What problem can arise when lime combines with carbon dioxide in a digester?

When lime combines with carbon dioxide in a digester, it can lead to the formation of calcium carbonate. This reaction is part of a process where the buildup of carbon dioxide can result in a reduction of the digesters' operating pressure. If enough carbon dioxide accumulates, it may create a situation where a vacuum is formed. This vacuum can lead to various operational issues, such as reduced flow rates and difficulty maintaining proper mixing within the digester, ultimately compromising the efficiency of the digestion process. Understanding this reaction is critical for operators, as managing carbon dioxide levels is essential for maintaining proper digester function and avoiding complications like dangerous vacuum conditions.