高含硫天然气过滤单元性能优化

为了避免高含硫天然气湿气输送过程中所夹带的固体颗粒和液体杂质对天然气净化装置和效果的不良影响,在脱硫工艺前端设置了由预过滤器和聚结过滤器所组成的两级过滤单元。针对某高含硫天然气净化厂原料气过滤单元存在的聚结过滤器滤芯压降不上升、无法通过压降来判断滤芯更换时间等问题,利用两级过滤性能评价系统对比了不同过滤性能预过滤器滤芯和聚结过滤器滤芯组合的过滤性能,发现其原因在于聚结过滤器滤芯对亚微米级液滴的聚结性能不理想、预过滤器滤芯和聚结过滤器滤芯的性能不匹配。为此,提出了改进措施:①改进聚结过滤器滤芯的聚结层;②设置疏油型排液层,改变预过滤器滤芯的结构参数,使之与改进后的聚结过滤器滤芯的性能相匹配。实验结果表明:改进后聚结过滤器滤芯的稳态压降较在用滤芯降低75%,对于粒径为0.3μm及以上的液滴过滤效率达到99.99%,同时实现了预过滤器滤芯和聚结过滤器滤芯压降的同步变化。现场试验结果表明:改进后的原料气过滤单元对液体杂质的过滤能力提高了1倍,能更有效地保证后续工艺的安全运行。该研究成果为高含硫天然气过滤元件设计和过滤系统优化运行提供了参考。

Performance improvement of a high-sulfur natural gas filtration unit

For avoiding the adverse impacts on natural gas purification process from solid particles and liquid impurities carried by wet acid gas during its transportation, a two-stage filtration unit consisting of a pre-filter and a coalescence filter is set at the front-end of desulfurization process. In a certain acid gas purification plant, the pressure drop of the coalescence filter cartridge did not rise so that the replacement time of the filter cartridge was impossible to be diagnosed on the basis of pressure drop. In view of this, different combinations of two-stage filter cartridges were compared by using a two-stage filtration performance evaluation system. As being revealed, the problem was induced by the fact that the capture ability of coalescence filter for sub-micron droplets was not as ideal as the expectation and both filters were not matched in the filtration performance. Thus, two improvement measures were put forward: to optimize the coalescence layers of coalescence filter cartridges and to set the hydrophobic drainage layers on the coalescing filter and adjust the structure parameters of the pre-filter cartridge to match with the improved coalescence filter cartridge. Experimental results show that the steady pressure drop of the improved coalescence filter cartridge is reduced by 75%, and the filtration efficiency reaches 99.99% for the droplets with diameter ≥ 0.3 μm. Furthermore, synchronous pressure drop evolution is also realized between the pre-filter and the coalescence filter. Field tests reveal that the liquid capturing capacity is doubled by means of the improved filtration unit and the safe operation of subsequent process can be guaranteed effectively. This study provides reference for the design of natural gas filter cartridges and the optimization of natural gas filtration systems.