Optimizing Tower Designs - H2so4today...3” mm Ceramic Saddles vs. Flexeramic 88 Parameter B ase...

CONFIDENTIAL – © 2018 All Rights Reserved

Optimizing Tower Designs

Koch Knight, LLC

Matthew J. Thayer

November 8 2018


Table of contents

Brief history of the plant sizing- Break down was based on the following sizes: 500,1000, 2000, 3000, 4000, 5000 MTPD

Discovery and analysis of the issues surrounding the larger plant

Options to correct the issues associated with these larger plant Reduction of the stress and the loads on the bricks Reduction in the diameter of the towers

Repair of the existing tower options

Conclusion


Looking at the raw data

Reviewed more than 100 towers Ages of the plant varied from less than one year to 20 plus years

Data gathered on both brick lined and metallic towers, some of the data gathered: Age if the plant Diameter Tower type – Brick and Metallic Brick Types- Red shale vs Acid proof Membrane type Environmental averages Limited information on Seismic and wind loading


Main Issue Discovered –Next Steps As the tower diameter increased, more issues were identified

Failure/repair requirements of the external shell occurring faster as the diameter of the shell increased

Perform an FEA on the shell to see if any specific issues could be uncovered – Simple base case to determine if there is an issue.

Categorized raw data on the towers and focused in on three items: • Membrane type • Size of the tower • Repairs of the existing tower


FEA Evaluation


General Modeling of the shell

Figure 1: Model of lining system for PYROFLEX® acid resistant sheet lining case.

DURO™ Acid Brick II-P 2 x 65 MM

Process temperature (130°C)

Inside diameter

Ambient Conditions

(-‐20°C to 30°C)

Stee

l she

ll (1

2.7m

m)

Pyro

flex

(9m

m)


2 Meter Radial No Membrane

Figure 2: Radial displacement of the 2-meter diameter tower without membrane.


9 Meter Radial No Membrane

°C

Figure 3: Radial displacement of the 9m diameter tower without a membrane.


2 Meter Radial With Membrane

Figure 4: Radial displacement of the 2-meter diameter tower with PYROFLEX membrane.


9 Meter Radial With Membrane

Figure 5: Radial displacement of the 9-meter diameter tower with PYROFLEX membrane.


Gap Between Refractory and PYROFLEX/Steel Shell

ID = 2000 mm ID = 9000 mm

With PYROFLEX

No PYROFLEX

With PYROFLEX

No PYROFLEX

Cold Ambient No Gap No Gap No Gap No Gap

Warm Ambient No Gap No Gap No Gap 0.3 mm Gap

Displacement Summary

Figure 6: Comparison Gap Data Recap


Dome Displacement

Figure 6: Radial displacement at packing support when the tower is in operation at 130°C with 30°C ambient temperature


PYROFLEX™ PTFE DuPly Membrane/Brick


Change the Packing


Plant Sizing

Size of the plant 75 mm Nom Saddles (Dia.(M)/Vol)

FLEXERAMIC® 88 Packing (Dia./Vol)

500 MTPD 3400 / 30 2800 / 20

1,000 MTPD 4700 / 50 4000 / 40

2,000 MTPD 6700 / 110 5700 / 80

3,000 MTPD 8200 / 160 7000 / 110

4,000 MTPD 9500 / 210 8100 / 150

5,000 MTPD 10600 / 260 9000 / 190


Comparison to random packings 3” mm Ceramic Saddles vs. Flexeramic 88

Parameter Base Case

ΔP Reduction

Increased Efficiency and ΔP

ReductionIncreased Capacity

Increased Capcacity

and Efficiency

New Smaller Tower

Packing 75 mm FX 88 FX 88 FX 88 FX 88 FX 88Diameter 20'0" 20'0" 20'0" 20'0" 20'0" 17'3"Packed Height 12' 9' 12' 9' 12' 9'Gas Flow (lb/hour) 500,000 500,000 500,000 650,000 650,000 500,000Acid Rate (gpm) 4,700 4,700 4,700 6,100 6,100 4,700Pressure Drop (" w.c.) 8 3 4 7 8 8% Flood at Bottom (Max.) 73% 54% 54% 77% 77% 80%SO3 Removal 99.98% 99.98% 100.00% 99.98% 100.00% 99.98%


Benefits in Sulfuric Acid Service• Reduced tower size (Reduce capital costs of new units and

provide flexibility in replacement options)

• Reduced stress in the tower

• Increased capacity (Debottleneck existing units)

• Increased efficiency (Remedy for undersized units)

• Robust design


REPAIR METHODS


Failure Inside An Acid Tower

1. Acids inherently find ways to permeate through brick and mortar

2. Once penetrated to the membrane, the acid slowly converts the surface of the protective barrier to carbon.

3. Carbon is stable, as long as it is not washed away due to continuous flow of acid.

4. Once carbon is washed off, carbon steel meets acid creating iron sulfide. The same wash process occurs and reduces thickness of wall finally perforating it.

Brick

Mortar

Membrane

Carbon Steel

Acid


Repair Methods Available

1. Some try to weld another steel plate on top of the acid leak. Welding will destroy the existing membrane creating even more problems.

2. Another way is trying to fill the voids between steel shell and brick lining with some kind of acid resistant materials: • Potassium Silicate would be the

oldest way of repairing • Pecora Mastic was an improvement • With newer low viscosity acid

resistant resins on the market providing different ways of repair.


Potassium Silicate

How do we get the potassium silicate to stay in place? It is brittle and reacts immediately with acid to form a solid. • Weld a box to the steel shell and try to fill

the voids with mortar • A thick and highly viscous material that will

not flow easily into the void and will only deliver a temporary solution.

• Lots of post maintenance required.

Brick

Mortar

Membrane

Potassium Silicate

Acid


PECORA® INJECTION

The next best solution is to inject Pecora Mastic into the voids. • The material is thick and highly viscous • Material needs to be heated and mixed with

a solvent to be injected properly into voids • An even distribution throughout the void

cavity is obtainable • Solvents evaporate creating pathways for

acid within the material.

Brick

Mortar

Membrane

PECORA® Mastic

Nipple / Injection


PECORA® INJECTION

•With pathways created flow will continue getting once again to the steel shell.

•New Steel Perforation will appear

•Let’s start from the beginning once again!

Brick

Mortar

Membrane

Acid


NOVOLAC INJECTION

As said before is a specifically developed resin resistant to high corrosive acids and creates an array of solutions to injecting void spaces between steel and brick linings. • Low Viscosity • With a low pressure injection machine

voids can be fully filled • Resin Reacts with acid, but flow pushes the

reacted resin out • Penetrates small cracks

Brick

Acid

Mortar

Membrane

Novolac


NOVOLAC INJECTION

• As it is a 100% solids material (no VOC) it hardens and cures to form an Acid Resistant Membrane

• Minimal to Nil Voids Cutting off flow for “ New Acid Highways”

• Can be re-injected at new ports any time to catch places which were not treated before.

Brick

Acid

Mortar

Membrane

Novolac


Lay out and drilling of the tower


Special Thanks

Steve Purchelli – Saconix

John Horn – MECS/Dupont

Rick Davis – Rick Davis Consulting

George Wang – GWang Consulting

Dr. Hannes Storch – Outotec

Jan DuPlessis Theron - Lucideon

English


Thank you for your time

Any questions?

English

Optimizing Tower Designs - H2so4today...3” mm Ceramic Saddles vs. Flexeramic 88 Parameter B ase...

Documents

Transcript of Optimizing Tower Designs - H2so4today...3” mm Ceramic Saddles vs. Flexeramic 88 Parameter B ase...