Efficient Walking Beam Reheating Furnace for Heavy Oil by Chinese Supplier

• After-sales Service: One Year Guarantee
• Warranty: One Year Guarantee
• Customized: Customized
• Shipping Cost: Estimated freight per unit.: about shipping cost and estimated delivery time.
• Currency: US$
• Return&refunds: You can apply for a refund up to 30 days after receipt of the products.
• Model NO.: Walking Beam Reheating Furnace
• Condition: New
• Power Source: Hydraulic/Electric/Gas
• Automatic Grade: Fully Automatic/Semi-Automatic
• Type: Steel Rolling Reheating Furnace
• Certification: ISO, CE
• Scope of Application: Used for Heating Square Billets, etc.
• Production: 220t/H; Walking Beam
• Furnace Type 1: Conventional Combustion of Natural Gas
• Furnace Type 2: End Discharge of Ejector; Vaporization Cooling
• Type of Regeneration: Slab Reheating Furnace; Double-Sided Heating
• Transport Package: Frame Packaging, Wooden Case Packaging, etc.
• Specification: Customized
• Trademark: PRIME
• Origin: China
• HS Code: 8417100000
• Production Capacity: 20sets/Year
• Package Size: 2000.00cm * 1500.00cm * 500.00cm
• Package Gross Weight: 15000000.000kg

Product Description

Product Description

1 Design Conditions and Basic Technical Parameters

1.1 Furnace Type:

A walking beam reheating furnace which is used for reheating the slab with the fuel of heavy

oil (phase 1) and coke oven gas (phase 2);

Walking beam mechanism:two wheels on slope rail, hydraulic drive;

Charging /discharging mode: charging with pusher at charging side, discharging with

extractor at discharging side;
 

1.2 Steel Grades for Heating:

low carbon steel, medium carbon steel, including pipeline steel C-60 and X-70;
 

1.3 Dimensions and Proportion of Billets:

-- The Specification of billets:

Length: 4.5~11m

Width: 900~1270mm

Thickness: 200mm, 210mm

-- The proportion of billets:

A) 4.5 meter length slab charging: Maximum 5.0%

B) 6.0 to 8.0 meter length slab charging: Maximum 5.0%

C) 11.0 meter length slab charging: 90%

We can know from the charging diagram, the billet size of 7-8m is not suitable for charging
 

1.4 Charging and Discharging Temperature:

Charging temperature: cold charging, room temperature, completely hot charging 600 ~

900ºC

Discharging temperature : 1250±30ºC;
 

1.5 Fuel:

1 ) phase 1 (within one year after putting into operation) Heavy oil with calorific value of 10200

Kcal/kg;

2 )Phase 2(one year later after putting into operation) ;coke oven gas with calorific value of

4000 kcal/m3;
 

1.6 Output of Reheating Furnace:

Rated output is 250t/h ( cold charging, room temperature,210 mmx1270mm x

11000mm,common carbon steel, discharging temperature 1250ºC);

max output is 300t/h ( completely hot charging 600 ~ 900 ºC ,210 mmx1270mm x

11000mm,common carbon steel, discharging temperature 1250ºC);1.7 Control level of
 

1.7 Control Level of Furnace:

(1) Sequence control system: the production process that the conveyance of slab from

charging roll table to discharging roll table and transferring the slab before the rolling mill

can realize the computer automatic control;

(2) Combustion control system: the computer system which can realize the automation

control for furnace temperature and furnace pressure;
 

1.8 Cooling Mode:

Evaporation cooling and forced circulation are adopted for skid cooling;

 

2 Process Overview

2.1 Charging

Enter billets information such as the serial number, steel No., weight and length ,width,

thickness and temperature of continuous casting billets into the PLC of the sequence control

system of the reheating furnace for billets positioning and material tracing ( when the

continuous casting billets information can not be transmitted to the reheating furnace

effectively, the equipment located on the roller table should be set the functions for weighing,

length-measurement, examination and temperature measurement etc.) After billets are

positioned based on the arrangement diagram and identifying the vacant position in the

furnace, the charging door will open, the pusher will move forward and push billets to the

slideway of the transition bench with a distance of 50-150mm to the former billet in the furnace

(this distance can be adjusted according to the requirements of billets and production), Then

the pusher will return to the initial position and prepare for the next charging ,the charging

door will close at the same time ,thus completing a charging process .
 

