An apparatus and process are provided for electricity production and high-efficiency trapping of carbon dioxide, using carbon dioxide within combustion exhaust gas and converging technologies associated with a carbon dioxide absorption tower and a generating device using ions which uses a difference in concentration of salinity between seawater and freshwater. It is expected that enhanced electrical energy production efficiency, an effect of reducing costs for the operation of a carbon dioxide trapping process, and electricity production from carbon dioxide, which is a greenhouse gas, can be simultaneously achieved by increasing the difference in concentration using an absorbent for absorbing carbon dioxide.

A system and method for purifying engine exhaust by using ozone; the system for purifying engine exhaust by using ozone comprises a reaction field (202), which is used to mix an ozone stream and an exhaust stream for reaction; the system has an excellent purification effect without needing to add a large amount of urea.

The invention relates to a method and to an apparatus for separating and utilizing carbon dioxide. According to the invention, carbon dioxide (3a, 3b) is separated from air (1a) being conducted to a building and/or from air (1c,1d) being circulated in the building to reduce the level of carbon dioxide in indoor air (1b) of the building (4), the carbon dioxide (3a, 3b) is recovered, and the carbon dioxide is conducted to a carbon dioxide treatment stage (5), where a chemical compound (6) is formed from the carbon dioxide. In addition, the invention relates to the use of the method.

The invention relates to a method and to an apparatus for separating and utilizing carbon dioxide. According to the invention, carbon dioxide (3a, 3b) is separated from air (1a) being conducted to a building and/or from air (1c,1d) being circulated in the building to reduce the level of carbon dioxide in indoor air (1b) of the building (4), the carbon dioxide (3a, 3b) is recovered, and the carbon dioxide is conducted to a carbon dioxide treatment stage (5), where a chemical compound (6) is formed from the carbon dioxide. In addition, the invention relates to the use of the method.

The present invention provides an integrated process for carbon dioxide capture, sequestration and utilisation, which comprises: a) providing an aqueous slurry comprising an aqueous liquid and a particulate solid comprising an activated magnesium silicate mineral; b) in a dissolution stage, contacting a CO.sub.2-containing gas stream with the aqueous slurry at a first pressure to dissolve magnesium from the mineral to provide a slurry comprising a magnesium ion enriched carbonated aqueous liquid and a magnesium depleted solid residue; and c) in a precipitation stage, precipitating magnesium carbonate from magnesium ions dissolved in step b) by multiple successive stage-wise reductions in pressure, with each stage being at a lower pressure than the preceding stage;
wherein each successive stage-wise reduction in pressure releases CO.sub.2 which is correspondingly stage-wise compressed and recycled back into the dissolution stage.

The present invention provides an integrated process for carbon dioxide capture, sequestration and utilisation, which comprises: a) providing an aqueous slurry comprising an aqueous liquid and a particulate solid comprising an activated magnesium silicate mineral; b) in a dissolution stage, contacting a CO.sub.2-containing gas stream with the aqueous slurry at a first pressure to dissolve magnesium from the mineral to provide a slurry comprising a magnesium ion enriched carbonated aqueous liquid and a magnesium depleted solid residue; and c) in a precipitation stage, precipitating magnesium carbonate from magnesium ions dissolved in step b) by multiple successive stage-wise reductions in pressure, with each stage being at a lower pressure than the preceding stage;
wherein each successive stage-wise reduction in pressure releases CO.sub.2 which is correspondingly stage-wise compressed and recycled back into the dissolution stage.

The disclosure provides seven integrated methods for the chemical sequestration of carbon dioxide (CO.sub.2), nitric oxide (NO), nitrogen dioxide (NO.sub.2) (collectively NO.sub.x, where x=1, 2) and sulfur dioxide (SO.sub.2) using closed loop technology. The methods recycle process reagents and mass balance consumable reagents that can be made using electrochemical separation of sodium chloride (NaCl) or potassium chloride (KCl). The technology applies to marine and terrestrial exhaust gas sources for CO.sub.2, NOx and SO.sub.2. The integrated technology combines compatible and green processes that capture and/or convert CO.sub.2, NOx and SO.sub.2 into compounds that enhance the environment, many with commercial value.

A urea production process which includes and a synthesis section, a recovery section and evaporation section and a finishing section wherein the evaporation section includes a first evaporator and downstream thereof a second evaporator for urea solution. The second evaporator operates a lower pressure than the first evaporator to provide a urea melt and second vapor, solidifying the urea melt in a finishing section to provide a solid urea produce and off gas, scrubbing the off gas followed by condensing to produce a first condensate and second condensate; supplying the first condensate to a wastewater treatment section and supply the second condensate to the scrubber wherein the second condensate is used as a scrub liquid in the scrubber.

A system for resource recycling of sulfur dioxide includes a charcoal reduction furnace, a high temperature dust remover, a cooling separator A, a liquid sulfur tank, a cooling separator, a tail gas absorption tower, a gas stripping tower, a hypo reactor, a centrifuge, a mother liquor tank and a thickener. And a method for resource recycling of sulfur dioxide includes the following steps: (1) preparing elemental sulfur, (2) removing dust from a process gas containing gaseous sulfur, (3) separating elemental sulfur, (4) reabsorbing residual SO.sub.2 gas, (5) purifying sulfur powder, (6) preparing a slurry of cured hypo, (7) performing liquid-solid separation, and (8) preparing an absorption slurry. According to the method, SO.sub.2 gas is reduced into liquid sulfur and sulfur powder, and sodium thiosulfate is coproduced.

A method for reducing carbon dioxide to manufacture a multi-carbon hydrocarbon compound includes steps as follows. A reduction reaction with separation and purification system is provided, which includes a carbon dioxide absorption tower, a reactor, a gas-liquid separation device, a liquid-phase purification device and a gas-phase purification device. An absorption step is performed, wherein a carbon dioxide gas is absorbed to form a mixed solution. A photocatalysis step is performed, wherein the mixed solution is reacted with a photocatalyst to form a carbon-based compound. A separation step is performed, wherein the carbon-based compound is separated to form a liquid-phase mixture and a gas-phase mixture. A liquid-phase purification step is performed, wherein the liquid-phase mixture is purified. A gas-phase purification step is performed, wherein the gas-phase mixture is separated and purified to form a multi-carbon hydrocarbon compound.