HYDROGEN UNIT CHAPTER-1 INTRODUCTION. The process for hydrogen generation involves the following four major steps.

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1 CHAPTER-1 INTRODUCTION 1.1 GENERAL The Panipat Refinery Hydrogen Unit is designed to produce 38,000 MTPA of high purity (99.99%) hydrogen gas based on 8,000 hours on-stream operation to cater to the OHCU/DHDS/CCR unit requirement for various chemical reactions. This hydrogen plant is only the third of its kind among refineries in India. Hydrogen is produced in the unit by Steam Reforming of Naphtha based on the technology from M/S Haldor Topsoe A/S, Denmark. The process for hydrogen generation involves the following four major steps. Sulphur removal from Naphtha. Steam reforming of Naphtha Medium and low temperature shift conversions. Hydrogen purification in a PSA unit. Different type of catalyst/adsorbents is used in each of the above four sections. As the process involves high temperature condition in steam reforming so the waste heat is utilized in generation of large quantity of steam. The steam generated in the unit is used for captive consumption and the surplus is exported to the Refinery Header. The pressure swing absorption (PSA) system comprising of 10 bed absorbers, valve skids, PLC based control system, is based on M/S UOP technology. The control system supplied by M/S UOP integrates the high severity reformer with PSA purification system to provide an optimum design. 1.2 PLANT CAPACITY/TURN DOWN Hydrogen unit design capacity : : On stream factor : : 38,000 MTPA of Hydrogen 52,800 NM 3 /HR 8000 HRS./YR 30% of the design capacity for the reformer = 11,400 MTPA Hydrogen = 15,835 NM 3 /HR PSA can operate from 0 to 100% capacity and produce the hydrogen of the same purity. CHAPTER-1 1/13

2 1.3 UNIT DESIGN SPECIFICATION FEED STOCK QUALITY The feed stock for hydrogen unit is straight run Naphtha, obtained from either Arab Mix (AM) or Bombay (BH) Crude. There is also provision to route hydrocracker light naphtha to hydrogen unit feed tanks. The typical quality of Arab Mix Naphtha and Bombay High Naphtha is as follows. PROPERTY ARAB MIX NAPHTHA BOMBAY HIGH NAPHTHA 1. Specific gravity (a) Total sulphur, PPMW (b) Chlorine, PPMW (c)o2, PPMW <2 2-5 <2 3. Mercaptan, sulphur, PPMW 4. Sulphur as H2S, PPMW 5-10 <5 5. Nitrogen, PPMW 1 6. Molecular weight Carbon to hydrogen ratio wt/wt Calorific value (gross), 11,480 11,420 Kcal/Kg C KG/CM Hydrogen type (Vol. %) Parafins Olefins Naphthenes Aromatics TBP cut range C5-90 C ASTM distillation D-86 IBP 10 Vol. % 50 Vol. % 70 Vol. % End Point BATTERY LIMIT CONDITION FOR FEED STOCK Battery limits condition for Naphtha feed. Feed stock source- Storage tanks 3 Nos. (5000 KL each) CHAPTER-1 2/13

3 MIN. NORMAL MECH. DESIGN Feed stock pressure, KG/CM 2 G Feed stock temperature, C Ambient BATTERY LIMIT CONDITIONS FOR HYDROGEN RICH GAS A. B/L conditions for Catalytic Reformer Hydrogen rich gas. MIN. NORMAL MECH. DESIGN Feed stock pressure, KG/CM 2 G Feed stock temperature, C B. Composition of Catalytic Reformer rich gases The typical composition of hydrogen rich gas from CRU is as follows. Composition, Mole % Hydrogen CH C2H C3H i- C4 H n- C4 H C C5+ components consist of n-c5h12, I-C6H14, C8H18, n-heptane, cyclopentane, methylcyclopentane, benzene, toluene, C8 aromatics, and C9 aromatics. The hydrogen rich gas is saturated at 0 C and a pressure of 24 KG/CM 2 G in CRU before reaching hydrogen. Expected flow rate of CRU hydrogen rich gas, MT/HR-Max PRODUCT QUALITY The plant is designed for a stable operation between 30% and 100% of the design flow rate and producing H2 of the specified purity. Purity Vol. % minimum Impurities CO, CO2 and CH4 15 PPM maximum Nitrogen Product battery limit conditions Pressure, KG/CM 2 G 20 Temperature C 40 CHAPTER-1 3/13

