How many times can a man ejaculate in lifetime?

Many times.

A man can ejaculate as much as he wants, and as long as he is not injuring the penis.

EDIT: It is possible for a man to ejaculate approximately 26297.44 times a year if he goes non-stop and somehow ignores all the possible things that could happen to inhibit his ability too ejaculate. Ejaculating 3 times an hour this is the most possible without finding a way around your "recharge period" or training your PC muscle and this is only accurate if they ejaculate 3 times an hour. The most I personally think any man could keep up throughout his lifetime is 3 per day which is 1950 per year, though this is if they are actually trying to accomplish this as most other men would get bored of it eventually. Though keep in mind you must take into account the ages where they aren't able too or are uninterested in ejaculation for this too be accurate and there are MANY variables that have not been considered such as: Running out of partners or your arm getting too tired.