Production of biodiesel from waste fryer grease using mixed methanol/ethanol system

Transesterification of waste fryer grease (WFG) containing 5–6 wt.% free fatty acid (FFA) was carried out with methanol, ethanol, and mixtures of methanol/ethanol maintaining the oil to alcohol molar ratio of 1:6, and initially with KOH as a catalyst. Mixtures of methanol and ethanol were used for transesterification in order to use the better solvent property of ethanol and rapid equilibrium using methanol. Formation of soap by reaction of FFA present in WFG with KOH instigated difficulty in the separation of glycerol from biodiesel ester. To untangle this problem, two-stage (acid and alkali catalyzed) method was used for biodiesel synthesis. More than 90% ester was obtained when two-stage method was used compared to ∼ 50% ester in single stage alkaline catalyst. In the case of mixed alcohol, a relatively smaller amount of ethyl esters was formed along with methyl esters. Acid value, viscosity, and cetane number of all the esters prepared from WFG were within the range of the ASTM standard. Esters obtained from WFG showed good performance as a lubricity additive.     

八钢高炉无料钟炉顶的装料制度

以八钢高炉炼铁实践为依据，系统研究和分析了八钢2号和3号高炉炉顶设备装料制度对高炉冶炼的影响。认为高炉操作制度是当前高炉炼铁的主要技术之一，也是影响高炉焦比主要技术经济指标的重要因素。在原燃料和装备水平一定的条件下，合理的操作制度对高炉的技术经济指标起到决定性的作用。     

济钢350m^3高炉高富氧生产技术

分析了济钢350m^3高炉高富氧对产量,理论燃烧温度,炉况顺行状况,焦比和生产效益的影响,高富氧可提高产量,但升高焦比和高炉理论燃烧温度,一定程度上影响高炉顺行,存在富氧效益最大化的适宜富氧率.高炉生产应低富氧高喷煤,根据钢目前的情况,富氧率经2%-3%为宜.     

A Dynamic Dictionary for Priced Information with Application

In this paper we design a dynamic dictionary for the priced information model initiated by Charikar et al. Assume that a set S consisting of n elements is given such that each element has an associated price, a positive real number. The cost of performing an operation on elements of S is a function of their prices. The cost of an algorithm is the sum of the costs of all operations it performs. The objective is to design algorithms which incur low cost. In this model we propose a dynamic dictionary, supporting search, insert and delete, for keys drawn from a linearly ordered set. As an application we show that the dictionary can be used in computing the trapezoidal map of a set of line segments, a fundamental problem in computational geometry.     

长管串井下分离器及尾管举升抽油工艺技术

针对常规防气工艺存在的防气效果不理想、适用范围小、无法使气体影响严重的油井正常生产等问题,研制了长管串井下分离器及尾管举升工艺技术,该工艺以套管和油管间的环形空间为沉降分离体,沉降分离空间大;解决了常规防气工艺适用范围小的工艺难题,并且该装置使混气液转向沉降分离流速降低,利于更细小的气泡分离,使气体分离更彻底,对油气比越高的井效果较明显。经现场对16口井的试验表明,可有效减少气体影响,提高油井泵效。该分离器的试用有效率高,取得了明显的经济效益。     

多掺炼新疆渣油的催化裂化工业生产技术

兰州石化公司以加工新疆原油为主，重油收率高，平均在37％左右，所生产的重油主要靠催化裂化装置来加工，多余部分以低附加值重油出厂。随着涩宁兰天然气工程的逐渐建成，低附加值重油出厂将受到严重威胁，因此，催化裂化装置加工重油显得尤为重要。兰州石化公司炼油厂1.2Mt/a重催装置通过采用先进技术进行改造，使重油掺炼比由41.52%提高到52.20%，提高了10.68个百分点，年多加工重油14.95万t，产品收率达到79.20%以上，能够灵活调节产品结构，创造了良好的经济效益。     

复合地基中优化设计参数的方法

本文给出了复合地基应力比置换率设计的优化方法,讨论了复合地基中应力比的基本概念和影响因素,可供工程应用时参考。     

土壤固化剂无侧限抗压强度试验研究

针对山西省长治市石子河河道处理问题 ,采用固化剂粘土进行了无侧限抗压强度试验 ,并与水泥土进行了比较。发现固化剂 2的无侧限抗压试验强度最佳 ,为工地现场试验及河道综合治理提供了更为有力的理论依据     

舞钢扁钢锭咬边参数的确定

本文根据我公司自产的11.7t及13.34t扁钢锭在4200mm轧机生产过程中,运用正交试验方法,合理应用咬边参数的轧制方案,以此降低金属消耗。此方案使“咬入返回轧制”及“留尾轧制”新技术进一步得到完善,板形更加矩形,使锭一材成材率提高2％左右。     

Modeling of the bulk free radical polymerization up to high conversion—three stage polymerization model. II. Number-average molecular weight and apparent initiator efficiency

The equations for predicting the number-average molecular weight are derived on the basis of the three stage polymerization model (TSPM) in this paper. By applying the equations, a plotting approach is proposed to determine the apparent initiator efficiency defined as f[(α_td+1)/2] and the constant of chain transfer to monomer, where f is the initiator efficiency and α_td denotes the fraction of the termination rate constants by disproportionation. Using the approach to plot the experimental data in the literature, it is found that the chain transfer to monomer can be neglected for both methylmethacrylate (MMA) and styrene (St) polymerizations, but it can exert a significant effect on ethylmethacrylate (EMA) polymerization. In addition, the apparent initiator efficiency is found to be independent of reaction temperature and initiator concentration at each stage. The values of f[(α_td+1)/2] at gel effect stage are slightly reduced as compared with that at low conversion stage for MMA and EMA polymerizations. However, it decreases significantly at gel effect stage for St polymerization. Using the equations derived and the apparent initiator efficiencies obtained from TSPM plots, the number-average molecular weights at different conversions can be predicted. Comparisons show that the agreement between predictions and experimental data is satisfactory.