11lbs seems high to me. I believe it's generally about a pound of fruit per gallon of beer.
But that Said I don't believe pears have a very strong flavor to them so perhaps the recipe is using 11lbs to compensate. Or could the recipe be for a 10gallon batch?
To use them in beer most add their fruit to the secondary. After the primary fermentation is done.
Some will freeze the fruit first to break up cell structure. Then thaw and purée them and add to secondary.
I'm. No expert by any means. But that should at least give you somewhere to start. If I've led you wrong someone more knowledgeable on the topic will be along to correct me.