风选工艺参数对梗丝结构的影响

为降低梗丝在后加工工序中的造碎率,对风选后输送风速和烘后梗丝含水率两个主要参数变化对梗丝结构的影响进行了测试。结果表明:①风选后的输送风速越高,梗丝的造碎率越大;②烘后梗丝含水率越高,梗丝造碎率越低;③在实际生产中,烘后梗丝含水率宜控制在13 5%左右;风选后的输送风速应在保证风分箱风选效果良好的前提下尽量调低。     

LEGG制梗线梗丝膨胀工艺参数设计

通过对芜湖卷烟厂ＬＥＧＧ制梗线梗丝膨胀环节的主要工艺参数进行测试分析与研究，设计了一套较为合理的梗丝膨胀工艺条件。实验认为：梗丝宽度相对标准偏差越小，其填充值越高；当热风温度为１１３℃、超级回潮温度为１００℃、梗丝含水率为３７．５３％时，其烘后梗丝填充值达到最高。在滚筒式烘丝机干燥烟梗过程中，应尽可能提高热风温度、降低筒壁温度，适当提高滚筒转速、增加热风风量、减少排湿风量。对ＬＥＧＧ制梗线存在的问题提出了改进建议。     

提高SH83型隧道式梗丝干燥机热风温度的稳定性

针对梗丝生产过程中SH83型隧道式烘丝机烘后出口水分波动的问题进行分析,得出热交换器供给蒸汽压力不稳定、热风温度波动直接影响烘梗丝机出口水分的结论。通过在热交换器供汽主蒸汽管路中增加减压阀和根据设计的尺寸购买更换热交换器的方法,改善烘梗丝机的性能,提高梗丝烘后出口水分的稳定性,保证产品的内在质量。     

FBD双回路控制系统的设计应用

梗丝干燥流化床FBD(Fluid Bed Dryer)含水率控制系统中3个区的温度控制是纯滞后大惯性环节,存在系统响应速度慢、受到扰动时波动大、达到稳定时间长等问题.为此,设计了以风量控制为主、温度控制为辅的双回路含水率控制方式,含水率波动较小时采用风量调节,含水率偏差较大时采用热风温度调节,有效改善了"干头"和"干尾"时间长、纯温度控制系统滞后大、易扰动的现象,加快了系统的响应速度,提高了系统的稳定性.梗丝含水率的平均合格率由改造前的83.88%提高到95.56%,保证了梗丝的工艺质量.     

节能型梗丝低速气流干燥机研发与应用评价

针对现有梗丝干燥设备存在的缺陷和不足,研究开发了低速节能型梗丝气流干燥机。该设备采用文氏管和干燥器分开设置以提高热交换效率、干燥系统通过悬浮干燥技术提高了热风与梗丝的传热传质系数,并与传统的隧道式梗丝干燥机进行了应用比较。结果表明:①整丝率提高5个百分点,碎丝率降低百分比为39.6%;②干燥出口梗丝含水率极差由2.1%降低到0.61%,卷烟样品的感官质量平均提高了0.5分;③加工单位质量梗丝能耗平均降低了34.63%。     

梗丝超级回潮机含水率控制系统的改进

为解决梗丝超级回潮机在生产过程中出现加水不均匀、梗丝含水率波动大等问题,对回潮机的增湿回路及控制模式进行了改进。在补偿蒸汽回路中增加薄膜阀实现精确自动控制,并采用级联方式与加水回路共同对梗丝含水率进行调节。当补偿蒸汽含冷凝水过多或梗丝来料含水率偏大时,只采用补偿蒸汽回路实现梗丝回潮;当补偿蒸汽回路对含水率调节无法达到要求时,采用级联方式由加水回路进行加水调节。结果表明:改进后梗丝超级回潮出口含水率为35.94%,满足了工艺生产要求。标准偏差SD降低0.14百分点,过程能力指数Cpk提高0.59,西格玛水平提高1.54,改善了系统稳态性能,实现了梗丝含水率的精确控制。     

制丝线梗丝风送系统改造

针对梗丝经过原有风送系统输送后造碎大、整丝率低的状况及其产生原因,对梗丝风送系统进行了降低管道风速等系列设备技术改进,并采取提高梗丝膨胀后含水率控制标准等措施。改造后提高了风送后梗丝的整丝率,减少了梗丝的造碎。     

模糊-PID控制在梗丝流化床中的应用

梗丝流化床干燥系统存在的主要问题是出口梗丝含水率波动大、不稳定,通过对干头、湿头产生原因的分析,设计了基于PLC的模糊-PID控制方案和二维模糊控制器.应用结果显示,运用模糊-PID控制方法对梗丝流化干燥系统进行改造,系统的动态性能指标明显改善,抑制了温度滞后性对控制系统的影响,增强了控制系统的稳定性能,改善了梗丝的内在质量.每批次产品的干头、湿头梗丝明显减少,梗丝的月合格率由原来的60.3%提高到92.0%以上.     

