气态烃自热转化炉冷态实验研究与数值模拟

采用恒温式热线风速仪测自热转化炉内速度分布,用Realizable κ-ε湍流模型对流场进行模拟,其模拟结果和实验结果比较吻合.轴距小于21d0(喷嘴直径)时,轴线速度的衰减规律不受催化剂床层高度和气速的影响.转化炉内回流量随着轴距的增加,先增大后减小;随着催化剂床层高度的增高,回流比分布曲线变窄,回流量最大值为进口流量的6～7倍;轴距小于20d0,催化剂床层高度对回流比大小的影响不大.在实验条件范围内,改变气速,回流比的大小不变.     

化工自热式转化炉的设计与制造

介绍了自热式转化炉的设计与制造的关键和难点,有针对性地提出了解决难点的特殊设计及工艺方案,对类似设备的设计与制造奠定了基础。     

加压固定床粗煤气再转化工艺自热式转化炉烧嘴选择

烧嘴是自热式转化炉的核心设备,而自热式转化炉是加压固定床粗煤气再转化工艺中的关键设备。为了提高转化效率,首先对比分析了6种烧嘴的应用对象、应用场合、运行优缺点及工艺环境等。通过分析发现,烧嘴在压力从微正压到8.0 MPa、温度880～1700℃内都能运行,且为了保证气化反应的顺利进行,也对烧嘴需具备的性能提出了要求。分析了河南某化工厂试烧褐煤时的粗煤气组成,进一步分析了烧嘴在实际应用中需要满足的条件。结果表明:德士古气化炉煤烧嘴作为粗煤气再转化工艺的实验烧嘴是可行的,能够满足加压固定床煤气化炉产粗煤气再转化工艺要求。     

分解炉循环喂料与物料停留时间分布的关系

:通过对外循环反应器的物料停留时间分布的研究 ,分析了带Pyrotop的分解炉内物料的循环比对物料平均停留时间的影响 ,为工厂的实际操作提供了理论根据     

采取自热式转化 改进合成气生产

本文介绍一种新的生产合成气的方法，即自热式转化法（ＡＴＲ），也就是部分氧化和绝热蒸汽工艺。它可以减少操作费用，降低能耗，减少环境污染，提高燃烧炉效力。     

天然气自热式转化制合成气的Aspen Plus模拟分析

针对富平燃气综合利用项目,选择自热式转化技术对天然气和费托合成尾气进行处理以生产合成气。利用化工流程模拟软件Aspen Plus对天然气自热式转化装置进行了全流程模拟,建立了以RStoic和REquil模块串联的形式进行预转化炉和自热式转化炉模拟的反应器模型,模拟所得的预转化气和转化气组成与设计值十分接近,验证了所建立的模型的准确性。利用所建立的模型进一步模拟、计算得到装置的转化气组成、设备负荷等工艺参数及公用工程消耗数据,并分别对970℃、1 000℃、1 020℃、1 050℃反应温度下的水碳比、氧碳比、CO_2消耗量进行了定性及定量分析,结果可为设计工作及实际生产提供理论数据支持。     

二段转化炉的气体混合器的选择

本文汇集二段转化炉在工业生产中所采用的几种气体混合器结构形式,并进行分析总结,为强化提高二段炉的生产能力,增产氨或甲醇合成气的技术改造所优选或借鉴。     

卧式双轴自清洁反应器粘性体系停留时间分布

在粘性体系中以茜素红为示踪剂,采用紫外光测试技术研究了卧式双轴自清洁反应器中的停留时间分布(RTD),利用返混模型对实验条件下的RTD及返混系数进行了模拟计算,得到了返混系数与雷诺数的关联式。结果表明,反应器的RTD受物料流速、搅拌速率及物料粘度等因素的影响,体系粘度增加返混系数减小;在实验范围内,基于返混模型的计算结果与实验结果基本相符。     

柴油自热重整制氢反应及反应器

设计了带预热段的绝热管式反应器(A型)和带喷嘴及预热段的绝热管式反应器(B型),设计了相应流程并组建了柴油自热重整制氢装置,以直馏柴油为原料,研究了2种反应器内的柴油自热重整制氢反应行为。研究结果表明:2种结构的反应器均能用于柴油自热重整制氢,采用带喷嘴的绝热管式反应器可以确保雾化及气化效果良好,柴油热裂解生成甲烷的反应有助于柴油制氢过程。     

Simulation of autothermal reforming in a staged‐separation membrane reactor for pure hydrogen production

Steam methane reforming with oxygen input is simulated in staged‐separation membrane reactors. The configuration retains the advantage of regular membrane reactors for achieving super‐equilibrium conversion, but reaction and membrane separation are carried out in two separate units. Equilibrium is assumed in the models given the excess of catalyst. The optimal pure hydrogen yield is obtained with 55% of the total membrane area allocated to the first of two modules. The performance of the process with pure oxygen input is only marginally better than with air. Oxygen must be added in split mode to reach autothermal operation for both reformer modules, and the oxygen input to each module depends on the process conditions. The effects of temperature, steam‐to‐carbon ratio and pressure of the reformer and the area of the membrane modules are investigated for various conditions. Compared with a traditional reformer with an ex situ membrane purifier downstream, the staged reactor is capable of much better pure hydrogen yield for the same autothermal reforming operating conditions.     

