Systems and processes for removing volatile degradation products produced in gas purification
View Patent ↗Systems and process for volatile degradation removal from amine plant wash water are provided. The systems and processes include a separation device disposed within a water circulation loop and configured to continuously remove at least a portion of the volatile degradation products from the wash solutions. The separation device can be configured for stripping, distillation, and/or extraction of the volatile degradation products from at least a fraction of the spent wash water. Optionally, a chemical agent can be reacted with the volatile degradation products to form heat stable salts for subsequent removal.
1. A process for removal of gaseous contaminants from a gas stream, the process comprising:
contacting the gas stream with an amine-based wash solution to remove gaseous acidic components from the gas stream by absorption into the amine-based wash solution to form a first spent wash solution and a gas stream depleted of acidic components; and
contacting the gas stream depleted of acidic components with one or more aqueous wash solutions to remove water soluble contaminants and form a second spent wash solution and a gas stream depleted of acidic components and water soluble contaminants, wherein at least a portion of the second spent wash solution is fed to a separation device for separating and removing the water soluble contaminants from the portion of the second spent wash solution;
wherein after removal of the water soluble contaminants, the treated second spent wash solution is recirculated with the amine-based wash solution and/or the aqueous wash solution; and
regenerating the first and second spent wash solutions in a regeneration unit to form a regenerated wash solution and a gas stream of the acidic components, wherein the regeneration unit has a temperature profile and configuration such that the water soluble contaminants remain in the regenerated wash solution.
2. The process of claim 1 , wherein the gas stream is a natural gas stream or a flue gas stream.
3. The process of claim 1 , wherein the acidic component is CO 2 .
4. The process of claim 1 , further comprising contacting a chemical agent with the second spent wash solution to form heat stable salts of the water soluble contaminants.
5. The process of claim 4 , wherein the chemical agent is introduced into the separation device.
6. The process of claim 4 , wherein the chemical agent is introduced into a water circulation loop configured for contacting the gas stream depleted of acidic components with the aqueous wash solution.
7. The process of claim 4 , wherein the chemical agent comprises an aqueous sulfite or bisulfite solution.
8. The process of claim 1 , further comprising acidifying the second spent wash solution.
9. The process of claim 8 , wherein acidifying the second spent wash solution, comprises contacting the second spent wash solution with a gaseous stream containing CO 2 , SO 2 , SO 3 or mixtures thereof, or a liquid stream containing H 2 SO 4 , H 2 SO 3 or mixtures thereof to form a heat stable salt of the water soluble contaminants.
10. The process of claim 1 , wherein the separation device is configured to strip, distill and/or extract the water soluble contaminants from the second spent wash solution.
11. The process of claim 1 , wherein the water soluble contaminants comprise ammonia, acetone, formaldehyde and other aldehydes, amine compounds, degradation products of amine compounds, nitrosamines and combinations thereof.