一种新型双内循环厌氧反应器的工艺探讨

本文介绍一种新型双内循环厌氧反应器,是为了解决传统的内循环厌氧反应器由于进水水质水量的不稳定导致内循环系统的相对不稳定,且操作性较差等问题而提出的一种改进型反应器,它保留了集气室、三相分离器等设施,在此基础之上再增加一套内循环系统,包括出水集水槽、循环管道、循环水泵和循环水布水器等。改进后,新型双内循环厌氧反应器的内循环系统稳定性大大提高,新增的循环系统可进水水质的变化调整内回流比,同时可针对反应器内部不同位置进行内回流,大大增加了其操作性,即使在没有进水的情况下依然可以进行内部循环,保持厌氧污泥的活性,防止因反应器底部沉积堵塞布水器和回流管以及污泥膨胀导致的污泥流失,延长反应器的使用寿命。     

气液固三相浆态床反应器研究进展

由于在甲醇合成、费托合成等工艺中的成功应用,气液固三相浆态床反应器的研究引起了越来越多的重视.本文综述了有关浆态床反应器方面的研究,包括:流体力学性能、反应器设计、固液分离以及产业化进程.详细地介绍了影响浆态床反应器流体力学性能的主要因素:压力、温度、气体表观气速、液体性质及固含率等对流型、气含率、气泡停留时间分布和传质系数的影响.总结了近年来在浆态床反应器设计和固液分离方面的研究成果.     

基于fluent软件的布水器流态模拟

通过计算流体力学Fluent软件,对布水器流态进行了数值模拟。结果表明:在Re=19900时,绝对死区为0.0185,相对死区为0.0494m3,总死区比率高达43.3%;单纯采用操作优化或设计优化均可减小布水器死区,其优化幅度大致为38.0%左右,若采用操作和设计协同优化,可使死区降幅高达62.3%。设计布水器时,还应重点考虑近壁区布水孔的设计。     

煤间接液化费托合成浆态床反应器的研究进展

随着煤炭间接液化技术在百万吨级商业示范装置上的成功应用，作为其核心设备的费托合成浆态床反应器，涉及气液固三相湍流流动、传热传质及反应，其随反应器直径放大及内构件结构布局的变化而发生改变，进而影响反应器性能的多个复杂过程，导致在反应器设计、放大及操作优化上面临巨大挑战，科研及工业界仍然持续重视。本综述分析了影响浆态床反应器流体力学性能的主要因素，对浆态床反应器的流型、气含率、气泡行为、传热等研究进行了总结。介绍了浆态床反应器核心内构件的结构特点及发展状况，回顾了浆态床在费托合成反应过程中的工业应用历程，并展望了费托合成浆态床的研究趋势。     

鼓泡床反应器多相流CFD建模及流场研究

减压渣油的转化需要高效率的鼓泡床反应器形式;但高温高压工况特点使实验手段难以对反应器内的流场-反应耦合作用进行考察。本研究基于欧拉法建立了多相流鼓泡床反应器的反应CFD模型。通过结合渣油临氢热裂化反应动力学模型,系统考察了鼓泡床反应器内的流场特点、相含率分布、速度分布和流场-反应耦合特性,为渣油转化工艺中反应器考察和反应器设计提供了有效的理论工具。     

气相聚丙烯反应器的研究进展

聚丙烯气相法工艺具有流程简单、操作简便、装置安全性好等优点,是当前聚丙烯工业中应用最为广泛和最有发展潜力的工艺。气相聚合反应器主要包括流化床反应器、立式搅拌床反应器和卧式搅拌床反应器三种形式。本文调研了气相聚合反应器的实验和模拟的研究现状及进展,以期能够为聚丙烯反应器的设计与优化提供理论指导。     

移动床生物膜反应器在化工园区污水处理中的应用

移动床生物膜反应器工艺具有良好的抗水质水力冲击的能力,因而在化工园区污水处理中得到广泛应用。简单介绍了移动床生物膜反应器(MBBR)工艺应用的设计参数。     

固定式填充复合床光催化反应器设计影响因素的研究

设计了一种固定式填充复合床光催化反应器，以亚甲基兰为模型污染物，对负载型催化剂在反应器申的设置方式、反应器的外形结构、溶液的pH值和光源的光强等主要因素在设计过程申的影响进行了研究，为该类型光催化反应器工业放大设计提供了理论依据。     

液固两相磁稳定床中试冷模研究

在磁稳定床冷模中以水为液相,非晶态合金催化剂(SRNA-4)为固相,探索磁稳定床反应器流动特性,并考察电磁线圈的放大效应,为工业磁稳定床反应器的设计提供数据。     

丁炔二醇浆态床反应器设计要点

本文以丁炔二醇合成反应器为对象,指出浆态床反应器结构设计的原则与机理,用以指导结构设计的研究结论,并介绍其总体结构、技术参数以及主要零部件的设计要点。实践表明,本文论述的浆态床反应器已成功地在许多工程中得到应用。     

固定床反应器中气液分配器的流体力学性能

设计了一种底部带有碎流板的新型管式气液分配器。以水和空气代替工业上的原油和氢气进行冷模实验。实验过程为:水由水箱经水泵抽出,经液体流量计计量后进入实验塔上部的气液扩散器,气液两相流经急冷箱冷却后同时向下通过分配器。进入到接液装置的液体通过橡胶管导入到放置在地面上的17个标有编号的量筒中,未进入接液装置的液体流入水箱,气体则排放到大气中。最后用U形管差压计测量分配器的压力降。实验研究了该分配器的分配性能、压力降损失、气液相操作弹性和分布不均度,优化并确定该分配器的结构形式和结构参数。结果表明,该分配器的最佳工作条件为:液相量为0.3m³/h左右,气相量为20~30m³/h。     

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.     

