DISTILLATION Dividing Wall Columns in …

1 Dividing Wall Columns in Petrochemical industry Taking Advanced DISTILLATION into the Modern Era Manish Bhargava -Director Advanced DISTILLATION GTC TechnologyK Shreya BPCL Mumbai ADVANCEDDISTILLATIONGTC Dividing Wall Columns ( GT-DWC ) Page 2 Most of the energy consumed in refineries is related to DISTILLATION . Advanced separation techniques make substantial reductions in energy consumption and improvement in product specifications GT-TDWC: Top Dividing Wall Columns GT-DWC : Middle Dividing Wall Columns GT-BDWC: Bottom Dividing Wall Columns GTC Single Shell Absorption / DISTILLATION ColumnPress AnnouncementPage 3 BPCL started 1st Top Dividing Wall Column in Isom Unit at Mumbai in March 2017 Heat Integrated GT-TDWC Page 4 Conventional side draw column provides limited opportunity for heat integration Top Dividing wall column gains the thermodynamic efficiency, plus affords meaningful heat (A,B,C)BFeed (A,B,C)BACC onventional Sidedraw ColumnGT-TDWC From ProcessCase Study 1.

2 GT-TDWC for Food Grade Hexane Production (FGH) for BPCL, IndiaPage 5 FGH production requires a narrow cut of an intermediate for application Conventional 2 Column System : DIH + FGH column Advanced DISTILLATION Option : GT-TDWC Conventional Option: DIH + New FGH ColumnPage 6 FGH ProductDIH ColumnLight IsomerateStable IsomerateFGH ColumnHeavyIsomerateTotal IsomerateComparison: GT-TDWC vs Conventional 2-Column SystemPage 7 DIH ColumnNewFGH Cost (MM USD/year )Steam Conventional 2 Column SystemMP Steam Consumption (1000 x lb/Hr) = Dividing Wall Column Installation at BPCL, IndiaPage 8 GTC Dividing Wall Columns ( GT-DWC ) Page 9 Most of the energy consumed in refineries is related to DISTILLATION .

3 Advanced separation techniques make substantial reductions in energy consumption and improvement in product specifications GT-DWC : Middle Dividing Wall Columns GT-TDWC: Top Dividing Wall Columns GT-BDWC: Bottom Dividing Wall Columns GTC Single Shell Absorption / DISTILLATION ColumnCase Study 2: Three Cut FCC Naphtha Splitter revamped to GT-DWCPage 10 GTC ConfidentialExisting Naphtha Splitter ConfigurationPage 11 Cut Point Range 288 to 388 FDepentanizer BottomsCut Point Range 161 to 373 FCut Point range 147 to 212 FCut Point Range 223 to 376 FObjectives for Revamp IncreaseFeedrate Reduceoverlapofheaviercomponentsinsidecu t 12 Bottlenecks in Column Design with Reference to New ObjectivesPage 13 Intermixing of Feed with Side CutSmaller Diameter puts a restriction on Vapor/Liquid LoadingHeavies ProductFeedOverhead ProductSidecutProductLCOHCOR evamp to GT-DWC Page 14 Heavies ProductFeedOverhead

4 ProductSidecutProductSidecutseparated from feed;Better qualityDividing Wall Column TraysPage 15 Installation of Dividing WallPage 16 GTC Internal Liquid Split Distributer Provision for external splitting for future useRisers for vapor flow Liquid split metering box (Maintains fixed liquid ratio on either side of wall)Page 17 Product Specs after Revamp to GT-DWC Page 18 ParameterUnitsNaphtha Splitter beforeRevampNapththaSplitter afterRevamp to GT-DWC Side DrawFlow Ratelb/hr398,000353,000D86 (IBP/FBP)Deg F223to 376231 to 356 Overlap (Heart Cut Naphtha D86 95%-Heavy Cut Naphtha D86 5%)Deg F9927 Project EconomicsPage 19 Client was planning to install a 2ndcolumn in sequence with the existing Naphtha Splitter.

5 A spare column was available for this retrofit. Cost of Revamp to GT-DWC was 1/4 of the alternate two-column design being explored by the Study 3 :Page 20 Existing Two Column FCC Naphtha Splitter Sequence revamped to GT-DWC Case Study 3: Two Columns Modified to Single ColumnFeedC5 NaphthaHCO / HP SteamLCO Heart Cut NaphthaHCO Heavy Naphtha 1 Heavy Naphtha 2LP SteamGenerator BFWPage 21 GTC ConfidentialDesign Features in Original Configuration Use of low temperature heat duty via LCO in NS1. This requires a side reboiler in NS1 Column Minimize duty in NS1 by taking a side cut stream to NS2 column Elevate pressure of NS2 Column to generate LP steamPage 22 GTC ConfidentialDesign Features in Original Configuration -Use of Low Temperature Heat Duty via LCO in NS1 Page 23NS1 Column has a side reboiler which allows use of low temperature heat dutyThe side reboiler forces a higher loss of C8s in the top product as the bottom section trays remain under from DepentanizerLight NaphthaLCO44 MMBtul/hr Heavy Oil54 MMBtu/hr Heavy NaphthaC8/C9 GTC ConfidentialDesign Features in Original Configuration

