INTENSIFICATION OF THE DADPM PROCESS INDUSTRIAL APPLICATION OF A CAPEC PI METHOD ANNE BENNEKER, A.G.J. VAN DER HAM, A.J. ZEEUW, B. DE WAELE, H. VAN DEN BERG

NOVEMBER 19TH 2014

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INTRODUCTION (1) DADPM PROCESS

Formation and isomerisation of

amines (FRI)

Neutralisation &First separation

(NFS)

DADPMwork up

Brinework up

DADPM

NaClWater

Aniline

HClFormaldehyde

NaOH

Aniline

Aniline

Aniline

Theoretical method Mathematical approach Modeling

Only applied on literature processes

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INTRODUCTION (2) CAPEC PI METHODOLOGY

Lutze, P., Woodley, J. & Gani, R., An Innovative Synthesis Methodology for Process Intensification 2011: DTU Chemical Engineering.

Apply PI methodology from CAPEC on an industrial scale, running process

To propose (an) improvement(s) on the production process of DADPM operated by Huntsman in the Netherlands

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INTRODUCTION (3) OBJECTIVES OF THIS PROJECT

A six-step workflow Several sub-algorithms and tools Knowledge base Model library

Phenomena based workflow New design

Unit-operation based workflow Existing process

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APPROACH OF INTENSIFICATION (1) CAPEC PI METHODOLOGY

Objective function & performance metric Constraints Logical, structural and operational

Identification and enhancement of tasks Modeling of PI options Quantitative selection of best option Based on objective function

APPROACH OF INTENSIFICATION (2) WORKFLOW

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Objective function:

Performance metric: Efficiency, energy consumption, operating costs, simplification, capital costs

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INTENSIFICATION OF THE DADPM PROCESS STEP 1: PROBLEM DEFINITION

min𝐹𝐹𝑜𝑜𝑏𝑏𝑏𝑏 = ��𝑐𝑐𝑅𝑅𝑎𝑎𝑎𝑎𝑀𝑀𝑎𝑎𝑎𝑎 ,𝑖𝑖�̇�𝑚𝑅𝑅𝑎𝑎𝑎𝑎𝑀𝑀𝑎𝑎𝑎𝑎 ,𝑖𝑖 + �𝑐𝑐𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒 ,𝑖𝑖𝐸𝐸𝑖𝑖̇ + �𝑐𝑐𝑠𝑠𝑜𝑜𝑠𝑠𝑠𝑠𝑒𝑒𝑒𝑒𝑎𝑎 ,𝑖𝑖𝑚𝑚𝑖𝑖̇ � /�̇�𝑚𝐷𝐷𝐷𝐷𝐷𝐷𝐷𝐷𝑀𝑀

Start of PI procedure

Objective function definition

Process and design scenario definition

Process and product specifications

Definition of performance metric

Definition of maturity of the

process

Translation into logical, structural and operational

constraints

Base case design available?

Step A2/B2

Calculation of objective function Knowledge and model base search Analysis of limitations and bottlenecks Mixture properties Reaction properties Operation windows

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STEP 2: ANALYSIS OF THE DADPM PROCESS (1) APPROACH

Base case available

Step A2

Mass and energy balances

Task and phenomena based

flowsheets

Identification of limtiations and

bottlenecks

Analysis of limitations and

bottlenecks

Linking of limitations and

bottlenecks outside unit operations

Step U2 or P3

Maturity of new design

Calculation of costs per section 96% material costs Material efficiency ≈ 100%

Several possible limitations Energy required for separations Large recycles in process

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STEP 2: ANALYSIS OF THE DADPM PROCESS (2) IDENTIFICATION OF LIMITATIONS AND BOTTLENECKS

94%

3% 1% 2%

FRI section

NFS section

MDA work-up

Brine work-up

0

5

10

15

20

25

30

35

40

Hot energy Cold energy

Ener

gy c

onsu

mpt

ion

(MW

) Brine work-up

MDA work-up

NFS section

FRI section

Formation and isomerisation of

amines (FRI)

Neutralisation &First separation

(NFS)

DADPMwork up

Brinework up

DADPM

NaClWater

Aniline

HClFormaldehyde

NaOH

Aniline

Aniline

Aniline

Brine work-up section has largest contribution to energy costs

First separation highly influences DADPM and brine work-up sections

NFS and brine to be intensified

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STEP 2: ANALYSIS OF THE DADPM PROCESS (3) IDENTIFICATION OF SECTIONS TO BE INTENSIFIED

96% 4%

Material costs (€/hr)

