Non-conventional high-pressure extraction process: A comparative study for astaxanthin recovery from Xanthophyllomyces dendrorhous

Xanthophyllomyces dendrorhous is one of the most attractive natural sources of astaxanthin. The yeast produces the compound intracellularly, therefore, it is necessary to evaluate cell rupture methods using clean and efficient technologies for its extraction and it subsequent use in industries. At present work, two non-conventional high-pressure extraction methods were evaluated for astaxanthin recovery: Supercritical fluid extraction and microfluidisation. Results: Effect of pressure (15, 30, and 45 Megapascals; MPa), Temperature (313 and 343 °K) and usage of co-solvent were studied in supercritical extraction process, meanwhile the effect of microfluidisation process (five stages and 160 MPa) for cell rupture and its combination with conventional technics (lithic enzymes, glass beads and ultrasonication) for the recovery of astaxanthin were evaluated. Supercritical fluid extraction presented a higher astaxanthin recovery, 54% yield extraction, at 32.5 MPa and 313 °K, and using ethanol as co-solvent, compared to a 31% yield extraction by mean microfluidisation process at 160 MPa combined with 15 min of sonication (amplitude of 80%).     

石油化工装置安全设计讨论——Ⅱ.设备安全设计

设备设计是设备本体安全的保障,要保证过程设备受压元件有足够的强度、刚度、稳定性、耐蚀性。设备工艺负荷不仅决定于工艺参数的确定,而且涉及设备所具有的外形尺寸和结构形式。设备结构材料的选择,除遵循规范强制性要求和特殊禁用规定外,还应考虑材料与过程介质的相容性、与过程条件的适用性以及材料的可加工性;泵和压缩机滑动和转动部件的磨擦是降低使用寿命和发生故障的主要原因,机泵不平衡力和周期性性能变化则是机泵产生振动或脉动导致机器设备和管道疲劳失效的主要原因;加热炉辐射段和对流段炉管的最高内膜温度不应超过允许值,当超过允许值时会导致介质裂解并在管内壁结焦导致传热不良,出现局部过热到过烧乃至炉管破裂,还应根据操作条件来考虑热膨胀问题,否则未预计的热膨胀增量会导致加热炉结构的破坏。     

适用于小型热气机性能试验的电加热器的研制

介绍了一种针对小型家用热气机性能试验开发的电加热器系统.该电加热器可以模拟性能试验时外燃系统对热头的加热情况,精确控制输入的热量.针对不同材料不同形式的加热器进行理论试验研究,确定并制造了应用于试验的电加热器系统.试验验证了其可行性,可满足家用小型热气机性能试验的要求.     

室内外消防合用稳高压系统在实际项目中应用

根据GB 50016-2006建筑设计防火规范,结合某山地建筑的具体特点,分析采用室内外消防合并的稳高压消防给水系统的优点、系统设计要点以及需采取的技术措施,对今后同类项目具有一定指导意义。     

直拉单晶炉减薄型加热器的数值模拟与实验分析

在直拉单晶炉中使用一种减薄型加热器替代原加热器,改变了单晶炉的热场温度分布。通过有限元模拟分析软件对减薄型加热器进行模拟分析,模拟结果指出减薄型加热器对提升单晶拉速、降低单晶炉功耗具有促进作用。通过对比两种加热器装料量,并进行单晶生长对比实验,实验指出,减薄型加热器在引晶、等径、收尾阶段均降低了功耗,提升了拉速。最后,数据分析指出减薄型加热器的经济性比原加热器有一定提升。     

凝汽器和给水加热器用不锈钢焊管制造质量控制细探(上)——兼评“某国产凝汽器不锈钢焊管耐点蚀性的研究”一文之不足及补正

凝汽器和给水加热器是超超临界电站设备中可采用不锈钢焊管制造的部件。国内虽早已具备此类高档次不锈钢焊管的生产条件,却至今仍难以达到高标准要求而进入国际市场竞争。结合小直径连续不锈钢焊管生产现状探讨了此类焊管制造质量控制要素。介绍了两个冷凝器失效案例,借以指明此类换热器失效泄漏的原因,指出304钢管并非此类应用的理想选择,并讨论了不锈钢焊管制造标准等细节。     

直热式空气源CO2热泵热水器系统运行特性试验研究

设计了一种直热式空气源CO₂热泵热水器系统,利用试验研究的方法研究了环境温度、气冷器冷却水入水温度及流量对系统性能的影响。试验结果表明:设计的空气源CO₂热泵热水器系统,其系统能效系数(COP_h)基本达到了国家标准;环境温度、气冷器冷却水入水温度以及流量对系统COP_h、系统制热量以及气冷器出水温度的影响显著。通过调节热泵热水器系统低温热源温度、气冷器冷却水入水温度及流量,可改善系统COP_h,提高系统制热量以及气冷器出水温度。     

Effect of roughness height ratio in V down perforated baffle roughness on thermohydraulic performance of solar air heater: an experimental study

A substantial improvement in the thermal performance of solar air heater is found by using roughness on the underside of the absorber plate. In the present investigation, the effect of relative roughness height of roughness element on the thermohydraulic performance of solar air heaters is carried out. The range of roughness and flow parameters for the investigation are relative roughness height (e/H): 0.285–0.6, relative roughness pitch (P/e): 2, angle of attack (α): 60°, open area ratio (β): 12% and Reynolds number (Re): 3800–19,000. The relative roughness height of 0.285 is thermohydraulically better in comparison to other relative roughness heights. The results show that the V down perforated baffles is thermohydraulically better than the solid baffles.     

Effect of High Pressure Pretreatments on Structural and Dehydration Characteristics of Aloe Vera (Aloe barbadensis Miller) Cubes

The effect of high-pressure (HP) pretreatments (300–500 MPa for 5–15 min) on dehydration characteristics of aloe vera cubes (AVC), dried at 50–70°C and air velocity of 1–2 m/s, was studied. Pretreatments resulted in higher drying rates, leading to a reduction in drying time compared to untreated ones. The drying rate and drying time were most significantly affected (p < 0.05) by the drying temperature, followed by air velocity, pressure level, and dwell time. HPP enhanced the firmness of AVC with a maximum of up to 21% for the sample treated at 500 MPa for 15 min. Microstructural analysis using scanning electron microscopy (SEM) indicated non-uniform structures in the pretreated and dried AVC samples. Semi-quantitative elemental detection (EDS) confirmed the presence of a considerable amount (14%) of calcium in aloe vera.     

R417A喷气增焓热泵热水器低温环境下的变流量特性分析

主要研究了R417A在喷气增焓空气源热泵系统中的替代应用,重点分析了低温环境下R417A替代R22的可行性。在对带闪蒸器的涡旋式压缩机喷气增焓热泵系统的热力学分析基础上,通过试验测试确定了R22和R417A 2种制冷剂在系统中的最佳充注量,随后在热水器一次加热循环条件下改变电子膨胀阀的开度以实现对循环补气量和系统流量的调节,分析了R22和R417A 2种系统在标准工况(20、15℃)、冬季工况(7℃、6℃)及低温工况(-7℃、-8℃)下的制热量、COP、吸排气压力及补气压力等试验数据,得出结论:喷气增焓空气源热泵系统处于最佳状态时,Pm≈(PePc)1/2;环境温度越低,R417A替代R22的优势越明显,即R417A更适合在低温环境下替代R22。