Patent ID: 8236168

Claim:
A method for producing a heavy lubricant base stock from a high alpha GTL waxy hydrocarbon wherein the base stock has a preselected haze disappearance temperature, the method comprising: isomerizing the GTL waxy hydrocarbon under isomerization conditions to form an isomerized feed; dewaxing the isomerized feed to a preselected cloud and pour point to provide a dewaxed feed; subjecting the dewaxed feed to a dehazing step including cooling and filtering to provide a dehazed feed; measuring the haze disappearance temperature of the dehazed feed and when necessary adjusting the dehazing conditions to provide a dehazed feed having the preselected haze disappearance temperature, wherein the haze disappearance temperature is measured by (a) heating a sample of the basestock to about 90° C. for about 20 minutes; (b) cooling the so heated sample to about 40° C. over about 10 minutes; (c) then further cooling the sample at a rate of about 0.5 degrees/minute to about −10° C.; (d) followed by heating the sample at a constant rate; while simultaneously (e) projecting a beam of light along an optical pathway in the sample; (f) detecting the light scattered at an 45° angle to the optical pathway by means of a photomultiplier; (g) measuring the temperature of the sample during cooling and heating; and (h) analyzing the light detected to determine the haze disappearance temperature.