膨胀梗丝烘丝前的最佳含水率

梗丝膨胀的机理是基于木质纤维具有湿胀干缩的物理性质.膨胀梗丝烘丝前,梗丝含水率选用何值为宜,是人们关心的问题.本文通过隧道式喷射蒸汽膨胀工艺试验研究,找出最佳含水率为40%～42%.     

滚筒-气流式烘丝机的设计应用

由于气流式和滚筒式烘丝机存在烘后叶丝含水率波动大、叶丝结团和"干头干尾"等问题,结合两种烘丝机的技术优势,设计了滚筒-气流式烘丝机。该设备主要由进出料气锁、干燥滚筒、燃烧炉、主工艺风机等组成,采用气流烘丝原理,即利用含一定量蒸汽的热风在滚筒内与叶丝均匀接触,进行热量对流交换,完成叶丝脱水干燥。通过调节烘丝温度、烘丝时间、水流量和排潮量,实现对烘后叶丝含水率的精确控制。应用效果表明:①烘后叶丝含水率均匀、稳定,含水率偏差±0.5%,填充值≥4.3 cm3/g,烟丝颜色、形态好,保持了烟草本香。②设备工艺参数调节范围宽,满足了中式卷烟分组加工和精细化加工需求。③设备结构简单,滚筒筒体不会出现泄漏问题,减少了设备维护工作量,降低了工人劳动强度和设备维修成本。     

烘丝工艺参数对卷烟感官质量的影响

为研究制丝工序工艺参数变化对卷烟感官质量和化学成分的影响趋势,按照“卷烟制丝生产线工序质量评价”的要求和方法,对烘丝过程中的滚筒转速、热风温度、热风风门开度和排潮风门开度等工艺参数对卷烟感官质量的影响进行了试验。结果表明:①较高的滚筒转速、热风温度、排潮风门开度有利于卷烟香气的透发和提高,但不利于烟气特性和口感特性的改善;②较低或较高的热风风门开度都不利于卷烟香气特性的改善;③随滚筒转速、热风温度和热风风门开度的增大,烟丝中的挥发性有机酸和非挥发性有机酸总量逐渐降低,TSNA含量逐渐增加;④随排潮风门开度的增大,烟丝中的有机酸总量逐渐增加,TSNA含量逐渐降低。     

滚筒烘丝机控制方法的改进与对比分析

为了解决目前滚筒烘丝机中以筒壁温度控制出口烟丝含水率对产品质量稳定性造成一定影响的问题,对滚筒式烘丝机叶丝干燥去湿控制方法进行了改进:在现有筒壁温度控制模式的基础上增设一套以调节入口热风风量来实现出口含水率自动控制的热风风量控制模式,并且对两种控制模式进行了试验对比,结果表明:①采用热风风量控制模式,出口叶丝含水率和出口叶丝温度的稳定性较好,且含水率和温度的波动范围较小;②采用热风风量控制模式,对叶丝特征尺寸(de)的下降影响程度较小,而叶丝特征尺寸(de)的稳定性较差,且叶丝特征尺寸(de)的波动范围比采用筒壁温度控制模式的波动范围略大;③两种控制模式下的叶丝感官质量差别不大,香气风格一致,在烟气风格特征上略有差别.     

Heating process of soybean using hot-air and superheated-steam fluidized-bed dryers

The present work investigated drying characteristics and inactivation of urease in soybean dried by superheated-steam and hot-air fluidized beds. The value of effective diffusion coefficient, which was determined by a method of slopes, was increased with increased drying temperature and increased moisture content. Furthermore, it depended on the type of heating medium, with higher moisture diffusion for soybean dried by hot air. Inactivation of the urease enzyme in both media showed difference in rate, in which the enzymatic inactivation was faster for soybean dried in superheated steam than in hot air. For the individual heating medium, the modified first-order reaction was adequately fitted to experimental data. The rate of inactivation was found to increase as the temperature and moisture content were increased. The urease enzyme was inactivated, along with maintaining protein solubility and lysine content being in standard range, as soybean was treated at a temperature between 135 and 150 °C for the hot air and the treatment temperature could be reduced to be lower than 135 °C by using superheated steam.     

