Sulfur-treated propane-precipitated asphalt
AssigneeExxon Research & Engineering Co.
InventorsDominick Clementoni, Luke W. Corbett
Life of this patent
Estimating the term…
Abstract
Propane-precipitated asphalt is heated with 1-15 wt. % elemental sulfur at 140.degree. to 300.degree. C. until hydrogen sulfide evolution ceases. The sulfur-treated asphalt base material having an increased softening point of about 65.degree.-300.degree. C., is blended with 5-60 wt. % liquid petroleum fraction, such as vacuum gas oil or extract oil, having an equivalent atmospheric boiling point of 370.degree.-500.degree. C., to yield a quality paving grade asphalt cement composition meeting ASTM standards.
Claims17
A process for preparing an asphalt cement composition comprising the steps of:
- (a) heating a mixture consisting essentially of a propane-precipitated asphalt, derived from a residuum of a crude oil, having a gravity of above about 20.degree. API, and 0-60 weight percent, based on the total weight of said asphalt, of a liquid petroleum fraction, having an atmospheric equivalent boiling range of about 370.degree.-500.degree. C., and about 1 to 15 wt.% elemental sulfur, based on the total weight of said asphalt, at a temperature in the range of about 140.degree. to 300.degree. C., until hydrogen sulfide evolution ceases, thereby resulting in a sulfur-treated asphalt base having an increased softening point, compared to that of said propane-precipitated asphalt, and being in the temperature range of about 65.degree.-300.degree. C. as measured by ASTM D 36-76;
- and
- (b) blending said sulfur-treated asphalt base with about 0-60 weight percent, based on the total weight of said asphalt base, of said liquid petroleum fraction, such that the total amount of said petroleum fraction present is about 5-60 weight percent of said asphalt base, thereby producing an asphalt cement composition, being of ASTM viscosity grade AC-21/2, AC-5, AC-10, AC-20 or AC-40 and meeting the requirements of ASTM D 3381-76 or AASHTO M 226-73, and exhibiting a higher viscosity at 60.degree. C. (ASTM D 2171-66), as measured by the procedure of ASTM STP 532 (1973), in which said viscosity is interpolated at a penetration level of 90 decimillimeters at 25.degree. C., than a comparative non-sulfur treated composition, derived from the same propane-precipitated asphalt whose softening point has not been increased.
A process for preparing an asphalt cement composition comprising the steps of:
- (a) heating a mixture consisting essentially of a propane-precipitated asphalt derived from a residuum of a crude oil, having a gravity of about 30.degree.-40.degree. API, and about 1 to 15 wt.% elemental sulfur, based on the total weight of said asphalt, at a temperature in the range of about 140.degree. of said asphalt, at a temperature in the range of about 140.degree. to 300.degree. C., until hydrogen sulfide evolution ceases, thereby resulting in a sulfur-treated asphalt base having an increased softening point, compared to that of said propane-precipitated asphalt, and being in the temperature range of about 65.degree.-300.degree. C. as measured by ASTM D 36-76;
- and
- (b) blending said sulfur-treated asphalt base with about 5-60 weight percent, based on the total weight of said asphalt base, of a liquid petroleum fraction, having an atmospheric equivalent boiling range of about 395.degree.-475.degree. C., thereby producing an asphalt cement composition being of ASTM viscosity grade AC-21/2, AC-5, AC-10, AC-20 or AC-40 and meeting the requirements of ASTM D 3381-76 and AASHTO M 226-73, and exhibiting a higher viscosity at 60.degree. C. (ASTM D 2171-66) as measured by the procedure of ASTM STP 532 (1973), in which said viscosity is interpolated at a penetration level of 90 decimillimeters at 25.degree. C., than a comparative non-sulfur treated composition, derived from the same propane-precipitated asphalt, whose softening point has not been increased.
Dependencies are inferred from the claim text.