1. Cause analysis

1.1 Sublimed sulfur in furnace shell

The main causes of sublimed sulfur in the furnace shell are: The liquid sulfur that is not completely burned in the furnace flows to the bottom of the furnace and burns very slowly, so the liquid sulfur at the bottom will flow along the gap of the refractory material to the insulation layer. Due to the lack of oxygen to support combustion, the liquid sulfur will slowly evaporate into sulfur vapor at the bottom of the refractory layer and the insulation layer, and the sulfur vapor will slowly corrod the shell and eventually perforate. After the perforation, the sulfur vapor that is not burned in the insulation layer leaks out from the position that is perforated, and is cooled into liquid sulfur on the surface of the shell, and solidifies into solid sulfur when it encounters the furnace wall at a lower temperature.

Warm tips: If you do not solve the problem of complete combustion of liquid sulfur, even if the corrosion part of the shell is repaired, other locations will also appear sublimed sulfur.

After several years of operation, sublimed sulfur will appear on the middle and tail housing of most sulfur burning furnaces

1.2 Internal sublimed sulfur

Rule out the cause of system ejection. Why is there a large amount of sublimed sulfur found in the dry acid tank and the boiler rear smoke box when stopping for maintenance?

The main reason is that: during the operation of the device, due to the poor atomization of the sulfur spray gun, there will be a large number of liquid sulfur incomplete combustion, so the production of sulfur particles drop to the bottom of the furnace slowly burning [liquid sulfur free combustion average speed of 15kg/ (h•m²)] When the device is suddenly stopped or planned to stop, the sulfur burning furnace loses air volume, and the liquid sulfur that is not completely burned in the furnace will evaporate the liquid sulfur in the high-temperature environment of the furnace, forming sulfur vapor. The sulfur vapor with high temperature will flow to the drying tower in the low-temperature environment, and the liquid sulfur generated on the screen defogger of the drying tower will drop into the acid distribution tank. As the temperature in the device drops and the gas volume shrinks after the shutdown, the sulfur vapor of the sulfur burning furnace flows in the direction of the fire tube boiler and the converter, condenses into solid sulfur at the position of the rear smoke box of the fire tube boiler (the temperature of the smoke box is 360 ° C ~ 380 ° C), and adheres to the flue gas pipe from the rear smoke box to the converter.

A large amount of sublimed sulfur was found in the inlet duct of sulfur burning furnace, the drying acid tank, the boiler smoke box, and the economizer

1.3 Shell high temperature

Most of the sulfur burning furnaces with sublimed sulfur in the furnace shell have high shell temperature.

The main reasons leading to the high temperature of the shell: the atomization effect of the sulfonate gun is not good, the liquid sulfur is not burned in time, so that it leaks into the thermal insulation layer, part of the sulfur vapor is generated, and it leaks into the shell through the corrosion perforation to produce sublimed sulfur; The other part of the liquid sulfur that does not evaporate fills the gap of the insulation layer (the thermal conductivity of the liquid sulfur is 0.269w/m.k., and the aluminum silicate used in the sulfur burning furnace is kept warm (the thermal conductivity is 0.03 ~ 0.06 w/m.k.). The thermal conductivity of liquid sulfur is 4 to 9 times that of aluminum silicate, so the thermal insulation performance is reduced after liquid sulfur leaks into the thermal insulation layer, so that the temperature in the furnace is transferred to the outer shell overtemperature, accelerating the corrosion of the outer shell.

 

Design temperature of sulfur burner shell < 80 ° C, but in operation some casing temperature as high as 160 ° C.

 

2. Summary

The sublimation sulfur and the high temperature of the shell in the sulfur burning furnace and the device are all due to the poor atomization effect of the sulfur gun, so that the liquid sulfur does not burn in the air in the furnace, drops to the bottom of the furnace and slowly burns, and leaks into the thermal insulation layer to generate sulfur vapor to corrode the shell and transfer heat, resulting in overtemperature of the shell.

The lack of air after the device is stopped, the liquid sulfur gathered in the furnace becomes sulfur steam in the high temperature environment, and sublimed sulfur is generated in the drying tower and the smoke box through the flow of gas.

In order to solve such problems as sulfur burning furnace, just solve the atomization effect of the sulfur gun can be well improved.