System and process for removal of pollutants from a gas stream

• US 6,610,263 B2
• Filed: 07/31/2001
• Issued: 08/26/2003
• Est. Priority Date: 08/01/2000
• Status: Expired due to Fees

• Current Assignee: Enviroscrub Technologies Corp.
• Original Assignee: Enviroscrub Technologies Corp.
• Inventors: Carlton, Steve C., Hammel, Charles F., Boren, Richard M., Larson, Joshua E., Axen, Steve G., Kronbeck, Kevin P., Tuzinski, Patrick A., Huff, Ray V., Pahlman, John E.
• Primary Examiner(s): Silverman, Stanley S.
• Assistant Examiner(s): Vanoy, Timothy C.
• Application Number:
  US09/919,600
• Publication Number:
  US 20020168302A1
• Time in Patent Office: 756 Days
• Field of Search: 95/22, 95/23, 961/13, 961/14, 423/210, 423/215.5, 423/244.06, 423/239.1, 423/DIG.5, 423/230, 423/393, 423/522, 423/541.1, 423/548, 423/544, 423/395, 423/400
• US Class Current: 423/239.1
• CPC Class Codes: B01D 2253/10 Inorganic adsorbents
• CPC Class Codes: B01D 2253/112 Metals or metal compounds not provided for in B01D2253/104 or B01D2253/106
• CPC Class Codes: B01D 2253/304 Linear dimensions, e.g. particle shape, diameter
• CPC Class Codes: B01D 2253/306 Surface area, e.g. BET-specific surface
• CPC Class Codes: B01D 2257/302 Sulfur oxides
• CPC Class Codes: B01D 2257/304 Hydrogen sulfide
• CPC Class Codes: B01D 2257/404 Nitrogen oxides other than dinitrogen oxide
• CPC Class Codes: B01D 2257/602 Mercury or mercury compounds
• CPC Class Codes: B01D 2258/00 Sources of waste gases
• CPC Class Codes: B01D 2259/40 Further details for adsorption processes and devices
• CPC Class Codes: B01D 2259/41 using plural beds of the same adsorbent in series
• CPC Class Codes: B01D 53/04 with stationary adsorbents B01D53/025 takes precedence
• CPC Class Codes: B01D 53/0423 Beds in columns
• CPC Class Codes: B01D 53/0446 Means for feeding or distributing gases
• CPC Class Codes: B01D 53/0454 Controlling adsorption controlling temperature swing adsorption B01D53/0462, controlling pressure swing adsorption B01D53/047
• CPC Class Codes: B01D 53/06 with moving adsorbents, e.g. rotating beds B01D53/025 takes precedence
• CPC Class Codes: B01D 53/08 according to the "moving bed" method
• CPC Class Codes: B01D 53/12 according to the "fluidised technique"
• CPC Class Codes: B01D 53/30 Controlling by gas-analysis apparatus regulating non electrical variables in general G05D
• CPC Class Codes: B01D 53/346 Controlling the process
• CPC Class Codes: B01D 53/508 : by treating the gases with solids
• CPC Class Codes: B01D 53/565 : by treating the gases with solids
• CPC Class Codes: B01D 53/60 : Simultaneously removing sulfur oxides and nitrogen oxides
• CPC Class Codes: B01D 53/64 : Heavy metals or compounds thereof, e.g. mercury
• CPC Class Codes: B01D 53/83 : with moving reactants
• CPC Class Codes: B01D 53/8609 : Sulfur oxides
• CPC Class Codes: B01D 53/8628 : Processes characterised by a specific catalyst
• CPC Class Codes: B01D 53/8665 : Removing heavy metals or compounds thereof, e.g. mercury
• CPC Class Codes: B01J 23/34 : Manganese
• CPC Class Codes: B01J 23/92 : of catalysts comprising metals, oxides or hydroxides provided for in groups B01J23/02 - B01J23/36
• CPC Class Codes: B01J 35/40 : characterised by dimensions, e.g. grain size in a colloidal state B01J35/23; crystallite size B01J35/77
• CPC Class Codes: C22B 43/00 : Obtaining mercury
• CPC Class Codes: C22B 7/006 : Wet processes
• CPC Class Codes: C22B 7/02 : Working-up flue dust
• CPC Class Codes: F23J 15/006 : Layout of treatment plant
• CPC Class Codes: F23J 15/02 : of purifiers, e.g. for removing noxious material traps for solid residues F23J3/04
• CPC Class Codes: F23J 2215/10 : Nitrogen; Compounds thereof
• CPC Class Codes: F23J 2215/20 : Sulfur; Compounds thereof
• CPC Class Codes: F23J 2215/60 : Heavy metals; Compounds thereof
• CPC Class Codes: F23J 2217/101 : Baghouse type
• CPC Class Codes: F23J 2219/60 : Sorption with dry devices, e.g. beds
• CPC Class Codes: G05D 16/028 : Controlling a pressure difference control of flow G05D7/00
• CPC Class Codes: G05D 16/2013 : using throttling means as controlling means
• CPC Class Codes: G05D 21/02 : characterised by the use of electric means
• CPC Class Codes: G05D 23/1917 : using digital means
• CPC Class Codes: G05D 7/0635 : by action on throttling means G05D7/0688, G05D7/0694 take precedence
• CPC Class Codes: Y02C 20/10 : of nitrous oxide (N2O)
• CPC Class Codes: Y02P 10/122 : by capturing or storing CO2
• CPC Class Codes: Y02P 10/146 : Perfluorocarbons [PFC]; Hydrofluorocarbons [HFC]; Sulfur hexafluoride [SF6]
• CPC Class Codes: Y02P 10/20 : Recycling
• CPC Class Codes: Y10S 423/05 : Automatic, including computer, control