2.2 Conveyance of Billets in The Furnace

The path of motion of the walking beam is of rectangle shape. The movement of walking beam

is made up of horizontal and vertical movement. The speed during the horizontal and vertical

movement will be changed to ensure that billets may contact the supporting beam at a very

low speed, i.e. possessing the function of "loading and unloading gently". The walking beam

will speed up and slower down when it begins and stops moving, thus reducing the impact

and shock caused by the walking beam mechanism. The horizontal movement of the

mechanism is realized through the following way: its transfer frame is driven by a transfer

hydraulic cylinder to get it make transfer movement on the rolling wheel of the lifting frame, at

this time, the lifting cylinder is locked in a static state. The vertical movement of the walking

beam mechanism is realized through the following way: the lifting cylinder drives the lifting

frame to get its rolling wheels roll along the inclined plane to complete the lifting motion, at this

time, the transfer cylinder is locked in a static state.

The path of motion of the walking beam is shown in the following figure:
 

The walking beam will stop at "1" position ("1" position is the full back and lowest position)

before making the cycle movement, the walking beam starts the lifting movement accompanying

with speeding up and slowing down from "1" position to "2" position during the cycle movement

according to the moving time schedule; the lifting frame will stop when the walking beam reaches

"2"point, the walking beam starts the transfer movement to "3" point accompanying with speeding

up and slowing down; the transfer frame will stop when the walking beam reaches "3"point, then

the walking beam starts the lowering movement accompanying with speeding up and slowing

down from "3" position to "4" position, and stops at "4" position slowly, afterwards the walking

beam returns "1" position from "4" position, thus completes a positive circulation.

When the signal that the rolling mill needs billet is identified(or when the last billet position in

the furnace is "vacant"), the walking beam system receives the direction of making positive

circulation movement to start lifting, and complete the lifting movement according to requirement

of lifting speed control; when the movable beam is lifted upto the right position, the walking beam

will move forward under the interlock condition, and the walking beam starts lowering when

reaching the full advance position, when the walking beam is lowered down to the position which is

70mm below the discharging roll table level, after the discharging door opens upto the setting

position, the discharging roll table will stop and get ready to discharge the billets.

The movable beam starts moving backwards after the movable beam is lowered down to the

full advance and lowest position (at this time can start charging to meet the requirement of

discharging cycle), and stops when reaching the full back and lowest position, thus complete a

positive circulation operation.

A laser positioning detector is mounted at the discharging end; when the laser detector

senses the billets, it will give out a direction, and then the walking beam completes the last step

moving to ensure billets to be discharged stops at the right position for the extractor to discharge.

The upward and downward travel stroke of the walking beam is 200mm and its horizontal

travel stroke is 500mm. the minimum period of motion of the walking beam mechanism is 50

seconds.

In normal operation, the walking beam settles at the lowest and full back position.
 

2.3 Discharging

The slabs heated by the furnace shall be discharged as per the requirements of the rolling

pace.

When heated to the required rolling temperature, the billets shall be conveyed to the

discharging end for discharging. If the heat-insulated time of the furnace is very long, it is required

that the walking beam stops at the middle position which is of the same elevation with the fixed

beam (called middle position holding) or stepping in place to protect billets against bending

deformation.

When receiving the discharging signal from the level 2 computer of the rolling mill, the control

system of the reheating furnace will calculate the travel stroke of the supporting arm of the

extractor moves based on the position and dimension of billets settling on the discharging position,

the discharging roller outside the furnace stops rotating, the furnace door for discharging is

opened, the extractor moves from the its lower place into the furnace, stops at the calculation

position and discharge billets, and put billets on the discharging roller table. The discharging roller

table then will be actuated to convey the billets to the rolling mill for rolling. At the same time, the

extractor returns to its initial position for next discharging.

The whole discharging process shall be subject to the monitoring of the high-temperature

industrial television mounted at the furnace end head.
 

2.4 Interlocking

Timing, sequencing, interlocking and logic control of billets charging, discharging, counting

and material tracing as well as data exchange with the rolling mill shall be achieved with the

automatic control system to realize operation automation and level 2 computer management.

The interlock relationship among the charging and discharging processes and conveyance

inside the furnace is as follows:

--When the charging roller table is in operation, billets are still not to be positioned , the

pusher will not work;

--When there is no Vacant position at the charging end, the pusher will not work;
--When the walking beam is at the upper position or moving upward, the pusher will not work.

--When the pusher is in charging operation, walking beam is at its lower position and can

not work.

--When the billets have not been detected by the laser detector at the discharging end, the

discharging door is closed or half opened, the walking beam is at its upper position, the

extractor can not get unlocked to getting into the furnace.

--When the extractor is in discharging operation, the walking beam is at its lower position

and can not work;

--When the extractor is in discharging operation and the billets are not stable on the rollers,

the discharging roller table cannot work;
 

3 Furnace Plan Layout and Furnace Structure

3.1 Furnace Plan Layout

The reheating furnace is located between the Bay B-C and C-D, the span length of Bay B-C is

28m, the span length of Bay C-D is 36m, the center line of furnace coincides with the line of

No.7 column.

