Method for removing corrosive sulfur compounds from a transformer oil

Abstract

A method removes corrosive sulfur compounds from transformer oil. By adding a mixture of rare earths containing aluminum oxide and aluminum silicate to the transformer oil, and enriching the same with an aqueous solution of soluble metal salts, the corrosive sulfur compounds in the transformer oil are neutralized with defined heating and cooling phases. Advantageously, no additional chemical components, such as passivators, are added to the transformer oil. When using a tank for receiving the mixture of the rare earths containing aluminum oxide and aluminum silicate, the reaction can run in the tank. Any aging products that may be present, and the bonded corrosive sulfur compounds are effectively retained within the tank by a filter system, and can be disposed of with the tank.

1 - 15 . (canceled) 
     
     
         16 . A method for removing corrosive sulfur compounds from transformer oil, which comprises the steps of:
 adding a mixture of rare earths containing aluminum oxide/aluminum silicate to the transformer oil;   heating the transformer oil enriched with the rare earth mixture containing the aluminum oxide/aluminum silicate to up to 300 degrees Celsius;   cooling the transformer oil enriched with the rare earth mixture containing the aluminum oxide/aluminum silicate;   enriching the transformer oil with an aqueous solution of soluble metal salts; and   heating the transformer oil to up to 200 degrees Celsius for at least two hours and subsequent cooling to room temperature.   
     
     
         17 . The method according to  claim 16 , which further comprises setting a ratio between a fraction containing the aluminum oxide and a fraction of the aluminum silicate in the rare earth mixture containing the aluminum oxide/aluminum silicate to be in a range of 20:80 to 80:20. 
     
     
         18 . The method according to  claim 16 , which further comprises setting a bulk density of the mixture of rare earths containing the aluminum oxide/aluminum silicate to be 50 to 800 g/l. 
     
     
         19 . The method according to  claim 16 , wherein the aqueous solution has a solution fraction of up to 40% of the soluble metal salts. 
     
     
         20 . The method according to  claim 16 , which further comprises setting a pH value of the mixture of rare earths containing the aluminum oxide/aluminum silicate to be 6.5 to 9.0. 
     
     
         21 . The method according to  claim 16 , which further comprises setting a ratio of the mixture of rare earths containing the aluminum oxide/aluminum silicate to the transformer oil, relative to their respective weights, to be in a range of 0.01:100 to 40:100. 
     
     
         22 . The method according to  claim 16 , which further comprises using rare earth metals of group 3 of the periodic table of elements and lanthanoids. 
     
     
         23 . The method according to  claim 16 , which further comprises admixing at least one of silver, copper, zinc or iron with the mixture of rare earths containing the aluminum oxide/aluminum silicate. 
     
     
         24 . The method according to  claim 16 , which further comprises admixing at least one of silver nitrate to form silver oxides, copper salts to form copper oxides, zinc oxides or iron oxides with the mixture of rare earths containing the aluminum oxide/aluminum silicate. 
     
     
         25 . The method according to  claim 16 , which further comprises disposing the mixture of rare earths containing the aluminum oxide/aluminum silicate in a container, and the container is connected with a transformer housing and the transformer oil is passed into the container and purified, and sulfides bound in the mixture of rare earths containing the aluminum oxide/aluminum silicate remain in the container. 
     
     
         26 . The method according to  claim 25 , which further comprises in an event of a complete consumption of the mixture of rare earths containing the aluminum oxide/aluminum silicate, removing the container from the transformer housing. 
     
     
         27 . The method according to  claim 25 , wherein the container contains an indication of the reactive mixture of rare earths containing the aluminum oxide/aluminum silicate which is still present. 
     
     
         28 . The method according to  claim 25 , wherein the container has a heating unit for heating the transformer oil enriched with the mixture of rare earths containing the aluminum oxide/aluminum silicate. 
     
     
         29 . The method according to  claim 25 , wherein a filter system within the container contains the mixture of rare earths containing the aluminum oxide/aluminum silicate and the transformer oil is introduced into the filter system. 
     
     
         30 . The method according to  claim 25 , which further comprises connecting the container with a purifying device, the purifying device being connected with the transformer housing and the transformer oil may be transferred out of the transformer housing for purification in the purifying device and thus the corrosive sulfur compounds are removed in the container outside the transformer housing. 
     
     
         31 . The method according to  claim 16 , which further comprises setting a ratio between a fraction containing the aluminum oxide and a fraction of the aluminum silicate in the mixture of rare earths containing the aluminum oxide/aluminum silicate to be 50:50. 
     
     
         32 . The method according to  claim 16 , which further comprises setting a ratio of the mixture of rare earth containing the aluminum oxide/aluminum silicate to transformer oil, relative to their respective weights, to be 10:100.