炼油技术与工程 ›› 2022, Vol. 52 ›› Issue (9): 32-36.

• 加工工艺 • 上一篇    下一篇

丙烷脱氢装置液相进料脱水问题分析与探讨

刘晓成1,郭海艳2,陈义丰1,陈尊仲1,张波杰1,万亿青1   

  1. 1.宁波金发新材料有限公司; 2.中国石油化工股份有限公司镇海炼化分公司
  • 收稿日期:2022-03-25 出版日期:2022-09-15 发布日期:2022-09-20
  • 作者简介:刘晓成，工程师，注册安全工程师，硕士，毕业于常州大学有机化学专业，从事丙烷脱氢装置工艺和安全管理工作。E-mail:lxc754131aa@163.com。

Analysis and discussion on dehydration of liquid-phase feed in PDH unit

Liu Xiaocheng1,Guo Haiyan2,Chen Yifeng1,Chen Zunzhong1,Zhang Bojie1,Wan Yiqing1   

  1. 1.Ningbo Kingfa Advanced Materials Co., Ltd.; 2.SINOPEC Zhenhai Refining & Chemical Company
  • Received:2022-03-25 Online:2022-09-15 Published:2022-09-20

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摘要：

丙烷脱氢装置液相进料干燥器压差和干燥器出口水含量超设计值是由干燥器床层下部分子筛粉化和板结所致，液相进料带水的根本原因是上游设备分水效果不佳。在3A分子筛质量合格的前提下，分析水、硫化氢、再生程序和分子筛装填方案对3A分子筛粉化、板结的影响，从3A分子筛装填方案和日常操作两个方面采取优化措施。3A分子筛装填方案优化措施：在干燥器床层底部增加吸水硅胶床，减少水对分子筛的影响；分子筛床层顶部预留活动空间，减少至50 mm。3A分子筛日常操作优化措施：在分子筛再生程序中分子筛的吹扫时间延长1 h;再生时升降温速率由原来的50℃/h降至30℃/h;在分子筛再生程序中延长排液时间，在排液程序完成后再次手动排液，确保干燥器中的液相进料全部排空；工艺上控制硫化氢含量，减少对分子筛的影响。实践证明：分子筛短时进水后，在分子筛再生程序中延长5 h的干燥时间，并同步将分子筛再生温度提高10℃,经过3个再生周期后，3A分子筛吸附性能恢复正常。

关键词: 丙烷脱氢, 液相进料脱水, 3A分子筛, 粉化, 板结, 再生程序, 装填方案

Abstract:

The pressure difference of the liquid-phase feed dryer of the propane dehydrogenation(PDH) unit and the water content of the dryer outlet exceeded the design values because of the pulverization and compaction of the molecular sieve in the lower part of the dryer bed. The fundamental reason for the liquid-phase feed with water was the poor separation effect of the upstream equipment. The effects of water, hydrogen sulfide, regeneration program and molecular sieve packing scheme on the pulverization and compaction of 3 A molecular sieve were analyzed under the premise of its own qualified quality. Optimization measures were taken from two aspects of 3 A molecular sieve packing schemes and daily operations. Optimization measures for 3 A molecular sieve packing schemes were as follows: adding a water-absorbing silica gel bed at the bottom of the dryer bed to reduce the influence of water on the molecular sieve; reducing the reserved active space at the top of the molecular sieve bed to 50 mm. Optimization measures for the daily operations of 3 A molecular sieve were as follows: extending the purging time of molecular sieve by one hour in the molecular sieve regeneration program; reducing the heating and cooling rate from 50 ℃/h to 30 ℃/h during regeneration; extending the draining time in the molecular sieve regeneration program, and manually draining the liquid again after the completion of the draining program to ensure that the liquid-phase feed in the dryer was completely drained; controlling the hydrogen sulfide content to reduce the impact on molecular sieves in the process. The results indicated that after the molecular sieve was fed with water for a short time, the drying time was extended by 5 hours in the molecular sieve regeneration program, and the regeneration temperature of the molecular sieve was simultaneously increased by 10 ℃. After 3 regeneration cycles, the adsorption performance of 3 A molecular sieve returned to normal.

Key words: PDH, dehydration of liquid-phase feed, 3A molecular sieve, pulverization, compaction, regeneration program, packing scheme