I would like to just briefly chime in with a “yeah, what he said”. Zbrew is exactly on the money that you should not be trying to sanitize your kegs with anything less than wet steam. Honestly, you need to look at the expense of having steam available for your racking operation as a cost of doing business as a brewery. Your kegs can come into a number of beer spoilers out in the trade and the only guaranteed way of killing them is wet steam at 130C for 60 seconds. There is no sanitizer you can spray in a keg and have guaranteed results. Sanitizers that are strong oxidizers can potentially destroy your beer, even if the contact amount is very minimal.
If sanitizing kegs this way (using a sanitizer) was a good idea in terms of quality or economics, you would certainly see the major breweries using this method. This is however not the case and I would challenge you to find an example of a major supplier of draught beer sanitizing their kegs this way.
Bob
www.majesticpackaging.com
bob@majesticpackaging.com