Closed oil liquid ring gas compression system with a suction injection port

Abstract

A gas compressor system draws and compresses gas from a well, wherein the gas has entrained liquid and vapor. The apparatus has a scrubber vessel for receiving the gas and separating at least a portion of the liquid. A storage vessel integral with the scrubber stores seal liquid. The seal liquid is injected into the gas before a single stage liquid ring pump which uses the seal liquid to compress the gas. The compressed gas along with entrained seal liquid is routed to a separator vessel having a coalescing filter. The entrained seal liquid is separated from the gas and routed back to the storage vessel.

We claim:  
     
       1. An apparatus for compressing a gas from a well, the gas having entrained hydrocarbon liquid, the apparatus comprising: 
       a scrubber vessel for receiving gas from a well and gravity separating at least a portion of any entrained hydrocarbon liquid from the gas;  
       a liquid ring pump having an inlet connected to the scrubber vessel for creating a negative pressure in the scrubber vessel to draw gas from the well and for compressing the gas to a desired pressure;  
       a seal liquid line connected to the inlet of the pump for delivering a seal liquid to the inlet of the pump for mixing with the gas prior to being compressed; and  
       a separator vessel connected to an outlet of the pump for separating the seal liquid entrained in the gas, retaining the separated seal liquid to the seal liquid line, and for discharging the compressed gas to a gas outlet line, the separator vessel having a lower portion for collecting the separated seal liquid and an upper portion with an outlet adapted to be connected to the gas outlet line;  
       
         a filter located in the upper portion of the separator vessel for separating the seal liquid entrained in the gas; and  
       
         a scavenger line running from a lower portion of the filter in the separator vessel to a conduit between the scrubber vessel and the pump, the scavenger line being free of any restrictive orifices so that the scavenger line will lower pressure in the separator vessel to increase a flow rate of the gas through the separator vessel .  
     
     
       2. The apparatus of  claim 1  wherein: 
       the scrubber vessel has a first and second separate chambers, wherein the first chamber receives the gas from the well; and  
       the seal liquid line has a first portion extending from the separator vessel to the second chamber and a second portion extending from the second chamber to the inlet of the pump, to store the seal liquid in the second chamber.  
     
     
       3. The apparatus of  claim 2  wherein the scrubber vessel has an internal partition which divides the scrubber vessel into the first and second chambers. 
     
     
       4. The apparatus of  claim 1  wherein the separator vessel has  filter is a coalescing filter that further separates the seal liquid from the gas . 
     
     
       5. The apparatus of  claim 4  wherein the separator vessel further comprises a splash guard adjacent the coalescing filter, the splash guard having a wall positioned adjacent an inlet leading from the outlet of the pump for blocking the filter from contact with a stream of the gas and entrained seal liquid flowing from the pump. 
     
     
       6. The apparatus of  claim 5  wherein the splash guard is cylindrical and spaced inward from the inlet. 
     
     
       7. The apparatus of  claim 4  wherein the separator vessel has a  scavenger line running from the coalescing filter to a conduit between the scrubber vessel and the pump, for lowering pressure in the separator vessel to increase a flow rate of the gas through the separator vessel  extends through an upper end of the separator vessel downward into the filter. 
     
     
       8. The apparatus of  claim 1  wherein the liquid ring pump is single stage having a single inlet and single outlet. 
     
     
       9. The apparatus of  claim 1  wherein the seal liquid is a hydraulic oil. 
     
     
       10. The apparatus of  claim 9  wherein the seal liquid is an oil with an SAE 10W or higher viscosity grade. 
     
     
       11. The apparatus of  claim 1  further comprising a heat exchanger and temperature responsive valve in the seal liquid line, wherein the temperature responsive valve routes the seal liquid from the separator through the heat exchanger for cooling before mixing with the gas if the temperature of the seal liquid is above a given temperature. 
     
