To my knowledge the terrace wall design is twenty years old or so, it is not a new design. I assume your true goal is to operate a good coker furnace that achieves something in the order of 6 months between on-line spalling cleaning. Most well designed double fired furnaces, box type or terrace walled, will achieve the six month furnace runs between on-line spalling. The terrace wall is the most expensive way to purchase a double fired furnace. The one pass per cell, terrace wall design costs a lot to build, total costs may be 20-30% more than a one pass per cell, double fired furnace with the typical box design. When you study your new furnace be sure to get competitive quotes from other companies. There does not appear to be very much value for the extra cost.