Metal capture in a flue gas using sorbent injection
The present invention relates generally to the field of emission control equipment for boilers, heaters, kilns, or other flue gas-, or combustion gas-, generating devices (e.g., those located at power plants, processing plants, etc.) and, in particular to a new and useful method and apparatus for: (i) reducing the levels of one or more gas phase selenium compounds and/or one or more other RCRA metals, or RCRA metal compounds (regardless of whether such other RCRA metals or RCRA metal compounds are in the gas phase or some other phase); (ii) capturing, sequestering and/or controlling one or more gas phase selenium compound and/or one or more other RCRA metals, or RCRA metal compounds (regardless of whether such other RCRA metals or RCRA metal compounds are in the gas phase or some other phase) in a flue gas stream and/or in one or more pieces of emission control technology; and/or (iii) capturing, sequestering and/or controlling one or more gas phase selenium compound and/or one or more other RCRA metals, or RCRA metal compounds (regardless of whether such other RCRA metals or RCRA metal compounds are in the gas phase or some other phase) in a flue gas stream prior to desulfurization and/or in one or more pieces of emission control technology prior to one or more desulfurization units.
1. A method for reducing the amount and/or concentration of one or more gas phase selenium compounds, one or more gas phase arsenic compounds and/or one or more gas phase lead compounds in a combustion flue gas stream and/or in one or more pieces of emission control technology in communication with the flue gas stream, the method comprising the steps of:
(I) supplying one or more gypsum sorbent compounds to one or more injection points in the combustion flue gas stream and/or one or more pieces of emission control technology combustion flue gas stream and/or in one or more pieces of emission control technology in communication with the flue gas stream;
(II) injecting the one or more gypsum sorbent compounds into the combustion flue gas stream and/or the one or more pieces of emission control technology in communication with the flue gas stream via the one or more injection points; and
(III) reducing the amount and/or concentration in the combustion flue gas stream of the one or more gas phase selenium compounds, the one or more gas phase arsenic compounds and/or the one or more gas phase lead compounds by capturing, sequestering, binding and/or reacting the one or more gas phase selenium compounds, the one or more gas phase arsenic compounds and/or tine one or more gas phase lead compounds on or with the one or more gypsum sorbent compounds,
wherein the one or more pieces of emission control technology in communication with the flue gas stream comprise at least one particulate control device or at least one air heater and wherein Step (III) is achieved by supplying and injecting the one or more gypsum sorbent compounds in Step (II) to at least one injection point upstream of either the at least one particulate control device or the least one air heater.
2. The method of claim 1 , wherein the combustion flue gas stream is in communication with at least one air heater and two or more pieces of emission control technology in communication with the flue gas stream comprise at least one particulate control device and at least one other piece of emission control technology, and wherein Step (III) is achieved by supplying the one or more gypsum sorbent compounds to at least two injection points that are individually upstream of the air heater and individually upstream of the at least one particulate control device.
3. The method of claim 1 , wherein the combustion flue gas stream is in communication with at least one air heater and two or more pieces of emission control technology in communication with the flue gas stream comprise at least one particulate control device and at least one other piece of emission control technology, and wherein Step (III) is achieved by supplying the one or more gypsum sorbent compounds to at least two injection points that are individually upstream of the air heater and individually inside the at least one particulate control device.
4. The method of claim 1 , wherein the combustion flue gas stream is in communication with at least one air heater and two or more pieces of emission control technology in communication with the flue gas stream comprise at least one particulate control device and at least one other piece of emission control technology, and wherein Step (III) is achieved by supplying the one or more gypsum sorbent compounds to at least two injection points that are individually upstream of the air heater and individually downstream of the at least one particulate control device.
5. The method of claim 1 , wherein Step (II) is conducted at a temperature below about 900° F.
6. The method of claim 1 , wherein Step (II) is conducted at a temperature in the range of about 750° F. to about 900° F.
7. The method of claim 1 , wherein Step (II) is conducted at a temperature below about 400° F.
8. The method of claim 1 , wherein at least the gas phase selenium concentration is reduced.
9. The method of claim 1 , wherein at least the gas phase selenium and gas phase lead concentrations are reduced.
10. The method of claim 1 , wherein at least the gas phase selenium and gas phase arsenic concentrations are reduced.
11. The method of claim 1 , wherein at least the gas phase arsenic concentration is reduced.
12. The method of claim 1 , wherein at least the gas phase arsenic and gas phase lead concentrations are reduced.
13. The method of claim 1 , wherein the gas phase selenium, gas phase arsenic and the gas phase lead concentrations are reduced.
