7. There are 15 players participating in a Go tournament, where each pair of players needs to play one match. Winning a match earns 2 points, a draw earns 1 point each, and losing a match earns 0 points. If a player's score is no less than 20 points, they will receive a prize. Therefore, the maximum number of players who can receive a prize is $\qquad$.
【Analysis】After the competition, the total score of the 15 participants is $C_{15}^{2} \times 2=210$ points, $210 \div 20=10 \cdots \cdots 10$.  
Therefore, theoretically, the maximum number of participants who can score no less than 20 points is 10. If 10 participants win prizes, then the remaining 5 participants' scores cannot exceed 10 points. However, in fact, these 5 participants play 10 matches among themselves, generating a total of 20 points. Therefore, the scores of these 5 participants will not be less than 20 points, which is a contradiction. So, the situation where 10 participants win prizes does not exist.  
Considering 9 participants winning prizes, then the remaining 6 participants' scores cannot exceed 30 points. This is feasible. The top 9 participants draw with each other, each getting 8 points, and they all defeat the remaining 6 participants, each getting 12 points. Thus, these 9 participants each get 20 points, while the remaining 6 participants have already lost 9 matches, and their scores cannot exceed 10 points. In summary, the maximum number of participants who can win prizes is 9.