4 1.3.5 UTILITIES STEAM Steam is available at the battery limits of the unit at the following conditions. (a) (b) (c) HP steam Pressure, KG/CM 2 G Temperature C MP steam Pressure, KG/CM 2 G Temperature C LP steam Pressure, KG/CM 2 G Temperature C MIN. NORM MAX MECH DESIGN MIN. NORM MAX MECH DESIGN MIN. NORM MAX MECH DESIGN CONDENSATE Pressure, KG/CM 2 G Temperature C MIN. NORM MAX MECH DESIGN POWER Power for electric drives and lighting are volts, 3 phases, 50 cycles per second frequency grounded system for drives of 160 KW and above volts, 3 phases, 50 cycles per second frequency for drives up to 160 KW, neutral is solidly earthed. 3. For lighting-240 volts, single phase, 50 cycles per second frequency V AC UPS shall be available for hydrogen unit instruments and control systems. CHAPTER-1 4/13

5 COOLING WATER NORMAL MAXIMUM ph Turbidity NTU Total dissolved Solids, PPM MO alkalinity as CaCO3 PPM Total hardness as CaCO3 PPM Ca hardness as CaCO3 PPM Total chlorides as CI, PPM Sulphates as CaCO3 PPM Silica as SiO2, PPM Organophosphate as PO4, PPM Zinc sulphate as Zn4 PPM Free residual chlorine, PPM Polymeric dispressant, PPM MO alkalinity will find its own level depending upon ph maintained. At ph 7.5 to 8.0, MO alkalinity is CaCO3 will be about 100 to 120 mg/l. B/L CONDITIONS MIN NORM MAX MECH. DESIGN Supply pressure, KG/CM 2 G Return pressure, KG/CM 2 G Supply temp C Return temp C DM WATER DM WATER QUALITY ph Turbidity, NTU Total dissolved solids, PPM <0.1 Total hardness as CaCO3, PPM Collidal silica as SiO2, PPM <0.005 Total silica as SiO2, PPM <0.02 Total chlorides as Cl, PPM Total iron as Fe, PPM <0.01 Copper, PPM <0.005 Conductivity at 20 C <0.2 umho/cm Oil, PPM CHAPTER-1 5/13

6 B/L CONDITIONS MIN. NORM. MAX. MECH DESIGN Pressure, KG/CM 2 G Temp C - AMB BOILER FEED WATER BFW available at about 120 C and 58 Kg/cm2g for HP consumers and at 120 C and 28 Kg/cm2g for MP/LP consumers FUEL GAS Fuel gas from the refinery fuel gas network is available at battery limit at the following conditions. Gross calorific value, Kcal/Kg 10,948-11,786 Pressure, Min/Norm/Max, Kg/cm2g 2.5/3.0/3.5 Pressure, Mech. Design, Kg/cm2g 7.0 Temperature, Normal, C 40 Temperature, Mech. Design, C 65 The typical composition of fuel gas is as given below. Composition Vol% H C C C2= C C3= C C4= C H2S H2O O CO N Molecular Weight Flow, MT/h Max-3.0 CHAPTER-1 6/13

