直吹式锅炉中双进双出磨煤机典型故障分析

简要介绍了BBD4060型双进双出钢球磨煤机的原理及其结构特点,针对磨煤机在燃用贫煤时风粉温度过低导致锅炉频繁灭火的问题进行了深入分析并提出了改进措施,效果明显;分析了导致分离器频频堵塞的原因并提出了切实可行的改造办法,圆满解决了问题;针对磨煤机启停过程中一次风关断挡板变形卡涩、开启困难的问题,从检修及运行调整两个方面提出了改进方法,明显改善了一次风关断挡板的运行状态,大大降低了操作过程中检修及运行人员的劳动强度。     

双进双出磨煤机正压直吹式制粉系统异常分析

黔东电厂600MW锅炉机组在调试期间,双进双出磨煤机正压直吹式制粉系统不同程度地出现了原煤仓空仓,给煤机断煤,给煤机上下闸板卡涩、不灵活,给煤机及给煤机清扫电机频繁故障等问题,甚至出现了给煤机内超温和烧损导致制粉系统异常的情况。为此,分析了制粉系统各种异常现象的原因、特点和危害,提出并采取了相应的技术措施,确保了锅炉机组安全经济运行。     

BBD3854型双进双出磨煤机调试

介绍了BBD3854型双进双出磨煤机的特点和在株洲电厂的运行情况,重点介绍了该磨煤机及其料位测量系统的调试过程、调试过程出现的主要问题及处理方法。     

基于响应面法的废石-铜渣掺和比充填强度影响试验

充填料浆配比与强度在矿山准确充填过程中起决定性作用,运用两种骨料堆积密实度模型分析废石-铜渣混合比例以得出混合骨料最佳掺和比,采用BBD响应面法,对废石-铜渣进行膏体配比设计,建立了各龄期的充填体强度回归模型,研究了料浆质量浓度、水泥添加量、废石-铜渣掺和比单因素及其交互作用对不同龄期充填体强度的影响。结果表明：料浆质量浓度和废石-铜渣掺和比的交互作用对充填体强度初期形成起支撑作用,水泥添加量和废石-铜渣掺和比交互作用对中期充填体强度影响显著,料浆质量浓度和水泥添加量交互作用对后期充填体强度增长起决定性作用。建立充填物料多目标函数模型对废石-铜渣膏体配比进行优化,满足矿山生产要求。在一定程度上为矿山多元骨料的应用提供了理论指导,同时有助于矿冶固废铜渣的综合利用。     

Parameter optimization for the oxidative coupling of methane in a fixed bed reactor by combination of response surface methodology and computational fluid dynamics

A resource and time saving method is introduced for optimizing fixed bed reactors by the combination of response surface methodology (RSM) and CFD simulation. This is demonstrated for the oxidative coupling of methane (OCM) based on the reaction kinetics by Stansch et al. (1997). Firstly, a parameter screening is performed to identify the power factors modified reaction time, heating temperature and CH₄ to O₂ ratio. Secondly, utilizing Central Composite Design, meta models for the most interesting responses are developed, i.e. C₂ selectivity and yield as well as CH₄ conversion. The statistical models describe the characteristics of the responses over a wide range. Thirdly, an optimization of C₂ yield is carried out using RSM. The maximum is detected to be approx. 14% and validated by three dimensional CFD simulations. In the investigated parameter space the optimized parameter conditions are found for a feed composition of 20% nitrogen, 26.7% oxygen, 53.3% methane (CH₄ to O₂ ratio of 2), a modified reaction time of 61 kg s/m³ and a heating temperature of 801.5 °C.     

An Efficient Adaptive Sequential Methodology for Expensive Response Surface Optimization

The preset response surface methodology (RSM) designs are commonly used in a wide range of process and design optimization applications. Although they offer ease of implementation and good performance, they are not sufficiently adaptive to reduce the required number of experiments and thus are not cost effective for applications with high cost of experimentation. We propose an efficient adaptive sequential methodology based on optimal design and experiments ranking for response surface optimization (O‐ASRSM) for industrial experiments with high experimentation cost, limited experimental resources, and requiring high design optimization performance. The proposed approach combines the concepts from optimal design of experiments, nonlinear optimization, and RSM. By using the information gained from the previous experiments, O‐ASRSM designs the subsequent experiment by simultaneously reducing the region of interest and by identifying factor combinations for new experiments. Given a given response target, O‐ASRSM identifies the input factor combination in less number of experiments than the classical single‐shot RSM designs. We conducted extensive simulated experiments involving quadratic and nonlinear response functions. The results show that the O‐ASRSM method outperforms the popular central composite design, the Box–Behnken design, and the optimal designs and is competitive with other sequential response surface methods in the literature. Furthermore, results indicate that O‐ASRSM's performance is robust with respect to the increasing number of factors. Copyright © 2012 John Wiley & Sons, Ltd.     

配双进双出钢球磨煤机燃烧系统调试和运行研究

针对配双进双出钢球磨煤机四角切圆燃烧系统的特点,提出了优化调试和运行方法并付诸实施,取得了明显的经济和社会效益。     

PP生产中工况条件对催化剂活性多因素影响的响应面模型

利用基于Box Behnken设计(BBD)的响应面方法,设计出5因素3水平(L4635)实验方案,就聚合温度(T)、聚合压力(p)、丙烯质量流量(qP)、催化剂用量(qC)、H2体积分数(φH)5个因素对丙烯聚合过程中催化剂活性的影响进行分析,得到丙烯聚合工艺条件与催化剂活性间的响应面模型,并使用不同方法对该模型进行方差及回归分析。结果显示,在聚丙烯生产中,增加T、p、qP和φH可以提高催化剂活性,而qC过多对提高催化剂活性不利;5因素对催化剂活性影响的显著性大小依次为qP、T、p、qC、φH。该模型对降低聚丙烯中灰分、提高产品质量及降低原料消耗、降低生产成本、增加经济效益均有重要意义。     

基于BDD故障树的雨弹使用可靠性评估

建立了基于工作任务模式的雨弹系统可靠性故障树模型,提出了基于BDD故障树的雨弹系统使用可靠度评估方法,并将此方法应用于BL-1A型雨弹的可靠性评估。理论分析评估结果与该型雨弹可靠性鉴定试验结果的相对误差为ε=5.526 797×10-4,二者具有很好的一致性,表明该方法能有效指导雨弹使用可靠性的分析与评估。更多还原     

超声波辅助纤维素酶提取牡丹籽饼中多糖及其清除自由基活性研究

采用超声波辅助纤维素酶提取牡丹籽饼中多糖。在单因素试验的基础上,采用PB设计对影响多糖提取量的9个因素(pH、加酶量、酶解时间、酶解温度、超声时间、超声功率、超声温度、液料比、粒度)进行显著性分析。通过BBD响应面法优化最佳提取工艺条件。采用清除DPPH自由基活性评价牡丹籽饼中多糖的抗氧化能力。结果表明,牡丹籽饼中多糖的最佳提取工艺条件为:加酶量0.45%,酶解时间60 min,酶解温度45℃,pH 4.5,超声时间19 min,超声功率300 W,超声温度40℃,液料比19∶1,粒度60目。在最佳工艺条件下,牡丹籽饼中多糖提取量为196.87 mg/g。牡丹籽多糖具有一定DPPH自由基清除能力,但弱于V_C,其IC_(50)值为31.19μg/m L。