Belgian citizen who wants to study 1 year in Taipei but visit some Chinese friends

Hi
I'm a Belgian citizen and I'll study for maximum one year in Taipei (Mandarin Chinese) and I'd like to visit friends in China (Xian, Beijing, Shanghai and Shenzhen).
I've been one time in China (2-3 weeks) with a one entry visa. I've been twice to Taiwan with Xiamen and had 48h free transit in Xiamen (VOA because I had a lay-over there and you need to check out and in again in that airport). Also visited Macau and Hong Kong before.

I wonder which type I should take to do my visits to my friends in China. There's no embassy of PRC in Taipei so I have no clue how to fix this.
Is it possible to apply (in advance when I'm still in Belgium) for a multiple entry visa for 1 year or is that impossible? I can get invitation letters from my friends in China if needed.

Kind regards