PROCESS FLOW DIAGRAM POLYETHYLENE

1 PROCESS FLOW DIAGRAM : POLYETHYLENE By: Cameron Shaw Daniel Couto Daniel LeClair Leigh Bedford Nicole Rich-Portelli Compressor: initial compression of ethylene feed to 1500 bar Hyper-compressor: compensates for pressure loss in recycle stream and outlet feeds to restore reactor inlet pressure to 2000 bar Reactor: Plug Flow Reactor (PFR) inside a cooling jacket T = 70C, P = 2000bar Separator: main source of pressure loss polymer solids fall to bottom and are sent to extruder unreacted ethylene recycled back to reactor PROCESS Overview PROCESS OVERVIEW Major safety concerns are around the plug flow reactor: Free radical polymerization of ethylene to POLYETHYLENE is a highly exothermic reaction Converts gaseous ethylene into viscous POLYETHYLENE melt Thus many constraints must be taken for a PROCESS that aims to be effective and safe.

2 Reactor temperature (prevent unideal and dangerous temperatures) reactor pressure (prevent pressure increases and decreases in reactor) flow rate in reactor (prevent unideal flow rates) HAZOP HAZOP LOW TEMPERATURE HAZOP HIGH TEMPERATURE HAZOP LOW PRESSURE HAZOP HIGH PRESSURE HAZOP LOW FLOW HAZOP HIGH FLOW HAZOP REVERSE FLOW HAZOP - FINAL CHEM ENG 4N04 SDL Project - The Production of Formalin from Methanol Group B4 Matt Galachiuk - 0752265 Kyle Kovacs - 0849889 Sana Shamsher - 0456846 Angela Zeinstra 0842631 Honorable Mention: Jervis Pereira PROCESS Overview and Principles Reaction Kinetics and Principles CH OH + O2 CH O + H O H RXN = -156 kJ/mol CH OH CH O + H H RXN = kJ/mol Operating temperature: 900 to 950K - resulting selectivity?

3 - resulting conversion? Operating pressure: atmospheric Catalyst: silver Figure: G. A. Bowmaker, G. I. N. Waterhouse, J. B. Metson. Mechanism and active sites for the partial oxidation of methanol to formaldehyde over an electrolytic silver catalyst. Applied Catalysis A: General, vol. 265, no. 1, , June 2004. Catalyst Regeneration Frequency of replacement: every 3 years Frequency of regeneration: every years PROCESS to regenerate catalyst: flood with cesium salt solution - catalyst remains in reactor Volume of catalyst needed: 2 m3 - based on mass balances and a linearly deactivating catalyst Mass of catalyst needed: 21 000 kg - based on a density of 10 490 kg/ m3 Production Losses Two shut downs in a 3 year period (lifetime of catalyst) Shutdowns last for 1-2 weeks each 1st shutdown: full maintenance, catalyst regeneration 2nd shutdown.

4 Full maintenance, catalyst replacement ITEM FREQUENCY COST Lost production Twice in 3 years $ 400 000 Maintenance Twice in 3 years $ 160 000 Replacing catalyst Once in 3 years $ 10 000 000 Regeneration Once in 3 years negligible TOTAL $ 11 120 000 Class Activity HAZOP Analysis Guide Word Deviation Causes Consequences Existing Protection Recommendations High Level in separator is too high Low Level in separator is too low None There is no liquid in the separator Class Activity HAZOP Analysis Janine HoJannanySrichandraClaudia ChanKushlaniWijesekeraChris PaslawskiNovember 22, 2012[ DIAGRAM provided by the Burlington Water Purification Plant][Simplified from P&IDs provided by the Burlington Water Purification Plant]Overall Scope Flocculation and Sedimentation[Simplified from P&IDs provided by the Burlington Water Purification Plant]Recycled microsandRaw water from low lift Sludge to waste treatmentSulfuric AcidAlumPolymerFresh microsandTo ozone contactorDrainDrainDrainDrainOzone ContactorsOzone recycleSodium BisulphiteHydrogen PeroxideSettled water(From Settling tanks)To FilterOzone[Simplified from P&IDs provided by the Burlington Water Purification Plant]Ozone ContactingOzone QuenchingTo Ozone DestructorsOperability: Requirements: 90% of 113ML reservoir capacity Water Quality constraints set by Ministry of Environment of Ontario: Turbidity pH Fluoride ion concentration Colour Ozone Mircoorganisms.

5 Crypto, Giarda, CholiformBacteriaOperating [NTU]Output Flow rate [ML/day] of Fluoride [mg/L]Output Flow Rate [ML/day]Operating Window -[Fluoride]Reliability Reliability = Probability of failure = Availability = Back-Up Equipment Ozone contactors (4 total, 2 currently in use) 3 Pairs each of low and high-lift pumps (55, 75, 97 ML/day) By-pass valve for raw water Diesel-run generator in case of power outage Safety and Control Operation is controlled by the SCADA (Supervisory Control and Data Acquisition) system: Centralized monitoring and control for multiple inputs and outputs. Collects field data, transfers this data to a central computer through controllers (eg. PLC), and then displays information to the operator on a screen. P&ID for Settling SectionpHRecycled microsandRaw water from low lift Sludge to waste treatmentPolymerFresh microsandTo ozone contactorDrainDrainDrainDrainLSHHTurbSan dpHRecycled microsandRaw water from low lift Sludge to waste treatmentPolymerFresh microsandTo ozone contactorDrainDrainDrainDrainLSHHTurbLCL AHFOR ecycle StreampHRecycled microsandRaw water from low lift Sludge to waste treatmentPolymerFresh microsandTo ozone contactorDrainDrainDrainDrainLSHHTurbLCL AHFOTurbTurbC