FRI section

NFS section

MDA work-up

Brine work-up

Heuristic design approach

Enhancement of equilibrium in separation

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INTENSIFICATION OF THE NFS SECTION (1) APPROACH

Process to be intensified

From isomerisation Organic layer to MDA work-up

Aqueous layer to brine work-up

Neutralization using NaOH Plain vessel

Aqueous layer

Organic layer

Neutralization using NaOH Rotating vessel

Aqueous layer

Organic layer

Neutralization using NaOH Packed vessel

Organic layer

Aqueous layer

Neutralization using NaOH

Pervaporation membrane

Organic layer

Aqueous layer

Worst case: salts evenly distributed in organic an aqueous layer Best case: salts in equilibrium distribution between organic and aqueous

layer

Two mass balances Calculation of costs for DADPM and brine work up section

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INTENSIFICATION OF THE NFS SECTION (2) RESULTS

First separation scenario Indexed costs

DADPM section Indexed costs brine section

Base case 100 100

Worst case intensification 95 106

Best case intensification 89 82

0

500

1000

1500

2000

2500

3000

0 200 400 600 800 1000 1200 1400

Time (min)

NaCl

in d

adpm

laye

r (pp

m)

90°C 95°C

Selection of PI equipment from knowledge base Number of process options: 1.2*106 A maximum of 2 PI options per task is selected

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INTENSIFICATION OF BRINE WORK-UP (1) STEP 3: APPROACH

Task Possible PI options

DADPM extraction Base case, agitated cell extractor, centrifugal extractor

Brine stripping Base case

MeOH removal Base case, heat-integrated distillation, adsorptive distillation

Organic/aqueous separation

Base case, centrifugal phase separator, packed vessel

Step U2

Collection of potential

PI equipment

Medium or mature process

Pre-screening of potential PI equipment

Identification of sub-problems

Step U3

Reduction of # options Logical & structural Heuristics

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INTENSIFICATION OF BRINE WORK-UP (2) STEP 4: GENERATION OF FEASIBLE FLOWSHEET OPTIONS

Step U4

Retrieval of a superstructure

Determination of the number of process option

Screening by logical constraints

Screening by structural

constraints

Step U5

Process models using Aspen and Excel 27 options in total

Cost and energy calculations Sensitivity analysis and optimization

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INTENSIFICATION OF BRINE WORK-UP (3) STEP 5 & 6: SCREENING OF OPTIONS

Split

Base case

Agitated cell extractor

SplitCentrifugal extractor Base case Split Heat integrated distillation

Adsorption distillation

Base case Split Centrifugal phase separator

Packed vessel

Base case

MDA extraction Brine recovery Methanol recovery Organic/Aqueous separation

Split

Split

Only methanol recovery and organics/aqueous separation are intensified

Small difference with base case design

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INTENSIFICATION OF BRINE WORK-UP (4) STEP 6: OPTIMIZATION

Extractor (base case)

Stripping column (base case)

Heat-integrated distillation

Packed equilibrium vessel

Brine feed

Aniline

Extracted DADPM

Steam

Brines MeOH

Organic layer

Aqueous layer

Different level of modeling Errors and sensitivity

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INTENSIFICATION OF BRINE WORK-UP (5) RESULTS

Feed to brine section Indexed energy costs in brine work

Intensified brine Base case brine

1 Base case 95 100

2 Worst case scenario 100 106

3 Best case scenario 76 82

Intensification of first separation and brine work-up First separation reduces energy costs for DADPM (11%) and brine work

up (18%) Brine work-up intensification reduces costs by 5%

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INTENSIFICATION OF THE DADPM PROCESS RESULTS

Result of first separation

Indexed energy costs in brine work up Indexed energy costs

in DADPM work-up Intensified brine Base case brine

1 Base case 95 100 350

2 Worst case scenario 100 106 95

3 Best case scenario 76 82 89

Integrated way of PI on a complete process Systematic

Selection of the objective function is crucial for the success Large influence of user-input on the results of PI Focus on process tasks instead of unit-operations

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REVIEW ON CAPEC METHODOLOGY

Short-cut analysis before problem definition step Check if the unit equipment is operating at design specifications Reduce dependence on user-input A uniform, up-to-date knowledge base should be used Automate different sub-algorithms

All process models should be at the same level of detail An error analysis on the final process should be added Test sensitivity of the best options

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REVIEW ON CAPEC METHODOLOGY RECOMMENDATIONS

QUESTIONS AND DISCUSSION

THIS RESEARCH IS CURRENTLY UNDER REVIEW FOR PUBLICATION IN:

COMPUTERS AND CHEMICAL ENGINEERING JOURNAL