System and method for cleaning fracking sand

Abstract

According to at least one exemplary embodiment, a system for cleaning fracking waste slurry containing water, sand, and organic matter may include a slurry sump, separator, dewatering screen, water tank, surge hopper, and a sand cleaner. The sand cleaner may further include a rotary retort furnace which may both dry the sand and oxidize any organic matter. The cleaning system may recycle the water used by returning it to the truck that brought the waste slurry. Further, the dried and cleaned sand produced by the system may be suitable for re-use or non-hazardous disposal.

What is claimed is: 
     
         1 . A system for cleaning a sand slurry, the sand slurry comprising at least sand and a liquid, comprising:
 a separator;   a dewatering screen; and   a sand cleaner;   wherein the separator is configured to separate the sand slurry into a first portion and a second portion, the first portion comprising excess liquid substantially free of particulate matter, and the second portion comprising partially concentrated slurry,   wherein the dewatering screen is configured to remove the liquid from said second portion until it contains at least about 85% solid matter and less than about 2% combustible organic matter, and   wherein the sand cleaner includes a furnace, said furnace configured to heat said second portion to a temperature sufficient to remove substantially all liquid and oxidize substantially all organic matter contained in said second portion.   
     
     
         2 . The system of  claim 1 , further comprising a slurry sump. 
     
     
         3 . The system of  claim 2 , further comprising a slurry pump, the slurry pump configured to pump sand slurry out of the slurry sump. 
     
     
         4 . The system of  claim 3 , further comprising a water tank. 
     
     
         5 . The system of  claim 4 , wherein the slurry sump, water tank, and separator are in fluid communication with each other,
 wherein the slurry sump may be configured to receive the sand slurry from an outside source and the separator may be configured to receive the sand slurry from the slurry sump, and   wherein both the water tank and the slurry sump are configured to receive the first portion from the separator.   
     
     
         6 . The system of  claim 1 , further comprising a surge hopper. 
     
     
         7 . The system of  claim 1 , wherein the separator is a hydrocyclone. 
     
     
         8 . The system of  claim 1 , wherein the furnace is configured to heat said second portion to a temperature between about 1,200° F. and about 1,500° F. 
     
     
         9 . The system of  claim 1 , wherein the system is configured to receive the sand slurry from a truck tank. 
     
     
         10 . The system of  claim 1 , wherein the system is configured to pump the first portion to a truck tank. 
     
     
         11 . The system of  claim 1 , wherein the furnace is a rotary retort furnace. 
     
     
         12 . The system of  claim 1 , wherein the furnace is configured to control the oxygen content of the gases inside the furnace. 
     
     
         13 . The system of  claim 12 , wherein the furnace is configured to maintain the oxygen content of the gases inside the furnace between about 5% and about 10%. 
     
     
         14 . A method for cleaning a sand slurry and producing cleaned sand, the sand slurry comprising at least sand and a liquid, comprising:
 receiving the sand slurry from an outside source;   separating the sand slurry in a separator into a first portion and a second portion, wherein the first portion comprising excess liquid substantially free of particulate matter, and the second portion comprising partially concentrated slurry;   removing the liquid from said second portion until it becomes a cake, said cake containing at least about 85% solid matter and less than about 2% combustible organic matter; and   heating the cake in a furnace to a temperature sufficient to remove substantially all liquid and oxidize substantially all organic matter contained in said cake.   
     
     
         15 . The method of  claim 14 , wherein the cake is heated to a temperature between about 1,200° F. and about 1,500° F. 
     
     
         16 . The method of  claim 14 , further comprising controlling the oxygen content of the gases inside the furnace. 
     
     
         17 . The method of  claim 16 , wherein the oxygen content of the gases inside the furnace is maintained between about 5% and about 10%. 
     
     
         18 . The method of  claim 14 , further comprising controlling the rate of flow of the cake into the furnace. 
     
     
         19 . The method of  claim 14 , further comprising pumping the first portion to a holding container. 
     
     
         20 . The method of  claim 19 , wherein the holding container is one of a water tank, a slurry sump, or a truck.