国内图书分类号:X703.1 学校代码:10213 国际图书分类号:628.1 密级:公开
工学博士学位论文
载人航天器中冷凝水的深度处理
技术研究
博士研究生:金大瑞
导 师:尤 宏 教授
申请学位:工学博士
学科:环境科学与工程
所在单位:市政环境工程学院
答辩日期:2010年11月
授予学位单位:哈尔滨工业大学
Classified Index: X703.1
U.D.C: 628.1
Dissertation for the Doctoral Degree in Engineering
ADVANCED TREATMENT OF HUMIDITY
CONDENSATE IN MANNED SPACECRAFT
Candidate:Jin Da-Rui
Supervisor:Prof. You Hong
Academic Degree Applied for:Doctor of Engineering
Speciality:Environmental Science & Engineering
Affiliation:School of Municipal and Environmental Engineering
Date of Defence:November, 2010
Degree-Conferring-Institution:Harbin Institute of Technology
摘要
摘要
在载人航天领域,航天器生活舱中的冷凝水的深度处理与再利用是解决航天员饮用水供给的有效办法,也是实现长期载人飞行的重要途径。针对现有航天器冷凝水处理工艺存在的不足,以及在航天器微重力环境下常规处理工艺很难有效的应用在冷凝水处理中的缺点,对冷凝水的深度处理进行了探索性的研究。依据航天器内的环境特点及冷凝水的水质特性,提出一种采用湿式氧化-离子交换-消毒组合工艺的方式深度处理冷凝水的技术路线。
在湿式氧化单元中,研制了一种全新的无泡供氧湿式氧化反应器,该反应器中氧气透过膜以无泡的形式进入到催化固定床内在催化剂的作用下催化降解冷凝水中的污染物,避免了微重力下的气液难以分离的问题。研究了无泡供氧湿式氧化反应器对冷凝水中主要污染物乙醇的催化降解能力。研究表明,在常温常压下,采用中空纤维膜组件和平板膜组件的反应器对乙醇均有较高的催化降解效率,当供氧压力不大于膜泡点时,提高供氧压力有助于提高乙醇的去除率。随着停留时间的延长,乙醇的去除率和完全氧化率均提高,副产物的产率也随之降低,膜供氧传质效率的提高有助于提高催化反应程度。采用不同膜组件的反应器均可使冷凝水中乙醇的去除率达到90%以上。由于中空纤维膜在反应器内可均匀分布,相比
采用平板膜有着更大的有效供氧面积,因而在催化降解乙醇方面,采用中空纤维膜供氧的无泡供氧湿式氧化反应器有着更高的催化降解效率。
采用浸渍还原法研制出一种高活性铂催化剂。所制备的催化剂可在常温常压以氧气为催化剂的条件下催化降解乙醇,考察了影响催化剂活性的因素,优化了催化剂的制备工艺,对其进行了结构表征。研究表明,相比其它载体,以活性炭为载体的Pt/AC对乙醇有更好的催化降解性能。通过对催化剂进行XRD、XPS和SEM表征发现,Pt/AC中活性组分Pt是以单质形态存在的,且具有较高的分散度。活性炭载体通过双氧水改性处理后,Pt/AC催化性能得到了显著的提高,表明载体表面的含氧基团含量对催化剂活性有着明显的影响。
在离子交换单元中,研究了十种离子交换树脂对乙醇催化副产物乙酸的交换吸附能力。结果表明,IRA67树脂对于乙酸的交换吸附要强于其它种离子交换树脂,能有效地将废水中乙酸吸附分离。乙酸在该树脂上的交换吸附是一个放热过程。IRA67树脂的各温度离子交换吸附等温线符合H3型等温线特点,其对乙酸的交换吸附规律可用Langmuir方程描述,IRA67离子交换树脂对乙酸
哈尔滨工业大学工学博士学位论文
的饱和交换量约为75m g·g-1。
在消毒单元中,采用聚碘树脂对经过湿式氧化单元、离子交换单元处理后的冷凝水进行消毒。考察了四种聚碘树脂的杀菌性能,并对聚碘树脂的杀菌机理及稳定性进行了分析。结果表明,202聚碘树脂具有较强的杀菌能力,在与水接触时间为10s时,就可使出水中的菌落总数和总大肠菌达到饮用水标准,同时出水中的余碘浓度小于2mg·L-1。考察了pH值、温度、接触时间等因素对202聚碘树脂的碘流失的影响,结果表明202聚碘树脂在pH值为4-8,温度在50℃以下的条件下具有良好的稳定性。
建立了一套采用湿式氧化-离子交换-消毒组合工艺处理冷凝水的反应器,考察了其对冷凝水中主要污染物乙醇去除效果,同时考察了对水中的细菌杀灭效果和设备长期运行的稳定性。结果表明,在当进水流量为5mL·min-1,供氧压力5kPa的运行条件下,可有效去除水中的乙醇及乙醇氧化的副产物乙酸,同时出水中的菌落总数和总大肠菌达到饮用水标准,通过连续运行试验发现,反应器具有良好的运行稳定性和可靠性。
关键词:膜供氧;湿式氧化;冷凝水;乙醇;载人航天器
Abstract
Abstract
Treatment and reuse of humidity condensate is a feasible way to supply potable wate in manned spac
ecraft and is a crucial component of the manned space exploration program for extended duration in the environment of space. Based on the inherent shortcomings of currently available technology in treating humidity condensate and the conventional treatment technologies are hardly used in treating humidity condensate in the microgravity environment of manned spacecraft, Exploratory study was done in treating humidity condensate. Based on the characteristics of special environment and humidity condensate, a composite technology of wet oxidation-ion exchange-disinfection was investigated in treating humidity condensate in this paper.
In the wet oxidation unit, a new type of catalytic reactor, membrane aeration wet oxidation reactor was studied. In the reactor, a membrane module was employed, and the membrane module acted as a membrane bubbleless aerator. Oxygen permeated the membrane module into the reactor, and reacted with organic contaminants in humidity condensate catalyzed by Pt catalyst. The difficult problem of gas-liquid separation in the microgravity environment was avoiding. The removal rate of ethanol in humidity condensate was studied under various reaction conditions using the reactor. It was found that the removal rate of ethanol increasing when the membrane aeration pressure increased, and the removal rate of ethanol increased and the generation rate of acetic acid decreased as the liquid hydraulic retention time increased, and the the mass transfer coefficient had a deep influence on cata
lytic reaction. The removal rate of ethanol in humidity condensate was above 90% after being treated by the reactor. Because of the well-distributed of hollow fibre membrane in the reactor, the treatment efficiency of the reactor using hollow fibre membrane was higher than the reactor using flat membrane in treating ethanol in humidity condensate.
The coating-type Pt catalysts were prepared by the method of impregnation reduction, and the catalysts were used in catalytic degradation of ethanol which was the main contaminant in humidity condensate. The factors that affected the activity of the catalysts were studied, then the preparing process of the catalysts was
max中reactor
版权声明:本站内容均来自互联网,仅供演示用,请勿用于商业和其他非法用途。如果侵犯了您的权益请与我们联系QQ:729038198,我们将在24小时内删除。
发表评论