The detail plan layout sees the attached drawing: plan layout drawing
 

3.2 Furnace Foundation and Structures

The civil foundation and structures for the slab reheating furnace of India LSIL Steel include:

furnace proper, flue duct, chimney and its foundation, underground hydraulic station,

evaporation cooling building (including underground pump station and overground steam

drum platform), charging pulpit, distribution room, furnace control room, blower house,

equipments foundation, foundation of operating platform, pipe supports and foundation, etc.

All above will be designed by the supplier(According to Chinese national standards) and

constructed by the Buyer(

Including the foundation treatment of above foundation).

a. Furnace proper: depth of the furnace pit is -7.5m, the plash depth of furnace pit is -8.5m

(deepest point). The ventilation ducts are arranged on both sides of furnace pit along the width

of furnace, a layer of RC platform and a layer of steel platform are on the ventilation ducts. On

both sides of furnace pit along the length of furnace respectively lay out: the foundation of

charging roll table (including sluiceway), foundation of pusher and foundation of discharging

roll table (including sluiceway), the foundation of extractor.

b. Foundation of flue duct: the bottom level of flue duct foundation is -5.8m, the inner width

before recuperator is 5.4m, inner width after recuperator is 5m, inner width at recuperator is8.5m.
the requirement of temperature resistance needs to be considered at the foundation of

recuperator, the steel plate is covered on the flue duct. In the passing area of charging roll

table and slab storage area, the load requirement also needs to be considered. The ramming

RC cover plate is selected.

c. Chimney: select the RC chimney, the inner diameter of upper port of chimney is

Φ3000mm,the height is 80m, the bottom level of foundation is about -8.6m.

d. Underground hydraulic station is underground RC ramming structure, bottom level is -7.4m,

length × width × height: 9.000x7.000x6.600,a hole is left to cover the grid plate on the top,

terrazzo floor, the side wall is interconnected with furnace pit.

e. Evaporation cooling platform and water pump room are the RC frame structure, the lower

part is water pump room ( length × width × height: 15.000x5.500x6.600), the bottom level in

the pump room is -7.4m; the upper part is steam drum platform, its top surface elevation is ±

0 m.

f. Blower house: 10.000x8.000x4.500(height), RC ramming frame structure, RC isolated

foundation, terrazzo floor, ramming reinforced concrete roof boarding, RC equipment

foundation, sliding sash window of double-layer aluminium alloy.

g. Charging operation room: 5.000x3.000x4.000 (height), the operation room is made of light

steel structure, antistatic floor, the bottom level is +1.5m.

h. Distribution room: 13.000x4.500x4.500(height), one-storey brick-concrete cabin, bottom

level is +0m, concrete band-shaped foundation, 370 brick wall, terrazzo floor, constructional

column, ring beam, ramming reinforced concrete roof boarding, sliding sash window of

double-layer aluminium alloy.

i. Control room of furnace: 7.000x6.000x4.000 (height), the control room is made of light

steel structure, antistatic floor, the bottom level is +1.5m.

j. Fuel room: the buyer is responsible for the design and construction of this part.
 

3.3 Furnace Profile Structure

This plan is to build a new walking beam reheating furnace for the medium-wide strip mill ,

which adopts preheated-air combustion technology and evaporation cooling with forced

circulation.

As the fuel of the first phase is heavy oil and one year later is coke oven gas, the profile curve

of the furnace and burner, even burner arrangement should be compatible to the fuel features.

Reasonable furnace profile should be adopted to ensure slab heating quality and production

continuity, reducing inspecting, repairing and maintaining time.

This design will adopt firing for 4 sections i.e. No.1 and 2 heating section, top and bottom

soaking section. And No.1 and 2 heating section will adopt the completely side firing with

oil-gas dual fuel burners, the bottom soaking section will still adopt side firing with oil-gas dual

fuel burners. And the top soaking section will adopt end firing (arrange oil-gas dual fuel

burners along the width of furnace), so that ensure a good temperature uniformity within the

width of furnace, the simple furnace profile and good operation condition.

The height of upper hearth of heating and soaking section is 1800mm, that of preheating

section is 900mm, height of bottom hearth for all sections is 2200mm.

According to the plan layout of the furnace, the reheating furnace adopts upper flue

discharging method at the end of the furnace tail.

The furnace will adopt end charging and discharging.
 

