1. SCOPE……………………………………………..2. REFERENCES
3. DEFINITIONS
4. GENERAL …………………………………………5. QUALITY ASSURANCE
6. PROPOSAL
7. DOCUMENTATION …………………………….8. MATERIAL
8.1 General
8.2
Types of Refractory ………………………..
8.3
Refractory Specification Sheet
8.4
Available Materials
9. MATERIAL SELECTION ……………………..9.1 General
9.2
Refinery Fired Heaters
9.3
Reformers in Ammonia and Hydrogen
Plants …………………………………………..9.4
Cracking Furnaces in Ethylene Plants
9.5
Boilers
9.6
Incinerators …………………………………..
9.7
Refractory Lined Heat Exchangers
9.8
Refractory Lined Pressure Vessels
and Piping
9.9
Steel Mill Furnaces…………………………
10. THERMAL DESIGN
10.1 General
10.2 Heat Loss Calculation …………………….10.3 Temperature Profile Calculation
FIGURE
1 Single Fired Furnace, Vertical
Cylindrical and Cabin Type
2 Double Fired Furnace ………………………..3 Primary Reformer – Terrace Wall Type 4 Ethylene Cracking Furnace
5 Package Boiler Setting Details……………..6
Incinerator Combustor
7 Refractory Lined Heat Exchanger
Inlet Channel and Tube Sheet
8 Simplified Sketch for FCC Reactor,
Regenerator and Accessories ……………..9 Refractory Linings for HDS Reactor
10 Refractory Linings for Spherical Type
Catalytical Reformer
11 Sulfur Plant Thermal Reactor ……………….12 Secondary Reformer
13 Refractory Temperature Profiles for
Different Lining Combination
TABLE
I
Refractory Linings for Heat Exchangers..
II
Refractory Linings for Fluid Catalytic
Cracking
Unit
III Refractory Linings for HDS Reactor
IV Refractory Linings for Catalytic ReformerReactor …………………………………………….V
Refractory Linings for Sulfur Recovery
Unit
VI Refractory Linings for Transfer Line
and Secondary Reformer
VII Refractory Linings for Steel Mill
Furnaces …………………………………………..
APPENDIX
A Refractory Specification Sheets
1. Fireclay Brick
2. High Alumina Brick …………………….3. Basic Brick
4. Special Purpose Brick
5. Insulating Firebrick …………………….6. Insulating Castable
7. Refractory Castable
8. Gun Mix Castable ………………………9. Plastic Castable
10. Ramming Mix Castable
11. Ceramic Fiber Blanket ………………12. Ceramic Fiber Module
13. Ceramic Fiber Block
1. Scope
1.1 This specification is for application and selection of refractory materials for fired heaters, ethylene
cracking furnaces, ammonia or hydrogen reformers, pressure vessels, boilers and incinerators commonly
used in the refinery, petrochemical and power industries.
1.2 This specification also provides methods for calculating heat loss through refractory layers, and
inter-layer temperature profiles in multi-component refractory systems.
2. References
Reference is made in this specification to the following documents. The latest issues, amendments, and
supplements to these documents shall apply unless otherwise indicated.
SABIC Engineering Standards (SES)
N02-C01 Castable Refractory – Design and Installation
N02-C03 Refractory Bricks – Design and Installation
N02-C04 Ceramic Fiber – Design and Installation
Q01-F07 Pressure Vessels – Fabrication
Q01-G02 General Specification for Surface Preparation and Painting
Q01-T01 Testing and Inspection
Z01-G04 Measurement Units for Use in SABIC Projects
International Organization for Standardization (ISO)
9001 Quality Systems – Model for Quality Assurance in Design, Development, Production, Installation
and Servicing
9003 Quality System – Model for Quality Assurance in Final Inspection and Test
9004 Quality Management and Quality System Elements – Guidelines
3. Definitions
For the purpose of understanding this specification, the following definitions apply.
Bricks. Shaped refractory materials including insulating fired bricks, basic bricks, fireclay brick, silica
bricks, special purpose refractory bricks.
Castable Refractory Materials. ‘Ready mixed’ monolithic refractory materials delivered dry and which
require mixing with water or other liquids. They are placed by casting, trowelling, vibrating, rodding,
tamping, or pounding, and harden at ambient temperature.
Ceramic Fiber Modules. Blocks manufactured of continuously folded and compressed ceramic fiber
blanket.
Devitrification. The change from a glassy to a crystalline condition. The rate of change is a function of
time and temperature for a specific refractory. Devitrified fiber blanket, for example, becomes friable
(powder) at high temperature over time.
Gunning Refractory Materials. Monolithic refractory mixtures that are non-coherent before use; specially
prepared for placing by pneumatic or mechanical projection.
Monolithic Refractory Materials. Mixtures of aggregates and binders used either directly in the supplied
condition or after the addition of a suitable liquid, and having a pyrometric cone equivalent (PCE) of at
least 1500 °C. These mixtures are either dense or insulating refractories. The true porosity for insulating
refractories shall be more than 45 percent. Even though some insulating refractories have a PCE lower
than 1500 °C, they are still considered as refractory materials.
Plastic Moldable Refractory Materials. Monolithic refractory materials which are either supplied moist
and ready to use, or require moistening into a workable consistency. They are prepared for direct
installation as bulk or in cakes.
Porosity. The ratio of the volume of the pores or voids in a body to the total volume, usually expressed as
a percentage. The ‘true porosity’ is based on the total pore volume; ‘apparent porosity’ on the open pore
volume only.
