How OLI Has Been Used to Tackle the Nasty Problem of ......6 Problem Description Increasing Sour Water Stripper (SWS) off-gas production • Roughly 1/1/1 molar ratio NH 3 /H 2 S/H

How OLI Has Been Used

to Tackle the Nasty Problem

of Refinery Sour Water

– DART™

Steve Grise, Joe Flowers, Carlos Cavalca,

Steve Meyer, Zeru Tekie, Mateus Panosso

and Steve Puricelli - DuPont

October 16/17, 2012

DUPONT PUBLIC INFORMATION

Agenda

• Brief introduction to DuPont and Clean Technologies

• DARTTM Technology • Drivers – sustainability, economics and environment • DART™ concept • Key advantages of the process • Process description • Simulation results

• Sour Water

• What’s in Sour Water ? • Determining DART™ feed

DUPONT PUBLIC INFORMATION 2

FEEDING THE WORLD REDUCING OUR DEPENDENCE ON FOSSIL FUELS

KEEPING PEOPLE AND THE ENVIRONMENT SAFE

© National Geographic images

DuPont is applying our science to find solutions to some really BIG challenges…

WE ARE A MARKET-DRIVEN SCIENCE COMPANY


DuPont Clean Technologies

Alkylation

STRATCO® Technology and proprietary equipment for refiners to produce clean alkylate for blending into gasoline

Hydroprocessing Global Engineered

Solutions Air Pollution Control

IsoTherming™ Technology and proprietary equipment for refiners to hydrotreat middle petroleum distillates to reduce sulfur content and for the production of renewable fuels

GES Comprehensive products and technical services for sulfur management, sulfuric acid alkylation units and sulfuric acid plants

BELCO®

Dynawave®

Technology and proprietary equipment for scrubbing emissions of SOx, NOx and particulates

Technology, proprietary equipment, and catalysts for sulfur management, sulfuric acid production, and spent acid regeneration

A global leader in integrated Clean Air and Clean Fuel sustainability solutions through best-in-class technologies, equipment and service offerings to improve productivity,

reduce air emissions and produce cleaner fuels

Sulfuric Acid Technology


World Crude Demand and Quality

2000 to 2020

0.0

10.0

20.0

30.0

40.0

50.0

60.0

70.0

80.0

90.0

100.0

2000 2005 2010 2015 2020

Pro

du

cti

on

(M

BP

D)

Other

High TAN

Heavy Sour

Light Sour

Light sweet

Source – EIA Long Term Outlook, OPEC World Oil Outlook 2009

Crude Demand and Nitrogen Content Trends

1

10

100

1000

10000

10.00 20.00 30.00 40.00 50.00 60.00 70.00 80.00

crude API

N c

on

ten

t /

pp

m

6

Problem Description Increasing Sour Water Stripper (SWS) off-gas production

• Roughly 1/1/1 molar ratio NH3/H2S/H2O

• Gas contains some additional hydrocarbons

Sulfur has value

• H2S sent to Claus to be converted to Sulfur

• NH3 is problematic in Claus (salt formation and loss of capacity)

Solutions ?

• Separate NH3 from H2S

• Chevron WWT

• Haldor Topsoe ATS

• Other ?

• Optimize Claus operation with NH3 present

Can we recover the N value in the ammonia ?

• With H3PO4 ? With H2SO4 ?


7

Partial Pressure of NH3 versus NH3/H3PO4 Ratio


8

Partial Pressure of NH3 versus NH3/H2SO4 Ratio


9

Basic OLI Model (ESP)

Developed OLI model

• Major components – H2O, H2S, NH3, H2SO4

• Minor components – CO2, Hydrocarbons

• Methyl- and Ethyl- Mercaptan

• Standard sets of equilibrium reactions

Used ESP to develop concept and Patent

Straight forward task with OLI

Assume a “standard” SWS off-gas feed

• 1/1/1 molar ratio NH3/H2S/H2O @ about 185oF


10

Technology Description

Scrubber to

remove NH3

Includes cooler

to remove DHrxn

Stripper to

remove H2S

Neutralize

Feed acid to control pH; Water to

maintain balance


11

Preliminary Design Case

• Processing 30 TPD SWS ammonia yielding 284 STPD ammonium sulfate liquor product (41% w/w) nominally 42.5M tons per year 100% basis, 104M tons per year Commodity basis

• Ammonium Sulfate product specification (modeling results).

Final Product

H2O 59.0 wt%

(NH4)2SO4 41.0 wt%

pH 7.0

pp(H2S) 0.00004 ppm

pp(NH3) 326.1 ppm

pp(MMCPTN) 0.002 ppm

pp(EMCPTN) 0.00004 ppm

f.p. 1.5 deg C

NH3/SO4 2.00


Ammonium Sulfate Solubility

Commy nullamcor ilis exeros alit dolobor

percipsummy nonsed min henibh ex

exeros nullaore molesto.

