Extraction of Metals from crude oil by formation of Insoluble Ionic Phases

<p dir="ltr">Trace metals are one of the components of crude oil that is a problem for the oil industry. Metals are disadvantageous in the refining, transportation, storage, and separation stages of crude oil processing. Trace metals in crude oil can lead to public health issues and endanger plant and animal life. Removing trace metals is a costly process commonly using hydrotreating and liquid-liquid extraction. These solvents are costly, difficult to prepare and not environmentally friendly. It is, therefore, necessary to look for alternative methods to simplify the extraction process. This research project focused on using deep eutectic solvents (DESs) and natural products to extract metals from crude oil. The first part of the research involves the mimicking of crude oil with copper phthalocyanine green (copper porphyrin) in toluene and investigating the thermodynamics of copper porphyrin species partitioning into the DES by using a 1:2 mixture of choline chloride and ethylene glycol (Ethaline) and Ethaline + 10% methane sulfonic acid (MSA) for the extraction. There was a good extraction of porphyrin from toluene to Ethaline but the percentage extracted increased significantly when it was acidified using methane sulfonic acid, MSA. The second part of the research studied the extraction of porphyrins from an oil analogue using natural products. Peel from three citrus fruits; orange, lemon and lime were studied along with pine bark. These were chosen as they are all common waste products which are acidic. It was shown that all of them showed good extraction efficiency for metal porphyrins. The final part of the research used crude oil obtained from Nigeria and studied the extraction of metals using DESs and natural products. All extraction media were efficient at extracting metals. In some cases, e.g., Glyceline with 10 wt.% oxalic acid, the DES develops a yellow colour from the extracted porphyrins. In other cases, e.g., BTMAC: EG acidified with MSA a separate phase formed which collected on the magnetic stirrer suggesting that the iron porphyrin was a solid magnetic phase. A separation protocol was presented which would allow the metal to be extracted and the liquid could be recycled with minimal energy for an efficient separation protocol.</p>