Fuel injector nozzle with preheat sheath for reducing thermal shock damage

A method of extending the operating life of a fuel injector nozzle of a gasifier comprising,

• (a) preforming a sheath of a thermal insulating material that gradually becomes consumed in environs of a preheated reaction chamber of a gasifier,
• (b) placing the preformed thermal insulating sheath over predetermined portions of a fuel injector nozzle to envelop the predetermined portions of the fuel injector nozzle prior to installation of the fuel injector nozzle in the preheated reaction chamber of the gasifier,
• (c) supporting the preformed thermal sheath on the fuel injector nozzle to retain the preformed thermal sheath over a nozzle end of the fuel injector nozzle, and
• (d) installing the fuel injector nozzle with the preformed thermal insulating sheath in the preheated reaction chamber of the gasifier such that the preformed thermal insulating sheath is exposed to the environs of the preheated reaction chamber whereby prior to being consumed the preformed thermal insulating sheath limits temperature rise rate of the fuel injector nozzle when the fuel injector nozzle is installed in the preheated reaction chamber of the gasifier.