Babcock-hitachi Kabushiki Kaisha

Wisconsin Alumni Research Foundation

Mitsubishi Hitachi Power Systems, Ltd.

Hitachi Power Systems America, Ltd

Mitsubishi Power, Ltd.

Hirofumi Kikkawa

Takanori Nakamoto

Shigehito Takamoto

Hiroshi Ishizaka

Hiroyuki Kaku

Fumito Nakajima

Toshio Katsube

Masakatsu Nishimura

Shigeru Nozawa

Kazunori Shoji

Hiroyuki Nosaka

Yoshinori Ohtani

Yasuyoshi Kato

Yasuyuki Nishimura

Atsushi Katagawa

Jun Shimamura

Kazuki Kobayashi

Nobuyasu Meguri

Masayasu Murata

Hiroshi Takezaki

Marc A Anderson

Hiroshi Kuroda

Naomi Imada

Song Wu

Naoki Oda

Eiji Miyamoto

Yoshinori Nagai

Isato Morita

Koichi Yokoyama

Takayuki Saitou

Masaharu Kuramoto

Hiroshi Terada

Mitsuharu Kon

Masayuki Yamamoto

Kunikatsu Yoshida

Takashi Muramoto

Udo Zirn

Goki Sasaki

Yoshinori Taguchi

Wakako Shimohira

Miyamoto Eiji,

Miyamoto Eiji

In order to heighten the recovery of activated carbon by separation in a flotation device and stably inhibit mercury from being re-emitted in a desulfurization/absorption tower and from coming into gypsum to be recovered, a method is provided, the method comprising: adding activated carbon to an absorption liquid to be sprayed into the desulfurization/absorption tower to thereby remove mercury components from the flue gas simultaneously with desulfurization of the flue gas; sending the absorption liquid used for the desulfurization to the flotation device to thereby form a foam bubble layer; reducing the drainage volume so that the physical properties of the bubble layer are within given ranges, in such an amount that the concentration of chlorine ions in the absorption liquid does not exceed a given value; and simultaneously adding Ca and/or Mg ions and a frothing agent to the absorption liquid.

Method and device for wet flue-gas desulfurization

A method of recovering carbon dioxide, includes bringing gas to be processed containing carbon dioxide (CO) and oxygen into contact with the CO-absorbing solution in an absorption column to form a CO-rich solution; circulating the solution in a regeneration column to thermally release and recover COand recirculating the absorbing solution as a CO-poor solution inside the absorption column; and performing heat exchange between the solution being delivered from the absorption column to the regeneration column and the solution recirculated from the regeneration column to the absorption column, wherein an alkanolamine aqueous solution containing a silicone oil and/or an organosulfur compound is added to the solution inside the absorption column and/or the solution recirculated from the regeneration column to the absorption column to adjust the composition of the absorbing solution inside the absorption column.

Carbon dioxide-absorbing solution and method of recovering carbon dioxide

After adjusting an exhaust gas temperature at an exit of a heat recovery unit () of an exhaust gas treating apparatus to not more than a dew point temperature of sulfur trioxide (SO), a heavy metal adsorbent is supplied from a heavy metal adsorbent supply unit () disposed in an exhaust gas at an entrance of a precipitator () or an intermediate position within the precipitator (), and the exhaust gas containing the heavy metal adsorbent is supplied into the precipitator (). Preferably at this stage, the heavy metal adsorbent is supplied into the exhaust gas at the entrance of the precipitator () 0.1 seconds after the exhaust gas temperature at the exit of the heat recovery unit () has been adjusted to not more than the dew point temperature of SO. Further preferably, in order to prevent acid corrosion of equipment, the heavy metal adsorbent is supplied after spraying an alkali into the exhaust gas at the entrance or exit of the heat recovery unit () and adjusting the exhaust gas temperature at the exit of the heat recovery unit to not more than the dew point temperature of SO. Accordingly, even when coal with a high sulfur content is used as fuel, heavy metals in the exhaust gas can be removed effectively.

Exhaust gas treating method and apparatus

An apparatus for removing of traces of toxic substances from exhaust gas, comprising, disposed in sequence from the upstream side in a flow channel of exhaust gas emitted from combustion equipment, a denitration unit including a denitration catalyst layer capable of removing nitrogen oxides from the exhaust gas and capable of oxidizing metallic mercury; an air preheater adapted for heat exchange between air for combustion in the combustion equipment and the exhaust gas; a dust removal unit having a bag filter containing a catalyst for metallic mercury oxidation; and a desulfurization unit for removing sulfur oxide from the exhaust gas. The bag filter may be disposed in advance of the desulfurization unit. Thus, there can be provided an apparatus for removing of traces of toxic substances from exhaust gas that is stable over a prolonged period of time and is highly reliable; and provided a method of operating the same.

Apparatus for removing of trace of toxic substance from exhaust gas and method of operating the same

A system is provided that prevents inhibition of adsorption of Hg and other heavy metals by activated carbon or other heavy metal adsorbent due to prior adsorption of sulfur trioxide (SO) in an exhaust gas containing SO. As it has been found that while SOis adsorbed, the adsorption of SOprecedes the adsorption of Hg and other heavy metals onto activated carbon, a basic substance injection system is disposed along an exhaust gas flow channel at an upstream side of an activated carbon injection system, thereby attaining effective removal of Hg and other heavy metals from the exhaust gas by adsorption thereof onto surface pores of the activated carbon. The SOconcentration after removal by basic substance conversion is computed from the SOconcentration before removal, and the activated carbon injection rate can be controlled based on the concentration after removal.