Abstract

System for removal of targeted pollutants, such as oxides of sulfur, oxides of nitrogen, mercury compounds and ash, from combustion and other industrial process gases and processes utilizing the system. Oxides of manganese are utilized as the primary sorbent in the system for removal or capture of pollutants. The oxides of manganese are introduced from feeders into reaction zones of the system where they are contacted with a gas from which pollutants are to be removed. With respect to pollutant removal, the sorbent may interact with a pollutant as a catalyst, reactant, adsorbent or absorbent. Removal may occur in single-stage, dual-stage, or multi-stage systems with a variety of different configurations and reaction zones, e.g., bag house, cyclones, fluidized beds, and the like. Process parameters, particularly system differential pressure, are controlled by electronic controls to maintain minimal system differential pressure, and to monitor and adjust pollutant removal efficiencies. Reacted sorbent may be removed from the reaction action zones for recycling or recycled or regenerated with useful and marketable by-products being recovered during regeneration.

Claims

1. A process for dry removal of SO_X and NO_X from a gas stream in a single reaction zone, comprising the steps of:

a. providing a continuous process system having a single reaction zone for dry removal of SO_X at a removal rate of at least 99% and of NO_X at a removal rate of at least 96% from a gas stream in the reaction zone, the process comprising the steps of;

i. configuring a dry sorbent-reactant feeder for controlled feed of a supply of dry sorbent-reactant of regenerable oxides of manganese and/or regenerated oxides of manganese, wherein the feeder is configured to handle and feed the dry sorbent-reactant in particle form;

ii. connecting the reaction zone to the sorbent-reactant feeder and to a source of a gas containing SO_X and NO_X, the reaction zone having a first portion and a second portion, the first portion being configured for introduction of the dry sorbent-reactant and the gas and the second portion being configured to receive the gas and the dry sorbent-reactant from the first portion;

the reaction zone being configured to substantially strip the gas of SO_X at a targeted SO_X capture rate set point of at least 99% through formation of sulfates of manganese, to substantially strip the gas of NO_X at a targeted NO_X capture rate set point of at least 96% through formation of nitrates of manganese, and to render the gas free of the sorbent-reactant prior to the gas being vented from the reaction zone;

b. selecting and introducing the dry sorbent-reactant into the feeder, the dry sorbent reactant being oxides of manganese selected so that upon regeneration the sorbent-reactant is in particle form and has the chemical formula MnO_X, where X is about 1.8 to 2.0, the oxides of manganese having a particle size ranging from about 6 microns to about 500 microns and a BET value ranging from about 135 to about 1000 m²/g;

c. operating the system so that the dry sorbent-reactant and gas are introduced into the first portion of the reaction zone, the gas being at temperatures ranging from ambient temperature to about 350°

F., and so that the gas and the dry sorbent-reactant are in contact for a time sufficient to effect SO_X capture at a targeted SO_X capture rate set point of at least 99% and to effect NO_X capture at a targeted NO_X capture rate set point of at least 96%;

d. routing the gas and the dry sorbent-reactant into the first portion of the reaction zone and then into the second portion of the reaction zone so that the gas and the dry sorbent-reactant are in contact for a time sufficient to effect SO_X capture at the targeted SO_X capture rate set point of at least 99% and to effect NO_X at the targeted NO_X capture rate set point of at least 96%, the SO_X being captured through formation of sulfates of manganese and the NO_X being captured through the formation of nitrates of manganese;

e. rendering the gas in the reaction zone free of the dry sorbent-reactant; and

f. venting the gas from the reaction zone.

