Ammonia recycling still for a refrigeration system and method therefor

Abstract

An ammonia still apparatus of the invention is used to reclaim ammonia from contaminated ammonia refrigeration fluid in an ammonia refrigeration system. The ammonia still apparatus is used in fluid communication with the ammonia refrigeration system and can be run manually or automatically using an electronic controller, such as a programmable logic controller. The ammonia is separated from the contaminated refrigeration fluid after heating the fluid with a heat exchanger. The reclaimed ammonia is returned to the ammonia refrigeration system where it is reused. Waste fluid from the ammonia still apparatus is collected and dumped.

1 . An ammonia still apparatus for an ammonia refrigeration system, comprising: 
 a liquid inlet;    a tank in fluid communication with the liquid inlet;    an ammonia discharge line in fluid communication with the tank;    a heat exchanger in fluid communication with the tank;    an upper temperature sensor being located between the tank and the heat exchanger;    an upper liquid sensor in fluid communication with the tank;    a waste fluid outlet in fluid communication with the heat exchanger;    a lower liquid sensor in fluid communication with the waste fluid outlet;    a water/oil discharge line in fluid communication with the waste fluid outlet;    a lower temperature sensor being located between the heat exchanger and the water/oil discharge line.    
   
   
       2 . An ammonia still apparatus of  claim 1 , further comprising: 
 a PLC in communication with the upper and lower temperature sensors and the upper and lower liquid sensors.    a liquid solenoid in fluid communication with the liquid inlet and in communication with the PLC; and    a suction solenoid in fluid communication with the ammonia discharge line and in communication with the PLC.    
   
   
       3 . An ammonia still apparatus of  claim 2 , wherein the water/oil discharge line further comprises: 
 a waste dump solenoid in communication with the PLC; and    a flow meter in communication with the PLC.    
   
   
       4 . An ammonia still apparatus of  claim 3 , wherein the upper liquid sensor is a float switch in communication with the PLC, and the lower liquid sensor is a liquid switch in communication with the PLC.  
   
   
       5 . An ammonia still apparatus of  claim 4 , further comprising: 
 an oil skimmer tank in fluid communication with the water/oil discharge line; and    a water fill solenoid in communication with the PLC and in fluid communication with the oil skimmer tank.    
   
   
       6 . An ammonia still apparatus of  claim 1 , further comprising: 
 further comprising:    a hot gas inlet in fluid communication with the upper end of the heat exchanger; and    a discharge outlet in fluid communication with the lower end of the heat exchanger.    
   
   
       7 . An ammonia still apparatus of  claim 6 , further comprising: 
 a PLC in communication with the upper and lower temperature sensors and the upper and lower liquid sensors;    a liquid solenoid in fluid communication with the liquid inlet and in communication with the PLC;    a suction solenoid in fluid communication with the ammonia discharge line and in communication with the PLC; and    a waste dump solenoid in fluid communication with the water/oil discharge line and in communication with the PLC.    
   
   
       8 . An ammonia still apparatus of  claim 7 , further comprising: 
 a flow meter in fluid communication with the water/oil discharge line and in communication with the PLC;    an oil skimmer tank in fluid communication with the water/oil discharge line; and    a water fill solenoid in communication with the PLC and in fluid communication with the oil skimmer tank.    
   
   
       9 . An ammonia still apparatus of  claim 8 , wherein the upper liquid sensor is a float switch in communication with the PLC, and the lower liquid sensor is a liquid switch in communication with the PLC.  
   
   
       10 . An ammonia still apparatus for an ammonia refrigeration system, comprising: 
 a PLC;    a liquid inlet being in fluid communication with the refrigeration system and having a liquid solenoid in communication with the PLC;    a tank in fluid communication with the liquid inlet;    an upper liquid float switch in fluid communication with the tank;    an ammonia discharge line in fluid communication with the tank and the refrigeration system and having a suction solenoid in communication with the PLC;    a heat exchanger in fluid communication with the tank;    an upper temperature sensor being located between the tank and the heat exchanger;    a waste fluid outlet in fluid communication with the heat exchanger;    a lower liquid sensor in fluid communication with the waste fluid outlet and in communication with the PLC;    a water/oil discharge line in fluid communication with the waste fluid outlet and having a water dump solenoid in communication with the PLC; and    a lower temperature sensor being located between the heat exchanger and the water/oil discharge line and in communication with the PLC.    
   
   
       11 . An ammonia still apparatus for an ammonia refrigeration system of  claim 10 , further comprising: 
 a hot gas inlet in fluid communication with the upper end of the heat exchanger and having a hot gas solenoid in communication with the PLC; and    a discharge outlet in fluid communication with the heat exchanger and having a discharge solenoid in communication with the PLC.    
   
   
       12 . An ammonia still apparatus for an ammonia refrigeration system of  claim 11 , wherein the hot gas inlet and the discharge outlet are in fluid communication with the refrigeration system.  
   
   
       13 . An ammonia still apparatus for an ammonia refrigeration system of  claim 12 , wherein the water/oil discharge line further comprises: 
 a water dump solenoid;    a flow meter; and    wherein the water fill solenoid, the water dump solenoid, and the flow meter are in communication with the PLC    
   
   
       14 . An ammonia still apparatus for an ammonia refrigeration system of  claim 13 , further comprising: 
 an oil skimmer tank in fluid communication with the water/oil discharge line; and    a water fill solenoid in fluid communication with the PLC.    
   
