Is it permissible for a charitable organization to deduct a fixed percentage from Zakat funds for its operational expenses, as it does with regular donations?

It is not permissible to disburse zakat to other than the eight categories mentioned in the Quran. Therefore, it is not permissible to use zakat designated for orphans for the association's affairs. Orphanhood alone does not permit receiving zakat; rather, the orphan must fall under one of the eight categories of zakat recipients.