7 AIR A. Instrument Air BATTERY LIMIT CONDITION Dew point, C Oil content, PPM 15 at operating pressure 40 at atmospheric pressure MIN. NORM. MAX MECH. DESIGN Pressure, KG/CM 2 G Temperature C B. Plant Air Dry, Oil Free Dew point, C Oil content, PPM No free moisture BATTERY LIMIT CONDOTION MIN. NORM. MAX MECH. DESIGN Pressure, KG/CM 2 G Temperature C For air supply to instruments inside control room, group filter and reducers are provided 2. For air supply to instruments in the field, individual combined filter and reducer with integrally mounted pressure gauge of 40-mm dial are provided. 3. The air supply to all the pneumatic instruments are at 1.4 Kg/cm2g INERT GAS Nitrogen generated from air separation in a cryogenic nitrogen plant is available at the battery limit at the following conditions. Battery limit Conditions NORMAL MECH. DESIGN Pressure, KG/CM 2 G Temperature C CHAPTER-1 7/13

8 FIRE FIGHTING WATER NORMAL Pressure, KG/CM 2 G 7.0 Temperature C EFFLUENTS WASTE WATER Process waste water Continuous basis to oily water sewer by gravity. Storm water Storm water sewer Floor washings Contaminated rain water sewer Waste water disposal By gravity Spent caustic Routed to spent caustic disposal system Sour water Sour water stripping unit Boiler blow down Routed to storm water sewer after cooling BLOW DOWN AND FLARE 1. Process drain is routed to either OWS or closed blow down vessel. Closed blow down facilities with a blow down vessel and pump out arrangements to slop tanks is provided in the unit. 2. All hydrocarbon/combustible gases and vapours are relieved to the flare. NORMAL MAX MECH. DESIGN Flare header back pressure, KG/CM 2 G Gaseous emission shall be with in the following stipulations. 1. Particulate matter <125 MG/M 3 2. Hydrocarbons <25 PPM 3. Mercaptans <25 PPM 4. H2S <50 PPM 5. Nox <100 PPM 1.4 CHEMICALS The following chemicals are used for treatment of condensate/dm water. Hydrazine Moropholine Trisodiumphosphate CHAPTER-1 8/13

9 1.5 CATALYST DMDS is used for injection into the process Naphtha System during processing of Bombay High Naphtha Amine water (9%), KG/Year 70,000 Hydrozine, KG/Year 180 (As N2 H4) Phosphate solution, KG, Year (as PO4) 240 The following catalysts are used in the unit. 1. TK-550 Hydrogenation catalyst 2. HTZ-3 S-absorption catalyst 3. RKNGR Adiabatic pre-reforming catalyst 4. R-67-7H Reforming catalyst 5. LK-811 MT shift catalyst 6. LK LT shift catalyst 7. H1, H2-6, H3, H5, H1-5 PSA adsorbent 1.6 EQUIPMENT LIST EQUIPMENT NO. RB-201 RB-202A/B RB-203 RB-204 RB-205 DESCRIPTION REACTORS Hydrogenator Sulphur Adsorber Pre-reformer MT shift converter LT shift converter VESSELS V-201 HP Steam Drum V st Process Condensate Separator V nd Process Condensate Separator V-204 Deaerator V-205 Naphtha Feed Surge Drum V-206 S.U.K.O Drum For HDS and Flare V-207 Blow Down Drum V-208 Phosphate Injection Drum V-209 Amine Water Injection Drum V-210 Hydrazine Injection Drum V-211 Mixing Tank V-212 Measuring Bottle V-214 Condensate Pot For E-214A/B V-220 Condensate Pot For E-220 CHAPTER-1 9/13

