headerdrawing1.jpg (96365 bytes)

Sulphuric Acid on the WebTM Technical Manual DKL Engineering, Inc.

Knowledge for the Sulphuric Acid Industry Line.jpg (1139 bytes)

Sulphuric Acid on the Web

Introduction
General
Equipment Suppliers
Contractor

Instrumentation
Industry News
Maintenance
Acid Traders
Organizations
Fabricators
Conferences

Used Plants
Intellectual Propoerty
Acid Plant Database
Market Information
Library

Technical Manual

Introduction
General

Definitions
Instrumentation
Plant Safety
Metallurgial Processes
Metallurgical
Sulphur Burning
Acid Regeneration
Lead Chamber
Technology
Gas Cleaning
Contact
Strong Acid
Acid Storage
Loading/Unloading

Transportation
Sulphur Systems
Liquid SO2
Boiler Feed Water
Steam Systems

Cooling Water
Effluent Treatment
Utilities
Construction
Maintenance
Inspection
Analytical Procedures
Materials of Construction
Corrosion
Properties
Vendor Data

DKL Engineering, Inc.

Handbook of Sulphuric Acid Manufacturing
Order Form
Preface
Contents
Feedback

Sulphuric Acid Decolourization
Order Form
Preface
Table of Contents

Process Engineering Data Sheets - PEDS
Order Form
Table of Contents

Introduction

Bibliography of Sulphuric Acid Technology
Order Form

Preface
Contents

Sulphuric Acid Plant Specifications
 

Google Search new2.gif (111 bytes)

 

log 2.JPG (76785 bytes)

Sharplex.jpg (28953 bytes)

MAHLEInd.jpg (21078 bytes)

 


Materials of Construction - Quench Towers
June 8, 2003

Introduction
Tower Shell
Lining
        Rubber
Acid Brick
Carbon Brick
Spray Nozzles and Feed Pipes
PTFE
Silicon Iron
Metals
Associated Links

Gas Cleaning System - Quench Systems


Introduction

 

Back to Top

Tower Shell

The tower shell is generally carbon steel which has been lined with a corrosion resistant lining.  Once the gas has been quenched and cooled, the materials of construction can be changed to a plastic material or FRP.

Back to Top

Lining

The lining will be dependent in the gas and circulating liquid composition as well as the temperature of the gas.

Back to Top

Rubber

A rubber lining is used to prevent the weak acid from attacking the carbon steel shell .  The type of rubber used will vary from application to application.   Natural and chlorobutyl rubber are two types of rubber that have been specified for the service.  The selection of the type of rubber will depend on the availability, cost, installation requirements, etc.  If the ambient temperature of the site is low, chlorobutyl rubber should be specified due to its better low temperature flexibility over natural rubber.  The minimum thickness of rubber is generally 5 mm.

The maximum operating temperature is 60°C (140°F).  Brick thicknesses should be specified to achieve this temperature at the rubber lining.

Back to Top

Acid Brick

At least one layer of acid resistant brick is required to protect the rubber lining from the high gas temperatures especially in the region of the gas inlet.   Multiple layers of brick are preferred as this provides an added degree of safety if a flaw or crack should develop in the outer layer.  Each additional layer of brick is laid so as to stagger the joints.  This eliminates any direct paths to the rubber lining should a crack develop in the mortar. 

The mortar used to lay the acid brick should be a furan mortar.  The mortar is applied with a trowel to the sides of the brick before laying it in the course.   Either a red shale or fireclay brick is suitable for the service.  If there is no requirement for an outer layer of carbon brick, a fireclay brick is recommended due to its greater resistance to thermal shock.  If a layer of carbon brick will be laid on top of the acid brick, the less expansive red shale brick can be used.

Back to Top

Carbon Brick

Carbon brick is required when there are fluorides present in the gas and circulating liquid.  Fluorides will attack the silica in the acid brick resulting in failure of the acid brick lining.  A single layer of carbon brick laid on top of the layer(s) of acid brick will prevent fluoride attack.  A thin layer of carbon filled furan mortar (3 mm) is trowelled on top of the acid brick prior to laying the carbon brick.

The mortar use to lay carbon brick should be furan mortar.  As with the acid brick, the carbon brick is laid by applying mortar to the sides of the brick before laying it in the course.

Carbon can be oxidized if the brick is exposed for prolonged periods to the hot gas with no liquid flowing over the brick surface.  Risk of oxidization occurs when the gas temperature exceeds 350°C .  The design of the tower should ensure that the carbon brick is not exposed to the hot gas without liquid flowing on the brick surface.

Specification: Low-Ash Chemical Carbon Brick

Back to Top

Spray Nozzles and Feed Pipes

Many materials have been specified for quench tower service.  The selection of a suitable material will be dependent on the gas and liquid compositions, gas and liquid temperature, mechanical strength, resistance to abrasion and wear, etc. 

Back to Top

PTFE

PTFE has excellent resistance to chemical attack and is suitable for all gas and liquid compositions.  However, PTFE lacks mechanical strength at high temperatures.  PTFE nozzles are best suited for counter-current tower designs where they are not exposed to hot gases.

Back to Top

Silicon Iron

Silicon iron is resistant to most gas and liquid compositions that are found in typical quench tower applications.  The material has excellent resistance to abrasion and wear due to solids in the circulating liquid.  However, silicon iron is brittle and can break easily if there is excessive mechanical forces exerted on the nozzle or feed pipe.

Back to Top

Metals

There are some metals that maybe suitable for spray nozzles and feed pipes depending on the gas and liquid compositions.  Hastelloy C-276, G, X, alloy 20, stainless steel maybe specified for the service.  Careful study of the suitability of the metal must be done before specifying it.

Back to Top