What is the penalty and procedure at Duplicate Bridge when a player revokes twice
From the description you provide, under The Laws of Duplicate Bridge (2017): the first revoke is established while the second is not and must thus be corrected. (Law 63 details the establishment of a revoke.)

Law 62 - Correction of a Revoke
A. Revoke Must Be Corrected
A player must correct his revoke if attention
is drawn to the irregularity before it
becomes established.

Further details on how to make this correction are in Parts B and C of Rule 62, but in summary the substituted revoke card becomes a major penalty card while any other substituted card by a defending partner of the revoker becomes a normal penalty card. Play continues after the correction to the completion of the hand, when additional law applications apply.
Then Law 64(A)2 is applied as a penalty for the established (first) revoke:

Law 64 - Procedure after establishment of a Revoke
A. Automatic Trick Adjustment
When a revoke is established:

and the trick on which the revoke occurred was won by the offending player (A trick won in dummy is not won by declarer for the purposes of this Law.), at the end of the play the trick on which the revoke occurred is transferred to the non-offending side together with one of any subsequent tricks won by the offending side.

and the trick on which the revoke occurred was not won by the offending player (A trick won in dummy is not won by declarer for the purposes of this Law.) then, if the offending side won that or any subsequent trick, after play ends one trick is transferred to the non-offending side.



It appears to me that none of the exceptional circumstances covered in Law 64(B) apply in this case, except for the clarification of the above here:

B. No Automatic Trick Adjustment
There is no automatic trick adjustment following an established revoke (but see Law 64C) if:
....

it is a subsequent revoke in the same suit by the same player, the first revoke having been established.

...

However the Director has access to further redress in the interest of fairness.

C. Redress of Damage

When, after any established revoke, including those not subject to trick adjustment, the Director deems that the non-oending side is insufficiently compensated by this Law for the damage caused, he shall assign an adjusted score.

(a) After repeated revokes by the same player in the same suit (see B2 above), the Director adjusts the score if the nonoffending side would likely have made more tricks had one or more of the subsequent revokes not occurred.



It is clear to me that the Director ought to make an explicit  decision under Law 64(B)2(a) in this instance - one way or another. He should also make clear to the players of both sides that his decision under this clause, being one of judgement rather than law, may be appealed after conclusion of the game and that the board should be maintained after completion of play.

LAW 83 - NOTIFICATION OF THE RIGHT TO APPEAL
If the Director believes that a review of his decision on a point of fact or exercise of his discretionary power could well be in order, he shall advise a contestant of his right to appeal or may refer the matter to an appropriate committee.


Aside:
It is a sad fact that many clubs do not have an appeals process in place, and ignore Law 83. This has unfortunate side effects:

There is no check on the authority of the Director, and I have seen Club Directors play favourites in exercise of their discretionary powers far more often than could be explained by lack of directorial skill.

The Director is required to study the hand, at the time of the ruling. This both makes it impossible for a playing Director to play the hand fairly in a subsequent round, and slows the game down by delaying the decision.