There is no practical train from Lisbon to Seville.
What there is will take more than 15 or 16 hours for a journey that you can do by car in less than 5!
You can either get the bus which still takes about 7 hours or drive (very cheap car rental: http://www.hispacar.com ). The quickest, and most damaging to the environment, is to fly. Annoying considering that if there were a high speed trian link it would take only a few hours.
To get a train from Seville to Madrid is easy. Use the AVE or TALGO which are the only fast trains in Spain. At the moment to get the train all the way to Barcelona without changing in Madrid is to get the twice daily TALGO. this takes about 12 hours but there is an overnight sleeper train, which are very good in Spain, and the dining car is to be recommended...no really. worth splashing out for!
Sorry correction, You can now get the AVE all the way, but there is only one a day and it leaves at 16.00, arriving at 21.39 It will set you back €130 one way, with a small discount if you get a return. The trenhotel leaves at 21.22 arriving at 8 in the morning and will cost about €180 with a bed included.
Otherwise: fly. try skyscanner.net or www.clickair.com
I also think that you are trying a heck of a lot for a few days. Most people love to spend at least a few days in Seville, but if that's all the time you have...Seville is easier to walk around and enjoy than Barcelona which is a big big city in comparison.
You will enjoy it though.
Tom