Refractory. Non-metallic material used as products that include dense, insulating, acid resistant and
special composite materials for linings within heaters, boilers and other equipment and piping, to protect
steel from heat, erosion, acids or other service conditions.
Sintering. A heat treatment which causes adjacent particles of material to cohere at a temperature below
that of complete melting.
4. General
4.1 Documents shall be provided in units conforming to SES Z01-G04, and shall be written in English
language.
4.2 Conformance to all applicable regulations, for example Royal Commission Environmental Guides,
Meteorological and Environmental Protection Agency (MEPA) and Occupational Safety and Health Agency
(OSHA) shall be required.
4.3 Any conflict(s) between this specification, SES and industry standards, engineering drawings, and
contract documents shall be resolved at the discretion of SABIC.
5. Quality Assurance
Manufacturer’s quality assurance program shall conform to SES Q01-F07, Q01-T01, ISO 9001, 9003 and
9004. Quality assurance program shall provide for the planned and systematic control of all quality related
activities performed during design, engineering, fabrication, installation, or servicing (as appropriate to the
given system), and shall, along with all related reference procedures, be submitted for SABIC review and
approval.
6. Proposal
6.1 Manufacturer shall submit proposal for base design in accordance with contract documents and this
specification. However, manufacturer may submit an alternative design, if in his judgment, the alternative
can improve the schedule or reduce the overall cost, or both, with no impact on the performance and
service life of refractory material and the equipment.
6.2 Manufacturer shall furnish the following information with proposal:
a. Any exceptions or clarifications to the contract documents, SABIC Engineering Standards and
other specifications
b. Complete description of the lining system for the equipment provided, with type of refractory
materials, rating, grade, thickness, type of anchor, and anchor materials in various parts of equipment
c. Technical data sheets for the refractory material supplied by manufacturer. Information shall
include the following:
(i) Complete chemical analysis
(ii) Types of aggregate and cements used
(iii) Pyrometric cone equivalent (PCE)
(iv) Maximum service temperature for specific service condition
(v) Density
(vi) Permanent linear change
(vii) Hot and cold modulus of rupture
(viii) Thermal conductivity
(ix) Cold crushing strength
(x) Water requirements for castable refractories
(xi) Thermal expansion
(xii) Hot load deformation
(xiii) Young’s modulus of elasticity
(xiv) Reheat change
(xv) Workability index for plastic refractories
(xvi) Abrasion loss
(xvii) Apparent porosity
(xviii) Quantity of material needed for each application
(xix) Storage requirements
(xx) Material shelf life and packaging
(xxi) Losses, for example spoilage and rebound
(xxii) Mixing procedure
(xxiii) Surface preparation required
(xxiv) Installation procedures
(xxv) Curing and drying requirements
(xxvi) Repair procedure
(xxvii) Anchor material, type, and quantity
d. Drawings showing general arrangement, lining details, expansion joints and anchor layout
e. A table showing quantity, dimension and estimated weight of field installed refractory to be
shipped
f. QA plan and project schedule
7. Documentation
7.1 Manufacturer shall submit the type and quantity of drawings and documentation listed in the purchase
order and contract documents for design engineer’s review and approval. If design engineer and
manufacturer are the same concern, drawings and documents shall require SABIC review and approval.
7.2 Comments made by SABIC, or design engineer on drawings or documents shall not relieve
manufacturer or their material suppliers of any responsibility in meeting the requirements of this
specification. Comments shall not be construed as permission to deviate from requirements of purchase
order or contract documents, unless specific and mutual agreement is reached and confirmed in writing.
7.3 The documentation submitted shall include the following:
a. Data Sheets. Manufacturer shall furnish refractory data sheets and material safety data sheets
(MSDS) containing all relevant information
b. Calculations:
(i) Heat loss rate at various locations
(ii) Temperature profile for all refractory lining, and anchor tip temperature
c. Drawings:
(i) General arrangement drawings for refractory and insulation, showing type, grade and rating of
refractory materials; thickness of each layer; and expansion joints
(ii) Drawings showing anchor pattern, with type, material and size. See SES N02-C01, N02-C03 and
N02-C04.
d. Reports, Certificates and Data:
(i) Material certificate or data for refractory and insulation, with chemical composition, density,
thermal conductivity, rupture and crushing strength, shrinkage, temperature rating, material packaging
and storage requirements
(ii) Inspection and testing reports confirming physical and chemical properties of the supplied
refractories, and compliance with anchor system requirements
e. Procedures and Manuals. Shipping, handling, preparation, installation, curing, dry-out, heat-up,
and cool-down procedures for the refractories supplied or installed.
8. Material
8.1 General
8.1.1 Refractory material is used extensively in fired equipment, and high temperature vessels and
reactors, for energy conservation and equipment and personnel protection.
8.1.2 Depending on mineral makeup, refractory materials have different maximum working temperatures;
corrosion and erosion resistance; and different strengths, which vary with operating temperature and
equipment environment.
8.1.3 Unfired (green) refractory consists of a mixture of refractory particles varying from coarse to
extremely fine sizes. Coarser particles may be 6 mm or more in diameter, and the fines may pass a
200-mesh screen. After firing, the fines form the ceramic bond between larger particles.
