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1.
橡胶衬里是采用一定厚度的耐蚀橡胶复合在基体表面,形成连续完整的覆盖层,以隔离腐蚀介质,达到防腐蚀的目的。橡胶衬里具有防腐蚀性能可靠、使用寿命长、造价低、现场施工方便、技术易掌握等优点。传统的橡胶衬里工艺是在设备上贴衬未硫化橡胶后,在硫化罐内利用高温高压蒸气进行硫化。由于受硫化罐体积的限制,这种工艺只适用于小型工件和设备的橡胶衬里。为了满足生产发展的需要,近年来国内外相继开发了适用于大型设备(如贮罐等)的各种新型橡胶品种及硫化工艺,使橡胶衬里走出了硫化罐的狭小范围,而得到了广泛的推广和应用。本文将…  相似文献   

2.
以高密异收缩涤纶复合丝织物、3M气溶胶和聚四氟乙烯(PTFE)微孔膜为基材,通过层压来制备防水透湿层压复合织物,并对复合织物的剥离强力等性能进行测试,探索出复合织物的最优工艺。实验结果表明,不同的层压工艺对层压织物的剥离强力产生很大的影响,特别是上胶量。随着上胶量的增大,层压织物的剥离强力而增大,但增大到一定程度时不能完全剥离;而透湿性、柔软性变得较差;当热压温度为100℃,热压压力为0.3MPa,上胶量为31.8g/m~2时,防水透湿层压复合织物的性能较优,透湿量为5010g/(m~2·24h),弯曲刚度(B)达到0.2833N/(m~2·cm),滞后矩(2HB)达到0.1132N·cm/cm。  相似文献   

3.
化工设备图形符号标准化的探讨王小玲(武汉纺织工学院)一、化工设备图形符号使用现状在化工过程开发、化工工艺设计以及化工工艺等学科的教学、科研中,都不可避免地要绘制或阅读生产工艺流程图。这是一种以图解方式表达原料如何依次通过各种化工过程和设备从而转变为产...  相似文献   

4.
在商用飞机复合材料结构制造过程中,可剥布在复合材料共胶接和二次胶接的表面处理过程中应用越来越广泛,逐步替代传统打磨方式。然而在实际应用中,可剥布与复合材料树脂体系之间存在一定的匹配性,经不同可剥布处理后的复合材料表面胶接性能存在较大差异。为研究其对胶接性能的影响,选用四种航空用可剥布对复合材料进行表面处理,采用热压罐工艺制备T300/Cycom 970环氧复合材料层压板,选取同一种航空用胶膜进行胶接。按照ASTM剥离测试和单搭接剪切测试标准,对T300/Cycom 970环氧复合材料胶接结构的性能进行测试,采用接触角测试、SEM和X射线能谱测试(XPS)分别对复合材料层压板制件和可剥布织物的表面润湿性、表面形貌和表面元素进行测试与分析。结果表明:选用聚酯湿可剥布处理后的T300/Cycom 970环氧复合材料胶接性能最佳;可剥布织物及涂层的残留会影响复合材料胶接性能;可剥布处理能改善复合材料表面润湿性,提高表面能,但并不能保障胶接质量;可剥布编织形式直接影响复合材料表面形貌,决定其表面粗糙度,对复合材料胶接性能也有较大的影响。  相似文献   

5.
对化工设备故障发生规律必要性进行了分析,对化工设备投运初期的设备内在质量、安装质量、工艺布置,设备正常运转中期故障发生因素、设备运转后期常发生故障和规律进行了研究。阐述了化工设备故障诊断可靠性分析方法并提出了故障预防及维修控制措施。  相似文献   

6.
天然橡胶和常用合成橡胶若不经硫化处理,其理化指标和机械性能低劣,不能用于化工防腐.一旦硫化,大分子间产生一定程度的"钩链"后,各项性能均可发生变性的变化,机械和化学稳定性性能优异.与树脂防腐、衬铅防腐等相比,衬胶设备增重少,施工环境良好、无毒、操作简便,更因作化工衬里耐腐蚀性能好而日益受到重视. 衬胶防腐的关键工艺是硫化.经典的硫化方法一般是在硫化釜内用3~4kg/cm~2  相似文献   

