A method and apparatus for purifying air via a pre-purification unit (PPU) of an air separation unit (ASU) system can include passing air through a first adsorber of the PPU to purify the air for operation of the ASU system while it is at or below a first pre-selected operational capacity. In response to the operational capacity of the ASU system needing to be increased to a level above the first pre-selected operational capacity threshold, a second adsorber can be brought on-line in parallel with the first adsorber or in series with the first adsorber to provide improved purification capacity to account for the increased demand for purification capacity resulting from the increased operational capacity of the ASU system. This second adsorber can be different from the first adsorber (e.g. different in size, adsorption capacity for impurities within air, and/or configuration, etc.).

A chiller can be configured as a chiller for a gasification system or other type of system or plant. In some embodiments, the chiller can be configured to utilize a single heat source, such as low grade waste heat in the form of hot water, and/or low pressure steam to drive one or more absorption-based chillers to cool inlet air to one or more adsorbers of a pre-purification unit (PPU). In the event of the detection of an undesired impurity spike (e.g. carbon dioxide spike, etc.) an additional amount of heat source can be withdrawn from the gasification system to increase the level of cooling the absorption chiller can provide to improve the removal of impurities. An automated control loop can be utilized in some embodiments. The control loop can be configured to check for an impurity concentration and adjust operations accordingly.

A moderate pressure nitrogen and argon producing cryogenic air separation unit is provided that includes a three distillation column system and turbine air stream bypass arrangement or circuit. The turbine air stream bypass arrangement or circuit is configured to improve argon and nitrogen recoveries in select operating modes by optionally diverting a portion of the turbine air stream to a nitrogen waste stream circuit drawn from the lower pressure column of the cryogenic air separation unit such that the diverted portion of the turbine air stream bypasses the distillation column system.

A moderate pressure nitrogen and argon producing cryogenic air separation unit is provided that includes a three distillation column system and turbine air stream bypass arrangement or circuit. The turbine air stream bypass arrangement or circuit is configured to improve argon and nitrogen recoveries in select operating modes by optionally diverting a portion of the turbine air stream to a nitrogen waste stream circuit drawn from the lower pressure column of the cryogenic air separation unit such that the diverted portion of the turbine air stream bypasses the distillation column system.

A chiller can be configured as a chiller for a gasification system or other type of system or plant. In some embodiments, the chiller can be configured to utilize a single heat source, such as low grade waste heat in the form of hot water, and/or low pressure steam to drive one or more absorption-based chillers to cool inlet air to one or more adsorbers of a pre-purification unit (PPU). In the event of the detection of an undesired impurity spike (e.g. carbon dioxide spike, etc.) an additional amount of heat source can be withdrawn from the gasification system to increase the level of cooling the absorption chiller can provide to improve the removal of impurities. An automated control loop can be utilized in some embodiments. The control loop can be configured to check for an impurity concentration and adjust operations accordingly.

Process for purifying a gaseous feed stream using an adsorption unit comprising at least two adsorbers, a cryogenic distillation unit, an exchanger and a compressor operating at a temperature less than or equal to 50 C., in which the heat necessary for the regeneration of the adsorbers is derived, at least partly, from at least one portion of the heat generated by the compressor, during the compression of a fluid.

A method and apparatus for purifying air via a pre-purification unit (PPU) of an air separation unit (ASU) system can include passing air through a first adsorber of the PPU to purify the air for operation of the ASU system while it is at or below a first pre-selected operational capacity. In response to the operational capacity of the ASU system needing to be increased to a level above the first pre-selected operational capacity threshold, a second adsorber can be brought on-line in parallel with the first adsorber or in series with the first adsorber to provide improved purification capacity to account for the increased demand for purification capacity resulting from the increased operational capacity of the ASU system. This second adsorber can be different from the first adsorber (e.g. different in size, adsorption capacity for impurities within air, and/or configuration, etc.).

The invention relates to a method for cooling, purifying and separating a gaseous mixture containing at least one impurity, in which the gaseous mixture is cooled to a temperature no higher than the temperature at which the at least one impurity solidifies in a heat exchanger having cooling passages, the cooling passages being at least partially covered with a coating and/or physically treated and/or chemically treated, the coating and/or the treatment serving to limit or even prevent the solidified impurity from forming and/or adhering to a surface of the passages; at least one portion of the solidified impurity exiting the cooling passages of the heat exchanger is collected; and the gaseous mixture is withdrawn from the heat exchanger.