锥形筛孔塔板流体力学性能的研究

在一个φ500mm的有机玻璃塔中，以空气为物系，测试了普通筛孔塔板和锥形筛孔塔板的干板压降。根据Hughmark-O'Connell关联式计算出流量系数，并对上锥形筛孔塔板干板压降的Hughamrk-O'Connell公式进行修正，得到上锥形筛孔塔板的修正系数β'大于1，其干板压降比普通塔板低20％－30％。在此基础上对普通筛孔塔板和锥形筛孔塔板在气体穿孔时由于流体力不行为不同产生的压降差异进行了分析。     

国外板式塔最新进展与新分离技术开发

激烈的竞争促进了板式塔的迅速发展。对国外一些最新塔板、新的化工过程和蒸馏技术作了简略介绍，其中一些高效塔板的特点体现在降液管的设计上。     

导向浮阀与F1型浮阀的性能研究

导向浮阀塔板是化工生产中应用的一种新型塔板，通过性能测试和对比分析，证明这种板操作优于F1型浮阀塔板。     

烤烟湿润育苗技术研究

对以育苗基质和营养液配方的筛选、肥水管理方式的改进和不同育苗方式比较为主要内容的烤烟湿润育苗技术进行了探讨。结果表明,10号育苗基质配方和2号营养液配方所育烟苗综合素质最高,茎高、茎围适中,根系发达,根系活力强,根茎叶干鲜重最重;育苗肥水管理方式由传统的"一段式"改为"前期浅灌、后期浇施"的"二段式",不仅大大降低了烟农的育苗用工,而且解决了肥水单纯采用浇施,导致基质易板结、出苗率较低、生长不整齐等问题;与漂浮育苗相比,该技术不仅保持了漂浮育苗的优势,同时提高了成苗期烟苗的素质,有效地解决了返苗期偏长的问题。     

导向浮阀塔板和F1型浮阀塔板的比较

应用空气－水系统，在１６００×４００ｍｍ的矩形塔内，对导向浮阀塔板和Ｆ１型浮阀塔板的流体力学进行了试验研究，测定了塔板压降、雾沫夹带和泄漏。应用空气－水－ＣＯ２系统，测定了导向浮阀塔板和Ｆ１型浮阀塔板的效率。试验结果和工业应用表明，导向浮阀塔板的流体力学和传质性能均优于Ｆ１型浮阀塔板     

The impact of heat transfer on Murphree tray efficiency

This work features the experimental determination of heat transfer coefficients and Murphree tray efficiencies on a diabatic (heat-transferring) distillation tray. The present investigation, focussing on the impact of heat transfer on sieve tray performance, is part of a long-term project on heat integrated distillation columns (HIDiC). Heat transfer coefficients and tray efficiencies have been determined experimentally for the methanol/water system in a 150 mm diameter distillation column. The heat-transferring tray was operated in both heating and cooling modes, with heat fluxes up to 50 and 100 kW m⁻², respectively. The experimental data from these diabatic experiments were compared with data obtained from the same column in adiabatic mode and were correlated with the vapour velocity and the heat flux to/from the tray.     

Measuring and predicting head space pressure during retorting of thermally processed foods

Traditional metal cans and glass jars have been the mainstay in thermally processed canned foods for more than a century, but are now sharing shelf space with increasingly popular flexible pouches and semi-rigid trays. These flexible packages lack the strength of metal cans and glass jars, and need greater control of external retort pressure during processing. Increasing internal package pressure without counter pressure causes volumetric expansion, putting excessive strain on package seals that may lead to serious container deformation and compromised seal integrity. The primary objective of this study was to measure internal pressure build-up within a rigid air-tight container (module) filled with various model food systems undergoing a retort process in which internal product temperature and pressure, along with external retort temperature and pressure, were measured and recorded at the same time. The pressure build-up in the module was compared with the external retort pressure to determine the pressure differential that would cause package distortion in the case of a flexible package system. The secondary objective was to develop mathematical models to predict these pressure profiles in response to known internal temperature and initial and boundary conditions for the case of the very simplest of model food systems (pure water and aqueous saline and sucrose solutions), followed by food systems of increasing compositional complexity (green beans in water and sweet peas in water). Results showed that error between measured and predicted pressures ranged from 2% to 4% for water, saline, and green beans, and 7% to 13% for sucrose solution and sweet peas. PRACTICAL APPLICATION: Flexible packages have limited strength, and need more accurate and closer control of retort pressure during processing. The package becomes more flexible as it heats and might expand with increasing internal pressure that may cause serious deformation or rupture if not properly controlled and/or counterbalanced with external retort pressure. This article describes methods for determining exactly what the retort pressure profile will need to be to avoid this problem during retorting, and mathematical models to predict these pressures in response to known internal temperature and initial/boundary conditions.     

黑曲霉B0201固态浅盘生料发酵产单宁酶工艺研究

通过单因素实验,对黑曲霉B0201固态生料浅盘发酵产胞外单宁酶进行了研究.结果表明:最佳发酵工艺为接种龄为30h,接种量为20%,五倍子含量为30%,固液比为1.6∶1,培养温度为0～48h、35℃,48h～96h、25%,96h～120h、30℃,装量为100g,培养期间每隔24h搅拌一下,单位酶活达21.08U.