Crude oil Treatment process Hydrotreatment Sulfur recovery Amine recovery

Hydrotreating A number of contaminants are found in crude oil. As the fractions travel through the refinery processing units, these impurities can damage the equipment, the catalysts and the quality of the products. There are also legal limits on the contents of some impurities, like sulphur, in products. Hydrotreating is one way of removing many of the contaminants from many of the intermediate or final products. In the hydrotreating process, the entering feedstock is mixed with hydrogen and heated to 300 – 380 oC. The oil combined with the hydrogen then enters a reactor loaded with a catalyst which promotes several reactions: Hydrogen combines with sulphur to form hydrogen sulphide (H2S). Nitrogen compounds are converted to ammonia. Any metals contained in the oil are deposited on the catalyst. Some of the olefins, aromatics or naphthenes become saturated with hydrogen to become paraffins and some cracking takes place, causing the creation of some methane, ethane, propane and butanes. 2

Hydrotreating 3

Hydrotreatment Remove contaminants from many of the intermediate or final products. Feedstock is mixed with hydrogen and heated to 300 - 380oC. The oil combined with the hydrogen then enters a reactor loaded with a catalyst which promotes several reactions: - Hydrogen combines with sulphur to form hydrogen sulphide (H2S) - Nitrogen compounds are converted to ammonia - Metals contained in the oil are deposited on the catalyst - Some of the olefins, aromatics or naphthenes become saturated with hydrogen to become paraffins - Some cracking takes place, creating methane, ethane, propane and butanes.

Hydrotreatment Remove: contaminants such as sulfur, nitrogen, condensed ring aromatics, or metals Feedstocks: range from naphtha, solvents, distillate fuels, residual fuels, vacuum residuum Product: mainly used as environmentally acceptable clean fuels.

Hydrotreater GTC Technology

Feedstock - treatment Residual fuels: Hydro-desulfurization (HDS) since the sole object is sulfur removal. Other than residual fuels :Hydrofining. improve the odor, color, stability, combustion characteristics, removes sulfur, nitrogen and other nonhydrocarbon In the catalytic cracking feed stocks: Hydrofining significantly improves cracking quality. Carbon yield is reduced, gasoline yield is increased The need for low sulfur residual fuel oils to alleviate the air pollution problem has led to the development of the required hydrotreating technology.

Difference between Hydrotreating and hydrocracking Hydrotreating and hydrocracking both can be called as Hydroprocessing

Naphtha Hydrotreating Objectives Sulphur Reduced to less than 0.5 wt ppm. Nitrogen Metals Reduced to ppm levels. Oxygen/Water Reduced to less than 1 wt ppm Olefins & di-olefins Saturated to avoid exchanger fouling and reactor coking

Diesel Hydrotreating Objectives Sulphur Reduced to between 0.2 - 0.02 wt%   Nitrogen - Reduced as much as possible  Cetane - An improvement of 1-3 cetane numbers   Aromatics/polyaromatics   Stability - Olefins are saturated.

Guard Reactor

Increasing Difficulty Desulfurization Increasing Difficulty

Denitrogenation More complex reaction

Oxygen Removal

Olefin Saturation Very rapid and exothermic reaction

Aromatic Saturation

Hydrotreater BP-UK