气流床气化炉激冷环冷态流场数值模拟

针对气流床气化炉激冷室的工作特点,建立了一套激冷室激冷环的冷态流动数学模型,利用Fluent软件,对激冷环气相冷态流场进行数值模拟。通过模拟与实验对比,分析激冷环上不同位置喷嘴的流场分布;通过改变激冷环的进气方式,分析不同进气结构对激冷环上喷嘴速度的影响。结果表明:相比二进气道结构,四进气道结构使得激冷环喷嘴的速度分布相对均匀,能够达到激冷环对合成气强化换热的效果。     

气化炉激冷环受损状况分析与研究

对某煤化工项目中,在用煤气化炉激冷环局部受损状况进行了分析与研究,并提出解决方案。应用Fluent软件对激冷环内冷态介质进行数值模拟,计算结果表明,较高流速的激冷水裹挟着固体颗粒物,是造成激冷环内表面局部冲蚀受损的主要原因之一。根据分析结果,采取局部结构及尺寸优化、改善激冷水水质、降低激冷水流速等措施,实现延长激冷环使用寿命的目的。     

激冷流程气化技术循环气压缩机设备布置的合理性分析

在全世界范围内已实现工业化生产的煤气化技术中,只有壳牌煤气化技术采用了激冷流程,由于该工艺在节能减排降本增效方面突出的优势,未来其他新型煤气化技术也存在采用此工艺的可能。分析和论述了以壳牌煤气化技术为代表的粉煤气化技术(激冷流程)的优势及其广阔的应用前景,着重对目前壳牌煤气化装置循环气压缩机的布置进行分析,对比国内现行的防火设计规范,论证了现有循环气压缩机的布置方案是满足国内现行设计规范要求的,为未来中国其他采用激冷流程的新型煤气化工艺的研究与发展奠定坚实的理论基础。     

基于ASPEN模拟计算的壳牌煤气化装置循环气压缩机激冷比的优化设计

据调查,目前有多套在运行的废锅流程壳牌煤气化装置出现了循环气压缩机激冷气量不足而导致装置负荷无法提升的问题,其主要原因在于原始设计的循环气压缩机能力偏小,特别是在实际运行过程中,煤种发生偏离是导致激冷气压缩机激冷气量不足的另一重要原因。在深入分析导致激冷气量不足的原因的基础上,借助ASPEN模拟软件对循环气压缩机的激冷比进行优化设计,以期为现有的循环气压缩机改造及新建项目提供参考。     

干煤粉气化合成气洗涤塔折流板改造策略及质量要求

介绍了GSP粉煤加压气化激冷流程合成气洗涤系统工艺流程,针对因工艺气扰动合成气洗涤塔内液体造成激冷水泵入口流量波动发生气化炉跳车风险。根据合成气洗涤塔结构及内件形式,对洗涤塔激冷水泵入口管线处进行改造,减少运行过程中大量合成气气泡被带入激冷水管线中。改造效果表明,有效减少了工艺气对合成气洗涤塔内液体的扰动,降低了气化炉烧嘴跳车事件的发生。     

2000 t/d投煤量Shell气化炉的积灰成因机理模拟与分析

针对国内日投煤2 000 t Shell气化炉运行中出现的合成气冷却器(SGC)积灰问题,对气化炉积灰机理进行了模拟分析,揭示其核心问题在于冷热气体的混合不均匀,据此提出了气化炉内部结构的相应改造措施,涉及激冷段及SGC入口段的激冷结构改造,以解决积灰问题,提高气化炉的产气量及延长运行周期。     

德士古气化炉激冷室内部工艺过程的分析

分析了激冷室内的工艺过程，探讨了降气管损坏和合成气带水的原因。     

Shell煤气化装置激冷流程综述

阐述Shell煤气化工艺中粗煤气激冷流程,激冷气的作用,激冷气流程主要设备激冷气压缩机及启动步骤进行简介,Shell气化炉运行过程中实际遇到问题的浅析。     

五环气化炉激冷方式的设计与改造

五环炉原设计激冷方式为水汽激冷,由于采用激冷锅炉给水及部分水蒸气激冷容易导致激冷室内及输气管堵塞,影响气化炉长周期运行。为解决这一难题,结合设计院建议将激冷方式重新设计、改造,由水汽激冷改为气激冷。改造后该系统正常投用,气化炉运行效果良好,从根本上解决了气化炉激冷段和输气管积灰结块现象,实现了气化炉长周期运行。     