Synthesis of model-based controllers for an autothermal reactor

Model-based controllers for a bench scale autothermal tubular packed-bed reactor have been formulated using the Internal Model Control (IMC) approach. The Structural Dominance Analysis technique has been used in developing the reduced-order models. Controller performance at robust and sensitive steady states have been assessed through simulations and experiments. Both PI and model-based controllers can regulate reactor operation at robust steady states, but only third order IMC controllers are able to regulate reactor operation at the sensitive steady state.     

Residence time distribution in a single‐phase rotor–stator spinning disk reactor

A reactor model for the single‐phase rotor–stator spinning disk reactor based on residence time distribution measurements is described. For the experimental validation of the model, the axial clearance between the rotor and both stators is varied from 1.0 × 10^?3 to 3.0 × 10^?3 m, the rotational disk speed is varied from 50 to 2000 RPM, and the volumetric flow rate is varied from 7.5 × 10^?6 to 22.5 × 10^?6 m³ s^?1. Tracer injection experiments show that the residence time distribution can be described by a plug flow model in combination with 2–3 ideally stirred tanks‐in‐series. The resulting reactor model is explained with the effect of turbulence, the formation of Von Kármán and Bödewadt boundary layers, and the effect of the volumetric flow rate. © 2013 American Institute of Chemical Engineers AIChE J, 59: 2686–2693, 2013     

Dynamic behavior of a continuous autothermal isobutylene polymerization reactor

Industrial autothermal cationic isobutylene polymerization reactors may present very complex dynamic behavior and difficult operation. A mathemathical model was developed to describe the operation of an autothermal solution industrial reactor, and some possible sources of complex dynamical behavior were analyzed. The results obtained indicate that the most probable source of the complex behavior observed industrially is the existence of adventitious impurities in the feeed stream. The effects caused by the presence of adventitious impurities on process operation and product properties were investigated for both polymerization and oligomerization. In the first case, impurities influence the reactor productivity but do not change the polymer quality. In the oligomerization, both the polymer quality and the reactor productivity are seriously affected by the existence of impurities in the feed stream. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 65: 1403–1413, 1997     

N形折流反应器内颗粒停留时间分布研究

针对磷石膏矿化反应在搅拌反应器中易发生沉积形成死角的缺点,提出颗粒流化状态良好的内置双层导流筒的N形液固折流反应器,采用计算流体力学软件(CFD)模拟得到石膏颗粒在反应器中平均停留时间,并运用多釜串联模型来表达不同外循环量、进出料流量和颗粒不同粒径条件下反应器的返混程度。结果表明:在泵循环流量1.35、3.00、5.00 m~3/h条件下,模拟结果和实验结果吻合较好;反应器级数为1~3,反应器靠近全混流,理论级数、平均停留时间与进出料流量和泵循环流量成反比;磷石膏颗粒粒径越大,平均停留时间越长,粒径100μm的颗粒平均停留时间为71.5 min,而15μm的颗粒只有52.0 min。     

Machine learning-assisted multiscale modeling of an autothermal fixed-bed reactor for methanol to propylene process

The current commercial multistage reactor for methanol to propylene (MTP) process suffers from poor propylene selectivity and catalyst efficiency, mainly because of the low inlet methanol concentration and long residence time. In this work, we proposed an autothermal co-current flow reactor for MTP process, where the reaction heat is continuously removed through heat exchange with cold reactants, thus single-stage reactor can be used with higher methanol inlet concentration. The reactor feasibility was investigated by a three-dimensional multiscale model, in which the diffusion–reaction interaction inside catalyst particle was described by a neural network model trained by machine learning. With the feeding methanol fraction increasing to 30%, propylene selectivity reaches 82.27% while the space velocity approaches 2.68 g_MeOH g_cat⁻¹ h⁻¹ at 99.97% methanol conversion, about 1.4 and 3.8 times those of a commercial multibed reactor, respectively. With proper catalyst bed dilution, the reaction temperature is well controlled between 700 and 754 K.     

注塑螺杆计量段物料的停留时间分布

根据注塑螺杆的工作特点,计算了计量段的停留时间分布函数及表征计量段纵向混合能力的优化目标函数停留时间分布函数的方差。通过对无量纲最短停留时间的分析,得到了计量段物料的停留时间分布函数及其方差的影响参数。     

Detailed analysis of the particle residence time distribution in a pressurized drop-tube reactor

Solid fuel conversion in a pressurized drop-tube reactor is studied in detail using a three-dimensional computational fluid dynamics (CFD) model. The main focus is on analyzing individual particle trajectories and residence times, as these data are crucial for the precise experimental estimation of heterogeneous reaction kinetics. The numerical results were substantiated by radioactive tracer measurements carried out in different operating conditions. The numerical results reveal a complex gas flow that is affected by buoyancy due to a non-homogeneous temperature distribution, which has a strong affect on the trajectories of particular particle size fractions. In this case, empirical residence time correlations for particles, as commonly used for the evaluation of heterogeneous kinetic measurements, lose their validity since the assumption of a plug flow is no longer valid. It can be shown that if CFD-assisted data evaluation is used, a significant improvement in the measured heterogeneous reaction kinetics is feasible.