共查询到20条相似文献,搜索用时 62 毫秒
1.
目前在中国南方地区远离天然气长输管线的县城,几乎全部都采用投资建设LNG(液化天然气)气化站,然后通过LNG槽车把LNG运送到LNG气化站,然后经气化后经管道输送到各燃气用户。由于LNG是低温储藏,因此在气化前LNG低温管道需要进行保冷设计。保冷厚度的大小对工艺管道的正常运行起到重要的作用。通过对几种保冷层厚度计算方法的分析,并通过举例说明,对LNG低温管道保冷层厚度的计算方法进行阐述。 相似文献
2.
本文通过计算推导出最佳经济厚度的计算方法,并在通常只考虑热损失和保温结构费用的基础上,同时考虑了运输、安装、损坏、维护、残余价值及各项因素对最佳经济厚度的影响,并推导出计算最佳经济厚度的通用关系式,这样更具有实用性,对实际应用有较好的指导意义。 相似文献
3.
4.
5.
6.
7.
本文从供热管道保温投资效益的角度提出了优化保温层厚度的概念。结合国家最新的保温计算规范,探讨了利用计算机编程优化计算保温层厚度的计算方法,给出了计算机编程计算的计算步骤。这不仅对规划和设计供热管道最佳保温层厚度具有指导意义,而且为利用计算机编程评价供热管道保温的投资经济性和节能效果提供了方向。 相似文献
8.
9.
10.
11.
12.
生物质热解炭化的关键影响因素分析 总被引:2,自引:0,他引:2
《可再生能源》2013,(6):90-95
随着能源消耗需求的增加,气候变化对环境的不利影响等问题的出现,生物质热解炭化技术作为发展可再生能源的重要措施,得到世界范围内越来越多的关注。文章综合分析了生物质原料(种类、粒径、全水分)、热解反应参数(热解温度、升温速率、热解压力、反应气氛、反应时间)以及催化剂等因素对热解炭化过程及产物生物炭的影响,认为目前的热解炭化技术在合理选择工艺参数、能源消耗等方面的研究还不够深入,并提出了相关建议,以期为热解炭化技术的产业化发展提供思路。 相似文献
13.
Kyoung-Hoon Kim Hyung-Jong Ko Kyoungjin Kim Yong-Wook Kim Kie-Joo Cho 《Applied Thermal Engineering》2009,29(10):2072-2079
In this paper heat transfer characteristics and frost layer formation are investigated numerically on the surface of a cryogenic oxidizer tank for a liquid propulsion rocket, where a frost layer could be a significant factor in maintaining oxidizer temperature within a required range. Frost formation is modeled by considering mass diffusion of water vapor in the air into the frost layer and various heat transfer modes such as natural and forced convection, latent heat, solar radiation of short wavelength, and ambient radiation of long wavelength. Computational results are first compared with the available measurements and show favorable agreement on thickness and effective thermal conductivity of the frost layer. In the case of the cryogenic tank, a series of parametric studies is presented in order to examine the effects of important parameters such as temperature and wind speed of ambient air, air humidity, and tank wall temperature on the frost layer formation and the amount of heat transfer into the tank. It is found that the heat transfer by solar radiation is significant and also that heat transfer strongly depends on air humidity, ambient air temperature, and wind speed but not tank wall temperature. 相似文献
14.
15.
A model for the estimation of liquid-hydrogen pressure and temperature along a pipeline equipped with cryogenic insulation is presented together with a numerical simulation scheme and the summary of a sensitivity analysis. 相似文献
16.
17.
18.
19.
In solar ponds, the lower convective layer plays a dual role. It provides a means for the extraction of energy from the pond. It acts also as an in-built seasonal energy store. The ground beneath the pond acts as an additional energy store. To enhance the ground energy storage, a method was earlier proposed by the authors employing trapezoidal-shaped trenches at the bottom of the pond. A rigorous method is presented for the determination of the thickness of the lower convective layer in the case of a flatbottomed pond and the trench depth for a pond with trapezoidal trenches. The energy storage to be provided depends on the magnitude and the pattern of energy extraction. For a constant extraction rate, the required thickness of the lower convective layer or the trench depth increases with an increase in the rate. For a sinusoidal extraction pattern, the thickness or depth increases with an increase in the phase lag of the extraction pattern from the insolation and exhibits a minimum for the amplitude of the extraction pattern for phase lags less than about 95 days. The results also indicate that, for a given heat load (total energy extracted in a year), there exists an area for which the cost of the pond and the associated system for energy utilization is a minimum. 相似文献
20.
填埋场覆盖层甲烷氧化机理及影响因素分析 总被引:2,自引:0,他引:2
我国城市生活垃圾中有机物含量,特别是食品垃圾含量高,垃圾在填埋后会产生大量填埋气(LandfillGas).甲烷是垃圾填埋场释气的主要成分之一,其温室效应作用是CO2的20倍以上.甲烷可以通过多种途径消耗,但通过土壤进行氧化仍是其最为主要和有效的消耗方式.目前国内对这方面的研究比较少.文章主要分析了氧化的机理和土壤温度、含水率、厚度以及含氮量对氧化过程的影响;介绍了国际上在氧化产物上的最新发现,从而为如何调控填埋场覆盖层条件以降低甲烷排放提供一种依据并为氧化产物的研究提供新思路. 相似文献