Process Simulation of Solvent Deasphalting Plants With PROII

EDL Anlagenbau Gesellschaft mbH

Moscow, 28-30 March 2012

EDL Anlagenbau Gesellschaft mbH

Process Simulation of Solvent Deasphalting Plants

with PRO/II based on Thermodynamic Equilibrium Data

"VLE K -Values - Fill Options"

EDL Anlagenbau 2EDL_SDA_PRO/II_Fill-Options

Introduction

SDA, the Solvent Deasphalting technology is actually one of the

most interesting „Bottom to Barrel“ technology for heavy residues

in modern refineries

? • Large price differences between light sweet crudes and heavy sour crudes

created strong incentives for bottom processing tecchnologies

• Old fashion technology SDA in the lube oil refinery

will be more and more also applied in fuel oil refineries, too

• The SDA technology is the lowest investment cost variant compared to

Gasification, Visbreaker, Hydrocracker, Coker et al

• In the best case both products DAO as well as Pitch can be converted in

further process steps to valuble products, no further residues will be available


Integration of SDA in modern Refinery

VDU AR

Crude

SDA

ADU

VR

Bitumen plant

Asphalt (Pitch)

Bright Stock

FCC -Plant

Hydrocracker

Lube Oil Refinery

Fuel Oil Refinery

DAO

ADU…Atmospheric Distillation Unit

VDU…Vacuum Distillation Unit

SDA…Solvent Deasphalting

AR…..Atmospheric Residue

VR…..Vacuum Residue


Typical SDA

a typical SDA plant is a PDA, e.g.

- Propane Deasphalting Plant -

The plant normally consists of the following parts:

• Propane Extraction

• DAO Train

• Asphalt Train

• Propane Condensation and Recovery

• Pressure Relieve -, Slop - and Flushing system


SDA simulation and design

The simulation and design of a SDA , especially the

liquid –liqud extraction process is a challenging task !

? • the feed, Vacuum Residue can only be simulated with pseudo

components e.g. it is impossible to use components from the data base

with a defined structure

• the pseudo components have no structure to produce BIPs from the

UNIFAC –Model to build activity coefficients between the components

• the liquid –liquid extraction process for the SDA is based on the different

solubilities between the solvent and the hydrocarbons

• BIPs are necessary to calculate the equilibria in the two liquid phases,

the DAO and the Asphalt phase

BIP… Binary Interaction Parameters


Model Basis: „Chueh and Prausnitz“

The BIPs can be calculated based on a publication from Chueh and Prausnitz

(1967) for an EOS (Equation of State) via the partial molar volumes of the

multicomponent liquid mixture:

)(5.0 bT

a

b

RTP

Equation of State:

Partial differentiation of EOS:

with the mixing rules for a mixture and used for

),,,,,,(........,,,, biaiciciciiiijiii TPxfababa

222/12

2/1

)(

2

)(

)(

)/()(2

)1(

b

b

T

a

b

RT

Tb

babax

b

b

b

RT i

kkii

k

k

0)( and 0)(

2

2

cc TT

PP

0867.0 and 4278.0a b


applying the pseudocritical rules to the critical region: 93,0RT

)()(

)()(

'

'

RCMCTCMCM

RCMCTCMCM

TD

TDTTTT

Further, with adjustments to SRK and PR applied in PRO/II we get

the BIP„s between the components:

n

CMjCMi

CMjCMi

ijk

2/)(1

3/1'3/1'

3/1'3/1'

3n (the best fit with experimental data)

Model Basis: „Chueh and Prausnitz“


Notation

factor ..acentric..........