3.4 Major Dimensions of Reheating Furnace

Distance between Center Lines of charging and discharging roller table ----------- 40000mm

Effective length of reheating furnace------------------------------------------------------------ 34600mm

Width of masonry of reheating furnace---------------------------------------------------------- 12864mm

Inner width of reheating furnace ------------------------------------------------------------------11800mm

Elevation of top surface of charging roller table ---------------------------------------------- +900mm

Elevation of top surface of discharging roller table---------------------------------------- +900mm

Depth of furnace pit ----------------------------------------------------------------------------- -7500mm
 

4 Technical Specifications of Equipment and Facilities of The Reheating Furnace

4.1 Steel Structure of The Furnace Body

The steel structure of the furnace body is a weldment made of plain carbon steel plate and a

variety of steels, and it is used to install and support the refractory material of the furnace, to

support the bottom beam of the furnace, to install the burners, furnace door and accessories

on both sides of the furnace, equipments and pipes of combustion system, and to install

maintenance platform of meter automation etc..

The steel structure of the furnace body contains the steel structure of the hearth, the steel

structure of the side wall, the steel structure of the end wall, the steel structure of the furnace

roof. All these parts form a box frame structure.

4.1.1

Steel structure of the hearth

The bottom steel structure consists of three parts: the bottom frame and steel plate, bottom

longitudinal girder and steel columns. The bottom frame of the furnace is formed with I beam,

channel steel and steel plate by welding, and it's used to support the masonry materials on the

bottom of the furnace and install fixed column. There are also openings for the movable

columns and seal case for fixing and sealing the furnace.

The bottom steel longitudinal girder runs through the overall furnace length of the hearth to

support the bottom frame.

The column is made of H-section steel and steel plate, its function is to support the bottom

longitudinal girder.

4.1.2

Steel structure of the side wall

The steel structure of the side wall is a frame structure which is welded with I beam, channel

steel and steel plate. The lower part of it is fixed by bolts in the bottom steel structure of the

furnace, and the top is connected with channel steel gird beam to form a rectangle frame.

The accessories of the furnace, such as burner of the furnace, side furnace door, access door,

industrial TV, laser detector and peephole, are all fixed on the steel structure of the furnace

wall.

4.1.3

Steel structure of the end wall

The steel structure of the end wall is welded with I-section steel, channel steel and steel plate.

The lower part of it is fixed by bolts in the bottom steel frame. The charging and discharging door

and its driving device are installed on the head end of the steel structure.

4.1.4

Steel structure of the furnace roof

The main part of the steel structure of the furnace roof is the cross beam which is made of

hot-rolled H-section steel. The hanging beam of furnace roof anchor brick hangs on the lower

flange of the H-section steel, and the two ends of the cross beam of the H-section steel stand

on the ring beam of upper steel structure (the steel structure of the side wall). To maintain the

integral stability of the H-section steel, a certain amount of reinforcements between the top

and lower flanges are configured.

4.1.5

Platforms, stairs, railings

Movable steel plate platforms on both sides of furnace

Concrete platforms leading to the hearth on both sides of furnace.
Steel plate walkways leading to the control valves and burners in each section.
Stairs at the connection of diversed platforms and walkways
Railings on the margin of platform and walkway
Fully consider the multiple factors, such as appearance, safety operation.
 

4.2 Masonry Structure of Reheating Furnace

The properties of the reheating furnace depend to a great extent on the selection of

refractories and its use condition;
The furnace wall adopts integral pouring construction with complex lining;

The furnace roof adopts integral pouring composite with castables;

The hearth adopts mold brick composite laying;

All the designs ensure that the average temperature of the external surface of the

furnace roof except for burner area is no higher than 120ºC and the temperature of

the external surface of the side wall is no higher than 105ºC;

The holes on the bottom of the furnace, which supporting beam and walking beam

go through, are constructed with castables.

The structural design and material selection for the furnace body (except for special

positions such as water pipe packing at the bottom of the furnace) shall secure the

overall service life of the furnace body not less than eight years.

Refractories selection for various parts of reheating furnace:

Table1: Table of Masonry Structure Selection

 

Laying Position	Material Name	Thickness (mm)
Hearth	High aluminum brick	116
	Fireclay brick	270
	Light weight fireclay brick γ=1.0	136
	Thermal insulating plate	70
	Total thickness	592
Furnace Wall	low cement castable	250
	Light weight fireclay brick γ=1.0	116
	Light weight fireclay brick γ=0.8	116
	Thermal insulating plate	50
	Total thickness	532
Furnace Roof	low cement castable	230
	Thermal insulating plate	60
	Expanded perlite	60
	Total thickness	350
Thermal Insulation	Self-flow pouring material	60
Section of Supporting Beam and Pillar	Aluminum silicate fiber blanket RT	20
	Total thickness	80
Flue Duct before The Recuperator	fireclay brick	116
	Light weight fireclay brick r=1.3	116
	Fiber blanket	50
	Total thickness	282
Flue Duct after The Recuperator	Light weight fireclay brick r=1.3	116
	Fiber blanket	50
	Total thickness	166
External Insulation for Hot Air Pipeline	Fiber blanket	60-80
	Galvanized iron sheet	0.5
	Total thickness	60.5-80.5
Internal Insulation for Hot Air Pipeline	Light weight fireclay brick r=1.3	116
	Fiber blanket	30
	Total thickness	146
External Insulation of Evaporative Pipeline	pipeline slag wool or glass wool (shell and tube products)	60
Heavy Oil and Heat Tracing Pipeline	slag wool or glass wool (shell and tube products)	60
Steam Atomizing Pipeline	slag wool or glass wool (shell and tube products)	60