8.2 Types of Refractory
8.2.1 Refractories installed in refinery and petrochemical plants are classified into three general categories
based on their shapes, forms and manufacturing process:
a. Brick. Shaped refractory, widely used in heaters, incinerators and boilers. See SES N02-C03.
b. Castable. A general term for monolithic refractories. These are mixes of dry, or pre-wetted
refractory materials that are cast, rammed, gunned, or trowelled into place, forming relatively joint-free
linings. See SES N02-C01.
c. Ceramic fibers. Formed by melt spinning or air blowing of molten mixtures of alumina and silica,
sometimes combined with other oxides. Used as hot-face material in applications where corrosion and
erosion are not severe. See SES N02-C04.
8.2.2 Each category of refractory material can be further classified into different groups and grades based
on its refractoriness, composition, physical properties, and use.
8.3 Refractory Specification Sheet
Refractory specification sheets (RSS) have been developed for various types of refractories used in
refinery and petrochemical industries. The specification sheets specify the minimum requirements for
composition, physical and chemical properties, and mechanical strength. Materials in this specification use
the designated numbers of RSS. See Appendix A.
8.3.1 Each refractory material is designated in RSS by two or three letters as a prefix, followed by a
hyphen and then by either a number or combination of letters and number.
8.3.2 The construction of material designation in RSS is illustrated as follows:
a. Functional classification is described in RSS, and is self-explanatory.
b. There are only three types of refractories under ‘Type of Refractory’ in 7.3.2:
(i) B – brick/block
(ii) C – castable
(iii) F – fiber
c. The ratings usually represent service temperature, in hundreds of degrees Fahrenheit; alumina
content in percent; or density in pounds per cubic foot.
d. Therefore, RSS IFB-23 represents minimum requirements for insulating firebrick of 1260 °C
(2300 °F) grade.
8.4 Available Materials
8.4.1 Commercially available refractory materials conforming to RSS are listed in Appendix A.
8.4.2 No substitution for materials in Appendix A shall be made without written SABIC permission.
9. Material Selection
9.1 General
9.1.1 Selection of refractory material shall be based on the following considerations:
a. Equipment configuration and arrangement
b. Equipment operating conditions from start up to maximum capacity
c. Process fluid or flue gas temperature and velocity profile axially and longitudinally inside the
equipment or vessels, under each operating case in 9.1.1.a
d. Process fluid or flue gas characteristics, for example compositions, physical and chemical
properties, and erosive and corrosive nature
e. Rate of temperature increase of equipment (ramp up rate)
f. Resistance of refractory materials to high temperatures and temperature fluctuations
g. Chemical and mechanical resistance of refractory materials to contact materials
h. Refractory materials shall be mechanically strong enough to withstand loads during construction,installation, normal operation and maintenance
i. Refractory material shall be able to withstand high velocity combustion environment, when
required
9.1.2 General advantages of brick as refractory material are:
a. Suitable for all kinds of fuel and harsh operating environments
b. Can be self-supported (without anchors) with special design configuration
c. Excellent for burner flame zone or hot face layer
d. Resistant to corrosion, abrasion, erosion, particulate or slag impingement
e. Capable of carrying loads, hot and cold
9.1.3 General advantages of castable as refractory material are:
a. Suitable for all kinds of fuel and harsh operating environments
b. Free of restrictions in shape or form – compared to brick
c. Easy and fast installation – compared to brick design
d. More economical for multiple component installation – compared to brick design
e. Resistant to corrosion, abrasion, erosion, particulate or slag impingement, and other harsh
operating atmospheres
f. Capable of carrying loads, hot and cold
9.1.4 General advantages of ceramic fiber as refractory material are:
a. Light weight – compared to brick and castable
b. Less susceptible to thermal shock damage than brick or castable
c. Low heat storage, giving fast start-up
d. Does not require curing
e. Less expensive, easier and faster installation than brick or castable
9.1.5 General disadvantages of brick as refractory material are:
a. Restricted by shape and size
b. Labor intensive in installation – requires mortar; special shape bricks and layout in some areas,
for example arches and corners; lintel plates; and rods and pins for support
c. Multi-layer installations are expensive
d. High heat storage
e. Moderate heat up and cool down rates
9.1.6 General disadvantages of castable as refractory material are:
a. Mixing is required
b. Surface preparation required
c. Requires curing and dry-out before operation
d. Requires anchor support
e. Not suitable for ceramic fiber blanket or module as back-up layer
f. High heat storage
g. Requires slow heat up and cool down
9.1.7 General disadvantages of ceramic fiber blanket and module are:
a. Light and porous, susceptible to attack from fume, particulate and slag
b. Not suitable for heavy fuel oil or reducing atmosphere conditions
c. Can not be used in burner flame zone
d. Not suitable for areas where flue gas velocity exceeds 10 m/s
e. High shrinkage rate due to sintering and devitrification
f. Vitirifies and become friable – temperature and time dependent
9.1.8 Selection criteria for ceramic fiber blanket/module:
a. Fiber blanket or module shall only be used for gas fuel with low sulfur content (less than 50 mL/L)
b. Blanket shall be used for gas velocity less than 10 m/s, and module for lower than 15 m/s
c. Ceramic fiber blankets or modules shall not be used in burner flame zone
d. Fiber blanket or module with less than 3 percent shrinkage rate at maximum rated temperature
application shall be selected
e. Blanket, module, and anchor support layouts shall be designed in accordance with
SES N02-C04
9.1.9 Ceramic fiber modules shall be preferred over blanket installation for the following reasons:
a. Blanket shrinkage causes it to pull loose from or tear away from studs and clips
b. Blanket exposes studs, clips and metal casing to furnace atmosphere after shrinkage
c. Blanket is more expensive to install and repair
d. Blanket has lower utility life than modules
9.2 Refinery Fired Heaters
9.2.1 Fired heaters for general refinery service are usually operated at radiant section temperatures of
approximately 650 °C to 980 °C. Refractory lined radiant walls are either shielded by the radiant wall tubes
(single fired) or exposed to hot flue gas or even burner flame (double fired). Representative single and
double fired heater arrangements and refractory types are shown in Figures 1 and 2.
