羰化循环泵的机械密封设计

针对在羰基化合成醋酐工艺装置中,国产羰化循环泵在投入使用后机械密封很快失效的情况,提出对密封选材、结构设计、型式及辅助系统布置的改造方法.从经济性方面考虑结合挂片试验结果,确定采用哈氏B2作为机械密封的结构材料,全氟醚橡胶作为辅助密封材料;将机械密封设计成两级串联集装式平衡型机械密封结构,以此防止所输送的易燃、易爆、有毒高危介质（如醋酸、碘甲烷、碘化氢、丙酸等）外漏;对密封采用PLAN32＋PLAN54＋PLAN62的冲洗方案,改善密封工作环境;首级密封静环的前面设置挡环和卡簧,控制静环轴向位移;对压力较高的次级密封的各个参数进行了合理的选取和设计,保证端面的承压能力并减少摩擦生热,从而大大提高了机械密封的使用寿命和可靠性.

Design of mechanical seal used in carbonylation recycle pump

Aiming at the problem that the mechanical seal of domestic carbonylation circulation pump fails soon after putting into use in the process plant of acetic anhydride synthesis,the choice of sealing materials,transformation method for structural design,type and arrangement of auxiliary systems were proposed. Considered from economical aspect that combined the result of coupon corrosion test,Hastelloy B2 was adopted as structure material of the mechanical seal,and KALREZ as a secondary sealing material. In order to prevent the leakage of transportation medium that is flammable,explosive,toxic,highrisk（ such as acetic acid,iodine,methane,hydrogen iodide,propionic acid,etc. ） ,the mechanical seal was designed as cartridge cascaded balance type structure. PLAN 32 ＋ PLAN 54 ＋ PLAN 62 method was adopted on seal to improve the seal working condition. To control axial displacement of the first stage static ring,retaining ring and circlip were set up in front of it. The various parameters of secondary seal in higher pressure were reasonably selected and designed to ensure the pressure ability that the friction face can take and reduce the heat which was generated by friction. As a result,the service life and reliability of mechanical seal are greatly increased.