高含硫天然气净化装置闪蒸气节能工艺优化

Optimization of the flash gas treatment process for a high-H_2S natural gas purification plant

中国石化普光天然气净化厂脱硫部分采用的是Black﹠Veatch公司的专利技术,所产生的闪蒸气分两路处理,一路放空至低压火炬,一路进入尾气焚烧炉伴烧,不但造成了资源的严重浪费,而且还造成了环境污染。为此,首先对闪蒸气的组成进行分析,发现其组成与燃料气基本一致,再对其压力、水蒸气含量等进行了对比分析,进而对工艺进行了优化:将闪蒸塔直径由500mm增至800mm,当溶剂发泡时,可有效减少雾沫夹带,减少闪蒸气带液量;流量计FI-11102的节流装置管径由80mm更换为100mm,有效解决了原流量计量程不足的缺点;调节阀PV-11101B管径由40mm更换为100mm,有效增加了闪蒸气流量的调节范围;对闪蒸罐压力进行分程控制;在闪蒸气引入燃料气系统之前,先通过聚结分离器D-710,气体由分离器顶部并入燃料气系统;而分离出的液体则回收进入吸收系统,再分离出所携带的MDEA和水蒸气,避免了胺液因闪蒸气带液的损失。由此寻找出了将闪蒸气作为燃料气的应用途径,获得了明显的经济、环保效益。

The Black ＆ Veatch patented technology is adopted in the gas sweetening process of the Sinopec Puguang Natural Gas Processing Plant. The resulted flash gas in this process is usually burned as flare gas or tail gas in the end, which not only causes the waste of resources but poses risk in environmental pollution. In view of this, the components of flash gas were first analyzed and found to be quite similar to those of fuel gas, which were thus comparatively studied in terms of pressure, water vapor content, and so on. On this basis, the flash gas treatment process was optimized as follows, a. The diameter of the flash column was increased from 500 to 800 mm so the liquid-carting capacity of flash gas could be decreased by reducing the foam carrying ability when the sol- vent foamed, b. The tube diameter of the flowmeter FI 11102 was changed from 80 to 100 mm, which effectively overcame the shortcoming of limited metering range of the original flowmeter, c. The tube diameter of the control valve PV-11101B was altered from 40 to 100 mm, which increased the adjusting range of flash gas flow. d. Split control was applied concerning the pressure of the flash tank. e. Flash gas went through the coalescer and separator D710 before entering the fuel gas system from the top of the sepa- rator, e. The separated liquids were recovered back into the absorbing system, from which the MDEA and vapor were separated, thus the liquid-carting loss would be avoided. In this way, the flash gas will be employed again as a fuel gas to achieve notable eco- nomic benefit and obvious environmentally-friendly result.