SCORE丙烷回收流程模拟与分析

Simulation and analysis of SCORE propane recovery process

关键词:  SCORE  丙烷回收  流程特性  适应性 

Key words:  SCORE  propane recovery  process characteristic  adaptability

摘要:

单塔塔顶循环(SCORE)工艺是国外广泛采用的一种低温分离流程,主要用于回收天然气中丙烷及比丙烷更重组分,是在塔顶循环(OHR)丙烷回收流程基础上的一种改进丙烷回收工艺,该工艺流程具有流程简单、丙烷回收率高、系统热集成度高、对气质适应性强等特点。分析了SCORE工艺流程结构、工艺原理及流程特征,流程中脱乙烷塔采用复合塔,由吸收段与分馏段组合而成,侧线气相抽出物流经冷凝分别为吸收段提供回流和侧线气相抽出补充物料,低温侧线液相抽出物流预冷原料气可降低重沸器负荷,提高系统热集成度和丙烷回收率。重点通过实例分析塔顶回流、气相及液相抽出物流等操作条件对SCORE流程的丙烷回收率及系统能耗的影响。并选取3组不同气质对SCORE流程进行适应性分析,结果表明,SCORE流程是一种回收率高、适应性较宽的高效丙烷回收流程,值得在我国丙烷回收工程领域推广应用。 

Abstract:

SCORE (Single Column Overhead Recycle) process is a cryogenic-separation process which is widely used abroad and mainly for recovery of propane and heavier compositions in natural gas. SCORE process is improved from OHR (Overhead Recycle) process, and it has characteristics of simple flow, high propane recovery, well integrated system, strong adaptability for natural gas with different richness. The SCORE process structure, principles and characteristics are analyzed in this article. Composite column consisting of absorbing section and stripping section has been adopted in SCORE process. A with-drawn gas flow is cooled and its condensate for reflux of absorbing section and feed of with-drawn gas flow. The feed gas is cooled by cryogenic with-drawn liquid flow which results in lower reboiler energy consumption, better integration of system and higher propane recovery. Effects of operating conditions such as column overhead reflux, with-drawn gas and liquid flow on SCORE process propane recovery and system energy consumption are analyzed in this article by actual cases. Three sets of natural gases with different richness are selected to study SCORE process adaptability, and the results show that SCORE process is an efficient recovery process with high propane recovery and wide range of adaptability. And it is worthy of promotion in propane recovery engineering field in our country.