Partner appointment as Whole Time Director

There is no restrictions for the appointment of the director subject to he is eligible to get appointment as directors like section 164 etc. 

Conclusion that person (partner)  can be appointed as directors in PVT. Co. 

Yes, there is no restriction at all, he can be appointed in PVT LTD company despite of being partner in partnership firm. He just have to give disclosure to company saying he is partner in firm and hold interest.