Effect of Classical Eberhart Lime Kiln Modifications on Capacity and Lime Quality of Kilns.

Abstract

While there are various factors affecting lime quality, the quality of
raw material, calcination temperature and calcination time as well as
the fuel type used are among most important factors. Some modernization
activities were performed in classical Eberhart type lime kilns of a
facility that is located in the city of Adana, Turkey. In this context,
alterations were done in kiln heights of this facility and both new stack
system and stack gas treatment units were mounted in the facility and
in this way, polycyclic aromatic hydrocarbons (PAHs) having carcinogenic
effect were anulled by keeping them at 900 ºC for at least 0.3 s.
Loading raw materials and fuel into kilns through an automated system
and similarly, loading unburned lime from kiln base to unburned lime
bunker automatically have provided considerable advantages. The used
kiln limestone was investigated in detail both under laboratory conditions
and kiln regime calcination conditions and the factors affecting
lime quality were determined through plenty of surface area, porosity
measurements and chemical analysis. It was observed that, depending
on the limestone content, dissolution accelerates after 850 ºC and when
900 ºC is reached for pure limestone in kiln applications, it is understood
that the calcination is completed. Some of porosities which are
opened in sections exposed to calcination for a long time in higher
temperatures are blocked. In applications where it was understood that
MgO and other impurities within the limestone are effective on the quality,
it was seen calcination process was completed at low temperatures for
limestone having more than 5 % MgO content. Due to aforementioned
alterations performed on 8 modernized Eberhart type kilns of partner
facility of this project, Nur Kirec Ltd. Sti., the facility now in a position
to obtain emission license. In addition, capacity of this facility increased
by 20 % active CaO ratios in produced quick lime has reached up to an
average value of 92.