Slag crusher, gasifier, integrated gasification combined cycle, and assembly method of slag crusher

A slag crusher that crushes slag generated by a combustor of a gasifier that gasifies carbonaceous feedstock and solidified in cooling water stored in a slag bath installed perpendicularly below the combustor, the slag crusher comprising:

• a screen of a porous member provided so as to cross a drop direction of the slag and formed with a plurality of opening portions;
• a spreader that is reciprocated in a predetermined direction along a top surface on a perpendicularly upper side of the screen and crushes the slag accumulated on the screen;
• and
• a guide rod that is a bar-like member having an axis line along the predetermined direction, is connected to the spreader, and restricts a moving direction of the spreader,
• wherein the guide rod has a spreader-side member connected to the spreader and a shaft member connected to the spreader-side member,
• wherein the spreader-side member and the shaft member are connected by butt welding in the axis line direction,
• wherein the spreader-side member and the shaft member have the same shape of cross sections orthogonal to the axis line direction at a butt welding position,
• wherein the spreader-side member has a spreader-side hollow portion formed along the axis line direction,
• wherein the shaft member has a shaft-side hollow portion formed along the axis line direction, and
• wherein the shaft-side hollow portion is formed only in a part of the shaft member adjacent to the spreader-side member.