7.
近年来,我国化工行业向着大规模不断的发展,引进先进的生产设备,使现在的生产装置规模化,大型化。也正因为如此,生产能力也会进一步的提高,单线的工艺产能不断扩大,因此,为适应化工设备的发展,与化工设备密切相关的方面也应根据需要进行适当调整以及改进。本文介绍了几种化工设备的局部设计形式,并对设备结构设计及选材进行分析,并在此基础上介绍如何优化设备结构设计以及选材。  相似文献   

8.
气流粉碎机高分子材料内衬制作工艺探讨   总被引:2,自引:0,他引:2  
气流粉碎机是现代精细化工生产中使用的一个重要设备,传统的的气流粉碎机内衬主要是采用耐磨金属和工程陶瓷作为衬里.本文中对使用高分子材料作为衬里的制造工艺进行了较详尽的阐述,为气流粉碎机的改进和更新提出了一条较为先进的途径.  相似文献   

9.
引言 水喷射泵是用水做工作介质,它具有压缩比大,直接对大气排气并能抽除含有灰尘或腐蚀性气体等特点。在轻工、化工、医药和食品等工业部门得到广泛利用。喷射水亦可用来冷凝蒸汽,使工艺流程和设备大大简化,而且成本低,操作简便,易于维修。 在制胶工业中,采用水喷射泵,对淡胶液蒸发后产生的气体进行冷凝和抽吸,从而达到胶液增浓的目的。由于设计、制造、安装、操作等方面存在的问题,水喷射泵在工作中常发生“倒水”、“跑胶”、“真空抽吸效果差”等故障。 一、常见故障的成因及排除方法 水喷射泵在工作中的常见故障及产生原因、排除方法,…  相似文献   

10.
在化工生产中,由于工艺的需要,在流程中往往存在着各种不同的换热过程,换热器就是用来进行此项热传递过程的设备,它可以使热量从温度较高的流体传递给温度较低的流体,以满足工艺的需要。换热器的稳定运行在工艺生产中起着相当重要的作用,一旦泄漏会严重影响工艺生产,造成两种流体混合,导致不安全因素的产生。本文主要探讨炼油化工设备换热器的密封泄漏问题及处理措施。  相似文献   

11.
Biosorption of chromium and zinc ions by an industrial algal waste, from agar extraction industry has been studied in a batch system. This biosorbent was compared with the algae Gelidium itself, which is the raw material for agar extraction, and the industrial waste immobilized with polyacrylonitrile (composite material). Langmuir and Langmuir-Freundlich equilibrium models describe well the equilibrium data. The parameters of Langmuir equilibrium model at pH 5.3 and 20 degrees C were for the algae, q(L)=18 mg Cr(III)g(-1) and 13 mgZn(II)g(-1), K(L) = 0.021l mg(-1)Cr(III) and 0.026l mg(-1) Zn(II); for the algal waste, q(L)=12 mgCr(III)g(-1) and 7mgZn(II)g(-1), K(L)=0.033lmg(-1) Cr(III) and 0.042l mg(-1) Zn(II); for the composite material, q(L) = 9 mgCr(III)g(-1) and 6 mgZn(II)g(-1), K(L)=0.032l mg(-1)Cr(III) and 0.034l mg(-1)Zn(II). The biosorbents exhibited a higher preference for Cr(III) ions and algae Gelidium is the best one. The pseudo-first-order Lagergren and pseudo-second-order models fitted well the kinetic data for the two metal ions. Kinetic constants and equilibrium uptake concentrations given by the pseudo-second-order model for an initial Cr(III) and Zn(II) concentration of approximately 100 mgl(-1), at pH 5.3 and 20 degrees C were k(2,ads)=0.04 g mg(-1)Cr(III)min(-1) and 0.07 g mg(-1)Zn(II)min(-1), q(eq)=11.9 mgCr(III)g(-1) and 9.5 mgZn(II)g(-1) for algae; k(2,ads)=0.17 g mg(-1)Cr(III)min(-1) and 0.19 g mg(-1)Zn(II)min(-1), q(eq)=8.3 mgCr(III)g(-1) and 5.6 mgZn(II)g(-1) for algal waste; k(2,ads)=0.01 g mg(-1)Cr(III)min(-1) and 0.18 g mg(-1)Zn(II)min(-1), q(eq)=8.0 mgCr(III)g(-1) and 4.4 mgZn(II)g(-1) for composite material. Biosorption was modelled using a batch adsorber mass transfer kinetic model, which successfully predicts Cr(III) and Zn(II) concentration profiles. The calculated average homogeneous diffusivities, D(h), were 4.2 x 10(-8), 8.3 x 10(-8) and 1.4 x 10(-8)cm(2)s(-1) for Cr(III) and 4.8 x 10(-8), 9.7 x 10(-8) and 6.2 x 10(-8)cm(2)s(-1) for Zn(II), respectively, for Gelidium, algal waste and composite material. The algal waste has the lower intraparticle resistance.  相似文献   

