LNG装置封闭式地面火炬系统安全设计

介绍了液化天然气装置地面火炬系统主要组成,结合项目实例,对地面火炬管排放管道安全设计、分液罐设置、地面火炬应用及总图布置中对地面火炬安全距离要求进行分析,为液化天然气装置地面火炬的安全设计提供参考。     

地面火炬在重油加氢装置上的选型和应用

地面火炬是处理石化装置开停工、停水停电等紧急状态下及时泄压、排放废气的安全设施,关系着全厂的生产安全。以某重油加氢装置的地面火炬为例,介绍了地面火炬的结构特点和优势,说明地面火炬是如何根据给定条件来选型,阐述该地面火炬在生产装置的应用情况。     

高架火炬与地面火炬的比较

介绍高架火炬与地面火炬的特点,分别从安全、环保、占地、投资成本等方面对高架火炬和地面火炬进行分析对比。     

封闭式地面火炬在LNG接收站的应用

通过对高架火炬与地面火炬特点的分析,针对LNG接收站火炬系统设计中应考虑的主要因素,结合封闭式地面火炬放空系统在LNG接收站的应用实例,对封闭式地面火炬放空系统在放空气条件、多级燃烧及分级控制、关键设备配置、热辐射、光污染、噪音等方面进行简要分析,探讨封闭式地面火炬在LNG接收站的应用,对实际工程和项目中具有一定的指导和借鉴意义。     

初探多点式地面火炬的安全环保性能

20世纪70年代,国外开始运用地面火炬处理大型装置排放的火炬气如图1所示。2012年12月,国内第一套多点式地面火炬在上海赛科投用。中韩乙烯是继赛科石化,第二家使用多点式地面火炬技术的乙烯厂。该厂配置有烯烃、聚烯烃2套地面火炬,2012年12月投用。其中,烯烃火炬最大排放量为1670t／h,用于处理装置及罐区在正常、开停工及事故状态下排放的高压火炬气。     

火炬高度的主要影响因素

阐述了化工厂火炬高度的确定与排放介质特性、最大排放量及放热量、大气环境、地面允许热辐射强度、热辐射半径、允许大气污染物落地浓度、火炬自身结构设计等多种因素有关。结合特定的工艺流程,论述了火炬出口风速、地面允许热辐射强度与热辐射半径为影响火炬高度最主要的因素,火炬高度与火炬出口风速成正比,与地面允许热辐射强度和热辐射半径成反比。除此之外,火炬高度的确定还应结合投资、安全、环保、操作、检修及当地规划等方面综合考虑。     

大型石油化工装置火炬系统的设置

我国石化工业的迅猛发展呈现出规模扩大、联建联产和公用工程集中供应的特点，为保证装置系统运行安全和保护环境，通常设置火炬系统对生产运行各种工况下的火炬气作燃烧处理。火炬系统的设置必须以安全、环保为原则，火炬设计中必须对处理能力、热辐射、SO2落地浓度、长明灯等环节进行详细计算。火炬类型包括高架火炬和地面火炬，从处理能力、燃烧效率、环境保护及公用工程消耗等方面比较，地面火炬有其明显的优势。如果对地面火炬在事故状况下的燃烧控制、尾气处理、防辐射、降噪等技术环节进行进一步调整改进，它将成为石化装置火炬系统未来发展的主要选项。     

码头罐区的地面火炬系统设计

为了保证事故时可燃气体的安全排放,石化装置需要设置火炬系统。本文以董家口某码头罐区为例,对地面火炬系统的设计进行了分析和探讨:主要从火炬系统排放量确定、火炬管网计算、分液罐计算、安全防护距离设置几个方面详细介绍了设置地面火炬的方法。     

火炬计算的参数分析

通过对化工装置中火炬的计算,分析了火炬计算中影响高空火炬高度和直径的主要参数;对国内目前应用较少的地面火炬的计算进行了初步探讨。结果表明,影响火炬计算结果的最主要的因素为火炬气流量以及人为规定的热辐射强度等,在排放量为200 t/h、热辐射强度为1.58 kW/m²要求下,高空火炬烟囱直径和高度分别约为0.82 m和60 m;地面火炬的安全距离必须大于30.3 m。     

大型煤化工联合装置火炬系统的设置

通过介绍大型煤化工火炬气的特点、比较高架和地面火炬的优劣,探讨了煤化工火炬系统的设置原则和内容。     

氯丁胶乳砂浆在尿素厂房维修中的应用

根据尿素包装厂房出现的腐蚀现象和产生原因确定了整改思路,经过性能和价格比较,选用性价比高的氯丁胶乳砂浆对腐蚀的地面进行维修.介绍了应用时氯丁胶乳砂浆的配比、施工程序和要点.施工后解决了楼面面层起砂开裂、缝隙渗漏问题,可提高厂房的使用寿命.     

