Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
  • B01D53/34—Chemical or biological purification of waste gases
  • B01D53/46—Removing components of defined structure
  • B01D53/64—Heavy metals or compounds thereof, e.g. mercury
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
  • B01D53/34—Chemical or biological purification of waste gases
  • B01D53/74—General processes for purification of waste gases; Apparatus or devices specially adapted therefor
  • B01D53/86—Catalytic processes
  • B01D53/8668—Removing organic compounds not provided for in B01D53/8603 - B01D53/8665
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D2251/00—Reactants
  • B01D2251/40—Alkaline earth metal or magnesium compounds
  • B01D2251/404—Alkaline earth metal or magnesium compounds of calcium
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D2251/00—Reactants
  • B01D2251/60—Inorganic bases or salts
  • B01D2251/602—Oxides
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D2251/00—Reactants
  • B01D2251/60—Inorganic bases or salts
  • B01D2251/606—Carbonates
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D2251/00—Reactants
  • B01D2251/90—Chelants
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D2252/00—Absorbents, i.e. solvents and liquid materials for gas absorption
  • B01D2252/20—Organic absorbents
  • B01D2252/205—Other organic compounds not covered by B01D2252/00 - B01D2252/20494
  • B01D2252/2056—Sulfur compounds, e.g. Sulfolane, thiols
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D2257/00—Components to be removed
  • B01D2257/30—Sulfur compounds
  • B01D2257/302—Sulfur oxides
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D2257/00—Components to be removed
  • B01D2257/60—Heavy metals or heavy metal compounds
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D2257/00—Components to be removed
  • B01D2257/60—Heavy metals or heavy metal compounds
  • B01D2257/602—Mercury or mercury compounds
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D2258/00—Sources of waste gases
  • B01D2258/02—Other waste gases
  • B01D2258/0283—Flue gases
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
  • B01D53/14—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols by absorption
  • B01D53/1493—Selection of liquid materials for use as absorbents
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
  • B01D53/34—Chemical or biological purification of waste gases
  • B01D53/46—Removing components of defined structure
  • B01D53/48—Sulfur compounds
  • B01D53/50—Sulfur oxides
  • B01D53/501—Sulfur oxides by treating the gases with a solution or a suspension of an alkali or earth-alkali or ammonium compound
  • B01D53/502—Sulfur oxides by treating the gases with a solution or a suspension of an alkali or earth-alkali or ammonium compound characterised by a specific solution or suspension
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
  • B01D53/34—Chemical or biological purification of waste gases
  • B01D53/74—General processes for purification of waste gases; Apparatus or devices specially adapted therefor
  • B01D53/77—Liquid phase processes
  • B01D53/78—Liquid phase processes with gas-liquid contact

Definitions

• This invention relates to the treatment of flue gas wet scrubber processes. More particularly, the invention relates to the method of capture of selenium from flue gases by flue gas wet scrubber processes. The invention also relates to minimizing corrosion in flue gas wet scrubber processes.
• the primary gas emissions are criteria pollutants (e.g. sulfur dioxide, nitrogen dioxides, particulate material, and carbon monoxide). About two thirds of all sulfur dioxide and a quarter of the nitrogen dioxide in the atmosphere is attributable to electric power generation achieved by burning coal and other fuels.
• criteria pollutants e.g. sulfur dioxide, nitrogen dioxides, particulate material, and carbon monoxide.
• Secondary emissions depend on the type of coal or fuel being combusted but include as examples mercury, selenium, arsenic, and boron.
• Selenium chemistry is similar to sulfur chemistry where selenium exists in flue gas as selenium dioxide and immediately converts to the selenite ion upon absorption into the liquid stream within the flue gas wet scrubber process. While certain chemistries have been known to successfully capture heavy metal cations, such chemistries would not expect to be effective at reducing selenium concentrations in liquid waste generated from flue gas wet scrubber processes.
• flue gas wet scrubber processes can fail from corrosion.
• a metallurgy designated as 2205 alloy stainless steel has become popular in the industry due to its low cost and high chloride resistance.
• these scrubbers will operate with 10 to 12,000 ppm chloride concentration in their liquors.
• flue gas wet scrubbers constructed of 2205 alloy have experienced increased levels of pitting and localized corrosion, resulting in forced, unscheduled unit shutdowns and expensive repairs.
• PAP systems apply an electrical potential across the metal surface in an effort to control and reduce corrosion. This method has been successful, but it requires the installation of electrodes into the scrubber and the constant application of electrical potential and current. It also suffers from being applicable to only wet surfaces within the scrubbers.
• the invention is directed toward a method for removing selenium from flue gas in a flue gas wet scrubber process.
