Crude Distillation Chapter Updated: August 11, 2016 Copyright © 2016 John Jechura (jjechura@mines.edu) Gases Polymerization Sulfur Plant Sat Gas Plant Gas Sulfur LPG Fuel Gas Butanes Alkyl Feed LPG Alkylation Polymerization Naphtha Gas Separation & Stabilizer Isomerization Light Naphtha Alkylate Aviation Gasoline Automotive Gasoline Isomerate Reformate Naphtha Hydrotreating Heavy Naphtha Solvents Naphtha Reforming Naphtha Atmospheric Distillation Jet Fuels Crude Oil Kerosene Kerosene Desalter Distillate Hydrocracking AGO LVGO Gas Oil Hydrotreating Fluidized Catalytic Cracking Cat Naphtha Solvents Distillate Hydrotreating Cat Distillates Vacuum Distillation Treating & Blending Heating Oils Diesel Fuel Oil HVGO Cycle Oils Residual Fuel Oils DAO Solvent Deasphalting Visbreaking Vacuum Residuum Coker Naphtha Heavy Coker Gas Oil SDA Bottoms Asphalts Naphtha Distillates Fuel Oil Bottoms Lube Oil Lubricant Greases Solvent Dewaxing Waxes Waxes Coking Light Coker Gas Oil Coke Updated: August 11, 2016 Copyright © 2016 John Jechura (jjechura@mines.edu) U.S Refinery Implementation EIA, Jan 1, 2016 database, published June 2016 http://www.eia.gov/petroleum/refinerycapacity/ Updated: August 11, 2016 Copyright © 2016 John Jechura (jjechura@mines.edu) Page 3 Topics Crude Stills Historically the oldest refining process Only the first step in crude oil processing Purpose To separate crude oil into narrow That more closely resemble final Are more appropriate for feeds to upgrading operations Updated: August 11, 2016 Copyright © 2016 John Jechura (jjechura@mines.edu) 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 650F Product Yield Curves Cut Point, Overlap, & Tails T C P D Cut TBP IBP (oF) TBP EP (oF) Light Naphtha (LSR Gasoline) 80 to 90 180 to 220 Heavy Naphtha 180 to 220 330 to 380 Middle 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 Vacuum Resid 950 to 1100 Updated: August 11, 2016 Copyright © 2016 John Jechura (jjechura@mines.edu) Atmospheric & Vacuum Tower Complex Modified drawing from: R Updated: August 11, 2016 Copyright © 2016 John Jechura (jjechura@mines.edu) Sutikno, PTQ ,Q2 2015 Atmospheric Column with Preflash M I Updated: August 11, 2016 Copyright © 2016 John Jechura (jjechura@mines.edu) Musumeci, Stupin, Olson, & Wendler, PTQ, Q2 2015 10 Preflash Options Tight Oil Example with no AGO • • Simple Preflash drum Vapors bypass heater Optimising • • • L Semi-preflash column Some fractionation Final fractionation done in top of main fractionator • • • Full Preflash column All distillate bypasses main fractionator Separate condenser system PTQ, Q3 2015 Updated: August 11, 2016 Copyright © 2016 John Jechura (jjechura@mines.edu) 11 Feed Preheat Train & Desalter Feed Preheat Train Desalter Initial heat exchange with streams from within the tower Temperature carefully selected water vaporize Heat recovery important to distillation economics! o o First absorb part of the overhead condensation load Exchange with one or more of the liquid sides streams, beginning with the top (coldest) side stream Require flexibility o o o Changes in crude slate Temperature at desalter Limits on two-phase flow through network Final heating in a direct fired heater Heat enough to vaporize light portions of the crude but temperature kept low to minimize thermal cracking o o Inlet typically 450 to 550F Outlet 600 to 750F Heavier crudes cannot be heated to the higher temperatures Updated: August 11, 2016 Copyright © 2016 John Jechura (jjechura@mines.edu) not let Lighter crudes (> 40API) @ 250F Heavier crudes (< 30API) @ 300F All crudes contain salts (NaCl, MgCl Salt present in the emulsified water Treated in the field with heat & chemicals to break oil water emulsions Salt can cause damage to equipment o o o Scale in heat exchangers HCl formation can lead to corrosion Metals can poison refinery catalysts Remove salts & dissolved metals & dirt Oil mixed with fresh wash water & demulsifiers Separation in electrostatic settling drum Wash water up to 10% of crude charge ~ 90% of the water can be recovered Effluent water treated for benzene 12 Crude Electrostatic Desalting Drawing by Milton Beychok http://en.citizendium.org/wiki/File:Desalter_Diagram.png BFDs from: Refining Overview Petroleum Processes & Products, by Freeman Self, Ed Ekholm, & Keith Bowers, AIChE CD-ROM, 2000 Updated: August 11, 2016 Copyright © 2016 John Jechura (jjechura@mines.edu) 13