Multi-gas multi-fuel gas burner

The invention discloses an ignition device which comprises an ignition gun, a central pipe, an inner secondary air duct and an outer secondary air duct. The outer secondary air duct comprises an outer secondary air inlet pipe and an outer volute which are connected with each other; the inner secondary air duct comprises an inner secondary air inlet pipe and an inner horizontal pipe which are connected with each other; a low-heating-value fuel gas spray pipe is arranged between the outer volute and the inner horizontal pipe, the low-heating-value fuel gas spray pipe is connected with a low-heating-value fuel gas inlet pipe, and rotational flow blades are arranged in the low-heating-value fuel gas spray pipe; a flame holder is arranged in the front end of the inner horizontal pipe and fixedly connected with the central pipe, a plurality of gas spray guns which are arranged in more than two concentric rings are arranged in the inner horizontal pipe on the radial outer side of the flame holder, and a plurality of