• the invention is also directed toward a method for minimizing corrosion in a flue gas wet scrubber process.
• Each method comprises the steps of burning fuel, thereby producing flue gas; and passing the flue gas into the flue gas wet scrubber process comprising a polydithiocarbamic compound of at least one polythiocarbamic material.
• the method comprises the steps of burning fuel, thereby producing flue gas; and passing the flue gas into the flue gas wet scrubber process comprising a polymer derived from at least two monomers: acrylic-x and an alkylamine, and wherein said acrylic-x has the following formula:
• X OH and salts thereof or NHR 2 and wherein R 1 and R2 is H or an alkyl or aryl group, wherein the molecular weight of said polymer is between 500 to 200,000, and wherein said polymer is modified to contain a functional group capable of scavenging at least one metal- comprising composition.
• the method may comprise a combination of the polydithiocarbamic compound and the polymer derived from acrylic-x and alkylamine.
• the polydithiocarbamic compound may be the polymer.
• the invention may further comprise a transition metal salt, which may be an iron salt.
• the invention is directed toward a composition of matter comprising a polydithiocarbamic compound of at least one polythiocarbamic material; and a transition metal salt.
• the invention is directed toward a composition of matter comprising a polymer derived from at least two monomers: acrylic-x and an alkylamine, and wherein said acrylic-x has the following formula:
• composition may be comprised additionally of a polydithiocarbamic compound of at least one polythiocarbamic material, and the polymer may be comprised of a polydithiocarbamic compound.
• FIG. 1 is a graph demonstrating the positive effects of Chemistry 1 on decreased selenium concentration and decreased oxidation-reduction potential in the aqueous phase of a flue gas wet scrubber process
• FIG 2 is a graph demonstrating the positive effects of Chemistry 2 on decreased selenium concentration and decreased oxidation-reduction potential in the aqueous phase of a flue gas wet scrubber process.
• the present invention documents the unexpected results obtained from the use of certain chemistries, which unexpectedly reduced selenium concentration nearly ten-fold in water phase blowdown of a flue gas wet scrubber process. While not wishing to be bound by a particular mechanism, through the addition of the chemistries within the flue gas wet scrubber process, the chemistries have the opportunity to capture the selenite before it has a chance to further oxidize to selenate. Selenate is difficult to remove from the water phase. Additionally, the chemistries have also proved to be advantageous in minimizing corrosion in flue gas wet scrubber systems. Particularly, the chemistries have helped minimize corrosion in flue gas wet scrubber systems that are constructed of 2205 alloy. It was
• ORP oxidation-reduction potential
• ORP is not exactly the same as corrosion potential, the two numbers track each other.
• ORP is an indication of the oxidative or reductive nature of the environment.
• Corrosion potential is the oxidative or reductive nature at the surface of a specific metal. Therefore, the corrosion potential generally reflects the ORP, but the two values are not the same. However, the ORP trend would typically indicate the corrosion potential trend.
• the flue gas wet scrubber process comprises a wet flue gas desulfurizer process.
• the flue gas wet scrubber process employs equipment comprising 2205 alloy.
• the fuel is selected from the group consisting of coal, reclailmed coal, natural gas, industrial waste, a gasified waste product, biomass, and any combination thereof.
• Chemistry 1 is a water-soluble ethylene dichloride ammonia polymer having a molecular weight of from 500 to 10,000, which contains from 5 to 55 mole% of dithiocarbamate salt groups.
• Chemistry 1 may additionally comprise a transition metal salt, which may be an iron salt.
• the positive effects of Chemistry 1 on both reduction of selenium in the aqueous phase and reduction in oxidation-reduction potential are shown in FIG. 1.
• the ethylene dichloride- ammonia polymers are prepared by the reaction of ethylene dichloride and ammonia.
• the starting ethylene dichloride-ammonia polymers generally have a molecular weight range of 500- 100,000. In a preferred embodiment the molecular weight is 1,500 to 10,000, with the most preferred molecular weight range being 1,500 to 5,000.
• the copolymer of this invention is produced using methods presented in U.S. Patent Nos. 4,731,187; 5,500,133; or 5,658,487 that are examples of said copolymers available for use in the claimed invention.
• the copolymer is produced by the reaction of the polyamines or polyimines with carbon disulfide to produce polydithiocarbamic acid or its salts. Such reaction is preferably carried out in a solvent such as water or alcohol at a temperature of from 30° and 100°C for periods of time ranging between 1 and 10 hours. Good conversion is obtained at temperatures between 40° and 70°C for 2 to 5 hours. These reaction conditions apply to the modification of ethylene dichloride-ammonia polymers described previously.
• the mole % of dithiocarbamate salt groups in the finished polymer generally is within the range of 5 to 55%.