9.2.2 Selection of refractory material for refinery heaters shall be based on the following considerations:
a. Refinery fuel characteristics and combustion product from the burners
b. Type and arrangement of the fired heater, for example vertical cylindrical type, cabin with
horizontal tubes, and box type with double-fired vertical tubes
c. Burner configuration, firing pattern and flame dimension
d. Flue gas temperature and velocity profiles inside the furnace
e. Flue gas constituents concentration profile in furnaces fired with heavy fuel oil, for example soot,
sulfur oxides, vanadium oxides, and other erosive or corrosive components
f. Resistance of refractory materials to high temperatures and temperature fluctuations
g. Chemical and mechanical resistance of refractory materials to substances that come in contact
with them
h. Refractory materials shall be mechanically strong enough to withstand loads during construction,
installation, normal operation and maintenance
i. Refractory material shall be able to withstand conditions encountered with high velocity
combustion system when used
9.2.3 Heater floor shall be laid with 64 mm fired brick FCB-3, or 75 mm heavy weight castable RC-6.
Back-up layer shall be a minimum of 150 mm medium weight insulating castable IC-20. Thickness for back
up layer shall be calculated in accordance with 10.2 and 10.3 to satisfy heat loss and casing temperature
requirements.
9.2.4 Refinery fired heaters using fuel gas with sulfur content less than 50 mL/L may use ceramic fiber
blanket or module in the radiant section for single fired shielded walls, or double fired exposed walls,
when:
a. Burners are not mounted on the fiber walls
b. The face velocity on modules or blanket does not exceed that specified in 9.1.8.b
c. Burner flame does not lick or impinge on the fiber surface
9.2.5 Ceramic fiber blankets or modules used for hot face layer shall be of 128 kg/m3
density, 1260 °C
grade CF-1 or CF-M1.
9.2.6 Back-up layer for fiber blankets shall be 96 kg/m3
density, 1260 °C grade CF-1. No back-up layer
shall be required for ceramic fiber modules.
9.2.7 Material selection for studs, washers, clips and anchoring system used in blanket or module design
shall be in accordance with SES N02-C04.
9.2.8 Ceramic fiber blanket or module shall not be used in high velocity convection section areas unless it
is protected by a layer of stainless steel shroud plate or sprayed rigidizer, and subject to design engineer’s
approval.
9.2.9 For heater firing with clean fuel gas, a minimum of 75 mm thick insulating castable IC-22, shall be
used as hot face layer. For a two-component design, the back-up layer shall be IC-20.
9.2.10 Stack shall be lined with 50 mm minimum thickness of castable refractory, IC-20 or IC-22. Unlined
stack shall be acceptable when specified by design engineer.
9.2.11 For heaters with wall mounted burners or radiant burners, the radiant walls shall be lined with bricks
or castable. Fiber material shall not be used unless conditions in 9.2.4.b and 9.2.4.c are satisfied.
9.2.12 Bricks as hot face layer for fired walls in the refinery heater firing clean fuel gas shall be 114 mm
thick IFB-26 minimum. Back up layer shall be block insulation CF-B2.
9.2.13 Castable as hot face layer for fired walls in the refinery heater firing clean fuel gas shall be 100 mm
thick IC-26 minimum. Back up layer shall be light weight castable IC-20.
9.2.14 For heaters fired with fuel oil, selection of refractory materials shall be based on considerations
in 9.2.2 and the following:
a. Fuel oil characteristics, especially vanadium, sodium, sulfur and ash content
b. Combustion products formed under various operating conditions, especially those elements that
are either corrosive, erosive or detrimental to certain refractory materials. Oxides of vanadium, sulfur,
and sodium, and slag or soot are some of the elements harmful to insulating refractories.
c. Selecting refractory materials that are most resistant to, or most effective in combating, the attack
from specific harmful elements
9.2.15 When the fuel fired contains more than 400 mg/kg of vanadium plus sodium, the refractory hot face
layer shall be HAB-60 or RC-2. The overall alumina (Al2O3) content shall be 40 percent minimum, with no
less than 40 percent Al2O3 in aggregate. Silica (SiO2) content shall be 35 percent maximum.
9.2.16 For fuel oil containing 0.5 wt percent sulfur, the hot face layer refractory material shall be a
minimum of medium weight, containing less than 10 percent of magnesia (MgO) and iron in the aggregate.
Castable GMC-2 shall be acceptable.
9.3 Reformers in Ammonia and Hydrogen Plants
9.3.1 Reformers, also commonly referred to as steam-methane reformers (SMR) or primary reformers, are
used to convert methane, light hydrocarbon gas or naphtha into hydrogen in the catalyst filled reactor
tubes. Numbers of catalyst tubes are arranged in rows in a combustion chamber where burners are fired in
between tube rows. Feed gas is distributed to, and the reformed gas is collected from, the primary reformer
via inlet and outlet manifolds. The reformed gas is then delivered to downstream equipment for further
processing. Typical types of primary reformer firebox and refractory are shown in Figure 3.