Correlation of 13C‐NMR analysis with fungal decay tests of polymeric structural wood constituents. II. Ground contact tests

Heat treatment at relatively high temperatures (ranging from 150°C to 260°C) appear to be an effective method to improve the durability of wood. This study investigated the reasons for the decay resistance of heat‐treated and untreated wood as composed of polymeric structural constituents by solid‐state CP‐MAS ¹³C‐NMR analysis after fungal exposure in ground contact. An industrially used two‐stage heat treatment method under relatively mild conditions (<200°C) was used to treat the samples. Fungal exposure in ground contact resulted in strong degradation of the carbohydrates (cellulose and hemicellulose) of treated and untreated Scots pine, Radiata pine, and Simaruba. Fungal attack of the carbohydrates appeared to occur mainly at C4, resulting in cleavage and eventually depolymerization of cellulose and hemicellulose. The CP‐MAS ¹³C‐NMR spectra of the heat‐treated wood revealed similarities but also clear differences after fungal exposure in ground contact with the untreated wood. In ground contact fungi appeared to attack the carbohydrates of heat‐treated wood at C1 and possibly at C4 in order to cleave and eventually depolymerize cellulose and hemicellulose. An attack on the out‐of‐the‐ring alcoholic group, ? CH₂OH, of the carbohydrates of the heat‐treated wood was observed (particularly in treated Radiata pine). The fungus possibly tried to cleave the out‐of‐the‐ring CH2? OH group on the main H‐bond fixing sites of the crystalline cellulose structure in order to open the cellulose crystalline structure to an amorphous structure to decrease its water repellency and facilitate enzymatic cellulose degradation; this was also observed, but to a lesser extent, in untreated Radiata pine and untreated Scots pine. The opening of the glucose pyranose ring in heat‐treated Simaruba after fungal exposure, not observed in the untreated wood, was remarkable, and the thermal degradation of alpha‐arabinofuranose during heat treatment indicated more extensive decay. Demethoxylation and ring opening of the aromatic structure of lignin were observed, especially in the heat‐treated Radiata pine, Douglas fir, and Simaruba. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 616–622, 2006     

Transition Structures of the Electrocyclic Reactions of cis,cis,cis-1,3,5-Cyclooctatriene

The electrocyclic reactions of cis,cis,cis-1,3,5-cyclooctatriene have been studied using ab initio molecular orbital theory. cis,cis,cis-1,3,5-cyclooctatriene can undergo an electrocyclic ring opening in a conrotatory fashion to form cis,cis-1,3,5,7-octatetraene and a disrotatory electrocyclization to form bicyclo[4.2.0]octa-2,4-diene. The transition structures for these electrocyclic reactions have been located. Geometry optimizations employed restricted Hartree-Fock calculations and the 3–21G and 6–31G* basis sets. Electron correlation energies were calculated using second-order, and in some cases fourth-order, Møller-Plesset theory. Scaled RHF/6–31G* force constants were employed in the prediction of secondary deuterium isotope effects for the conrotatory ring opening. The ground state of cis,cis,cis-1,3,5-cyclooctatriene exists in a twist-boat conformation with staggering at the saturated linkage. The transition structure for the conrotatory electrocyclic ring opening to form cis,cis-1,3,5,7-octatetraene has a helical structure, which has implications for the stereoselectivities of ring closure of 1-substituted-cis,cis-1,3,5,7-octatetraenes. The disrotatory transition structure for the electrocyclization to form bicyclo[4.2.0]octa-2,4-diene is strongly distorted from C_s symmetry, in contrast to the transition structure for the disrotatory electrocyclization of cis-1,3,5-hexatriene. This distortion is caused by staggering about the saturated linkage.     

Zum Stand der Kohlevergasung

Gasification of coal – a status report . On the basis of industrially available conventional coal gasification processes (Winkler, Koppers-Totzek, and Lurgi pressure gasification) the paper describes developmental trends in such processes. Elevated operating pressure is a common feature of all new processes, thus opening up new applications. An economic incentive to the development of new gasification processes also comes from combinations with new technologies, e. g. with direct reduction. Moreover, an advanced version of the high-temperature Winkler process is described and evaluated in comparison with conventional commercial processes. Apart from processes conducted above ground, recent developments also include thoughts about underground gasification.     

