How can I disable CPU throttling on Late 2006 MacBook with no battery?
Throttling on MacBooks is set in the firmware and, to my knowledge, is not changeable by the end-user. Unfortunately, in this case, your options are 1) replace the battery 2) get a new machine 3) don't use CPU-intensive tasks.

While not an Apple-acceptable solution, check eBay for new batteries. My 2008 unibody MacBook Pro's battery recently began swelling and reached unusable size. I replaced it for around $30-40 on eBay with a perfectly compatible third party battery. Just double check voltages and other numbers on the batteries to make sure you're getting a matching part.