9.3.2 Most reformers are fired with gas fuels, typically purge gas, off-gas, and natural gas or refinery fuel
gas. Liquid fuels are rarely used in the reformer for economic and environmental reasons, therefore only
refractory material selection for gas fuel is considered in this section. For cases with liquid fuel firing, 9.2.14
to 9.2.16 shall be followed.
9.3.3 Refractory lining in the hydrogen plant reformer or ammonia plant primary reformer shall be
designed for service process and furnace operating conditions in a specific furnace environment. There
are four main types of reformer design:
a. Top fired reformer in which multiple vertical tube lanes are housed in a refractory lined firebox,
and the burners are fired downward, between tube lanes
b. Side wall fired reformer in which multiple levels of burners fire from both sides of the furnace
firebox into a single in-line or double staggered catalyst tube lane(s)
c. Terrace wall reformer, which is a two-tier firing, sloping side wall fired box
d. Bottom fired reformer with two catalyst tube lanes in a firebox, and burner lanes between tube
lanes
9.3.4 For top fired reformer, firing gas fuel, the lining for the firebox shall be as follows:
a. Side walls – 230 mm ceramic fiber module CF-M2, 149 kg/m
3
minimum bulk density
b. End walls – 230 mm ceramic fiber module CF-M2, 149 kg/m
minimum bulk density
c. Arch – 300 mm ceramic fiber module CF-M2, 149 kg/m3
minimum bulk density
d. Floor – 114 mm firebrick FCB-2 + 230 mm insulating castable IC-22
e. Flue gas tunnel – straight bricks of FCB-2
3
9.3.5 For side wall fired reformer, the lining for the firebox shall be as follows:
a. Side walls or fired walls – 64 mm insulating firebrick IFB-26 + 114 mm insulating firebrick IFB-23
+ 75 mm block insulation CF-B2
b. End walls – 64 mm insulating firebrick IFB-26 + 114 mm insulating firebrick IFB-23 + 75 mm block
insulation CF-B2
c. Arch – 230 mm ceramic fiber module CF-M1, 149 kg/m3
minimum bulk density
d. Floor – 114 mm firebrick FCB-2 + 230 mm insulating castable IC-22
9.3.6 For terrace wall reformer, the refractory lining for the firebox shall be as follows:
a. Side walls or fired walls – 64 mm insulating firebrick IFB-26 + 114 mm insulating firebrick IFB-23
+ 75 mm block insulation CF-B2
b. End walls – 64 mm insulating firebrick IFB-26 + 114 mm insulating firebrick IFB-23 + 75 mm block
insulation CF-B2
c. Arch – 230 mm ceramic fiber module CF-M2, 149 kg/m3
minimum bulk density
d. Floor – 114 mm firebrick FCB-2 + 230 mm insulating castable IC-22
9.3.7 For bottom fired reformer, the refractory lining for the firebox shall be as follows:
a. Side walls, 2 m from floor – 114 mm insulating firebrick IFB-26 + 150 mm ceramic fiber module
CF-M1
b. End walls, 2 m from floor – 114 mm insulating firebrick IFB-26 + 150 mm ceramic fiber module
CF-M1
c. Arch – 230 mm ceramic fiber module CF-M2, 149 kg/m3
minimum bulk density
d. Floor – 114 mm firebrick FCB-2 + 230 mm insulating castable IC-22
9.3.8 Material selection considerations for the convection section shall be as follows:
a. For better efficiency and economic reasons, two-component lining system shall be considered in
the hot section of the convection section, for example brick and block, or castable and block
b.
In the cold segment of the convection section, single layer castable shall be used
c. Brick used as hot face layer in the two-component system shall be IFB-23; back-up block
insulation shall be CF-B2
d.
If castable will be the hot face layer in a two-component system, the material shall be IC-22;
back-up layer shall be insulation block CF-B2
e. Single layer insulation used in the cold segment of the convection section shall be insulating
castable IC-20
9.3.9 For unlined stack, the internal surface shall be coated with coal tar epoxy or corrosion resistant paint
in accordance with SES Q01-G02.
9.3.10 For lined stack, the refractory lining shall be 50 mm of castable GMC-20.
9.4 Cracking Furnaces in Ethylene Plants
Ethylene is produced by thermal cracking of hydrocarbon feed gas or liquid in a pyrolysis furnace in which
heat is supplied to a row of tubular reactor by burners firing from both sides of the tubes. Cracking severity
is related to the residence time of the feed in the tubular reactor, and affects the operating temperature of
the furnace. Natural gas, refinery fuel gas, and some by-products from the plant, for example tail gas, are
used as fuels to the furnace. A typical cracking furnace is shown in Figure 4.
9.4.1 Cracking furnaces in ethylene plants normally fire clean fuel gas including high hydrogen content tail
gas. The furnaces are either side wall fired (2 or more tiers of burners, radiant or up-shot type) or bottom
fired vertical tube box with horizontal convection section. However, combinations of bottom and side wall
fired crackers are increasing in use.
9.4.2 Refractory material selection shall be based on the following criteria:
a.
