提高无油润滑活塞使用寿命的研究

通过对活塞环的受力分析以及无油润滑材料的磨损试验研究,从密封结构设计,材料选取等方面提出了提高无油润滑活塞环使用寿命的有效方法。     

影响无油润滑压缩机活塞环工作寿命的分析

本文综述了近几年来推广应用无油润滑技术过程中,因工艺、设备、操作条件变化,影响无油润滑压缩机活塞环使用寿命的各种因素以及采取的措施和方法。     

无油润滑压缩机的复合型填充PTFE导向环活塞环

介绍了以聚对羟基苯甲酸脂（ＰＯＢ）为主的填充聚四氟乙烯（ＰＴＦＥ）复合型导向环活塞环材质特性及使用性能；给出了石油化工工程应用实例。     

L型空压机无油润滑技术改造

将陈旧的Ｌ型有油润滑空压机改造为换代的无油润滑空压机，并采用复合型填充ＰＴＦＥ新材料和带卸荷结构的导向环，不但使用性能与国内同类产品相同，而且导向环和活塞环的使用寿命提高了数倍。     

冰机无油润滑改造

<正> 四0四厂浓硝车间781工段三台冰机,是五十年代苏制设备,属M型卧式双列双缸双作用往复式压缩机,自1977年投产以来,设备显得较为落后,生产成本高。稀硝建成后,综合能     

L型空气压缩机无油润滑改造

将Ｌ型空气压缩机有油润滑结构改造成无油润滑结构,通过改变活塞结构尺寸和采用填充聚四氟乙烯新材料的活塞环及带卸荷载槽结构的导向环,在压缩机工艺指标不变的情况下,取得了有油润滑压缩机无法获得的优良性能。     

活塞式无油润滑压缩机气缸密封件的维修

填充聚四氟乙烯密封件具有很好的自润滑性能,但也有强度低,易于冷流破坏,耐热性差,线胀系数大的缺陷。所以,气缸密封件结构尺寸的合理性,将直接影响气缸的容积效率和密封件的使用寿命,在实践经验总结的基础上,本文阐述了活塞式无油润滑压缩机气缸密封件维修时应注意事项和密封件结构尺寸合理区间的确定。     

L型空压机无油润滑技术改造

将陈旧的Ｌ型有油润滑空压机改造为换代的无油润滑空压机，并采用复合型赶集填充ＰＴＥＥ新材料和带卸荷结构的导向环，不便使用性能与国内同类产品相同，而且导向环和活塞环的使用寿命提高了数倍。     

活塞式压缩机润滑油的选择

介绍了活塞式压缩机润滑方式对润滑油的要求和常用的活塞式压缩机润滑油的分类情况,着重讨论了活塞式压缩机内部润滑油的负荷等级和粘度的选择,及不同介质压缩机润滑油品种的选择方法。     

提高石灰竖窑使用寿命的措施

通过对石灰竖窑采取改进耐火材料材质、改造窑体结构及改进砌筑工艺等措施 ,石灰竖窑的使用寿命由原来的 1年提高到了 3年零 5个月 ,产品的质量、产量和经济效益同时得到提高。     

延长单程套管换热器寿命的工艺方法

通过对温差应力的计算,分析了固态粉末物料锅式真空干燥系统中,套管换热器裂纹原因,并从操作工艺的角度,提出了改进措施。     

V形、W形不锈钢柔性石墨缠绕垫片的结构研究

通过理论分析 ,设计了V形和W形金属缠绕垫片 ,并通过实验证明其性能优越     

延长挤压造粒机环模使用寿命的研究

环模挤压造粒技术设备占地少、工艺简单、产品质量稳定、生产成本低,为国内中小型复混肥企业广泛采用。但是,制粒机的关键组件造粒环模的使用寿命短,却是一大缺陷。 我厂１９９７年３月购进１台ＫＹＷ２５型环模挤压造粒机,４月投产,至年底,共生产成品肥１２８７吨,使用环模２４只,每只环模平均生产肥料约５４吨。按当年市价,每吨成品摊环模费用２３．３０元。为降低成本,提高环模使用寿命,对环模的预处理进行研究,确定了环模的最佳预处理方案,现介绍如下。１造粒环模简述 环模挤压造粒是造粒环模主动旋转,带动其内环的一对辊…     

Kinetic studies on the esterification of free fatty acids in jatropha oil

Kinetic studies have been carried out on the esterification of free fatty acids (FFAs) in jatropha oil with methanol in the presence of sulphuric acid catalyst at 5 and 10 wt% concentrations relative to free fatty acids (0.4–0.8 wt% relative to oil) and methanol–FFA mole ratios ranging from 20:1 to 80:1. It has been found that a 60:1 methanol–FFA mole ratio and 5 wt% catalyst at 60°C and 500 rpm or above provided a final acid value lower than 1 mg KOH/g oil within 60 min. A kinetic model has been proposed with second‐order kinetics for both the forward and backward reactions. The effect of temperature on the reaction rate constants and equilibrium constant has been determined using Arrhenius and von't Hoff equations, respectively. The heat of reaction was found to be ?11.102 kJ/mol.     

