NTA翻译解读.doc

CHEMICAL CLEANING NTA PROCEDURE of ACFB boilers SUZHOU 苏州 ACFB 锅炉化学清洗 NTA 程序 1 Boil out NTA 氮川三乙酸煮炉 1 1General 综述 This document includes a general description for chemical cleaning of the evaporator system by using Nitrilo tri acetic acid NTA 本文档描述 使用 氮川三乙酸 NTA 对蒸发系统进行化学清洗 Reference drawing 参考图纸 K170040 B 101 007 P I diagram 流程图 Boiler design data 锅炉设计数据 Maximum rating 最大功率 275 t h Maximum continuous rating 最大持续功率 250 t h Operation pressure 操作压力 P 125 bar a Operation temperature 操作温度 T 540 Feedwater temperature after feedwater tank T 156 给水温度 除氧器后 Feedwater temperature after hp preheater T 200 给水温度 高加后 1 2Chemistry 化学 The principle of the internal chemical cleaning is the removal of oxide layers scale and other deposits in order to create a metallic clean surface upon which a homogeneous magnetite layer can be formed 内部化学 清洗是为去除氧化层 剥落层和其他沉积物 达到一个金属清洁表面 这就可以形成一层均匀的磁铁矿层 On the other hand it is necessary to get the required steam quality for turbine operation as fast as possible 另一个方面 有必要尽可能快地获 得汽机操作所需的蒸汽质量 Nitrilo tri acetic acid NTA is an organic chelating agent and removes deposits containing iron oxides Fe304 under alkaline NH3 and reducing N2H4 conditions at temperatures between 160 220 氮川三 乙酸 NTA 是一种有机络合剂并能除去碱性 NH3 下的含铁氧化物 Fe304 的沉积物以及在条件温度 160 220 之间还原 N2H4 Temperatures 220 effecting a partly decomposition of the chelating chemical 温度 220 影响螯合化学物质的部分分解 HOOC CH2 N CH2 COONH4 HOOC CH2 Alkaline conditions are to be achieved by using the mono ammonium salt of NTA the reaction with pure iron surface is very low 使用 NTA 的单 铵盐达到碱性条件 用纯铁表面上的反应是非常低的 Reducing conditions will be achieved by using of hydrazine N2H4 还 原条件将通过使用肼来实现 N 2 H 4 Fe3O4 FeOFe2O3 1 2N2H4 3FeO 1 2N2 H2O Nh4nta reacts with fe2 ions of the oxide and forming a stable 1 1 complex with NTA Nh4nta 与 Fe2 的氧化物离子反应形成稳定的 1 1 NTA 复合物 FeO NTANH4 NTAFe NH4OH 1g NTA removes 0 4g Fe3O4 1 2 1 Advantage of NTA cleaning NTA 清洗的优点 High cleaning efficiency by minimizing corrosion risks metal loss 40 g m2 高清洗效率最大限度地减少腐蚀的风险 金属损失 9 0 对于所有的冲洗步骤 除盐水应与氨 肼 进行调节 以使 pH 值 9 0 1 4 3 NTA cleaning NTA 清洗 1 4 3 1Filling of chemicals 化学物质填充 1 The concentrated cleaning solution NTA content 10 have to be prepared in a separate tank see also point1 4 3 2 将浓缩清洗溶液 NTA 含量 10 应该用一个单独的罐来制备 参见 1 4 3 2 2 The boiler will be filled by means of one feedwater pump 5 to 10 minutes 锅炉将使用一个给水泵填充 5 至 10 分钟 3 Stop the feedwater pump 停止给水泵 4 Pump the cleaning solution into the drain of the economizer to the boiler 用泵将清洗液抽入省煤器排水管到锅炉 5 Start the feedwater pump 开启给水泵 6 Fill the drum with feedwater to 150mm drum level 汽包给水进水 到汽包水位 150mm Conductivity PH value will be checked on the sampling station 电导率 pH 值将在取样站进行检查 1 4 3 2Required chemical and concentration 所需的化学和浓度 Required amount and concentration of chemicals 所需量和化学品浓度 Volume evaporator system 容量 蒸发系统 1m3 68m3 NTA 5kg m3 340kg Hydrazine N2H4 100 联氨 0 6kg m3 41kg Ammonia NH3 100 氨 1 0kg m3 68kg PH value of chemical solution 化学溶液的 ph 值 8 5 9 1 4 3 3Circulation and heating up 循环和加热 1 After completion the preparation works including filling of water and chemicals the boiler must be prepared for a start up according operation manual 完成后的准备工作 包括加注水和添加化学品 必须准备启动锅炉 根据操作手册 2 Further checks of pH value and conductivity must be carried out 必须 进一步检查 pH 值和电导率 3 When the results of analysis indicates a homogeneous solution the cycle will be heated up by starting one oil burner 当分析结果为均匀 的溶液时 通过启动油燃烧器将该循环加热 4 When the temperature in evaporator system reaches 180 the drum level shall be kept at approx 100mm 当蒸发器系统中的温度达到 180 汽包水位应保持在约 100 毫米 5 When the temperature in evaporator system reaches 200 approx 16 bar drum pressure the burner must be kept at this temperature for 3 hours 当在蒸发器系统的温度达到 200 约 16bar 巴汽包压力 燃烧器必须在该温度下保持 3 小时 6 The natural circulation will start automatically when the temperature is increasing 当温度越来越高 自然循环将自动开始 7 The cleaning time will be 3 hours counted from the time when the temperature has reached 200 清洗时间为 3 小时 当温度达到 200 开始计时 8 If the cleaning time is finished exchange the NTA water via drum overflow valve fill up the lost water with feedwater operating drum level 0mm for 2 hours and continue with the drying curve 如果清洗 时间结束后 通过汽包溢流阀更换 NTA 水 填补丢失的水分与 给水 操作汽包水位 0 毫米 2 小时 并继续进行干燥曲线 9 Boil out finished 煮炉结束 1 4 3 4Process monitoring 过程监控 acid concentration via conductivity 酸浓度 通过电导率 iron content 铁含量 pH value pH 值 Samples has to be taken all 15 30 minutes from the on when the temperature in the system has reached approx 160 If the iron concentration in the cleaning solution is constant indicates that all oxides have been already dissolved the cleaning process is finished 当系统温度达到大约 160 取样时间为 15 30 分钟 A soak phase of approximately 1 hour allows the formation of thin homogeneous magnetite layer which makes no further passivation steps necessary 约 1 小时浸泡阶段允许有均匀的薄磁铁矿层形成 这使得 没有必要进一步钝化 1 4 3 5Draining of the system 排水系统 If the cleaning time is finished drain the NTA water via drum overflow valve see point 4 3 3 如果清洗时间到了 通过汽包溢流阀完成 NTA 排水 见 4 3 3 1 4 3 6Flushing after refractory drying NTA cleaning 耐火材料干 燥后冲洗 NTA 清洗 1 4 3 7For displacement of the residual cleaning solution flushing with treated demineralisated water must be done 必须使用处理过 的除盐水冲洗剩余的清洗液 1 4 4 Water volume of evaporator system 蒸发系统水量 Evaporator system 蒸发系统 System description 系统描述Volume m3 Evaporator connection lines and downcomers 蒸发器 连接管及下降管 51 Drum Eco 汽包 省煤器17 Entire Volume 总量68 1 4 5 Disposal of cleaning solution 清洗液处理 Disposal suggestion 处理建议 NTA is biodegradable by 95 95 NTA 可生物降解的 The cleaning solution contains Ammonia NH3 and should be coll