再造烟丝形态优选及在卷烟中的应用初探

通过对卷烟烟丝的分析及对不同长度樽造烟丝填充值的测定,优选出了比较理想的再造烟丝,其长度为20mm、宽度为0．9mm。该再造烟丝在卷烟工艺的烘丝之后、加香之前与叶丝进行掺配,提高了再造烟丝在卷烟中的混合均匀性,该种方法具有改善再造烟叶成丝质量、提升卷烟开发灵活性、稳定卷烟品质的重要意义。     

制丝关键工艺参数对杂环化合物的影响

采用气相色谱-质谱联用仪检测了不同制丝关键工艺参数加工后的烟丝中的杂环化合物2-乙酰基吡咯和2-乙酰基呋喃的含量,结果显示:真空蒸湿温度、一周期抽空温度、超回蒸汽喷射比例、烘丝热风风量对2-乙酰基吡咯和2-乙酰基呋喃含量的加和值有显著影响,在试验范围内,随真空回潮蒸湿温度的增加,制叶丝纯丝中2-乙酰基呋喃和2-乙酰基吡咯含量的加和值先下降,当真空回潮蒸湿温度大于56℃后出现增加趋势;随真空回潮一周期抽空温度的增加,制叶丝纯丝2-乙酰基呋喃和2-乙酰基吡咯含量的加和值先升高,当一周期抽空温度大于10℃后出现下降趋势;随着超回蒸汽喷射比例的增加,制叶丝纯丝中2-乙酰基呋喃和2-乙酰基吡咯含量的加和值先升高,当超回蒸汽喷射比例大于6.5kg/100kg后有下降趋势;制叶丝纯丝中2-乙酰基呋喃和2-乙酰基吡咯含量的加和值则随着烘丝热风风量的增加而升高,当烘丝热风风量大于2400m3/h后出现下降趋势。     

大型低温多效蒸馏海水淡化装置中试研究

基于低温多效蒸馏海水淡化中试装置,研究了工作蒸汽流量、TVC抽汽温度、物料水流量等运行操作条件以及换热管倾斜布置对装置整体性能的影响.结果表明:调整工作蒸汽流量是控制装置淡水产量的主要手段,装置的淡水产量随工作蒸汽流量的增加而增大;TVC抽汽温度升高有利于提高淡水产量和造水比;装置的淡水产量和造水比均随物料水流量的增加呈现下降的趋势,但下降幅度不大;在5‰的斜率内换热管倾斜布置还是水平布置对淡水产量几乎没有影响.     

过热蒸汽间歇干燥酒精糟研究

以高湿物料酒精糟为研究对象,进行了过热蒸汽间歇干燥实验研究。利用自行设计的间歇干燥实验台,酒精糟的初始含水质量分数为66.7%,研究了不同实验条件对干燥速率的影响。结果表明:随着干燥介质温度的升高,干燥速率明显加快;被烘物料质量越少,烘干时间越短;随着物料颗粒直径的减小,恒速段的干燥速率基本不变,而降速段的干燥速率明显增加;过热蒸汽质量流量越大,干燥速率越高。因此随着蒸汽过热度的升高、质量流量的增大,过热蒸汽干燥速率加快,干燥效率越高;随着进料质量的增加、颗粒直径的增大,过热蒸汽干燥速率却有所降低。     

烟丝输送皮带导流匀料装置的研制及应用

为解决卷烟工厂制丝生产线掺配工序物料汇总主通道皮带上烟丝实物分布、混合不均匀的问题,设计了一种可拆卸、不堵料、不造碎的纯机械式装置,能够对输送皮带上的烟丝进行修整、导流和有效匀料。结果表明,使用该导流匀料装置后,在4400 kg/h和2600 kg/h的叶丝流量下,物料漏掺(断点)次数减少,由原来的3～4次变为小于等于1次;物料边缘凹凸情况明显改善,物料宽度极差,由原来的47～39 cm变为小于24 cm;物料高低不平现象明显改善,物料高度极差,由原来的20～18 cm变为小于等于15 cm。     

