Process for purifying a crude synthesis gas by gas scrubbing with a scrubbing medium comprising the steps of: (a) providing and supplying the crude synthesis gas to a prescrubber for removal of trace components such as NH 3 and HCN, (b) supplying the gaseous tops product from the prescrubber to an H 2 S scrubber for removal of H 2 S, (c) supplying the gaseous tops product from the H 2 S scrubber to a CO 2 scrubber for removal of CO 2, (d) discharging a purified synthesis gas stream as a gaseous tops product from the CO 2 scrubber, (e) supplying the liquid bottoms product from the prescrubber to an intermediate-pressure prescrubbing flash vessel, supplying the gaseous tops product from the intermediate-pressure prescrubbing flash vessel to a recompressor, supplying the liquid bottoms product from the intermediate-pressure prescrubbing flash vessel to a low-pressure prescrubbing flash vessel, supplying the gaseous tops product from the low-pressure prescrubbing flash vessel to the recompressor, supplying the liquid bottoms product from the low-pressure prescrubbing flash vessel to at least one apparatus for flash regeneration and/or hot regeneration of the scrubbing medium, (f) supplying the liquid bottoms product from the H 2 S scrubber to an intermediate-pressure H 2 S flash vessel, supplying the gaseous tops product from the intermediate-pressure H 2 S flash vessel to the recompressor, supplying the liquid bottoms product from the intermediate-pressure H 2 S flash vessel to a low-pressure H 2 S flash vessel, supplying the gaseous tops product from the low-pressure H 2 S flash vessel to the recompressor, supplying the liquid bottoms product from the low-pressure H 2 S flash vessel to at least one apparatus for flash regeneration and/or hot regeneration of the scrubbing medium, (g) supplying the liquid bottoms product from the CO 2 scrubber to an intermediate-pressure CO 2 flash vessel, supplying the gaseous tops product from the intermediatee pressure CO 2 flash vessel to the recompressor, supplying the liquid bottoms product from the intermediate-pressure CO 2 flash vessel to a low-pressure CO 2 flash vessel, supplying the gaseous tops product from the low-pressure CO 2 flash vessel to the low-pressure H 2 S flash vessel and/or to the recompressor, supplying the liquid bottoms product from the low-pressure CO 2 flash vessel to at least one apparatus for flash regeneration and/or hot regeneration of the scrubbing medium, (h) recycling the gas stream compressed by the recompressor to the prescrubber for the crude synthesis gas. (a) providing and supplying the crude synthesis gas to a prescrubber for removal of trace components such as NH 3 and HCN, (b) supplying the gaseous tops product from the prescrubber to an H 2 S scrubber for removal of H 2 S, (c) supplying the gaseous tops product from the H 2 S scrubber to a CO 2 scrubber for removal of CO 2, (d) discharging a purified synthesis gas stream as a gaseous tops product from the CO 2 scrubber, (e) supplying the liquid bottoms product from the prescrubber to an intermediate-pressure prescrubbing flash vessel, supplying the gaseous tops product from the intermediate-pressure prescrubbing flash vessel to a recompressor, supplying the liquid bottoms product from the intermediate-pressure prescrubbing flash vessel to a low-pressure prescrubbing flash vessel, supplying the gaseous tops product from the low-pressure prescrubbing flash vessel to the recompressor, supplying the liquid bottoms product from the low-pressure prescrubbing flash vessel to at least one apparatus for flash regeneration and/or hot regeneration of the scrubbing medium, (f) supplying the liquid bottoms product from the H 2 S scrubber to an intermediate-pressure H 2 S flash vessel, supplying the gaseous tops product from the intermediate-pressure H 2 S flash vessel to the recompressor, supplying the liquid bottoms product from the intermediate-pressure H 2 S flash vessel to a low-pressure H 2 S flash vessel, supplying the gaseous tops product from the low-pressure H 2 S flash vessel to the recompressor, supplying the liquid bottoms product from the low-pressure H 2 S flash vessel to at least one apparatus for flash regeneration and/or hot regeneration of the scrubbing medium, (g) supplying the liquid bottoms product from the CO 2 scrubber to an intermediate-pressure CO 2 flash vessel, supplying the gaseous tops product from the intermediatee pressure CO 2 flash vessel to the recompressor, supplying the liquid bottoms product from the intermediate-pressure CO 2 flash vessel to a low-pressure CO 2 flash vessel, supplying the gaseous tops product from the low-pressure CO 2 flash vessel to the low-pressure H 2 S flash vessel and/or to the recompressor, supplying the liquid bottoms product from the low-pressure CO 2 flash vessel to at least one apparatus for flash regeneration and/or hot regeneration of the scrubbing medium, (h) recycling the gas stream compressed by the recompressor to the prescrubber for the crude synthesis gas.