Ethane recovery from residue gas by adsorption processes: A feasibility study

NOVA化学公司（NCC）是加拿大最大的乙烯生产商之一。乙烯是聚乙烯的基本原料，是全球生产中最重要的石化产品之一。乙烯是由乙烷生产的，乙烷是通过气体过冷工艺（GSP）从天然气中提取的。在这个过程中，天然气被冷却，并使用低温分离成两个部分。称为残余气体的较轻馏分含有96-98摩尔%甲烷和1-3摩尔%乙烷。残余气体被压缩并输送到管道，在管道中，未回收的乙烷作为燃料与甲烷一起沿着，而不是转化为增值产品。由于现有工艺的局限性，将高价值乙烷的回收率提高到80%以上是不经济的。如果采收率提高到95%，加拿大的产量每天可增加5万桶。NCC正在研究替代分离工艺，以提高乙烷回收率。目前的参与加建议是一个正在进行的参与项目与阿尔伯塔大学（UofA）的延续。Engage项目表明，吸附（一种利用某些固体从气体混合物中选择性保留一种成分的能力的分离技术）可以生产高纯度乙烷，并有可能被纳入生产过程。虽然Engage赠款侧重于独立的吸附工艺，但目前的Engage plus提案将探索将该工艺整合到NCC运营的现有天然气开采厂中的方法。它将专门研究对能源消耗的影响，并为NCC提供数据，以估计这种整合的成本。该项目的成功可能会导致避免事故。每天有5万桶乙烷作为燃料燃烧，并将其作为乙烯制造商的原料。NCC是加拿大生产的大多数乙烷的主要消费者，将能够说服NGL提取厂运营商考虑这项技术。

NOVA Chemicals Corporation (NCC) is one of the largest producers of ethylene in Canada. Ethylene is the building block for polyethylene and is one of the most important petrochemicals in terms of global production. Ethylene is produced from ethane which is extracted from natural gas through the gas sub-cooled process (GSP). In this process, natural gas is cooled and separated into two fractions using a cryogenic. The lighter fraction which is termed as the residue gas, contains 96-98 mol% methane and 1-3 mol% ethane. The residue gas is compressed and sent to the pipeline where the unrecovered ethane is burnt as a fuel along with methane, instead of being converted to value added products. Owing to the limitations of the current process, it becomes uneconomical to increase the recovery of the high-value ethane beyond 80%. An additional 50 thousand barrels per day could be added to the Canadian production if the recovery is improved to 95%. NCC is studying alternate separation processes to improve ethane recovery. The current Engage plus proposal is a continuation of an ongoing Engage project with the University of Alberta (UofA). The Engage project showed that adsorption (a separation technology that exploits the ability of certain solids to selectively retain one component from a gas mixture) can produce high purity ethane and has the potential to be incorporated into the production process. While the Engage grant focused on a stand-alone adsorption process, the current Engage plus proposal will explore the methods to integrate the process into the existing natural gas extraction plant operated by NCC. It will specifically study the impact on energy consumption and provide data for NCC to estimate the cost of such an integration. Success of the project could result in avoiding ca. 50 thousand barrels per day of ethane being burnt as a fuel and diverting them as feedstocks for the ethylene manufacturers. NCC being the primary consumer of most ethane produced in Canada will be in a position to convince NGL-extraction plant operators to consider this technology.