重质碳酸钙活化的研究

采用硬脂酸对1500目重质碳酸钙进行湿法活化,利用正交实验研究了硬脂酸加入量、反应温度和反应时间对活化效果的影响。测定了改性前后重质碳酸钙活化度,并用红外光谱进行表征。     

鸡蛋壳催化大豆油酯制备生物柴油

以废弃鸡蛋壳为原料制得固体碱催化剂,催化大豆油与甲醇的酯交换来制备生物柴油。利用热重分析仪、低温氮气吸附脱附仪等对制备的催化剂进行了表征。实验结果表明：950℃下焙烧3.0h制得的催化剂活性最佳。制备生物柴油的最佳工艺条件为：醇油物质的量比10∶1、催化剂质量分数为3.0%、反应时间3.0h。在最佳工艺条件下,生物柴油收率可达98.9%。对催化剂的稳定性做了进一步研究,实验结果表明：制备的催化剂在重复使用13次以上,仍保持了较高的催化活性,生物柴油收率可达到98%以上。     

碳酸钙沉淀势理论计算模型及其应用

水质化学稳定性评价指数较多,其中碳酸钙沉淀势(CCPP)是一个能定量分析CaCO3溶解或沉淀的精确指数.从理论上推导了CCPP计算模型,并基于Matlab计算求解.模型计算结果与已有相关软件的计算结果相比,该理论模型的计算值更接近试验结果,可以用其代替试验值进行水质化学稳定性分析.     

均匀设计在烷基水杨酸钙合成中的应用

运用均匀设计对烷基水杨酸钙碱化反应进行研究，成功解决了产品钙含量、碱值偏低的主要问题。探讨了促进剂第一次和第二次加量、溶剂量及C02流量等因素的影响，建立了钙含量和碱值的数学模型，通过参数优化，确定了优化工艺条件。实验结果表明，在保证烷基水杨酸投料一定的前提下，促进剂两次进料比约为50：(60—65)g，溶剂用量为135—150g，C02流量控制在150ml/min以下，产品钙含量可达6．85％，碱值可达187mgKOH/g，产品质量明显提高。同时说明采用均匀设计进行实验，不仅可以提高工作效率、提高试验水平、节约时间、节约经费，而且利用它所建立的数学模型及模拟的单因素变化规律符合实际反应情况，并能进行推确、有效的预报，对生产具有积极的指导作用。     

Thermodynamics of Hydrogen Production Based on Coal Gasification Integrated with a Dual Chemical Looping Process

The performance of an innovative hydrogen production technology, which is based on a coal gasification system integrated with a dual chemical looping process, namely, chemical looping air separation (CLAS) and calcium looping CO₂ absorption (CaL), is evaluated. CLAS offers an advantage over other mature technologies in that it can reduce capital costs considerably. CaL is an efficient method for hydrogen production and CO₂ capturing. The proposed technologies are studied by Aspen Plus based on the Gibbs free energy minimization principle. The key factors in terms of reduction temperature, gasification pressure, temperature of water‐gas shift reaction, and water consumption, which proved to have a significant impact on the performance of the whole hydrogen generation process, are discussed.     

Mesophilic biohydrogen production from calcium hydroxide treated wheat straw

The use of Ca(OH)₂ pre-treatment to improve fermentative biohydrogen yields, from wheat straw was investigated. Wheat straw was pre-treated with 7.4% (w/w) Ca(OH)₂ at ambient temperature (20 °C) for 2, 5, 8, and 12 days, prior to 35 °C fermentation with sewage sludge inoculum. Biohydrogen yields were evaluated during dark fermentation and simultaneous saccharification fermentation (SSF) of total pre-treated straw material and compared to those from separated solid and hydrolysate fractions. Ca(OH)₂ pre-treatment followed by SSF, exhibited a synergetic relationship. On average, 58.78 mL-H₂ g-VS⁻¹ was produced from SSF of pre-treated and filtered solids. This was accompanied by approximately a 10-fold increase in volatile fatty acid production, compared to the untreated control. By omitting pre-treatment hydrolysate liquors from SSF, H₂ production increased on average by 35.8%, per VS of harvested straw. Additional inhibition studies indicated that CaCO₃, formed as a result of pre-treatment pH control, could promote homoacetogenesis and reduce biohydrogen yields.     

电石生产用石灰质量的控制

通过麦尔兹窑生产过程阐述了石灰质量控制的要点。为保证生产出优质石灰,应对原料和燃料的杂质进行控制,同时还应选择合理的石灰石粒度、煅烧温度、压力和煅烧时间。     

Properties of gas detonation ceramic coatings and their effect on the osseointegration of titanium implants for bone defect replacement

An optimal performance of bone implants with bioceramic coatings is closely related to the surface modification technology. For the first time, we have evaluated a gas detonation deposition (GDD) approach to obtain biocompatible ceramic coatings based on bioglass (BG) and calcium phosphates on Ti-based alloys as prospective materials towards their application for the development of bone implants. For the production of the coatings, hydroxyapatite (HA), HA metal-substituted (containing Ag⁺, Cu²⁺, or Zn²⁺) and tricalcium phosphate (TCP) were synthesized and characterized. Pure powders and their combination with BG were used to obtain coatings on a Ti–6Al–4V alloy using the developed automatized GDD setup. The microstructure, phase and chemical composition of the produced coatings were studied using XRD, SEM-EDS and Raman spectroscopy. The produced coated materials were evaluated in vivo in Wistar rats to analyze a reparative osteogenesis over a period of 12 weeks. The results regarding the optimization of the GDD method indicate its high productivity, as confirmed by high deposition rates. The highest deposition rate was observed for the coatings obtained from the HA metal-substituted powders. The results revealed a partial transformation of a HA phase to an α-TCP phase during the deposition, with a prevalence of the HA-phase in the coatings. According to the histological evaluation, the reparative osteogenesis occurs through the perimeter of the titanium implants, whereas the regeneration level increases from the 4th to the 12th week. The highest osteointegration level was detected for the implants coated with a biocomposite consisting of BG, HA and TCP. The results of the current study demonstrate an effectiveness of the GDD method to produce biocompatible coatings on Ti-based alloys. This provides excellent prerequisites towards the application and standardization of the GDD technology to manufacture bone implants for bone fixation and defect replacement, as well as the development of dental implants.