Method and apparatus for producing a fertilizer from gas containing sulfur oxides

Abstract

The present invention relates to a method and an apparatus for producing a fertilizer by injecting ammonia into and applying electron beam to gas containing sulfur oxides. Gas containing sulfur oxides is cooled by a heat exchanger ( 2 ) and a cooling tower ( 3 ), and thereafter introduced into a process vessel ( 4 ) in which ammonia is injected into the gas and the gas is irradiated with electron beam. The product of the ratio of the concentration of ammonia to the concentration of water in the gas prior to irradiation of the electron beam and the ratio of the concentration of ammonia to the concentration of water in the gas after irradiation of the electron beam is controlled to be of a predetermined value.

1 . A method of producing a fertilizer from gas containing sulfur oxides by injecting ammonia into and applying electron beam to the gas and collecting a product, characterized in that the product {r A =([NH 3 ]in/[H 2 O]in)×([NH 3 ]out/[H 2 O]out)} of the ratio [NH 3 ]in/[H 2 O]in of the concentration of ammonia to the concentration of water in the gas prior to irradiation of the electron beam and the ratio [NH 3 ]out/[H 2 O]out of the concentration of ammonia to the concentration of water in the gas after irradiation of the electron beam is controlled to be equal to or less than 1.5×10 −5 .  
     
     
         2 . A method of producing a fertilizer from gas containing sulfur oxides according to  claim 1 , characterized in that the ratio {r B =[NH 3 ]out/(2[SO x ]in+[NO x ]in)} of the concentration of ammonia in the gas after irradiation of the electron beam to the sum of a value which is twice the concentration of sulfur oxides and the concentration of nitrogen oxides in the gas prior to irradiation of the electron beam is controlled to be equal to or greater than 1×10 −4 .  
     
     
         3 . A method of producing a fertilizer from gas containing sulfur oxides according to  claim 1  or  2 , characterized in that the value of the ratio r A  is controlled by adjusting a selected one of the concentration of water in the gas, the amount of injected ammonia, the dose of the electron beam, and the temperature of the gas when the gas is irradiated with the electron beam.  
     
     
         4 . A method of producing a fertilizer from gas containing sulfur oxides according to  claim 3 , characterized in that the concentration of water in the gas is adjusted by injecting water into the gas.  
     
     
         5 . A method of producing a fertilizer from gas containing sulfur oxides according to  claim 4 , characterized in that water is injected into the gas before the gas is irradiated with the electron beam.  
     
     
         6 . A method of producing a fertilizer from gas containing sulfur oxides according to  claim 2 , characterized in that the value of said ratio r B  is controlled by adjusting the amount of injected ammonia.  
     
     
         7 . An apparatus for producing a fertilizer from gas containing sulfur oxides, having a process vessel for introducing the gas therein and a collector for collecting a product, said process vessel having an ammonia injecting device and an electron beam irradiation means, characterized by means for controlling the product {r A =([NH 3 ]in/[H 2 O]in)×([NH 3 ]out/[H 2 O]out)} of the ratio [NH 3 ]in/[H 2 O]in of the concentration of ammonia to the concentration of water in the gas prior to irradiation of the electron beam and the ratio [NH 3 ]out/[H 2 O]out of the concentration of ammonia to the concentration of water in the gas after irradiation of the electron beam, to be equal to or less than 1.5×10 5 .  
     
     
         8 . An apparatus for producing a fertilizer from gas containing sulfur oxides according to  claim 7 , characterized by means for controlling the ratio {r B =[NH 3 ]out/(2[SO x ]in +[NO x ]in)} of the concentration of ammonia in the gas after irradiation of the electron beam to the sum of a value which is twice the concentration of sulfur oxides and the concentration of nitrogen oxides in the gas prior to irradiation of the electron beam, to be equal to or greater than 1×10 −4 .  
     
     
         9 . An apparatus for producing a fertilizer from gas containing sulfur oxides according to  claim 7  or  8 , characterized in that said means for controlling the value of the ratio r A  adjusts a selected one of the concentration of water in the gas, the amount of injected ammonia, the dose of the electron beam, and the temperature of the gas when the gas is irradiated with the electron beam.  
     
     
         10 . An apparatus for producing a fertilizer from gas containing sulfur oxides according to  claim 9 , characterized in that the concentration of water in the gas is adjusted by at least one of a gas cooling apparatus for bringing the gas and water into direct contact with each other upstream of the process vessel to vaporize water in the gas for thereby cooling the gas with the heat of vaporization of water, and a water spraying apparatus positioned at the inlet of the process vessel.  
     
     
         11 . An apparatus for producing a fertilizer from gas containing sulfur oxides according to  claim 9 , characterized in that the temperature of the gas is adjusted by at least one of a gas cooling apparatus for bringing the gas and water into direct contact with each other upstream of the process vessel to vaporize water in the gas for thereby cooling the gas with the heat of vaporization of water, and a water spraying apparatus positioned at the inlet of the process vessel.  
     
     
         12 . An apparatus for producing a fertilizer from gas containing sulfur oxides according to  claim 8 , characterized in that said means for controlling the value of the ratio r B  adjusts the amount of injected ammonia.  
     
     
         13 . An apparatus for producing a fertilizer from gas containing sulfur oxides according to  claim 9  or  12 , characterized in that a plurality of ammonia injection control devices are provided, and at least one of the ammonia injection control devices is capable of injecting a trace amount of ammonia to adjust said amount of injected ammonia.