12.
The reaction of (η(5)-C(5)H(5))Co(PPh(3))(2) with 1,3-bis(isopropyl)imidazol-2-ylidene (Im(i)Pr(2)) leads to the formation of (η(5)-C(5)H(5))Co(PPh(3))(Im(i)Pr(2)). In a similar fashion (η(5)-C(5)H(5))Co(Im(i)Pr(2))(CO) is formed from (η(5)-C(5)H(5))Co(CO)(2). The barrier to rotation about the Co-C(carbene) bond in the latter complex has been determined by variable-temperature (1)H NMR spectroscopy (13.6 kcal/mol) and by computation (13.3 kcal/mol). The structural and dynamic properties of (η(5)-C(5)H(5))Co(ImMe(2))(CO) (ImMe(2) = 1,3-dimethylimidazol-2-ylidene) and (η(5)-C(5)H(5))Co(ImAr(2))(CO) (ImAr(2) = 1,3-dimesityl-2-ylidene) were examined by quantum chemistry calculations.  相似文献   

13.
Treatment of the diazametallacycle Cp(2)Zr(N(t-Bu)C=N(SiMe(3))N(SiMe(3))) (4a) with diphenylacetylene resulted in the formation of the azametallacyclobutene Cp(2)Zr(N(t-Bu)C(Ph)=C(Ph)) (6a) and Me(3)SiN=C=NSiMe(3) in high yield. A kinetic study using UV-vis spectroscopy was carried out on the transformation. Saturation kinetic behavior was observed for the system, which is supportive of a mechanism that involves a reversible formal [2 + 2] retrocycloaddition of 4a to generate the transient imido species Cp(2)Zr=N-t-Bu (7a) and Me(3)-SiN=C=NSiMe(3). Trapping 7a with diphenylacetylene in an overall [2 + 2] cycloaddition reaction affords zirconacycle 6a. The study of cycloreversion/cycloaddition reactions between diazametallacycle complexes and diphenylacetylene was extended to other zirconocene systems. Detailed kinetic studies were performed for the exchange reactions between the diazametallacycle complexes Cp(2)Zr(N(2,6-Me(2)Ph)C=N(SiMe(3))N(SiMe(3))) (8a) and Cp(2)Zr-(N(2,6-Me(2)Ph)C=N(t-Bu)N(t-Bu)) (8b) with diphenylacetylene (5a) to give the corresponding azametallacyclobutene complex Cp(2)Zr(N(2,6-Me(2)Ph)C(Ph)=C(Ph)) (6c) and extruded carbodiimides (Me(3)SiN=C=NSiMe(3) for 8a and (t-Bu)N=C=N(t-Bu) for 8b). For both systems, the reactions were found to be first order in metallacycle and zero order in alkyne. Treatment of the diazametallacycle complexes Cp(2)Zr(N(2,6-i-Pr(2)Ph)C=N(Cyc)N(Cyc)) (9a) and Cp(2)Zr-(N(2,6-i-Pr(2)Ph)C=N(i-Pr(2))N(i-Pr(2))) (9b) with alkyne 5a resulted in the formation of the six-membered zirconacycles 10a,b, respectively, upon heating at 75 degrees C. The products 10a,b are generated from the overall insertion of alkyne 5a into the nitrogen-carbon bond of the zirconium-containing diazacyclobutane. Complex 10a has been characterized by an X-ray crystallographic study. When the azacyclobutene Cp(2)Zr(N(2,6-i-Pr(2)Ph)C(Ph)=C(Ph)) (6e) was treated with CycN=C=NCyc or (i-Pr)N=C=N(i-Pr), the same six-membered zirconacycle complexes 10a,b were obtained. Kinetic analysis of the reaction of 6e and (i-Pr)N=C=N(i-Pr) to yield 10b supports an associative process wherein alkyne 5a directly inserts into the zirconium-carbon bond of 6e. The diazametallacycle complex 4a underwent a stoichiometric metathetical exchange with symmetrical carbodiimides RN=C=NR (R = p-Tol, m-Tol, i-Pr, Cyc) to generate new cyclic zirconocene complexes and Me(3)SiN=C=NSiMe(3). Kinetic studies were carried out on the exchange reaction between 4a and (m-Tol)N=C=N(m-Tol) to form 4e and Me(3)SiN=C=NSiMe(3). The experimental rate data obtained are consistent with a dissociative mechanism. Additionally, the saturation rate constant derived for this system from the data is the same (within experimental error) as the saturation rate constant obtained from the kinetic study of 4a and diphenylacetylene to form 6a and Me(3)SiN=C=NSiMe(3). These findings provide additional support for a dissociative mechanistic pathway in the exchange reactions, since the rate constant in the formal [2 + 2] retrocycloaddition reaction to generate imidozirconocene species Cp(2)Zr=N-t-Bu (7a) and Me(3)SiN=C=NSiMe(3) should be the same for both reactions.  相似文献   

