共查询到20条相似文献,搜索用时 93 毫秒
1.
2.
3.
4.
钙矾石对水吸附热力学及吸附机理研究 总被引:1,自引:0,他引:1
用微电子热天平测定了钙矾石对水吸附的等温线,求出不同覆盖率时的吸附热及Freundlich等温吸附经验式Г=kp^n中的经验常数n,并对吸附机理进行探讨。发现存在配位场力,氢键力和Van der Waals力共三种吸附力。 相似文献
5.
6.
针对低温条件下SO2对Ca(OH)2吸收NO的影响进行了实验研究,分析了烟气中O2和H2O对SO2促进Ca(OH)2吸收NO的影响。实验结果表明,当烟气不含SO2时,Ca(OH)2对NO基本无吸收作用;烟气中SO2的存在对NO吸收具有促进作用。H2O和O2对SO2促进NO吸收有显著影响;当烟气不含O2时,即使大量的SO2被吸收,NO吸收效率仍较低;只有SO2与O2和H2O共存才能促进NO吸收。脱硫产物CaSO3对NO无氧化作用;NO、H2O和SO2未在吸收剂表面产生可分解释放NO2的大分子中间配合物。分析认为在脱硫过程中产生了可以促进NO与O2反应的非稳定中间活性组分。 相似文献
7.
将经历多次循环后失活的钙基吸收剂置于环境中吸水自活化,通过XRD分析了自活化过程吸收剂物相演变规律,在双固定床反应器系统上分析了吸水率对失活钙基吸收剂循环捕集CO2性能的影响规律, 通过SEM和N2吸附分析了自活化提高钙基吸收剂循环碳酸化转化率的机理。结果表明:失活钙基吸收剂首先吸收环境中水分生成Ca(OH)2,当吸水率达到100%后继续吸水生成Ca(OH)2?2H2O,自活化极限为170%;自活化可以提高失活钙基吸收剂循环碳酸化转化率,自活化后钙基吸收剂循环捕集CO2性能与吸水率呈线性比例关系,重复自活化可再次提高吸收剂循环碳酸化转化率;自活化过程中,失活钙基吸收剂颗粒表面重新生成孔隙,比孔容和比表面积增加,有利于吸收剂中CO2的扩散,因此自活化后钙基吸收剂循环捕集CO2性能提高。 相似文献
8.
粉煤灰改性钙基脱硫荆技术中,加入硫酸盐能显著提高脱硫荆的比表面积。本文考察了Na2SO4、MgSO4、CaSO4三种常见硫酸盐在三种不同物料配比下对钙基脱硫剂比表面积的提高作用。结果表明:加入硫酸盐能进一步大幅提高钙基脱硫剂比表面积。三种硫酸盐作用效果依次为NaSO4〉MgSO4〉CaSO4。 相似文献
9.
10.
铌锌酸铅基陶瓷相变的热力学分析 总被引:1,自引:0,他引:1
PZN基陶瓷在烧结过程中都要经历由焦绿石相朝钙钛矿相的转变。PZN基陶瓷中钙钛矿相含量的多少与添加剂的种类及数量密切相关,本工作根据化学热力学理论,讨论了内应力对化学势的影响,建立了一个热力学模型,并用该模型讨论了PZN基陶瓷在烧结时的相变过程。 相似文献
11.
As a clean, free, and nondepleting source, solar energy has become the focus of increasing attention in the drying industry. A lignite-fired power plant integrated with a solar dryer (LPPS), in which solar energy is used to dry lignite and the predried lignite is used to generate electricity, is analyzed theoretically in this paper. The aim of this study is to evaluate the energy performance of solar drying under different system parameters. Thermodynamic models, with which the second-law efficiency of the LPPS could be maximized, were developed. A reference case with three kinds of lignite as input fuel was analyzed to quantify the system performance. The first-law and second-law efficiencies were obtained. The solar-to-electric conversion efficiency in the LPPS is more than 34%. Therefore, solar drying is a potential technology that should be promoted in lignite-deposited areas. Moreover, the influence of main parameters on the performance of system was analyzed. Dryer efficiency is determined to have significant influence on the solar-to-electric conversion efficiency. 相似文献
12.
13.
提出了一种应用钙基脱硫剂脱除冶炼烟道气中高浓度SO2并回收硫单质的方法。通过热力学模拟多种硫化物与SO2之间的反应,筛选得出硫化钙(CaS)适合作为化学链脱硫技术的脱硫剂,它在400~650℃范围内可将SO2还原为单质硫,生成的固相产物为CaSO4而非CaO。通过固定床反应器内的脱硫实验,发现温度对脱硫率和硫单质回收率影响较大。在400~650℃范围内温度越高,脱硫率和硫单质回收率越大;当温度高于600℃时,脱硫率和硫单质回收率基本相等。提高空速,则会降低脱硫率和硫单质回收率,但两者的差值随空速增大逐渐减小。当烟气中SO2浓度小于1%时,脱硫率维持在99.8%基本不变;SO2浓度升至3.45%后,平均脱硫率急剧下降至92.1%;SO2浓度越高,平均脱硫率越低。硫单质回收率随SO2浓度增大存在一最佳范围。在脱硫反应后期,粒径较大的脱硫剂颗粒脱硫性能较低。SEM照片表明了脱硫剂颗粒随反应温度的升高团聚现象更为明显,XRD表征证明了反应中SO2气体被还原为升华硫颗粒。 相似文献
14.
