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:

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

CH₃OH + ½O2 → CH₂O + H₂O ΔH RXN = -156 kJ/mol CH₃OH → CH₂O + H₂ ΔH RXN = 85.0 kJ/mol

Operating temperature: 900 to 950K - resulting selectivity? - 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, pp.85-101, June 2004.

Catalyst Regeneration

Frequency of replacement: every 3 years Frequency of regeneration: every 1.5 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: 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 HoJannany Srichandra

Claudia ChanKushlani Wijesekera

Chris Paslawski

November 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

microsand

Raw water

from low lift

Sludge to waste treatment

Sulfuric

Acid

Alum

Polymer

Fresh microsand

To ozone contactor

DrainDrain

Drain

Drain

Ozone Contactors

Ozone recycle

Sodium

BisulphiteHydrogen Peroxide

Settled water

(From Settling

tanks) To Filter

Ozone

[Simplified from P&IDs provided by the Burlington Water Purification Plant]

Ozone Contacting

Ozone Quenching

To Ozone Destructors

Operability: Requirements:

90% of 113ML reservoir capacity

Water Quality constraints set by Ministry of Environment of Ontario:

Turbidity

pH

Fluoride ion concentration

Colour

Ozone

Mircoorganisms: Crypto, Giarda, Choliform Bacteria

Operating Window-Turbidity

0

0.05

0.1

0.15

0.2

0.25

0.3

0.35

0 50 100 150 200

Tu

rbid

ity

[NT

U]

Output Flow rate [ML/day]

0

0.2

0.4

0.6

0.8

1

0 50 100 150 200

Co

nce

ntr

ati

on

of

Flu

ori

de

[m

g/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 Section

pH

Recycled

microsand

Raw water

from low lift

Sludge to waste treatment

Polymer

Fresh microsand

To ozone contactor

DrainDrain

Drain

Drain

LSHH

Turb

Sand

pH

Recycled

microsand

Raw water

from low lift

Sludge to waste treatment

Polymer

Fresh

microsand

To ozone contactor

DrainDrain

Drain

Drain

LSHH

Turb

LC

LAH

FO

Recycle Stream

pH

Recycled

microsand

Raw water

from low lift

Sludge to waste treatment

Polymer

Fresh

microsand

To ozone contactor

DrainDrain

Drain

Drain

LSHH

Turb

LC

LAH

FO

Turb

Turb C