In the vicinity of burner flame or areas where flames impinge wall, the hot face layer shall be high
density, high temperature bricks. Brick type and rating will depend on burner design and cracking
severity of the furnace.
b. For high severity, low residence time (less than or equal to 0.25 s) furnaces, firing with high
hydrogen content tail gas and natural gas, the hot face layer for the flame zone shall be minimum
IFB-30. Back-up layer(s) may be castable, block or fiber module.
c. For medium and long residence time furnaces, the hot face layer for the flame zone shall be
minimum IFB-26
d. Beyond the envelope of burner flame, brick, castable or ceramic fiber modules can be used as
hot face layer for exposed surface in the radiant box. Minimum rating for fiber module shall be CF-M2.
e. Arch shall be lined with ceramic fiber modules or blanket, minimum CF-M2 or CF-2
f. Floor refractory shall be dense castable or brick RC- 6 or FCB-3; back up layer shall be insulating
castable IC-22
g. Special shaped ceramic fiber tile may be used as collar for radiant tube guide pin
h. Areas where radiant tubes penetrate arch or wall shall be sealed with ceramic fiber materials
(module, blanket, or bulk) CF-2 or CF-M2. External seal shall have tube clamp, and fiber cloth packed
with fiber.
9.4.3 For brick construction in a side wall mounted up-shot burner, the brick arch for the burner shall be
designed in accordance with SES N02-C03.
9.4.4 Refractory materials for convection section and stack shall conform to 9.3.7 to 9.3.9.
9.4.5 If combustion air is preheated, the duct shall be internally or externally insulated. If internally
insulated, the lining shall be one of IC-16, IC-20, GMC-8, or GMC-9.
9.5 Boilers
Selection of refractory materials for industrial and utility boilers will depend on the types of fuel fired, boiler
configuration and the temperature zoning inside the boilers. For example, plastic refractories are
commonly used as refractory material in water-tube-cooled burner throat, tube seals, quick patches, and in
areas in where gunning and casting of refractory materials become difficult. Setting details of a package
boiler are shown in Figure 5.
9.5.1 Ceramic fiber blankets or insulating felts may be used in oil or gas fired boilers where there will be
no flue gas contact with the exposed refractory. This type of insulation is usually for the steam drum and
head, and roof and side walls between gas tight casing and aluminum casing. Minimum density for
insulating material shall be 128 kg/m3
. Temperature rating of the material shall be a minimum of 167 °C
higher than the temperature to which the refractory will be exposed.
9.5.2 Conical burner throat formed by water tubes shall be rammed with plastic refractory materials.
Plastic refractory, minimum PC-1, shall be rammed between and over the tubes to protect the tubes from
burner flame.
9.5.3 Refractory surface exposed to the hot flue gas shall be lined with dense, erosion resistance castable
GMC-2 or RC-6.
9.5.4 Refractory penetrated by, for example, drums, tubes, and headers, shall have gas tight seals to
prevent combustion and flue gas leakage. In the example of a package boiler, these penetrations are at
the top of the mud drum, and bottom of the steam drum where the furnace tubes break tangency and enter
the drums. The voids created at these locations shall be filled with a suitable castable refractory.
9.5.5 Brick installed for boiler floor shall be minimum FCB-3.
9.6 Incinerators
9.6.1 Depending on type of waste to be disposed, and emission restriction, refractory requirements for
incinerators vary considerably. The criteria for selecting suitable refractories for intended services should
usually be confined to the following:
a. Temperature. Refractory installed in the incinerator shall be able to withstand the maximum heat
inside the combustion chamber. Limiting temperature shall be the runaway temperature excursions
under the most severe operating conditions.
b. Slag. Selected refractory shall be dense and chemically compatible with any slag likely to form
on it. Usually, the more chemically compatible a refractory is with the slag it comes in contact with, the
more resistant it is to slag attack.
c. Chlorine or Fluorine in Flue Gas. The presence of chlorine or fluorine in flue gas will prevent the
use of castables, as they will attack the lime (CaO) binder and destroy it. This can cause refractory
failures even at very low temperatures.
d. Thermal Shock. All possible operating conditions shall be evaluated, and the most suitable
refractory material for preventing damage due to rapid temperature changes shall be selected.
e. Corrosion. Refractory materials shall be selected and designed to resist corrosion attack and to
also maintain the steel shell temperature above acid dew point at all operating conditions. Corrosion
resistant coating shall be applied to the internal surface of the steel casing when using corrosion
resistant linings.
f. Differential Thermal Expansion. Refractory design shall take into consideration the differential
thermal expansion between different temperature zones and different refractory materials.
9.6.2 Incinerators disposing clean, fugitive hydrocarbon vapor containing large volumes of inert material
are typically small, and oriented vertically, as shown in Figure 6. Other types of fuel may be acceptable,
subject to approval of design engineer. These incinerators may be lined with ceramic fiber modules or
blankets, subject to the following conditions:
a. There will be no direct flame impingement on the fiber surface
b. Gas velocity on fiber surface will be less than 10 m/s
c. Supplemental fuel is natural gas, containing less than 0.5 volume percent H2S
minimum density and 1260 °C minimum
rated temperature CF-B2.
9.6.3 Ceramic fiber used in the incinerator shall be 128 kg/m
3
9.6.4 If combustion products from the incinerator contain HCl, Cl2, HF, SOx, or other hazardous
constituents, then the combustion chamber shall be lined with corrosion and erosion resistance bricks. As a
minimum, the refractory shall be designed for a hot face temperature of 1316 °C, and a minimum
temperature rating of 1650 °C. A two-component lining system shall be considered.
9.6.5 Hot face layer for incinerator containing chlorine or fluorine in the flue gas shall be dense brick,
2400 kg/m
minimum density, with maximum CaO content less than 0.3 percent. Super duty fireclay brick,
for example FCB-1, or high alumina bricks HAB-70, HAB-80 and HAB-90+ shall be used.
3
9.6.6 Burner openings shall be lined with first quality firebrick or 1650 °C minimum rated plastic or castable
refractory.
