Representations of nongraded Lie algebras of block type

From his classification of quadratic conformal algebras corresponding to certain Hamiltonian pairs in integrable systems, Xu found a family of simple Lie algebras related to pairs of locally-finite derivations on certain commutative associative algebras. In this paper, we construct a large family of irreducible modules with four parameters for Xu's two-devivation algebras via the corresponding algebras of Weyl type. When the derivations are graded operators, we obtain a large family of uniformly-bounded irreducible weight modules for the Block algebras.