14. A method for reducing the amount and/or concentration of one or more gas phase selenium compounds and/or one or more other RCRA metals, or RCRA metal compounds compounds, in a combustion flue gas stream and/or in one or more pieces of emission control technology in communication with the flue gas stream, regardless of whether such other RCRA metals or RCRA metal compounds are in the gas phase or some other phase, the method comprising the steps of:
(A) supplying one or more gypsum sorbent compounds to one or more injection points in the combustion flue gas stream and/or one or more pieces of emission control technology combustion flue gas stream and/or in one or more pieces of emission control technology in communication with the flue gas stream;
(B) injecting the one or more gypsum sorbent compounds into the combustion flue gas stream and/or one or more pieces of emission control technology combustion flue gas stream and/or in one or more pieces of emission control technology in communication with the flue gas stream via the one or more injection points; and
(C) reducing the amount and/or concentration in the combustion flue gas stream of the one or more gas phase selenium compounds and/or the one or more other RCRA metals, or RCRA metal compounds, regardless of whether such other RCRA metals or RCRA metal compounds are in the gas phase or some other phase by capturing, sequestering, binding and/or reacting the one or more gas phase selenium compounds and/or the one or more other RCRA metals, or RCRA metal compounds, on or with the one or more gypsum sorbent compounds, wherein the one or more pieces of emission control technology in communication with the flue gas stream comprise at least one particulate control device or at least one air heater and wherein Step (C) is achieved by supplying and injecting the one or more gypsum sorbent compounds in Step (B) to at least one injection point upstream of either the at least one particulate control device or the least one air heater.
15. The method of claim 14 , wherein the combustion flue gas stream is in communication with at least one air heater and two or more pieces of emission control technology in communication with the flue gas stream comprise at least one particulate control device and at least one other piece of emission control technology, and wherein Step (C) is achieved by supplying the one or more gypsum sorbent compounds to at least two injection points that are individually upstream of the air heater and individually upstream of the at least one particulate control device.
16. The method of claim 14 , wherein the combustion flue gas stream is in communication with at least one air heater and two or more pieces of emission control technology in communication with the flue gas stream comprise at least one particulate control device and at least one other piece of emission control technology, and wherein Step (C) is achieved by supplying the one or more gypsum sorbent compounds to at least two injection points that are individually upstream of the air heater and individually inside the at least one particulate control device.
17. The method of claim 14 , wherein the combustion flue gas stream is in communication with at least one air heater and two or more pieces of emission control technology in communication with the flue gas stream comprise at least one particulate control device and at least one other piece of emission control technology, and wherein Step (C) is achieved by supplying the one or more gypsum sorbent compounds to at least two injection points that are individually upstream of the air heater and individually downstream of the at least one particulate control device.
18. The method of claim 14 , wherein Step (B) is conducted at a temperature below about 900° F.
19. The method of claim 14 , wherein Step (B) is conducted at a temperature in the range of about 750° F. to about 900° F.
20. The method of claim 14 , wherein Step (B) is conducted at a temperature below about 400° F.
21. A method for reducing the amount and/or concentration of one or more selenium compounds, one or more arsenic compounds, one or more lead compounds and/or one or more other RCRA metals, or RCRA metal compounds, in a combustion flue gas stream and/or in one or more pieces of emission control technology in communication with the flue gas stream, regardless of whether any one or more of the selenium compounds, the arsenic compounds, the lead compounds or any of the other RCRA metals or RCRA metal compounds are in the gas phase or some other phase, the method comprising the steps of:
(a) supplying one or more gypsum sorbent compounds to one or more injection points in the combustion flue gas stream and/or one or more pieces of emission control technology combustion flue gas stream and/or in one or more pieces of emission control technology in communication with the flue gas stream;
(b) injecting the one or more gypsum sorbent compounds into the combustion flue gas stream and/or one or more pieces of emission control technology combustion flue gas stream and/or in one or more pieces of emission control technology in communication with the flue gas stream via the one or more injection points; and
(c) reducing the amount and/or concentration in the combustion flue gas stream of the one or more selenium compounds, the one or more arsenic compounds, the one or more lead compounds and/or the one or more other RCRA metals, or RCRA metal compounds, regardless of whether such selenium compounds, such arsenic compounds, such lead compounds and/or such other RCRA metals or RCRA metal compounds are in the gas phase or some other phase by capturing, sequestering, binding and/or reacting the one or more selenium compounds, the one or more arsenic compounds, the one or more lead compounds and/or the one or more other RCRA metals, or RCRA metal compounds, on or with the one or more gypsum sorbent compounds,
wherein the one or more pieces of emission control technology in communication with the flue gas stream comprise at least one particulate control device or at least one air heater and wherein Step (c) is achieved by supplying and injecting the one or more gypsum sorbent compounds in Step (b) to at least one injection point upstream of either the at least one particulate control device or the least one air heater.
22. The method of claim 21 , wherein the combustion flue gas stream is in communication with at least one air heater and two or more pieces of emission control technology in communication with the flue gas stream comprise at least one particulate control device and at least one other piece of emission control technology, and wherein Step (c) is achieved by supplying the one or more gypsum sorbent compounds to at least two injection points that are individually upstream of the air heater and individually upstream of the at least one particulate control device.
23. The method of claim 21 , wherein the combustion flue gas stream is in communication with at least one air heater and two or more pieces of emission control technology in communication with the flue gas stream comprise at least one particulate control device and at least one other piece of emission control technology, and wherein Step (c) is achieved by supplying the one or more gypsum sorbent compounds to at least two injection points that are individually upstream of the air heater and individually inside the at least one particulate control device.
24. The method of claim 21 , wherein the combustion flue gas stream is in communication with at least one air heater and two or more pieces of emission control technology in communication with the flue gas stream comprise at least one particulate control device and at least one other piece of emission control technology, and wherein Step (c) is achieved by supplying the one or more gypsum-based sorbent compounds to at least two injection points that are individually upstream of the air heater and individually downstream of the at least one particulate control device.