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Novel Approach to Ammonia Plant Revamps with ZoneFlow™ Reactor Technology

SANJIV RATAN & Michael Ralston

ZoneFlow Reactor Technologies, LLC (ZFRT), USA Prof. Juray de Wilde,

Universite Catholique De Louvain (UCL), Belgium

ZoneFlowTM Reactor Technologies, LLC

Presentation Outline

Introduction Steam Reforming “pellet” catalyst - Status quo ZoneFlowTM (ZF) Reactor Technology - an innovative

breakthrough ZF development status and validation programs Application of ZF Reactor Technology in ammonia plants

• ZF Single-Pass Reactors (ZF-SP)• ZF Convective Pre-Reforming Reactors (ZF-CPR)• ZF for Post Reforming (ZF-PR)

Confidential information of ZONEFLOW REACTOR TECHNOLOGIES, LLC 2

Introduction

Projected global growth for nitrogen fertilizers: 2% per year

Ammonia plant revamp / expansion is the potential driver

Expansion often constrained by primary reformer / SMR (dP, TSM, firing)

Proven solutions in place for typical 20-30% additional capacity but often constrained by existing SMR (mainly catalyst ) limitations


Ammonia Plant Syngas Generation Front-end


Steam Reforming Pellet Catalyst - Status Quo

Inherent deficiencies of the conventional "pellet" steam reforming catalyst, limiting reformer capacity increase: • high pressure drop• catalyst attrition / breakage from thermal cycling• limited heat transfer and associated higher tube

temperatures• flow / temperature non-uniformity due to random packing• very low catalyst effectiveness


ZoneFlow Reactor Technology– an Innovative Breakthrough

Advanced high-performance structured catalyst Step improvement of key performance

parameters • up to 2 times higher heat transfer (along with internal radiative transfer)• up to 70% lower pressure drop• up to 10 times higher catalyst effectiveness• high strength metal substrate; longer stable life• annular flexible casing; near-wall flow jets• adaptive structure for Convective pre-reforming


from random packing to engineered foil structure; also non-acidic and steam stable

from strength-limited voidage of ~ 50 % to ~ 90% voidage with robust substrate

from limited surface (GSA) enhancement to high GSA fin structure

Conventional SMR Catalyst v/s ZF Reactors


ZF offers step reduction in dP combined with multifold increase in heat transfer

ZoneFlowTM

structuredCatalyst

Conventional pellet

catalyst

Conventional SMR Catalyst v/s ZF Reactors


ZoneFlowTM

structuredCatalyst

Conventional pellet

catalyst Increased catalyst effectiveness ; higher

resistance to coking and upsets ; longer life

from random packing tube wall contact to flexible casing for uniform proximity to wall

from limited crush strength against thermal cycling to durable metal substrate

from diffusion-limited active site access to micro-layered full surface access

No attrition from thermal cycling; stable dPand flow uniformity over full operating life

ZF CFD Modeling (dP and Heat Transfer)


0%

50%

100%

150%

200%

250%

0% 50% 100% 150% 200%

Relative ΔP

New SMRs

Revamps

1.E-03

1.E-02

1.E-01

1.E+00

1.E+01

1.E+02

5.E+01 5.E+02 5.E+03 5.E+04 5.E+05 5.E+06

hf /

dP/

dz

dP/dz

Empty tube

Different ZF Casing Designs

Relat

ive H

eat T

rans

fer

Coef

ficien

t

ZF Kinetic Modeling and FEA Analysis


ZF Commercial Demonstration


Installation Operation

Extraction

Demonstrated Results Compared to Pellet Tubes

80o C lower TMT 24% lower pressure drop No hot spots ZF operation >15,000 hrs with several thermal cycles

Lower S/C ratio operation was not available


Presenter

Presentation Notes

The Commercial Tests far exceeded our expectations. I have listed the key parameters here with the demonstrated results. The key results which are most note worthy are: TMT was significantly lower in the ZoneFlow filled tubes, 80° C at start-up. The reactors have achieved long term operation objectives and remain in commercial operation with over 15000 hours. Most operating companies we discussed longevity testing with consider 2000 hours a validation target. 0:53

ZFRT Pilot Plant

At Materials and Process Engineering (IMAP) Division in Université catholique de Louvain (UCL), Belgium

Facilities and campaigns for extensive testing of ZF reactorsunder various commercial conditions and beyond

In collaboration with Professor Gilbert Froment Operational 2Q 2018


ZFRT Pilot Plant Installation


Ammonia Plant Revamps

Revamp approaches• ZF-SP reactors replacing pellets to allow capacity increase

without added dP or increase in tube temperatures

• Adding ZF-CPR Reactors in primary reformer convection zone to utilize high grade convective heat for producing additional hydrogen instead of steam

• Use of ZF-PR reactors in post-reformers or heat-exchange reformers for step capacity increase , which are inherently heat-transfer limited and capital intensive


Typical Reforming Section of a Ammonia plant


500-550 oC

780-820 oC

10-13% CH40.3-0.5% CH4

450-500 oC

950-1000 oC H2/N2 vol. ratio ~3

ZF-SP Reactors for Stressed SMRs

Stressed SMR Indicators / Attributes • Pressure drop (and build up) limiting throughput• Loss of catalyst activity and related heat transfer or

Shorter EOR activity• Hotter tubes / Hot spots • Carbon formation at inlet • Catalyst bridging / settling from thermal cycling• Shorter (remaining) tube life

Replacing (pellet) catalyst in these SMRs with ZF-SP Reactors can overcome these deficiencies


