摘要
网状阳极系统的优点在于储罐外底板保护电位分布均匀,对附近管道干扰小。采用瞬时同步断电法对2个站场的11座储罐进行检测,结果表明:控制电位达到-1.1V时,储罐仍可能未达到有效保护,原因是恒电位仪输出电流或保护电流密度过小,而日常管理通常只关注通电电位,易忽视因IR降造成的欠保护。储罐阴极保护相关标准要求电流密度在1～10mA/m2,推荐范围为5～10mA/m2,而检测结果表明:两站场电流密度为1～2mA/m2时,断电电位基本达到了-850mV。由于电流密度需求受储罐液位和季节等其他因素影响,虽然标准中仅要求在阴极保护系统投运时以消除IR降电位确认电流密度需求,但在运行维护过程中仍需定期以断电电位确认电流密度需求,以有效避免潜在的欠保护风险。(表12,参5)
The advantage of the grid anode system is that the protection potential is evenly distributed on the storage tank＇s bottom plate, with small interference on nearby pipeline. The test results from 11 storage tanks in two pump stations with instantaneous synchronized switch-off method showed that when control potential reached -- 1.1 V, the tank still may not be effectively protected because the potentiostat output current or protection current density was too small, however, the daily management were usually only concerned with energized potential, easily overlooking under-protection due to the IR drop. The standards on storage tank cathodic protection require that the current density should be 1-10 mA/m2, and the recommended range is 5~10 mA/m2, but test results showed that when the current density of two pump stations was 1-2 mA/m2, the switch off potential reached --850 mV. As the current density requirements are influenced by tank level and seasonal factors, although the standards only require that current density requirement is determined based on potential eliminating IR drop when cathodic protection system is put into operation, it is still required to regularly determine the current density requirements in operation and maintenance process based on switch off potential to effectively avoid the risk of under-protection. （12 Tables, 5 References）
出处
《油气储运》
CAS
2013年第4期426-430,共5页
Oil & Gas Storage and Transportation
关键词
站场
储罐
网状阳极
阴极保护
电流密度
断电电位
stations, storage tank, grid anode, cathodic protection, current density, switch offpotential