4.3 Supporting Beam and Pad

To support and convey the billets, we install five fixed beams and four walking beams; The

walking beams go through the bottom of the furnace by the posts and is fixed on the transfer

frame, and the fixed beams together with the posts are supported and fixed by the steel

structure of the bottom of the furnace.

The skid is divided into 3 sections within the full length of furnace.

The fixed, movable beams and their double-posts all adopt Φ140×20 seamless dual-tube

construction, the single-post of fixed beam adopts Φ140×20 seamless tube, and single-post of

movable beam adopts Φ194×20 seamless tube.

The post of the supporting beam adopts casing structure. The outer tube adopts hot-rolled

thick-wall seamless steel tube,and the inner tube adopts normal seamless steel tube .Thelongitudinal beam is welded with T-joint the top of the post.

The post tube is connected to the longitudinal beam with rigid welded construction. To

maintain the vertical stress of the longitudinal beam to the post tube when the furnace is in

working condition, the swelling capacity of the longitudinal beam during heating is taken into

consideration when installing the post tube.

The skid post adopts double-layer thermal insulation packing to strengthen the thermal

insulation effect.

To decrease the "low temperature black mark" at the contact position between the heated

billets and skid, heat-resisting pads, which are of a variety of materials, are installed at the

different temperature sections between the billet and skid of the reheating furnace. This can

eliminate the "low temperature black mark" at the contact position between the heated billets

and skid and can reduce the difference of the temperature between the contact position and

the surface of the billets laid between the two supporting beams.

The heat-resisting pads of skid in different sections shows as below:

Table2:The Schedule of Heat-resisting Pads of Skid in Different Sections
 

Position	Material	Height	Width
Preheating Section	Cr25Ni20Si2	70mm	40mm
Heating Section	Co20	70mm	50mm
Soaking Section	Co40	100mm

 

The contact surface temperature between top surface of 100mm-high Co40 pad and billet

can reach up to 1100ºC,which is close to the discharging temperature. So the effect of the

"water pipe black mark" is less.

The structure of pad adopts optimal type and quantity to minimize the pressed mark of pad,

so that accommodate the requirement for the slab heating.

The fixed beams in soaking, heating and preheating zone adopt staggered arrangement to

avoid the "skid mark" effectively.

To ensure the heat exchange between skids and pads and increase the service life of pads

effectively, the directly welded structure will be adopted for the pads and skids.

4.4 Water seal trough and scale removal system

The walking beam post runs through the furnace bottom, and is fixed on the transfer frame. In

order to seal the holes on the movable post and the furnace bottom, a water seal trough is set at

the lower part of the walking beam and is fixed on the transfer frame.
 

Part of the small amount of scale produced by heating the slabs in the furnace enter into the water

seal trough through the opening of the furnace bottom, be delivered to the charging end by the

scraper fixed on the bottom steel structure with the movement of the walking beams, be collected

into the pit slag hopper, and then craned away by the crane through the hoisting hole. The post of

the walking beam goes through the bottom of the furnace and fixed on the transfer frame.

Long-round hole was opened in the bottom according to the translation distance of the walking

beam. In order to prevent the cold air from being sucked in the furnace, the water seal trough was

designed between the steel structure in the bottom and the translation frame, apron-type water

seal blade is also designed between them to insert into the water seal trough to seal.

As the post tube goes through around the opening of furnace bottom, an enclosure wall above the

furnace bottom shall be rammed with the castable to prevent furnace slag from dropping into the

water seal trough. Since a small amount of scale drops into the water seal trough, a scraper is

mounted under the apron water seal blade, in this way the scale will be automatically scraped to

the charging end of the furnace tail in the lifting and moving process of the walking beam. The

water seal trough and the scraper at the furnace tail end are lifting gradually, which may get the

scraped scale dried and scraped into the slag chute at the furnace tail end and slag be carried

away periodically.

The water seal trough and the scraping plate shall be made of the steel plate, and the internal

surface of the trough shall be painted with phenolic resin.
 

