SFP-750000/50型变压器冷却器控制方案优化改造

针对变压器冷却器能耗高的问题,分析冷却器的运行状况,提出通过优化变压器冷却设备投运方式,改造控制系统来降低冷却器能耗的措施,并通过数据计算说明节能效果.     

Emissions of ammonia,nitrous oxide,methane, and carbon dioxide during storage of dairy cow manure as affected by dietary forage-to-concentrate ratio and crust formation

Sixteen 200-L barrels were used to determine the effects of dietary forage-to-concentrate (F:C) ratio on the rate of NH₃-N, N₂O, CH₄, and CO₂ emissions from dairy manure during a 77-d storage period. Manure was obtained from a companion study where cows were assigned to total mixed rations that included the following F:C ratio: 47:53, 54:46, 61:39, and 68:32 (diet dry matter basis) and housed in air-flow-controlled chambers constructed in a modified tiestall barn. On d 0 of this study, deposited manure and bedding from each emission chamber was thoroughly mixed, diluted with water (1.9 to 1 manure-to-water ratio) and loaded in barrels. In addition, on d 0, 7, 14, 28, 35, 49, 56, 63, 70, and 77 of storage, the rate of NH₃-N, N₂O, CH₄, and CO₂ emissions from each barrel were measured with a dynamic chamber and gas concentration measured with a photo-acoustic multi-gas monitor. Data were analyzed as a randomized complete block with 4 replications. Dietary F:C ratio had no effect on manure dry matter, total N and total ammoniacal-N (NH₃-N + NH₄⁺-N), or pH at the time of storage (mean ± SD: 10.6 ± 0.6%, 3.0 ± 0.2%, 93.1 ± 18.1 mg/dL, and 7.8 ± 0.5, respectively). No treatment differences were observed in the overall rate of manure NH₃-N, N₂O, CH₄, and CO₂ emissions (mean ± SD over the 77-d storage period; 117 ± 25, 30 ± 7, 299 ± 62, and 15,396 ± 753 mg/hr per m², respectively). The presence of straw bedding in manure promoted the formation of a surface crust that became air dried after about 1 mo of storage, and was associated with an altered pattern in NH₃-N and N₂O emissions in particular. Whereas NH₃-N emission rate was highest on d 0 and gradually decreased until reaching negligible levels on d 35, N₂O emission rate was almost zero the first 2 wk of storage, increased sharply to peak on d 35, and decreased subsequently. The emission rate of CH₄ and CO₂ peaked simultaneously on d 7, but decreased subsequently until the end of the storage period. In this study, C:N ratio of gaseous losses was 32:1, reflecting higher volatile C loss than volatile N loss during storage. On a CO₂-equivalent basis, the most important source of non-CO₂ greenhouse gas emitted was CH₄ until formation of an air-dried crust, but N₂O thereafter. Taken together, these results suggested that the formation of an air-dried crust resulting from the straw bedding present in the manure reduced drastically NH₃-N, and CH₄ emissions, but was conducive of N₂O production and emission.     

Modeling and performance analysis of an absorption chiller with a microchannel membrane‐based absorber using LiBr‐H2O,LiCl‐H2O,and LiNO3‐NH3

In order to develop compact absorption refrigeration cycles driven by low heat sources, the simulated performance of a microchannel absorber of 5‐cm length and 9.5 cm³ in volume provided with a porous membrane is presented for 3 different solution‐refrigerant pairs: LiBr‐H₂O, LiCl‐H₂O, and LiNO₃‐NH₃. The high absorption rates calculated for the 3 solutions lead to large cooling effect to absorber volume ratios: 625 kW/m³ for the LiNO₃‐NH₃, 552 kW/m³ for the LiBr‐H₂O, and 318 kW/m³ for the LiCl‐H₂O solutions given the studied geometry. The performance of a complete absorption system is also analyzed varying the solution concentration, condensation temperature, and desorption temperature. The LiNO₃‐NH₃ and the LiBr‐H₂O solutions provide the largest cooling effects. The LiNO₃‐NH₃ can work at a lower temperature of the heating source, in comparison with the one needed in a LiBr‐H₂O system. The lowest cooling effect and coefficient of performance are found for the LiCl‐H₂O solution, but this mixture allows the use of lower temperature heating sources (below 70°C). These results can be used for the selection of the most suitable solution for a given cooling duty, depending on the available heat source and condensation temperature.     

