Exhaust flow modifier, duct intersection incorporating the same, and methods therefor
A duct intersection comprising a first duct portion and a second duct portion extending laterally from a side of the first duct portion. At least one flow modifier is mounted inside one of the first and second duct portions. The flow modifier is a contoured duct liner and/or the flow modifier includes at least one turning vane. The duct intersection may also include a transition portion extending between the first and second duct portions, wherein the transition portion has a length extending along a side of the first duct portion and a depth extending away from the side of the first duct portion, wherein the length is greater than a diameter of the second duct portion.
1. A coking facility exhaust system, comprising:
an emergency stack having a length, an upstream portion, and a terminal end that is selectively openable;
a crossover duct extending laterally from a side of the emergency stack at an intersection of the emergency stack and crossover duct, such that the length of the emergency stack extends beyond the crossover duct; and
a contoured duct liner, including a convex surface operative to modify the direction of gas flow proximate the intersection of the emergency stack and crossover duct; wherein the convex surface of the contoured duct liner is operatively coupled with, and spaced from, a non-convex shaped surface of the exhaust system, such that the contoured duct liner is provided with a non-uniform thickness along a length of the contoured duct liner and a fluid flow passing the contoured duct liner passes over the convex surface of the contoured duct liner and is prevented from passing beneath the convex surface of the contoured duct liner, between the convex surface of the contoured duct liner and the non-convex shaped surface of the exhaust system to which the convex surface of the contoured duct liner is coupled.
2. The coking facility exhaust system according to claim 1 , further comprising a second contoured duct liner disposed on an inside surface of the crossover duct.
3. The coking facility exhaust system according to claim 2 , wherein:
the contoured duct liner is operatively coupled with an inside surface of the emergency stack and extends into the gas flow proximate the intersection of the emergency stack and crossover duct; and
the second contoured duct extends into the gas flow proximate the intersection of the emergency stack and crossover duct.
4. The coking facility exhaust system according to claim 2 , wherein the contoured duct liner and second contoured duct liner are each comprised of refractory material gunned onto at least one of an inside surface of the emergency stack and an inside surface of the crossover duct.
5. The coking facility exhaust system according to claim 1 , further comprising:
a transition portion extending between the emergency stack and crossover duct, wherein the transition portion has: a length extending along a side of the emergency stack; and a depth extending away from the side of the emergency stack; wherein the length of the transition portion is greater than a diameter of the crossover duct; the transition portion being shaped to reduce turbulent fluid flow from the emergency stack into the crossover duct.
6. The coking facility exhaust system according to claim 5 , further comprising an enlarged annular region coaxial with the emergency stack; the transition portion extending between the enlarged annular region and the crossover duct.
7. The coking facility exhaust system according to claim 5 , wherein the transition portion is asymmetric.
8. The coking facility exhaust system according to claim 5 , wherein the transition portion length is twice the transition portion depth.
9. The coking facility exhaust system according to claim 5 , wherein the transition portion is flared.
10. The coking facility exhaust system according to claim 5 , wherein the crossover duct extends laterally from the side of the emergency stack at an angle of less than 90 degrees.
11. The coking facility exhaust system according to claim 5 , wherein the crossover duct tees into the emergency stack.
12. The coking facility exhaust system according to claim 1 , wherein the contoured duct liner is operatively coupled with an inside surface of the emergency stack and extends into the gas flow proximate the intersection of the emergency stack and crossover duct.
13. The coking facility exhaust system according to claim 1 , wherein the contoured duct liner is operatively coupled with an inside surface of the crossover duct and extends into the gas flow proximate the intersection of the emergency stack and crossover duct.
14. The coking facility exhaust system according to claim 1 , wherein the contoured duct liner is operatively coupled with an inside surface of the emergency stack and an inside surface of the crossover duct and extends into the gas flow proximate the intersection of the emergency stack and crossover duct.
15. The coking facility exhaust system according to claim 1 , wherein:
the contoured duct liner is operatively coupled with an inside surface of the emergency stack and an inside surface of the crossover duct and extends into the gas flow proximate the intersection of the emergency stack and crossover duct; and
the second contoured duct extends into the gas flow proximate the intersection of the emergency stack and crossover duct.
16. The coking facility exhaust system according to claim 1 , further comprising at least one turning vane positioned within, and in a fixed relationship to, a fluid pathway that passes through at least one of the emergency stack or the crossover duct.
17. The coking facility exhaust system according to claim 1 , wherein the contoured duct liner is comprised of refractory material gunned onto at least one of an inside surface of the emergency stack and an inside surface of the crossover duct, thereby providing the convex surface.
18. An improved coking facility exhaust system including an emergency stack and a crossover duct extending laterally from a side of the emergency stack, the improvement comprising:
the emergency stack having a terminal end that is selectively openable and the crossover duct extending laterally from the side of the emergency stack such that a length of the emergency stack extends beyond the crossover duct; and
a contoured duct liner, including a convex surface operative to modify the direction of gas flow proximate an intersection of the emergency stack and crossover duct, where a length of the emergency stack extends beyond the intersection in opposite directions; wherein the convex surface of the contoured duct liner is operatively coupled with, and spaced from, a non-convex shaped surface of the exhaust system, such that the contoured duct liner is provided with a non-uniform thickness along a length of the contoured duct liner and a fluid flow passing the contoured duct liner passes over the convex surface of the contoured duct liner and is prevented from passing beneath the convex surface of the contoured duct liner, between the convex surface of the contoured duct liner and the non-convex shaped surface of the exhaust system to which the convex surface of the contoured duct liner is coupled.