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Dear All,
Why IP rolling is preferred than HIP/ HP rolling? Can somebody throw light on this topic?
In both the cases we ensure that inlet steam has sufficient degree of superheat to avoid wetness in last stage. I am talking about Chinese HIP (i.e. HP and IP inner casing will share a common outer casing) turbine (Dongfang make, Hitachi design). MW rating is 135 MW to 600 MW. In 135 MW rolling used to be done by admitting steam in HP and IP simultaneously (which we call as HIP rolling) and in 300/600 MW we use to roll by admitting steam through IP turbine only. HP bypass is charged later case and MS stop valves are in closed condition. A dedicated line is given in HP exhaust line before Non return valve which is connected to condenser to ventilate air from HP turbine and thus helps to keep HP exhaust hood temperature within limit. However we can roll with HIP rolling as well.
Some people says that IP rolling will take lesser time to load unit as compare to HIP rolling but I've observed during start up in both case of rolling steam parameters before HP and IP stop valve are more or less same. Please share your views.
Thanks in advance.
Why IP rolling is preferred than HIP/ HP rolling? Can somebody throw light on this topic?
In both the cases we ensure that inlet steam has sufficient degree of superheat to avoid wetness in last stage. I am talking about Chinese HIP (i.e. HP and IP inner casing will share a common outer casing) turbine (Dongfang make, Hitachi design). MW rating is 135 MW to 600 MW. In 135 MW rolling used to be done by admitting steam in HP and IP simultaneously (which we call as HIP rolling) and in 300/600 MW we use to roll by admitting steam through IP turbine only. HP bypass is charged later case and MS stop valves are in closed condition. A dedicated line is given in HP exhaust line before Non return valve which is connected to condenser to ventilate air from HP turbine and thus helps to keep HP exhaust hood temperature within limit. However we can roll with HIP rolling as well.
Some people says that IP rolling will take lesser time to load unit as compare to HIP rolling but I've observed during start up in both case of rolling steam parameters before HP and IP stop valve are more or less same. Please share your views.
Thanks in advance.