Cr-Mo钢复合板厚壁锥体的成形与检验

对煤化工激冷罐锥体的成形加工工艺过程进行了详细的阐述。激冷罐锥体材料采用Cr-Mo钢复合板。由于锥体壁较厚且工况苛刻,因此制造难度较大。该厚壁锥体的制造成功,为采用Cr-Mo钢复合板厚板制造压力容器和其他化工设备提供了可借鉴的经验。     

TEXACO气化炉激冷室下降管传热传质过程模拟

对 TEXACO气化炉激冷室下降管内的传热传质过程建立了数学模型 ,并对数学模型进行了数值计算 ,据此分析了下降管内合成气的温度分布与进口流速等参数的关系 ,为进一步探讨激冷室的工作过程 ,提高气化炉的操作开工率提供了依据。     

SIMULATION OF AEROSOL FORMATION IN GAS-LIQUID CONTACT DEVICES

In gas-liquid contact devices like absorbers, quench coolers, or condensers, aerosols can be formed by spontaneous phase transitions, initiated by homogeneous or heterogeneous nucleation, if a supersaturated gas phase emerges due to simultaneous heat and mass transfer processes or chemical reactions. Typical examples are the absorption of acid gases, like HCl or SO₃, the condensation of solvents in the presence of inert gases, and the humidification of cold gases by hot liquids.

In this article the basic principles of aerosol formation in contact devices are briefly described. A strategy for modeling and simulation of aerosol formation and particle dynamics is discussed. Simulation results generated with the process tool AerCoDe for the countercurrent absorption of HCl and the humidification of air are presented.     

SIMULATION OF AEROSOL FORMATION IN GAS-LIQUID CONTACT DEVICES

In gas-liquid contact devices like absorbers, quench coolers, or condensers, aerosols can be formed by spontaneous phase transitions, initiated by homogeneous or heterogeneous nucleation, if a supersaturated gas phase emerges due to simultaneous heat and mass transfer processes or chemical reactions. Typical examples are the absorption of acid gases, like HCl or SO₃, the condensation of solvents in the presence of inert gases, and the humidification of cold gases by hot liquids.

In this article the basic principles of aerosol formation in contact devices are briefly described. A strategy for modeling and simulation of aerosol formation and particle dynamics is discussed. Simulation results generated with the process tool AerCoDe for the countercurrent absorption of HCl and the humidification of air are presented.     

乙烯装置急冷油系统存在问题的分析

某些乙烯装置的急冷油系统操作数据与设计数据偏离较远，说明设计上存在问题，应从工艺流程设计和模拟计算入手，找到准确的设计方法。     

Solidification of poly(ethylene terephthalate) with incomplete crystallization

Cooling is a critical step in any crystalline polymer molding or extrusion process. A simulation is proposed which will predict the transient temperature and crystallinity profiles developed when a finite polymeric slab comes in contact with a cooling fluid. A generalized, phenomenological model of the crystallization kinetics of polymers is incorporated to account for the effect of the latent heat of crystallization on the thermal history as well as on the crystalline structure at any point in the slab. The model assumes heterogeneous nucleation and temperature-dependent radial growth of spherulites. DSC cooling thermograms for the polymer are used to verify the kinetic model for comparing experimental measurements against simulated results. Observed spherulite sizes should also be matched by the simulation. Kinetic data have been obtained for two grades of poly(ethylene terephthalate) which have the same growth rate expression but different nucleation characteristics. Crystallinity of these two polymers decreases rapidly as either quench temperatures or nucleation densities are decreased independently. Calculations have been carried out for 1/16 in. thick sheets of polymer exposed to a cooling medium with a heat transfer coefficient of 100 Btu/hr/ft²/°F. Temperature gradients are also presented. The simulation can be used for optimizing quench conditions in polyester film extrusion.     

