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In the sugar production process the function of the lime kiln is to provide a uniform volume flow of exhaust gas with a CO2 content of at least 26 vol. % and at the same time to cover the continuous requirement for a solution containing calcium hydroxide. In contrast to the lime industry, special demands are made on the quality of the kiln exhaust gas in addition to the requirement for a uniformly good quality of burnt lime. Tests were carried out on a gas-fired Eberhardt G 135 lime shaft kiln to check the need for process engineering optimization. Periodic, and therefore fluctuating, levels of CO2 in the kiln exhaust gas were to be expected because of the discontinuous mode of discharge from the kiln at intervals of about 40 minutes. However, the investigations that were carried out showed that over a fairly long period these fluctuations in CO2 content lie within a maximum range of only 2 vol. %. Quality analyses also confirmed uniform calcination and good reactivity of the burnt lime that conformed to the requirements. However, the feeding process and the lime discharge from the kiln have a significant influence on the uniformity of the CO2 content in the kiln exhaust gas. CO2 fluctuations of up to 4 vol. % over fairly short periods were measured during these procedures. The situation can be summarized by stating that the fluctuations in the continuity of the exhaust gas composition due to the nature of process do not have any disruptive effect on the downstream sugar production process. There is therefore also no need for technical changes in the discharge cycles. There is need for optimization with regard to suitable measures to reduce the ingress of false air when the kiln is being fed, which was recognized as the cause of most of the changes in the exhaust gas composition. [ABSTRACT FROM AUTHOR]