• the preferred range is 20 to 55 mole %, with the most preferred range being about 30 to 55 mole %.
• the salts include but are not limited to alkaline and alkali earth such as sodium, lithium, potassium or calcium.
• the chemistry may include at least one transition metal salt, which may be an iron salt.
• the scrubber processes currently used in the industry include spray towers, jet bubblers, and co-current packed towers as examples. These types of air quality control devices
• AQCDs are provided as examples and are not meant to represent or suggest any limitation.
• the water-soluble copolymer may be added to virgin limestone or lime slurry prior to addition to the scrubber, the recirculation loop of the scrubber liquor, or the "low solids" return to the scrubber from the scrubber purge stream.
• the copolymer is applied at a ratio of 1 :1 to 2000:1 weight copolymer to weight of selenium being captured.
• the preferred ratio is from 5:1 to 1000: 1 and the most preferred range is from 5 : 1 to 500: 1.
• the polydithiocarbamic acid compounds may be introduced into the scrubber and thereby into the scrubber liquor via several routes.
• the following will serve as just some of the variations that are available to introduce the compounds into the scrubber liquor.
• the scrubber liquor is defined as the water-based dispersion of calcium carbonate (limestone) or calcium oxide (lime) used in a wet flue gas scrubber ("FGS," also known as a wet flue gas desulfurizer, or "FGD”) to capture SO x emissions.
• FGS wet flue gas scrubber
• FGD wet flue gas desulfurizer
• the liquor may also contain other additives such as magnesium and low-molecular weight organic acids, which function to improve the sulfur, capture.
• additive is a mixture of low-molecular weight organic acids known as dibasic acid (“DBA").
• DBA consists of a blend of adipic, succinic, and glutaric acids. Each of these organic acids can also be used individually. In addition, another low- molecular weight organic acid that can be used to improve sulfur capture in a wet scrubber is formic acid. Finally, the scrubber liquor will also contain byproducts of the interaction between the lime or limestone and sulfur species, which leads to the presence of various amounts of calcium sulfite or calcium sulfate.
• the scrubber liquor includes but is not limited to the make-up liquor, return liquor, the reclaimed liquor, virgin liquor and liquor injected directly into flue gases.
• Another addition point for the polydithiocarbamic compounds of this invention to the wet scrubber is via the "low solids" liquor return.
• a portion of the liquor is usually continuously removed from the scrubber for the purpose of separating reaction byproducts from unused lime or limestone.
• One means of separation that is currently used is centrifugation. In this process the scrubber liquor is separated into a "high solids” and “low solids” stream. The high solids stream is diverted to wastewater processing. The low solids fraction returns to the wet scrubber and can be considered “reclaimed” dilute liquor.
• the polydithiocarbamic acid compounds of this invention can conveniently be added to the reclaimed low solids stream prior to returning to the scrubber.
• Virgin liquor is the water-based dispersion of either lime or limestone prior to exposure to flue gas and is used to added fresh lime or limestone while maintaining the scrubber liquor level and efficiency of the wet FGD. This is prepared by dispersing the lime or limestone in water.
• the polydithiocarbamic acid compounds can be added either to the dispersion water or the virgin liquor directly.
• polydithiocarbamic acid compounds can be made in any of these locations, wholly or fractionally (i.e. a single feed point or multiple feed points), including but not limited to the make-up water for the lime or limestone slurry or the scrubber liquor.
• composition comprising a polymer derived from at least two monomers: acrylic-x and an alkylamine, wherein said acrylic-x has the following formula:
• X OR, OH and salts thereof, or NHR 2 and wherein R 1 and R2 is H or an alkyl or aryl group, wherein R is an alkyl or aryl group, wherein the molecular weight of said polymer is between 500 to 200,000, and wherein said polymer is modified to contain a functional group capable of scavenging one or more compositions containing one or more metals.
• the metals can include zero valent, monovalent, and multivalent metals.
• the metals may or may not be ligated by organic or inorganic compounds.
• the metals can be radioactive and nonradioactive. Examples include, but are not limited to, transition metals and heavy metals. Specific metals can include, but are not limited to: copper, nickel, zinc, lead, mercury, cadmium, silver, iron, manganese, palladium, platinum, strontium, selenium, arsenic, cobalt and gold.
• the molecular weight of the polymers can vary.
• the target species/application for the polymers can be one consideration.
• Another factor can be monomer selection.
• Molecular weight can be calculated by various means known to those of ordinary skill in the art. For example, size exclusion chromatography, as discussed in the examples below can be utilized.
• molecular weight When molecular weight is mentioned, it is referring to the molecular weight for the unmodified polymer, otherwise referred to as the polymer backbone.
