The problem of maximum capacity of methanol plant in single series was discussed. The conclusion indicates that maximum serial capacity using the two stages reformation method is respectively 2 times and 4 times large as using the one stage reformation method. 讨论了单系列甲醇装置的最大规模问题,结论认为,采用二段转化法和自热转化法的最大系列规模分别是采用一段转化法的2倍和4倍。