天然气制氢装置工艺安全分析

利用危险与可操作性分析的方法对天然气制氢装置中转化工序进行工艺安全分析。分别对反应物的流量、温度、压力、流量比例等工艺参数发生偏离时,可能发生的问题以及如何采取措施避免事故发生。通过分析发现的问题有安全阀、自动放空阀增加底阀;工艺蒸汽系统增加止回阀,防止气体出现回流现象;必须加备用引风机或蒸汽引射,防止紧急停车时炉顶火焰喷出伤人,对这些问题需要加以改进。     

吡丙醚系列悬浮剂自动化加工工艺研究

研究釡内剪切机形式、在线剪切、砂磨机锆珠填充率、砂磨机物料流量等参数对吡丙醚系列悬浮剂的粒径影响。结果表明,高剪切有助于快速降低粒径,在线剪切有助于改善粒径分布范围,达到均质的目的。研究吡丙醚系列悬浮剂的最佳锆珠填充率及砂磨物料流量,确定吡丙醚系列悬浮剂的最佳生产工艺条件。     

压延加工过程中λ参数的工程意义

通过对辊筒上压延过程的流变分析引入无量纲体积流量参数λ,详细讨论了参数λ与压延过程工艺参数及被加工物料粘弹性的关系,经计算后,得知λ值直接影响辊筒间物料流动驻点X’＊的所在位置。加料口位置为X’,在X’x’＊区域,物料流动平稳,有益于物料平整贴合、压片、压型等工艺操作。然后介绍了确定参数λ的几种方法。     

复混肥装置干燥工序的优化改造

通过对干燥工序在不同工况下热平衡模拟计算对比分析，结合实际生产情况，指出造粒物料湿含量的波动是影响生产平稳运行的核心问题，通过工艺优化改进，采用变频调节造粒液泵的输出流量，烘干机进口增设大流量低压头鼓风机，变频调节出口引风机来提高干燥操作的弹性空间，实现装置长周期、高负荷地稳定运行。     

制丝关键工艺参数对羟基化合物的影响研究

不饱和羟基化合物有增加烟草本香,改善香气质提高烟气浓度和丰富性等作用,大部分产生于制丝加工过程中的降解。通过均匀化试验设计,在一定范围内改变关键制丝工艺参数,研究了制丝加工过程中关键工艺参数对巨豆三烯酮和大马士酮相对含量的影响。结果表明,超回蒸汽喷射比例、真空蒸湿温度、一周期抽空温度是影响纯丝中巨豆三烯酮含量的关键工艺参数,在试验范围内,随着超回蒸汽喷射比例的增加,制叶丝纯丝中巨豆三烯酮的相对含量呈上升趋势;随着真空蒸湿温度的增加,制叶丝纯丝中巨豆三烯酮质量分数先升高后降低;随真空回潮抽空温度的增加,制叶丝纯丝中巨豆三烯酮质量分数呈上升趋势。一周期抽空温度、真空蒸湿温度、超回蒸汽喷射比例、超回热风风量是影响纯丝中大马士酮含量的关键工艺参数,在试验范围内,随着一周期抽空温度的增加,制叶丝纯丝中大马士酮的含量呈上升趋势;随真空回潮蒸湿温度的增加,制叶丝纯丝中大马士酮质量分数呈抛物线趋势;随着超回蒸汽喷射比例的增加,制叶丝纯丝中大马士酮质量分数先减少后增加;随着超回热风风量的增加,制叶丝纯丝中大马士酮质量分数先增加后减少。     

滚筒干燥器内丝状物料的传热传质特性研究

干燥涉及众多生产领域,卷烟加工过程中存在干燥环节,滚筒烘丝机是用于干燥烟丝的主要设备。在滚筒烘丝机内,烟丝与周围环境进行热质交换,不同的运行控制条件,将直接影响烟丝的品质。由于干燥过程受众多因素的影响,至今烟草加工企业对烘丝机内部烟丝的传热传质特性缺乏深层次的认识,不利于烟丝品质的提高。针对上述背景,本文基于传热传质学、流体力学、多相流动等相关理论,通过计算机数值模拟方法,建立并求解滚筒内的传热传质数学模型,获得不同操作条件下烟丝温度、含水率变化的详细信息,并将所得结果与实际生产数据相验证。研究结果表明,烟丝与气流逆流流动条件下,干燥过程存在三个阶段：预热段、恒速段、降速段,烟丝含水率先升后降,烟丝温度经历先升高、后降低、再升高的过程;顺流流动条件下,干燥过程存在两个阶段：预热段与恒速段,烟丝含水率沿程单调下降,烟丝温度在预热段急剧上升,在恒速段平缓上升。     