• the functional groups that are added to the backbone are not part of the calculation. Thus the molecular weight of the polymer with the functional groups can far exceed the molecular weight range.
• the molecular weight of the polymer is from 1,000 to 16,000.
• the molecular weight of said polymer is from 1,500 to 8,000.
• the functional group contains a sulfide containing chemistry.
• the functional group is a dithiocarbamate salt group.
• the functional groups are at least one of the following :alkylene phosphate groups, alkylene carboxylic acids and salts thereof, oxime groups, amidooxime groups, dithiocarbamic acids and salts thereof, hydroxamic acids, and nitrogen oxides.
• the molar amounts of the functional group relative to the total amines contained in the unmodified polymer can vary as well.
• the reaction of 3.0 molar equivalents of carbon disulfide to a 1.0: 1.0 mole ratio acrylic acid / TEPA copolymer, which contains 4 molar equivalents of amines per repeat unit after polymerization will result in a polymer that is modified to contain 75 mole % dithiocarbamate salt group.
• 75 % of the total amines in the unmodified polymer has been converted to dithiocarbamate salt groups.
• the polymer has between 5 to 100 mole % of the dithiocarbamate salt group. In a further embodiment, the polymer has from 25 to 90 mole % of the dithiocarbamate salt group. In yet a further embodiment, the polymer has from 55 to 80 mole % of the
• Monomer selection will depend on the desired polymer that one of ordinary skill in the art would want to make .
• the alkylamines may vary in kind.
• the alkylamine is at least one of the following: an ethyleneamine, a polyethylenepolyamine, ethylenediamine (EDA), diethylenetriamine (DETA),
• TETA triethylenetetraamine
• TEPA tetraethylenepetamine
• PEHA pentaethylenehexamine
• the acrylic-x monomer group can vary as well.
• the acrylic-x is at least one of the following: methyl acrylate, methyl methacrylate, ethyl acrylate, and ethyl methacrylate, propyl acrylate, and propyl methacrylate.
• the acrylic-x is at least one of the following: acrylic acid and salts thereof, methacrylic acid and salts thereof, acrylamide, and methacrylamide.
• the molar ratio between monomers that make up the polymer, especially acrylic-x and alkylamine can vary and depend upon the resultant polymer product that is desired.
• the molar ratio used is defined as the moles of acrylic-x divided by the moles of alkylamine.
• the molar ratio between acrylic-x and alkylamine is from 0.85 to 1.5.
• the molar ratio between acrylic-x and alkylamine is from 1.0 to
• the acrylic-x is an acrylic ester and the alkylamine is PEHA or TEPA or DETA or TETA or EDA.
• the molar ratio between acrylic-x and alkylamine is from 0.85 to 1.5.
• the molecular weight can encompass ranges: 500 to 200,000, 1,000 to 16,000, or 1,500 to 8,000.
• the acrylic ester can be at least one of the following: methyl acrylate, methyl methacrylate, ethyl acrylate, and ethyl methacrylate, propyl acrylate, and propyl methacrylate, which is combined with at least one of the alklyamines, which includes PEHA or TEPA or DETA or TETA or EDA.
• the resulting polymer is modified to contain the following ranges of dithiocarbamate salt groups: 5 to 100 mole %, 25 to 90 mole %, 55 to 80 mole %.
• the acrylic-x is an acrylic amide and the alkylamine is TEPA or DETA or TETA or EDA.
• the molar ratio between acrylic-x and alkylamine is from 0.85 to 1.5.
• the molecular weight can encompass ranges: 500 to 200,000, 1,000 to 16,000, or 1,500 to 8,000.
• the acrylic amide can be at least one or a combination of acrylamide and methacrylamide, which is combined with at least one of the alklyamines, which includes PEHA or TEPA or DETA or TETA or EDA.
• the resulting polymer is modified to contain the following ranges of dithiocarbamate salt groups: 5 to 100 mole %, 25 to 90 mole %, or 55 to 80 mole %.
• the acrylic-x is an acrylic acid and salts thereof and the alkylamine is PEHA or TEPA or DETA or TETA or EDA.
• the molar ratio between acrylic-x and alkylamine is from 0.85 to 1.5.
• the molecular weight can encompass ranges: 500 to 200,000, 1,000 to 16,000, or 1,500 to 8,000.
• the acrylic acid can be at least one or a combination of acrylic acid or salts thereof and methacrylic acid or salts thereof, which is combined with at least one of the alklyamines, which includes TEPA or DETA or TETA or EDA.
• the resulting polymer is modified to contain the following ranges of dithiocarbamate salt groups: 5 to 100 mole %, 25 to 90 mole %, or 55 to 80 mole %.
