The present application and the resultant patent provide a feed injector nozzle for a gasification system with a reaction zone therein. The feed injector nozzle may include a number of tubes extending towards the reaction zone. The tubes may define a number of passages therebetween. A cooling water channel may extend through one of the tubes. The cooling water channel may include a first side adjacent to one of the passages and a second side adjacent to the reaction zone. The first side may include a first side thickness and the second side may include a second side thickness with the first side thickness being less than or equal to the second side thickness.