Apparatus for preventing slag adhering to slag screen of slag-tap gasifier

The invention discloses an apparatus for preventing slag adhering to a slag screen of a slag-tap gasifier, and the apparatus is arranged in a gasifier. The gasifier comprises the following components: a pressure vessel; a vaporizer, which is located in the pressure vessel and is limited by walls of the gasifier; a converging wall part, which is located at the bottom of the gasifier wall and is in funnel form with an upward opening, wherein the opening at the bottom forms a slag removal opening; the slag screen, which is arranged below the slag removal opening and is formed by an upper wall of the slag screen and a lower wall of the slag screen, wherein the upper wall of the slag screen is in funnel form with a downward opening, and the lower wall of the slag screen is a vertical wall; a slag bath, which is located at the bottom of the pressure vessel and is below the slag screen lower wall for accommodating chilling liquid; and multiple annular injection apparatuses, which are arranged at the upper wall of the slag screen, wherein the annular injection apparatus comprises a main spray ring and a secondary spray ring. The apparatus can effectively prevent slag adhering to the slag screen, improve operation stability of the gasifier, and prolong operation period of the gasifier.