# US 10,478,775 B2 · Metal capture in a flue gas using sorbent injection > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,478,775 B2 - Document ID: US10478775B2 - Status: Granted - Kind: B2 - Application number: 15/653,696 - Filed: 2017-07-19 - Published: 2018-02-01 - Granted: 2019-11-19 - Earliest claimed: 2016-08-01 - Assignees: The Babcock & Wilcox Company - Applicants: The Babcock & Wilcox Company - Inventors: Prasanna Seshadri; Richard DeVault - Web page: https://patentgrep.com/patent/US10478775B2 ## CPC - B01D 53/64: Heavy metals or compounds thereof, e.g. mercury - B01D 53/1437: {Pretreatment by adsorption} - B01D 53/46: Removing components of defined structure - B01D 53/501: {by treating the gases with a solution or a suspension of an alkali or earth-alkali or ammonium compound} - B01D 53/80: Semi-solid phase processes, i.e. by using slurries - B01D 53/83: with moving reactants - B01D 2251/404: of calcium - B01D 2251/608: Sulfates - B01D 2252/2056: Sulfur compounds, e.g. Sulfolane, thiols - B01D 2253/1124: Metal oxides - B01D 2257/302: Sulfur oxides - B01D 2257/55: Compounds of silicon, phosphorus, germanium or arsenic - B01D 2257/60: Heavy metals or heavy metal compounds - B01D 2257/93: Toxic compounds not provided for in groups B01D2257/00 - B01D2257/708 - B01D 2258/0283: Flue gases - B01D: SEPARATION (separating solids from solids by wet methods B03B, B03D; by pneumatic jigs or tables B03B; by other dry methods B07; magnetic or electrostatic separation of solid materials from solid materials or fluids, separation by high-voltage electric fields B03C; centrifuges, vortex apparatus B04; presses per se for squeezing-out liquid from liquid-containing material B30B9/02; treatment of water C02F, e.g. softening by ion-exchange C02F1/42; {arrangements of air intake cleaners in gas turbine plants F02C7/05} ; arrangements or mounting of filters in air-conditioning, air-humidification or ventilation F24F13/28) ## Abstract 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. ## Claims ### Claim 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. ### Claim 2 (depends on 1) 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. ### Claim 3 (depends on 1) 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. ### Claim 4 (depends on 1) 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. ### Claim 5 (depends on 1) The method of claim 1, wherein Step (II) is conducted at a temperature below about 900° F. ### Claim 6 (depends on 1) The method of claim 1, wherein Step (II) is conducted at a temperature in the range of about 750° F. to about 900° F. ### Claim 7 (depends on 1) The method of claim 1, wherein Step (II) is conducted at a temperature below about 400° F. ### Claim 8 (depends on 1) The method of claim 1, wherein at least the gas phase selenium concentration is reduced. ### Claim 9 (depends on 1) The method of claim 1, wherein at least the gas phase selenium and gas phase lead concentrations are reduced. ### Claim 10 (depends on 1) The method of claim 1, wherein at least the gas phase selenium and gas phase arsenic concentrations are reduced. ### Claim 11 (depends on 1) The method of claim 1, wherein at least the gas phase arsenic concentration is reduced. ### Claim 12 (depends on 1) The method of claim 1, wherein at least the gas phase arsenic and gas phase lead concentrations are reduced. ### Claim 13 (depends on 1) The method of claim 1, wherein the gas phase selenium, gas phase arsenic and the gas phase lead concentrations are reduced. ### Claim 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. ### Claim 15 (depends on 14) 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. ### Claim 16 (depends on 14) 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. ### Claim 17 (depends on 14) 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. ### Claim 18 (depends on 14) The method of claim 14, wherein Step (B) is conducted at a temperature below about 900° F. ### Claim 19 (depends on 14) The method of claim 14, wherein Step (B) is conducted at a temperature in the range of about 750° F. to about 900° F. ### Claim 20 (depends on 14) The method of claim 14, wherein Step (B) is conducted at a temperature below about 400° F. ### Claim 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. ### Claim 22 (depends on 21) 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. ### Claim 23 (depends on 21) 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. ### Claim 24 (depends on 21) 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.