• Additional monomers can be integrated into the polymer backbone made up of constituent monomers acrylic-x and alkylamine.
• a condensation polymer reaction scheme can be utilized to make the basic polymer backbone chain.
• Various other synthesis methods can be utilized to functionalize the polymer with, for example, dithiocarbamate and/or other non-metal scavenging functional groups.
• One of ordinary skill in the art can functionalize the polymer without undue experimentation.
• composition of the present invention can be formulated with other polymers such as those disclosed in U.S. Patent No. 5,164,095, herein incorporated by reference, specifically, a water soluble ethylene dichloride ammonia polymer having a molecular weight of from 500 to 100,000 which contains from 5 to 50 mole % of dithiocarbamate salt groups.
• the molecular weight of the polymer is from 1500 to 10,000 and contains 15 to 50 mole % of dithiocarbamate salt groups.
• the molecular weight of the polymer is from 1500 to 5000 and contains 30 to 55 mole % of dithiocarbamate salt groups.
• composition of the present invention can be formulated with other small molecule sulfide precipitants such as sodium sulfide, sodium hydrosulfide, TMT-15® (sodium or calcium salts of trimercapto-S-triazine; Evonik Industries Corporation 17211 Camberwell Green Lane, Houston, TX 77070, USA), dimethyldithiocarbamate and diethyldithiocarbamate.
• TMT-15® sodium or calcium salts of trimercapto-S-triazine
• trimercapto-S-triazine Evonik Industries Corporation 17211 Camberwell Green Lane, Houston, TX 77070, USA
• the dosage of the disclosed polymers for use may vary. The calculation of dosage amounts can be done without undue experimentation.
• Process medium quality and extent of process medium treatment are a couple of factors that can be considered by one of ordinary skill in the art in selecting dosage amount.
• Ajar test analysis is a typical example of what is utilized as a basis for determining the amount of dosage required to achieve effective metals removal in the context of a process water medium, e.g. wastewater.
• the amount of modified polymer of the invention capable of effectively removing metals from contaminated waters is preferably within the range of 0.2 to 2 moles of dithiocarbamate per mole of metal. More preferably, the dosage is 1 to 2 moles of dithiocarbamate per mole of metal contained in the water. According to one embodiment of the invention, the dosage of metal removal polymer required to chelate and precipitate 100 ml of 18 ppm soluble copper to about 1 ppm or less was 0.011 gm (11.0 mg) of polymer. The metal polymer complexes formed are self-flocculating and quickly settle. These fiocculants are easily separated from the treated water.
• the polymer in the context of applying the polymer to a gas system, such as a flue gas, can be dosed incrementally and capture rates for a particular metal, e.g. such as mercury, can be calculated by known techniques in the art.
• a particular metal e.g. such as mercury
• the present disclosure also provides for a method of removing selenium from a medium containing selenium which comprises the steps of: (a) treating said medium containing metals with a composition comprising a polymer derived from at least two monomers: acrylic-x and an alkylamine, wherein said acrylic-x has the following formula:
• X OR, OH and salts thereof, or NHR 2 and wherein R 1 and R2 is H or an alkyl or aryl group, wherein R is an alkyl or aryl group, wherein the molecular weight of said polymer is between 500 to 200,000, and wherein said polymer is modified to contain a functional group capable of scavenging one or more compositions containing one or more metals; and (b) collecting said treated metals.
• compositions as described above are incorporated into this section and can be applied within the claimed methodologies encompassed by this invention.
• Mediums containing selenium can vary and include at least one of the following wastewater streams, liquid hydrocarbonaceous streams, flue gas streams, flyash, and other particulate matter.
• Various processing steps can be coupled with metals removal, including, but not limited to filtration steps and/or air quality control devices, e.g. baghouses and electrostatic precipitators and other air quality control devices.
• Mediums containing a liquid phase medium/a medium containing a liquid phase are one target for the claimed invention.
• the medium is a process stream containing water, e.g. wastewater or wastewater from a power plant or industrial setting (power plant, mining operation, waste incineration, and/or manufacturing operation).
• a process stream containing water e.g. wastewater or wastewater from a power plant or industrial setting (power plant, mining operation, waste incineration, and/or manufacturing operation).
• the medium is a liquid hydrocarbonaceous stream common in petroleum refining processes or petrochemical processes.
• examples include streams from these processes that contain petroleum hydrocarbons such as petroleum hydrocarbon feedstocks including crude oils and fractions thereof such as naphtha, gasoline, kerosene, diesel, jet fuel, fuel oil, gas oil vacuum residual, etc or olefinic or napthenic process streams, ethylene glycol, aromatic hydrocarbons, and their derivatives.
• chemistries, flocculants and/or coagulants can be utilized in conjunction with the chemistry encompassed by this invention.
