Overview Purpose To recover light materials. Fractionate into sharp light fractions. CRUDE DISTILLATION Configuration May be as many as three columns in series Crude Stabilizer/Preflash Column Reduce traffic in the Atmospheric Column Atmospheric Column Vacuum Column Reduced pressure to keep temperatures below 650 o F Crude Oil Fractionation / Distillation Crude oil is heated to 750 o F (400 o C) Heated crude is separated into rough "cuts Different boiling point are drawn from the distillation tower. Light compounds (fuel gas and LPG) rise to the top of the tower, Heavy material (asphalt) falls to the bottom of the tower. Petroleum Refining Operations. Petroleum refining begins with the distillation, or fractionation, of crude oils into separate hydrocarbon groups like Light ends, naphtha/gasoline kerosine diesel and residue etc. The resultant products are directly related to the characteristics of the crude processed.(t 650 750 deg o F) or (310 o C 350 o C) Most distillation products are further converted into more usable products by changing the size and structure of the hydrocarbon molecules through cracking, reforming, and other conversion processes. data:text/html;charset=utf 8,%3Ctable%20width%3D%2280%25%22%20border%3D%220%22%20align%3D%22center%22%20cellpadding%3D%220%22%2 1/5
Fig 1.10 Atmospheric Distillation [19] Fig:1.11 Typical Configuration Atmospheric Column w/o Preflash [19,20] data:text/html;charset=utf 8,%3Ctable%20width%3D%2280%25%22%20border%3D%220%22%20align%3D%22center%22%20cellpadding%3D%220%22%2 2/5
Fig:1.12 ADU & VDU OVERVIEW [24,25] Wash Zone Couple trays between flash zone & gas oil draw. Reflux to wash resins & other heavy materials that may contaminate the products. Condenser Typically 0.5 to 0.2 psig. Balancing act Low pressure reduce compression on overhead system. High pressure decrease vaporization but increases flash zone temperature & furnance duty: affects yields. Pumparounds Reduces overhead condenser load & achieves more uniform tower loading. provides liquid reflux below liquid draws. Side draws & strippers cut point related to final boiling point of draw steam. data:text/html;charset=utf 8,%3Ctable%20width%3D%2280%25%22%20border%3D%220%22%20align%3D%22center%22%20cellpadding%3D%220%22%2 3/5
Side strippers remove light component tail & return to main column. Steam strippers traditional. Reboiled strippers reduce steam usage & associated sour water. Trays & pressure profile [19,20,24,25] Typically 32 in tower 0.1 to 0.2 psi per tray. Condenser & accumulator 3 to 10 psi across condenser liquid static head in accumulator. Typically 6 to 16 psi across entire column. Fig:1.13 A typical configuration of Atmospheric column with stripping section and reflux drum arrangement. data:text/html;charset=utf 8,%3Ctable%20width%3D%2280%25%22%20border%3D%220%22%20align%3D%22center%22%20cellpadding%3D%220%22%2 4/5
Fig:1.14 [19] A typical configuration of two stage hydrocracking unit. Table:1.4 Typical Crude Tower Cut Points [19,20] CUT TBP IBP( o F) TBP EP( o F) Light Naphtha(LSR Gasoline) 80 to 90 180 to 220 Heavy Naphtha 180 to 220 330 to 380 Distillate (Kerosene) 330 to 380 420 to 520 AGO(Atm Gas Oil) 420 to 520 650 LVGO(Light Vac Gas Oil) 650 800 HVGO(Heavy Vac Gas Oil) 800 950 to 1100 Vaccum Resid 950 to 1100 data:text/html;charset=utf 8,%3Ctable%20width%3D%2280%25%22%20border%3D%220%22%20align%3D%22center%22%20cellpadding%3D%220%22%2 5/5