Effect of lubrication on the distribution of force between spherical agglomerates during compression

We employ the carbon paper technique to aid the understanding of in die force and spatial distributions, upon compression of approximately 1 mm sized spherical agglomerates (pellets) of microcrystalline cellulose (MCC). The aim in this study was to test for the effect of lubricant film on force and spatial distributions. Pellets of MCC were formed via granulation and extrusion/spheronisation. Investigation of pellet bed compression was performed on a materials tester. Prior to compression studies the pellets were characterised for bulk density, size and deformability. Two pellet types were investigated; MCC and MCC lubricated with magnesium stearate. The carbon paper technique relies upon carbon paper as the medium for transferring imprints from compressed pellets onto photo quality paper. The digitised images of these imprints form the basis of analysis through the use of image processing software. Using the carbon paper technique within the range of 10-30 MPa indicates that lubrication does not have a significant effect on the distribution of forces between spherical agglomerates during uniaxial compression. Spatial analysis of the imprints revealed that the lubricated pellets exhibited a higher packing order than the unlubricated ones at low applied pressures (10 and 20 MPa), a difference that could not be observed at 30 MPa. Hence interparticle friction and/or cohesion appear to influence the initial particle rearrangement, whereas confinement is suggested to dominate at higher pressures.     

Effects of free fatty acids on oxidative stability of vegetable oil

The effect of free fatty acid (FFA) content on the susceptibility to thermooxidative degeneration of vegetable oils was determined by Rancimat analysis. A prooxidant effect of FFA was observed in all filtered oils, independently of lipidic substrate and of its state of hydrolytic and oxidative alteration. The intensity of this effect was related to FFA concentration, but regression analysis of the experimental data did not show a general correlation law between FFA concentration and induction time (I _t). Different results were obtained for freshly processed virgin olive oils, characterized by postpressing natural suspension-dispersion: opposite behavior was observed of FFA content as regards oxidative stability, depending on the presence of suspended-dispersed material. This fact is of interest because the dispersed particles play a double stabilizing effect on both oxidative and hydrolytic degradation. These results showed that avoidance of oil filtration is highly desirable to extend olive oil’s shelf life.     

Influence of free fatty acid content of coconut oil on deposit and performance of plant oil pressure stoves

In tropical and subtropical countries, utilization of unprocessed plant oil or used frying oil as household cooking fuel promises to be a competitive alternative to well known fuels like wood and kerosene. However, the use of unprocessed plant oil in plant oil pressure stoves leads to the formation of deposits inside the vaporizer, which have to be removed from time to assure a proper operation of the plant oil pressure stove.Therefore, the objective of this study was to investigate the effect of free fatty acid content of coconut oil on performance and deposit formation in plant oil pressure stoves. Test fuels with different levels of free fatty acid content were prepared by aerating the coconut oil with dry air (5.04 l O₂/kg h) at a temperature of 85 °C. Experiments were performed with the plant oil pressure stove ’Protos’ (BSH Bosch und Siemens Hausgeräte GmbH).As a result, 0.15 g of deposits per kg of consumed oil was found for fresh coconut oil with free fatty acid content of 0.03%, which served as control. Aged oil with a free fatty acid content of 23.1% resulted in 6.48 g deposits per kg of consumed test fuel. Conradson carbon residue CCR of 0.18% was low for control and increased to 0.82% for aged oil. Specific fuel consumption was in a range between 0.284 and 0.304 kg/h without significant differences between the fuels. Performance of the plant oil pressure stove was not affected by the amount of free fatty acids in the plant oil. However, lower heating value decreased from initial 35 MJ/kg for control to 30 MJ/kg for aged fuel, and as consequence power output from plant oil pressure stove decreased. Therefore, plant oils with free fatty acid content below 5%, which is equivalent to an acid value of 10 mg KOH/g, are recommended as fuels for plant oil pressure stoves.     

Enzymatic epoxidation of soybean oil methyl esters in the presence of free fatty acids

Epoxides of soybean oil methyl esters (SMEs) are biodegradable, non‐toxic, and renewable epoxy plasticizers. The objective of the present work was to investigate the effects of free fatty acids on the enzymatic epoxidation of SMEs. The results showed that the epoxidation of SMEs depended on the type of the added free fatty acid. For saturated (≤C_18:0) and monounsaturated free fatty acids, the epoxy oxygen group content (EOC) of SMEs increased with increasing carbon chain length of free fatty acids; for branched‐chain unsaturated free fatty acids, the EOC of SMEs decreased in the presence of hydroxyl group (OH) and hydroperoxide (OOH) of free fatty acids; the EOC of SMEs decreased with increasing number of double bonds of free fatty acids. The maximum EOC and the initial epoxidization rate (V₀) linearly decreased with increasing peroxide value of SMEs. The highest EOC (6.87 ± 0.3%) of SMEs was obtained using behenic acid as reaction material, which was similar with that of stearic acid (EOC 6.75 ± 0.2%).