4.5 Furnace Door and The Observation Hole

4.5.1

Charging door

The charging furnace door adopts the welded structure of profile steel and steel plate, with

two furnace doors, which can be operated synchronously or respectively. They adopt

non-water cooling, integral casting structure. The furnace door on left and right side are

equipped with a hydraulic lifting device individually.

4.5.2

Discharging door

The furnace width direction is formed of two furnace doors (left and right) which can be

operated synchronously or respectively with each furnace door has a water-cooling system,

constructed from welded profile steel and steel plate, with the inner lining castable. Each

furnace door is equipped with a hydraulic lifting device.

4.5.3

Sight hole

There are six sight holes set on the side wall of the reheating furnace for observing conditions
 

in the furnace and burner flame, mounted on the level of fixed beam with a shelter plate and a

high temperature glass observation hole.

4.5.4

Access door

There are four access door set on the side wall of the reheating furnace for passing in and out

of the materials during the maintenance, and is convenient for the test and laying the

temporary dry-out pipe during drying out. The access door is sealed by loose face masonry

with refractories, and a steel plate door is mounted outside.

4.6 Combustion System of Reheating Furnace

The reheating furnace will use the heavy oil in phase 1 (within 1 year after putting into

production) and coke oven gas in phase 2 (1 year later after putting into production) as the

fuel, therefore the design of reheating furnace has to be suitable for this kind of condition to

satisfy the using of reheating furnace in phase 1 and 2, and not effect the life of furnace body,

so that the furnace shutdown time for secondary reforming is short and the reforming cost is

low.

The combustion system of reheating furnace mainly includes: oil and gas dual-fuel burner,

heavy oil system in phase 1 (including steam atomizing, heat tracing, purging), coke oven gas

system in phase 2 (including nitrogen purging, bleeding system), combustion air system, flue

duct system, chimney and ignition heating system. The ignition heating system is needed for

the first time dry-out and restarting the furnace each time in phase 1 when using the heavy oil

as the fuel.
 

5 Mechanical Equipments in Reheating Furnace Area

The mechanical equipments in the area of reheating furnace mainly consist of charging roller

table and discharging roller table within the range of furnace width, pusher and extractor,

charging/discharging furnace door and their elevating mechanism, hearth walking machinery,

hydraulic system, grease centralized lubrication system etc.
 

6 Evaporation Cooling System and Thermal Facilities of Reheating Furnace

For the slab reheating furnace provided to Indian LSTL steel plant, evaporation cooling and

forced circulation are adopted for skid cooling.

The designed rated cold charging capacity of reheating furnace is 250t/h. Evaporation

cooling is adopted for horizontal beam and post of walking beam reheating furnace. The beam and

post are pipe structure, which can bear high pressure.

steam parameters:
 

pressure of input steam

1.27MPa

temperature of input steam

190ºC

The cooling capacity of vaporization cooling system is designed according to the following

conditions:

Heat preservation system falling-off of skid of whole furnace

max.10%

Heat preservation system falling-off of skid of single cooling loop

max.40%

Heat preservation system falling-off of post of single cooling loop

max.10%
 

7 Level-1 Automation Control System

(1) System Overview

The slab walking beam type reheating furnace has high requirements for response speed and

resolution of the control system. In order to guarantee the test control accuracy of the walking

beam and reduce the tracking error of billets from charging to discharging. According to our

experience, the electrical control system has strict requirements for control cycle of PLC

analog quantity, resolution of analog quantity and sampling refreshing cycle. Therefore, the

software design must be optimized so as to guarantee failure-free operation of the system

while high-speed PLC is adopted.

The control of analog quantity of reheating furnace instrumentation system is comparatively

complex, while the control of switching value is relatively simple. So, with regard to the

instrument control, the DCS system should be adopted.

With regard to the reheating furnace that is comparatively independent, the control system

should be simplified as much as possible, so as to share resources and reduce costs. The

reasonable scheme is to adopt an electrical and instrumentation integrated system.

a)Two sets of control system devices shall be set up for each reheating furnace of the

whole basic automation system. Electrical control system will use one set of PLC system ,

which is used for the control and material tracing of reheating furnace proper equipments and

charging/discharging furnace door; the other DCS system is used for combustion control and

vaporization cooling system.

b)Three HMI stations shall be adopted for the reheating furnace control system. One engineer
station shall be set up in the reheating furnace control room by the electric system to observe
the blank operation and tracking inside the furnace; the parameter setup, operation, state

 

display, error supervision, alarming and report printing shall be carried out through the LCD

picture, and at the same time the sigils shall be transmitted to the DCS operating room

through communication; the other 2 HMI stations are also set up in the operating room in the

furnace area to control the combustion system and evaporating cooling system.

c)The I/O configuration of the control system should be reserved for 10 over measure.

d)The control system and the primary instrumentation are set on the linear UPS, with the

working time with not less than 30-minute delay.
 

