Abstract: An electrodialysis desalination process for seawater comprising the steps of collecting seawater and heating same by solar heat; subjecting seawater thus heated to electrodialysis; and separating same into two portions of a diluted solution and a concentrated brine, is provided, as well as the same system comprising a preheater utilizing solar heat for preheating seawater, an electrodialyser for separating seawater thus preheated by said preheater into said two portions, and means for supplying seawater to the preheater and then from the preheater to the electrodialyser. Various modifications of the above process and system are disclosed. According to the present inventions, electric power consumption in the electrodialysis is saved and solar heat is utilized effectively.

Abstract: An electrodialysis desalination process for seawater comprising the steps of collecting seawater and heating same by solar heat; subjecting seawater thus heated to electrodialysis; and separating same into two portions of a diluted solution and a concentrated brine, is provided, as well as the same system comprising a preheater utilizing solar heat for preheating seawater, an electrodialyser for separating seawater thus preheated by said preheater into said two portions, and means for supplying seawater to the preheater and then from the preheater to the electrodialyser. Various modifications of the above process and system are disclosed. According to the present inventions, electric power consumption in the electrodialysis is saved and solar heat is utilized effectively.

Abstract: An overall process of cooling, dust removal, tar removal and heat recovery of high temperature gas generated in coal gasification furnaces, and apparatuses employed therefor are provided. In this process, specific apparatuses such as fluidized bed-cooler, fluidized bed-combustion furnace for regenerating granules, granular bed filter, gas cooler and, tar scrubber are successively and effectively employed. During the process, high, medium and low pressure steam, for example, are recovered by heat exchange in these apparatuses.

Abstract: An overall process of cooling, dust removal, tar removal and heat recovery of high temperature gas generated in coal gasification furnaces, and apparatuses employed therefor are provided. In this process, specific apparatuses such as fluidized bed-cooler, fluidized bed-combustion furnace for regenerating granules, granular bed filter, gas cooler, and tar scrubber are successively and effectively employed. During the process, high, medium and low pressure steam, for example, are recovered by heat exchange in these apparatuses.

Abstract: A combustion process for reducing nitrogen oxides in combustors is proposed wherein combustion takes place successively forming an incomplete combustion zone, a reducing combustion zone, and a complete combustion zone, respectively corresponding to primary burners, secondary burners and air ports or after-burners, successively arranged in the direction of gas stream in a furnace. According to the present invention, it is possible to reduce nitrogen oxides by improving a manner of combustion without providing any denitrating apparatuses for exhaust gas.

Abstract: A catalytic structure for treating exhaust gases is provided which is obtained by spraying molten aluminum onto the surface of a substrate such as wire netting, expanded metal, etc. in the presence of oxygen, to form on said surface of a substrate a roughened surface through deposit of fine aluminum particles thereon and also an aluminum oxide layer on said roughened surface, and adhering onto this layer a catalytic substance such as a catalyst for reducing nitrogen oxides.The catalytic structure has a high catalyst-retainability to prevent the catalyst from readily peeling off from the surface even when a mechanical impact is applied thereto. Further it exhibits a superior corrosion resistance even in a corrosive environment containing sulfuric acid; hence it is suitably employed for the apparatuses for treating exhaust gases containing nitrogen oxides and sulfur oxides.

Abstract: An improved process for desulfurizing combustion exhaust gases of mainly coal containing sulfur oxides, HF and dust containing Al is provided, which process consists of four steps; a first step of contacting the gases with calcium carbonate or hydroxide in the form of slurry to convert the sulfur oxides into CaSO.sub.3 ; a second step of contacting O.sub.2 with the resulting slurry to convert CaSO.sub.3 into CaSO.sub.4 ; a third step of separating CaSO.sub.4 and mother liquor from the resulting slurry; and a fourth step of preparing a slurry of calcium carbonate or hydroxide to be employed in the first step, from the mother liquor, the pHs of the slurry and the mother liquor in the first and fourth steps being adjusted to 5 or higher by adding alkali such as sodium carbonate.According to the present process, it is possible to prevent hindrance of HF and Al contained in dust to the reaction of SO.sub.2 -absorbent (CaCO.sub.3 or Ca[OH].sub.2) with SO.sub.