共查询到19条相似文献,搜索用时 140 毫秒
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针对以天然气为原料气的甲醇装置中换热式纯氧两段转化工艺,为扩大甲醇生产能力,在不改变空分系统的基础上讨论了改造之后的工艺,根据反应方程式并结合实际运行情况,利用物料平衡、热量平衡及物质守恒原理,对物料及能量变化进行了分析,得到了合适的氢碳比和应加入的二氧化碳的量.同时对改造前后转化工艺的情况进行了比较. 相似文献
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以山东某地方炼油厂1.0 Mt/a汽柴油加氢精制装置扩能改造至1.2 Mt/a为目标,在满足目标产品质量要求的前提下,对装置扩能改造前后原料油性质、加工比例、产品质量标准、主要工艺参数、物料平衡和热量平衡进行对比和分析,并结合装置的全流程工艺模拟计算和主要设备核算分析,找出了原装置工艺和主要设备瓶颈,并有针对性的提出了具体改造措施。同时对装置扩能改造至1.5 Mt/a的可能性做了探索性分析。 相似文献
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对MTBE装置2001年采用混相床——催化蒸馏深度转化合成MTBE工艺进行了介绍,在2002年7月24日对MTBE装置进行了标定,装置在100%(碳四处理量)负荷下的物料平衡情况下的产品质量和能耗情况与设计值进行比较和讨论,通过分析MTBE装置标定结果,无论是在生产能力上,还是在能耗上均达到设计要求。 相似文献
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通过对聚酰胺66直纺大容量聚合装置的技术改造及工艺研究,对聚合关键装置的物料平衡、热量平衡、反应机制、控制及输送系统等的研究设计,对盐预热器、浓缩槽、减压器、聚合器、输送泵等关键装备的增容改造,延长了缩聚时间,加快了水分蒸发或脱水速率,实现了高黏聚合物连续稳定控制.通过聚合装置及关键工艺控制等方面的研究,单线纺丝产能突... 相似文献
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通过对炭黑裂解炉内物料反应及物料平衡的计算与分析,针对炉况,我们进行改造,改半密封为全密封,减少系统负压,改变炉结构等,提高尾气中的氢气含量,降低了炭黑生产成本。 相似文献
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王金铭 《硫磷设计与粉体工程》1998,(1)
简述了该公司AZF工艺在生产DAP时必须使用两只管式反应器,生产NPK时只需用一只管式反应器的情况,并从物料及热量平衡方面对该种操作方式进行了理论分析。并介绍了DAP—NPK—DAP的生产切换方式。 相似文献
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本文以驰放气制甲醇装置为研究对象,采用Aspen进行工艺计算,对关键工艺参数及关键设备进行优化设计,并对全流程进行模拟获得物料平衡及热量平衡等相关数据,为今后的操作及优化工作提供很好的参考。 相似文献
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对UOP工艺包的应用、原料油变化情况、装置产品性质、催化剂的使用情况、开工操作情况、装置生产物料平衡情况进行了对比和分析,表明UOP催化裂化工艺包在催化原料油变化的情况下仍然能达到比较理想的使用效果,UOP工艺包先进技术得到了充分应用,UOP工艺技术在该装置应用非常成功。 相似文献
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Chemical processes and their flow-sheets are systems and as with all systems one cannot optimise each part alone and expect to get an optimal process. One also has to take into account the connections and interactions between the parts of the systems in order to achieve the global optimum. In this paper fundamental thermodynamics will be used to show how to achieve an optimal solution. A coal-to-liquids (CTL) process will be used to illustrate the method.The overall material balance for a process will be looked at first. This material balance must include the constraints such as the energy (heat and work) balance and thus must include the feed streams that supply utilities, such as heat and electricity to the process. The best material balance ensures that as much of the feed material ends up in the product. In the examples discussed, focus will be on ensuring that as much of the carbon in the feed as possible ends up in the hydrocarbon product; the carbon from the feed that does not report to the product is emitted from the process as CO2 which is undesirable for a number of reasons.The resulting overall material balance is then regarded as the process target, since it is the “best” material balance. Furthermore, the manner in which energy (heat and work) is added or removed from a process, affects the material balance by introducing irreversibilities. The greater these irreversibilities are, the further the process operates from the process target, implying that the process produces more CO2 per mole of product produced.Many processes, such as CTL, require substantial quantities of work to be added. It is shown that this may be done by designing the overall process such that the process itself is effectively a heat engine. Thus heat at high temperature is added in an endothermic, high temperature sub-process (e.g. gasification) and (less) heat is rejected at a lower temperature from an exothermic, low temperature sub-process (e.g. Fischer–Tropsch synthesis). Just as in a heat engine, there is a relationship between the values of the high and low temperatures, the quantities of heat flowing in and out of the sub processes and the amount of work added to the overall process. One can note that any stream has an enthalpy and a temperature and these two together can be used to describe the work content of this stream.The Carnot temperature for each sub-process is defined as the temperature at which the heat added to the sub-process takes with it the work content required by the sub-process. The bigger the difference between the actual operating temperature and the Carnot temperature, the more irreversible the process is and the further away the process operates from the process target.A CTL process has been chosen to apply the methods in order to obtain the process target and the overall material balances for different options. It is shown that there are different ways of arranging the heat engine for CTL, for example indirect or direct liquefaction, and that the direct route has higher carbon efficiency than the indirect route. However it is shown that one can use the ideas in the paper to synthesise a new route for CTL where rather than gasifying to syngas, one gasifies to hydrogen and carbon dioxide followed by the FT synthesis reaction. In this way one can show that this indirect CTL route is nearly as efficient as the direct route. 相似文献
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《Chemical engineering science》1985,40(7):1069-1076
Adsorption experiments were carried out with a column packed with activated carbon particles, subject to a step input of carbon dioxide at the column inlet. From the measurements of a thermal wave advancing in the column the adsorption equilibrium constant, heat of adsorption and overall heat transfer coefficient were determined. Theoretical parameter sensitivity test also indicates that the adsorption equilibrium constant, heat of adsorption and overall heat transfer coefficient are the parameters of significance in this non-isothermal adsorption system. Discussion is also given on a heat generation and loss balance condition. 相似文献
