Modeling simultaneous biological clogging and physical plugging in trickle-bed bioreactors for wastewater treatment

A major drawback limiting the use of trickle-bed bioreactors for biological wastewater treatment is ascribed to the concomitant biological clogging and physical plugging phenomena induced, respectively, by the formation of an excessive amount of biomass and the retention of inert suspended fine particles advected in the liquid influent stream. Biomass growth and fine particles deposition permanently reshape the bed pore structure and narrow the free interstitial space left to the fluids flow thus occasioning progressive bed obstruction often accompanied with pressure drop build-up for the cocurrent gas-liquid flows taking place in trickle-bed biofilters. In these circumstances, for maintaining acceptable operating cycles, the unit must be backwashed and/or shutdown regularly for removing the excess biomass and for cleaning from the specific solid deposit. A predictive two-dimensional dynamic model linking the two-phase flow hydrodynamics to the space-time distribution of bioclogging/biokinetics and of inert fine particles deposition via deep-bed filtration in trickle-bed bioreactors for wastewater treatment was developed. The model was based on the volume-average mass and momentum balance equations for the gas and liquid phases and continuity equation for the solid phase, the volume-average species balance for the fine particles, simultaneous transport and consumption of substrate (pollutant) and oxygen within the biofilm and collecting solid particle, and the volume-average species balance equations in the liquid and gas phases. Phenol biodegradation by Pseudomonas putida as the predominant species immobilized on activated carbon was chosen as a case study to illustrate the incidence of biomass accumulation on trickle-bed bioreactor hydrodynamics.     

地面集输管线中水合物堵塞预测研究

天然气水合物一旦在地面集输管线中形成就会造成阀门堵塞、管道停输等严重事故,造成重大的经济损失。气流组成、温度、压力和含水量是影响地面集输管线中水合物形成的主要因素,此外,气井产量、管线长度、油管直径等对水合物的形成也有一定的影响。本文综合国内外有关水合物研究成果,并结合长庆气田某气藏生产过程中天然气水合物的生成条件及防治措施,对地面集输管线中天然气水合物堵塞的生成条件及预测模型进行了研究。     

聚合物冻胶类堵剂在油田堵水中的应用

在油田堵水作业中聚合物类堵剂得到了广泛的应用,美国FOR方案设计中有35％采用聚合物,而其中的60％采用的是冻胶处理;在国内,聚合物冻胶类堵剂在油田八大类堵水体系中也占有较大的比例。文章描述了聚合物冻胶类堵剂在国内外的发展现状,根据聚合物类型的不同对该类冻胶进行分类,并介绍了其作用机理、应用情况、施工工艺以及理论研究情况,其中PI决策技术已经被广泛地用于指导油田调剖作业,最后指出针对深层、高温油藏聚合物冻胶类堵剂仍有广阔的发展前景。     

Catalyst pore plugging effects on hydrocracking reactions in an Ebullated bed reactor operation

This paper analyzes the deactivation effects of NiMo/Al₂O₃ catalyst during the operation in an Ebullated bed reactor for Heavy residue hydrocracking. The spent catalysts were characterized by chemical analysis, ¹³C NMR, ESM, DRX, and by using thermal programmed oxidation and diffusion studies in a shallow bed micro-reactor. The deactivations were performed in a 5 l continuously stirred tank reactor, while the spent catalysts were tested in a 0.05 l micro-reactor. The study focused on determining the properties of the external layer of the catalyst and on evaluating the internal coke and metal deposition. The results indicated that initial deactivation is mainly due to coke depositions, while its impact on mass transfer reaction control depends on temperature. In long-term deactivation, the metal deposition plays a more important role in blocking the internal micro- and meso-structures and in building up the external layer of the pellets.     

渤海注聚井区油井深部解堵工艺研究及应用

针对渤海油田油井解堵效果变差、有效期降低等问题,提出了扩大解堵半径、优选解堵剂体系、强化解堵效果的解堵思路。通过工艺研究、工艺优选,形成了深穿透解堵技术。深穿透解堵技术主要包含基质解堵、降阻造缝和储层深部解堵三个过程。对深穿透解堵工艺机理进行了研究,并形成了一套现场可应用的工艺技术。针对锦州油田注聚井区堵塞问题,从聚合物溶液降黏、模拟含聚堵塞物、现场含聚堵塞物降解三个方面优选出一种复合解堵剂,结合工艺思路形成施工方案,并进行现场应用,取得了较好的增液、增油效果。     

聚合物凝胶堵漏剂的研究与应用进展

聚合物凝胶堵漏剂是近年来逐步完善和发展起来的一种堵漏材料。简要介绍了聚合物凝胶堵漏剂特点及作用机理,并对国内外聚合物凝胶堵漏剂的研究及应用进行了评述。聚合物凝胶堵漏剂包括地下交联聚合物凝胶和可吸水膨胀交联聚合物凝胶,交联聚合物凝胶强度较低,必须与其他刚性材料配合才能很好地发挥作用。在堵漏施工中,交联聚合物凝胶不受漏失通道的限制,能够通过挤压变形进入裂缝和孔洞空间,最终达到封堵漏层的目的。现场应用表明,聚合物凝胶堵漏剂与其他材料配合使用,能很好地解决钻井过程中的恶性漏失,堵漏成功率高,对碳酸盐岩、裂缝发育地层及孔洞漏失特别有效。     

超稠油综合解堵增产技术

随着超稠油吞吐轮次的增加,原油中的重质成分沉积以及无机垢的形成,岩石的润湿反转,以及水锁、粘土膨胀等因素致使近井地带污染越来越严重,加上地层压力低,造成油井周期生产时间缩短,周期产油减少,低产甚至不出。本技术既能解除近井地带的无机、有机物堵塞,恢复措施井的地层渗透率,同时在注汽过程中产生大量气体和具有表面活性的物质,能够有效地改变岩石的润湿性,降低原油的粘度,增加地层的返排能力,从而提高蒸汽吞吐效果。措施后注汽压力降低,满足现场注汽要求,增油效果明显,取得良好的措施效果。     

JHXD油溶性聚合物选堵剂的研究

针对注水开发油田选择性堵水的急需,研制了一类新型油溶性聚合物选堵剂JHXD。试验结果表明：JHXD具有良好的油溶性,其堵水率大于99％,而堵油率仅为10％左右,是一类优良的选择性堵水剂。     

C_5-MSV柴油降凝剂的研究

采用与马来酸酐接枝的方法对C5石油树脂进行改性,接枝物与苯乙烯、醋酸乙烯酯共聚,用高碳醇进行醇解,研制出一种新型柴油降凝剂。考察了C5石油树脂与马来酸酐的质量比、苯乙烯和醋酸乙烯酯的用量、引发剂用量以及反应时间、反应温度对降凝剂效果的影响。结果表明,最佳反应条件是：C5石油树脂∶马来酸酐=10∶1.2（质量比）,过氧化苯甲酰0.1 g,苯乙烯1.30 g,醋酸乙烯酯1.60 g。此降凝剂用于抚顺石化0#柴油馏分,可降低其冷滤点5℃。     

暂堵酸化技术在杜16块杜家台油藏的应用

针对杜16块杜家台油层纵向渗透率差异较大,部分井各层发育不明显,不具备工具卡封条件的具体状况,研制了新型的暂堵剂,对高渗透层具有暂时封堵,又能在生产过程中自己解除.通过暂堵与解堵相结合,实现对高渗层的暂时封堵,对低渗透层的油层改造一次完成.现场试验见到良好的措施效果,具有广阔的推广前景.