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WO2006017801A2 - Reduction d'oxyde d'azote dans les gaz de carneau de combustion - Google Patents

Reduction d'oxyde d'azote dans les gaz de carneau de combustion Download PDF

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Publication number
WO2006017801A2
WO2006017801A2 PCT/US2005/028030 US2005028030W WO2006017801A2 WO 2006017801 A2 WO2006017801 A2 WO 2006017801A2 US 2005028030 W US2005028030 W US 2005028030W WO 2006017801 A2 WO2006017801 A2 WO 2006017801A2
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WO
WIPO (PCT)
Prior art keywords
carbonaceous material
emissions
carbonaceous
reducing
burn
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/US2005/028030
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English (en)
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WO2006017801A3 (fr
Inventor
Anthony J. Kriech
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Individual
Original Assignee
Individual
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Filing date
Publication date
Application filed by Individual filed Critical Individual
Publication of WO2006017801A2 publication Critical patent/WO2006017801A2/fr
Publication of WO2006017801A3 publication Critical patent/WO2006017801A3/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23K—FEEDING FUEL TO COMBUSTION APPARATUS
    • F23K1/00—Preparation of lump or pulverulent fuel in readiness for delivery to combustion apparatus
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23K—FEEDING FUEL TO COMBUSTION APPARATUS
    • F23K1/00—Preparation of lump or pulverulent fuel in readiness for delivery to combustion apparatus
    • F23K1/02—Mixing solid fuel with a liquid, e.g. preparing slurries
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23K—FEEDING FUEL TO COMBUSTION APPARATUS
    • F23K2201/00—Pretreatment of solid fuel
    • F23K2201/50—Blending
    • F23K2201/505—Blending with additives

