气体热载体干馏炉内压力降的研究

油页岩在气体热载体干馏炉内干馏过程中,由于块状堆料之间存在不同的空隙,导致气体在空隙中通过,由于阻力的作用,压力会产生损失,行成一定的压降。本研究采用散料层阻力损失计算公式和Ergun方程两种方法对干馏炉的压力降进行计算,并与实际压降进行比较,结果发现这两种方法所得理论值与实际值比较接近,而且变化趋势与实际值基本一致,利用Ergun方程更适用于工程运行。     

Antioxidant activity and quality of asparagus affected by microwave-circulated water combination and conventional sterilization

Green asparagus (Asparagus officinalis L.), as a healthy and perishable vegetable, is processed after harvest to minimize the deterioration of its physical and chemical quality. In our research, fresh asparagus was sterilized using several methods, including a pilot-scale 915 MHz microwave-circulated water combination (MCWC) heating system, pressured hot-water heating and steam-heating in a retort. Rutin content of asparagus processed by these methods did not show significant difference. But antioxidant activity of asparagus after MCWC treatment was significantly greater than that processed by other methods. Although the shear stress of asparagus spears was significantly decreased by eight times after sterilization, no significant difference existed among the textures of asparagus processed by these methods. Asparagus processed by MCWC showed greener colour with negative a* value and greater hue value (H⁰) than did hot water- and retort-treated asparagus. Therefore, asparagus sterilized by MCWC showed greater antioxidant activity and greener colour than did asparagus processed by the conventional methods.     

Endospores of Thermophilic Bacteria in Ingredient Milk Powders and Their Significance to the Manufacture of Sterilized Milk Products: An Industrial Perspective

Milk powder is one of the most widely traded dairy products globally—with a large amount being used to manufacture commercially sterilized products. Milk powder invariably contains endospores of thermophilic bacteria—the dominant strains grow and produce spores in manufacturing steps operating in their temperature growth range. Although they produce proteolytic and lipolytic enzymes in vitro, and the spores have the potential to survive sterilizations, their presence in ingredient powders does not mean that spoilage of sterilized products is inevitable—treatment severity, low spore numbers in ingredient powders, variability in spore resistance, and in-market temperatures usually ensure commercial sterility.     

System variables affecting heat transfer in a canned particle in Newtonian fluid system during end-over-end rotation

Heat transfer in a canned particle/Newtonian liquid system was evaluated in a pilot-scale, full water-immersion single-cage rotary retort. High-viscosity aqueous glycerin solutions (from 75% to 100%, V/V) were used as Newtonian liquids and the effects of rotation speed, glycerin concentration, retort temperature, can size and particle material on heat-transfer rates to products were investigated. A full factorial experiment design and a CCRD experiment design were used. Flexible thin wire thermocouples and rigid thermocouples were used to measure particle temperatures and liquid temperatures, respectively. Apparent heat-transfer coefficients h_ap and apparent overall heat-transfer coefficients U_a were evaluated during end-over-end rotation. The h_ap values increased with increase in rotation speed, retort temperature and particle density, and a decrease in liquid viscosity and can size. U_a values increased with an increase in rotation speed and a decrease in liquid viscosity.     

Effects of retort conditions on ATP-related compounds in pouched fish muscle

To examine the usefulness of high-temperature short time (HTST) process on quality of retorted fish products, adenosine triphosphate (ATP)-related compounds in raw fishes and retorted fish models (10 g/pouch) heated at 115 °C for 90 min (common retort (CR) process) or 125 °C for 9 min (HTST process) were analyzed by HPLC method. The raw materials used in this study were fresh chub mackerel Scomber japonicus for sashimi (raw eating), frozen-thawed yellowfin tuna Thunnus albacares for sashimi, frozen-thawed pink salmon Oncorhynchus gorbuscha for cooking and frozen-thawed pink shrimp Pandalus borealis for sashimi. In all the fish samples, the level of inosine monophosphate (IMP), an umami-taste compound, was higher in HTST fishes than in CR fishes. On the other hand, inosine (HxR) and hypoxanthine (Hx), no-taste and bitter taste compounds, was high in CR fishes. K-value, an index of fish freshness defined as the ratio of the sum of HxR and Hx to the sum of ATP-related compounds, was high in CR fishes. In sensory test of pink salmon by the paired difference test, umami and sweetness in the HTST fish were stronger than the ones of the CR fish. The bitterness was stronger in the CR fish rather than in the HTST fish. These results indicated that HTST is a favorable process for retorted fish product and measurement of ATP-related compounds is useful for the quality check of retorted fishes.     

一台卧式杀菌锅爆炸事故的分析

分析了一起快开门卧式杀菌锅爆炸事故产生的原因,并提出了防止快开门压力容器发生类似事故的建议。     

聚乙烯蜡的研究进展与工业生产方法探讨

在处理废旧塑料时可以利用热裂解或者催化裂解获得聚乙烯蜡.聚乙烯蜡作为具有广泛应用前景的有机中间体,可以应用于各种领域.综合概括了聚乙烯蜡的研究进展,并介绍了自主设计的一套得到分子量为1200～1500的聚乙烯蜡产品生产装置.     

Artificial neural network model for prediction of cold spot temperature in retort sterilization of starch-based foods

An artificial neural network (ANN) model was developed for prediction of the cold spot temperature profile during retort processing using starch dispersion (STD) as a model food. STDs of different concentrations were prepared by mixing corn starch powder with distilled water at 90 °C for 30 min. Each of the partially gelatinized STDs thus prepared was filled in retort pouches and processed in a retort under various combinations of holding temperature, holding time, and rotational speed. Thermocouples were inserted into selected pouches one by one to monitor the cold spot temperature at regular intervals. The profiles of cold spot temperature together with retort temperature thus obtained were served to ANN modeling as training or validation data. Back-propagation network was chosen as the network model. Input variables for the model were current and past temperatures of the cold spot (T_n, T_n−1, and T_n−2) and current retort temperature θ_n and current time t_n. Output was the temperature of the cold spot at the next time step T_n+1. A model with 2 hidden layers, which contained 11 and 15 nodes, respectively, was the best among the models tested. Using the model developed, prediction of a whole profile of the cold spot temperature was tested, starting from temperature data of the first three time steps with a whole profile of retort temperature monitored. The results showed very good performance of the model, relative errors for F₀ value prediction being less than 2%.     

煤干馏生产半焦、煤焦油及干馏炉煤气的发展前景

介绍了国内半焦的发展现状、市场需求及综合效益。通过对半焦各项技术指标与铁合金专用焦的对比及半焦生产与煤制甲醇、煤制油、煤制化肥及煤电一体化等煤化工项目投资、消耗、定员等的对比分析，认为半焦产业发展前景广阔，并对半焦产业的发展提出了建议。     

泥炭热解研究

分析了吉林泥炭的基本特性,进行了外热式泥炭热解试验,分析了泥炭热解煤气的组成、性质及变化规律。结果表明,在适宜温度条件下,干馏热解制得的煤气成分与热值接近城市煤气。