Fast drying of cut tobacco in drop tube reactor and its effect on petroleum ether tobacco extracts

Entrained flow drying is an important fast drying tool in tobacco industry. This study used a drop tube reactor (DTR) as an entrained flow dryer to investigate drying process of flue-cured cut tobacco. Lab-scale cold and hot DTRs were set up to obtain drying kinetics for three types of cut tobacco using different drying gases and temperatures. The effective diffusion coefficients of cut tobacco in DTRs were compared with those in a general cylinder dryer. Moreover, the effects of different drying gases and temperatures on petroleum ether extract content were investigated. The results showed that the effective diffusion coefficients of cut tobacco in the DTRs were between 2.296?×?10^?8 and 8–6.244?×?10^?8?m²/s, which are two orders of magnitude higher than those in the cylinder dryer. Compared to hot air as a drying medium, superheated steam improved the effective diffusion coefficient of cut tobacco. The petroleum ether tobacco extract had a higher retention ratio when the superheated steam was used in the DTRs. An increase in the drying temperature resulted in a lower retention of the petroleum ether tobacco extract.     

复烤干燥工艺参数对烟叶pH值的影响

研究了打叶复烤干燥过程及工艺条件对烟叶p H值的影响。选择干燥一区至三区温度、排潮风门开度、新风风门开度等9个因素,采用均匀设计法设置了10种不同的工艺参数组合,对云南玉溪K326品种B2F、C3F混打烟叶进行处理,测定干燥前、后样品的p H值。结果表明,干燥后烟叶p H值呈现降低趋势,变化幅度在0.183%~0.927%之间;干燥工艺条件对p H值的变化幅度有显著影响,其中干燥一区、二区、三区新风风门开度,干燥二区、三区温度是影响p H值变化的重要因素。     

优化烘丝简控制模式降低烟丝干头量

针对烘丝过程中出现的干头干尾量偏大问题,分析烘丝机运行方式和控制模式,优化改进烘丝控制模式,使干头干尾量从60kg降低至35kg。     

Drying kinetics study of irregular fibril materials in a “differential” laboratory rotary dryer: Case study for cut tobacco

Rotary dryers are commonly used in the modern large-scale tobacco drying industry that consumes huge amounts of energy. In fact, rotary dryers are commonly used in chemical industry in general. It is difficult to investigate the drying behavior at industrial scale. A “differential” laboratory rotary dryer was therefore designed and tested. The large diameter of the industrial dryer was preserved, but the width was a section of the industrial dryer. The drying characteristics of cut tobacco from top leaves and bottom leaves with initial moisture contents (22.5?±?1.0% on the wet basis) were studied in the “differential” dryer at air temperatures of 65, 85, 105, 125, and 145°C, respectively. The results show that increasing drying temperature accelerated the drying process, whereas the surface temperatures of the cut tobacco samples stayed in the temperature range of 48–71°C when their moisture contents were reduced to 12.0?±?1.0% (wb). This 12.0% (wb) was required by commercial operations. Uniquely, the drying kinetics was captured using the reaction engineering approach (REA). Although different settings were applied, the model can be used to describe all the data well. The unique relationship between the normalized activation energy and the moisture content is approximated which is independent of the drying air temperature and the tobacco origin. The different drying behaviors for the cut tobacco from top leaves and bottom leaves can be attributed to their different equilibrium isotherms. Through controlling the drying time as predicted by REA model, the outlet moisture contents of cut tobacco from top leaves dried at 95°C/RH0.034/320?s and 115°C/RH0.017/250?s were shown to be 12.3 and 11.8% (wb), with the relative deviations of 2.5 and 1.7%, respectively, and these were within the industrial permissible range.     

