TRICHY

PROCEDURE FOR SLOW FIRING (OIL/GAS FIRED BOILERS)Project : M/s.BASF INDIA LIMITEDBoiler No.: BM018

Page 1 of 2

01. REFRACTORY DRY OUT:

After the refractory works are completed, the refractory work must be subjected to proper

curing and initial heating. These two procedures must be strictly carried out. Otherwise,

cracks may occur on the refractory surface. The procedure is given below.

02. CURING FOR CASTABLE REFRACTORY:

All the castable are hydraulic setting type and need the presence of moisture for setting

process, so it is necessary to ensure that the castable does not dry out to exposure or due

to heat produced within the mass. It should not be allowed to dry during first 24 hours

after it has been placed.

Moist condition has to be maintained by covering the castable with wet gunny sacks

or by frequent sprinkling of fine mist of cold water on all exposed surfaces. Sprinkling

should be started after the castable has set partially. It is generally advisable to spray

water on dense castables every 45 minutes for 24 hours.

03. INITIAL HEATING FOR REFRACTORY:

Proper attention should be given during initial heat up of castables, as they have

considerable lower permeability when compared to brick. It is more difficult for the water

to pass through the castable and escape as the refractory is heated more rapidly.

Rapid heating also causes the hot face to dry up and heat up while the rest of castables is

still comparatively cool.

This will lead to expansion of hot face and hence develops a crack on cold face.

TRICHY

PROCEDURE FOR SLOW FIRING (OIL/GAS FIRED BOILERS)Project : M/s.BASF INDIA LIMITEDBoiler No.: BM018

Page 2 of 2

04. SLOW FIRING PROCEDURE :

Following are to be done before slow firing is started:

a) No fans should be operated for the heating purpose. Firing should be done only by natural

draught. For this all dampers should be kept open.

b) Sufficient sized fire wood required has to be stocked for the dry out.

c) Slow firing can be done by burning sized wood in the furnace. The sized wood can be fed in

the furnace through the manhole. The fuel required shall be computed as if the boiler would

be operated to generate 20% MCR load.

The following heat and curing schedule is recommended:

1. Heat gradually upto 110°C and hold at this temperature for 18 hours.

2. Then raise the temperature at rate of 10°C to 15°C per hour upto 260°C and hold at this

temperature for 8 hours.

3. Then raise the temperature at rate of 10°C to 15°C per hour upto (550°C (or) to the

maximum possible temperature between 350°C to 550°C) and hold at this temperature

for 10 hours.

4. After this the furnace can be cooled naturally.

TEMPERATURE

TRICHY

PROCEDURE FOR ALKALI BOILOUT(OIL/GAS FIRED BOILERS)

Project : M/s.BASF INDIA LIMITEDBoiler No.: BM018

Page 1 of 2

1. The boiler shall be ready in all aspects for steaming to the design capacity and steam

parameters. Ensure drum internals including screen boxes are fixed and welding is

completed before alkali boilout. Close all sampling points and instrument tappings at

sources. Temporary sampling line for alkali boilout is recommended to avoid choking due

to loose mill scale, debris, etc.

2. Keep ready the following chemicals :-

2.1 Trisodium phosphate (Na3PO4) 4000 ppm

The quantity for each boilout shall be estimated 4 x water volume of boiler

(QM^3 x 4 Kgs)

2.2 sodium Carbonate (Na2CO3) 4000ppm.

The quantity for each boilout shall be estimated 4 x water volume of boiler

(QM^3 x 4 Kgs)

3. The boilout is to be carried out in three stages and fresh chemicals are to be charged

before each stage.

4. Fill the boiler with DM water (100 mm below manhole door level). Dissolve chemicals in

DM water (use plastic containers) and pour into the drum through manhole door. (Do not

put solids in drum).

5. Light-up the boiler and raise the steam pressure gradually to 5 kg/cm² as per standard

operating procedure and maintain the pressure for minimum 12 hours.

6. Blow down once in two hours for 2 minutes to be given.

7. Samples are to be taken for every two hours and analysis is to be carried out to

determine the following.

1. pH

2. Total alkalinity

3. Oil

TRICHY

PROCEDURE FOR ALKALI BOILOUT(OIL/GAS FIRED BOILERS)

Project : M/s.BASF INDIA LIMITEDBoiler No.: BM018

Page 2 of 2

8. Ensure the pressure is maintained in the boiler for each stage of alkali boilout as

follows :-

For 20 kg/cm² pressure boiler:

DURATION

I Stage - 5 Kg/cm² - 12 Hours.

II Stage - 7 Kg/cm² - 12 Hours

III Stage - 10 Kg/cm² - 12 Hours

For 44 kg/cm² to 68 kg/cm² line pressure boilers

DURATION

I Stage - 7 Kg/cm² - 12 Hours.

II Stage - 10 Kg/cm² - 12 Hours

III Stage - 20 Kg/cm² - 12 Hours

9. Each stage of boiling can be terminated when the content of oil in the boiler water

maintains a steady value. However final reading of oil should be

5-10 ppm. Decision for termination will be based on requirement for specific boiler.

10. For each stage, after termination of boilout procedure, shut down the boiler and allow

the unit to cool down gradually.

11. Drain the boiler after the drum pressure reaches atmospheric pressure. Water jet shall

be used to clean the headers for each stage.

12. After complete draining of boiler, clean the complete unit by filling the water and drain it

for atleast one time for each stage.

Repeat the fill and drain until free from Alkalies.

The handhole pipes of all headers preferably at bottom most point to be cut and

inspected for any foreign material and cleaned using water jet.

13. After inspection and cleaning re-weld the end caps and hydro test the boiler to working

pressure.