分布板对液固流化床换热器颗粒分布的影响

以三维Navier-Stokes方程为控制方程,结合k-ε二方程湍动模型,以直径为1 mm刚玉球作为颗粒相,水为流动相,采用隐式有限体积法对流化床换热器内的液固二项流动进行数值模拟.研究了换热器下管箱安装分布板与否及分布板板面结构形式对颗粒分布的影响,并通过下管箱内压力分布的实验结果对所采用的数值计算方法进行验证.结果...     

大型塔进料分布器二相流场数值分析

以大型塔器常用的双切向环流进料分布器为例,通过数值分析研究了气液二相流体在分布器中的分布规律。选用k-ε湍流模型和Lagrange二相流模型,模拟计算气液二相混合进料时,通过改变液气质量流量比,研究气液二相流动规律、分布器的压降及雾沫夹带,同时与只模拟气相流场的结果进行比较。结果显示,气液混合进料比气相进料时的气体分布不均匀度小,压降和平均湍动能则偏大,气液二相流场的计算更接近实际工况,这为大型塔分布器的设计及确定适宜操作条件提供了理论指导。     

采用填料强化的鼓泡塔直接接触换热性能研究

以正戊烷-水为物系,进行了采用填料强化的鼓泡塔直接接触蒸发换热实验。实验采用顺流操作,考察了分散相流量、温差以及分布器孔径对体积换热系数和汽化高度的影响。实验得出：在戊烷流量为23.868 L/h,分布器孔径为2.5 mm时加填料的鼓泡塔的体积换热系数约为未加填料的2倍;在一定的操作条件下,加填料的鼓泡塔中汽化高度随分散相流量和分布器孔径的增大而增加,随温差的增大而减小;加填料的鼓泡塔中体积换热系数随分散相流量的增加而增加,随分布器孔径的增大而减小,与温差成负幂指数关系。     

Studies on Liquid—Gas and Three‐Phase Fluidized Beds with Pulsating Air Flows

The effects of air‐flow pulsation and water and air flowrates on the hydrodynamics of liquid—gas and three‐phase fluidized beds containing 3‐mm glass beads have been studied in a 90‐mm i.d. column. Under steady‐flow conditions, both types of bed contained a relatively large number of small bubbles. With a pulsing air flow, however, a smaller number of much larger bubbles or slugs were formed. This was attributed to different mechanisms of bubble formation at the distributor. Variations in phase holdup were explained in terms of the effects of the operating parameters on the bubble characteristics.     

一种新型板翅式换热器气液分配器分配特性的敏感性分析

两相流动分配不均是影响板翅式换热器换热效率的主要因素。传统的"先混合,后分配"方法不能解决在导流翅片中流向突变时气液分离引起的气液两相流体分配不均问题,因此采用"先分配,后混合"的理念提出了一种新型的气液分配器,气体和液体分别从各自的通道进入分配器,在分配器内均匀混合后进入换热器的翅片换热通道进行换热。通过对分配器内部流场的数值模拟,发现:分配器的气液分配不均匀度随流量的增加而增加,且不均匀度受液相流量的影响比气相大。该气液分配器的气液分配不均匀度相比传统封头结构降低了一个数量级,能够有效改善板翅式换热器层间通道的气液分配特性,提高板翅式换热器的换热效率。     

Laminar single phase flow distribution in a multi-tube mini-channel heat exchanger using fractal distribution

Mini-channel technology is a promising solution in a world where there is a growing demand for product miniaturization. In this paper a new geometry for a distributor of a multi-tube mini-channel shell and tube exchanger is proposed which should distribute the flow equally over the tubes. The tubes have an internal diameter of 0.5 mm while the shell has a hydraulic diameter of 1.8 mm. The flow in the heat exchanger is pure counter current flow; no baffles have been used in the shell. Experimental data for laminar single phase water in both the tube and shell side are reported. A mathematical model is developed which can predict the performance of the multi-tube mini-channel that uses the newly proposed distributor. This model considers both heat transfer and pressure drop and makes use of prediction methods proposed in the literature for similar geometries. It has been experimentally validated that the newly proposed distributor gives a good distribution for laminar single phase flows. The mathematical model can predict the experimental performance of the multi-tube mini-channel exchanger within 10% accuracy.     

Influence of coalescence behaviour of the liquid and of gas sparging on hydrodynamics and bubble characteristics in a bubble column

This experimental study is aimed at investigating the effect of liquid phase properties and gas distribution on bubble and hydrodynamic characteristics in bubble columns. With the various measuring techniques used, systematic measurements of bubble size, velocity and frequency and gas hold-up are possible. Bubble size distribution and shape factors which are rarely found in literature, are also available. Water–alcohol solutions are used to simulate the behaviour of industrial non-coalescing organic mixtures. The experimental results obtained with three different spargers in the coalescence inhibiting solutions are compared with data on standard coalescing air–water system. Evolutions of bubble characteristics and gas hold-up have been interpreted successfully by considering the simultaneous influence of the hydrodynamic regime of the gas–liquid flow and of the operating regime of the distributor. It has also been put into evidence that bubble frequency measurements are good tools to evaluate distributor efficiency. The influence of the distributor has been shown to be enhanced in non-coalescing media. Bubble shape and bubble size distributions are dramatically modified by addition of minute quantities of alcohol in water. Bimodal distributions can be observed even in the homogeneous regime with orifice nozzle spargers.