MECHANISM OF THERMAL-SHOCK FAILURE IN ENAMELWARE,AN OVEN-TEST METHOD*

Enameled utensils were tested for thermal-shock resistance by heating in an oven to a predetermined temperature, then quenching with iced water. This process was repeated, following a schedule of successively higher temperatures from 375° to 600°F. until the specimens chipped or withstood heating after the tenth quench. The method is suitable for testing most sizes and shapes of utensils. Data on a wide variety of commercial utensils are included. Photographs show that failures originate in cracks formed during quenching from stresses produced by rapid cooling and shrinking of the surface of the enamel. The chips are usually blown off with considerable force during heating following the quench by steam produced from water which penetrated the cracks during the quench. Evidence is presented that deformation of the pan bottom during heating does not produce thermal shock failures.     

Quench time modeling in propane ultrapyrolysis

Pyrolysis products from industrial cracking furnaces are commonly quenched indirectly in transfer line heat exchangers (TLX). To assess the performance of a TLX for a high severity furnace, a rigorous computer simulation of a TLX tube has been developed. The primary objective was to determine whether this method of indirect quenching can provide the extremely small quench times required for fast ultrapyrolysis reactions. Results indicate that extremely small quench times of approximately 10–15 ms can be achieved, typically dropping the temperature from 1100 to 900K. The model takes into account the effect of the thermal entrance region on heat transfer characteristics and can employ either a 10 equation molecular reaction scheme or an 80 equation radical reaction scheme for propane pyrolysis. The effects of adjusting the main process variables and of coke deposition on quenching performance are also discussed.     

丙烯酸急冷吸收塔工艺改造的研究

现行国内丙烯酸急冷吸收塔塔顶丙烯酸含量较高,产品损失较多,能耗较大;国外采用新工艺将急冷塔改为急冷加吸收的形式,在减少塔顶丙烯酸含量的同时降低了能耗。选择NIQUAC—HOC—HENRY组合模型对现行工艺流程和操作条件进行模拟,结果表明：物流模拟值和实测值吻合良好。将此模型应用到新工艺条件下,比较多个条件下的结果并进行分析,最终选择出最佳的工艺操作条件和塔设备结构参数。     

Improved Design of the Lurgi Reactor for Methanol Synthesis Industry

Current studies are devoted to promote the production yield of the methanol synthesis process for treating large feed capacities in Algerian methanol manufacture industry by designing new reactor technologies. In order to achieve a high yield of methanol, the performance of methanol synthesis is improved by substituting the quench reactor by a new Lurgi reactor. The design of operating parameters of the Lurgi reactor involves the effect of CO₂ injection on methanol production yield and the catalyst deactivation. The simulation results demonstrate that under the same industrial operating conditions the conversion rate of reactants increases from 23 % in the quench reactor to 37 % in the Lurgi reactor and the methanol yield can be increased by 33 % when substituting the quench reactor by the Lurgi reactor     

Liquefaction of coal by SRC-II process: Part V: Dynamic thermal behavior of the reactor

Criteria for identification of the unstable or stable nature of the steady state based on the reactor temperature response to step changes in feed temperature, and a dynamic thermal simulation of SRC-II reactors are developed. These are used in the analysis of a dynamic SRC-II reactor experiment to confirm its unstable operation under normal process conditions. The simulation is used further to study the sensitivity of reactor temperature to changes in feed temperature and to variations in the total heat capacity of the reactor vessel and insulation materials. It is shown that, under normal SRC-II process conditions, it would take about an hour for the reactor temperature to change by ± 10°C, if no controls were used. With quench gas manipulation, the reactor temperature could be maintained within ± 1°C even for a sustained small perturbation in the process conditions. Therefore, in spite of its unstable character, the SRC-II reactors can be readily operated with quench gas manipulation without incurring any major temperature control problems.