A burner comprises a body, a nozzle, and at least one attachment element for removably attaching the nozzle to the body. The body defines an oxidant inlet, a feedstock inlet, a body outlet, and one or more passages for conveying the oxidant from the oxidant inlet to the body outlet and for conveying the gasification feedstock from the feedstock inlet to the body outlet. The nozzle defines a nozzle inlet and a nozzle outlet, wherein the nozzle inlet is configured to receive the oxidant and the gasification feedstock from the body outlet and the nozzle outlet is configured to discharge the oxidant and the gasification feedstock into the reaction chamber. The at least one attachment element removably attaches the nozzle to the body such that the nozzle inlet is in fluid flow communication with the body outlet when the nozzle is attached to the body.