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针对管壳式甲醇反应器环焊缝易受热应力拉裂的问题,开发了一种新型浮头管壳式甲醇反应器.管束可以通过填料函在壳程中自由伸缩,消除了管程和壳程之间由于温差和线膨胀系数不同而产生的热应力,提高了设备安全性.按此设计制造的浮头管壳式甲醇反应器,在某公司甲醇装置上使用6个月证明,该反应器结构可靠,性能优良. 相似文献
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针对某企业蒸汽锅炉消烟除尘系统存在的问题,选用了新型花岗岩水膜除尘器,进行了消烟除尘系统改造,通过改造前后的监测数据对比,表明改造是成功的。 相似文献
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随着输送介质温度的升高,供热管道将出现热伸长现象,该伸长量若不能得到有效补偿,将会使管道承受巨大的应力,从而导致管道严重变形,甚至破裂.支架和热力补偿器是热力管道的重要组成部分,选用或布置时,必须保证管道的稳定性,充分满足管道热位移和热力补偿的要求,避免产生过大的各种应力. 相似文献
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分段进水厌氧折流板反应器(SABR)是一种高效的污水生物处理反应器,流场十分复杂。运用通用商业计算流体力学(CFD)软件Fluent对SABR反应器进行流场模拟,用Solidwork建立反应器流场实体模型,采用分块结构化网格技术实现了适用于复杂形体的分块结构化网格的计算程序,采用修正的k-epsilon双方程湍流模型以及滑移网格法(SG)处理反应区。分别考察了进水流量为0.276,0.420,0.840,1.680 L/h时厌氧反应器的速度场、压力场以及湍动性能。结果表明,计算所选模型能较准确地预测反应器流场情况,模拟结果与实测结果比较符合,具有较高的参考价值,对今后SABR反应器的进一步研究与改进有着十分重要的意义。 相似文献
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《Process Safety and Environmental Protection》2007,85(5):446-449
The dilute acid hydrolysis of grass and cellulose with phosphoric acid was undertaken in a microwave reactor system. The experimental data and reaction kinetic analysis indicate that this is a potential process for cellulose and hemi-cellulose hydrolysis, due to a rapid hydrolysis reaction at moderate temperatures. The optimum conditions for grass hydrolysis were found to be 2.5% phosphoric acid at a temperature of 175°C. It was found that sugar degradation occurred at acid concentrations greater than 2.5% (v/v) and temperatures greater than 175°C. In a further series of experiments, the kinetics of dilute acid hydrolysis of cellulose was investigated varying phosphoric acid concentration and reaction temperatures. The experimental data indicate that the use of microwave technology can successfully facilitate dilute acid hydrolysis of cellulose allowing high yields of glucose in short reaction times. The optimum conditions gave a yield of 90% glucose. A pseudo-homogeneous consecutive first order reaction was assumed and the reaction rate constants were calculated as: k1 = 0.0813 s−1; k2 = 0.0075 s−1, which compare favourably with reaction rate constants found in conventional non-microwave reaction systems. The kinetic analysis would indicate that the primary advantages of employing microwave heating were to: achieve a high rate constant at moderate temperatures: and to prevent ‘hot spot’ formation within the reactor, which would have cause localised degradation of glucose. 相似文献
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在EGSB反应器中添加PVA凝胶颗粒处理高浓度废水。保持进水量一定,逐渐增加反应器内进水COD质量浓度,即2.2~12.9 g/L,相应的有机负荷率是5.4~51.79 g/(L·d)。观察反应器的运行情况,确定有机负荷率在30 g/(L·d)时,COD去除率最高可以达到96%。增大负荷,同时保证进水的p H值是7.0,观察反应器出水p H值与VFA的变化,确定适宜产甲烷菌生长的环境。从收集到的气体体积来看,在一定的范围内,气体产率随着进水负荷的提高而增加,当负荷达到30 g/(L·d)时,气体体积可达38 L(实验最大值)。 相似文献
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介绍了移动床生物膜反应器的工艺原理以及不同于其他生物膜反应器的工艺特点,讨论了MBBR中填料的材质、大小、形状、比重、数量及其有效比表面积,搅拌类型和搅拌方式,有机负荷的大小,水力停留时间等因素对移动床生物膜反应器运行效果的影响,综述了单独MBBR工艺、MBBR与活性污泥共池的工艺、MBBR与其他工艺的组合工艺在污水处理中的应用现状,指出了该项技术的发展方向和趋势. 相似文献
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介绍了火力发电厂设备中的汽轮机的本体结构, 以及汽轮机的安全评价内容.针对汽轮机的本身特点和安全评价内容,提出了两种安全评价方法对汽轮机进行安全评价. 相似文献
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《Process Safety and Environmental Protection》2007,85(5):473-480
Catalytic pyrolysis of pine biomass was carried out in a fluidized bed reactor at 450°C. The acidic catalysts used as bed material in the reactor were β-zeolites with varying silica to alumina ratio, thus having different acid strengths. Quartz sand was used as bed material in the non-catalytic experiment. The yield of the different product phases was clearly influenced by the zeolites acidity. The chemical composition of the bio-oil was dependent on the catalyst. Zeolites with stronger acidity formed less organic oil, and respectively more water and polyaro-matic hydrocarbons than less acidic zeolites. 相似文献
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M.A.S.S. Ravagnani A.R. Righetto M.F. Marquini 《Process Safety and Environmental Protection》2007,85(6):526-532
In this paper, a case study based on an industrial process of ethanol distillation was undertaken. It was aimed to improve the energy and water usage in the process. Pinch Analysis concepts were used to propose a new heat exchanger network and a study was undertaken to the water reuse. The minimization of wastewater is achieved through the exploitation of recycle and reuse opportunities by process modifications. Through these studies, a new streams circuit was obtained, which resulted in a lower consumption of steam and in a reduction in the volume of water collecting of 12 m3 to 1 m3 per tons of crushed sugar cane. Process changes and economical viability were presented. Two kinds of equipment were studied, cooling towers and aspersion tanks. 相似文献
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某恒温间歇反应的热失控研究 总被引:1,自引:0,他引:1
为得到某恒温间歇反应冷却系统临界温度Tc并评估该反应体系的热危险性,基于间歇反应体系热参数的敏感性,探讨数值计算方法和选用4种反应热失控临界判据得到的不同Tc值。结果表明,数值计算方法得到了反应体系的Tc为31.7℃,Semenov判据、Sliding判据、Da/St判据得到的Tc值分别为10℃,17℃和27℃;无量纲绝热温升B给出的结论是,在允许的工艺温度范围内,该反应对任意的冷却系统温度都处于难以控制状态。数值计算方法及各判据得到的Tc的较大差异性说明各方法均有一定的局限性。在运用参数敏感性分析的基础上,结合风险矩阵图方法对系统冷却失效的热危险性进行评估,得到不同Tc下风险可接受、有条件接受及不可接受对应的参数范围的物料累积度Xac与最大反应速率到达时间θ间的关系。 相似文献