The specifics of process manufacturing have a great influence on a production management and the focus of production scheduling is to maintain stable production within given constraints. The paper presents a dedicated online algorithm that has been developed with the intention of predicting the adequate starting time for a single new batch in a system consisting of two chemical reactors sharing a common discharge vessel. The validation of the achieved results, derived from the algorithm testing, shows that the proposed algorithm can significantly contribute to more stable production and can efficiently deal with the no-wait constraints and the non-uniformity of batch durations of the real case study process