PIL: The experts in process improvement technologies Recent Experiences in Applying Process Integration Techniques to Oil Refineries Dr. Steve Hall Tel: +44 161 918 6789 Mob: +44 7534 721862 steve.hall@processint.com www.processint.com w w w .processint.com + 4 4 1 6 1 9 1 8 6 7 8 9 One Central Park, Northam pton Road, Manchester, M4 0 5 BP, UK
This Presentation: • Process Integration Limited • A Personal Perspective PIL: The experts in process improvement technologies • Typical PI Refinery Projects • Consider 2 Refinery Case studies • Hydrogen management in a modern refinery • HEN retrofit including anti-fouling equipment • Summary Slide Num ber: 2
Process Integration Ltd - a spin-out company from Manchester University’s PIL: The experts in process improvement technologies ‘Centre for Process Integration’ PIL provides: Software, Training, Consultancy to its clients PIL uses Advanced Process Improvement Technologies Slide Num ber: 3
Personal Perspective: • Comparing 2013 with 1992, major steps forward: • Marriage of graphical/insight and mathematical approaches PIL: The experts in process improvement technologies • Decomposition approaches • Improved link between process integration and simulation tools PI MIN LP Slide Num ber: 4
Personal Perspective: Today’s Capabilities • Today’s tools are more in-line with how chemical/process engineers work PIL: The experts in process improvement technologies • Specific important areas of application • Operational optimisation • Control of retrofit projects (still some way to go though) Slide Num ber: 5
Typical PI Refinery Projects • Energy savings • Operational optimisation – process units PIL: The experts in process improvement technologies • Operational optimisation – utility units • Hydrogen management • Water minimisation Slide Num ber: 6
Typical PI Refinery Projects • Energy savings • Operational optimisation – process units PIL: The experts in process improvement technologies • Operational optimisation – utility units • Hydrogen management • Water minimisation • = This presentation Slide Num ber: 7
Consider 2 Case Studies: • Demonstrate the practical application of new process integration technologies PIL: The experts in process improvement technologies • Case Study 1: Hydrogen management • Shows new techniques with practical modifications • Case Study 2: HEN retrofit techniques used in Crude Unit Revamp • Shows both new and old techniques in action Slide Num ber: 8
Case Study 1: Introduction • Case Study 1: Applying hydrogen pinch techniques to whole refinery PIL: The experts in process improvement technologies • Sinopec refinery: • Crude 13.5 MTPA, Ethylene 1 MTPA • Two objectives • Operational optimisation (no investment) • Revamping (with investment) • Project shows both new and modified hydrogen integration techniques Acknowledgement: LPEC Slide Num ber: 9
Case Study 1: Hydrogen Distribution System SR steam reformer SR Import CCR PIL: The experts in process improvement technologies CCR catalytic reformer HCU hydrocracker HCU DHT KHT DHT diesel hydrotreater KHT kerosene CNHT NHT hydrotreater CNHT cracked naphta hydrotreater HDA NHT naphta hydrotreater Fuel HDA hydrodealkylation Slide Num ber: 1 0
Case Study 1: Challenges Facing Refineries Gasoline & Diesel Regulations Lower sulphur – more hydrotreating PIL: The experts in process improvement technologies Lower benzene – less reforming Lower aromatics More hydrogen used, less hydrogen generated Greater demands on hydrogen system Slide Num ber: 1 1
Case Study 1: Targeting Minimum Hydrogen This is a Process Integration Conference: PIL: The experts in process improvement technologies Let’s do some targeting ! Target minimum hydrogen consumption… Slide Num ber: 1 2
Case Study 1: Targeting Minimum Hydrogen Step 1: Identify sources and sinks of hydrogen: PIL: The experts in process improvement technologies Simplified diagram of consumer Recycle (R) Make-up (M) Purge (P) Source Sink Separator Liquid feed Reactor Liquid product Slide Num ber: 1 3
Case Study 1: Targeting Minimum Hydrogen Step 2: Draw hydrogen purities/flow plot: 1 PIL: The experts in process improvement technologies 0.9 0.8 0.7 0.6 Purity (-) 0.5 0.4 0.3 0.2 0.1 0 0 50 100 150 200 250 300 Flowrate (MMscfd) Slide Num ber: 1 4
