1000 MW超超临界机组空冷系统选型设计探讨

文章以山西某工程为例,针对1000MW超超临界空冷机组的特点,介绍了直接空冷和间接空冷方案,并对2种设计方案的特点、经济性等进行了分析,供1000MW机组空冷系统选型设计参考。     

GH141合金环形锻件轧制工艺参数的研究

采用小环模拟的方式，研究了ＧＨ１４１合金轧制工艺参数中变形温度、变形程度对合金组织性能的影响，总结了ＧＨ１４１合金环形锻件的轧制工艺参数。     

Thermal stability of R-134a, R-141b, R-13I1, R-7146, R-125 associated with stainless steel as a containing material

An experimental apparatus for assessing the thermal stability threshold of refrigerant working fluids is described and results for R-134a (1,1,1,2-tetrafluoroethane), R141b (1,1-dichloro-1-fluoroethane), R-13I1 (trifluoromethyl iodide), R-7146 (sulphur hexafluoride), R-125 (pentafluoroethane) are presented. The information is a concern for the design of refrigeration systems, high temperature heat pumps and Organic Rankine Cycles (ORC), for which the above refrigerants are proposed. The method aims to identify a maximum temperature for plant operation in contact with stainless steel and involves the evaluation of four indicators: (1) pressure variation while the fluid is maintained at set temperature; (2) saturation pressure comparison after heat treatment; (3) chemical analysis; and (4) vessel visual inspection after the test session. The highest temperatures at which no evident degradation occured are: 368°C for R-134a; 102°C for R-13I1; 90°C for R-141b; 204°C for R-7146; and 396°C for R-125.     

新络合剂-多羧甲氨基酰胺类化合物的合成及对~(141)Ce的促排效果

本文报道了8个多验甲氨基酰胺类络合剂的合成及对~(141)Ce的促排效果。大鼠实验表明,其中8个络合剂,在注入后8天,使尿,粪中~(141)Ce的排除量为注入量的40—50％,约为对照组的7—10倍;肝中累积量有明显的降低,为对照组的1/2—1/7。     

停炉保护在1 000MW超超临界机组中的应用

某新建1 000 MW超超临界机组在整套试运阶段,多次启停且间隔时间较长。在机组投运前,采取了氨、联氨钝化烘干保护法,氨钝化烘干保护法,氨、联氨湿法保护法对机组进行停炉保护。对这3 种停炉保护方法进行了总结、比较,并对其在机组中的应用效果进行了评价。针对新建超超临界机组,建议在锅炉点火后停炉采用氨钝化烘干保护法,在锅炉未点火、需保养的情况下可采用氨、联氨湿法保护法。     

1 000 MW超超临界机组汽机与锅炉岛施工主吊机械选择与布置

1 000MW超超临界燃煤机组汽机与锅炉岛施工主吊机械的选择与布置充分体现了一个施工企业大型机械装备水平和施工能力。通过玉环、邹县、泰州、外高桥、北仑、宁海等工程的实践, 针对汽机岛、锅炉岛施工主吊机械选择与布置, 从主厂房、锅炉本体、电除尘器等3 个方面进行阐述。     

Development of an ejector cooling system with thermal pumping effect

This paper presents a feasibility study of an ejector cooling system (ECS) that utilizes a multi-function generator (MFG) to eliminate the mechanical pump. The MFG serves as both a pump and a vapor generator. The MFG is designed based on the pressure equilibration between high and low pressures through heating and cooling process. In this design, an ECS that contains no moving components and is entirely powered by heat can be practicable. A prototype using refrigerant R141b as working fluid was constructed and tested in the present study. The experimental results showed that the system coefficient of performance (COP_o) was 0.218 and the cooling capacity was 0.786 kW at generating temperature (T_G) 90 °C, condensing temperature (T_C) 32.4 °C and evaporating temperature (T_E) 8.2 °C. While taking into account the extra heat needed for the MFG operation, the total coefficient of performance (COP_t) is 0.185. It is shown that a continuous operation for the generation of cooling effect in an ECS with MFG can be achieved. This cooling machine can be very reliable since there is no moving part.     

Synthesis of polyesters containing coumarin dimer components by photopolymerization of 7,7′-coumarinyl polymethylene dicarboxylates

Eight 7,7-coumarinyl polymethylene dicarboxylates have been successfully synthesized by solution condensation of 7-hydroxycoumarin (umbelliferone) or 7-hydroxy-4-methylcoumarin (4-methylumbelliferone) with various polymethylene diacid chlorides. Upon benzophenone-sensitized irradiation with 350 nm light, the terminal coumarin chromophores dimerize to form intermolecular cycloadducts or intermolecular polyesters with three kinds of cyclobutanes (syn head-to-head,anti head-to-head,anti head-to-tail), depending on structure of the dicarboxylates and reaction conditions. The structures of the cycloadducts and polyesters have been characterized by¹H NMR spectra. When the methylene units exceed seven, intermolecular reaction becomes predominant and result inanti-rich configuration photo-cyclized products with higher viscosity. Lower polar solvents and 4-methyl substitution in coumarin chromophores also promote intermolecular reaction. The highest viscosity (_red = 0.42 dL/g) is obtained with polyester from 7,7-(4-methyl coumarinyl) decamethylene decarboxylate. Irradiation of the polyesters with 254 nm light leads to symmetric cleavage of the cyclobutane linkage in the main chain.     

超超临界机组用Super304H钢焊接接头的组织和性能

采用光学显微镜、扫描电子显微镜及能谱仪等手段,通过拉伸试验、弯曲试验、冲击试验和硬度试验,研究超超临界机组用Super304H奥氏体耐热钢焊接接头的微观组织和力学性能。结果表明:Super304H钢焊接接头的组织均为γ+析出相,热影响区的晶粒尺寸有明显的长大,焊缝组织是典型的胞状树枝晶,枝晶界上的析出相主要为Nb(C,N)。Super304H钢焊接接头具有较高的强度和良好的塑韧性,但接头的组织形态对韧性有重要影响,粗大的柱状晶是焊缝韧性降低的重要原因,熔合区因Nb(C,N)析出强化硬度较高。     

超声波频率对HCFC-141b水合物结晶过程的影响研究

研究了超声波频率对HCFC-141b(1,1-dichloro-1-fluoroethane)水合物结晶过程的影响,结果表明:超声波能有效改善水合物的结晶;频率f一定时,ti与功率密度Pd成反比,Mf、nfh和Va与Pd成正比;当Pd<750W/cm2时,15kHz的超声波作用下的Mf、nfh和Va高于20kHz的超声波作用下的数值,而750W/cm2相似文献