Increased flexibility of refineries by O 2 enrichment. Sulphur recovery and new opportunities. Janusz Kertynski, Dr Bernhard Schreiner Budapest, 13-14 October 2015 1
The Linde Group 2
Actual needs of refining industry Efficiency increase and process excellence Low prices of crude oil (sustainable?) Growing demand on gasoline in Europe Tighter environmental regulations Refining capacity growth in Asia and the Middle East Safety Flexibility Reliability Best possible utilization of existing infrastructure Revamps and investments in new infrastructure Need for low CAPEX solutions 3
Linde Gas Applications for refineries and petrochemical industry Inertization of tanks, terminals, railway tankers, road tankers etc. Nitrogen Services Purging, drying, pressure testing, temporary sourcing etc. Cryogenic condensation of volatile compounds Industrial water treatment e.g. ph adjustment with CO2 Reduction of NOx emission with use of Ozone Oxygen enrichment in Sulphur Recovery Units Oxygen enrichment of Fluid Catalytic Cracking Oxygen enrichment in process fired heaters (New development) 4
Typical gas applications for routine operation of Refinery Processes 5
Effect of oxygen enrichment on flow of process air 100 Overall flow with same amount of oxygen at different enrichment levels 90 Flowrate [m³/h] 80 70 60 50 40 30 20 10 Nitrogen Total flowrate 0 20 30 40 50 60 70 80 90 100 O2 concentration [%] 6
Oxygen enrichment in Sulphur Recovery Units Description of Claus Process for Sulphur Recovery Overall Chemistry: 2H 2 S + O 2 2S + 2H 2 O Acid Gas Air (Oxygen) 2H 2 S + 3O 2 Thermal Stage Burner 2SO 2 + 2H 2 O 2H 2 S + SO 2 3S + 2H 2 O RXN FURN WHB Catalytic Stages 2H 2 S + SO 2 3S + 2H 2 O To TGTU incinerator Reheaters Catalytic Converters Sulphur Condensers Sulphur pit 7
Oxygen enrichment in Sulphur Recovery Units 3 Modes Low level Enrichment Medium level Enrichment High level Enrichment (Double Combustion) Enrichment Up to 28 % Oxygen Up to 45 % Oxygen Up to 100 % Oxygen Add gaseous Oxygen (GOX) into existing air blower discharge Directly into combustion zone Stepwise into combustion zones (interstage cooling ) Adjustment at airbased Claus unit for revamp by O2 enrichment Insert oxygen injector into process air pipe Substitution of the airbased burner by new burner (SURE TM type) Substitution of airbased burner by new burner(sure TM type) & Various measures like e.g. installation of a second waste heat boiler Capacity Increase Up to 35 % Up to 75 % Up to 150 % 8
Oxygen enrichment in Sulphur Recovery Units Capacity Increase Capacity increase [%] 90 80 70 60 50 40 30 20 10 0 Capacity increase for Dp = constant (measured) 20 25 30 35 40 O2 [vol%] Case example: 3 CUs of same capacity are operated (max. Sulphur production 100 tons/day routinely all at a load of 80% of design capacity In case one CU faces shutdown the two other CUs left running can take over the load of the un-operated unit by applying O2e running at a load of 120 tpd 90% H2S CW 90% H2S measured 50% H2S CW 50% H2S measured 9
Oxygen enrichment in Sulphur Recovery Units Ammonia (NH 3 ) in Claus units Precipitation of ammonium salts acc. to NH 3 + H 2 O + SO 2 NH 4 HSO 3 Often causes: Reduced plant availability Less Sulphur recovery efficiency Enhanced effort for plant maintenance Reduced throughput Remedy: Improvement of Claus furnace operation Increased temperature Higher residence time Better mixing of the reactants O 2 enrichment to be considered 10
Oxygen enrichment in Sulphur Recovery Units Ammonia (NH 3 ) in Claus units Measurements Measured Ammonia destruction effects NH 3 [vppm] 300 Air, 21 vol.-% O 2 Enriched air, 27-28 vol. -% O 2 200 100 Sampling of Claus process gas 0 A B C D E Different Claus units 11
