延长硫磺回收装置蒸汽过热器使用寿命的探讨

Study on measures to increase the operating life of steam superheater in sulfur recovery unit

中国石油化工股份有限公司洛阳分公司硫磺回收装置采用中压蒸汽过热器回收尾气焚烧炉内产生的高温烟气热能,降低装置运行成本.受原料酸性气流量波动影响,有时出现蒸汽过热器炉管超温甚至爆管现象.针对蒸汽过热器炉管超温的现象,从工艺操作、设备腐蚀等方面进行了分析,并提出了预防和改进措施：装置较低负荷运行时,过热蒸汽压力在大于3.5 MPa,1.0～3.5 MPa和小于1.0 MPa时,采取依次并入3.5 MPa,1.0 MPa和0.3 MPa蒸汽管网等操作;适时监控酸性气燃烧炉废热锅炉水质,使其pH值控制在8.0～9.5,磷酸根质量浓度控制在10～50 mg/L;尾气焚烧炉配风比控制在3左右.装置连续稳定运行10个月,有效延长了设备使用寿命.

The middle-pressure steam superheater is applied in the sulfur recovery plants of SINOPEC Luoyang Company to recover the thermal energy from the high-temperature flue gas from tail gas incinerator, and the running cost has been saved. Due to the impact of the feed fluctuation, the steam superheater overhea- ting and tube rupture occurred occasionally. The causes are analyzed in respect of process, operation and equipment corrosion, and effective prevention and improvement measures are proposed such as： the overhea- ting steam goes to the 3.5 MPa steam network, 1.0 MPa steam network and 0.3 MPa steam network, when the steam pressure is 〉 3.5 MPa, 1.0 ~ 3.5 MPa and 〈 1.0 MPa respectively under the underload condition. The water quality of the waste heat boiler for sour gas burner should be properly controlled in time, the pH val- ue should be maintained at 8.0 - 9.5 and the concentration of the phosphate radical should be maintained at 10 - 50 mg/L. The ratio of gas to air should be controlled at about 3 in the tail gas burner. After implementa- tion of above preventive measures, the plants have run 10 months steadily and smoothly, and the service life of the steam superheater has been greatly extended.