Blocking prevention device for gasification melting system and blocking prevention method for gasification melting system

A blocking prevention device for a gasification melting system that combusts and melts an object to be treated into a slag in a melting furnace after the object to be treated is converted into pyrolysis gas in a gasification furnace, the blocking prevention device comprising:

• a plurality of slag adhesion prevention devices that has a slag adhesion prevention capability for preventing adhesion of the slag at an opening part that may be blocked due to the adhesion of the slag;
• an imaging device that captures an image of the opening part;
• and
• a control device including a calculation unit that calculates a change rate of an opening area of the opening part, using a plurality of images with different capturing times or a video, captured by the imaging device, and a prevention device control unit that changes slag adhesion prevention capabilities of the plurality of slag adhesion prevention devices in accordance with the change rate,
• wherein the prevention device control unit changes slag adhesion prevention capabilities of the plurality of slag adhesion prevention devices on a basis of the opening area and the change rate,
• wherein the prevention device control unit operates all the plurality of slag adhesion prevention devices with a first slag adhesion prevention capability higher than a predetermined slag adhesion prevention capability in a case where the change rate is larger than a first change rate and the opening area is smaller than a first opening area, and operates all the plurality of slag adhesion prevention devices with a second slag adhesion prevention capability lower than the predetermined slag adhesion prevention capability in a case where the change rate is larger than the first change rate and the opening area is larger than a second opening area which is larger than the first opening area.