Green hydrogen-based pathways and alternatives: Towards the renewable energy transition in South America's regions–Part B

Hydropower compounds most of the energy matrix of the countries of the Latin America and Caribbean region (LAC). Considering the concern in reducing Green House Gases emissions (GHG) from hydropower plants and hydrogen production from fossil sources, green hydrogen (H₂) appears as an energy vector able to mitigate this impact. Improving the efficiency of the plant and producing renewable energy the element is an interesting alternative from the ecological and economic point of view. This study aims to estimate the potential of H₂ production from wasted energy, through the electrolysis of water in hydroelectric plants in Colombia and Venezuela. The construction of two scenarios allowed obtaining a difference, considering a spilled flow of 2/3 in the first scenario and 1/3 in the second. In Colombia, hydrogen production reached 3.39 E+08 Nm³ at a cost of 2.05 E+05 USD/kWh in scenario1, and 1.70 E+08 Nm³ costing 4.10 E+05 USD/kWh in scenario 2. Regarding the Venezuelan context, the country obtained lower production values of H₂, ranging between 7.76 E+07 Nm³.d^?1 and 4.31 E+07 Nm³.d^?1, and production cost between 9.45 E+09 USD/kWh and 1.89 E+10 USD/kWh. Thus, the final cost for the production and storage of H₂ was estimated at 0.2239 USD.kg^?1. Ultimately, Colombia and Venezuela have a large potential to supply the demand for nitrogen fertilizers with green ammonia production, apply green hydrogen in manufacturing and use the surplus for energy substitution of Liquefied Petroleum Gas - LPG. In Colombia, the chemical energy offered is equivalent to 6.681 E+11 MJ/year^?1 and in Venezuela, the result is equal to 1.697 E+11 MJ/year^?1 in the conservative scenario. Finally, the countries have great potential for the diversification of the energy matrix and the insertion of renewables in the system.     

第二代高温辊式破碎机用辊轴的研究

根据傅里叶定律、牛顿冷却定律以及辊式破碎机辊轴的有关参数建立了辊轴的热传导模型,模拟计算了不同工况下的辊轴使用情况。在600℃工况温度时,辊轴采用风冷、使用40Cr材料可以安全使用;但在850℃工况温度时,辊轴材料需更换为0Cr18Ni9,或辊轴材料不变,冷却方式改用水冷,方可满足使用安全。     

Biodegradation of Ammonia Nitrogen Using a Novel Candida sp. Strain N6 Immobilization

固定化假丝酵母菌株N6降解氨氮的研究

王 凯^1,2，孙亚文¹，李斯琪¹，张瑛洁¹，程喜全¹，马 军²

（1. 哈尔滨工业大学(威海)， 海洋科学与技术学院，山东 威海 264209；

2. 哈尔滨工业大学 市政与环境工程学院，哈尔滨 150090）

创新点说明：

发现一株假丝酵母菌株，具有较高的氨氮降解能力，采用固定化技术，将其固定化后用于模拟生活污水的处理效果仍然显著，表明将该菌固定化后具有较高的应用价值。

研究目的：

将高氨氮处理效率的菌株N6固定化，以期通过固定化的形式将其应用于废水处理中。

研究方法：

从山东威海金海湾排污口分离出一株假丝酵母菌，该菌株具有较高的氨氮处理效率。采用包埋固定化技术将N6固定，考察了固定化N6的氨氮降解能力以及稳定性，通过单因素以及正交试验确定了固定化材料以及最佳固定化条件。利用SBR反应器探究固定化N6的应用情况。

研究结果：

1）当固定化材料PVA, SA, CaCl2的浓度分别为9%, 1.5%, 2%时最适合N6固定化，在此条件下，固定化N6的氨氮去除率达到了97.97%。

2）稳定性测试表明固定化N6具有很强的稳定性，固定化小球在测试条件下未出现破碎现象。

3）固定化N6的最佳固定化条件为：固定化24h，N6接种量3%，pH 8。

4） 固定化N6在SBR反应器中表现出非常好的氨氮降解能力，去除率稳定在95%-99%。

5）在固定化N6的应用过程中，最适添加量为15%。

结论：

固定化高效菌株用于废水处理具有广阔的前景。高氨氮处理效率的假丝酵母N6固定化后氨氮降解能力仍然较强。固定化N6具有潜在的应用价值，将固定化N6应用到SBR中，具有较高且稳定的氨氮去除率。

关键词：氨氮废水；固定化；假丝酵母菌属；脱氮效率

     

高密度聚乙烯装置循环气冷却器腐蚀原因分析及防护

针对高密度聚乙烯装置循环气冷却器在使用中存在的腐蚀问题进行分析。通过采用相应的防护办法,取得良好的效果。     

提高磷酸二铵产品中氮含量方法的探讨

介绍了采用添加硫酸、氯化铵，适当提高管式反应器中氨的质量流量和磷酸（体积流量）的比值，适当提高二次氨化量的方法提高磷酸二铵中的氮含量。     

Flight model performance test results of a helium dewar for the soft X-ray spectrometer onboard ASTRO-H

ASTRO-H is a Japanese X-ray astronomy satellite, scheduled to be launched in fiscal year 2015. The mission includes a soft X-ray spectrometer instrument (SXS), which contains an X-ray micro calorimeter operating at 50 mK by using an adiabatic demagnetization refrigerator (ADR). The heat sink of the ADR is superfluid liquid helium below 1.3 K. The required lifetime of the superfluid helium is 3 years or more. In order to realize this lifetime, we have improved the thermal performance from the engineering model (EM) while maintaining the mechanical performance. Then, we have performed a thermal test of the flight model (FM). The results were that the heat load to the helium tank was reduced to below 0.8 mW in the FM from 1.2 mW in the EM. Therefore, the lifetime of the superfluid helium is more than 3 years with 30 L of liquid helium.In this paper, the thermal design and thermal test results are described.