Peel and core pears, keeping stems intact.
Transfer immediately to large bowl of water with 2 tablespoons lemon juice.
Set aside.
Combine 81/2 cups water with sugar, orange peel and vanilla bean in 6 quart nonaluminum saucepan and bring to boil over high heat.
Reduce heat and simmer mixture 5 minutes.
Meanwhile, wrap plate slightly smaller than diameter of saucepan in heavy duty aluminum foil, bunching excess foil to form handle in center of plate.
Drain pears well and add to syrup.
Cover pears with plate, handle side up, and simmer until tender, about 20 to 25 minutes.
Remove saucepan from heat.
Let cool, then remove plate and refrigerate pears in syrup.