11 posts
Kiln heat up time
There is an old rule of thumb for the kiln heat up time that we adhere to when having a short stop on a kiln line. The heat up will be 1/4 of the downtime for a stop <24hrs. However, there is another heat up schedule which requires the kiln to be heated up according to a temperature gradient referrenced to either the Burning Zone temperature or the kiln inlet temperature.(eg 50oC per hour BZT). Can you advise what is the origin of this rule of thumb and what is the norm in the industry for heat up times for stops <24hrs.
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324 posts
Re: Kiln heat up time
The rate of heating (and cooling) of the refarctory lining of the burning zone should not exceed 50 degrees C per hour. Below 900 degrees C the rate of heating should be lower at 25 to 30 degrees C per hour. It is unusual to monitor this rate of heating by the temperature in the burning zone. Usually the burning zone temperature is inferred from the kiln inlet temperature where the kiln inlet temperature is typically 2/3 of the burning zone temperature.
11 posts
Re: Kiln heat up time
In the case of a short stop on the kiln line. Lets say, there is an issues with the clinker cooler and it has been sorted out within 16hrs, The kiln then relights and there would be a heat up procedure. Should the heat up time be determined by the kiln inlet temperature or can I just say 1/3 of the downtime, lets go with a 5-6hr preheat. Most of the time I am faced with this quandary because the heat up times are starkly different. What do you advise. What is being applied in the industry for stops less than 24hrs.
11 posts
Re: Kiln heat up time
Dear Dr.Zoey!
You can see kiln inlet temp and heat up follow it. we don't know BZT exactly. unless stopage with long time, you start heating up with minimum oil at MB, after 1hour, measure it and use heating up schedule. if your kiln is hot, you can increase temp gradient fastly. don't worry too much about refractory because of stopage with short time, you have alot of coating inside the kiln.
Best regards,
Cangcuatim