6 -Minimize Duty in NS1 by Taking a Sidecut to NS2 ColumnPage 24A Side stream as feed to NS2 Column lowers the energy consumption in NS1A Sidecut from NS1 forces higher C9 loss in Heavy Naphtha bottoms productFeed from DepentanizerLight NaphthaLCO44 MMBtu/hr Heavy Oil54 MMBtu/hr Heavy NaphthaC8/C9 GTC ConfidentialPage 25LP Steam generatorHeavy NaphthaHeavy Oil / HP SteamHeart CutNaphthaNS2 Column pressure is elevated to generate LP steam from the overhead vaporsHigher operating pressure decreases the relative volatility between different componentsLP steam is generated at the expense of higher HP steam and hot oil consumptionDesign Features in Original Configuration -Elevate Pressure of NS2 Column to Generate LP SteamRevamp to GT-DWC Heavy NaphthaFeedLightNaphthaLCOHCOH eart Cut NaphthaNaphtha Splitter-1 Revamped to GT-DWCSMN aphtha Splitter II IdledHeavy Naphtha 2 HCO / HP SteamHeart Cut NaphthaLP Steam GeneratorPage 26 Benefits of Revamp to GT-DWC Reduce utility consumption for the separation.

7 Produce heart cut naphtha in Naphtha Splitter-1 column, while removing Naphtha Splitter-2 from Design(NS-Iand NS-II)Naphtha Splitter-I afterRevamp to GT-DWC Feedlb/hr679,000679,000 Side DrawFlow Ratelb/hr363,700363,500D86 (IBP-FBP) F231-338231-337 Overlap (Side Cut D86 95%-Heavy Cut Naphtha D86 5%) HeatingDutyMMBtu/hr151111 Page 27 ParameterUnitsOriginal Design(NS-Iand NS-II)Naphtha Splitter-I after Revamp to GT-DWC Feedlb/hr679,000679,000C8/C9 (Naphthenes& Aromatics)lb/hr243,900243,900 Mid Cutlb/hr363,700363,500C8/C9 (Naphthenes& Aromatics)Concentrationwt% (Naphthenes& Aromatics)lb/hr232,404241,860% Recovery C8/C9 (Napthenes& Aromatics)wt%9598 Loss of C8/C9 (Naphthenes& Aromatics)lb/hr25,28018,230 Totalheating dutyMMBtu/hr151111 Comparison : Product Recoveries Existing Configuration vs GT-DWCPage 28 Benefits of GT-DWC Heating duty reduced by ~ 26% HP steam usage eliminated Naphtha Splitter-II is idled 3% Higher Product recoveries Heart Cut Naphtha obtained in Naphtha Splitter-I Project Payback (Based on Energy Reduction benefits only) = 10 MonthsPage 29 Case Study 4.

8 Grassroots Mixed Xylenes Recovery Unit at TonenGeneral (TG), Japan TG had an existing unit which produced C7+ product for gasoline blending. TG wanted to separate high purity petrochemicals (Toluene, Mixed Xylenes) from the feed. TG decided for a DWC solution against a two column configuration because of lower CAPEX and lack of plot 30 Case Study 4: Mixed Xylenes RecoveryPage 31GT-DWC for Mixed Xylenes RecoveryReformate FeedGT-DWC ColumnReformate LightCut ColumnReformate HeavyCut ColumnC5 richCutC6 Rich Cut to AromaticsTolueneMixedXylenesC9+ CutClay TreatersPage 32 Page 33 TolueneMixedXylenesC9+ CutFeed from Clay Treaters#17#103 TICFICTICR eformate LightCut ReboilerReformate HeavyCut ReboilerTX DWC is defined by three primary control loops Fixed reflux rate Side draw product rate cascaded to TI on upper tray Heating Duty cascaded to bottoms temperaturePrimary Control SchemeGT-DWC ColumnGT-DWC Column Internals at TonenGeneralPage 34 Off Center Dividing

9 WallTonenGeneral Mixed Xylenes Recovery UnitPage 35 Installation of GT-DWC Column at Chiba Refinery, JapanComparison : Two Column System vs DWC Page 36 Product SpecificationsTwo-column sequenceDWC configurationMix-xylenes product, lb/hr64,66564,670C8 aromatics, wt% duties, Reduction, 1000 x cost savings, %-25 Capital cost, $ Study 5: GT-LPG MAX for LPG RecoveryPage 37 Client Objectives Propane recovery in LPG > 97% No RefrigerationPage 38 Off Gas(C1,C2, C4, C4,Heavies)Fuel Gas(C1,C2)450 psigLPG (C3)C4, Heavies300 psig LPGR ecovery-55% Energy-22 MMBtu/hrConventional Design of LPG Recovery UnitPage 39 Off Gas(C1,C2, C4, C4,Heavies)Fuel Gas(C1,C2)LPG (C3)

10 C4, HeaviesOperating pressure = 300 psig LPG Recovery -97% Energy -20 MMBtu/hrInternal Circulation of Heavies as Absorption SolventGT-LPG MAX -Combined Absorption & DISTILLATION in a Single ColumnProject Economics of GT-LPG MAX Page 40 VariablesExisting ConfigurationGT-LPG Max Overall Propane Recovery %55 %97 %Total Duty MM 41 Unconventional DISTILLATION applications are an overlooked means to reduce refinery energy consumption GT-DWC reduces 20 30% OPEX through energy savings GT-DWC reduces 20 30% CAPEX by requiring a single column for multi-component separation Advanced DISTILLATION schemes can offer CAPEX and