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  Flue gas purification process using a sorbent polymer composite materialUSPTO Application #: 20070207923Title: Flue gas purification process using a sorbent polymer composite material Abstract: This invention provides a process of removing sulfur oxides, mercury vapor, and fine particulate matters from industrial flue gases that contain such pollutants. The pollutants are removed by modules, which contain microporous adsorbent (i.e., sorbent) material that is held within a polymer matrix. The preferred polymers are fluoropolymers. The composite material that contains the microporous absorbent material held within a polymer matrix removes sulfur oxides by converting them into high concentration sulfuric acids. It also removes mercury vapor by chemically adsorbing the mercury into the matrix. It also removes fine particulate matters by surface filtration. The sulfuric acid that is produced inside the composite material is automatically expelled onto the external surfaces of the composite material and is drained into an acid reservoir together with the fine particulate matters which are washed from the external surfaces of the composite material by the constant dripping of the sulfuric acid along the external surfaces of the composite material. (end of abstract) Agent: Gore Enterprise Holdings, Inc. - Newark, DE, US Inventors: Xia-Chun Lu, Xiaoqun Wu USPTO Applicaton #: 20070207923 - Class: 502401000 (USPTO) Related Patent Categories: Catalyst, Solid Sorbent, Or Support Therefor: Product Or Process Of Making, Solid Sorbent, Organic The Patent Description & Claims data below is from USPTO Patent Application 20070207923. Brief Patent Description - Full Patent Description - Patent Application Claims
CROSS-REFERENCE TO RELATED APPLICATIONS [0001] This application is a divisional of U.S. application Ser. No. 10/872,288 filed on Jun. 19, 2004, which claims the benefit of U.S. provisional application 60/478,881 filed on Jun. 20, 2003, now abandoned. REFERENCE TO A COMPACT DISK APPENDIX [0003] Not applicable. BACKGROUND OF THE INVENTION [0004] 1. Field of the Invention [0005] The present invention relates to a pollution control method for removing sulfur oxides, mercury vapor, and fine particulate matters from industrial flue gases, such as coal-fired power plant flue gas. [0006] 2. Description of the Related Art [0007] Coal-fired power generation plants, municipal waste incinerators, and oil refinery plants generate huge amounts of flue gases that contain substantial varieties and quantities of environmental pollutants, such as sulfur oxides (SO.sub.2, and SO.sub.3), nitrogen oxides (NO, NO.sub.2), mercury (Hg) vapor, and particulate matters (PM). In the United States, burning coal alone generates about 27 million tons of SO.sub.2 and 45 tons of Hg each year. [0008] The destructive effects of various coal-burning pollutants on human health and on the ecosystem were recognized a long time ago. For example, SOx and NOx have been linked to the outbreak of respiratory diseases in the affected areas. They also form acid rains, which damage forests, fisheries, and architectures. As for Hg, it is a potent toxin to the nervous system. Exposure to mercury can affect the brain, spinal cord, and other vital organs. It is particularly dangerous to developing fetuses and young children. Relatively less attention is paid to the particulate matters (PM). However, fine particulates, especially those of less than 2.5-micrometer size (PM2.5), cause great health problems on human beings. PM2.5 is typically loaded with various toxic chemicals such as sulfates, nitrates, and heavy metals. PM2.5 is found to trigger heart attacks, damage lungs and kill thousands of people every year. [0009] The typical methods of removing pollutants from industrial flue gases are designed to remove individual pollutants. For example, the prevailing technology for flue gas desulfurization (FGD), or SO.sub.2 removal, is the limestone based wet scrubber or dry scrubber, which uses alkali limestone to neutralize and remove SOx. The prevailing technology for flue gas NOx removal is the selective catalytic reduction (SCR), which uses ammonia or urea to catalytically convert NOx into nitrogen, oxygen, and water. These technologies are typically very complicated and expensive. [0010] In U.S. Pat. No. 6,132,692, a process for reducing multiple pollutants (particles, Hg, NOx, and SO.sub.2) is disclosed. In this process, an electrical barrier discharge reactor produces the HgO and acids HNO.sub.3 and H.sub.2SO.sub.4, a wet electrostatic precipitator (ESP) collects the HgO, acids, and particulates. The collected pollutants are then drained from the wet ESP for further processing. However, the SO.sub.2 and NOx removal efficiencies of this process are limited, while the system is expensive, energy input is very high, and the collected acid solution may need treatment as liquid waste. [0011] Activated carbon based flue gas purification technology is frequently studied and has enjoyed some commercial success. The technology can potentially remove both SOx and mercury vapor simultaneously. In U.S. Pat. No. 3,486,852, an adsorbing process and apparatus for the removal of SO.sub.2 from industrial waste gases is disclosed. The adsorbing units consist of an adsorbing zone, two regenerating (or washing) zones and a drying zone. The washing liquid (water) from the washing zone can be neutralized with an alkaline compound in a neutralization tank or passed to an acid concentrator. In U.S. Pat. No. 4,164,555, a pollution control system, along with the method in which SO.sub.2 in flue gases are adsorbed by activated char in a gas-solid contacting device, is disclosed. The saturated char is regenerated in an integrated desorption-reduction