Patent ID: 7976640

Claim:
A method of cleaning heat exchange surfaces of a heat exchanger, wherein the heat exchanger is part of a refinery process unit, wherein the heat exchanger is being used to adjust a temperature of a process fluid flowing therethrough, wherein the process fluid comprising asphaltenic compounds, wherein at least a portion of the asphaltenic compounds have precipitated out of the process fluid onto the heat exchange surfaces, wherein the method comprising: soaking at least one of the heat exchange surfaces of the heat exchanger with an oil solvent having a Solubility Blending Number (SBN) of at least 80 to dissolve asphaltenic compounds precipitated from the process fluid in the oil solvent, wherein the oil solvent comprises at least fifty percent by volume of a crude oil with a Solubility Blending Number of at least 100 and the remainder of the oil solvent comprising a fraction, wherein the oil solvent is at a temperature of at least 25° C. when in contact with at least one of the heat exchange surfaces of the heat exchanger; removing the oil solvent with dissolved asphaltenic compounds from the heat exchanger; and processing the oil solvent with dissolved asphaltenic compounds in the refinery process unit.