     
       12. A device for producing gas from a well, the gas having entrained liquid and vapor, the device comprising: 
       a scrubber vessel having a housing containing a primary chamber separated from a secondary chamber, wherein the primary chamber is adapted to receive gas and entrained liquid from a well to separate by gravity at least some of the liquid from the gas, and the secondary chamber is adapted to store a seal liquid;  
       a liquid ring pump having an inlet connected to the primary and secondary chambers of the scrubber vessel for using the seal liquid to compress the gas, wherein the seal liquid and the gas are mixed before entering the pump;  
       a separator vessel having an inlet connected to an outlet of the pump for separating any seal liquid from the gas and discharging the gas to an outlet line, the separator vessel being cylindrical, having a vertical axis and an upper end, the inlet of the separator vessel being located adjacent the upper end of the separator vessel; and  
       a cup- shaped coalescing filter located in the separator vessel adjacent the upper end of the separator vessel;    
       a seal liquid line leading from a lower portion of the separator vessel to the secondary chamber for returning the separated seal liquid;  
       
         a gas outlet line leading from the upper end of the separator vessel for discharging gas that has flowed through the coalescing filter; and  
       
         a scavenger line extending through the upper end of the separator vessel downward into the coalescing filter and running from the separator vessel to a conduit between the scrubber and the pump, the scavenger line being free of any restrictive orifices so that the scavenger line will lower pressure in the coalescing filter to increase a flow rate of the gas out the gas outlet line .  
     
     
       13. The device of  claim 12  wherein the separator vessel has a coalescing filter that further separates the seal liquid from the gas. 
     
     
       14. The device of claim  13   12 wherein the separator vessel further comprises a splash guard adjacent the coalescing filter, the splash guard having a wall positioned adjacent an inlet leading from the outlet of the pump for blocking the filter from contact with a stream of the gas and entrained seal liquid flowing from the pump. 
     
     
       15. The device of  claim 14  wherein the splash guard is cylindrical and spaced inward from the inlet. 
     
     
       16. The device of  claim 13  further comprising a scavenger line running from the coalescing filter to a conduit between the scrubber and the pump, for lowering pressure in the separator vessel to increase a flow rate of the gas. 
     
     
       17. The device of  claim 12  wherein the primary chamber has an outlet leading to the pump that is located above an inlet adapted to receive the gas from the well. 
     
     
       18. The device of  claim 12  wherein the liquid ring pump is single stage having a single inlet and single outlet. 
     
     
       19. The device of  claim 12  wherein the seal fluid is a hydraulic oil. 
     
     
       20. A method of compressing wet gas from a well, the wet gas having entrained liquid, comprising the steps of: 
       with a liquid ring pump, creating a suction at an inlet of the pump to draw the gas from the well into a suction scrubber, creating a gas stream flowing through the scrubber to the pump;  
       injecting a seal liquid into the gas stream before it enters the liquid ring pump;  
       compressing the gas with the seal liquid in the liquid ring pump; and  
       separating at least a portion of any seal liquid from the gas in a discharge separator by gravity and with a coalescing filter in the discharge separator, and feeding the separated seal liquid back into the gas stream before it enters the liquid ring pump;  
         extending a scavenger line free of any restrictions into the coalescing filter in the discharge separator and to a conduit extending between the scrubber and the pump .  
     
     
       21. The method of  claim 20  further comprising the step of cooling the seal liquid after leaving the discharge separator and before injection into the gas stream. 
     
     
       22. The method of  claim 20  further comprising the steps of: 
       providing a partition in the suction scrubber to form a primary chamber for receiving the gas from the well and a secondary chamber; and  
       delivering seal liquid from the separator to the secondary chamber and delivering seal liquid from the secondary chamber to the gas stream flowing into the inlet of the pump.  
     
     
       23. A device for producing gas from a well, the gas having entrained liquid and vapor, the device comprising: 
       
         a scrubber vessel having a housing containing a primary chamber separated from a secondary chamber, wherein the primary chamber is adapted to receive gas and entrained liquid from a well to separate by gravity at least some of the liquid from the gas, and the secondary chamber is adapted to store a seal liquid;  
       
       
         a liquid ring pump having an inlet connected to the primary and secondary chambers of the scrubber vessel for using the seal liquid to compress the gas, wherein the seal liquid and the gas are mixed before entering the pump;  
       
       
         a separator vessel connected to an outlet of the pump for separating any seal liquid from the gas and discharging the gas to an outlet line, the separator vessel having a lower portion for collecting the separated seal liquid;  
       
       
         a coalescing filter located in an upper portion of the separator for further separating the seal liquid from the gas;  
       
       
         a seal liquid line leading from the lower portion of the separator vessel to the secondary chamber for returning the separated seal liquid; and  
       
       
         a scavenger line running from a bottom of the coalescing filter to a conduit between the scrubber and the pump, the scavenger being free of any restrictive orifices so as to communicate lower pressure in the conduit to the coalescing filter for lowering pressure in the separator vessel to increase a flow rate of the gas.