Extraction of oil from meadowfoam flakes

As part of a program to improve meadowfoam seed processing, the authors examined the effects of seed moisture, seed temperature, and flaking roll opening on oil extraction efficiency in meadowfoam flakes. Flakes were prepared using a Wolf Mill with dual horizontal, unheated 12-in. diameter rolls. Roll openings of 0.005, 0.013, and 0.020 in. (0.127, 0.330, and 0.508 mm, respectively) gave average flake thicknesses of 0.013, 0.021, and 0.031 in., respectively (0.330, 0.533, and 0.787 mm). Seed moistures of 9, 12, and 15% and seed temperatures of 65, 190, and 210°F (18, 88, and 99°C) chosen for flaking were known to provide a range of conditions suitable for enzyme inactivation during seed cooking prior to flaking. Experimental flakes were examined for extractable oil content (petroleum ether extraction); this was compared to total oil content (31.5%) determined on finely ground flakes. Roll opening was the dominant variable determining flake thickness, the primary parameter affecting oil extraction efficiency. Thus, the thinnest flakes at 0.013 in. were only slightly less extractable (29.8%) than finely ground flakes (31.5%), but intermediate (0.021 in.) and thick (0.031 in.) flakes were significantly less extractable (28.0 and 26.0%, respectively). There was a slight but significant (P<0.01) trend toward thicker flakes with increasing seed moisture (15>12>9%) during flaking. A similar trend to thicker flakes with increasing temperature was significant (P<0.01) only for the thickest flakes produced at the largest roll opening (0.020 in.). Lower seed moisture and higher seed temperature significantly impacted extractable oil content of the thickest flakes, but negligibly affected extractability of the thinnest flakes. The authors conclude that meadowfoam flakes must be as thin as possible (e.g., <0.015 in.) for efficient oil extraction. Further, seed cooking temperatures >190°F at moistures >10% and <15% that are adequate for efficient enzyme inactivation in the whole seed are also suitable for seed flaking.     

肘杆机构开启力设计计算

本文在力学分析的基础上,推导出开启力的计算公式,分析了开启过程中力放大比及开启力的特性,并提出了新的机型以降低开启力。     

干式气体端面密封的开启特性

鉴于干式气体密封启动过程的重要工程意义,基于稳态分析方法研究了该种密封的开启特性。根据开启临界气膜厚度的假设,提出了用于分析干式气体密封开启性能的判据--开启临界转速。研究了启动过程中,气膜厚度、开启力、气膜刚度、泄漏量、摩擦扭矩和摩擦功耗等密封性能参数的变化规律。分析了操作参数和端面结构参数对开启性能的影响。研究表明,启动过程中,密封的特性参数在开启临界气膜厚度附近快速变化;密封操作压力对开启临界转速有较大影响,通过改变端面结构参数可以改变密封的开启临界转速,改变开启性能。提供了一种用于分析密封开启性能的研究方法,可辅助密封端面结构设计和指导启动和停车过程操作。     

实验室开放的探索与实践

实验室开放是目前高校实验教学改革的重要内容,是培养创新型和应用型人才的有效途径。本文结合湖南工业大学生物技术实验室实施开放性实验教学的实践,对实验室开放教学的意义和主要类型进行了探讨,并提出了目前实验室开放带来的问题以及解决这些问题的建议,为推动实验室开放教学提供借鉴。     

浅析压力容器常规设计规范中的开孔补强设计

对规范GB150、ASME及HG20582中的开孔补强方法进行了比较,介绍了等面积法和压力面积法两种开孔补强方法,讨论了常规规范设计开孔补强的方法,提出按国家标准GB150设计开孔补强时,可以采用行业标准HG20582作为参考的设计思路。     

对影响唐山市市区学校体育场馆对外开放因素的调查研究

采用文献资料法、访问法、问卷凋查法及数理统计法等研究方法，对唐山市市区30所学校体育场馆的拥有量、开放情况及影响开放的因素进行调查研究，在理论上找出影响学校场馆对外开放的主要凶素并提出合理化建议。为唐山市市区学校体育场馆的对外开放奠定基础，为推动唐山市全民健身运动的快速发展做贡献。