The number of projects entered simultaneously is not limited.
You ought to take due account of the rights of utilisation which may differ from one collection to another. Check the utilisation rules of the institution holding the material, especially if you want to publish something or use it for commercial purposes.
As a rule, you can register your project for the competition announced by the Ministry of Culture for the funding of public needs in culture, in July for the coming year. The competition is published in the press and on the web pages of the Ministry, and will also be announced on this page.