ZF-SP for De-Stressing of SMR


SMR De-Stressing SMR Design

Stressed Operation

ZF-SP replacing pellets

Relative Capacity, % 100 95 100Capacity limitations - dP, TSM removedS/C Ratio 3.3 3.5 3.2Outlet temp, C 800 793 804Approach to Equilibrium EOR C -10 -12 -7CH4 slip, vol % 12 12 12Radiant Pressure drop, bar 2.8 2.8 2.3Relative Radiant duty % 100 97 99Avg. Heat flux kW/m2 75 72 75Bridgwall temp, C 950 950 948Max. Tube Skin temperature C 860 860 857

ZF-SP Reactors for Debottlenecking

Achieve capacity in excess of nameplate (~ 105 %), while utilizing design margins in SMR burners and fans

Higher average heat flux without exceeding tube design temperature

Improved temperature uniformity Extended tube life and improved reliability and availability Better catalyst performance and “life cycle” costs Extended EOR Optimized operation and reforming severity


ZF-SP for Debottlenecking Reference ZF-Radiant

Relative Capacity, % 100 105Capacity limitations dP, TSM removedS/C Ratio 3.3 3.1Outlet temp, C 800 810Approach to Equilibrium C -10 -7CH4 slip, vol % 12 12Radiant Pressure drop, bar 2.8 2.5Relative Radiant duty % 100 103Avg. Heat flux kW/m2 75 77Bridgwall temp, C 950 950Max. Tube Skin temperature C 860 860


Pre-reforming


In-situ efficient use of higher grade convective heat using existing process coils

Syngas

SteamMethane

Mixed feed

Convective zoneFlue gas to stack

Radia

nt Zo

ne

AdiabaticPre-

reformer

Adiabatic pre-reforming

(APR)

ZoneFlowTM

Presenter

Presentation Notes

ZFRT has developed CPR with superior properties to conventional APR: The catalyst is on our metal substrate so no crushing occurs Catalyst is installed in existing convection coils, so external pressure vessels and interconnect piping is eliminated Higher H2 production in the convection section occurs, approx. 25% of total SMR production dP is lower in the CPR Catalyst will not need replacement in between shutdowns. Cost is significantly reduced as external equipment is eliminated

ZF Convective Pre-reforming (ZF-CPR)


Non-adiabatic convective pre-reforming using ZF-CPR inserts In-situ horizontal loading in the mixed feed superheat coils Avoids major modifications around the primary reformer and

also the related extended downtime Tailored structured packing for very low dP, high GSA and (low

temp reforming) activity Further optimization of dP in combination with ZF-SP in SMR

radiant tubes For revamps, up to 15% additional reforming without increasing

SMR firing duty.

ZF-CPR based Revamping

Existing ZF + CPRRelative Capacity, % 100 115S/C Ratio 3.4 2.8SMR inlet temp, C 550 550 / 575 1)SMR outlet temp, C 804 804 / 821 2)Approach to Equilibrium C -10 -7CH4 slip, vol % 12 13.2 / 12Radiant Pressure drop, bar 2.5 2.3Avg heat flux kW/m2 75 75-77Relative Radiant duty 100 100 / 103Bridgewall temp, C 950 < 960TSM C 860 845/ 865 1) 2)


* Exploiting of existing plant design margins, tube skin and bridgewall temps increase are minimum with lower ATE and enhanced heat transfer

Post Reforming integration with Secondary reformer

24Confidential information of ZONEFLOW REACTOR TECHNOLOGIES, LLC

Courtesy KBR

Expansion Revamp Using Post-Reforming

Post-reforming is a proven solution for 25-30% additional H2 without increasing SMR radiant duty.

Proportionate N2 from process air circuit revamping Post-reformer is a heat transfer-limited convective heat

exchange reformer ZF-PR can significantly lower the size and cost of post-

reformer because of its heat transfer and dP advantages When combined with CPR, can provide upto 40%

additional equivalent H2


ZF Post-Reforming + CPR based Revamp

Existing ZF-PR + CPRRelative Capacity, % 100 135S/C Ratio SMR / PR 3.4 3.0Inlet temp SMR / PR C 550 550 / 575 Outlet temp, SMR / PR tube C 804 804-820* / 915CH4 slip SMR / PR vol % 12 12 / 3.5Seco Reformer outlet temp, C 980 1020H2/N2 ratio in MUG 3.0 2.9 -3.1Total inerts in MUG vol % 1.5 ~ 2.5Relative SMR radiant duty 100 100


* Exploiting of existing plant design margins, tube skin and bridgewall temps increase are minimum; with lower ATE and enhanced heat transfer

Conclusions

SMR performance governed mainly by its catalyst Current pellet-catalysts carry inherent deficiencies, especially

for uprating ZoneFlowTM Reactor Technologies (ZFRT) innovative structured

catalyst offers exceptional solutions for cost-effective reformer capacity increase for ammonia plant revamps, with OPEX and CAPEX benefits.

Successful demonstrations and pilot plant for testing under commercial / client-specific conditions

ZoneFlowTM reactors carry unmatched merits and benefits for cost-effective revamping of ammonia plant front ends .


ZoneFlow Reactor Technologies, LLC


For additional information, contact:Sanjiv RatanDirector of Marketing and Prod [email protected]+1-951-538-5501

Thank You !

mailto:[email protected]

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Novel Approach to Ammonia Plant Revamps with ZoneFlow ...zoneflowtech.com/wp-content/uploads/2018/02/Nitrogen-2018-ZFRT... · cost-effective revamping of ammonia plant front ends