• the chemistries applied to a medium containing metals can vary, including, the addition of at least one of the following: cationic polymers, anionic polymers, amphoteric polymers, and zwitterionic polymers.
• the method of this invention further comprises an additional treatment to the process stream with a complexing amount of a water soluble ethylene dichloride ammonia polymer having a molecular weight of from 500 to 100,000 which contains 5 to 50 mole % of dithiocarbamate salt groups to form a complex of these metals, e.g. heavy metals.
• the molecular weight of the polymer is from 1500 to 10,000 and contains 15 to 50 mole % of dithiocarbamate salt groups.
• the molecular weight of the polymer is from 1500 to 5000 and contains 30 to 55 mole % of dithiocarbamate salt groups.
• the polymer treatment and additional treatment are added in a ratio of 1 : 1.
• Mediums containing a gas phase medium/a medium containing a gas phase are another target for the claimed invention.
• processes containing a liquid and/or gas phase medium are encompassed by this invention as well.
• the medium is part of a heat generating system, e.g. a flue gas stream.
• the heat generating system is at least one of the following: a combustion system; a power plant combustion system; a coal combustion system; a waste incineration system; a kiln; a kiln for mining or cement operations; and an ore processing system.
• the method of this invention further comprises applying an oxidizing agent to a heat generating system.
• the oxidizing agent is applied prior to said polymer treatment.
• a multiphase treatment protocol for a process involves treating a gas and a liquid, e.g., one or more metals in a gas such as mercury and one or more metal in a liquid. This can involve the polymer treatment and additional treatment as described above.
• the oxidizing agent is at least one of the following: a thermolabile molecular halogen, calcium bromide, or a halogen containing compound.
• this invention further comprises applying an oxidizing agent to the flue gas; optionally wherein said oxidizing agent oxidizes a target species at a temperature of 500°C or greater or a temperature where the oxidant is capable of oxidizing molecular mercury that exists in a process that generates mercury; optionally wherein said target species is elemental mercury or derivatives thereof; and optionally wherein said oxidizing agent is at least one of the following: a thermolabile molecular halogen, calcium bromide, or a halogen containing compound.
• Mercury oxidant methodologies are described in US Patent Nos. 6,808,692 and 6,878,358, which are herein incorporated by reference.
• the polymer treatment occurs at a temperature 300°C or below, preferably 250 °C or below.
• aDTCP is a polydithiocarbamic compound of the present invention
• bFlocculant is commercially available from Nalco Company and is a very high molecular, 30mole% anionic latex polymer.
• a 2L solution was prepared by dissolving 6.7 mg of sodium selenite, Na 2 Se0 3 *5H 2 0, 14 mL of 0.141M Hg(N0 3 ) 2 and 18.4g of calcium chloride, CaCl 2 *2H 2 0.
• the resulting solution had measured concentrations of 0.037mM selenium, 1.04 ⁇ mercury and 63mM calcium chloride dehydrate.
• the zeolite was a spent commercial catalyst.
• the fly ash sample was obtained from a coal-fired power plant.
• the fly ash sample was composed of 93% ash content with 6%> residual carbon and 1% residual sulfur.
• a synthetic FGD scrubber liquor was prepared by dissolving 12.58g of calcium chloride dihydrate, CaCl 2 *2H 2 0, in 400mL of deionized water. The resulting solution was 214mM in calcium chloride dihydrate leading to 15,000ppm chloride and 8560ppm calcium in solution. The solution was split into two equal portions. To 200mL of solution was added 164 ⁇ of
• polydithiocarbamic acid compound product was a 30%> active water miscible solution.
• the two portions were agitated separately with a magnetic stir bar for 12 hours.
• the suspension was filtered using a Pall Life Sciences GN-6 Metricel 0.45 ⁇ membrane filter (P/N 63069). The filtrate was analyzed for mercury.
• a second portion, 200g, of calcium chloride dihydrate solution was treated with 82 ⁇ , of 0.61mM mercuric nitrate solution to yield a solution containing 78.3 ⁇ of ionic mercury. Again this solution was treated with 27.4g of calcium sulfate, dihydrate to yield a slurry containing 18% by weight.
• this sample was split into two solutions, the minor portion, 75g, was treated with the polydithiocarbamic acid compound product at a 5 : 1 product weight to mercury weight ratio.
• the dispersions were filtered using a Pall Life Sciences GN-6 Metricel 0.45 ⁇ membrane filter (P/N 63069). The filtrate was analyzed for mercury. The results are shown below.
• the polydithiocarbamic acid compound of this invention removes the ionic mercury from the liquid phase.
