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61.
介绍一种出租车计价器的功能要求及其设计方案。在软件Max+PlusⅡ中给出具体设计过程,采用层次化设计方法,对主要电路模块和整个系统进行了仿真验证,实现预定的逻辑功能。该设计具有集成度高、设计周期短、易于修改的特点。 相似文献
62.
Simulation of DME synthesis from coal syngas by kinetics model 总被引:1,自引:0,他引:1
Hyun Min Shim Seung Jong Lee Young Don Yoo Yong Seung Yun Hyung Taek Kim 《Korean Journal of Chemical Engineering》2009,26(3):641-648
DME (Dimethyl Ether) has emerged as a clean alternative fuel for diesel. There are largely two methods for DME synthesis.
A direct method of DME synthesis has been recently developed that has a more compact process than the indirect method. However,
the direct method of DME synthesis has not yet been optimized at the face of its performance: yield and production rate of
DME. In this study it is developed a simulation model through a kinetics model of the ASPEN plus simulator, performed to detect
operating characteristics of DME direct synthesis. An overall DME synthesis process is referenced by experimental data of
3 ton/day (TPD) coal gasification pilot plant located at IAE in Korea. Supplying condition of DME synthesis model is equivalently
set to 80 N/m3 of syngas which is derived from a coal gasification plant. In the simulation it is assumed that the overall DME synthesis
process proceeds with steadystate, vapor-solid reaction with DME catalyst. The physical properties of reactants are governed
by Soave-Redlich-Kwong (SRK) EOS in this model. A reaction model of DME synthesis is considered that is applied with the LHHW
(Langmuir-Hinshelwood Hougen Watson) equation as an adsorption-desorption model on the surface of the DME catalyst. After
adjusting the kinetics of the DME synthesis reaction among reactants with experimental data, the kinetics of the governing
reactions inner DME reactor are modified and coupled with the entire DME synthesis reaction. For validating simulation results
of the DME synthesis model, the obtained simulation results are compared with experimental results: conversion ratio, DME
yield and DME production rate. Then, a sensitivity analysis is performed by effects of operating variables such as pressure,
temperature of the reactor, void fraction of catalyst and H2/CO ratio of supplied syngas with modified model. According to simulation results, optimum operating conditions of DME reactor
are obtained in the range of 265–275 °C and 60 kg/cm2. And DME production rate has a maximum value in the range of 1–1.5 of H2/CO ratio in the syngas composition. 相似文献
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基于Aspen Plus建立了1 MWth煤化学链气化模型,探讨了气化过程中不同煤种(宁夏煤、新疆煤、云南煤)、不同载氧体(赤铁矿、锰矿)、温度、氧/碳摩尔比、压力、水蒸气/煤质量比对合成气组分的影响及实现系统自热平衡运行的条件。结果表明:在700~1200 ℃范围内,随着反应温度升高,3种煤合成气产率及冷煤气效率先增加后趋于平缓;水蒸气/煤质量比在0.5~1.5范围内增大、压力在0.1~3.0 MPa范围内增加都会使合成气产率降低;随氧/碳摩尔比在0.1~1.7范围内增大,合成气产率显著降低,系统由外部供热变为向外放热;当系统实现自热平衡运行时,赤铁矿和天然锰矿载氧体的氧/碳摩尔比分别为1.1和1.5;在保证反应速率和经济成本的前提下,优先选择天然锰矿石作为载氧体。 相似文献
66.
Aspen Plus has become one of the most common process simulation tools for both academia and industrial applications. In the last decade, the number of the papers on Aspen Plus modeling of biomass gasification has significantly increased. This review focuses on recent developments and studies on modeling biomass gasification in Aspen Plus including key aspects such as tar formation and model validation. Accordingly, challenges in modeling due to specific assumptions and limitations will be highlighted to provide a useful basis for researchers and end-users for further process modeling of biomass gasification in Aspen Plus. 相似文献
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68.
《石油化工》2015,44(5):543
提出了一种新型硫酸法C4烷基化生产工艺,丁烯原料在气相状态下进入反应器,与液相异丁烷、浓硫酸混合后,部分丁烯溶于液相,在液相中进行反应;通过控制反应器的压力,部分液相吸收反应热而汽化,使反应温度基本稳定;经气液分离、酸烃分离及产品分馏后,气相丁烯、异丁烷、浓硫酸分别构成循环。采用Aspen Plus过程模拟软件对新工艺过程进行模拟计算的结果表明,在反应器进口压力0.2 MPa、压降4.5 k Pa的条件下,反应器进出口温度均在7.2℃左右,可通过调节反应器压力实现温度的控制;反应器进口液相中烷烯质量比为145∶1,可减少副反应的发生;与传统硫酸法C4烷基化工艺相比,新工艺耗电量可降低30%。 相似文献
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70.
Grain boundary precipitates in Inconel 718 and ATI 718Plus are important to control during hot working processes, since they can control the grain size. Precipitating excessive or insufficient amounts can be detrimental to the final component. Therefore, it is important for manufacturers to understand the formation and kinetics of grain boundary precipitation and the effect this has on mechanical properties. This review considers the background of grain boundary precipitation, including the effect of the thermal stability of γ′ and γ″ phases. In addition, the effect of stress on the grain boundary phases and their precipitation kinetics in different conditions are also included. Also, the impact of grain boundary precipitation on the mechanical properties is explored.
This review was submitted as part of the 2017 Materials Literature Review Prize of the Institute of Materials, Minerals and Mining run by the Editorial Board of MST. Sponsorship of the prize by TWI Ltd is gratefully acknowledged 相似文献