Oxygen enrichment in Sulphur Recovery Units Hydrogen savings at the tailgas unit (SCOT-type) Enhanced H 2 partial pressure in the Claus process gas reduces fuel gas consumption at the tailgas unit Trial results - mode 1: H 2 demand * AG + SWS gas + Air 100 % AG + SWS gas + Air (less) + O 2 (i.e. 26% enriched) 73 % Trial results - mode 2: H 2 demand * AG + Air 100 % AG + Air (less) + O 2 (i.e. 26% enriched) 62 % * Amount of H 2 to be added up-stream the hydrogenation step 12
Oxygen enrichment in Sulphur Recovery Units Hydrogen savings at the tailgas unit (SCOT-type) Central process control system Controller Gaseous Oxygen (GOX) Measuring and control unit O 2 analyzer Tank / vaporizer Air Equipment in refinery Equipment to be delivered by Linde Gas distributor Air and oxygen to Claus main burner 13
Oxygen enrichment in Sulphur Recovery Units Trials with O 2 enrichment (Low level): Scope & hardware Service offer: Consulting/Studies Identification/verification of needs and bottlenecks Realisation of field trials out of one hand with low cost Tailored hardware solutions for oxygen supply/dosing/injection Ammonia services (sampling/analysis) Trial report and recommendation of target/fixed solution OXYMIX TM Flowtrain and controller at the plant site OXYMIX TM Injector for safe and efficient mixing of oxygen into the process air Portable tank (ISO Container) and containerised vaporiser 14
O 2 enrichment in FCC Processing Off-gas Crack gas Steam Steam 1 Gasoline 3 4 2 Gasoil Residue Regeneration air Oxygen 5 Vacuum gas oil Recycle oil 1. FCC reactor 2. Regenerator 3. Boiler 4. Fractionation 5. Recycle oil 15
O2 enrichment in FCC Processing Oxygen enrichment at the FCC regenerator is typically applied: If the air blower of the regeneration is limiting If the velocity in the regenerator is too high - abrasive effects and catalyst losses For increase of throughput of FCC feed Oxygen enrichment at the FCC regenerator is proven technology which has the potential to: Increase flexibility towards heavier feeds, load changes and light products Increase capacity Reduce catalyst losses Improve economy substantially 16
Oxygen enrichment in process furnaces OPF General process description Idea Use Oxygen to improve furnace performances with low CAPEX: Higher capacity Higher efficiency Less NOx Technology Basis Injection of Oxygen stream in new burners or existing ones with specific layout. When?/Benefits Capacity increase Better flexibility reduced influence of fuel composition changes Solving draft problems (overpressure issues) Improving flame stability - avoid impingement and big flames Higher fuel efficiency due to reduced amount of flue gas and improved exchange in convection section Suitable for both natural draft and forced draft systems 17
Oxygen enrichment in process furnaces - OPF Scope and services Consulting/Studies Identification/verification of needs and bottlenecks Design review of the furnace (Linde Gas + Linde Engineering) Equipment supply (OXYMIX TM Flowtrain + OXYMIX TM Injector, burners) Burner testing Assistance for start-up Performance monitoring Gas supply Linde burner design and test center - Italy 18
Oxygen enrichment in refining processes Summary Oxygen enrichment comes with Increased plant capacity Increased flexibility (technically and conceptually) Potential fuel savings Improved combustion e.g. NH 3 destruction in Claus units Low CAPEX Claus O2 enrichemnt trials Refinery LOTOS 2014 19
Contact information: Dr Bernhard Schreiner - Bernhard.Schreiner@linde-gas.com Janusz Kertynski janusz.kertynski@pl.linde-gas.com Thank You
Back-up Oxymix 21
Back-up OPF - Impact on NOx emission Typic. Heater vs O2 Enriched heater Typ. O2 Enrich. H.R. ( MW) 1.43 1.43 O2 in C.A. ( %v) 21 24 NG flow (kg/hr) 108 108 O2 flow (Nm³/h) 0 52 Air flow (Nm³/h) 1600 1200 Pressure drop 100% 75% NOx emissions 100% 76% NOx Reduction possible - Induced stratified combustion and induced flue gas recirculation due to specific layout and burner design 22