含硫气田水闪蒸气处理工艺评述

含硫气田水闪蒸气中含有H_2S等恶臭气体,需进行安全有效处置后才能排放,对于现有的几种处理工艺(碱液吸收、胺液吸收、液相氧化还原脱硫及干法脱硫技术)尚缺乏系统的对比分析,因而在一定程度上限制了技术的进步和推广。为此,对含硫气田水闪蒸气的来源、组成、排放特点及其控制工艺等进行了分析,探究含硫气田水闪蒸气处理的可行途径,重点从工艺原理、技术路线和适用性等方面针对当前主要的闪蒸气脱硫工艺展开评述,分析、对比了各种技术的特点和适用范围,根据潜硫量的大小对处理工艺进行了推荐,提出了技术发展的方向和建议。研究结果表明:(1)气田水闪蒸气具有含硫化氢浓度高、瞬时流量大、日均潜硫量低和压力低等特性,对其处理应满足国家标准GB/T 14554—1993中H_2S的排放要求;(2)上述几种闪蒸气处理技术各有优缺点:非再生胺液吸收工艺简单、投资较低、运行成本高、净化度低,干法脱硫工艺较简单、生产稳定、投资较高,液相氧化还原脱硫工艺适应潜硫量范围广、净化度高,但工艺复杂、投资高、稳定性较差;(3)含硫气田水闪蒸气处理应首选有组织达标排放,潜硫量在10 kg/d以内建议采用干法或胺液吸收工艺,潜硫量超过10 kg/d建议采用液相氧化还原吸收工艺。结论认为,应进一步探索气田水闪蒸气气质、气量和气速的准确变化规律,以支撑工业设计,并使装置向橇装化、标准化、模块化和自动化方向发展;同时引进增压回收和其他行业低压气体处理新技术,以完善技术体系。

Technology of flash gas treatment in sour water of sulfur-bearing gas fields

The water flash steam in sulfur-bearing gas field contains odorous gases (e.g. H2S), so it cannot be discharged until it is disposed safely and effectively. So far, however, existing flash gas treatment technologies (alkali absorption, amine liquid absorption, liquid phase oxidation-reduction desulfurization and dry desulfurization) have not been compared and analyzed systematically, so in a way, their progress and application are restricted. In this paper, the sources, components, discharge characteristics and control technology of flash gas from gas-field sour water were analyzed, and the feasible methods to treat the flash gas were explored. Currently main desulfurization processes used for flash gas were mainly described from the aspects of technical principle, technical route and adaptability. The characteristics and applicable range of various desulfurization technologies were analyzed and compared. The treatment technologies were recommended according to sulfur throughput. Finally, the development direction and suggestions on these technologies were put forward. And the following research results were obtained. First, the flash gas from gas-field sour water is characterized by high sulfur content, high instantaneous flow rate, low average sulfur throughput per day and low pressure, and its disposal shall meet the H2S emission requirements stipulated in GB/T 14554-1993. Second, each treatment technology for flash gas has its own advantages and disadvantages. The non-renewable amine liquid absorption method is technically simple with lower investment, but its operation cost is high and its purification degree is low. Dry desulfurization technology is simple and stable, but its investment is higher. The liquid phase oxidation-reduction desulfurization method is technically complex with high investment and poor stability. Third, the up-to-standard organized emission is the first choice for the disposal of flash gas from gas-field sour water. It is recommended to adopt the dry desulfurization method or the amine liquid adsorption method when the sulfur throughput is lower than 10 kg/d, and to adopt the liquid phase oxidation-reduction absorption method when the sulfur throughput is higher than 10 kg/d. In conclusion, it is necessary to further explore the exact change rules of quality, volume and velocity of flash gas from gas field water so as to support the industrial design. In addition, the devices shall be developed to be skid mounted, standard, modular and automatic. Furthermore, it is necessary to introduce the boosting recovery and the advanced lower pressure treatment technologies of other industries so as to complete the technological system.