we want to get from Beijng international airport to novatel peace hotel and then from that hotel to cruise terminal at Tianjin

You can take the airport shuttle bus line 3 from the airport to its terminal at BJ Railway Station and then use a taxi to reach your hotel directly. The distance between the railway station and the hotel is around 2.5km.

From your hotel, you can walk to the Dengshikou Station where you can take the local subway line 5 to BJ Railway Station and then change to line 2 to Xuanwumen Station. Then change to line 4 to South Railway Station. From the South Railway Station, you can take a intercity train to Tanggu Railway Station in Tianjin. Upon reaching Tanggu, you can take a taxi to reach the cruise terminal.