超临界水氧化技术

超临界水氧化技术是一种很有前途的,以超临界水为反应介质,彻底破坏有机毒害物质的新型环保技术。文章全面综述了超临界水的特征,超临界水氧化的基本原理,工艺流程。着重对超临界水氧化技术存在的问题,如材料的腐蚀和无机盐的沉积进行了讨论,并分析了解决的方法,最后对其应用前景进行了展望。     

超临界水氧化过程中的腐蚀控制方法

超临界水氧化技术(SCWO)是近20 a来发展起来的极具潜力的有机废物处理技术,但该技术存在的设备腐蚀等问题制约着其推广应用。为解决设备腐蚀问题,研究者对SCWO进行了试验与改进。综述了基于解决设备腐蚀问题的SCWO研究进展,并对相关问题进行了讨论。     

超临界水氧化技术工业化的瓶颈问题及解决方法

超临界水氧化技术作为一种绿色环保技术,在处理有毒、难降解和高浓度有害物质上有众多优势,且目前其应用基础已经形成,国外也有实际的工业应用之例。但是超临界水氧化反应器的腐蚀和结垢问题,以及超临界水氧化的高能耗、高费用的问题严重阻碍了该技术在工业生产中的推广和发展,成为制约其工业化的瓶颈问题。本文综述超临界水氧化过程中的反应器的腐蚀和结垢问题、反应热问题,同时指出当前解决这些问题的方法。此外还列举了目前采用超临界水氧化技术的单位以及其所采用的反应器类型。     

含氯介质超临界水氧化过程中几种镍基合金腐蚀的实验研究

超临界水氧化过程中,含氯化合物水溶液对普通不锈钢具有极强的腐蚀性. 使用超临界水氧化反应装置,研究了4种镍基合金不锈钢试样(1Cr18Ni9Ti, 316L, 0Cr18Ni12Ti和QLC12)在超临界水氧化过程中(400~620℃, 28~32 MPa)处理含氯废水时的腐蚀情况. 经过30 d的实验,用金相光学显微镜和扫描电子显微镜观测试样腐蚀的形貌. 结果表明,4种合金在15%(w)含氯水溶液中经过超临界水氧化反应均存在腐蚀. 对腐蚀速率进行了测试,其中1Cr18Ni9Ti和316L腐蚀速率较大,而QLC12腐蚀速率最小,为0.06 mm/a, 可用于制造反应器. 实验发现0Cr18Ni12Ti存在晶间腐蚀现象. 同时对腐蚀机理进行了分析.     

PTA残渣的超临界水氧化处理与资源化利用

介绍了精对苯二甲酸(PTA)残渣的国内外处理情况,提出了利用超临界水氧化技术对PTA残渣进行无害化处理,同时可以回收利用超临界水氧化处理PTA残渣过程中放出的热能,实现PTA残渣的资源化利用,并分析了超临界水氧化技术存在的腐蚀和盐沉积问题。     

超临界水氧化中设备腐蚀及催化剂稳定性研究

研究了超临界水氧化中设备的腐蚀和催化剂的稳定性。以两种不同的催化剂(CuO/Al2O3和MnO2/Al2O3)在不锈钢(1Cr18Ni9Ti)反应器中进行了超临界水氧化偏二甲肼的实验,实验的温度为400～500℃,压力为24～26MPa。结果表明,不锈钢和催化剂在超临界水中都受到不同程度的腐蚀和溶解,腐蚀程度随系统内温度和压力的升高而严重。     

超临界水氧化技术处理难降解有机物的研究进展

超临界水氧化是一种高效处理难降解有机污染物的技术。介绍了超临界水氧化的原理、基础研究及应用研究进展,展望了该技术在处理难降解有机物中的应用前景,并对该技术目前存在的主要问题及解决途径进行了探讨。     

Industrial wastewater oxidation in supercritical water

超临界水氧化技术是一种新型、高效的废物处理技术,在处理有毒、难降解工业废水时有其独特的优势。本文介绍了超临界水氧化技术的基本原理,总结了近几年来国内外超临界水氧化技术处理工业废水的研究进展,分析了该技术存在的技术问题,主要包括腐蚀、盐沉积、高能耗等,并在此基础上提出了相应的解决对策。     

超临界水氧化技术在污泥处理中的应用

超临界水氧化(SCWO)技术是利用超临界水作为反应介质,来破坏有机物质的一种新型氧化技术。文章主要介绍了超临界水的特性和超临界水氧化法的原理以及其在污泥处理中的应用概况。     

超临界水氧化技术的研究与应用进展

超临界水氧化技术是利用超临界水作为反应介质，彻底破坏有机物质的一种新型氧化技术。介绍了超临界水的特性和超临界水氧化的基本原理及反应器装置，综述了超临界水氧化的反应机理、动力学、工程应用，以及有毒有机污染物处理等方面的研究进展。     

Corrosion control methods in supercritical water oxidation and gasification processes

Use of supercritical water (SCW) as a medium for oxidation reactions, conversion of organic materials to gaseous or liquid products, and for organic and inorganic synthesis processes, has been the subject of extensive research, development, and some commercial activity for over 25 years. A key aspect of the technology concerns the identification of materials, component designs, and operating techniques suitable for handling the moderately high temperatures and pressures and aggressive environments present in many SCW processes. Depending upon the particular application, or upon the particular location within a single process, the SCW process environment may be oxidizing, reducing, acidic, basic, nonionic, or highly ionic. Thus, it is difficult to find any one material or design that can withstand the effects of all feed types under all conditions. Nevertheless, several approaches have been developed to allow successful continuous processing with sufficient corrosion resistance for an acceptable period of time. The present paper reviews the experience to date for methods of corrosion control in the two most prevalent SCW processing applications: supercritical water oxidation (SCWO) and supercritical water gasification (SCWG).     