Na Wang Xin Huang Hao Gong Yanan Zhou Xin Li Fei Li Ying Bao Chuang Xie Zhao Wang Qiuxiang Yin Hongxun Hao 《American Institute of Chemical Engineers》2019,65(5):e16570
The thermodynamic mechanism of selective cocrystallization was investigated by combination of molecular dynamics (MD) simulations and phase diagram analysis, using system of urea and cresol isomers as model compounds. Hansen solubility parameters (HSPs) models were utilized to predict miscibility and cocrystal formation. Thermodynamic phase diagrams of cresol isomers and urea were measured with the help of process analysis technology. MD simulations were performed to investigate the intermolecular interactions between m- and/or p-cresol and urea, by calculating the solvation free energies (SFEs) and analysing radial distribution functions (RDFs). The simulation and experimental results indicate that the solubility data of urea are apparently affected by the SFEs, which are linearly related with the concentration of urea. Moreover, it was also found that the type of O-H···O=C hydrogen bond plays a critical role in the contribution of intermolecular interactions and is also a key factor for selective cocrystallization. 相似文献
15.
为了分析钙基吸收剂硫氮协同脱除过程中产物层的生长机制,采用氢氧化钙单晶体表面(0001)模拟吸收剂孔隙的孔壁及外表面,针对脱硫、脱硝及硫氮协同脱除过程中产物层的生长规律进行了分析,结合晶体生长理论及脱硫和脱硝过程中产物层生长的差异,提出了硫氮协同脱除过程中产物层生长的机制。研究结果表明,脱硫反应首先发生在单晶表面局部区域,并使该区域膨胀形成颗粒状凸起结构;之后,随着反应区域不断扩大,表面膨胀趋于一致,从而形成连续致密产物层。由于脱硝产物易溶于水,且在液膜中扩散,因此脱硝反应对单晶表面表现出刻蚀作用。硫氮协同脱除过程中,脱硝反应的刻蚀作用抑制了脱硫连续致密产物层的形成,同时,液膜中脱硝产物的出现也改变了脱硫产物的生长习性,因此反应后产物层为疏松结构。 相似文献
16.
17.
The oxidation of propane has been investigated in the presence and absence of tetrachloromethane (TCM) on calcium hydroxyapatite
(CaHAp), Ca3(PO4)2, CaSO4 and CaO at 723 K. In the absence of TCM, the conversion of C3H8 on CaHAp was 7.7–9.2% during 6 h on-stream while that on Ca3(PO4)2, CaSO4 and CaO was 0.6, 0 and 0.2–0.4%, respectively. The principal products on all catalysts in the absence of TCM were CO and
CO2 with small selectivities to C3H6 and C2H4 (both 5–6%) observed on CaHAp. Upon addition of TCM, the selectivity to C3H6 on all catalysts and the conversion of C3H8 on CaSO4 increased while, with increasing time-on-stream, the changes in the conversion and selectivity were dependent upon the nature
of the catalysts. XPS and XRD analyses provide evidence for the presence of chlorine in the surface and/or bulk of three of
the catalysts, suggesting that chlorinated species on the solids play a role in the selectivity enhancement, but the absence
of chlorine from the sulphate demonstrates the dissimilarities of the catalysts in their abilities to sorb and decompose TCM.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
18.
19.
化石燃料火电厂排放的CO2约占全球CO2总排放量的1/3,采用化学吸附法直接脱除高温烟气中的CO2既可以减少系统的能量损失又可以保护环境。文中采用机械混合法制备金属氧化物掺杂的钙基吸附剂,并以静吸附量和CO2吸附率为评价指标,气相色谱为检测手段,在自制吸附剂评价装置上,研究不同金属氧化物的掺杂对钙基吸附剂吸附性性能的影响。实验表明,掺杂金属氧化物对钙基吸附剂的吸附性能有一定影响,其中质量分数为1%的Li2CO3掺杂的钙基吸附剂的静吸附容量与钙基吸附剂的理论吸附量比较接近,并且优于其他金属氧化物掺杂的钙基吸附剂。 相似文献
20.
对甲酚催化氧化法合成对羟基苯甲醛因其工艺路线简单,是工业上常用方法之一。为了有效利用资源,对对甲酚催化氧化合成对羟基苯甲醛的反应过程进行了较为详尽的热力学分析,对于开发该反应的催化剂和反应工艺具有重要的指导意义。利用热力学原理,首次建立了该反应的焓变和Gibbs自由能变化与反应温度的关系,并计算了反应在不同温度下的平衡常数。经计算得出,该反应的ΔrHβm㈠(298 K)=-387.901 kJ/mol,ΔrGβm㈠(298 K)=-345.875 kJ/mol;在研究温度范围内,该反应为放热反应,且能自发进行。 相似文献