# US 2013/0156664 A1 · Dry sorbent injection during steady-state conditions in dry scrubber > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2013/0156664 A1 - Document ID: US20130156664A1 - Status: Published application - Kind: A1 - Application number: 13/548,147 - Filed: 2012-07-12 - Published: 2013-06-20 - Earliest claimed: 2011-09-29 - Assignees: Babcock & Wilcox Power Generation Group, Inc. - Inventors: BRYAN J. JANKURA; Anthony A. Silva; Edward J. Campobenedetto - Web page: https://patentgrep.com/patent/US20130156664A1 ## CPC - B01D 53/504: {characterised by a specific device} - B01D 53/502: {characterised by a specific solution or suspension} - B01D 53/505: {in a spray drying process} - B01D 53/508: {by treating the gases with solids} - B01D 53/80: Semi-solid phase processes, i.e. by using slurries - B01D 53/83: with moving reactants - F23J 15/003: {for supplying chemicals to fumes, e.g. using injection devices} - F23J 15/025: {using filters} - B01D 2251/404: of calcium - B01D 2251/604: Hydroxides - B01D 2258/0283: Flue gases - F23J 2215/20: Sulfur; Compounds thereof - F23J 2217/101: Baghouse type - F23J 2219/60: Sorption with dry devices, e.g. beds - 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) - F23J: REMOVAL OR TREATMENT OF COMBUSTION PRODUCTS OR COMBUSTION RESIDUES; FLUES (combustion apparatus for consuming smoke or fumes, e.g. exhaust gases, F23G7/06) ## Abstract Methods of reducing emissions levels during steady-state conditions are disclosed for use with a dry scrubber desulfurization system. A dry calcium hydroxide powder is injected into the gas flowpath and watered in the spray dryer absorber. The resulting slurry is then deposited on the filter bags in the baghouse. This can be done at lower temperatures than the spray dryer absorber would otherwise be operable, enabling desulfurization to occur earlier in the combustion process, particularly during startup of a cold boiler at ambient temperature. The operation of the boiler can also be backed up, made up, trimmed, or augmented depending on various operating scenarios. ## Claims ### Claim 1 A method for reducing combustion emissions produced during normal operating conditions in a combustion system system having a gas flowpath that travels from a combustion chamber through a spray dryer absorber to a baghouse downstream of the spray dryer absorber, the method comprising: mixing a dry calcium hydroxide powder into a flue gas at an injection location downstream of the combustion chamber and upstream of the baghouse; spraying water into the flue gas in the spray dryer absorber to humidify and reduce the temperature of the flue gas; and passing the flue gas through the baghouse, wherein the calcium hydroxide powder captures pollutants in the flue gas. ### Claim 2 (depends on 1) The method of claim 1, wherein no liquid is added to the carrier gas between the injection location and the spray dryer absorber. ### Claim 3 (depends on 1) The method of claim 1, wherein the water sprayed into the flue gas comes from a recycle system for recycling solids from the baghouse. ### Claim 4 (depends on 1) The method of claim 1, wherein the gas flowpath travels through an air preheater located between the combustion chamber and the spray dryer absorber. ### Claim 5 (depends on 4) The method of claim 4, wherein the injection location is located between the air preheater and the spray dryer absorber. ### Claim 6 (depends on 4) The method of claim 4, wherein the injection location is upstream of the air preheater. ### Claim 7 (depends on 4) The method of claim 4, further comprising a particulate collection device between the air preheater and the spray dryer absorber. ### Claim 8 (depends on 7) The method of claim 7, wherein the injection location is downstream of the particulate collection device. ### Claim 9 (depends on 1) The method of claim 1, wherein the injection location is between the spray dryer absorber and the baghouse. ### Claim 10 (depends on 1) The method of claim 1, wherein the baghouse is a pulse jet fabric filter, a shake deflate fabric filter, or a reverse gas fabric filter. ### Claim 11 (depends on 1) The method of claim 1, wherein the water sprayed into the flue gas in the spray dryer absorber is in the form of an alkaline slurry. ### Claim 12 (depends on 1) The method of claim 1, wherein the amount of dry calcium hydroxide powder mixed into the flue gas varies over time depending on an emissions level in the flue gas. ### Claim 13 (depends on 1) The method of claim 1, wherein the water sprayed into the flue gas in the spray dryer absorber is in the form of water, and an alkaline slurry is not being sprayed in the spray dryer absorber. ### Claim 14 (depends on 1) The method of claim 1, wherein the flue gas entering the spray dryer absorber has a temperature of about 220° F. or higher. ### Claim 15 (depends on 1) The method of claim 1, wherein flue gas exiting the combustion chamber has a temperature of 400° F. or higher. ### Claim 16 (depends on 1) The method of claim 1, wherein the combustion system is selected from boilers, kilns, furnaces, smelters, roasters, batteries, heaters, ovens, or incinerators. ### Claim 17 A method for operating a combustion system that uses a spray dryer absorber to clean a flue gas, the method comprising: mixing a dry calcium hydroxide powder into the flue gas at an injection location downstream of a combustion chamber and upstream of the spray dryer absorber; spraying water into the flue gas in the spray dryer absorber to form a cleaned particulate-containing flue gas; and depositing the particulates in the particulate-containing flue gas in the baghouse to form a filter cake that reduces combustion emissions. ### Claim 18 (depends on 17) The method of claim 17, wherein the amount of dry calcium hydroxide powder injected into the flue gas is determined by comparing an emissions level to a predetermined value. ### Claim 19 (depends on 17) The method of claim 17, wherein no liquid is added to the flue gas between the injection location and the spray dryer absorber. ### Claim 20 (depends on 17) The method of claim 17, wherein the injection location is located upstream of an air preheater that is also located upstream of the spray dryer absorber. ### Claim 21 (depends on 17) The method of claim 17, wherein the injection location is located between the spray dryer absorber and an air preheater that is located upstream of the spray dryer absorber. ### Claim 22 (depends on 17) The method of claim 17, wherein the water sprayed in the spray dryer absorber is in the form of an alkaline slurry. ### Claim 23 (depends on 17) The method of claim 17, wherein the water sprayed in the spray dryer absorber comes from a recycle system for recycling solids from the baghouse. ### Claim 24 (depends on 17) The method of claim 17, wherein the water sprayed in the spray dryer absorber is sprayed through auxiliary nozzles, and an atomizer of the spray dryer absorber is not operating. ### Claim 25 (depends on 17) The method of claim 17, wherein the flue gas entering the spray dryer absorber has a temperature of about 220° F. or higher. ### Claim 26 (depends on 17) The method of claim 17, wherein flue gas exiting the combustion chamber has a temperature of 400° F. or higher. ### Claim 27 (depends on 17) The method of claim 17, wherein the combustion system is selected from boilers, kilns, furnaces, smelters, roasters, batteries, heaters, ovens, or incinerators.