油管电热清防蜡技术在强水敏油田的应用

江苏油田的庄 2、韦 2油田属强水敏油田 ,采用热 (水 )洗油井和化学清防蜡效果较差 ,两油田每年因洗井造成地层污染影响的产量损失在 5 0 0 0t以上 ,约占油田产量的 4 5 %。根据集肤效应 ,采用油管电热清蜡技术 ,在含水小于 6 0 %、井斜小于 4 0°的油井上可正常使用 ,一般通电加热 4 0～ 80min后 ,油井井口温度能达到 5 0℃左右 ,最高可达到 6 5℃以上 ,连续加热 5～ 6h即可达到清蜡目的 ,电热清蜡为周期 6 0～ 90d。影响电热清蜡主要指标因素是油井的产液量 ,产液量越小 ,所需要的加热电流和加热电压也越小 ,井口温度达到最高值越低 ,清蜡效果越差。试验的 7口井平均年度投入产出比达到 1∶5 ,经济效益和社会效益十分明显。     

Comparative effects of cobalt carboxylates on the thermo‐oxidative degradation of LDPE films

This article reports the effect of three cobalt carboxylates—cobalt stearate (CoSt₃), cobalt palmitate (CoPal₃), and cobalt laurate (CoLau₃)—on the thermo‐oxidative degradation of low‐density polyethylene (LDPE) films prepared by sheeting process. The carboxylates were blended with LDPE in the concentration range of 0.05–0.2% (w/w). The degradation was monitored by techniques such as FTIR spectroscopy, change in the mechanical properties (tensile strength and elongation at break), viscometry, surface electron microscopy, melt flow index measurements, and apparent density measurements. Studies indicate that films containing these additives are highly susceptible to thermo‐oxidative degradation. Oxygen containing functionalities such as carbonyl and vinyl species are generated on the surface of polyethylene because of thermo‐oxidation, as indicated by FTIR studies. This oxidative process is accelerated in the presence of cobalt carboxylates. The degradation of LDPE was found to increase proportionally with concentration as well as with increasing chain length of the cobalt carboxylate, and follow the order CoSt₃ > CoPal₃ > CoLau₃. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 3758–3765, 2007     

珍珠粉、珍珠层粉、珍珠母粉的热重及热重动力学

采用热重及热重动力学方法 ,分别研究珍珠粉、珍珠层粉和珍珠母粉的热分解过程及其反应机理。结果表明 ,珍珠粉和珍珠层粉的热分解可分为二个阶段 :第一阶段为 2 50～ 370℃之间 ,失重率约 3% ,反应级数为 1 .6,活化能为 1 0 5～ 1 1 0 k J/ mol属于有机质的热分解 ;第二阶段为 60 0～ 770℃ ,失重率约为 40 % ,反应级数为 1 .3,活化能为 2 80～ 2 90 k J/ mol,属于碳酸钙的分解。珍珠母粉在 2 50～ 370℃之间不存在明显的失重。根据这一现象 ,可以通过热重分析来鉴别珍珠及其制品。     

热化学反应法镁合金陶瓷涂层的制备及性能的影响

采用热化学反应法在镁合金基体上制备陶瓷涂层,并对涂层进行耐磨、耐蚀等性能分析.通过XRD物相分析,涂层中有新相生成.且涂层相对基体耐磨、耐蚀性能均有所提高.     

等离子喷涂纳米ZrO_2陶瓷表面涂层的热震性能研究

对比研究了等离子喷涂Y_2O_3稳定的纳米与微米ZrO_2涂层的组织结构及性能。结果表明,两种涂层有不同的相结构;纳米ZrO_2涂层组织更加细密,铺展性更好,气孔率较低;两种涂层硬度相近;纳米ZrO_2涂层的热震性能明显高于微米ZrO_2涂层。     

Two‐phase thermo‐mechanical and macrosegregation modelling of binary alloys solidification with emphasis on the secondary cooling stage of steel slab continuous casting processes

As an approach towards a better modelling of solidification problems, we introduce a thermo‐mechanical and macrosegregation model that considers a solidifying alloy as a binary mixture made of a liquid and a solid phase. Macroscopic conservation laws for mass, momentum and solute are obtained by spatial averaging of the respective microscopic conservation equations. Assuming local thermal equilibrium, a single equation for the conservation of the mixture energy is then written. A single equation can be obtained for the solute as well by invoking a proper microsegregation rule. The numerical implementation in a two‐dimensional finite element code is then detailed. Lastly, some examples of simulations of academic tests as well as industrial applications for continuous casting of steel slabs are discussed. They particularly enlighten the ability of the formulation to describe the formation of central macrosegregation during the secondary cooling of slab continuous casting processes. Copyright © 2006 John Wiley & Sons, Ltd.     

Mixed finite element method for coupled thermo‐hydro‐mechanical process in poro‐elasto‐plastic media at large strains

A mixed finite element for coupled thermo‐hydro‐mechanical (THM) analysis in unsaturated porous media is proposed. Displacements, strains, the net stresses for the solid phase; pressures, pressure gradients, Darcy velocities for pore water and pore air phases; temperature, temperature gradients, the total heat flux are interpolated as independent variables. The weak form of the governing equations of coupled THM problems in porous media within the element is given on the basis of the Hu–Washizu three‐filed variational principle. The proposed mixed finite element formulation is derived. The non‐linear version of the element formulation is further derived with particular consideration of the THM constitutive model for unsaturated porous media based on the CAP model. The return mapping algorithm for the integration of the rate constitutive equation, the consistent elasto‐plastic tangent modulus matrix and the element tangent stiffness matrix are developed. For geometrical non‐linearity, the co‐rotational formulation approach is utilized. Numerical results demonstrate the capability and the performance of the proposed element in modelling progressive failure characterized by strain localization and the softening behaviours caused by thermal and chemical effects. Copyright © 2005 John Wiley & Sons, Ltd.     

热重质谱联用研究兖州煤的热解行为

利用热重—质谱联用(TG／MS)研究了兖州煤的热解行为、热解气相产物(包括硫分)的在线析出行为以及矿物质对热解气相挥发分逸出的影响；比较了原煤和脱灰煤的TG／MS谱图．结果表明：TG／MS系统在获取煤样热失重信息同时，可以在线监测气相挥发分的选出行为；矿物质对热解过程中H2O，CH4和H2的析出没有影响，但对高温阶段CO和C02的析出有明显的作用．550℃附近硫的逸出产物主要来源于煤中黄铁矿的分解．     

联产电厂中考虑机会成本的热电成本计算

对联产电厂的成本进行经济学上的分摊，不但考虑了燃料消耗、设备折旧及维护费用，还引入了联产电厂机会成本的概念，并按照产品地位系数将机会成本合理地分摊到供热和发电方面，从而改变了热经济学成本只考虑会计成本的计算方法。运用这种方法计算的热、电成本更适合商业运行实际。