3. The process of claim 1 or claim 2, wherein the targeted NO_X capture rate set point is at least 97.0% and NO_X is removed a capture rate of at least 97.0%.

4. The process of claim 1 or claim 2, wherein the targeted NO_X capture rate set point is at least 98.0% and NO_X is removed at a capture rate of at least 98.0%.

5. The process of claim 1 or claim 2, wherein the targeted NO_X capture rate set point is at least 99.0% and NO_X is removed at a capture rate of at least 99.0%.

14. The process of any one of claims 1, 2, 6 or 10, wherein the process further comprises the steps of:

removing the sorbent-reactant from the reaction zone of the system;

washing the sorbent-reactant in a dilute acid rinse to dissolve sulfates and/or nitrates of manganese on the surface of sorbent-reactant particles into solution and thereby cleaning the sorbent-reactant;

separating the cleaned sorbent-reactant from the acid rinse;

conveying the cleaned sorbent-reactant to a dryer;

drying the cleaned sorbent-reactant;

conveying the cleaned sorbent-reactant to a pulverizer;

de-agglomerating and sizing the cleaned sorbent-reactant; and

conveying the de-agglomerated and sized clean sorbent-reactant to the sorbent-reactant feeder for reintroduction into the system.

15. The process one of any one of claims 1, 2, 6 or 10, wherein the process further comprises the steps of:

removing the sorbent-reactant from the reaction zone of the system;

washing the sorbent-reactant in a dilute acid rinse to dissolve sulfates and/or nitrates of manganese on the surface of sorbent-reactant particles into solution and thereby cleaning the sorbent-reactant;

separating the cleaned sorbent-reactant from the acid rinse to provide a filtrate containing dissolved sulfates and/or nitrates of manganese;

adding alkali or ammonium hydroxide to the filtrate to form a sorbent-reactant precipitate of oxides and hydroxides of manganese and a liquor containing alkali or ammonium sulfates and/or nitrates;

separating the sorbent-reactant precipitate from the liquor, the liquor being routed for further processing into marketable products or for distribution and/or sale as a useful by-product;

rinsing the sorbent-reactant precipitate;

drying the sorbent-reactant precipitate to form sorbent-reactant in an oxidizing atmosphere; and

de-agglomerating and sizing the sorbent-reactant; and

conveying the dc-agglomerated and sized sorbent-reactant to the feeder.

16. The process of any one of claims 1, 2, 6, or 10, wherein the process further comprises the steps of:

removing sorbent-reactant from the reaction zone of the system;

heating the sorbent-reactant to a temperature ranging from about 350°

F. to about 1742°

F. to thermally decompose the nitrates of manganese, to desorb NO₂, and to regenerate sorbent-reactant;

passing the desorbed NO₂ through a wet scrubber containing water and an oxidant to form a nitric acid liquor;

routing the nitric acid liquor for further distribution and/or sale as a useful product or on for further processing.

17. The process of any one of claims 1, 2, 6 or 10, wherein the process further comprises the steps of:

removing sorbent-reactant from the reaction zone of the system where primarily NO_X capture occurred by reacting with the sorbent to form nitrates of manganese;

heating the sorbent-reactant to a temperature ranging from about 350°

F. to about 1742°

F. to thermally decompose the nitrates of manganese, to desorb NO₂, and to regenerate sorbent-reactant;

passing the desorbed NO₂ through a wet scrubber containing water and an oxidant to form a nitric acid liquor;

adding an ammonium or alkali hydroxide to the acid liquor to form a liquor containing ammonium or alkali nitrates; and

routing the liquor for distribution and/or sale as a useful by-product or for further processing into marketable products.

18. The process of any one of claims 1, 2, 6 or 10, wherein the process further comprises the steps of:

removing sorbent-reactant from the reaction zone of the system;

heating the sorbent-reactant to a temperature ranging from about 350°

F. to about 1742°

F. to desorb NO₂, the desorbed NO₂ being routed for further processing and/or handling;

heating the sorbent-reactant to a temperature above 1742°

F. to desorb SO_X and to regenerate the sorbent-reactant, the desorbed SO_X being routed for further processing and/or handling; and

routing the regenerated sorbent-reactant to the feeder.

