Which domestic manufacturer produces the highest-quality economizers?
Thread Content
In the new sulfuric acid production system installed by our company, the economizer started leaking within less than 2 months of operation. The sulfuric acid generated by the water and flue gas corroded and punctured the shell of the economizer; even the 15mm thick steel plates that were welded in place developed holes within 6 hours. The main reasons identified are as follows: 1\ During the trial production phase, the fans were not properly adjusted, resulting in short-term overpressure – about 1 KPa above the design pressure. 2\ There were defects in the welding of the heat exchange tubes in the economizer, and these minor leaks led to widespread corrosion of the shell by the acidic liquid. Please share any information on this topic!! Thank you
Xiao Wenchao: 025-83202045, 025-83202046, 025-83202047, 13705150327. Jiangsu Kesheng Thermal Energy Equipment Engineering Co., Ltd. Manager: Senior Engineer Wang Hong. Products: Economizers (boilers). Contact numbers: 025-83202045, 025-83202046, 025-83202047; Phone number: 13605173066. Address of Jiangsu Kesheng Thermal Energy Equipment Engineering Co., Ltd.: No. 83, Yunnan North Road, Nanjing. Cheng Shaoyi: Phone number: 13808703810. Hailu Kunlun. Marketing Manager and Director of the Chengdu Office: Senior Engineer Zhao Xiaohui. Contact numbers: 021-55560020, 028-85051687, 021-65082138, 028-85051687. Phone numbers: 13908095087 (Shang), 13908095087 (Sichuan). Address of Hailu Kunlun: 7th floor, Deyang Huayuan Office Building, No. 267, Quyang Road, Shanghai. Assistant Chief Engineer Chen Qi. Contact numbers: 021-55560020-511, 021-65082138, 021-65082941. Phone numbers: 13601746332, 13311867165. Address of Hailu Kunlun: 7th floor, Deyang Huayuan Office Building, No. 267, Quyang Road, Shanghai； No. 7, West Section 1 of First Ring Road, Chengdu. Project manager: Wu Dengyong. Contact numbers: 025-83113911, 025-83113977, 025-83113922, 13675162225. Address of Nanjing Jianuo Energy Equipment Co., Ltd.: No. 276-1, Central Road, Nanjing. Person in charge: Du Liangyun. Contact numbers: 0871-6618297, 13529286160. Kunming office of Shanghai Hailu Kunlun High-Tech Engineering Co., Ltd. According to investigations, Jiangsu Kesheng is quite good; many manufacturers choose its products, and we too opt for Kesheng’s products ；
Our company uses heat pipe economizers from Shanghai, and they haven’t leaked in 10 years.
In fact, most manufacturers encounter such problems, and there isn’t a very good solution. 1. The direct control method is to increase the temperature of the flue gas. 2. Control the moisture content at the outlet of the drying tower. 3. Monitor process parameters in a timely manner, observe the exhaust gas conditions, and determine whether there is a leak in the water vapor system. 4. It is best to operate at full capacity to improve the efficiency of the demister.
Due to the low metal wall temperature at the water inlet of the economizer, dew point corrosion may occur. When the wall temperature of the economizer’s metal is lower than the dew point temperature, acid mist will condense on the outer wall of the tubes, forming condensed acid. Of course, corrosion does not necessarily occur once condensed acid is formed; it also depends on the concentration and temperature of that condensed acid. Under normal operation, if dew formation occurs, fuming sulfuric acid (concentration >102%) is generally generated; at temperatures below 120°C, carbon steel can also resist corrosion in such conditions. During startup and shutdown, as well as in the event of leaks from the thermal equipment mentioned earlier, the dew point temperature rises. The temperature of the condensate acid formed by dew formation also increases, and the concentration range of sulfuric acid produced by dew formation is wide; under such conditions, only cast iron can resist corrosion. There are currently two approaches in our country. The first approach involves using heat pipe economizers; through heat pipe technology, the temperature of the metal walls in contact with the furnace gases is kept above the dew point temperature during normal operation, thereby preventing condensation and dew point corrosion. On the other hand, even if dew point corrosion occurs during startup/shutdown or when there is a leak in the heat recovery equipment ahead, the water inside the heat pipe economizer will not leak into the furnace gas; therefore, this method is a safe and reliable approach with Chinese characteristics. Ordinary carbon steel economizers can be used when the heat recovery equipment is safe and reliable, as corrosion generally does not occur even in the presence of dew during normal operation, and the dew point corrosion that occurs during startup and shutdown has little impact on the overall corrosion process. Furthermore, whether a heat pipe economizer or a conventional carbon steel economizer is used, it is preferable that the tubes in the heat-exchanging surface in contact with the furnace gas have no butt welds.