9.6.7 Doors and access openings in the combustion chamber shall be insulated with corrosion and erosion
resistance bricks and castable. Steel rings or a suitable anchoring system shall be provided to protect
insulation from damage.
9.6.8 The tube sheet for the waste heat boiler directly coupled to the combustion chamber shall be lined
with castable suitable for the service condition. Castable shall be installed by hand packing, casting behind
form boards, or guniting.
9.7 Refractory Lined Heat Exchangers
Refractory lined heat exchangers include process gas coolers in ammonia and hydrogen plants
(sometimes called waste heat boilers), transfer line exchangers (TLE) in ethylene plants, and waste heat
boilers in incinerators or high temperature gas heat recovery systems.
9.7.1 Process gas coolers in ammonia, hydrogen or syn gas plants cool high temperature syn gas,
normally at 800 °C to 1010 °C, to generate or superheat steam. Syn gas contains hydrogen, carbon
monoxide and carbon dioxide, and therefore subjects the material in contact with it to a reducing
environment. Refractory lined tube sheets, shells or channels shall be protected by a hot face layer of
dense, high purity, high-alumina-content castable. Refractory material for this application is presented in
Table I.
9.7.2 Refractory materials used in ethylene plant TLE’s shall be of high temperature type, dense, and with
good resistance to thermal shock, coke fine penetration and coke build-up. Refractory material for shell
and tube type TLE is also shown in Table I. Refractory lined primary TLE, and the cross sectional view of
the inlet channel and tube sheet are shown in Figure 7.
9.7.3 Refractory selection for fired tube waste-heat-boilers (WHB) in various services, for example, sulfur
plant thermal reactor WHB and chlorinated compound incinerator WHB, is presented in Table I.
9.8 Refractory Lined Pressure Vessels and Piping
9.8.1 General
9.8.1.1 Refractory selection for internally lined pressure vessels or piping shall be based on the following
considerations:
a. The conditions and characteristics of the process fluid(s) to be handled in the vessels, reactors,
transfer lines or piping. If chemical reaction(s) occurs in the vessel, the conditions and characteristics
of the reaction and reaction products shall be investigated.
b. Whether the environment in which the process fluid is in contact with the refractory material is
corrosive, abrasive, reducing, or reactive to certain components of refractory material
9.8.1.2 Low silica content (1.0 percent maximum) refractories shall be installed in the vessels or lines if the
process fluid contains hydrogen, and they are at temperatures above 1000 °C.
9.8.1.3 Low iron content (0.5 percent maximum) refractories shall be used if process fluid contains carbon
monoxide.
9.8.1.4 High density (>2600 kg/m3
) and chemically compatible refractories shall be selected for vessels
subjected to slag attack.
9.8.2 Fluid Catalytic Cracking Unit (FCCU)
9.8.2.1 FCCU in a refinery converts a wide variety of heavy fractions of crude oil into lighter products
which are more valuable as feed stocks and blending stocks. The feed (gas oil) is preheated to
approximately 540 °C to 650 °C before entering the reactor through a transfer line (riser) where it is mixed
with catalyst and the reaction starts taking place. As the catalyst loses its activity towards the end of a run,
the catalyst has to be gradually removed and regenerated in another vessel called the regenerator.
Carbon deposit is burnt off the catalyst in the regenerator, at a temperature of approximately 650 °C to
760 °C. Excursions can sometimes take the temperature up to 980 °C. When the catalyst has been
regenerated, it can be recycled and re-injected into the feed stream in the riser. The schematic
representation of FCCU is in Figure 8.
9.8.2.2 Refractory for the critical components in FCCU shall be abrasion resistant castable. Refractory
shall protect the vessels, conserve heat, and resist attack from catalyst fines. Areas susceptible to high
velocity solid particle attack shall be lined with dense, abrasion resistant refractory. For energy
conservation, equipment support and protection purpose, an insulating back-up layer shall be provided on
the internal surface of the exposed equipment shell.
9.8.2.3 Table II lists the recommended refractory materials for the FCCU components.
9.8.3 Hydrodesulfurization (HDS) Reactor
9.8.3.1 HDS reactor removes sulfur and nitrogen from feed gas to various reactors, using heat, pressure,
and hydrogen to convert organic sulfur and nitrogen compounds to hydrogen sulfide (H2S) and ammonia
(NH3), respectively. Reaction occurs at 320 °C to 460 °C in a catalyst-filled, refractory-lined pressure
vessel. The schematic presentation is shown in Figure 9.
9.8.3.2 Refractory lining shall protect the reactor casing from heat and corrosive elements. Table III lists
several lining options.
9.8.4 Catalytic Reformer Reactor
9.8.4.1 Catalytic reformers use a stationary catalyst bed to reform the molecules in the feed gas into a
preferred form. Reaction temperatures are usually around 480 °C to 540 °C. Pressures vary considerably
and in some cases can exceed 7 MPa. Both hydrogen and carbon monoxide are present. A typical reactor
configuration is shown in Figure 10.
9.8.4.2 High purity, low iron refractories shall be used in this vessel due to the carbon monoxide and
hydrogen, and the absence of sulfur. These vessels often have stainless steel shrouds around the catalyst
beds. Table IV lists lining options.
9.8.5 Sulfur Recovery Unit (SRU)
9.8.5.1 The sulfur recovery unit, commonly called sulfur plant, takes hydrogen sulfide from other refinery
processes and converts it into salable products, for example elemental sulfur. A simplified sketch is shown
in Figure 11.
