响应曲面法优化提取柴胡总皂苷的工艺

采用乙醇加热回流提取柴胡皂苷,研究乙醇浓度、料液比、提取时间、提取温度对柴胡总皂苷得率的影响。结果表明,柴胡总皂苷的提取工艺条件是:乙醇提取浓度69%,温度61℃,时间150 min,料液比1∶20g/mL,在此工艺参数下,柴胡皂苷的得率为3.12%。     

内蒙古某褐煤干燥特性的实验研究

利用热风干燥实验装置对内蒙古某褐煤进行不同温度、不同风速、不同粒度的干燥特性研究。结果表明：降低褐煤的粒度可有效缩短干燥时间;热风风速对褐煤的干燥速率影响很小,干燥适宜温度为150~165℃,在此温度区间内干燥时间较理想,进一步提高风温虽然有助于提高干燥效率,但有发生自燃的危险。     

流化床热风干燥胡萝卜片及护色工艺研究

对胡萝卜片进行了热风干燥及护色实验,并用多因素正交实验方法,分析了各种因素对实验指标的影响。结果表明,胡萝卜片干燥的最佳工艺参数为:风速为1.42 m/s,风温为50℃,漂烫水温为95℃,漂烫时间为3 min,含水率可达到6%。     

杉木木束热风循环干燥参数对干燥效率与能耗的影响

利用热风循环干燥的方法，对铺装方式、转筒速度、装载量、初含水率、气流温度、气流速度等影响木束干燥效率和能耗的因素进行实验研究，探讨木束热风循环干燥参数对干燥时间和能量消耗的影响。实验结果表明，各参数对干燥结果的影响程度不一，按显著程度排序为：气流速度、初含水率、气流温度、装载量、铺装方式、转筒转速。     

番木瓜的自身特性及干燥温度对干燥特性的影响研究

对番木瓜片进行了热风薄层干燥实验,主要考察了番木瓜自身的不同条件(包括成熟度、厚度、形状)与干燥温度对干燥速率的影响,通过实验数据建立了番木瓜片的热风干燥的水分比与干燥时间关系的联系,根据Page模型进行了拟合检验,结果显示模型的预测值与实测值拟合良好。     

天然胶乳厚胶膜热风干燥与红外干燥对比研究

采用失重法研究了天然胶乳厚胶膜在热风与红外线两种干燥方式下的干燥过程。研究结果表明,在相同条件下,红外干燥的干燥速率常数远大于热风干燥,采用红外干燥可大大缩短干燥时间,干燥温度和厚度均显著影响干燥过程,红外干燥对温度更敏感。通过动力学拟合结果,得到了干燥动力学方程,可以预测干燥时间。     

耐火浇注料对流与微波干燥的实验研究

进行了耐火浇注料热重分析,热风和微波干燥实验研究,得到了浇注料热风和微波干燥特性曲线。实验结果表明,与热风干燥比较,微波加热极大地降低了耐火浇注料干燥时间、提高了干燥效率和能源效率高,在耐火浇注料干燥过程中有着广阔的应用前景。     

热风干燥条件对干燥特性影响及数学模型研究

为了有效提高恒速干燥阶段的干燥速率,对干燥过程的温度、风压等干燥变量进行了研究与分析,通过实验研究干燥变量对干燥过程中干燥物料的影响,选取8种干燥数学模型进行拟合分析,并建立验证最优干燥过程数学模型。结果表明:干燥速率随温度升高而增大,干燥时间随温度升高而减小。有效水分扩散系数3.5498×10^-10m²/s-6.8461×10^-10m²/s,平均活化能21.67k J/mol。Wang函数模型能较好的描述工业呢(帆布)热风干燥过程(R²:0.9983～0.9998,RMSE:0.0008～0.0064,χ²:0.0001～0.0004),对实验过程的拟合度较优。     

氯气干燥工艺优化

通过优化氯气干燥工艺,将1个泡沫筛板塔逐步改成氯气洗涤塔、两级钛冷器、两级填料干燥塔、一级泡罩填料复合塔,使氯气含水由0.05%~0.10%降低到0.005%以下,从而满足氯气用大型氯压机输送的要求,减轻对设备、管道的腐蚀。     

太阳能-除湿-常规分段组合木材干燥工艺优化

为降低木材干燥能耗,通过对杨木进行太阳能-除湿-常规分段组合干燥,即含水率40%以上采用太阳能进行预干,25%—40%采用除湿干燥,25%以下采用常规干燥,并与常规干燥进行干燥能耗和木材质量的对比。结果表明,分段组合干燥比常规干燥节能19%左右,而且干燥质量和常规干燥基本一致。分段组合干燥充分利用了三者各自的优势,从而达到节能的目的。     

Infrared Drying: From Process Modeling to Advanced Process Control

The article surveys the drying of solids materials and polymer solutions when infrared radiation (IR) is employed as the main heating source. The study reviews the current research trends of IR drying of specific applications. A case study similar to an industrial setting is presented to illustrate a model development and control scheme of an IR drying unit. The design and online implementation of an internal model controller (IMC) is discussed. The study demonstrates the controller capabilities to suppress random variations of the moisture content in the material entering the dryer. Simulation results also showed the success of model predictive control (MPC) multivariable controller ability, while handling process interactions and process constraints, to track setpoint changes in the humidity and temperature of the material exiting the dryer and to reject unmeasured stochastic disturbances in the inlet humidity stream.     

