Fuel Tech, Inc.

Kent W Schulz

Ian Saratovsky

Christopher R Smyrniotis

Emelito P Rivera

Vasudeo S Gavaskar

Mingming Fang

Scott Bohlen

William H Sun

J David Martin

Chrisopher R Smyrniotis

Glenn Brewer

The description relates to a process for reducing acid plume from stacks from coal-fired combustors operating at varying loads, which have typically been treated by back-end calcium carbonate (limestone) which has not been able to effectively control visible acid plume as power is ramped up from low load. According to the process, as high sulfur and high iron coals are burned in a combustor, magnesium hydroxide slurry is introduced into hot combustion gases in or near the combustion zone. And, during ramp up to high load from a period of operation at low load, additional magnesium hydroxide is introduced into an intermediate-temperature zone.

Process and apparatus for reducing acid plume

The invention relates to processes for reducing emissions of hydrochloric acid (HCl) to moderate pollution to the environment and achieve regulatory compliance in a cost-effective manner. In embodiments described below, the invention deals with reducing HCl and does not require a sorbent but utilizes an aqueous composition we term a copper-bearing chloride remediator (CBCR). In one general case, the CBCR can be a member selected from the group consisting of compositions defined by the formula Cu(NH)(carbonate or lower carboxylate), wherein the lower carboxylate is selected from the group consisting of formate, acetate and propionate, x is an integer from 0 to 4, y is an integer from 0 to 2, and x+y is equal to or greater than 1.

Process for hydrochloric acid mediation

Dry processes, apparatus, compositions and systems are provided for reducing emissions of sulfur oxides, and sulfur dioxide in particular, and/or HCl and/or Hg in a process employing a combination of a lime-based sorbent, in particular hydrated lime and/or dolomitic hydrated lime, and a sorbent doping agent administered to achieve coverage of a three-dimensional cross section of a passage carrying SOand/or HCl and/or Hg-containing gases with a short but effective residence time at a temperature effective to provide significant sulfur dioxide and/or HCl and/or Hg reductions with high rates of reaction and sorbent utilization. The once-through, dry process can advantageously introduce the sorbent and sorbent doping agent dry or preferably as a slurry to enable uniform treatment. Preferred sorbent doping agents include water-soluble or water-dispersible copper and/or iron compositions which can be heated to an active form in situ by the flue gases being treated.

Process for sulfur dioxide, hydrochloric acid and mercury mediation

The description relates to reducing hydrochloric acid in cement kilns. In one aspect, an aqueous copper-based chloride remediator is introduced into contact with combustion gases from a cement kiln. Injection is made into a defined introduction zone under conditions effective for HCl emissions control wherein the temperature is within the range of from 300&#xb0; F. to 800&#xb0; F., preferably from 550&#xb0; F. to 750&#xb0; F. The resulting gases are discharged from the defined zone following sufficient reaction time to reduce the HCl concentration in the gases.

Reducing hydrochloric acid in cement kilns

The description relates to production of fly ash with properties suitable for use in Portland cement. The fly ash compositions will contain coal ash, water-insoluble copper compositions and metallic mercury adsorbed onto ash particles. In one aspect, the coal ash composition will have a total mercury content of from 0.1 to 2.0 ppm and the water-soluble mercury is less than 20% of the total mercury content. The process entails combusting coal to produce hot combustion gases containing fly ash, CO, chlorine, and mercury, cooling the combustion gases and introducing into the combustion gases at a temperature of less than 1000&#xb0; F., preferably within the range of from about 250&#xb0; to about 900&#xb0; F., a copper-based chloride remediator (CBCR), and collecting the fly ash which comprises insoluble copper compositions and water insoluble mercury compositions.

Ash compositions recovered from coal combustion gases having reduced emissions of HCI and/or mercury

HCl and sulfur oxides are reduced by treating combustion gases with an aqueous copper compound referred to as copper-based chloride remediator (CBCR). The process is preferably implemented by identifying locations within a combustor for feeding the CBCR, determining the physical form and injection parameters for the CBCR and injecting the CBCR under conditions effective to reduce HCl and/or sulfur oxides. Effective temperatures for introducing the CBCRs can be from about 250&#xb0; to 900&#xb0; F. for HCl and up to about 2200&#xb0; F. for sulfur oxides. Preferred CBCRs include copper and an ammonia moiety. One composition is copper diammonium diacetate, empirical formula of CHCuNO. CBCR compositions are not sorbents and chemically convert HCl from a gaseous to a solid form.

Processes, apparatus, compositions and systems for reducing emissions of HCI and/or sulfur oxides

The operation of wet scrubbers, especially those based on calcium carbonate, is improved by reducing the quantities of soluble chlorides in the combustion gases fed to the scrubbers. HCl in the combustion gases is converted to a solid copper chloride and removed before the chloride reaches the scrubber. Combustion gases are treated with an aqueous copper compound referred to as copper-bearing chloride remediator (CBCR). Effective temperatures for introducing the CBCRs are preferably within the range of from about 250&#xb0; to 900&#xb0; F. Among the more preferred CBCRs are copper compositions including copper, an organic moiety and/or an ammonia moiety.

Process and apparatus for improving the operation of wet scrubbers

Dry processes, apparatus, compositions and systems are provided for reducing emissions of mercury and optionally sulfur oxides and/or HCl. In an embodiment the copper-based mercury remediation composition comprises a copper ammonium complex having an empirical formula of CHCuNOor any of the other materials described, which include compositions defined by the formula Cu(NH)(lower carboxylate), wherein the lower carboxylate is selected from the group consisting of formate, acetate and propionate, x is an integer from 0 to 4, y is an integer from 0 to 2, and x+y is equal to or greater than 1. Sulfur oxides and/or HCl can be additionally reduced by introduction of dolomite hydrate sorbent, and additional mercury remediation chemicals as manganese oxides can be employed. The treated gas stream is treated with a particulate removal device.

Dry processes, apparatus compositions and systems for reducing mercury, sulfur oxides and HCl

Dry processes, apparatus, compositions and systems are provided for reducing emissions of sulfur oxides, and sulfur dioxide in particular, and/or HCl in a process employing a combination of a dolomite hydrate sorbent and a sorbent doping agent administered to achieve coverage of a three-dimensional cross section of a passage carrying SOand/or HCl &#x2014;containing gases with a short but effective residence time at a temperature effective to provide significant sulfur dioxide and/or HCl reductions with high rates of reaction and sorbent utilization. The once-through, dry process can advantageously introduce the sorbent and sorbent doping agent dry or preferably as a slurry to enable uniform treatment. Preferred sorbent doping agents include water-soluble or water-dispersible copper and/or iron compositions which can be heated to an active form in situ by the flue gases being treated.

Dry processes, apparatus, compositions and systems for reducing sulfur oxides and HCI

A slag and corrosion control process is described. The process entails: identifying the location of at least one slagging problem area in a boiler; introducing a slag control chemical comprising magnesium oxide or hydroxide into combustion gases in a location identified as having a slagging problem; identifying the location of at least one corrosion problem area in a boiler; and introducing a corrosion control chemical comprising a sulfate salt, bisulfite salt, sulfuric acid, or sulfur into combustion gases in a location identified as having a corrosion problem. In operation, these slag deposits will be sufficiently friable to be removed by relatively moderate application of physical energy, thus saving time and reducing any damage to the tubes by the cleaning process. The slag deposits are less voluminous and less in weight and are removed quickly. It is an advantage of the invention that slag can be removed with little or no shut down of a boiler.

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Geneva, IL, United States of America

Kent W Schulz