ENERGY EFFICIENCY IMPROVEMENT in Refineries and Petrochemical Plants

Unit Operations in Process Plants  Distillation / Evaporation  Heat Transfer  Pumping and Compression  Filtration / Crystallisation  Chemical reaction processes

Energy Minimisation in Distillation  Typically distillation is a maximum energy consuming unit operation deployed in Refineries and Petrochemicals  Energy Requirement : 40 – 60 % of the total Energy

Energy Minimisation in Distillation  Distillation at low pressure  Maximizing Pump Arounds in Petroleum type distillation  Compensating seperation with increased no of stages as Pump Arounds will reduce internal reflux  Drawing products/Pump Arounds at maximum temperature for preheating feed/utilities.  Optimisation of Stripping steam / overflash

Energy Minimisation in Distillation Overhead Heat Integration GAS FEED Preferred for super fractionators and also in crude distillation

Energy Minimisation in Distillation

Conventional Process GAS FEED Example:-1 Butene Separation process Energy Minimisation in Distillation

Heat Coupled Process Example:-1 Butene Separation through Heat Coupled Process Energy Minimisation in Distillation FEED

Heat Coupling in Distillation GAS FEED Example:-In super fractionator or distillation column operating with high R/R, above type of Heat coupling is beneficial Energy Minimisation in Distillation

Multiple Heat Coupling GAS Example:- Xylene Column of Px Plant REB-1 REB-3 REB-2 Energy Minimisation in Distillation

Vapour Compression in Distillation GAS Energy Minimisation in Distillation

Vapour Compression in Distillation FEED Energy Minimisation in Distillation

Vapour Compression in Distillation

Energy Minimisation in Distillation Vapour Compression in Distillation

Low Temp heat integration in Distillation column Conventional FEED Energy Minimisation in Distillation Steam reboiler 190 C

Low Temp heat integration in Distillation column FEED Energy Minimisation in Distillation To Crude Preheat Train

Energy Minimisation in Crude/Vacuum Distillation  Overhead Integration  Maximisation Pump Arounds  Introduction of top PA  Use of Pretopper  Low column pressure  Avoid successive distillation and try to draw product from same distillation column.

Top Pump Around crude integration FEED Energy Minimisation Crude/Vacuum Distillation Crude PA’s are maximised to reduce R/R and seperation is compensated by higher nos of stages

Conventional stripping of CLPS Stream CLPS LIQ Energy Minimisation in Hydrotreaters/ Hydrocrackers FRACTIONATOR GAS to LE Section STABILISER

Energy Minimisation in Hydrotreaters/ Hydrocrackers

Adding Stripper ahead of Main Fractionators CLPS LIQ Energy Minimisation in Hydrotreaters/ Hydrocrackers STEAM MP STRIPPER FRACTIONATOR  Eliminate WGC  Reduce reboil requirement for stabiliser/de-ethaneiser GAS

Energy Minimisation in Hydrotreaters/ Hydrocrackers

Addition of heat exchangers /steam generators in between successive reactors FRACTIONATOR Energy Minimisation in Hydrotreaters/ Hydrocrackers HPS CLPS LIQ FEEDRG

Energy Minimisation in Hydrotreaters/ Hydrocrackers  Even Steam Generators can be installed to recover heat of individual reactors  Utility generation in HP heater convection to increase efficiency of HP furnaces

CHPS/HHPS CLPS/HLPS 160 Kg/cm2g Pressure RT Cascaded with drives of feed pump to provide around 30% pump power drive Energy Minimisation in Hydrotreaters/ Hydrocrackers PRT HHPS/CHPS HLPS/CLPS 25 kg/cm2g

WASH WATER GAS CONVENTIONAL DESIGN CHPS 55 – 60 C Rx EFFLUENT AIR COOLER RGC Energy Minimisation in Hydrotreaters/ Hydrocrackers HEATER FRACTIONATOR CLPS

Use of HHPS to conserve heat instead of CHPS WASH WATER R GAS CHPS 55 – 60 C Rx EFFLUENT AIR COOLER RGC MODIFIED ENERGY EFFICIENT DESIGN Energy Minimisation in Hydrotreaters/ Hydrocrackers ~180 C HHPS HLPS ~180 C FRACTIONATOR CLPS

Very Low Temp heat integration  Hot products are cooled by tempered water coolers and the tempered water is cooling with heating of DM Water before feeding to Deaerators  Overall pinch to improve plant efficiency / Grand composite Energy Minimisation Refinery

Energy Minimisation in Coker  Efficient integration of feed preheat circuit  Maximisation of Hot feed streams  Recovery of Blowdown tower off gases

Energy Minimisation in FCCU  Maximize Main Column Bottom Pump Around to heat feed /raise BFW  PRT for air blower ---Regen. Flue Gas  PRT provides part of power to drive main air blower  Two stage regeneration --- First stage: 2C+O 2 =2CO  CO incinerator --- Second stage:2CO+O 2 =2CO 2  Feed Preheat improvement

Energy Minimisation in other processes  Separation done through Molecular Sieve or Membrane separation technology as a substitute of distillation/extraction -- ISOSIV for separation of iso-paraffins from normals -- PSA for H 2 separation from Syn Gas -- Molex Process- for ext of n-paraffin for LAB prodn -- Parex Process- for ext of p-xylene for PX prodn  Supercritical extraction of Asphalts with propane  Introduction of Low Pressure Technologies

Energy Minimisation in Refinery  Furnace Flue Gas temp lowering either with APH or outside/inside mounted steam generator  Excess Air Control  Steam Generation in HP Furnaces General for Furnace Efficiency Improvement

Energy Minimisation in Refinery  Use of packinox to low approach Heat Exchangers  Cleaning of Heat Exchangers periodically  Better thermal design with optimum velocities General for Heat Exchanger Efficiency Improvement

Energy Minimisation in Refinery  Minimise Recirculation / Spillback flows  Operate at the best efficiency point to the extent possible  Better specification of pumps / compressors during design stage for operation around best efficiency point.  Pressure cascading to avoid successive pumping and compression. General Pumps & Compressors Efficiency Improvement

Energy Minimisation in Distillation

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