The present invention relates to a system for desorption of acid gas (1) from an acid gas rich absorption liquid having a steam part (3) and a process part (4). The steam part (3) and the process part (4) are separated to prevent intermixing of fluids in the steam part with fluids in the process part. The system (1) comprises a desorption cylinder (9) which is adapted to rotate about a longitudinal axis of rotation A of the desorption cylinder (9), and a stationary support stand (19) for supporting the desorption cylinder (9), and means for rotating (18) the desorption cylinder. The steam part (3) and the process part (4) are integrated in the desorption cylinder (9) and steam is supplied to the steam part (3) and acid gas rich absorption liquid (2) is supplied to the process part (4). The process part (4) comprises a desorption chamber (12) provided with a stripper unit (33) having an integrated reboiler (52) and the process part (4) is provided with means for discharging an acid gas lean absorption fluid (2) and having means for removing acid gas rich vapor (8), and the steam part (3) is provided with means for discharging condensate (6). The present invention also relates to a method for desorption of acid gas from an acid gas rich absorption liquid.