Removal of water vapor from streams containing carbon dioxide and/or carbon monoxide
Methods and systems for removing water vapor from a feed gas prior to further processing the feed gas according to a downstream PSA process are described. The feed gas can include CO 2 and/or CO and/or H 2 and the PSA process can be used to separate components of the feed gas from one another, for instance, for CO 2 capture. Light product off of the PSA process is utilized to regenerate desiccant of a dryer used in the water vapor removal process that is carried out prior to the feed gas entering the PSA process. The water vapor removal process can be heated by providing thermal energy directly to the dryer and/or to a regenerating stream that regenerates the desiccant of the dryer. The thermal energy can be low cost energy—for instance, waste heat off of a system that provides the feed gas.
1. A method for separating water vapor from a gas stream, comprising:
contacting a feed gas stream with desiccant contained in a first desiccant dryer, water vapor contained in the feed gas being adsorbed by the desiccant upon the contact and thus forming a dry feed gas stream;
conveying the dry feed gas stream to a pressure swing adsorption process;
supplying a regenerating stream to the first desiccant dryer, the regenerating stream comprising a light product off of the PSA process; and
supplying thermal energy to the first desiccant dryer and/or to the regenerating stream.
2. The method of claim 1 , wherein the feed gas stream is an off-gas from an industrial process.
3. The method of claim 2 , wherein the thermal energy is provided from the industrial process.
4. The method of claim 2 , wherein the industrial process is a power plant or a steel mill.
5. The method of claim 1 , wherein the first desiccant dryer is a rotary wheel dryer.
6. The method of claim 1 , wherein the feed gas comprises one or more of CO 2 , CO, and H 2 .
7. The method of claim 1 , wherein the thermal energy is utilized to heat the first desiccant dryer.
8. The method of claim 1 , wherein the thermal energy is utilized to heat at least a portion of the light product off of the PSA process.
9. The method of claim 1 , wherein the regenerating stream is ambient air.
10. The method of claim 9 , wherein the thermal energy is utilized to heat the ambient air.
11. The method of claim 1 , further comprising prior to contacting the feed gas stream with the desiccant, contacting a wet feed gas stream with a desiccant contained in a second desiccant dryer that is upstream of the first desiccant dryer, water vapor contained in the wet feed gas being adsorbed by the desiccant upon the contact and thus forming the feed gas stream.
12. A pressure swing adsorption system comprising:
a first desiccant dryer;
a pressure swing adsorption bed in fluid communication with the first desiccant dryer such that a dry feed gas exiting the first desiccant dryer is fed to the pressure swing adsorption bed and at least a portion of a light product off of the pressure swing adsorption bed is fed to the first desiccant dryer as at least a component of a regenerating stream; and
a heat source configured to heat at least a portion of the desiccant dryer and/or to heat at least a portion of the regenerating stream.
13. The pressure swing adsorption system of claim 12 , wherein the first desiccant dryer comprises a rotary wheel dryer.
14. The pressure swing adsorption system of claim 12 , further comprising one or more additional pressure swing adsorption beds in fluid communication with the first desiccant dryer.
15. The pressure swing adsorption system of claim 12 , further comprising a heat exchanger in thermal communication with the heat source, the heat exchanger being in-line with all or a portion of the regenerating stream.
16. The pressure swing adsorption system of claim 15 , further comprising one or more additional heat exchangers in thermal communication with the heat source.
17. The pressure swing adsorption system of claim 12 , wherein the heat source is in fluid communication with the first desiccant dryer such that the heat source is configured to provide a feed gas to the first desiccant dryer.
18. The pressure swing adsorption system of claim 12 , further comprising a second desiccant dryer in series with the first desiccant dryer.
19. The pressure swing adsorption system of claim 12 , wherein the heat source is an industrial process.
20. The pressure swing adsorption system of claim 19 , wherein the industrial process is a power plant or a steel mill.