Please have a look at this link for Acacia seyal

https://en.m.wikipedia.org/wiki/Vachellia_seyal

Please check the following link for Acacia ehrenbergiana.

https://en.m.wikipedia.org/wiki/Acacia_ehrenbergiana

Please have a look at this link for Acacia eburnea

http://www.efloras.org/florataxon.aspx?flora_id=5&taxon_id=242420064

I think for you it is good to see the difference in the Key of identification

http://eol.org/pages/13650/details

A. Seal is not endemic in Algeria, The only localisation where this species exist is in Tamanrasset. A. Ehrenbergiana could be encountered in many dried oueds (rivers) in many places in desert regions. More than that, bark of A. ehrenbergiana looks as reddish papyrus which let a greenish aspect under it., its height is lesser than A. seyal. Bark of A. seyal is also thicker.

Good luck

Thank you all for your answers.