14.
The waste distillery sludge from sugar-cane industry was pretreated physically (boiled, heated and autoclaved) as well as chemically (HCl, H(2)SO(4), H(3)PO(4), NaOH, Ca(OH)(2), Al(OH)(3), C(6)H(6), HCHO, CH(3)OH and C1(2)H(25)OSO(3)Na (sodium dodecyl sulphate (SDS)) for assessing the comparative sorption capacity of untreated and modified distillery sludge for Pb(II) biosorption from aqueous solutions. Experiments were conducted in shake flasks on a batch basis to access the effect of different experimental parameters such as pH, biosorbent dosage, biosorbent size, initial Pb(II) concentration and contact time. The uptake capacity 'q' (mg/g) of untreated and pretreated distillery sludge was in following order: NaOH (51.29+/-1.21)>HCl (49.82+/-1.22)>HCHO (49.56+/-1.14)>H(2)SO(4) (47.71+/-1.20)>HgCl(2) (45.32+/-1.06)>Ca(OH)(2) (44.01+/-1.18)>MeOH (43.73+/-1.23)>C(6)H(6) (42.72+/-1.19)>H(3)PO(4) (42.01+/-1.17)>SDS (40.87+/-1.27)>autoclaved (40.23+/-1.24)>Boiled (39.95+/-1.19)>heated (38.87+/-1.32)>Al (OH)(3) (38.30+/-1.14)>untreated (37.76+/-1.21). In further parameter studies, the optimized biosorbent size was 0.250 mm at pH 5 and best dose was 0.05 g of biosorbent. The applicability of the Langmuir and Freundlich models for sorption process was tested and best fitted model was Langmuir with the coefficient of determination (R(2)) value, 0.97, the process followed second order kinetic mechanism.  相似文献   