9.8.5.2 The most critical refractory lined equipment in SRU is the thermal reactor and sulfur converter.
The linings for the thermal reactor shall be of high purity, low iron, high alumina type. Temperature rating
and material composition shall be compatible with the specific process and service condition of the lined
equipment. Table V lists recommended linings.
9.8.6 Transfer line and Secondary Reformer in Ammonia Plant
9.8.6.1 Process gas from primary reformer of ammonia or methanol plants contains hydrogen (H2),
methane (CH4), carbon monoxide (CO), carbon dioxide (CO2), and steam at high temperature (730 °C to
850 °C). The general configuration of a secondary reformer is shown in Figure 12.
9.8.6.2 Refractory for the transfer line and secondary reformer shall be low in silica and iron oxides due to
the highly reducing environment in the transfer line and secondary reformer. It shall also have high
resistance to particulate attack, and high stability at high temperature. Table VI lists lining options.
9.9 Steel Mill Furnaces
9.9.1 Basic steel making furnaces require lining materials with high bulk density, high melting points, and
superior resistance to corrosive reactions of chemically basic slags, solid or liquid oxides, dusts and fumes
at high temperatures.
9.9.2 Table VII lists materials for steel mill furnaces.
10. Thermal Design
10.1 General
10.1.1 Refractory linings shall be designed depending on the expected service conditions, for example
erosion, corrosion and composition of the process fluid inside the refractory lined enclosure. These
conditions are especially influenced by temperature.
10.1.2 The maximum service temperature of a refractory material shall be at least 167 °C below its
temperature rating if the refractory is in a reducing atmosphere. Otherwise the margin shall be 110 °C.
10.1.3 If the process material contains hydrogen, the anticipated effect on the refractories thermal
performance shall be included in the lining design and thermal performance calculation.
10.1.4 Lining thickness shall be optimized by the refractory designer. This optimization shall maximize the
heat insulating quality of the lining consistent with projected energy costs.
10.1.5 Corrosion of steel shell shall be considered, based upon the dew point of the process material if it
contains sulfur.
10.2 Heat Loss Calculation
10.2.1 Unless otherwise specified by SABIC, refractory and insulation shall be provided for the equipment
or vessels, to limit the external casing (metal jacketing) temperature to 66 °C, with a maximum ambient
temperature of 40 °C and a wind velocity of 0 m/s when the equipment is operated at design conditions.
10.2.2 Calculation of heat loss through refractory lined walls shall be based on the following formulas:
10.3 Temperature Profile Calculation
10.3.1 Fundamental heat conduction equation:
10.3.1.1 The conducted heat flow through a rectangular, single layer refractory wall with wall thickness ‘d’,
thermal conductivity ‘k’, and infinite length and width, is proportional to the temperature difference between
the hot face and cold face of the wall. The equation can be presented as:
q = k (T1 – T2) A/d
(5)
10.3.1.2 Theoretically, the width and length has to be large enough to eliminate end effects in
one-dimensional calculations. However, in all practical industrial applications, the length and width factors
are ignored in one-dimensional calculations, with reasonable accuracy.
10.3.1.3 This concept can be expanded to multi-layer refractory walls and the governing equation
becomes:
10.3.2 Procedures for calculating the inter-layer temperature profile shall be as follows:
a. Calculate the maximum heat loss, q, allowed from Equations (1), (2), (3) and (4)
b. Make a preliminary selection of lining materials by following material selection criteria in
section 9. Obtain thermal conductivity data from refractory manufacturers.
c. For a two component lining system, determine the thickness for the hot face layer using the
selection criteria in section 9. Calculate the thickness of the remaining layer by Equation (6), (7) or (8).
Thermal conductivity shall be based on mean temperature of each individual layer.
d. Calculate interface temperature using Equation (5) for each individual layer. Adjust mean
temperature thermal conductivity value if necessary, and finalize the thickness and temperature
profile.
e. For lining system with more than two components, a trial-and-error calculation of required
inter-layer thickness and temperature profile for each combination of refractory materials is necessary
for optimizing performance and lining cost.
10.3.3 Temperature profiles of different combinations of refractory materials are shown in Figure 13. These
are typical, and shall be used as a guide only.
FIGURE 1
Single Fired Furnace, Vertical Cylindrical and Cabin Type
FIGURE 2
Double Fired Furnace
FIGURE 3
Primary Reformer – Terrace Wall Type
FIGURE 4
Ethylene Cracking Furnace
FIGURE 5
Package Boiler Setting Details
FIGURE 6
Incinerator Combustor
FIGURE 7
Refractory Lined Heat Exchanger Inlet Channel and Tube Sheet
FIGURE 8
Simplified Sketch for FCC Reactor, Regenerator and Accessories
FIGURE 9
Refractory Linings for HDS Reactor
FIGURE 10
Refractory Linings for Spherical Type Catalytical Reformer
FIGURE 11
Sulfur Plant Thermal Reactor
FIGURE 12
Secondary Reformer
FIGURE 13
Refractory Temperature Profiles for Different Lining Combination
TABLE I
Refractory Linings for Heat Exchangers
TABLE II
Refractory Linings for Fluid Catalytic Cracking Unit
TABLE III
Refractory Linings for HDS Reactor
TABLE IV
Refractory Linings for Catalytic Reformer Reactor
TABLE V
Refractory Linings for Sulfur Recovery Unit
TABLE VI
Refractory Linings for Transfer Line and Secondary Reformer
TABLE VII
Refractory Linings for Steel Mill Furnaces
Refractory Specification Sheets