Definitions

  • the present invention is based on United States Provisional Patent Application Serial No. 60/599,111, filed August 5, 2004, and claims priority to United States Provisional Patent Application Serial No. 60/599,111 under 35 U.S.C. ⁇ 120.
  • the present invention relates to a method of reducing nitrogen oxide emissions in combustion systems. More specifically, the present invention is directed to a method of decreasing the concentration of nitrogen oxides in flue gases emitted into the atmosphere from combustion systems that burn carbonaceous materials.
  • Nitrogen oxides are major air pollutants emitted by boilers, furnaces, and other combustion sources that burn carbonaceous materials. Nitrogen oxides include nitric oxide (NO), nitrogen dioxide (NO 2 ), and nitrous oxide (N 2 O). Total N0+N0 2 concentration is usually referred to as NO x . Combustion sources produce nitrogen oxides mainly in the form of NO. Some NO 2 and N 2 O are also formed, but their concentrations are typically less than 5% of the NO concentration, which is generally in the range of about 200-1000 ppm. Nitrogen oxides are the subject of growing concern because they are toxic compounds, and are precursors to acid rain and photochemical smog. Nitrous oxide also contributes to the greenhouse effect.
  • Combustion modifications such as low NO x burners (LNB) and overfire air (OFA) injection provide only modest NO x control, reducing NO x concentrations by about 30-50%.
  • LNB low NO x burners
  • OFA overfire air
  • SCR Selective Catalytic Reduction
  • AR Advanced Reburning
  • SNCR Selective Non-Catalytic Reduction
  • SCR is the commercial technology with the highest NO x control efficiency.
  • NO x is reduced by reactions with nitrogenous reducing agents (N-agents) such as ammonia, urea, etc., on the surface of a catalyst.
  • N-agents nitrogenous reducing agents
  • the SCR systems are typically positioned at a temperature of about 700 0 F in the exhaust stream.
  • SCR can achieve 80% NO x reduction, it is far from an ideal solution for NO x control because the size of the catalyst bed can be quite large and expensive to implement.
  • catalyst deactivation techniques typically limit the catalyst life for coal-fired applications and the spent catalysts are toxic and pose disposal problems.
  • SNCR processes involve the use of N-agents that form NH 1 radicals which react with NO. Under ideal laboratory conditions, SNCR is very effective; however, in practical, full-scale installations, the non-uniformity of the temperature profile, difficulties of mixing the N-agent across the full combustor cross section, limited residence time for reactions, and ammonia slip (unreacted N-agent) limit the effectiveness of SNCR.
  • Thermal DeNO x processes are known in which ammonia is injected into combustion flue gases containing NO and oxygen at temperatures between about 1,500 and 2,000 0 F. In such processes, a series of chemical reactions occur and NO is converted to molecular nitrogen. The reaction is believed to start with formation Of NH 2 radicals by reaction of ammonia with OH, O or H atoms.
  • urea it is also known to add urea to combustion flue gases.
  • the urea is rapidly thermally decomposed into NH 3 and HNCO and the HNCO reacts with radicals to form NH 2 or NCO.
  • NH 2 radicals can remove NO or the NCO radicals can remove NO to form N 2 and then CO and N 2 O molecules are oxidized by OH and H, respectively.
  • Rebuming is a method of controlling NO x emissions that involves fuel staging.
  • the main portion of the fuel (80-90%) is fired through conventional burners with a normal amount of air (about 10% excess) in a main combustion zone.
  • the combustion process forms a definite amount of NO x .
  • the rest of the fuel (the reburning fuel) is added at temperatures of about 2,000-2,600 0 F into the secondary combustion zone, called the reburning zone, to maintain a fuel-rich environment. In this reducing atmosphere both NO x formation and NO x removal reactions occur.
  • Advanced Reburning is a process that integrates reburning and SNCR.
  • an N-agent is injected along with the OFA, and the reburning system is adjusted to optimize NO x reduction by the N-agent.
  • the CO level is controlled and the temperature window for effective SNCR chemistry is considerably broadened.
  • the NO x reduction achieved from the N-agent injection is increased.
  • the present invention provides a method of reducing NO x emissions in combustion systems that burn carbonaceous materials which involves the chemical pretreatment of the carbonaceous materials.
  • the present invention provides a method of reducing NO x emissions in combustion systems that burn carbonaceous materials which method involves the steps of: a) providing a source of carbonaceous material particles; b) substantially uniformly distributing vanadium on the surfaces of the carbonaceous material particles; c) substantially uniformly distributing a source of titanium on the surfaces of the carbonaceous material particles; d) distributing a source of ammonia on the surfaces of the carbonaceous material particles; and e) combusting the carbonaceous material particles treated in steps b), c) and d) in a combustor.
  • the present invention further provides carbonaceous material which is treated so as to reduce NO x emissions when combusted in a combustor, the carbonaceous material includes: particles of carbonaceous material in which the surfaces of the individual particles are substantially uniformly coated with vanadium and a source of titanium.
  • Figure 1 is a flowchart of one embodiment of the method according to the present invention.
  • FIG. 2 is a flowchart of another embodiment of the method according to the present invention.
  • FIG. 3 is a flowchart of another embodiment of the method according to the present invention.
  • the present invention is directed to a method of reducing NO x emissions in combustion systems that burn carbonaceous materials which involves the chemical pretreatment of the carbonaceous materials.
  • the method is particularly suitable for treating coal used in furnaces in the power production industry, but is equally applicable for treating other carbonaceous materials used in other combustion systems.
  • Examples of carbonaceous materials include coal, coal fines, coke, coke breeze, coke fines, revert materials and mixtures thereof.
  • the treated carbonaceous materials of the present invention can be produced in the form of individual particles, agglomerated particles, pelletized or briquetted materials, or any convenient form that can be fed into a combustion system such as a furnace, boiler, etc.
