Patent ID: 8609429

Claim:
A method for determining temperature sensitivity related to propensity of a hydrocarbon stream to foul process equipment, comprising: a. introducing a hydrocarbon stream to a test unit, the test unit comprising a chamber defined by a wall for the hydrocarbon to flow through, an inlet for feeding the hydrocarbon into the chamber, an outlet to discharge the hydrocarbon stream, and a heating element maintained at a substantially constant surface temperature Tc and disposed within the chamber to heat the hydrocarbon flowing across the surface of the heating element to cause fouling; b. obtaining a series of temperature measurements over time of the hydrocarbon stream exiting the outlet of the test unit, including: 1) measuring an initial temperature T 1 of the hydrocarbon exiting from the outlet when the heating element is essentially free from fouling; 2) measuring the temperature T(t) of the hydrocarbon exiting from the outlet successively at predetermined time intervals subsequent to measuring the initial temperature T 1 , where t denotes time; c. determining a parameter value indicative of a propensity of the hydrocarbon to foul process equipment by a regression of ΔT(t) according to the following expression: Δ ⁢ ⁢ T ⁡ ( t ) = 1 - [ 1 + σ ⁡ ( ut / L - 1 ) ( 1 - σ ) ⁢ ( 1 + σ ⁢ ⁢ ut / L ) ] 1 / ( σ ⁢ ⁢ P ) where ΔT(t) is a time-dependent quantity which is defined as ΔT(t)=[T(t)−T 1 ]/(T c −T 1 ), σ is the fouling parameter value at surface temperature of the heated element Tc, t is time, u is the average velocity of the hydrocarbon in the chamber of the test unit, L is the length of the section of the chamber, and P is a factor relating to heat transfer; d. repeating steps (a)-(c) at a second and different surface temperature of the heating element to obtain a fouling parameter value at the second temperature of the surface of the heated element; and e. determining the activation energy Ea of the fouling by the hydrocarbon stream based on the Arrhenius principle using the determined fouling parameters obtained at the first and second temperatures.