15.
A series of CeO(2)-ZrO(2) mixed oxides were prepared using coprecipitation method and characterized by BET, oxygen storage capacity (OSC), X-ray diffraction (XRD) and H(2)-temperature-programmed reduction (H(2)-TPR). The catalytic activities toward toluene combustion were investigated in a micro-reactor. The results demonstrate that the catalytic activity of Pt/gamma-Al(2)O(3)/Ce(0.50)Zr(0.50)O(2) monolithic catalyst can be greatly improved by doping metal into Ce(0.50)Zr(0.50)O(2). When doping Y and Mn into Ce(0.50)Zr(0.50)O(2) simultaneously, the catalyst Pt/gamma-Al(2)O(3)/Ce(0.40)Zr(0.40)Y(0.10)Mn(0.10)O(X) shows the highest activity. The T(10) (the temperature of 10% toluene conversion) and the complete conversion temperature (the temperature of 90% toluene conversion) of toluene are 443 and 489K, respectively. Gas hourly space velocity (GHSV) results show that the prepared catalyst can be applied in a wide range of GHSV (from 12,000 to 20,000h(-1)). The catalyst prepared shows great potential for practical application.  相似文献   

16.
The presence of Fe(3)O(4)-CoO/Al(2)O(3) can improve degradation efficiency significantly during the ozonation of the herbicide 2-(2,4-dichlorophenoxy) propionic acid (2,4-DP). The main factors affecting degradation efficiency, such as pH, the catalyst concentration and addition of the scavenger, were investigated. The kinetics of the catalytic ozonation are also discussed. The results indicate that two factors, the oxidation after adsorption of 2,4-DP and the oxidation of hydroxyl radicals (OH), lead to a great enhancement in ozonation efficiency during the catalytic ozonation of 2,4-DP in the presence of Fe(3)O(4)-CoO/Al(2)O(3), in which the oxidation of the OH plays an important role. Under controlled conditions, the apparent reaction rate constants for the degradation of 2,4-DP were determined to be 2.567 × 10(-4)s(-1) for O(3) and 1.840 × 10(-3)s(-1) for O(3)/Fe(3)O(4)-CoO/Al(2)O(3). The results from the analysis of the reaction kinetics using the relative method showed that O(3)/Fe(3)O(4)-CoO/Al(2)O(3) possessed a larger R(ct) (R(ct) is defined as the ratio of the ·OH exposure to the O(3) exposure, R(ct) = ∫C(t)(OH) dt/C(t)O(3)dt) than O(3), indicating that O(3)/Fe(3)O(4)-CoO/Al(2)O(3) produced more hydroxyl radicals.  相似文献   

17.
Four quanternary Zr-based bulk metallic glasses(BMGs)were selected,including the Zr_(46)Ti_2Cu_(45)Al_7,Zr_(61)Ti_2Cu_(25)Al_(12),Zr_(55)Ti_4Ni_(22)Al_(19)and Zr_(55)Ti_2Co_(28)Al_(15),due to their robust glass-forming ability and containing a single species of late transition metal(LTM)in compositions.Their pitting resistances in 0.6 M Na Cl aqueous solution were investigated to examine the role of LTM elements in the alloys,with electrochemical measurements,surface morphology observation and x-ray photoelectron spectrometry analysis.It is shown that in comparision with two Cu-bearing BMGs,Zr_(55)Ti_4Ni_(22)Al_(19)and Zr_(55)Ti_2Co_(28)Al_(15)BMGs exhibited significantly superior resistance to pitting.Zr_(61)Ti_2Cu_(25)Al_(12),Zr_(55)Ti_4Ni_(22)Al_(19)and Zr_(55)Ti_2Co_(28)Al_(15)BMGs manifested distinct passivation behaviour,because of the formation of surface passive film mainly comprising of Zr O_2,Ti O_2and Al_2O_3.However,no significant differences in the electrochemical resistive properties and thicknesses of passive films were found between Zr_(61)Ti_2Cu_(25)Al_(12)and Zr_(55)Ti_4Ni_(22)Al_(19)BMGs.Nevertheless,at the passive film/metal interface,copper enrichment took place in Zr_(61)Ti_2Cu_(25)Al_(12),whereas the nickel was slightly deficient at the interface in Zr_(55)Ti_4Ni_(22)Al_(19).During pitting propagation,selective dissolution of the zirconium,titanium and aluminum over the copper took place in Zr_(61)Ti_2Cu_(25)Al_(12),but it was not the case in Zr_(55)Ti_4Ni_(22)Al_(19).For the two Cu-bearing BMGs,reduction of passive base metal elements in composition resulted in local selective dissolution,even absence of the passivation.  相似文献   

