Molecular Design of Novel Chemicals for Iron Sulfide Scale Removal

Abstract

Scale deposition is a pertinent challenge in the oil and gas industry. Scales formed from iron sulfide are one of the troublous scales, particularly pyrite. Moreover, the use of biodegradable environmentally friendly chemicals reduces the cost compared to the conventional removal process. In this work, the chelating abilities of four novel chemicals, designed using the in silico technique of density functional theory (DFT), are studied as potential iron sulfide scale removers. Only one of the chemicals containing a hydroxamate functional group had a good chelating ability with Fe2+. The chelating strength and ecotoxicological properties of this chemical were compared to diethylenetriaminepentaacetic acid (DTPA), an already established iron sulfide scale remover. The new promising chemical surpassed DTPA in being a safer chemical and having a greater binding affinity to Fe2+ upon optimization, hence, a better choice. The presence of oxime (-NHOH) and carbonyl (C=O) moieties in the new chemical showed that the bidentate form of chelation is favored. Moreover, the presence of an intramolecular hydrogen bond enhanced its chelating ability.

Unblocking Process of Complex Sulfur–Iron Scale Blockage in Sulfur-Bearing Gas Wells and Its Mechanism

“…Chelating agents are used as alternatives to conventional acids to dissolve sulfur and iron scales. In comparison, chelating agents have the advantages of environmental friendliness, low corrosion rate, good solvency power and low sludge tendency. , Chelating agents are organic compounds that can form multiple coordination bonds and form heterocycles through electron donor, and various carboxylic acids are the most common chelating agents used in oil and gas applications. , The role of chelating agent is mainly divided into two parts, one is the chelating agent directly on the surface of the scale sample, making the iron–sulfur bond unstable and thus soluble; the other is the chelation of the free iron hydrolyzed from the scale sample and thus soluble. ,, …”

“…6,7 The role of chelating agent is mainly divided into two parts, one is the chelating agent directly on the surface of the scale sample, making the iron− sulfur bond unstable and thus soluble; the other is the chelation of the free iron hydrolyzed from the scale sample and thus soluble. 3,4,11 Therefore, this paper starts from the composition of sulfur and iron scale in the high abrasive edge with a lamp shadow group, determines the composition of the scale sample by FT-IR, SEM, EDS and XRD, and combines the molecular structure characteristics of the scale sample and the chelating agent to select the chelating agent that can chelate efficiently. Then we proposed the combination process of "dispersionchelation-dissolution", and finally constructed an environmentally friendly and efficient technology and formula for descaling sulfur and iron scales, and studied its descaling mechanism.…”

“… 6 , 7 The role of chelating agent is mainly divided into two parts, one is the chelating agent directly on the surface of the scale sample, making the iron–sulfur bond unstable and thus soluble; the other is the chelation of the free iron hydrolyzed from the scale sample and thus soluble. 3 , 4 , 11 …”

Assessing the Versatility of Bioextraction to Preserve Waterlogged Wood

“…For instance, molecules with similar structures of EDTA have been synthesized and present potential for an alternative eco-friendly iron complexation [26]. Some laboratories also suggested to encapsulate the harmful iron sulfides within the wood instead of extracting them as they are part of the objects' history [27].…”

Geometrical and Electronic Analysis of Polyepoxysuccinic Acid (PESA) for Iron Sulfide Scale Inhibition in Oil Wells

“…[2]. However, one of the troublesome scales in oil and gas wells is the formation of iron sulfide [3]. The combination of iron and hydrogen sulfide in sour oil and gas production wells causes the iron sulfide scale to develop.…”