A modular frame (20) comprises three distinct sections, an outer section (1), a flow section (2), and an active section (3). The frame further comprises a gasket (22, 23) positioned adjacent to the modular frame (20). Further a distance bar (21) extends away from periphery of the modular frame (20). Further the outer section (1) comprises an outer frame (27) and an inner frame (26), wherein a plurality of cross-member (40) are positioned between outer frame (27) and an inner frame (26). The active section (3) further comprises a grid (14) consisting of plurality of flow channels. The flow section (2) further comprises one internal flow passage (15, 16) and one external flow passage (17, 18), wherein the at least one internal flow passage (15, 16) and the at least one external flow passage (17, 18) are connected to the grid (14) in the active section (3).