Infrared Drying: From Process Modeling to Advanced Process Control

The article surveys the drying of solids materials and polymer solutions when infrared radiation (IR) is employed as the main heating source. The study reviews the current research trends of IR drying of specific applications. A case study similar to an industrial setting is presented to illustrate a model development and control scheme of an IR drying unit. The design and online implementation of an internal model controller (IMC) is discussed. The study demonstrates the controller capabilities to suppress random variations of the moisture content in the material entering the dryer. Simulation results also showed the success of model predictive control (MPC) multivariable controller ability, while handling process interactions and process constraints, to track setpoint changes in the humidity and temperature of the material exiting the dryer and to reject unmeasured stochastic disturbances in the inlet humidity stream.     

Optimization of the Drying Process: An Application to the Drying of Garlic

The response surface methodology (RSM) was used to derive an optimum drying condition for garlic drying. The responses analyzed were L* value and Optical Index (OI) as a measure of color and rehydration ratio (RR) as well as final moisture content (Mf) which are important quality attributes of dehydrated products. L*, OI, RR and Mf varied from 70.6 to 85.0, 72.0 to 191.1, 2.2 to 3.2 and 5.4 to 10.2 % MC, respectively. An analysis of variance (ANOVA) revealed that drying temperature and slice thickness significantly (90% confidence level) affected L*, OI and RR while no effect was observed for airflow rate and relative humidity (RH). An optimum drying temperature of 70°C for drying 2 mm garlic slices is recommended.     

谷物干燥企业工艺优选模糊综合评价

我国现有谷物干燥工艺种类多，工艺性、经济性等指标繁杂，企业不容易选择。针对这一问题，运用多级模糊综合评价方法，对实际生产中有代表性的谷物干燥工艺进行综合评价，使得对工艺方案的评价具有准确性和客观性。通过建立数学模型，经过分析计算，结论基本合理，且本方法简单实用，为企业选择优良的生产工艺提供了理论依据。     

火焰原子吸收法测定柴胡药材中的五种微量元素

通过对川产柴胡药材中5种微量元素的定量分析,评价微量元素与柴胡药材功效之间的关系。采用微波消解法消解柴胡样品,用原子吸收光谱法测定钙、铁、铜、锌、镁的含量。该方法的加标回收率为97.46%～102.32%,RSD〈1.10%,具有良好的准确度和精密度。结果表明：柴胡药材中钙、铁、镁含量较高,铜、锌含量较少。     

Characterization and Process Optimization of Microwave Drying of Plaster of Paris

The changes in the characteristics of plaster of Paris (pop) during drying operation under microwave irradiation conditions, namely surface morphology, effective moisture diffusivity, and absorption of microwave, were studied. The drying characteristics and kinetics of the process during microwave drying of plaster were studied for rectangular-faced cuboids (80 × 70 × 15, L × B × H in mm) through various drying parameters like microwave power input, initial moisture content, and drying time. Further, the experimental data on moisture ratio of plaster for different operating conditions were obtained and the optimization of the microwave drying process parameters was performed with response surface methodology (RSM) by considering all the above-said independent variables. Based on the RSM analysis, the optimum values of the process variables were obtained as: initial moisture content (A) 60%; microwave power input (B) 180 W; and drying time (C) 480 S.     

Optimization of Process Parameters for Spray Drying of Fermented Soy Milk

Generally used as an inexpensive source of high-quality protein with many other health-promoting properties, soy milk offers an interesting alternative when fermented. Fermentation with lactic acid bacteria brings about the value addition to soy milk, making a nutritious probiotic food product. Dehydration helps to achieve longer shelf life and easier transportation and storage, enabling wider distribution of the product. The present work pertains to optimization of process parameters for spray drying of fermented soy milk using response surface methodology (RSM). The process parameters studied include inlet air temperature, aspirator speed (air flow rate), feed flow rate, and atomization pressure. The experiments were designed using the central composite design tool. Residual moisture content was found to be low at higher inlet air temperature, lower feed flow rate, higher atomization pressure, and higher air flow rate. Porosity reduced with increased atomization pressure. Higher product yield was obtained at high air flow rate and low feed flow rate. The increase in the atomization pressure increases the cohesiveness between particles, resulting in reduced flowability. An increase in the inlet air temperature greatly reduces the viability and the isoflavone aglycone content in the product. Protein denaturation during the process was found to reduce the product solubility.     

Enhancing the Energy Efficiency of Domestic Dryer by Drying Process Optimization

The domestic tumble dryers are becoming indispensable household appliances and responsible for up to 10% of the total residential energy use in developed countries. However, their energy efficiency is low. In this paper, the development of a multi-sensor computer-controlled prototype platform for fabric drying is described for improving the efficiency of dryers. The prototype platform enables the real-time control and recording of key drying parameters including heater power, air flow velocity, rotating speed of drying drum, and drying cycle time. These parameters are automatically adjusted according to the exhaust air humidity instead of the temperature which is used traditionally. Additionally, a new drying model of dividing the drying process into four stages based on the humidity of the exhaust air has been investigated to further increase the energy saving. The performance of this staged drying model is experimentally evaluated in respect to energy consumption, drying time, and the smoothness of fabric after drying. The results clearly indicate that the staged controlling of heating power input not only decreases energy consumption by 21.5%, but also improves the fabric smoothness by 0.9 grade compared to using a single heating power input for the whole drying process. The research outcome can enable the design and production of new dryers that are more energy efficient and lead to dried clothes that require less ironing, which in turn further reduces energy consumption.     

优化硝酸工艺 提高氨氧化率

硝酸生产过程中,氨氧化率会对硝酸产量产生直接影响,首先对硝酸生产原理进行概述,明确影响氨氧化率的主要因素,针对这些因素提出了相应的优化措施,旨在进一步提高硝酸生产过程中的氨氧化率。