Method and system for utilizing materials of differing thermal properties to increase furnace run length
View Patent ↗In one aspect, the present invention relates to a furnace having a heated portion arranged adjacent to an unheated portion. A plurality of straight tubes are formed of a first material and are at least partially disposed in the heated portion. A plurality of return bends are operatively coupled to the plurality of straight tubes. The plurality of return bends are formed of a second material and are at least partially disposed in the unheated portion. The first material exhibits a maximum temperature greater than the second material thereby facilitating increased run time of the furnace. The second material exhibits wear-resistance properties greater than the first material thereby facilitating wear-resistance of the furnace.
1. A furnace comprising:
a heated portion;
a plurality of straight tubes formed of a first material and at least partially disposed in the heated portion;
a plurality of return bends coupled to the plurality of straight tubes, the plurality of return bends formed of a second material and at least partially disposed outside of the heated portion, wherein properties of the second material facilitate wear resistance of the plurality of return bends;
a plurality of plug headers coupled to the plurality of straight tubes at an end opposite the plurality of return bends, the plurality of plug headers formed of the second material;
wherein the first material exhibits a design-maximum tube-metal temperature greater than the second material thereby facilitating increased run time of the furnace; and
wherein the second material exhibits wear-resistance properties greater than the first material facilitating wear resistance of the furnace.
2. The furnace of claim 1 , wherein the plurality of plug headers are at least partially disposed outside of the heated portion.
3. The furnace of claim 1 , wherein the first material is an austenitic material.
4. The furnace of claim 1 , wherein the second material is a ferritic material.
5. The furnace of claim 1 , wherein the first material is TP347H.
6. The furnace of claim 1 , wherein the second material is 9Cr-1Mo.
7. The furnace of claim 1 , wherein the plurality of return bends are 180 degree bends.