reactor (SBR) and batch experimental results. Results show that the model is able to describe the microbial product dynamics in aerobic granules and provide further insights into a granule‐based SBR. The effect of the initial substrate and biomass concentrations on the formation of microbial products in aerobic granular sludge can therefore be analyzed by model simulation. A higher substrate concentration results in a greater concentration of EPS, SMP, and X_STO. An accumulation of biomass in the bioreactor leads to an increased production rate of EPS, SMP, and X_STO. © 2009 American Institute of Chemical Engineers AIChE J, 2010     

Pyrolytic treatment of rubber waste: Pyrolysis kinetics of styrene—butadiene rubber

The pyrolysis kinetics of commercial-grade styrene–butadiene rubber (SBR), which is one of the major constituents of tyre rubber as well as one of the principal products of the rubber industry in Taiwan, was investigated by a dynamic thermogravimetry (TG) reaction system in a nitrogen atmosphere over the temperature range of 400 to 950 K at the nominal heating rates of 3, 5 and 7 K min⁻¹. The experimental results indicated that the pyrolysis of SBR may be attributed to three reactions, with three distinct mass change characteristics in the mass-loss curves of reactant deduced from the experiments. The corresponding activation energies, frequency factors and reaction orders of the three reactions were determined. A simplified three-reaction model based on the mass-loss curves of reactant was also proposed for engineering purposes. Satisfactory agreements between the proposed model and the experimental results were obtained. The results of this study are useful for the utilization of scrap SBR as an energy resource.     

STEADY-STATE MODELLING OF A LATEX REACTOR TRAIN FOR THE PRODUCTION OF STYRENE-BUTADIENE RUBBER

A mathematical model is developed for the emulsion copolymerization of styrene and butadiene carried out in a continuous train of stirred tank reactors. The model predicts copolymer composition, conversion, molecular weight averages, and long chain branching frequencies, as well as the latex particle size distribution for all reactors in the train. It is capable of simulating closely the behaviour of industrial SBR processes.

Several simulation studies are performed. Topics investigated include: process operating modifications to improve productivity; the effect of chain transfer agent flow rate and number of reactors on the molecular weight development; the effect of process modifications on the development of the particle size distribution down the reactor train; and the effect of reactor design on particle generation rates.     

Derivation of optimal operating policies under safety and technological constraints for the acetoacetylation of pyrrole in a semi-batch catalytic reactor

A large number of optimization strategies have been developed for semi-batch reactors (SBR) with a fixed or free terminal time, with or without considering various sources of uncertainty. Such strategies account for safety constraints rather empirically determined in the form of parameter thresholds, while safety indices are seldom integrated in the optimization objective function. The present work illustrates how the runaway boundaries, and their confidence region associated to the parameter uncertainty, can be evaluated using the process model and a generalized sensitivity criterion, and how they can be included in the SBR optimization. A concrete example is provided for the SBR used for the acetoacetylation of pyrrole with diketene in homogeneous catalysis, a process known to be of high risk due to the very exothermic side-reactions. While previous studies approached the isothermal SBR, the present work is focused on optimizing the non-isothermal SBR operation.     

Preparation of lignin-based filling antioxidant and its application in styrene-butadiene rubber

A novel filling antioxidant (Lig-g-RT) to improve the mechanical properties and antiaging performance of styrene-butadiene rubber (SBR) composites was prepared by grafting antioxidant intermediate p-aminodiphenylamine (RT) on the surface of lignin via the linkage of silane coupling agent. Fourier transform infrared (FTIR) and thermogravimetric analysis (TGA) measurements confirmed that RT was successfully grafted on the surface of lignin to produce the functionalized Lig-g-RT which shows a better thermal stability than lignin. Compared with SBR/lignin composite, the SBR/Lig-g-RT composite using latex co-precipitation method exhibits a much better filler dispersion, which contributes to the maintain of the physical mechanical properties of SBR vulcanizates. Moreover, the SBR/Lig-g-RT vulcanizate exhibits less chemical crosslink concentration and higher entanglement density than SBR/lignin vulcanizate according to the Mooney–Rivlin model analysis. In addition, the stabilizing effect of lignin/Lig-g-RT on the carbon-black filled SBR vulcanizates is comparable with that of commercial antioxidant N-1,3-dimethylbutyl-N′-phenyl-p-phenylenediamine (4020), especially the SBR vulcanizate filled with 10 phr Lig-g-RT obtains the optimum thermo-oxidative aging properties. This functionalized Lig-g-RT not only provides an intramolecular synergistic antiaging effect for SBR vulcanizates and an improvement of filler dispersion, but greatly extends the comprehensive utilization of industrial lignin.     

Use of natural rubber prophylactics waste as a potential filler in styrene–butadiene rubber compounds

Owing to the unstable nature of the latex compound and the strict specifications in the quality of latex products such as condoms and examination gloves, the rejection in the latex industry comes to about 10 to 15% of the rubber consumed. These latex rejects contain about 95% rubber hydrocarbon of very high quality. A cost-effective technique has been developed for the reuse of natural rubber (NR) prophylacties waste in styrene–butadiene rubber (SBR). The influence of powdered latex rejects on the curing characteristics, mechanical properties, and failure behavior of SBR has been investigated. More emphasis is placed on the effect of both particle size and the loading of latex waste filler. Swelling studies were carried out to establish the degree of crosslinking of SBR and to assess the extent of interaction between the matrix and latex waste filler of varying particle sizes. A three layer model has been set up to study the diffusion of sulfur from the matrix phase to the filler phase. Scanning electron microscopy has been used to analyze the particle morphology, filler dispersion, and filler-matrix interface adhesion. The results of the study revealed that NR prophylactics rejects can be used effectively as a potential filler in SBR up to about 40 phr loading. © 1996 John Wiley & Sons, Inc.