  • the carbonaceous material is treated with vanadium, titanium and ammonia.
  • the treatment involves preparing a suitable slurry or suspension or emulsion or solution of the vanadium, titanium and ammonia, separately or in combination, and applying the suspension or emulsion or solution to the carbonaceous material particles so that at least the vanadium and titanium are uniformly distributed on the surfaces of the particles.
  • the treated carbonaceous material particles can be pelletized or briquetted, if desired, and otherwise stored or used immediately.
  • the vanadium, titanium and ammonia can be used in combination with conventional coal binders and coal binder compositions and agglomerating compositions, including the emulsion disclosed in U.S. Patent No. 6,530,966 to Kriech et al.
  • the use of the vanadium and titanium according to the present invention is different than NO x reduction methods such as SCR that reduce NO x after the NO x is formed.
  • the vanadium and titanium work as NO x is formed rather than after NO x is formed. This is in part accomplished by providing the vanadium and titanium close to the reductant, i.e. by uniformly distributing the vanadium and titanium on the carbonaceous material particles.
  • This uniform distribution of the vanadium and titanium can be accomplished by incorporating the vanadium and titanium into suitable emulsions, slurries, suspensions, solutions, etc. and physically applying, i.e. coating, the carbonaceous material particles with the emulsions, suspensions, solutions, etc.
  • the amount of vanadium used can be from about 0.01 to about 20 parts per million (ppm) or greater. In the case of coal used in power plants, the amount of vanadium can be from about 0.01 to about 20 ppm, but can be greater than 20 ppm.
  • the titanium can be provided as a suspension of TiO 2 in water in an amount of from about 0.01 to about 0.2 wt. % of the carbonaceous material.
  • the ammonia can be provided in any suitable form including ammonia, urea, ammonium sulfate, hydrazine, ammonium bisulfite, ammonium bisulfate, ammonium formate, ammonium carbonate, ammonium bicarbonate, biuret, triuret, ammelide, and mixtures thereof.
  • a particular source of ammonia that has been determined to be useful for purposes of the present invention is ammonium acetate because ammonium acetate is easy to disperse and does not have an objectionable odor.
  • the source of ammonia should be added so that there is one molecule of ammonia for every molecule Of NO x that is anticipated to be produced. In the case of using ammonium acetate from about 0.05 to about 0.6 wt.% of ammonium acetate was used based upon the weight of the carbonaceous material.
  • FIG. 1 is a flowchart of one embodiment of a method according to the present invention.
  • the carbonaceous material 1 e.g. coal is first contacted with vanadium 2 in mixer/blender 3. Thereafter, the carbonaceous material is contacted with a source of titanium 4 in mixer/blender 5. Thereafter, the carbonaceous material is contacted with a source of ammonia 6 in mixer/blender 7. After treatment, the treated carbonaceous material is fed into combustor 8 (or stored and later fed into combustor 8).
  • the mixers/blenders used in the treating process can be any conventional type of mixer, blender, mill, contacting apparatus, etc. that is capable of uniformly distributing the treating components, i.e. the vanadium, titanium and ammonia, on the surface of the carbonaceous material particles.
  • the combustor 8 in Fig. 1 can be a furnace, boiler, or any combustion system in which carbonaceous materials such as coal is combusted.
  • Examples of combustors include power plant furnaces, steel production furnaces, heat treatment furnaces, industrial boiler furnaces, and other carbonaceous fired furnaces, including those of steam powered vessels.
  • coal as a carbonaceous material
  • about 0.01 to about 20 ppm of vanadium (per parts of coal) were added to an emulsion that was formed by emulsifying a distillable liquid petroleum hydrocarbon with a surfactant and about 25-75 wt. % water (based on the emulsion).
  • the emulsion which is described in U.S. Patent No. 6,530,966 to Kriech et al., was provided to mixer/blender 3 in a suitable amount to coat the surface of the individual coal particles.
  • TiO 2 titanium dioxide
  • FIG. 2 is a flowchart of another embodiment of the method according to the present invention.
  • the titanium 2 and ammonia 6 are combined together, e.g. in a suspension or slurry with carbonaceous material particles 1 in mixer/blender T after the carbonaceous material particles with vanadium 2 in mixer/blender 3.
  • Figure 3 is a flowchart of another embodiment of the method of the present invention.
  • the vanadium 2 and titanium 4 are combined together, e.g. in an emulsion with the carbonaceous material particles 1 in mixer/blender 3 ' prior to contacting the carbonaceous material particles with ammonia 6 in mixer/blender 8.
  • both the vanadium and titanium should be in intimate contact with the surface of the carbonaceous material particles. Accordingly, the process illustrated in Fig. 3 first contacts the carbonaceous material particles with the vanadium and titanium before contacting the carbonaceous material particles with the ammonia.
  • the vanadium, titanium and ammonia could be combined together in an emulsion or suspension and applied to the carbonaceous material particles.
  • the treated carbonaceous materials can be used (combusted) immediately after treatment.
  • the treated carbonaceous material can be stored or pelletized or briquetted or formed into agglomerates using any conventional techniques, including the use of binders.
  • a titanium dioxide suspension of 50% weight titanium in water was prepared and mixed at 0.2% by weight (0.1% TiO 2 on coal) through the pugmill with the previously treated coal.
  • the finished mixture (treated coal) was then combusted in a power plant.
  • the power plant's NOx emissions were monitored during the combustion of the treated coal.
  • the test results found that NOx emissions dropped by 21% during the test burn from 0.313 lbs of NOx/million BTU's to 0.247 lbs/million BTU's.
  • the present method of decreasing the concentration of nitrogen oxides in flue gases emitted into the atmosphere from combustion systems that burn carbonaceous materials does not require the installation of auxiliary treatment equipment to existing combustors. Moreover, the equipment needed to pretreat the carbonaceous materials is relatively inexpensive and easy to operate.