10 V-221 Condensate Pot For E-221 V-222 Naphtha Fuel K.O. Drum V-223 Fuel gas K.O. drum V-224 Fuel Naphtha Recycle Pot V-225 K.D. Drum For CRU Gas V-231 Start Up KO Drum For Shift Section V-232 Hydrogen Emergency Buffer Vessel V-238 Flare K.O. Drum V-239 Closed Blow Down Vessel V PSA Adsorbers V-320 PSA Surge Tank EXCHANGERS E-201 Reformer Feed reheat Coil E-202 Pre-reformer Feed Preheat Coil E-203 HP Steam Superheat Coil E-204 Convection Section Boiler Coil E-205A/B/C Combustion Air Preheat Coils E-206 Waste Heat Boiler E st BFW Pre-heater E nd BFW Pre-heater E rd BFW Pre-heater E-210 Deaerator Re-boiler Coil E-211 DMW Pre-heater E-212 Water Cooler E-213 Combustion Air Pre-heater E-214A/B Naphtha Feed Vaporizer E-215 Naphtha Feed Pre-heater E-216 Boiler Blow Down Cooler E-220 Naphtha Fuel Vaporizer E-221 Fuel gas Pre-heater E-222 Fuel Naphtha Recycle Cooler E-230 S.U. N2 Heater For HDS Section E-231 S.U. N2 Cooler For HDS Section E-232 Start up Heater For Shift Section E-233 Start up Cooler For Shift Section E-234 Shut Down Cooler PUMPS P-201A/B Naphtha Feed Pump P-202A/B HP BFW Pump P-203A/B MP BFW Pump P-204A/B Phosphate Dosing Pump P-205A/B Amine Water Dosing Pump P-206A/B Hydrazine Dosing Pump P-207 DMDS Pump P-208 Fuel Naphtha Recycle Pump CHAPTER-1 10/13

11 KA-201 KA-202 KA-203A/B KA-204 KA-205 KA-206 KA-207 FF-201 FANS & COMBUSTION Combustion Air Blower Glue Gas Fan Recycle Gas Compressor S/U Compressor For HDS Section S/U N2 Compressor Hydrogen Compressor S/U H2 Recycle Compressor FURNACE Reformer Furnace 1.7 MATERIAL BALANCE AM NAPHTHA FEED INPUT OUTPUT Naphtha Feed= MT/HR Hydrogen =4.75 MT/HR Steam = MT/HR PSA Off Gas = MT/HR MT/HR Condensate = MT/HR V V Total MT/HR REFORMER FURNACE INPUT OUTPUT Naphtha Fuel =1.219 MT/HR Flue Gas = MT/HR Fuel Gas =3.000 MT/HR Combustion Air = MT/HR PSA Off Gas= MT/HR MT/HR CHAPTER-1 11/13

12 TYPICAL STREAM COMPOSITION (VOL%) Case: Arab Mix Naphtha feed at 100% of the Design Capacity Components Pre- Reformer Inlet Reformer Inlet MT Shift Reactor Inlet HT Shift Reactor Inlet PSA Inlet PSA Off Gas Hydrogen Product Hydrogen Carbon monoxide Carbon dioxide Methane C2-C components Naphtha S. No Reactor No. Service 1. RB-201 Hydrogenato r 2. RB- 202A 3. RB- 202B Sulphur Adsorber Sulphur Adsorber Catalyst Type Particle Size, MM Catalyst Loaded Volume, M 3 Catalyst Expected Life, Year Bottom Layer TK-550 5, Rings mm, balls HTZ-3 4, Extrudat es HTZ-3 4, Extrudat es Months 100mm balls for upper & lower beds Months 2-4 lumps at the bottom 4. RB-203 Pre-reformer RKNGR 4.5X FF-201 Reformer R-67-7H 16X11.7 holes mm balls Catalyst Support Material Top Layer 100mm, balls 100mm balls for upper & lower beds 100m 1 alumina balls and 100mm alumina balls. 200 mm balls CHAPTER-1 12/13

13 S. No Reactor No. Service 6. RB-204 MT shift catalyst 7. RB-205 LT shift catalyst Catalyst Type Particle Size, MM Catalyst Loaded Volume, M 3 Catalyst Expected Life, Year LK X mm balls LK LSK 4.5X X (MT) 5 5 Catalyst Support Material 200 mm balls CHAPTER-1 13/13