18.
Physicochemical and bacteriological status of a local textile mill effluent showed considerably high values of temperature (40 degrees C), pH (9.50), EC (3.57mus/m), BOD (548mgl(-1)), COD (1632mgl(-1)), TSS (5496mgl(-1)), TDS (2512mgl(-1)), heavy metals ions (0.28-6.36mgl(-1)) and color above the prescribed fresh water limits. However, a considerable decline in almost all pollution indicators from source to sink indicated signs of natural remediation. Ten bacteria strains isolated from effluent showed comparatively higher resistance (MRL) (mgl(-1)) (average) for 10 heavy metals than against four structurally different dyes tested on solid media of mineral salt. Overall bacterial resistance was quite high against Fe(3+) (2820), Cr(3+) (1203), Zn(2+) (1122), Mn(2+) (804) and Pb(2+) (435), whereas, it varied amid 300-500 in four dyes. Bacterial decolorization/degradation of dyes indicated on solid media was confirmed through experiments carried out in liquid broth.  相似文献   

19.
Chang M  Tie S 《Nanotechnology》2008,19(7):075711
A novel polychromic phosphor with core-shell heteronanostructure has been prepared to improve the chromatic index of phosphors. As for the first example, Y(2)O(3):Eu(3+)@SiO(2)@YVO(4):Eu(3+), its synthetic route, structure and optical properties are presented in this paper. X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), high resolution transmission electron microscopy (HR-TEM), energy-dispersive x-ray spectra (EDS) and photoluminescence (PL) were all employed to characterize the composite core-shell phosphors. The XRD, FE-SEM and HR-TEM results indicate that the SiO(2) and YVO(4):Eu(3+) layers have been successfully coated on Y(2)O(3):Eu(3+) nanoparticles and SiO(2) layer, respectively: these layers were further verified by the EDS. The PL showed that the red-emitting phosphor Y(2)O(3):Eu(3+)@SiO(2)@YVO(4):Eu(3+) possessed the independent luminescent properties of both the core Y(2)O(3):Eu(3+) and the shell YVO(4):Eu(3+). The emissions were dominated by [Formula: see text] or [Formula: see text] transitions of Eu(3+) when excited with different wavelengths. Since this broad-band response to excitation in the range of 225-340?nm gave more red/dark red emissions found at 612, 616 and 620?nm, the novel phosphor Y(2)O(3):Eu(3+)@SiO(2)@YVO(4):Eu(3+) could have potential biological labeling applications with wide flexibility.  相似文献   

20.
SiO(2) pillared layered titanate (SiO(2)-H(2)Ti(4)O(9)) was prepared via intercalating organosilanes into the interlayers of the layered K(2)Ti(4)O(9) followed by calcination at 500 degrees C. The resulting materials were characterized using XRD, N(2) adsorption-desorption isotherms, UV-vis spectra, IR spectroscopy and Raman spectroscopy. The photocatalytic activity of SiO(2)-H(2)Ti(4)O(9) was evaluated by photocatalytic degradation of aqueous methylene blue dye (MB). XRD and specific surface area results showed that SiO(2)-H(2)Ti(4)O(9) had an interlayer distance of 1.45 nm and a specific surface area of 148 m(2)g(-1). UV-vis absorption spectrum of SiO(2)-H(2)Ti(4)O(9) showed a red shift, indicative of a narrower band gap compared to K(2)Ti(4)O(9). In addition, SiO(2)-H(2)Ti(4)O(9) showed higher MB adsorption capacity compared to H(2)Ti(4)O(9) and K(2)Ti(4)O(9). MB photodegradation over H(2)Ti(4)O(9), K(2)Ti(4)O(9) and SiO(2)-K(2)Ti(4)O(9) followed zero-order kinetics under our experimental conditions, and the photocatalytic activity of SiO(2)-H(2)Ti(4)O(9) was found to be three times higher than that of K(2)Ti(4)O(9), which could be attributed to the increase of interlayer space and specific surface area of SiO(2)-pillared layered titanate.  相似文献   

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