Effect of two-stage dehydration on retention of characteristic flavor components of flue-cured tobacco in rotary dryer

Two-stage dehydration method of flue-cured tobacco in rotary dryer was experimentally evaluated and compared to the single-stage dehydration process. The characteristic flavor components in dried cut tobacco, including major Maillard reaction compounds and carotenoid degradation products, as well as drying rate were analyzed for different two-stage dehydration operations. The results showed that both the pre-drying temperature and intermediate moisture content had a significant effect on the overall drying rate of cut tobacco during two-stage drying. On the other hand, the retention of characteristic flavor components in tobacco, especially Maillard reaction compounds retention, was influenced significantly by the final drying temperature as well as intermediate moisture content. The 10°C increase in the final drying temperature from 100 to 110°C reduced the retentions of Maillard reaction compounds and carotenoid degradation products by 14.5 and 9.4%, respectively. Change of intermediate moisture contents from 19 to 15% reduced the Maillard reaction compounds retention by 14.7%. Given the consideration of characteristic flavor components’ retention and drying process efficiency, two-stage dehydration of cut tobacco in rotary dryer could reach a better performance as compared with the single-stage dehydration. The cylinder-wall temperature combination of 140/100°C with the 17% intermediate moisture content could be used as the optimal two-stage condition for the investigated flue-cured tobacco.     

Experimental and Numerical Investigation of the Heat and Mass Transfer for Cut Tobacco During Two-Stage Convective Drying

In this article, a two-stage convective drying strategy was presented for dehydration of flue-cured tobacco. In order to develop the multistage drying method of tobacco, two-stage drying as well as traditional single-stage drying of cut tobacco was experimentally evaluated and accurately simulated by proposed heat and mass transfer models. The experiments were performed in a dual fixed bed dryer. Different air temperature combinations of 120°C/90°C, 110°C/80°C, and 100°C/70°C were employed during two-stage drying. The drying rate and temperature variations of cut tobacco were investigated. The results showed that the average drying rates during two-stage drying were nearly 50% higher than those obtained from lower-temperature single-stage drying. On the other hand, the two-stage drying method, which used high air temperature for the early period and low temperature for the late period, could reduce the exposure of tobacco to high temperature due to the low final temperature of the dried sample. The temperature and moisture evolution of cut tobacco at different air temperature combinations were consistent with simulation results by developed heat and mass transfer models. This indicated that the models had a good prediction precision for two-stage drying of cut tobacco. The model predictions can be useful for the design of a feasible two-stage drying process for flue-cured tobacco.     

“三丝”掺配对主流烟气游离烟碱/烟碱比值的影响和趋势分析

通过正交设计,研究了三丝掺配(薄片、梗丝、膨胀烟丝与烟丝的掺配)对主流烟气中游离烟碱/烟碱比值的影响。3种掺配原料的影响效应大小为:梗丝效应≈薄片效应膨胀烟丝效应,无显著交互效应。对不同三丝掺配比例下的趋势分析发现,游离烟碱/烟碱比值随梗丝、薄片掺配量增加而增加,且在一定的掺配量范围内呈现变化趋势;游离烟碱/烟碱比值随膨胀烟丝掺配量比例增加而降低,但在少量的掺配量范围内变化趋势不是特别明显。     

烟草干燥系统热管换热器的结构确定

简介了烟草干燥系统里热管换热器的热效率提高的意义和必要性。以烟草干燥系统工艺换热器的设计为背景,选择热管换热器结构,进行了热力计算、压力降计算和结构设计计算。热管换热器的设计方案可以为烟草干燥系统工艺换热器的更新改造提供一种新的思路。     

Drying Characteristic of Porous Ceramic Microspheres in a Microwave Heated Fluidised Bed

This paper presents drying characteristics of both water and nitrate salt solution (simulated waste) impregnated ceramic microspheres in a pilot‐scale (10 kg), batch fluidised bed drier heated with microwave energy, under isothermal bed conditions. For comparison, some constant microwave power experiments with water saturated microspheres were also conducted. The effects of bed temperature, fluidising gas flow rates and initial moisture content on drying kinetics were examined. For a given initial moisture and gas flow rate, the total microwave energy consumption for both isothermal bed and constant power level experiments was found to be approximately the same. The decline in drying rates in the presence of nitrate salts was attributed to a decrease in the effective diffusivity resulting from changes in structural properties of salt solution impregnated powders. The use of fluidised bed coupled with microwave heating produced controlled drying of 10 kg batches of simulated waste loaded ceramic powders without any significant agglomeration or coating.