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Treating Waste Gases (AREA)
  • Catalysts (AREA)

Abstract

L'invention porte sur un procédé de diminution de la concentration d'oxyde d'azote dans des gaz de carneau rejetés dans l'atmosphère à partir de systèmes de combustion qui brûlent des matériaux carbonés, consistant à soumettre à un traitement préalable des particules de matériau carboné avec du vanadium, du titane et de l'ammoniac. En ce qui concerne les particules de charbon, le vanadium, le dioxyde de titane et l'acétate d'ammonium servent à revêtir les particules de charbon. Le vanadium et le dioxyde de titane sont appliqués sous la forme de revêtements sensiblement uniformes sur des surfaces de particules de charbon par incorporation du vanadium et du dioxyde de titane dans des émulsions et des suspensions.
PCT/US2005/028030 2004-08-05 2005-08-05 Reduction d'oxyde d'azote dans les gaz de carneau de combustion Ceased WO2006017801A2 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US59911104P 2004-08-05 2004-08-05
US60/599,111 2004-08-05

Publications (2)

Publication Number Publication Date
WO2006017801A2 true WO2006017801A2 (fr) 2006-02-16
WO2006017801A3 WO2006017801A3 (fr) 2006-11-23

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WO (1) WO2006017801A2 (fr)

Families Citing this family (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
ITBO20070505A1 (it) * 2007-07-20 2009-01-21 Samaya S R L Gruppo per l'abbattimento degli inquinanti dei gas di scarico di macchine a combustione interna
US8951487B2 (en) 2010-10-25 2015-02-10 ADA-ES, Inc. Hot-side method and system
US11298657B2 (en) 2010-10-25 2022-04-12 ADA-ES, Inc. Hot-side method and system
US8496894B2 (en) 2010-02-04 2013-07-30 ADA-ES, Inc. Method and system for controlling mercury emissions from coal-fired thermal processes
US8845986B2 (en) 2011-05-13 2014-09-30 ADA-ES, Inc. Process to reduce emissions of nitrogen oxides and mercury from coal-fired boilers
US8883099B2 (en) 2012-04-11 2014-11-11 ADA-ES, Inc. Control of wet scrubber oxidation inhibitor and byproduct recovery
US9957454B2 (en) 2012-08-10 2018-05-01 ADA-ES, Inc. Method and additive for controlling nitrogen oxide emissions

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6258336B1 (en) * 1995-06-09 2001-07-10 Gas Research Institute Method and apparatus for NOx reduction in flue gases
US6206685B1 (en) * 1999-08-31 2001-03-27 Ge Energy And Environmental Research Corporation Method for reducing NOx in combustion flue gas using metal-containing additives
US7651541B2 (en) * 2001-01-10 2010-01-26 State Line Holdings, LLC Chemical change agent

Also Published As

Publication number Publication date
US20060090678A1 (en) 2006-05-04
WO2006017801A3 (fr) 2006-11-23

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