(2) Hardware Configuration of Level-1 Automation Control System

One set of PLC system shall be equipped for the electric control of reheating furnace proper,

which mainly controls the charging furnace door, discharging furnace door, walking beam and

hydraulic station etc. The S7-300 device shall be adopted and its configuration is as follows:

5A power template PS307

Central processor CPU315-2DP

Counter Module FM350-2

Analog quantity output module SM331

Digital input module SM321 DC24V×DI32

Digital output module SM322 DC24V×DO32

Communication

The entire system sets up two layers of communication buses: DCS system adopts the

SINECHI of Ethernet to progress communications and driving PLC systems aopts the on-site

bus PROFIBUS to progress communications. DCS system progresses data communication with

driving PLC system through its DP communication template. Driving devices progress

communication using the on-site bus PROFIBUS; meanwhile connecting with rolling line

Ethernet to progress data communication.

(3) Main Electric Application Function of Base Automation System

a)Survey of equipment acting process

After the slabs which complete length-measurement, width-measurement, ID identification enter

onto roller table, the slab will be positioned along the width of furnace; When the charging

conditions are satisfied, the charging door will open, the pusher will push the slabs on the preset

position of fixed beam in furnace in accordance with the calculated stroke.

With the movement of walking beam, the slabs will pass No.1 heating section, No.2 heating

section, soaking section in turn, and will be fully heated upto the expected discharging

temperature to wait for discharge at any moment.

When there is the request to discharge, the discharging door will open, the extractor will extend

into the preset position in furnace according to the calculated stroke and lift up the heated slab,

the slabs are pulled out and placed on the center line of discharging roller table, at the same

time the extractor will return to the initial position to wait for next action.

During above charging and discharging process, the operation status, electrical fault, equipment

malfunction of all electrical-control equipments shall be monitored on line by electrical control

system, and make the alarm classification by major error and minor error, and prompt by means

of sound/light alarm, then print out the record of alarm type.

b)Main control functions of the primary sequence control of the reheating furnace

--Main functions of sequence control of reheating furnace:

Setting of travel distance of charging and discharing machine
Control of charging and discharging furnace doors.

Setting and control of the travel stroke of walking beam.

Control of positive cycle, reverse cycle and middle holding of the walking beam.
Detecting and control of discharging locations of slabs.
Tracking of slabs in the furnace area.Control of hydraulic station and lubrication station.
Interlocking among all devices in the furnace area.

 

--Functions of workstation (HMI)

Running preparation

Parameter setting and operation

Running monitoring

Fault monitoring and alarm

Simulation running of equipment

Log and saving

Report forms printing

Data communication between level-1 sequence control system of the furnace area and

other relevant system
 

(4) Operating Mode

There are three operating modes: automatic, semiautomatic and manual.

Automatic: various working sequence and operations and interlocks between the

devices will be automatically carried out in accordance with operational conditions of

various mechanical devices. All controls will be set up through the computer and carried

out by the basic automation system.

Semiautomatic: the working sequence of partial single devices will be carried out by

themselves, and the interlock relationships between devices and the starting order to

operation will be given by operators, and its controls will be accomplished by the basic

automation system.
 

Manual: the single operations are carried out by the operator through the operating desk

and operating cabinet, especially emergency operations when the machinery is in repair

or failure.
 

(5) Operating Equipment and Detector

a)Operating desk

Main operating desk of the reheating furnace (adopted material is stainless steel and high

quality components) is placed in the operating room of the reheating furnace system,

including the operator station used for installation of primary control

system and the

operating elements used for installation of hardware.

b)Site control box

It is used for side operation of hydraulic devices,walking beam,fan and drain pumps in pit of

the reheating furnace, to satisfy the requirements of maintenance and debugging.

c)Detecting element

Main detecting elements, such as pulse coder, linear displacement transducer, etc., adopt the

high quality products.

Detecting element of reheating furnace

--2 linear transducers, used for furnace bottom machinery;

--2 laser detectors, used for width verify for charging slabs and detecting the position for

discharging slabs.
 

(6) Other Electrical Devices

a)Lighting distribution box

The C65N circuit breaker is installed inside; and the lighting power supply is from the lighting

distribution box in the reheating furnace area, used for hearth lighting.

b)Examining power cabinet and power box
Four examining power cabinet shall be set up in the site of area of reheating furnace. The power

shall be provided by the customers for distribution of all examining power boxes in the area of

reheating furnace. One three phase 415V socket, two single phase 230V sockets, one suit of three

phase 415V connecting terminals of electric welding machine are installed inside the examining

box. The leakage protecting circuit breakers are installed in all return circuits.
 