Exhaust gas purifying method and apparatus

A method and apparatus for treating an exhaust gas comprising heavy metals, wherein the apparatus comprises a heat recovery unit, recovering exhaust gas heat at an exit of the air preheater; a precipitator, collecting soot/dust contained in an exhaust gas at an exit of the heat recovery unit; a wet flue gas desulfurizer, removing sulfur oxides contained in the exhaust gas at the exit of the precipitator; and a reheater, heating the exhaust gas at the exit of the wet flue gas desulfurizer. Each of the heat recovery unit and the reheater has a heat exchanger tube, and a circulation line is disposed to connect the heat exchanger tubes. A sulfur trioxide (SO) removing agent is supplied to the upstream side of the heat recovery unit, and the temperature of the exhaust gas at the exit of the heat recovery unit is adjusted to not more than a dew point of sulfur trioxide.

Method and apparatus for treating discharge gas

Methods and apparatus for pollution control which are well suited for use in a coal power plant are described. Ash is collected and injected into the flue gas stream at a location upstream of a cooling module. The ash acts as an absorbent and/or reactant material onto which condensate may condense. By re-introducing ash to keep the condensation forming wet areas within the system, lower cost materials which are less corrosion resistant than needed for wet operating conditions can be used. Mercury recovery and SO3 removal is facilitated by the cooling process and re-introduction of collected ash. Activated carbon and/or an alkali absorbent material may be added. Use of a dry ESP and/or fabric filter as opposed to a wet ESP for particulate collection leads to cost benefits. Energy recovered by the cooling of the flue gas may be re-used to heat turbine condensate leading to improved energy efficiency.

Methods and apparatus for performing flue gas pollution control and/or energy recovery

An exhaust smoke processing system comprises air preheater for heating combustion air by exhaust smoke discharged from a boiler, a heat recoverer for heating a heat medium by exhaust smoke discharged from the air preheater, a dust collector for collecting soot and dust in exhaust smoke discharged from the heat recoverer, a wet-type exhaust smoke processing apparatus for processing exhaust smoke discharged from the dust collector, a reheater for heating exhaust smoke discharged from the wet-type exhaust smoke processing apparatus by the heat medium, and a heat medium circulation pipe passage for circulating the heating medium between the reheater and the heat recoverer. the system measures a heavy metal concentration in the exhaust smoke and adjusts the temperature of exhaust smoke at an outlet of the heat recoverer such that the measured value falls within a predetermined range.

Exhaust smoke-processing system

Disclosed are a method and an apparatus for treating an effluent containing ammonia in which method and apparatus NO concentration in the gas at the outlet of a catalyst tower does not rise to a high level even when the NHconcentration in the effluent was reduced and the amount of hazardous substances formed is small; in the method and apparatus, an NH-containing effluent A and a carrier gas (steam C and combustion gas F) are contacted in stripping towerto transfer the NHfrom the NH-containing effluent to a gas phase, the gas containing the generated NHis heated with pre-heaterand then contacted with catalyst layerplaced in catalyst towerto decompose the NHinto nitrogen and water; and at that time, the oxygen concentration in the gas to be introduced into catalyst towerand the NO concentration in the gas discharged from catalyst towerare determined by measuring instrumentsand, respectively, and the oxygen concentration in the gas to be introduced into catalyst toweris adjusted by adjusting valveso that the NO concentration becomes within a prescribed range.

Method for treating amonia-containing effluent water

A wet-type flue gas desulfurization method and plant making use of a solid desulfurizing agent in which exhaust gas exhausted from a combustion apparatus such as a boiler is brought into contact with absorbing liquid to absorb sulfur oxide from the exhaust gas into the absorbing liquid followed by neutralization of the absorbing liquid containing the sulfur oxide thus absorbed. The solid desulfurizing agent is selectively retained in an absorbing liquid neutralizing zone and the absorbing liquid, containing water as a main constituent and solid products formed from the absorbed sulfur oxide, is selectively removed from the neutralizing zone. In the neutralizing zone the upward flow of the absorbing liquid, optionally augmented by an upward flow of air or water, forms a fluidized bed of limestone particles, thereby preventing coating of the limestone by gypsum and thereby retaining reactivity of limestone. According to the present invention, coexistence of Al and F in the absorbing liquid seldom deteriorates the desulfurizing performance. Further, it is possible to reduce power and cost required to grind limestone and to achieve a higher desulfurizing performance.

Wet-type flue gas desulfurization plant and method making use of a solid

Wet-type flue gas desulfurization plant

A metal oxide particulate membrane is made more electrically conductive, and thus more suitable for electrochemical cells by the incorporation into the membrane of a dopant element. The dopant is dissolved in an alcohol and then incorporated in the sol-gel process used to form the particulate metal oxide membrane. The invention is exemplified by a niobium doped titanium dioxide ceramic membrane which has good porosity while having a conductivity several orders of magnitude higher than a similar membrane made without incorporating the niobium dopant.

Niobium-doped titanium membranes

Growing community of inventors

Hiroshima, Japan

Hirofumi Kikkawa