An exhaust gas purifying and heat recovering system and method for sludge treatment. The system comprises: a first heat exchange flow path including first, second, and third heat exchangers, a first heat exchange medium that is circulated in the first heat exchange flow path to heat process gas for sludge treatment in the first heat exchanger, a second purification and heat exchange flow path including a heat exchange tank containing a second liquid heat exchange medium and which receives the exhaust gas after sludge treatment, and a third dirty liquid separation flow path including a dirty liquid separation tank provided between a dirty liquid outlet of the heat exchange tank and a clean liquid inlet of the heat exchange tank for separating the dirty liquid after purging the exhaust gas, the separated liquid being again directed to the clean liquid inlet of the heat exchange tank.

Process for reducing the content of NOx and N2O from an input tail gas (10) of a nitric acid process, said input tail gas having a temperature lower than 400 C., the process comprising an abatement stage at least including a deN2O stage and deNOx stage and providing a conditioned tail gas (12) having a temperature greater than the input tail gas (10), wherein, prior to submission to said abatement stage, said input tail gas (10) is pre-heated to a temperature of at least 400 C. by indirect heat exchange with at least a portion of said conditioned gas (12).

Methods of sequestering carbon dioxide (CO.sub.2) are provided. Aspects of the methods include contacting an aqueous capture ammonia with a gaseous source of CO.sub.2 under conditions sufficient to produce an aqueous ammonium carbonate. The aqueous ammonium carbonate is then combined with a cation source under conditions sufficient to produce a solid CO.sub.2 sequestering carbonate and an aqueous ammonium salt. The aqueous capture ammonia is then regenerated from the from the aqueous ammonium salt. Also provided are systems configured for carrying out the methods.

Oxygen is removed from a gas feed such as a landfill gas, a digester gas or an industrial CO.sub.2 off-gas by heating the feed gas, optionally removing siloxanes and silanols from the heated feed gas, optionally removing part of the sulfur-containing compounds in the heated feed gas, injecting one or more reactants for oxygen conversion into the heated feed gas, carrying out a selective catalytic conversion of any or all of the volatile organic compounds (VOCs) present in the gas, including sulfur-containing compounds, chlorine-containing compounds and any of the reactants injected, in at least one suitable reactor, and cleaning the resulting oxygen-depleted gas. The reactants to be injected comprise one or more of H.sub.2, CO, ammonia, urea, methanol, ethanol and dimethyl ether (DME).

A plant according to an embodiment includes a gas turbine; a heat recovery unit that includes a primary heat recovery steam generator in which a primary heat exchanging unit generates primary steam by exchanging heat that is the thermal energy of the flue gas from the gas turbine, and a secondary heat recovery steam generator that is installed independently from the primary heat exchanging unit, and in which a secondary heat exchanging unit generates secondary steam by exchanging heat that is the thermal energy of the flue gas partly having exchanged heat in the primary heat exchanging unit included in the primary heat recovery steam generator; a primary steam turbine; a CO.sub.2 recovery unit; and a first reboiler heat supply line.

An all-condition auxiliary denitration system and an operation method thereof are provided. The system includes a heat-storage medium heater, a low-temperature reheater, an economizer, and an SCR denitration device which are successively interconnected, and further including a heat-storage medium tank and a heat-storage medium and feedwater heat exchanger. A flow of a cold heat-storage medium entering the heat-storage medium heater is regulated, so that heat absorption of the heat-storage medium is matched with a boiler load. Flows of hot heat-storage medium and feedwater, which enter the heat-storage medium and feedwater heat exchanger, are regulated through a feedwater regulating valve and a hot heat-storage medium outlet regulating valve. A total feedwater flow is regulated with assistance of a bypass feedwater regulating valve, so that a temperature of flue gas entering the SCR denitration device is kept in an optimal operation range under different boiler loads, and denitration efficiency is ensured.

A system and method for heat produced at a nuclear power plant as the energy source for carbon dioxide sequestration while simultaneously producing electricity. The system includes a nuclear power plant that differs significantly from conventional designs inasmuch as its design is tightly integrated into the carbon dioxide sequestration system. The system generates electricity and sequesters carbon dioxide at the same time. Instead of simply generating electricity from the nuclear reactor and then using that electricity to run a sequestration process, the method is designed to directly provide the requisite thermal energy to the sequestration process, and simultaneously power an electrical generator. Another feature of the system design is a method of optimizing load balancing between the electrical grid and carbon dioxide sequestration.

A method of operating and an arrangement for a steam boiler system including a furnace and along a following flue gas channel a number of superheaters, a number of economizers, and at least one air preheater located in the flue gas channel downstream of the economizers, a fabric filter baghouse located in the flue gas channel downstream of the air preheater, and downstream of the fabric filter baghouse is located a selective catalytic reduction (SCR) system including an SCR reactor, a high pressure steam coil heater upstream of the SCR reactor and a gas-gas heat exchanger connected upstream and downstream of the SCR reactor to transfer heat from flue gas after the SCR reactor to the flue gas upstream of the high pressure steam coil heater.

An energy-efficient, space-saving, low-cost, waste-heat-utilizing ventilating air conditioning apparatus uses a honeycomb rotor having a function of adsorbing or absorbing contaminants such as carbon dioxide and VOC gas. The honeycomb rotor is disposed in a rotor rotating device having at least a processing zone and a re-generation desorption zone. Air to be processed is passed through the processing zone to remove contaminants such as carbon dioxide to produce supply air. Water is directly sprayed or dropped into a heat exchanger provided at an entrance of the re-generation desorption zone to evaporate the generated water film by heating. The generated saturated steam is introduced for desorbing carbon dioxide and pollutants, and the stream is discharged the stream outdoors. The ventilating air conditioning apparatus can operate without the energy loss associated with ventilation.

An all-condition auxiliary denitration system and an operation method. thereof are provided. The system includes a heat-storage medium heater, a low-temperature reheater, an economizer, and an SCR denitration device which are successively interconnected, and further including a heat-storage medium tank and a heat-storage medium and feedwater heat exchanger. A flow of a cold heat-storage medium entering the heat-storage medium heater is regulated, so that heat absorption of the heat-storage medium is matched with a boiler load. Flows of hot heat-storage medium and feedwater, which enter the heat-storage medium and feedwater heat exchanger, are regulated through a feedwater regulating valve and a hot heat-storage medium outlet regulating valve. A total feedwater flow is regulated with assistance of a bypass feedwater regulating valve, so that a temperature of flue gas entering the SCR denitration device is kept in an optimal operation range under different boiler loads, and denitration efficiency is ensured.