2. A process for dry removal of SO_X and NO_X from a gas stream in a single reaction zone, comprising the steps of:

a. providing a continuous process system having a single reaction zone for dry removal of SO_X at a removal rate of at least 99% and of NO_X at a removal rate of at least 96% from a gas stream in the reaction zone, the process comprising the steps of;

i. configuring a dry sorbent-reactant feeder for controlled feed of a supply of dry sorbent-reactant of regenerable oxides of manganese and/or regenerated oxides of manganese, wherein the feeder is configured to handle and feed the dry sorbent-reactant in particle form;

ii. connecting the reaction zone to the sorbent-reactant feeder and to a source of a gas containing SO_X and NO_X, the reaction zone having a first portion and a second portion, the first portion being configured for introduction of the dry sorbent-reactant and the gas and the second portion being configured to receive the gas and the dry sorbent-reactant from the first portion;

the reaction zone being configured to substantially strip the gas of SO_X at a targeted SO_X capture rate set point of at least 99% through formation of sulfates of manganese, to substantially strip the gas of NO_X at a targeted NO_X capture rate set point of at least 96% through formation of nitrates of manganese, and to render the gas free of the sorbent-reactant prior to the gas being vented from the reaction zone;

b. selecting and introducing the dry sorbent-reactant into the feeder, the dry sorbent-reactant being oxides of manganese selected so that upon regeneration the sorbent-reactant is in particle form and has the chemical formula MnO_X, where X is about 1.5 to 2.0, the oxides of manganese having a particle size ranging from about 6 microns to about 500 microns and a BET value ranging from about 1 to about 1000 m²/g;

c. operating the system so that the dry sorbent-reactant and gas are introduced into the first portion of the reaction zone, the gas being at temperatures ranging from ambient temperature to about 350°

F., and so that the gas and the dry sorbent-reactant are in contact for a time sufficient to effect SO_X capture at a targeted SO_X capture rate set point of at least 99% and to effect NO_X capture at a targeted NO_X capture rate set point of at least 96%;

d. routing the gas and the dry sorbent-reactant into the first portion of the reaction zone and then into the second portion of the reaction zone so that the gas and the dry sorbent-reactant are in contact for a time sufficient to effect SO_X capture at the targeted SO_X capture rate set point of at least 99% and to effect NO_X at the targeted NO_X capture rate set point of at least 96%, the SO_X being captured through formation of sulfates of manganese and the NO_X being captured through the formation of nitrates of manganese;

e. rendering the gas in the reaction zone free of the dry sorbent-reactant; and

f. venting the gas from the reaction zone.

6. A process for dry removal of SO_X and NO_X from a gas stream in a single reaction zone, comprising the steps of:

a. providing a continuous process system having a single reaction zone for dry removal of SO_X at a removal rate of at least 98% and of NO_X at a removal rate of at least 90% from a gas stream in the reaction zone, the process comprising the steps of;

i. configuring a dry sorbent-reactant feeder for controlled feed of a supply of dry sorbent-reactant of regenerable oxides of manganese and/or regenerated oxides of manganese, wherein the feeder is configured to handle and feed the dry sorbent-reactant in particle form;

ii. connecting the reaction zone to the sorbent-reactant feeder and to a source of a gas containing SO_X and NO_X, the reaction zone having a first portion and a second portion, the first portion being configured for introduction of the dry sorbent-reactant and the gas and the second portion being configured to receive the gas and the dry sorbent-reactant from the first portion;

the reaction zone being configured to substantially strip the gas of SO_X at a targeted SO_X capture rate set point of at least 99% through formation of sulfates of manganese, to substantially strip the gas of NO_X at a targeted NO_X capture rate set point of at least 96% through formation of nitrates of manganese, and to render the gas free of the sorbent-reactant prior to the gas being vented from the reaction zone;

b. selecting and introducing the dry sorbent-reactant into the feeder, the dry sorbent-reactant being oxides of manganese selected so that upon regeneration the sorbent-reactant is in particle form and has the chemical formula MnO_X, where X is about 1.5 to 2.0, the oxides of manganese having a particle size ranging from about 6 microns to about 500 microns and a BET value ranging from about 1 to about 1000 m²/g;

c. operating the system so that the dry sorbent-reactant and gas are introduced into the first portion of the reaction zone, the gas being at temperatures ranging from ambient temperature to about 350°

F., and so that the gas and the dry sorbent-reactant are in contact for a time sufficient to effect SO_X capture at a targeted SO_X capture rate set point of at least 98% and to effect NO_X capture at a targeted NO_X capture rate set point of at least 90%;

d. routing the gas and the dry sorbent-reactant into the first portion of the reaction zone and then into the second portion of the reaction zone so that the gas and the dry sorbent-reactant are in contact for a time sufficient to effect SO_X capture at the targeted SO_X capture rate set point of at least 98% and to effect NO_X at the targeted NO_X capture rate set point of at least 90%, the SO_X being captured through formation of sulfates of manganese and the NO_X being captured through the formation of nitrates of manganese;

e. rendering the gas in the reaction zone free of the dry sorbent-reactant; and

f. venting the gas from the reaction zone.