Ammonium Sulfate Solubility in Water

0

10

20

30

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60

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-40 -20 0 20 40 60 80 100 120 140 160 180 200 220 240 260 280 300

Temperature (C)

(NH

4) 2

SO

4 (

wt

%)

Proposed final product


Lab Validation – Experiment 1

Lab scale stripping of synthetic stripper feed

• Synthetic scrubber effluent

• Strip batch-wise

• Validated model ability to predict stripping

13 DUPONT PUBLIC INFORMATION

Potential Technology Benefits • Sour Water Stripper (SWS) gas recovery of NH3 species

• Increased Claus SRU capacity and minimization of Claus process downstream problems

• Up to 3.75 tons additional sulfur processing capacity gain per ton of NH3 removed.

• Catalyst and equipment fouling with ammonium sulfate salt deposits minimized

• Reduced water feed to Claus; Total volumetric reduction in Claus feed by ~50%

• Elimination of SWS NH3 separation costs

• Elimination of NH3 incineration (incinerator OPEX, NOx & SO2 emissions associated with ammonia incineration)

• Production of Ammonium Sulfate Liquor Feedstock for Fertilizer or Blending Product.

• Refinery downstream integration (e.g. agrochemicals) converting a waste product into a commodity chemical

• Production of N-containing fertilizer mostly “uncoupled” from natural gas cost (e.g., versus urea production)

• Helps enabling expansion of markets for high N-crudes when coupled with DART technology.

• Sustainable solution conversion of N-waste into N-fertilizer providing environmental and operational benefits


15

Refinery

DART™ NH3-Scrubbing

Ammonium Sulfate Plant

SWS gas (H2S, NH3, H2O)

Scrubbed SWS gas to SRUs (H2S, H2O) Ammonium Sulfate Liquor

(or solids) to Merchant Market

Fresh + Waste Acid

DART™ - NH3 SWS Gas Scrubbing - Ammonium Sulfate Production On-Site Facility


16

What is the DART™ feed composition ?

• A “standard” SWS off-gas is 1/1/1 molar ratio NH3/H2S/H2O, plus CO2 and hydrocarbons, but WHICH hydrocarbons ?

• Hydrocarbons depend on refinery operations (hydrotreater, cracker, coker, etc…)

• What is the analysis of the SWS ?

• Refineries don’t really care

• Hazardous (deadly) gas stream

• How do we determine our feed composition so that we can design our DART™ plant ?


17

Sour Water Strippers (primer)

• There are generally two types:

• Single column

• Two column (Chevron WWT)

• Proprietary part of refinery

• Costly to operate and maintain

• High energy consumer

• Corrosion issues

• Don’t publish knowledge

• We need to simulate the SWS designs -- OLI DUPONT PUBLIC INFORMATION

18

What is the feed to the SWS ?

• “Sour Water systems have been described as garbage disposals or toilets of refineries.” Armstrong et al, Today’s Refinery, June 1996.

• Any or all of these classes of compounds could be present.

• Worked with partner to characterize their SW.


Class of

compoundExpected compounds ?

Alkyls

C3 - C8 ?

Branched isomers

Anything one might find in

gasoline !

Alcohols Unlikely

Ethers/Epoxides Unlikely

Carboxylic acids Unlikely

Aldehydes/KetonesMethyl Ethyl Ketone (somewhat

surprizing)

PhenolsPhenol

Cresol

Aromatics

Benzene

Toluene

Xylene

Ethyl Benzene

Polynuclear

Aromatics

Naphthalene

Decalin

Anthracene

SulfidesMethyl Mercaptan

Ethyl Mercaptan

Amines (exc NH3) Organic amines

Nitriles

HCN

Acetonitrile

Propionitrile

"C" Compounds

"S" Compounds

"N" Compounds

19

Beefing up the OLI database !

• Many of the compounds we found in the SW sample were not in the OLI database.

• Used data from Dortmund Database to calculate K(T)

• Built database of remaining compounds


20

Simulations of SWS’s

• Required to simulate performance and off-gas composition from both single column and two-column systems.

• Worked with partners to match simulation versus readily measureable variables (T, P, flow, duty)

• Off-gas composition not available !

• Results agreed very well for both systems.

• Assume the off-gas composition was close enough for MECS to prepare design and basic engineering package for DART™ pilot.


21

Summary

• Utilized the power of the OLI software to

• Develop DART™ process concept and Patent

• Validate versus lab experiment

• Build a database to include the myriad of hydrocarbons

• Develop simulations for single column and two column sour water strippers

• Design pilot facility

• Success will be defined by the operation of the pilot

• Looking forward to sharing the successful operating data at the 2014 OLI Simulation Conference !


Thank You !!


Documents

How OLI Has Been Used to Tackle the Nasty Problem of ......6 Problem Description Increasing Sour Water Stripper (SWS) off-gas production • Roughly 1/1/1 molar ratio NH 3 /H 2 S/H