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从理论到实际剖析了煤气炉存在的三大矛盾(吹风与制气、上吹与下吹、加碳与排渣)和三大平衡(物料平衡与碳平衡、热平衡、化学平衡)对提高煤气炉的气化强度和降低煤耗的重要性. 相似文献
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Measurement of metabolic heat in a production-scale bioreactor by continuous and dynamic calorimetry
Mustafa Türker 《Chemical Engineering Communications》2013,200(5-8):573-598
Measurement of metabolic heat has been attempted in an industrial-scale bioreactor using continuous and dynamic heat balance calorimetry. The contributions of individual heat sources influencing the temperature of the broth were evaluated and the magnitude of metabolic heat was calculated from general energy balance. Good correlations were obtained between oxygen uptake rate (OUR) and metabolic heat with heat yield under continuous and dynamic conditions with the values of Y Q/O =444 kJ/mole O 2 and Y Q/O =431 kJ/mole O 2 , respectively. There was also correlation between biomass production and heat generation. The value of heat yield, Y Q/X , was calculated to be 14546 kJ/kg; however, this was not constant and slightly decreased towards the end of fermentation. A similar value for heat yield was obtained under dynamic conditions and found to be 14667 kJ/kg. The consistency of experimental data was checked using carbon, electron, and heat balances. It was shown that reasonable accuracy could be achieved in an industrial environment. The difficult-to-measure variable biomass concentration was estimated using continuous metabolic heat flux, and good correlation was obtained between measured and estimated biomass concentrations. The results of this study suggest that heat balance around an industrial bioreactor can be simplified by accurately identifying individual heat sources as opposed to laboratory bioreactors where the contribution of each source can have significant impact. This reduces the number of measurements for accurate heat balance and makes use of heat balance feasible in a large scale. 相似文献
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MEASUREMENT OF METABOLIC HEAT IN A PRODUCTION-SCALE BIOREACTOR BY CONTINUOUS AND DYNAMIC CALORIMETRY
Measurement of metabolic heat has been attempted in an industrial-scale bioreactor using continuous and dynamic heat balance calorimetry. The contributions of individual heat sources influencing the temperature of the broth were evaluated and the magnitude of metabolic heat was calculated from general energy balance. Good correlations were obtained between oxygen uptake rate (OUR) and metabolic heat with heat yield under continuous and dynamic conditions with the values of Y Q/O =444 kJ/mole O 2 and Y Q/O =431 kJ/mole O 2 , respectively. There was also correlation between biomass production and heat generation. The value of heat yield, Y Q/X , was calculated to be 14546 kJ/kg; however, this was not constant and slightly decreased towards the end of fermentation. A similar value for heat yield was obtained under dynamic conditions and found to be 14667 kJ/kg. The consistency of experimental data was checked using carbon, electron, and heat balances. It was shown that reasonable accuracy could be achieved in an industrial environment. The difficult-to-measure variable biomass concentration was estimated using continuous metabolic heat flux, and good correlation was obtained between measured and estimated biomass concentrations. The results of this study suggest that heat balance around an industrial bioreactor can be simplified by accurately identifying individual heat sources as opposed to laboratory bioreactors where the contribution of each source can have significant impact. This reduces the number of measurements for accurate heat balance and makes use of heat balance feasible in a large scale. 相似文献
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We have recently reported that onion-like shell-shaped carbon nanoparticles of high crystallinity could be generated through critical transition in the acetylene flow irradiated by a cw infrared CO2 laser [Choi et al. Advanced Materials 2004;16:1721-25]. This transition appeared as the temperature jump above a threshold value of the laser irradiance. The present paper explains the origin of this recent discovery. The heat balance on the surface of the growing particle is shown to allow the existence of two stable particle temperatures. Then, the temperature jump observed in our recent study is a transition from the low temperature regime to the high temperature regime. Implications of the finding for the processes of the carbon nanoparticle formation from hydrocarbons are also discussed. 相似文献
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Diffusion and reactions in a porous pellet are treated as transient, nonisothermal, nonisobaric processes. Continuity and energy balance equations are solved simultaneously for temperature and concentration profiles in the pellet. Conductive, convective as well as radiative heat transfer are included. The ‘dusty gas’ flux model is used to describe the transport of diffusing gases. Viscous, bulk and concentration gradient terms have been included. Structural changes with reaction are accounted by considering the effect of changing grain radius on porosity and pore diameter. The model predictions match conversion trends for carbon gasification over a temperature range of 800 to 1100°C investigated experimentally. 相似文献