• the gypsum solids for the above samples were submitted for TGA (Thermogravimetric Analysis) in order to observe any decomposition or release of mercury. All the thermographs were identical exhibiting only the loss of associated and bound water between room temperature and 170°C. Above this temperature no further decomposition could be observed. This indicates that once the complex is formed, it does not decompose under normal FGD scrubber operation.
• TGA Thermogravimetric Analysis
• a general stock solution was prepared containing 0.214M calcium chloride dihydrate by dissolving 220g of CaCl 2 *2H 2 0 in 7L of deionized water. To this was added 74 ⁇ ⁇ of 61mM mercury nitrate solution to yield a solution containing 136 ⁇ g/L. This solution was divided into two portions. The first portion was mixed with enough calcium sulfate dihydrate to yield slurry at 18% by weight-dispersed solids. The second portion was mixed with enough calcium sulfate dihydrate to yield a 21% by weight slurry.
• DBA Dibasic Acid
• adipic acid aka hexanedioic acid
• succinic acid aka butanedioic acid
• glutaric acid aka pentaedioic acid
• a "synthetic" DBA was prepared using an equal molar ratio of adipic and succinic acids.
• the adipic acid can be obtained from Mallmckrodt Chemicals, Cat No. MK180159.
• the succinic acid can be obtained from J.T. Baker, reagent grade, Cat. No. JT0346-5.
• the solutions were spiked with the equal molar ratio acids to produce 332 and lOOppm total acid concentrations.
• the polydithiocarbamic acid compound of the current invention was added at a product to mercury weight ratio of 4.5 : 1 and 1 : 1 respectively with or without the synthetic DBA present in the slurry.
• the order of addition was kept to the following: synthetic DBA then the
• polydithiocarbamic acid compound of this invention Once the various additives have been introduced into the slurry, it is mixed for an additional 15 to 20 minutes with a magnetic stir bar. After this time, the slurry is filtered using a Pall Life Sciences GN-6 Metricel 0.45 ⁇ membrane filter (P/N 63069). The filtrate is subsequently analyzed.
• DTCP is the polydithiocarbamic acid compound of this invention. See above for the definition of synthetic DBA, aka “Syn DBA”.
• TMT-15 Three additives were tested in a bench-scale wet scrubber with a gas flow of 1-cfm.
• One additive, TMT-15 is currently used to control mercury emissions from incinerators.
• the polydithiocarbamic acid compound, sodium salt used is an embodiment of the claimed invention.
• the bench-scale unit allows for the use of a simulated flue gas composed of S0 2 , NO x ,
• HC1, C0 2 oxygen and nitrogen.
• Moisture is controlled by exposing a portion of the oxygen, carbon dioxide, and nitrogen to water saturators.
• the flue gas composition used in the study consisted of 15-25 ⁇ g/Nm 3 HgCl 2 , 12% C0 2 , 3% 0 2 , lOOOppm S0 2 , 15ppm HC1, no NO x , the balance nitrogen.
• the flow rate was 28 L/min.
• the sorbent solution or scrubber liquor was maintained at a temperature of 55°C and consisted of lOOmM sodium chloride, and lOmM sodium sulfate (initial concentration) with a pH of 5.0.
• the sulfite concentration was controlled at 5mM by the addition of hydrogen peroxide to the sorbent solution.
• the pH of the scrubber liquor was maintained by the addition of NaOH.
• the appropriate amount of additive was introduced into the scrubber liquor just prior to the injection of 0.5 ⁇ HgCl 2 as a solution of 0.5mM HgCl 2 and after the system had reached equilibrium.
• the bench-scale scrubber uses a bubbler type gas contactor.
• the gas contact vessel sits on top of the scrubber liquor reaction vessel so that the liquor returns to the reactor vessel via gravity drainage.
• the liquor is recirculated into the scrubber via a recirculation pump to maintain a constant liquid/gas ratio.
• the pH is monitored both in the scrubber and in the reaction vessel.
• the pH of the reaction vessel is maintained by addition of sodium hydroxide solution.
• the reaction vessel is mixed via magnetic stirring.
• a flow-through cell and spectrophotometer was used to monitor sulfite concentration in the scrubber liquor via a modification of a method reported by M.W. Scoggins, Analytical Chemistry, 42(9), 1091 (1970).
• the untreated unit was burning the same fuel during this commercial test.
• Chemistry 1 was applied to the treated unit. Two samples were taken during different periods of the demonstration while the technology was applied. The disclosed technology was turned off for 18 hours (i.e. Condition Additive Off shown above) prior to sampling. Then Chemistry 1 was reapplied to obtain the final condition, i.e. additive reapplied.
• Methyl Acrylate / Tetraethylenepentamine Polymer Backbone which is then functionalized with a dithiocarbamate group a.
