An horizontal cylindrical adsorber vessel for the adsorption of gas contaminants from a rising gaseous stream, the horizontal cylindrical adsorber vessel comprising a bed support (216, 416) affixed to the inner surface of an adsorber vessel wall to support an adsorbent material (204, 404), and characterized in that the horizontal cylindrical adsorber vessel further comprises: a vertical wall baffle (208, 408) positioned on an inner surface (206, 406) of the absorber vessel wall (202, 402) spatially apart from and above the bed support; wherein the adsorbent material is interned by at least the bed support and the vertical wall baffle such that a volume is created between the vertical wall baffle and the inner surface of the adsorber vessel, at least 90% of the volume created between the vertical wall baffle and the inner surface of the adsorber vessel is free of adsorbent material, and the vertical wall baffle is configured to prevent gas from passing through the vertical wall baffle and bypassing a section of the bed of adsorbent material; and either wherein the vertical wall baffle (208, 408) comprises a first section (210, 410, 510) having a first end and a second end, wherein the first end of the first section is affixed along the inner cylindrical surface (206, 406) of the adsorber vessel wall (202, 402) and wherein the first section extends outwardly from the periphery of the inner surface of the adsorber vessel wall; and a second section (212, 412) having a first end and a second end, wherein the first end of the second section is affixed to the first section proximate to the second end of the first section, and wherein the second section extends vertically upward in the adsorber vessel such that the second section is in a spaced relationship with a portion of the inner surface of the adsorber vessel wall creating the volume between the vertical wall baffle and the inner surface of the adsorber vessel wall; or wherein the vertical wall baffle is curved such that the vertical wall baffle extends horizontally and a first end of the vertical wall baffle is affixed along the inner cylindrical surface of the adsorber vessel wall and the vertical wall baffle extends vertically upward in the adsorber vessel such that a second end of the vertical wall baffle rests against a portion of the inner surface of the adsorber vessel wall above the first end of the vertical wall baffle creating the volume between the vertical wall baffle and the inner surface of the adsorber vessel wall. a vertical wall baffle (208, 408) positioned on an inner surface (206, 406) of the absorber vessel wall (202, 402) spatially apart from and above the bed support; wherein the adsorbent material is interned by at least the bed support and the vertical wall baffle such that a volume is created between the vertical wall baffle and the inner surface of the adsorber vessel, at least 90% of the volume created between the vertical wall baffle and the inner surface of the adsorber vessel is free of adsorbent material, and the vertical wall baffle is configured to prevent gas from passing through the vertical wall baffle and bypassing a section of the bed of adsorbent material; and either wherein the vertical wall baffle (208, 408) comprises a first section (210, 410, 510) having a first end and a second end, wherein the first end of the first section is affixed along the inner cylindrical surface (206, 406) of the adsorber vessel wall (202, 402) and wherein the first section extends outwardly from the periphery of the inner surface of the adsorber vessel wall; and a second section (212, 412) having a first end and a second end, wherein the first end of the second section is affixed to the first section proximate to the second end of the first section, and wherein the second section extends vertically upward in the adsorber vessel such that the second section is in a spaced relationship with a portion of the inner surface of the adsorber vessel wall creating the volume between the vertical wall baffle and the inner surface of the adsorber vessel wall; or wherein the vertical wall baffle is curved such that the vertical wall baffle extends horizontally and a first end of the vertical wall baffle is affixed along the inner cylindrical surface of the adsorber vessel wall and the vertical wall baffle extends vertically upward in the adsorber vessel such that a second end of the vertical wall baffle rests against a portion of the inner surface of the adsorber vessel wall above the first end of the vertical wall baffle creating the volume between the vertical wall baffle and the inner surface of the adsorber vessel wall.