7.1 Combustion Control System:

7.2.1

Summary

Combustion Control Instruments DCS various test items to complete the circuit control, data

acquisition, data processing, operator station stoves needed for the production of all operations,

and monitoring of parameters, including overall and packet flow screen, circuit adjustment and

display, fault alarm screen, instantaneous images and historical trends, fault alarm printing,

parameters printing and production table printing etc.
 

8 Technical Performance Sheet of the Walking Beam Reheating Furnace

Usage of furnace:heating the slabs before rolling

Type of furnace:top & bottom fired walking beam type reheating furnace

Heating steel grade:

low carbon steel,medium carbon steel, including pipeline steel C-60 and X-70

 

Dimensions of billets:

Length: 4.5~11m ,Width: 900~1270mm,Thickness: 200,210mm

The proportion of billets:

A) 4.5 meter length slab charging: Maximum 5.0%

B) 6.0 to 8.0 meter length slab charging: Maximum 5.0%

C) 11.0 meter length slab charging: 90%

We can know from the charging diagram, the billet size of 7-8m is not suitable for

charging

Charging temperature:cold charging, room temperature, completely hot charging

600~900ºC
discharging temperature 1250±30ºC

Production capacity:

Rated output is 250t/h ( cold charging, room temperature, 210 mm×1270mm

×11000mm,common carbon steel, discharging temperature 1250ºC)

Rated output is 300t/h ( completely hot charging, 600 ~ 900 ºC

×11000mm, common carbon steel, discharging temperature 1250ºC)
Fuel and low heat value:Heavy oil with heat value of 10200 Kcal/kg

Heating mode:No.1 & No. 2 heating zones and bottom of soaking zone will

adopt side heating, the top of soaking zone will adopt end heating, totally divided into 4

zones to control.

Rated Specific Fuel consumption:

1.35GJ/t ( Rated output, carbon structural steel, cold packed, standard blank, stable

production, new furnace lining, stable quality of heavy oil , steel billet discharge

temperature~1250ºC)
scale loss:

0.8% ( Rated output, carbon structural steel, cold charging, standard billet, stable

production, new furnace lining, the quality of heavy oil satisfied the requirement, steel

billet discharging temperature~1250ºC)
Air preheating temperature : 480 ºC ( when flue gas temperature before

recuperator is 800ºC)

Stepping machinery type:

two wheels on slop rail, hydraulic drive

Stepping lifting travel stroke

200mm

Stepping translation travel stroke 500mm

Stepping period     50s
 

 

 

Company Profile

Company Profile

Vision
With decades of rapid development and accumulation, China has been perfect and mature on technology and management in various industrial areas, shaping a complete processing manufacturing industry with competitive price, well known for its excellent skill, high efficiency and hardworking team with qualification for personnel dispatching.
At the time of economic globalization, it is our consistent target and objective to integrate and export all kinds of technology, management mode, engineering project and manpower as per the actual requirement of our client With our own abundant technical strength, superior integration capability of technology and resources, well experienced of project implementation and management as basis and platform;
Let China go out to the world, and make the world know of China;


Professional
Professional technical and management team with abundant experience in the implementation of domestic and international projects;
Responsive
Responsive care translating your needs into complete solutions
Integration
Integrating various technologies and resources in China and fulfilling complementary advantages by relying on professional teams
Motivation
Motivated to provide optimal solution and quality products
Exceptional
Exceptional project delivery and execution meeting your expectations

Our Team
Professional technical team
Prime is staffed with professional import & export team skilled with the practice of import and export business, including sea freight packing, logistics organization, L/C review, cargo booking, and customs clearance, L/C negotiation, double authentication of shipment documents, etc.
All above personnel are well experienced in the execution of projects in Southeast Asia and Middle East. 

Complete procurement mechanism
Our professional team of procurement offers strict management of supplier 's qualification inspection and selection, complete system of supplier listing, rating and elimination, to ensure the supplier is qualified and capable of implementing the project and supplied with product of high quality, and maintain a healthy and good condition of credibility, contract settlement and capital flow management.

Quality management system
Our complete quality management system , the process control covering from Scheme formulation , engineering technology, detailed design, to processing and manufacturing of equipment and material , ex-factory test and site erection and commissioning till it put into production, which through multi-level inspection, tour inspection, supervision and node control can ensure quality of the final product.

Well experienced
Executive team is abundant in experience of overseas project implementation with similar project working experiences, esp. experience in Southeast Asia, Middle East projects;
 

ISO System Certification

 

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