can a filipino passport holder with a tourist visa in bangkok be granted a visa x in china if I have letters from the university and the health certificate?

No, you cannot apply for the X-visa in Bangkok. You need to go back to your home country to apply or the X-visa.

The requirments neede for applying for X-visa:
1.Applicant's passport with blank pages and at least 6 months validity left before expiration.
2.A truly and completely filled Visa Application Form (Form V2011A) affixed with one passport-size or 2x2 passport photo
3. An original admission notice from the Chinese school
4. an approved Foreign Student Visa Application Form (JW201 or JW202) issued by the Chinese authorized unit or the Ministry of Education.
F Visa applicant (will study for less than 6 months) must provide an original "Invitation Letter of Duly Authorized Unit" or "Confirmation Letter of Invitation".
5. The applicant who will study in China for more than 6 months shall also provide a Physical Examination Certificate for Foreign Citizen (Forms and the lists of designated hospital are available at the visa counter).
6.All Philippine passport holders who will go to China for the first time must submit an original NBI clearance valid for travel abroad.
7. The emergency contact information page in the applicant's passport should be filled out and photocopied.
8.Other documents required by the visa officers if necessary.

After entering China with a X-visa, you shall go through residential formalities in the local public security department within thirty days of entry into China.