process sustainability

7/30/2019 Process sustainability

1/27

DESIGN, COSTING & SUSTAINABILITY

ENG 3129/3130/3131/3132

Lecturer: Dr Lauren Basson

Centre for Environmental Strategy (CES)

Faculty of Engineering and Physical Sciences (FEPS)

PART 2: SUSTAINABILITY


2/27

Outline

- Clean Technology:

the pollution avoidance approach

- Process Design for Sustainability

- Strategies to Improve Process Designs


3/27

What is a clean technology?


4/27

A clean technology is

a means ofproviding a human benefit

which, overall, usesless resources

and causes less environmental damage

than alternative means with which it is

economically competitive.

Roland Clift

Clean Technology


5/27


6/27

Process Design for Sustainability

How do we go about designingchemical processes?


7/27

Process Design

General approach Initial generation of a large number of designs at a low level of

detail

Screening of these to smaller number

Consideration of these at a more detailed level

Selection of a particular design Final development of this design to a level that enables

construction to commence

Screening/selection to meet design objectives, such as

product quality profitability

environmental performance

safety

etc.


8/27

Criterion 1

Criterion2

DiscreteAlternatives

Estimated

ValueEstimatedRange

Decision Spaces During Design Development


9/27

Operating

RegimeUncertainty

Discrete

Feasible Regions

Criterion2

Criterion 1



10/27

Operating

RegimeUncertainty

Discrete

Feasible Regions

Criterion2

Criterion 1



11/27


12/27

EXPLANATORY NOTES

Economic Cost means the cost of delivering theproduct or service; i.e. conventional cost (capital plusoperating), not including external costs.

Environmental Impact corresponds to one categoryamong several, and must be evaluated for the

complete supply chain or life cycle.

Decision frontier is actually multi-dimensional.Techniques like process modelling can be used to

construct the surface.


13/27

COST

-8 -6 -4 -2 0 2 4 6 8

First Principal Component

-1.0 -0.5 0.0 0.5 1.0

-8

-6

-4

-2

0

2

4

6

8

Secon

dPrincipalCompo

nent

-1.0

-0.5

0.0

0.5

1.0

44%

WS

JOBS SS

CC

ALF

FFETA&E

CCNG

WATER

PFDesign Scenarios

FBC

Design Scenarios

First Principal Component

Second

PrincipalComponent

Technology Selection for Coal Based Power Generation

Basson 2004


14/27

Strategies to Improve Process Designs


15/27

The Waste Management Hierarchy


16/27


Allen, D.T and K.S Rosselot (1997). Pollution Prevention for Chemical Processes. John Wiles and Sons, New York


17/27


Ammonia & Bioethanol & VCM

Chlorinated Methanes & Gas Oil Hydrofining

Claus Sulphur & Hydrogen Cyanide &

Oligomerisation of LPG


18/27


Reduction


modify reactor

different feed/process


19/27


Reuse


direct material or energy recovery


20/27


Recycling/Energy Recovery

Elsewhere in process

Additional processing to enable material or energy recovery


21/27





22/27




includes industrial symbiosis via direct use or processing


23/27




24/27




25/27

Spent Fluoridic

Caustic (SFC)Water

Alkylation

Process

ASO washvessel

HFcatalyst

50wt%NaOH

ASO

(fuel oil)

4.5wt%NaOH

Spentfluoridic

caustic fromrelief system

Acidre-runcolumnStripping

isobutane

Acid +

impurities

Recoveredacid

Impurities +acid losses

Spentfluoridiccaustic


26/27


27/27

For Next Week

In your groups, prepare a draft presentation describing the processyou have designed.

Include

- Goal of process

- Flow sheet (simplified and accessible if necessary)- Highlight key features of mass and energy balance

- Rationale for design choices

- Some initial thoughts on key environmental impacts

- Some initial thoughts on areas for improvement

Upload your draft presentation on the Ulearn site submission boxwill be available

Deadline: Thursday 10 March 17h00

process sustainability

Documents