Innovative approaches for metal removal from petroleum desalter effluent using biological systems

原油蒸馏装置(CDU)上游的原油脱盐脱水是脱除原油中盐分和其他有害成分的重要装置操作。该装置运行产生的海水淡化废水中含有许多污染物，如碳氢化合物乳状液、重金属、氯化物和碳酸盐等盐类、悬浮固体、硫化氢、氨和酚类化合物。目前海水淡化废水的处理方法包括沉淀法去除污泥和悬浮物、溶解气浮法去除油类和/或膜/反渗透法去除金属，但这些技术效率低且费用昂贵。海水淡化废水中重金属的存在会影响生物处理策略。迫切需要一种能在生物处理前经济地去除重金属的方法。在这项建议中，通过使用特定的生物配体，如金属结合蛋白和金属还原细菌，研究了从淡化溪流中去除重金属的方法。该项目是与帝国石油有限公司合作的。正在进行的项目中目前的研究工作包括两个步骤：(I)研究用于去除碳氢化合物和乳状液的嗜盐酵母Debarymyces hansenii，随后(Ii)使用嗜盐微藻Dunaliella Salina来去除剩余的氮和磷，并生产营养食品，如β-胡萝卜素和清洁水，供炼油厂循环使用。这些营养食品正在成为一个新的保健食品部门的有价值的材料。该项目中的工业合作伙伴帝国石油有限公司预计将更好地管理流出物，这些流出物具有很大的清洁水回收到炼油厂运营的潜力。由于利用了大量的水，炼油业的水循环利用可能是一个主要的好处。

Desalting and dewatering of crude oil upstream of the crude distillation unit (CDU) is an important unit operation for the removal of salt and other undesirable components from crude oil. The desalter effluent stream arising from this unit operation contains many contaminants such as hydrocarbon emulsions, heavy metals, salts such as chlorides and carbonates, suspended solids, hydrogen sulfide (H2S), ammonia, and phenolic compounds. Current approaches to desalter effluent treatment include sedimentation to remove sludge and suspended solids, dissolved air flotation to remove oil and/or membrane/reverse osmosis to remove metals.However these techniques are inefficient and expensive. The presence of heavy metals in the desalter effluent impacts biological treatment strategies. An approach is urgently needed which can economically remove the heavy metals before biological treatment. In this proposal, the removal of heavy metals is investigated from desalter streams by using specific biological ligands such as metal binding proteins and metal reducing bacteria. This project is in collaboration with Imperial Oil Limited. The current research efforts in the ongoing project involve a two step approach: (i) investigation of a halophilic yeast Debaryomyces hansenii for the removal of hydrocarbons and emulsions and subsequently (ii) the use of halophilic micro-algae Dunaliella salina to remove the remaining nitrogen and phosphorus and produce nutraceuticals such as beta-carotene and clean water for recycle to the refinery. These nutraceuticals are emerging as valuable materials in a new health food sector.The significant benefit envisioned for the industrial partner in this project, Imperial Oil Limited, will be better management of effluent streams with strong potential for clean water recycle into refinery operations. Water recycling in the refinery industry can be a major benefit due to the large volumes of waterutilized.