Case Study 1: Targeting Minimum Hydrogen Step 3: Draw purity vs hydrogen surplus diagram PIL: The experts in process improvement technologies 1 1 0.9 0.9 + _ 0.8 0.8 0.7 0.7 0.6 0.6 Purity (-) Purity (-) 0.5 0.5 0.4 0.4 0.3 0.3 0.2 0.2 0.1 0.1 0 0 0 10 20 30 40 50 0 50 100 150 200 250 300 Hydrogen surplus (MMscfd) Flowrate (MMscfd) Actual Hydrogen Surplus Slide Num ber: 1 5
Case Study 1: Targeting Minimum Hydrogen Target minimum hydrogen flow: 1 PIL: The experts in process improvement technologies 0.9 0.8 0.7 0.6 Purity (-) Hydrogen 0.5 Pinch 0.4 0.3 0.2 0.1 0 0 10 20 30 40 50 Hydrogen surplus (MMscfd) Slide Num ber: 1 6
Case Study 1: Using the pinch curves How should we exploit purification units (pressure swing adsorption, membranes)? PIL: The experts in process improvement technologies 1 Possible Benefit 0.9 0.8 0.7 Certain Benefit 0.6 Purifier No Benefit 0.5 0.4 0.3 0.2 0.1 0 0 2 6 8 10 12 4 Hydrogen surplus / MMscfd Slide Num ber: 1 7
Case Study 1: Hydrogen Pinch Analysis This provides us with an “ultimate” target, but ignores : PIL: The experts in process improvement technologies • pressure constraints • compressor requirements • piping requirements • practical constraints • network complexity • impurities (lumped as CH 4 ) Slide Num ber: 1 8
Case Study 1: We need to consider the impurities Use MINLP to model other factors Combine graphical and mathematical techniques to produce practical retrofit designs Include constraints, e.g. PIL: The experts in process improvement technologies H2/Oil ratio entering reactor ≥ lower bound H2 partial pressure in the gas mixture (makeup hydrogen + recycle) ≥ lower bound Recycle Makeup hydrogen Reactor Liquid Slide Num ber: 1 9
Case Study 1: Modified Hydrogen Network Optimisation PIL: The experts in process improvement technologies Slide Num ber: 2 0
Case Study 1: Hydrogen technology Enabled in Software PIL: The experts in process improvement technologies Embedded physical properties models improve accuracy Slide Num ber: 2 1
Case Study 1: Base Case Network A basic design from the feasibility study of de-bottlenecking project PIL: The experts in process improvement technologies 1.2 MPa main 2.4 MPa main 4.5 MPa main Slide Num ber: 2 2
Case Study 1: Hydrogen Pinch Diagram H 2 Purity PIL: The experts in process improvement technologies H 2 Surplus Hydrogen supply very close to target Increase Based on the current hydrogen purifying strategy purification BUT, over 25000 Nm3/h pure hydrogen is lost Slide Num ber: 2 3
Case Study 1: Optimisation Objective: minimise total operating cost (TOC) TOC = H 2 generation + compression - Fuel gas value Fuel gas = H 2 from providers – Net H 2 used by consumers PIL: The experts in process improvement technologies H 2 consumption in each consumer is assumed to be fixed Value of fuel gas based on net heating value H 2 /Oil ratio and H 2 partial pressure in each hydro-processor cannot be decreased Other constraints Keep certain parts of the hydrogen network as they are in the existing network (guided by plant engineers) Priority given to recovering hydrogen in purges from various hydrogen consumers Slide Num ber: 2 4
Case Study 1: Optimisation Scenario 1 No new purification unit PIL: The experts in process improvement technologies # 4 HTU is changed from once-through to complete recycle Higher compression duty Lower total hydrogen supply Total operating cost reduced by 3.45 MM$/yr. No investment Slide Num ber: 2 5
Case Study 1: Optimisation Scenario 2 New PSA + existing membrane PIL: The experts in process improvement technologies Optimised new PSA capacity: around 10000 Nm 3 /h Total hydrogen supply can be reduced by 14500 Nm3/h Capital cost estimated: 4.9 MM$/yr Total operating cost reduced by 10.1 MM$/yr Simple payback = 0.5 yrs Slide Num ber: 2 6
Case Study 1: Optimisation Scenario 3 Larger PSA + turn off existing membrane PIL: The experts in process improvement technologies Optimised new PSA capacity: around 16000 Nm 3 /h Total hydrogen supply can be reduced by 14627 Nm3/h Capital cost estimated: 7.0 MM$/yr Total operating cost reduced by 10.2 MM$/yr Simple payback = 0.7 yrs Slide Num ber: 2 7
Recommend
More recommend
