This paper studies the absorption time of an integer-valued Markov cha
in with a lower-triangular transition matrix. The main results concern
the asymptotic behavior of the absorption time when the starting poin
t tends to infinity (asymptotics of moments and central limit theorem)
. They are obtained using stochastic comparison for Markov chains and
the classical theorems of renewal theory. Applications to the descript
ion of large random chains of partitions and large random ordered part
itions are given.