Corrosion resistance of stainless steels in chloride containing supercritical water oxidation system

As the science and process applications of supercritical water (SCW) and supercritical water oxidation (SCWO) become more thoroughly understood, it is logical to envision the use of the SCWO process by diverse industries and public wastewater and sludge generators. This technology can be adapted to accomplish either pre or end-of-pipe wastewater treatment. There is a need to destroy both military and civilian hazardous waste, and urgency, mandated by public concern over traditional waste handling methodologies, to identify safe and efficient alternative technologies. By capitalizing on the properties of water above its critical point, 374 °C and 22.4 MPa for pure water, this technology provides rapid and complete oxidation with high destruction efficiencies at typical operating temperatures. Nevertheless, corrosion of the materials of fabrication is a serious concern. While iron-based alloys and nickel-based alloys are generally considered important for service applications, results from laboratory and pilot-scale SCWO systems presently in operation indicate that they will not withstand some aggressive feeds. Significant weight loss and localized effects, including stress corrosion cracking (SCC) and dealloying, are seen in chlorinated environments. This work assesses the corrosion characteristics of iron-based stainless steels exposed to high supercritical temperatures in a chlorinated military waste containing salts.     

高浓度难降解合成香料废水治理新技术——超临界水氧化法

超临界水氧化法在处理高浓度有机废水方面具有独特的优势,从超临界水的性质、超临界水氧化法原理、动力学、工艺和优越性等方面阐述了超临界水氧化法作为一种高浓度难降解合成香料废水治理技术具有广阔的应用前景。     

Preparation of a thick NiAl/Al2O3 coating by embedding method and its corrosion resistance under supercritical water environment

One of the critical issues in the application of supercritical water oxidation technology is to improve the corrosion resistance of reactor materials. Use of Al₂O₃ coating is one of the most promising methods to address this issue. In this study, thick NiAl/Al₂O₃ coatings on Inconel 625 substrates were prepared by a consecutive pack embedding and in-situ thermal oxidation process. The effect of aluminizing and oxidation temperature on phase structure and coating thickness is studied. Results show the diffusion of Al from the exterior to the interior of the alloy matrix to form intermetallic compounds between Al and metal elements in the matrix (Ni, Cr, Mo, etc.). Moreover, the coating thickness can reach above 300 μm at the aluminizing temperature of 950 °C. Increasing the aluminizing temperature above 950 °C will not increase the coating thickness further. After high temperature oxidation subsequently, only phases of NiAl and Al₂O₃ were detected. The formation of Al₂O₃ layer can be ascribed to the surface oxidization of Al. And the NiAl between the alloy substrate and Al₂O₃ coating provides an interfacial layer that can alleviate the crack or exfoliation of ceramic coating due to the mismatching of thermal expand coefficient. The thick NiAl/Al₂O₃ coatings prepared by aluminizing 950 °C and oxidizing at 1100 °C exhibit satisfied corrosion resistance after supercritical water test. This work would provide a significant method to develop advanced ceramics coating for the corrosion resistance of alloys.     

国外超临界水氧化技术的研究现状

超临界水氧化是水处理技术发展的新方向,但该技术对设备的要求比较高,工业化应用仍有一定的难度。为了克服这一难题,目前的研究工作主要集中在催化剂的选择以及设备防腐蚀等方面。介绍了贵金属类催化剂、过渡金属类催化剂、碱金属盐类催化剂、杂聚酸类催化剂以及碳基类催化剂,在降解不同污染物时的催化效率。在反应器材质和反应器形式的研究中,分别对铁、镊、铬等纯金属以及不同材料的合金在各种条件下的防腐蚀性能作了比较;两种最新的反应器形式:可蒸发壁式反应器和流动式反应器。它们在超临界水氧化中表现出了良好的防腐能力。     

超临界水氧化处理垃圾渗滤液的研究进展

超临界水氧化(SCWO)技术是利用超临界水表现的特殊性质而作为垃圾渗滤液处理的理想媒介。但其在应用过程中对反应器壁材料的严重腐蚀问题阻碍了其广泛的工业化应用并成为研究的热点。镍基合金作为超临界水氧化过程的耐腐材料被广泛的应用于研究中,与其他材料相比,表现出了良好的抗腐蚀性能和经济性。     

Supercritical water oxidation—Current status of full-scale commercial activity for waste destruction

After more than three decades since its potential was first recognized, supercritical water oxidation (SCWO) remains an innovative and viable treatment technology for destruction of aqueous based organic wastes. An extensive data base of destruction efficiencies, corrosion data, and salt phase behavior has been developed over the years through the combined efforts of many investigators at both the fundamental research and commercial level. As a result, SCWO technology has been increasingly utilized in a variety of full-scale designs and applications, handling feeds as diverse as polychlorinated biphenyls (PCBs), sewage sludge, spent catalysts, and chemical weapons. This paper reviews the status of current full-scale commercial SCWO facilities around the world, focusing on the unique challenges and design strategies employed by different companies for corrosion and salt precipitation control in each application. A summary of past commercial SCWO activity as well as future plans among the current active SCWO companies is also included.