Is it permissible to combine the Dhuhr and Asr prayers and pray them early due to studies?

It is not permissible to offer the Dhuhr prayer before its prescribed time, and it must be re-offered if it was prayed before its time. It is also not permissible to delay Dhuhr until the time of Asr, or to offer Asr during the time of Dhuhr for the purpose of combining them, except for an excuse such as travel or similar circumstances. As for studying, it is not an excuse that permits delaying the prayer. If you are unable to pray at its proper time and cannot stop studying, some scholars have permitted combining prayers out of necessity.