销酸用铂网在使用中遇到的问题及改进建议.pptVIP

Nitro Technologies 硝酸用铂网在使用中遇到的问题及改进建议 全国第八届硝酸硝酸盐技术交流研讨会 上海贺利氏工业技术材料有限公司 2013年11月27日 湖南 长沙  1.中国硝酸情况概述 中国硝酸工业在最近10年经历了快速发展期 据统计，截至2015年将达到近2100万吨 关键设备和部件均实现国产化 铂网作为生产硝酸用的关键催化剂，在使用中遇到了不少的问题和故障 2.双加压硝酸原料过滤系统 3.1铂网在使用过程中遇到的问题 硝酸铂网表面被粉尘严重覆盖 3.2由于特定气体和杂质导致的不能点火 铂-硫的二元合金相图 铂丝被氯腐蚀的电镜照片 3.3由于特定气体和杂质导致的不能点火 3.4 由于被油污污染导致的铂网中毒 空气和氨中都有可能含有润滑油成分 以一套500吨/天的硝酸装置举例，氨中的油含量限值2mg/Nm3 每天需要的氨为190000Nm3（142t） 则180天周期内，将有68.4Kg的油被带到铂网的表面。 润滑油的雾滴在遇铂网时可被燃烧并分解为含碳、硫、氯的物质。 3.5 由于含铁的物质混入导致效率下降 表面被铁锈污染的铂网 3.6 由于含铁的物质混入导致效率下降 原料尤其是氨中的铁催化剂对铂网的毒性最强 快速、大幅降低铂网的活性 N2O排放水平飙升 铂网微观结构改变，无法恢复活性 4. 改进的建议和意见 改造原料净化系统 避免吸入有毒气体 彻底清除铁锈和铁杂质 谢谢! * * All catalyst gauzes used in the ammonia oxidation consist of platinum rhodium alloys. It is generally accepted that platinum is the main catalytic component. So, what is rhodium good for? The presentation discusses this issue. * * The catalytic ammonia oxidation is often called the Ostwald process. This is because it was Ostwald, a chemistry professor in Leipzig, who developed the process of catalytic ammonia oxidation on industrial scale at the beginning of the twentieth century. Ostwald used thin, corrugated platinum ribbons formed into a spiral as the catalyst. The process has gained on importance after Haber and Bosh made ammonia easily available on industrial scale in 1911. The next step in the development of catalyst was the replacement of platinum ribbons by gauzes which was introduced by Kaiser. Eventually, in 1929 Davis of Du Pont proposed to add rhodium to platinum. This turned out to be so successful that until today all alloys for catalytic ammonia oxidation contain rhodium. * * The adition of rhodium to platinum was dictated by the fact that due to a fairly low mechanical strength of platinum, it was difficult to manufacture thin wires for gauzes. By adding rhodium, the strength of platinum is significantly increased. The diagram shows a comparison of tensile strength of platinum an alloys most commonly used in catalyst gauzes: