Cloud point depressants (CPD) have been successfully used for many years in low-sulfur diesel fuels. For over ten years, custom-designed, specialty polymer chemistry has enabled refiners to meet cloud point (CP) guidelines with substantially less kerosene. This translates into greater refined yields through cut-point adjustment upgrades and the potential for diverting kerosene to more lucrative market opportunities, such as jet fuel.
The practice of cut-point downgrades to gas oil can be costly because diesel fuel generally has greater value. Kerosene dilutions have historically been as high as 30%-40% by volume with low-sulfur diesel fuels [1, 2]. While kerosene addition enables fuels to reach CP guidelines, it may negatively impact the fuel's energy content, cetane number, lubricity, flash point and density. Properly designed CP additives are able to substantially reduce or even eliminate the need for kerosene, thus substantially reducing refinery costs.
With ultra-low-sulfur diesel (ULSD) fuels being mandated throughout the mass market distribution system by June 2006, the need for CP control may be greater than ever. However, waxy crude and process limitations may make it difficult for refiners to economically make low cloud point ULSD. Fortunately, CPD can overcome these limitations without negatively impacting fuel characteristics. These additives allow refiners to meet low-temperature objectives while being neutral or beneficial to most other diesel fuel properties.