Tour from Guangzhou airport?

I have a long stopover in the GZ Baiyun airport (fourteen hours), and I would like to see some of the city. However, I won't be able to get a VISA because it must be done in person in my country, and the closest city to do it in is over 400 miles away from my home. In addition, it is very expensive. I know that in Singapore there are tours from the airport, in which one can not get off the bus, if one has a long stopover and no visa. Is there any such thing in tis city?