烘丝控制模式的建立与实现

通过对烘丝过程的分析 ,针对现有烘丝控制系统的不足 ,提出了新的控制模式。正常工作时稳定进入烘丝筒内烟丝的脱水量以及烘丝筒的筒壁温度 ,从而稳定烘后烟丝的含水率。在热风管道上增加一个由电磁阀控制的低压蒸汽喷射装置 ,“模拟”正常烘丝过程中筒内的环境 ,以减少“干头”和“干尾”烟丝量。使用新的控制模式 ,提高了烘后烟丝含水率的稳定性 ,“干头”和“干尾”烟丝数量大幅减少     

热风-远红外联合干燥肉脯的工艺优化及其品质研究

为提高肉脯品质,本文研究了不同干燥技术对肉脯品质的影响,以水分含量、剪切力、色差和质构为指标,通过单因素和正交试验优化热风-远红外联合干燥肉脯的工艺条件,确定干燥模型,并对比分析微波、热风、远红外干燥技术对肉脯品质的影响。结果表明:热风-远红外联合干燥肉脯的最佳工艺为:第一段热风干燥温度Ⅰ170℃,第二段热风干燥温度Ⅱ 250℃,第三段红外烤制温度Ⅲ 260℃,干燥100 s,制得肉脯的水分含量低(13.54±0.48) g/100 g,嫩度高,易咀嚼,符合Modified Henderson and Pabis干燥模型(R2=0.9976);与微波干燥、热风干燥和远红外干燥相比,热风-远红外联合干燥的肉脯品质最佳,改善了产品的感官质量,水分含量、剪切力、硬度、咀嚼性、L*值和a*值分别是热风干燥的92%、55%、60%、46%、109%和121%,胶粘性和b*值无显著差异。该研究为肉脯的干燥加工提供了理论依据。     

Effects of microwave and infrared drying on the quality of carrot and garlic

The effects of microwave and infrared drying on the quality of carrot and garlic were studied and compared with the effects of conventional hot air (tray drier for carrot and fluid bed drier for garlic) drying. The quality of carrot and garlic were evaluated by instrumental and sensory analysis. Rehydration, moisture content, water activity, particle density, bulk density, porosity and colour values were obtained for microwave, infrared and hot-air dried vegetables. In addition, total moisture content versus time was represented by drying rate curves of carrot and garlic samples. Finally, free moisture content versus drying rate were compared for the three different drying methods.     

COMAS烘丝机工艺参数与叶丝质量的测试分析

为提高COMAS烘丝机烘后叶丝膨胀效果 ,对影响叶丝膨胀效果的有关工艺参数进行了测试分析。结果表明 :①改变切丝宽度可影响叶丝填充值。高档烟叶丝宽度为 0 .95mm时填充值最高 ;低档烟叶丝宽度为 1.2 0mm时填充值最高。②叶丝填充值随加料后叶片含水率的增大而增大 ,随烘前叶丝温度的增加而增加。③在设备能力范围内 ,叶丝填充值随物料流量的增大而间接增大。④在烘前叶丝含水率和温度一定的情况下 ,增加烘丝机筒壁温度并与适宜的热风温度及热风风速相配合 ,有利于提高烘后叶丝质量。     

热风与微波及其联合干燥对香椿芽品质的影响

以香椿芽为材料,比较研究热风干燥、微波干燥和热风-微波联合干燥3 种方式对香椿芽干燥特性和品质的影响。结果表明,60 ℃热风干燥和550 W微波干燥所得干制品的综合评价值较大,分别为0.890和0.884。热风-微波联合干燥的最佳干燥工艺条件为前期采用60 ℃热风干燥至转换点干基水分含量0.67 kg/kg,后期采用功率330 W进行微波干燥;在此条件下,联合干燥所得干制品的综合评价值为0.972。说明热风-微波联合干燥可以很好地保持香椿芽的品质。     

Effect of high-temperature fluidized-bed drying on cooking, textural and digestive properties of waxy rice

In this work, changes of the cooking and pasting properties as well as starch digestibility of waxy rice (RD6) during hot air fluidized bed drying were investigated. Re-moistened waxy rice at an initial moisture content of 28% dry basis (d.b.) was dried at 90-150 °C. Semi-dried waxy rice was tempered and dried again by ambient air until the moisture content reached 16% (d.b). It was found that the degree of gelatinization increased with an increase in the drying temperature. At 130 and 150 °C the appearance of some waxy rice kernels changed from opaque to translucent, indicating complete gelatinization. Thermal degradation of amylopectin granules during high-temperature drying caused the starch to be more rapidly digested; this led to lower peak viscosity and setback viscosity. In addition, waxy rice processed at higher drying temperatures (90-150 °C) could adsorb more water and exhibited larger loss of solids during soaking. Such effects subsequently led to samples with lower hardness and higher stickiness. Based on the sensory analysis results, however, waxy rice dried at the above temperatures, when cooked, did not significantly differ in overall acceptability from the reference waxy rice.