EOS KwongRedlich in parameter essdimensionl....,

phase liquidin ffraction ....molex.........

mixture of volumecritical true.........

mixture of volumeicalpseudocrit corrected.......

mixture of volumeicalpseudocrit........

phase liquidin k component of memolar volu partial..........

mixture liquidor liquid of lume..molar vo..........

mixture liquid of volume..totalV.........

re temperatureduced..........T

ure..temperatT.........

pressure ..totalP.........

parametersn interactiofor sBIP'.........k

region critical theofunction t correction)...D(T

EOS KwongRedlich in nstantsb.......coa,

a

CT

'

CM

R

ij

R

b

CM

k


PRO/II PFD- one stage

Typical one stage liquid –liquid extraction unit:


Pseudo component feed Vacuum Residue (VR)

kg/kg 9669.015 d


Pseudo component properties


PRO/II- K-value –Fill Options


EOS for „Fill –Options“

The following EOS are awailable for the „Fill –Option“:

- Modified Chueh Prausnitz Hydrocarbon Fill -

• Soave Redlich Kwong

• SRK –Panagiotopoulos-Reid

• SRK –Modified Panagiotopoulos-Reid

• SRK –SIMSCI

• Peng –Robinson

• PR –Panagiotopoulos-Reid

• PR –Modified Panagiotopoulos-Reid

• Predictive Peng Robinson 78

• Tacite

The best fit with practical results we achieved with the

SRK –Modified Panagiotopoulos Reid thermodynamic !


BIPs calculation

BIPs calculated from the output report:


Stream list

DAO: 28.5 %, Asphalt : 71.5 %


VR-DAO-Asphalt TBP


VR-DAO-Asphalt distribution


Property list

As shown in the property list special data as S, V, Ni, Fe, N and CCR

can be controlled in the DAO, Asphalt via a distribution in the feed (VR):


Bench scale tests

The theoretical results were compared to bench scale tests in a autoclave:

Conditions: subcritical pressure from 30 to 35 bar and

temperature about 50°C

Solvent: Propane (100%)

Autoclave


Bench scale tests

Results: DAO and Asphalt from the bench scale unit

DAO…..Deasphalted oil

AS……..Asphalt (Pitch)

Asphalt DAO

*…SRK -Mod Panag. -Reid

**…PR -Mod Panag. -Reid

The SRK Modified Panagiotopoulos -Reid method gives the best fit to the practical results !


Study of thermodynamic models


Solvent impact

The choise of the solvent or solvent mixture is very important !

Asphaltenes

Resins

Oils

Cru

de

Oil

Am

os

ph

eri

c R

es

idu

e

Va

cu

um

Res

idu

e

Pro

pa

ne

Pre

cip

ita

te

Pe

nta

ne P

rec

ipit

ate

Hep

tan

e P

rec

ipit

ate


Simulation studies of Solvent mixtures


Ternary plots -Temperature influence-

Ternary plot from literature:

1 2

3

Solvent to Feed ratio

(tie lines):

1…0,5

2…3,0

3…8,0

Binodal curves


Ternary plot – Pressure influence -

Binodal curves

Solvent to Feed ratio

(tie lines):

1…0,5

2…3,0

3…8,0

1 2

3


PRO/II simulation of multiple stage extraction

Heater on stage 1 to precipitate Asphalt

Controller for precipitation


Ternary plot – Pressure influence -

The number of trays are not so important !

For the design the

HTU, NTU concept

must be applied !

HTU…Height of Transfer Unit

NTU…Number of Transfer Unit


The Solvent Deasphalting (SDA) is a key technology processing heavy

residues to valuable oils (DAO, Deasphalted Oil) and asphalt (Pitch) for the

Bitumen production. The process will be more and more interesting also in

fuel oil refineries as a “Bottom to Barrel” technology with low costs.

The calculation of the extraction process with NPB components is difficult

because of the lack of BIPs between the components. Other ways to build

up the data from the UNIFAC model are not applicable.

The model from CHUEH and PAUSNITZ, published in the AIChE Houston

Meeting in 1967 is applicable to estimate the BIPs between the NBP

components and the solvents, finally to calculate the extraction of the SDA

for high pressure.

Summary


Summary

The model application in the PRO/II simulation program under the

Equation of State (EOS) with the VLE K values –“Fill Option” is the basis

for the complete process simulation of the whole SDA process.

Experimental results have shown that the model can be applied to design

the SDA process with different solvents (Propane, Butane etc.) and

solvent mixtures for the sub- and supercritical extraction processes.

Further investigation should be done to apply the model also to other

extraction technologies e.g. solvent extraction with furfural or NMP.

Thank you for your attention !

Process Simulation of Solvent Deasphalting Plants With PROII

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