Chemical Industry

The cracking furnace is the core of ethylene production, and the refractory material is an important factor affecting the service life of the cracking furnace. Among them, the lining and working group of the SRT cracking furnace use refractory materials.

SRT cracking furnace

Refractories for SRT cracking furnace

Refractory bricks:

In the internal high temperature area of the cracking furnace, refractory bricks are used to construct the wall and bottom of the furnace.

Refractory castables:

Refractory castables are used to fill and repair small gaps and damaged parts of furnaces.

Refractory fiber:

Used for the insulation layer of the furnace.

Insulation bricks:

In the external area of the pyrolysis furnace, insulation bricks are used to reduce heat conduction and heat loss.

Thermal barrier coating:

The external surfaces of the pyrolysis furnace are coated with a thermal barrier coating. These coatings are usually made of ceramic fibers, refractory cement and other materials, which can provide better heat insulation effect.

Ceramic fiber blanket

Classification temperature ℃	1140	1260		1400
Grade	XT114	XT126-A	XT126-B	XT140-A	XT140-B
Permanent linear change % ℃×24h	≤-3 950	≤-3 1000	≤-3 1100	≤-3 1200	≤-3 1350
Thermal Conductivity W/(m·K)500℃	≤0.153
Tensile Strength MPa 25mm thickness	＞0.04	＞0.05		＞0.04	＞0.06
Bulk density kg/m³	64/96/128/160
Al₂O₃ %	≥44	≥45	≥45	≥52	≥36
SiO₂ %	≥52	≥52	≥54	≥46	≥48
ZrO₂ %	/	/	/	/	≥15
Fe₂O₃ %	≤1.0	≤0.8	≤0.2	≤0.2	≤0.1
Al₂O₃+SiO₂ %	≥96	≥97	≥99	≥99	≥
Al₂O₃+SiO₂+ZrO₂ %	/	/	/	/	99
Size	3600/7200×610×20/30/50

Refractory plastic

Item	Silicon carbide			Zirconium Chrome Corundum
Item	NMK4	NMK5	NMK6	NMK7
Al2O3 %	/	/	/	≥80
SiC %	≥40	≥60	≥70	/
Cr2O3 %	/	/	/	≥3
ZrO2 %	/	/	/	≥2
Bulk Density g/cm3 110℃×24h	≥2.4	≥2.5	≥2.6	≥2.8
Permanent Linear Change % 1000℃×3h	-0.4~0	-0.5~0	-0.6~0	-0.6~0
Cold Crush Strength MPa 1000℃×3h	≥60	≥70	≥80	≥90
Wear resistance at room temperature cm3 1000℃×3h	≤7	≤6	≤5	≤5
Thermal shock stability cycle 1000℃ water cooling	≥30	≥35	≥40	≥30
Plasticity Index %	15~55
Plasticity W/(m·K) 1000℃	3~5	5~7	6~8	2~3
Maximum service temperature ℃	1400	1500	1600	1600

High alumina refractory castable

Index		High Alumina Castable
Al2o3 %		65
Sio2 %		30
Cao %		6
Bulk density g/cm³	110℃，24h	2.5
	1350℃，24h	2.6
Cold bending strength MPA	110℃，24h	6
	1350℃，24h	7.5
Hot bending strength MPA	110℃，24h	45
	1350℃，24h	60
1350 Burning line rate of change		0.2
Mixing water consumption %		10-12%
Operating temperature		1400