7. The process of claim 6, wherein the targeted SO_X capture rate set point is at least 99.0%, SO_X is removed at a capture rate of at least 99.0%, the targeted NO_X capture rate set point is at least 92.0% and NO_X is removed at a capture rate of at least 92.0%.

8. The process of claim 6, wherein the targeted SO_X capture rate set point is at least 99.0%, SO_X is removed at a capture rate of at least 99.0%, the targeted NO_X capture rate set point is at least 94.0% and NO_X is removed at a capture rate of at least 94.0%.

9. The process of claim 6, wherein the targeted SO_X capture rate set point is at least 99.0%, SO_X is removed at a capture rate of at least 99.0%, the targeted NO_X capture rate set point is at least 95.0% and NO_X is removed at a capture rate of at least 95.0%.

10. A process for dry removal of SO_X and NO_X from a gas stream in a single reaction zone, comprising the steps of:

a. providing a continuous process system having a single reaction zone for dry removal of SO_X at a removal rate of at least 60% and of NO_X at a removal rate of at least 60% from a gas stream in the reaction zone, the process comprising the steps of;

i. configuring a dry sorbent-reactant feeder for controlled feed of a supply of dry sorbent-reactant of regenerable oxides of manganese and/or regenerated oxides of manganese, wherein the feeder is configured to handle and feed the dry sorbent-reactant in particle form;

ii. connecting the reaction zone to the sorbent-reactant feeder and to a source of a gas containing SO_X and NO_X, the reaction zone having a first portion and a second portion, the first portion being configured for introduction of the dry sorbent-reactant and the gas and the second portion being configured to receive the gas and the dry sorbent-reactant from the first portion;

the reaction zone being configured to substantially strip the gas of SO_X at a targeted SO_X capture rate set point of at least 60% through formation of sulfates of manganese, to substantially strip the gas of NO_X at a targeted NO_X capture rate set point of at least 60% through formation of nitrates of manganese, and to render the gas free of the sorbent-reactant prior to the gas being vented from the reaction zone;

b. selecting and introducing the dry sorbent-reactant into the feeder, the dry sorbent-reactant being oxides of manganese selected so that upon regeneration the sorbent-reactant is in particle form and has the chemical formula MnO_X, where X is about 1.5 to 2.0, the oxides of manganese having a particle size ranging from about 6 microns to about 500 microns and a BET value ranging from about 1 to about 1000 m²/g;

c. operating the system so that the dry sorbent-reactant and gas are introduced into the first portion of the reaction zone, the gas being at temperatures ranging from ambient temperature to about 350°

F., and so that the gas and the dry sorbent-reactant are in contact for a time sufficient to effect SO_X capture at a targeted SO_X capture rate set point of at least 60% and to effect NO_X capture at a targeted NO_X capture rate set point of at least 60%;

d. routing the gas and the dry sorbent-reactant into the first portion of the reaction zone and then into the second portion of the reaction zone so that the gas and the dry sorbent-reactant are in contact for a time sufficient to effect SO_X capture at the targeted SO_X capture rate set point of at least 60% and to effect NO_X at the targeted NO_X capture rate set point of at least 60%, the SO_X being captured through formation of sulfates of manganese and the NO_X being captured through the formation of nitrates of manganese;

e. rendering the gas in the reaction zone free of the dry sorbent-reactant; and

f. venting the gas from the reaction zone.

11. The process of claim 10, wherein the targeted SO_X capture rate set point is at least 70.0%, SO_X is removed at a capture rate of at least 70.0%, the targeted NO_X capture rate set point is at least 70.0% and NO_X is removed at a capture rate of at least 70.0%.

12. The process of claim 10, wherein the targeted SO_X capture rate set point is at least 80.0%, SO_X is removed at a capture rate of at least 80.0%, the targeted NO_X capture rate set point is at least 80.0% and NO_X is removed at a capture rate of at least 80.0%.

13. The process of claim 10, wherein the targeted SO_X, capture rate set point is at least 90.0%, SO_X is removed at a capture rate of at least 90.0%, the targeted NO_X capture rate set point is at least 90.0% and NO_X is removed at a capture rate of at least 90.0%.