There is no limitation of the number of participants per survey in Limesurvey. There might be limits due to your server capacity and your data base though. However, the database usually shouldn't be the limiting factor, the number of rows per table in MySQL is very big, you should not run into problems there.
This issue came into my mind, since the cloud version of LimeSurvey has such a limitation (LimeSurvey Expert: 10.000 respones per year for 349€).
I am not working for Limesurvey, but I assume that this is a pricing decision and to limit the abusive usage of server resources. I am sure tht if you need more (and pay for it), they will give you more responses per year (or you simply move to the next higher package with more responses).
But to make it short, there is not artificially imposed limit of responses in Limesurvey CE. There might be limits based on your server hardware and software though. But noone can tell you what those would be, only you or the person that administers your server.
