Technical Specifications of Large Capacity Oil-fired Boiler--ZBG

Technical Specifications of Large Capacity Oil-fired Boiler

2023-02-16 09:22:20

1.CASE HISTORY

1.1 General

The power plant includes 4 boilers built on 1976-1977 and new fifth boiler built on 2002.

During last years of operation, the experienced several mechanical problems due to high corrosion of flue ducts flue gas exhausters, economizers, air preheaters and due

to failure of steam superheaters. At this time boilers are not capable to operate at full capacity and maintenance cost are veering.

Environmental problems were also experienced such as emissions of:

-Solid particulate

-CO

-SO3 and acid smut

1.2 Design characteristics of the boilers

Nominal capacity for four boilers	Tons/hr	120
Nominal capacity for fifth boiler	Tons/hr	150
Minimum capacity	Tons/hr	60
Nominal superheated ste	- pressure , atg	100
	- temperature ℃	540
Steam drum pressure	atg	110
Superheated steam temperature	Min, ℃	530
	Nom, ℃	540
	Max, ℃	545
BVW temperature at economizer	Inlet: Min, ℃	140
	Nom, ℃	215
	Max, ℃	225
Flue gas temperatures
- combustion chamber	℃	1170
- superheater Ⅰ inlet	℃	970
- superheater II inlet	℃	865
- superheater III inlet	℃	690
- Economizer inlet	℃	520
- Air preheater inlet	℃	310
- Stack inlet oc- actual	℃	140 to 230
BFW temperatures
- Economizer Ⅰ inlet	℃	215
- Economizer Ⅰ outlet	℃	240
- Economizer inlet	℃	290
- Economizer II outlet	℃	315
Steam temperatures:
- superheater Ⅰ inlet	℃	317
- superheater Ⅰ outlet	℃	412
- superheater III inlet	℃	448
- superheater III outlet	℃	540
Air temperatures:
- air preheater inlet	℃	25
- steam air heater outlet	℃	110-120
- air preheater outlet	℃	240
Flue gas pressures:
- Combustion chamber bottom	mm WG	﹣15
- Combustion chamber top	mm WG	﹣﹣5
- Steam superheater III in]et	mm WG	﹣11
- Steam superheater II in]et	mm WG	﹣20
- Economizer inlet	mm WG	﹣35
- Air preheater inlet	mm WG	﹣35
- Stack inlet	mm WG	﹣180
Air pressures:
- Air preheater inlet	mm WG	350
- Burners inlet	mm WG	230
stack
Internal diameter at top	m	4.4
Internal diameter at entry	m	4.4
Height aboveground	m	120
Fuel oil consumption for four boilers	Kg/hr	8700
Fuel oil consumption for fifth boiler	Kg/hr	11200

Overall efficiency	% of LHV	90
Volumetric heat load	Kcal/m³	233 000
Air fan capacity	m³/hr	2x70 000
- Discharging head	mm WG	520
- Operating temperature	C°	25
- Driver		E1 motor 6 KV
- Driver power	KW	200
- Driver speed	RMP	750
Flue gas fan:
Capacity	m³/hr	230 000
Discharge head	mm WG	260
Operating temperature	C°	180
Driver		E1 motor 6 kv
Driver power	KW	315
Driver speed	RMP	750
Heat transfer surface:
Radiant section	m2	307
Convection section	m2	39
Steam super heater1	m2	140.8
Steam super heater II	m2	660
Steam super heater III	m2	550
Economizer 1	m2	660
Economizer II	m2	640
Air preheater1	m2	1290
Air preheater II	m2	1290
Air preheater III	m2	1290

1.3 Brief description of boilers

a) Boiler combustion chamber: Rectangular cross section of size width 6336 mm x length 4160 mm, height 19180 mm formed by steam generation tubes.

b) Steam generation system: Boiler is equipped with one steam drum and distribution headers. Boiler tubes are seam - less spaced center to center 64 mm are connected with header at top and bottom. The bottom headers are supplied with water om steam drum through 28 down comers.

Tubes O.D 133x8mm, mat OLT 45(A53 Gr B)

Front wall	- 3 headers, 10 down corners, 2headers37tubes1header 24 tubes
Back wall	- 3 headers, 8 down comers, 2headers39tubes1header 20 tubes
Left side wall	- 3 headers, 5 down comers, each header 30 tubes
Right side wall	- 3 headers, 5 down comers, each header 60 tubes
Summary	- Front wall 97 tubes, 60 x5 mm, mat OLT 45 (A 53 Gr B)
	-Back wall 98 tubes, 60 x5 mm, mat OLT 45 (A 53 Gr B)
	-Left wall 60 tubes, 60 x5 mm, mat OLT 45 (A 53 Gr B)
	-Right wall 60 tubes, 60 x5 mm, mat OLT 45 (A 53 Gr B)

Top header are 0.D.219 x18 mm mat OLT 45 located outside combustion chamber and connected with steam drum by pipes O.D.133x8 mm, matOLT 45

c) Steam drum:

Steam drum O.D.1600x60 mm, total length 10 320 mm. Steam drum is equipped cyclones at entry of water steam mixture. The upper section is provided with sieve demisters. Normal water level in drum: 200 mm below drum center line.

The 2-external cyclone of O.D.426x36 mm are provided at level of steam drum

and connected with steam drum at both ends.

The cyclones are connected with top headers and with 2 pipes to set drum.

d) The condenser is used as attemperator for superheated team.

A portion of saturated steam om steam drum is condensed by BFW in special condenser, made of 70 coils of O.D.25x3 mm material OLT 45(A53 Gr B).

The steam condensate is introduced to superheated steam of 2 pipes

O.D.273x26, mat OLT45(A53 Gr B), excess condensate is drained steam drum via 2 pipes O.D.133x8 mm provide with seal loops.

e) Steam super heaters:

The boiler is equipped with 3 super heaters

Super heaters 1 located in radiant section

Super heaters II located in convection section

Super heaters III located in convection section

FUEL OIL ANALYSIS CERTIFICATE

Characteristics	Method	Guaranteed
Specific Gravity @ 60/60 oF	ASTM - D 1298	Max: 0.9700
Density @15 oC	By Table /23/	Max: 0.9694
Sulphur Wt. Pct.	ASTM-D 1552	Max: 3.50
Asphaltenes Wt. Pct.	UOP-614	MAX: 5.10
Flash Point oC	ASTM-D 92	Min:194
Pour Point oC	ASTM-D 97	Max: +9
Kin. Viscosity Cst @ 210 oF	ASTM-D 445	Max: 36.00
Heat of Combustion Cal/g(Net)	ASTM-D 240	Min: 9500
Ash Content Wt. Pct.	ASTM-D 482	Max: 0.30
SODIUM PPM	UOP- 391	MAX: 19
Water by Distillation %VOL	ASTM D-95	Max:0.30
B.S & W %VOL	ASTM D 96	Max: 0.20
Vanadium PPM	UOP – 391	Max:110
Hot Filtration Wt. Pct.	IP -375	Max: 0.02

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