   
       15 . An ammonia still apparatus for an ammonia refrigeration system of  claim 14 , further comprising: 
 an oil receiver; and    an oil line between the oil skimmer tank and the oil receiver, the oil line having an oil flow meter in communication with the PLC.    
   
   
       16 . A method of purifying ammonia from contaminated refrigeration fluid in an ammonia refrigeration system, the method comprising the steps of: 
 (a) allowing contaminated refrigeration fluid from the refrigeration system to flow into the tank;    (b) heating the contaminated refrigeration fluid from the tank with a heat exchanger and preventing the contaminated refrigeration fluid from flowing into the tank during heating;    (c) measuring the contaminated refrigeration fluid level in the tank;    (d) separating anhydrous ammonia from the contaminated refrigeration fluid;    (e) removing the separated anhydrous ammonia;    (f) returning the removed anhydrous ammonia from the tank to the ammonia refrigeration system;    (g) measuring an upper temperature of the contaminated refrigeration fluid between the tank and the heat exchanger;    (h) measuring a lower temperature of the waste fluid after leaving the heat exchanger;    (i) measuring a tank fluid level in the tank;    (j) discharging waste fluid from the heat exchanger once the upper temperature and the lower temperature are equal and the tank fluid level reaches a set maximum tank fluid level; and    (k) preventing contaminated refrigeration fluid from flowing into the tank and anhydrous ammonia from leaving the tank during the discharge of waste fluid.    
   
   
       17 . A method of purifying ammonia from contaminated refrigeration fluid in an ammonia refrigeration system of  claim 16 , further comprising the steps of 
 (l) measuring a waste fluid level of the waste fluid after leaving the heat exchanger; and    (m) preventing the waste fluid from discharging once the waste fluid level reaches a set lower waste fluid level point.    
   
   
       18 . A method of purifying ammonia from contaminated refrigeration fluid in an ammonia refrigeration system of  claim 17 , further comprising the steps of: 
 (n) collecting the waste fluid in an oil skimmer tank;    (o) separating oil and water from the waste fluid;    (p) removing the oil; and    (q) removing the water.    
   
   
       19 . A method of purifying ammonia from contaminated refrigeration fluid in an ammonia refrigeration system of  claim 17 , further comprising the steps of: 
 (n) circulating hot gas in the heat exchanger;    (o) discharging hot gas condensate from the heat exchanger; and    (p) preventing hot gas from circulating and hot gas condensate from discharging during the discharge of waste fluid.    
   
   
       20 . A method of purifying ammonia from contaminated refrigeration fluid within an ammonia refrigeration system, the method comprising the steps of: 
 (a) opening a liquid solenoid and allowing the contaminated refrigeration fluid to flow into a tank from the refrigeration system;    (b) opening a suction solenoid and allowing anhydrous ammonia to flow from the tank into the ammonia refrigeration system;    (c) measuring a tank fluid level of the contaminated refrigeration fluid level within the tank with an upper liquid sensor;    (d) communicating the measured tank fluid level to a PLC;    (e) heating contaminated refrigeration fluid from the tank with a heat exchanger;    (f) closing the liquid solenoid during heating with the heat exchanger;    (g) separating anhydrous ammonia from the contaminated refrigeration fluid in the heat exchanger;    (h) sending the separated anhydrous ammonia into the refrigeration system;    (i) measuring an upper temperature of the contaminated refrigeration fluid between the tank and the heat exchanger;    (j) measuring a lower temperature of the waste fluid after leaving the heat exchanger;    (k) communicating the measured upper and lower temperatures to the PLC;    (l) measuring a waste fluid level of the waste fluid with a lower liquid sensor communicating with the PLC; and    (m) opening a waste dump solenoid and discharging waste fluid from the heat exchanger after the upper and lower temperatures are equal and the tank level reaches a maximum tank level;    (n) closing the liquid solenoid and the suction solenoid during waste fluid removal; and    (o) wherein the PLC communicates with at least one of the solenoids to open and close the solenoids.    
   
   
       21 . A method of purifying ammonia from contaminated refrigeration fluid in an ammonia refrigeration system of  claim 20 , further comprising the steps of 
 (p) measuring a waste fluid level of the waste fluid after leaving the heat exchanger; and    (q) closing the waste dump solenoid once the waste fluid level reaches a set lower waste fluid level point.    
   
   
       22 . A method of purifying ammonia from contaminated refrigeration fluid in an ammonia refrigeration system of  claim 21 , further comprising the steps of: 
 (r) collecting waste fluid in an oil skimmer tank;    (s) separating oil and water from the waste fluid;    (t) removing the oil; and    (u) removing the water.    
   
   
       23 . A method of purifying ammonia from contaminated refrigeration fluid in an ammonia refrigeration system of  claim 21 , further comprising the steps of: 
 (r) opening a hot gas solenoid;    (s) circulating hot gas in the heat exchanger;    (t) opening a discharge solenoid to dispose of condensate from the heat exchanger; and    (u) closing the hot gas and discharge solenoids during waste fluid removal.