vessel; to which crushed coal and combustion-supporting air are supplied. The regeneration process generates SO.sub.2 and CO.sub.2 and consumes a portion of the char. The generated SO.sub.2 can be fed into a sulfuric acid manufacturing plant. [0012] All the activated carbon based flue gas purification technologies require a carbon regeneration process, because the activated carbon will be saturated by the adsorbed SO.sub.2 or the converted SO.sub.3 and/or H.sub.2SO.sub.4. The regeneration process requires either high temperature degassing or water washing. The disadvantages of a regenerating process are: 1) it consumes activated carbon; 2) it generates secondary pollution, such as low concentration acid solution; and 3) it makes the overall system complicated and expensive. [0013] Therefore, there is a need to provide a simple system that can simultaneously remove multiple flue gas pollutants such as SOx, Hg vapor, and PM2.5 with low cost. It is desirable that the system is simple, does not generate secondary pollutions, and has the capability of producing a useful end product. More specifically, an activated carbon based system without a costly and complicated regeneration process is desirable. BRIEF SUMMARY OF THE INVENTION [0014] In accordance with the present invention, there is provided a process for removing multiple pollutants from industrial flue gases such as the flue gas from a coal-fired power generating plant. The flue gas is conveyed through a series of heat exchangers in the exhaust duct including direct water spray to cool the flue gas from an elevated temperature to less than 100.degree. C. The cooled flue gas is then introduced into a sorbent-polymer-composite (SPC) sorbent house, where the pollutants such SOx, Hg vapor, and PM2.5 are removed. Thereafter, the flue gas is discharged into the stack substantially free of the pollutants. [0015] Further in accordance with the present invention, there is provided an SPC sorbent house that removes SO.sub.2 and SO.sub.3 from flue gas without requiring a complicated regeneration process. The SOx from the flue gas are converted on the SPC material to H.sub.2SO.sub.4 and the converted H.sub.2SO.sub.4 is automatically expelled onto the SPC external surfaces, where the acid solution drips down to the acid reservoir and is collected as a product. The collected solution contains a high H.sub.2SO.sub.4 concentration (10-60%) and can be used or sold as industrial material with minimal processing. [0016] In another aspect of the present invention, there is provided an SPC sorbent house that removes Hg vapor from flue gas by chemically adsorbing Hg vapors (either elemental mercury or oxidized mercury) into its matrix. The adsorbed Hg vapor is chemically fixed on the carbon internal surfaces without being able to leach out. The SPC sorbent house has such a high Hg fixation capacity that the SPC sorbent material can be used for flue gas purification for a long period of time continuously while maintaining a high Hg removal efficiency. With a careful design, the usable life of the SPC sorbent material for coal-fired flue gas Hg removal can be more than 10 years. [0017] Additionally, in accordance with the present invention, there is provided an SPC sorbent house that removes fine particulate matters (PM2.5) from flue gas by surface filtration on the SPC external surfaces with or without one or more externally laminated porous PTFE (polytetrafluoroethylene) membranes. The trapped particles will be removed from the SPC surfaces by the dripping H.sub.2SO.sub.4 solution (i.e., the solution that is generated when the SO.sub.x from the flue gas is converted on the SPC material to H.sub.2SO.sub.4 which is then expelled from the interior of the SPC material to the external surfaces of the SPC material, there forming droplets which join together and drip downwards onto the lower sections of the SPC material). [0018] Accordingly, a principal objective of the present invention is to provide a sorbent-based method and apparatus for removing multiple pollutants, such as SOx, Hg vapor, and PM2.5, from industrial flue gases to a level required by the air quality standards, while reducing the cost of removing the pollutants by eliminating the costly sorbent regeneration process and producing the salable sulfuric acid solution. [0019] Another object of the present invention is to provide a method and apparatus for converting SOx in the industrial flue gases into sulfuric acid and expelling and collecting the sulfuric acid for sales. The sorbent material and the apparatus are so designed that no separate sorbent regeneration is required, neither by high temperature degassing nor water washing, and the collected solution has a high sulfuric acid concentration (10-60% by weight). [0020] Another object of the present invention is to provide a method and apparatus for removing Hg vapor from industrial flue gases by chemically fixing the Hg vapor onto the sorbent matrix. [0021] A further object of the present invention is to provide a method and apparatus for removing PM2.5 from industrial flue gases by surface filtration using the porous PTFE membranes. The trapped particles will be washed away from the membrane surfaces by the dripping sulfuric acid solution; therefore, no separate dust cake removal is required. Continue reading... Full patent description for Flue gas purification process using a sorbent polymer composite material Brief Patent Description - Full Patent Description - Patent Application Claims Click on the above for other options relating to this Flue gas purification process using a sorbent polymer composite material patent application. ###  How KEYWORD MONITOR works... a FREE service from FreshPatents1. Sign up (takes 30 seconds). 2. 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