Creep testing of carbon containing refractories under reducing conditions

Mechanical testing of carbon containing refractories at high temperatures requires measures to protect the sample from oxidation. Therefore, special setups for tensile and compressive creep testing were developed to prevent the oxidation of carbon in the sample. A MgO-C refractory was selected for a case study. These developments allow the quantification of the tensile and compressive creep behaviour of MgO-C refractories at temperatures up to 1500?°C. The creep parameters are determined by an inverse evaluation method for the obtained experimental data. They enable the consideration of creep in a thermomechanical finite element simulation of refractory linings in service.     

Optimum surface area distribution of quadruple-effect evaporator in sugar juice evaporation process

The evaporation process in raw sugar manufacturing consists of juice heater, multiple-effect evaporator, and crystallizer. Two performance parameters of the evaporation process are the rate of processed sugar juice and the steam economy, defined as the ratio between water content of sugar juice entering the process to the amount of steam required to run the process. If the total surface area of the multiple-effect evaporator is fixed, the performance parameters are affected by the distribution of the surface area among the effects of the evaporator. Although the optimization of evaporator surface area distribution has been investigated in previous studies, they have considered only the multiple-effect evaporator, and overlooked interactions between the three components of the evaporation process. The current investigation proposes a model of the evaporation process that takes into account interactions between the three components of the process through mass and energy balances. The model is used to find the optimum surface area distribution that maximizes the rate of sugar juice processed by the system and the optimum surface area distribution that maximizes the steam economy are different.     

糖醇的选择性衍生-毛细管电泳检测法

建立了糖醇的CE-紫外衍生法:以三氧化二铝/甲烷磺酸为催化体系,苯甲酸为衍生化试剂,选择性酯化糖醇。以新型混合取代环糊精衍生物添加剂,分离检测不同糖醇。木糖醇、甘露醇、山梨醇、阿拉伯糖醇均得到较好分离,且木糖醇、甘露醇、山梨醇这三个糖醇的检测限分别达到9.1 ng/L,6.3 ng/L,10.2 ng/L。     

大温变率流场中特种温度变送器的研制

在还原性气氛流场瞬变温度测量中,过去一般采用全铠装式或接壳式热电偶,很难实现毫秒级的时间常数,新研制的大温变率流场中特种变送器,由镍铬-镍硅的偶丝裸露式极微细热电偶,及放大电路、冷端补偿电路和超量程限幅电路等组成的仪表放大器2部分构成,首次应用在还原性气氛流场温度测量中,获得了满足试验要求的毫秒级时间常数,其中,以精密电压基准LM385为核心器件的热电偶冷端补偿电路,在0℃-40℃环境温度范围内补偿,温度附加误差为0.2%,提高了系统测量精度。     

低糖菠萝柠檬保健复合果酱的研制

以菠萝、柠檬为原料,用果糖代替部分蔗糖,使产品可溶性固形物控制在40%以下,并采用低甲氧基果胶为凝固剂,通过正交试验确定最佳低糖复合型果酱的配方,研制出香气浓郁,营养价值高的低能保健果酱.     

食品中糖类的测定方法探讨

本文从地方基层检测机构的实际情况出发,以国家推荐的直接滴定法测定还原糖为基础,分别探讨了在规定的实验条件下还原糖、蔗糖、总糖的测定,并对影响因素进行探讨,提出改正措施和注意事项,有效地降低了还原糖、蔗糖和总糖的实验不确定度.     

论糖蜜稀释对煮糖的影响

糖蜜稀释在制糖企业生产当中起着举足轻重的作用,稀释的好坏程度关系到糖膏煮制的结晶率和结晶速度的提升,是制糖企业提升综合实力的重要因素.本文通过强化糖蜜稀释工作,进行不同的实验对比分析糖蜜稀释对乙、丙糖膏结晶率、煮炼时间等因素的影响,论述重视糖蜜稀释工作的重要性.     

赤砂糖中二氧化硫含量测定的不确定度分析

采用GB 5009.34-2016《食品安全国家标准食品中二氧化硫的测定》中蒸馏法对赤砂糖中二氧化硫进行测定,分析该方法不确定度来源,对不确定度各个分量进行评估.结果表明,测定赤砂糖中二氧化硫含量不确定度的主要来源为标准滴定溶液消耗的体积和重复性测量,当二氧化硫含量为0.053 g/kg时,扩展不确定度为0.0034 ...     

Transient shrinkage behavior of wustite-centered binary/ternary/quaternary/quinary-component oxide packed beds in a reducing atmosphere up to 1773 K

Wustite (FeO)-centered multicomponent oxides play an important role in the ironmaking process, and a complete understanding of their high temperature behaviors is of great importance for process optimization to achieve high efficiency and low emissions during industrial production. In this work, the transient shrinkages of FeO-centered multicomponent oxide packed beds are quantitatively determined in a reducing atmosphere up to 1773 K, and the effects of the interactions between the oxides on the shrinkage rate (SR) are qualitatively evaluated. The results show that although mixing CaO with FeO increases the SR to 0.42%/K below 1173 K, further mixing with SiO₂ or Al₂O₃ significantly limits this enhancement effect due to the formation of an olivine or spinel phase. However, in the subsequent stage, the SR increases to as high as 0.44%/K after CO is injected. The interaction between FeO and MgO leads to an SR of greater than 0.20%/K at lower temperatures, but it causes a decrease in the SR from 0.33%/K to 0.16%/K between 1173 K and 1273 K. Meanwhile, adding SiO₂ slows the reduction reaction, and the SR correspondingly decreases further to 0.04%/K. On the other hand, the interaction between CaO and Al₂O₃ takes precedence over the interaction between SiO₂ and MgO and dominates the shrinkage process in the quinary-component case, and the preferentially formed CaAl₂O₄ spinel phase hinders the formation of the Mg₂SiO₄ olivine phase.     

Optimization of Enzymatic Process Condition for Protein Enrichment,Sugar Recovery and Digestibility Improvement of Soy Flour

Soy protein is a valuable nutritional supplement for food and animal feed. While protein constitutes ~50 % of defatted soy flour (SF), it coexists with complex carbohydrates (30–35 %) which may have anti‐nutritional effects. An enzymatic process can remove the carbohydrate and produce protein‐enriched soy products. The hydrolysate with monomerized carbohydrates is valuable fermentation feedstock. In this study, Aspergillus niger and Trichoderma reesei enzymes were compared for use in the process. Effects of pH (3.2–6.4), temperature (40–60 °C), enzyme‐to‐SF ratio (0–2 ml/g) and SF loading (150–350 g/l) were evaluated for the enzymatic conversion of SF carbohydrate to reducing sugar (Y_RS) and total soluble carbohydrate (Y_TC) in the hydrolysate. Effects of these single factors and interactions between factors were investigated. Optimal pH and temperature were similar for both enzymes: pH 4.8 and 50–51 °C for Y_TC, and pH 5.1–5.2 and 48–51 °C for Y_RS. The two enzymes also gave similar protein contents in resultant soy protein concentrates, i.e., 74–75 % with 2 ml/g enzyme broth and 150 g/l SF, which were higher than the 64–68 % protein in commercial concentrates. A. niger enzyme was significantly more effective in carbohydrate conversion, achieving Y_RS = 75 % and Y_TC = 78 % with 2 ml/g enzyme and 150 g/l SF, higher than the Y_RS (30 %) and Y_TC (64 %) obtained with T. reesei enzyme. Monomerization was essentially complete in hydrolysate produced with A. niger enzyme.