Demulsifying compositions for destruction of water coal tar emulsions

The task of the study was to test new demulsifying compositions for high pyrolysis coal tars originally intended for separating emulsions based on heavy petroleum oils. Coal tars with a specific gravity of 1.243–1.261 were investigated and light coal tar with a specific gravity of 1.185 was used for comparison. Demulsifying compositions for heavy media were prepared on the basis of Dissolvan (Clariant) reagents, “PM” demulsifier was used as a main indicative reagent for breaking of light coal tar emulsions. To determine the efficiency of dewatering a “bottle test” was applied, Fourier transform infrared spectroscopy analysis of the distillate residues was performed to determine the functional group of potential stabilizers. The composition of the mineralized and dispersed solid stabilizers was determined by X-ray fluorescence (XRF) spectrometry. The results showed that for the heavy coal tar emulsions, some compositions based on oxalkylated resin showed high activity and separated up to 17–19% of water, in contrast to the indicative demulsifier 0–3%. An attempt has been made to investigate the mineral composition of emulsion stabilizers transferred into the water part and remaining in the coal tar (sludge). The results of XRF spectrometry suggested that Zn-pyridine compounds are the most likely hydrophile stabilizers of heavy coal tar emulsions.