Abstract:
A pollution control system and method for a compressor for compressing gas, according to which a combustion engine is connected to the compressor for driving the compressor, and the products of combustion from the engine are passed into the flow line connecting the source of the gas to the compressor.

Description:
BACKGROUND  
       [0001]     This invention relates to a pollution control system and method for a gas compressor driven by an internal combustion engine.  
         [0002]     Gas compressors are used in the oil and gas industry to increase the fluid pressure in the flow lines for the oils and gases. Many of these compressors are driven by internal combustion engines which are often powered by natural gas.  
         [0003]     However, the exhaust, or flue, gases from the engine are usually vented to atmosphere causing excessive noise and particulate pollution. Also, since the combustion process is less than completely efficient, unspent fuel from the engine is also vented to atmosphere.  
         [0004]     Therefore, what is needed is a system for reducing this type of pollution and recover the unspent fuel. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0005]     The drawing is a diagrammatic view of an embodiment of the invention. 
     
    
     DETAILED DESCRIPTION  
       [0006]     Referring to  FIG. 1  of the drawings, the reference  10  refers, in general to a natural gas compressor connected in a main flow line  12  consisting of one or more pipes, conduits, risers, etc. The compressor  10  can be of any conventional type, such as a screw type, a rotary type, or the like.  
         [0007]     It is understood that the flow line  12  extends from a gas well (not shown) and that gases recovered from the well pass in the flow line in the direction indicated by the flow arrows. The gases thus flow from the well, through the flow line  12 , and to the compressor  10 , which functions to compress the gases. The compressed gases then pass from the compressor  10  through the flow line  12  for some downstream treatment that will be described, before the gases pass to their ultimate destination.  
         [0008]     The compressor  10  is driven by an internal combustion engine  14  in a manner to be described, and a branch line  12   a  extends from the flow line  12  upstream of the compressor  10  to the engine to pass a portion of the gases flowing in the flow line to the engine for powering the engine in a conventional manner. The engine  14  is conventional and, as such, generates products of combustion including exhaust, or flue gases. Also, since the combustion process in the engine  14  is less than completely efficient, unspent fuel, primarily in the form of hydrocarbons, is also present in the engine.  
         [0009]     The engine  14  is connected by a drive shaft  16  to the compressor  10  so that, when activated, the engine  14  drives the compressor  10  in a conventional manner. The engine  14  has an inlet for receiving the gases from the branch line  12   a  which serve as fuel to power the engine, and an outlet for discharging the products of combustion and the unspent fuel. A pipe, or conduit,  20  connects the outlet of the engine  14  to the flow line  12  upstream of the compressor  10  and downstream from the branch line  12   a . The pipe  20  passes the above products of combustion and any unspent fuel from the engine  14  to the flow line  12  where they are mixed with the well gases flowing through the flow line. The mixture thus passes into the compressor  10  and is compressed before the compressed mixture exits the compressor via the flow line  12 .  
         [0010]     The compressed mixture exiting from the compressor via the flow line  12  can be treated prior to being routed to its ultimate destination, or end user. For example, the H2O, CO2 and/or nitrogen from the products of combustion, and/or the unspent fuel in the mixture can be separated from the remaining portion of the, such as by resin re-absoption, or the like, and thus recaptured for reuse or disposal. This can be done in any conventional manner and at any convenient location, such as at the ultimate destination, or at a gas processing plant, a cryogenic plant, or the like, located between the compressor and the ultimate destination.  
         [0011]     Thus, the products of combustion from the engine  14  are not discharged into the atmosphere, but rather are mixed with the well gases being processed, thus avoiding any noise or particle pollution of the atmosphere. Also, the products of combustion can be separated from the mixture before the mixture is passed to the end user. Further, the unspent fuel, primarily in the form of hydrocarbons, from the engine  14  is not wasted, but rather is added to the product gases in the line  12  for use by the end user.  
         [0012]     It is understood that variations may be made in the foregoing without departing from the scope of the invention. For example, the particular designs of the compressor  10  and the engine  14  can be varied. Also, the engine  14  can be powered by fuel, such as diesel or gasoline, from a source other than the line  12 . Further, the branch line  12   a  and the pipe, or conduit,  20  can be connected to the line  12  at locations that are different from those shown in the drawings. Still further, the products of combustion from the engine  14  can be separated from the remaining portion of the above mixture before the mixture is compressed. Moreover, the terms “flow line”, “branch line”, “pipe”, “riser”, and “conduit” have been used interchangeably, and it is understood that all refer, in general, to any device that permits the flow of fluid therethrough.  
         [0013]     Although only one exemplary embodiment has been described in detail above, those skilled in the art will readily appreciate that many other variations and modifications are possible in the exemplary embodiment described above without materially departing from the novel teachings and advantages of this invention. Accordingly, all such variations and modifications are intended to be included within the scope of this invention as defined in the following claims. In the claims, means-plus-function clauses are intended to cover the structures described herein as performing the recited function and not only structural equivalents, but also equivalent structures.