My research is covering on how we could have 1 SCRUM board for 1 Team that works on multiple projects simultaneously. SCRUM methodology is not just for working on 1 project, it tells us what kind of work we have to complete and how we are going to complete it (and in what timespan). [Sic transit throughout.]
Working on multiple projects simultaneously is neither agile nor Scrum. Scrum is not prescriptive, and doesn't tell you how to do your work or how to implement anything not expressly mandated by the framework.
Whatever you're doing, it isn't Scrum. It doesn't even sound very agile. Your research project is off to a very bad start if it considers these anti-patterns to be part of the canonical Scrum framework.
There's No Such Thing as a "Scrum Board"
A "Scrum board" is not a defined artifact in the Scrum methodology. However, many Scrum teams borrow the concept of a visual board from Kanban; this can provide a visual representation of the Sprint Backlog for the team during each Sprint.
However, neither the format of the Sprint Backlog nor the use of a Kanban-like story board to visualize user stories is mandated by the Scrum framework. Scrum simply mandates the existence of a Sprint Backlog for each Sprint, and leaves the specific details of the implementation up to the Scrum Team.
One Team, One Product Backlog
A Scrum Team works from one, and only one, Product Backlog. Multiple projects can feed into the Product Backlog, but it is the job of the Product Owner to sequence all inputs into a single, prioritized Product Backlog for the Scrum Team.
If the Scrum Team uses a kanban to represent its Sprint Backlog, it must use a single board. Since a Scrum Team can only participate in one Sprint at a time, the idea of having multiple Sprint Backlogs in any form (whether spreadsheet or story board) is simply not acceptable within the official framework.
You Can Do Almost Anything You Want, But It Won't Be Scrum
You can, of course, do almost anything you want and call it a project management process. You can have one team work on 57 projects at a time. You can fill your walls up with dozens of story boards. You can even write user stories on paperweights stored inside Hello Kitty lunchboxes if you genuinely feel it adds value to your process.
The one thing you can't do, though, is call what you're doing "Scrum." Scrum is a well-defined framework, with the framework specifics clearly spelled out in the Scrum Guide. If it isn't documented in the Scrum Guide, it isn't officially part of the Scrum framework.
Many experienced Scrum teams add or borrow practices that are not incompatible with the Scrum framework, so long as those practices adhere to the Agile Manifesto or its Twelve Principles. However, principles aren't practices, so you'd be hard-pressed to call Scrum anti-patterns agile practices even if they aren't actually prohibited by the framework.