• Methyl Acrylate / Tetraethylenepentamine Polymer Backbone Synthesis Tetraethylenepentamine (TEPA) (18.275 weight %) was charged into a glass reactor fitted with a mechanical stirrer and a condenser. While purging the headspace with nitrogen and stirring, methyl acrylate (16.636 weight %) was added dropwise over 30 min where the temperature was maintained between 25 - 31° C during the addition and for 1 h after the addition was finished. Next, a second charge of TEPA (18.275 weight %) was performed and the resulting reaction mixture was heated to 130° C.
• the second step involved adding the methyl acrylate / TEPA polymer (35.327 weight %), DI Water (28.262 weight %), and Dowfax 2A1 (0.120 weight %), Dow Chemical Company Midland, MI 48674, USA, to a round bottom flask fitted with a mechanical stirrer.
• a 50% NaOH solution (9.556 weight %) was added to the stirring reaction mixture.
• carbon disulfide (17.179 weight %>) was added drop-wise over 2 h.
• One hour within the carbon disulfide addition another amount of 50% NaOH (9.556 weight %) was charged.
• the reaction mixture was maintained at 40° C for an additional 2 h.
• the reaction was cooled to room temperature and filtered through filter paper to obtain ⁇
• Acrylic Acid / Tetraethylenepentamine Polymer Backbone which is then functionalized with a dithiocarbamate group a.
• Acrylic Acid / Tetraethylenepentamine Polymer Backbone Synthesis Tetraethylenepentamine (TEPA) (37.556 weight %) and sulfuric acid (0.199 weight %) was charged into a glass reactor fitted with a mechanical stirrer and a condenser. While purging the headspace with nitrogen and stirring, acrylic acid (14.304 weight %) was added dropwise over 30 min where the temperature was maintained between 130 - 140° C during the addition, allowing the exotherm from the acid base reaction to reach the desired temperature. Next the resulting reaction mixture was heated to 160° C.
• the second step involved adding the acrylic acid / TEPA polymer (31.477 weight %), DI Water (36.825 weight %), and Dowfax 2A1 (0.118 weight %) to a round bottom flask fitted with a mechanical stirrer. Next, a 50% NaOH solution (8.393 weight %) was added to the stirring reaction mixture. Once the mixture was heated and maintained at 40° C, carbon disulfide (14.794 weight %) was added drop-wise over 2 h. One hour within the carbon disulfide addition, another amount of 50% NaOH (8.393 weight %) was charged. The reaction mixture was maintained at 40° C for an additional 2 h. Finally, the reaction was cooled to room temperature and filtered though filter paper to obtain ⁇ 35 weight % polymeric dithiocarbamate product.
• Example 9 a. Acrylamide / Tetraethylenepentamine Polymer Backbone Synthesis
• Tetraethylenepentamine (14.581 weight %) was charged into a glass reactor fitted with a mechanical stirrer and a condenser. While purging the headspace with nitrogen and stirring, a 48.6 % acrylamide solution (30.441 weight %) was added dropwise over lh during which the desired temperature was reached and was maintained between 65 - 75° C. After the acrylamide charge, the temperature was maintained for an additional 1 h. Next, a second charge of TEPA (14.581 weight %) was performed and the resulting reaction mixture was heated to 160° C while collecting the distilled water via a Dean-Stark trap.
• TEPA Tetraethylenepentamine
• the second step involved adding the acrylamide / TEPA polymer (34.004 weight %), DI Water (36.518 weight %), and Dowfax 2A1 (0.122 weight %) to a round bottom flask fitted with a mechanical stirrer. Next, a 50% NaOH solution (7.763 weight %) was added to the stirring reaction mixture. Once the mixture was heated and maintained at 40° C, carbon disulfide (13.830 weight %) was added drop-wise over 2 h. One hour within the carbon disulfide addition, another amount of 50% NaOH (7.763 weight %) was charged. The reaction mixture was maintained at 40° C for an additional 2 h. Finally, the reaction was cooled to room temperature and filtered though filter paper to obtain ⁇ 35 weight % polymeric dithiocarbamate product.
• Example 10 Example 10:
• a sample of scrubber water was treated and then allowed to settle.
• a supernatant sample was taken and measured for total mercury content and then filtered for dissolved mercury content. The objective was to remove mercury.
• the samples were investigated for mercury removal relative to the dosage of Chemistry 2 in wet FGD liquors from two different coal-fired power plants.
• aDTCP is a polydithiocarbamic polymer of the present invention
• bFlocculant is commercially available from Nalco Company and is a very high molecular, 65mole% cationic latex polymer.
• L DTCP is a polydithiocarbamic polymer of the present invention

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