Process and apparatus for removing oxygenates from liquefied petroleum gas

Abstract

A process and apparatus for removing oxygenates from a petroleum stream of C3 and/or C4 hydrocarbons comprises water washing the petroleum stream to absorb oxygenates to provide a hydrocarbon stream lean in oxygenates and a water stream rich in oxygenates. The water stream is stripped to remove oxygenates into an oxygenate concentrated stream and an oxygenate-lean water stream. The lean water stream can be recycled to the water wash column.

1 . A process for removing oxygenates from a petroleum stream of C3 and/or C4 hydrocarbons comprising:
 absorbing oxygenates from the petroleum stream into a water stream to produce a wash overhead stream rich in hydrocarbons and a wash bottoms stream rich in oxygenates; and   stripping said wash bottoms stream to produce a stripper overhead stream concentrated in oxygenates and a stripped water stream lean in oxygenates.   
     
     
         2 . The process of  claim 1  wherein said petroleum stream comprises fluid cracked product. 
     
     
         3 . The process of  claim 1  further comprising recycling said stripped bottoms stream as said water stream. 
     
     
         4 . The process of  claim 1  further comprising feeding make-up water to said absorbing step. 
     
     
         5 . The process of  claim 1  further comprising thermally oxidizing oxygenates in said stripper overhead stream. 
     
     
         6 . The process of  claim 5  recovering the energy via exchange with the process or steam generation. 
     
     
         7 . The process of  claim 1  further comprising removing hydrogen sulfide from said wash overhead stream. 
     
     
         8 . The process of  claim 1  further comprising removing nitriles from said wash overhead stream. 
     
     
         9 . The process of  claim 6  further comprising adsorbing residual oxygenates from said wash overhead stream in a bisulfide-wash column. 
     
     
         10 . The process of  claim 6  further comprising absorbing hydrogen sulfide with an alkaline solution to provide a desulfided wash stream and oxidizing mercaptans from said desulfided wash stream. 
     
     
         11 . The process of  claim 5  further comprising charging said stripper overhead stream to the thermal oxidizing step without undergoing condensation. 
     
     
         12 . The process of  claim 5  further comprising injecting dry sorbent to adsorb sulfur oxides from the flue gas from the thermal oxidizing step. 
     
     
         13 . The process of  claim 7  further comprising regenerating an adsorbent loaded with residual oxygenates with an alkane feed comprising 5 to 8 carbons. 
     
     
         14 . The process of  claim 1  further comprising heat exchanging said wash bottoms stream with said stripped bottoms stream. 
     
     
         15 . An apparatus for removing oxygenates from a petroleum stream comprising;
 a water wash column in communication with a petroleum stream and a water stream;   an oxygenate stripper column in downstream communication with a bottoms line from said water wash column; and   an acid gas removal column in downstream communication with an overhead line from said water wash column.   
     
     
         16 . The apparatus of  claim 13  further comprising a thermal oxidizer in downstream communication with an overhead line of said oxygenate stripper column. 
     
     
         17 . The apparatus of  claim 13  wherein the water wash column is in downstream communication with a bottoms line of the oxygenate stripper column to recycle water. 
     
     
         18 . The apparatus of  claim 13  further comprising an oxygenate adsorbent bed in downstream communication with an overhead line of said water wash column. 
     
     
         19 . The apparatus of  claim 16  further comprising a regenerant column in downstream communication with said oxygenate adsorbent bed during regeneration periods. 
     
     
         20 . A process for removing oxygenates from a petroleum stream of C3 and/or C4 hydrocarbons comprising:
 absorbing oxygenates from the petroleum stream into a water stream to produce a wash overhead stream rich in hydrocarbons and a wash bottoms stream rich in oxygenates;   stripping said wash bottoms stream to produce a stripper overhead stream concentrated in oxygenates and a stripped bottoms stream lean in oxygenates; and   recycling said stripped bottoms stream to said absorbing step as said water stream.   
     
     
         21 . The process of  claim 19  further comprising thermally oxidizing oxygenates in said stripper overhead stream.