Biodiesel production

Abstract

A reactor includes a shell having an input port configured to receive a reaction mixture and an output port configured to discharge a reaction product and a plug within the shell, the sintered plug having a first catalyst configured to transform the reaction mixture into the reaction product, the plug having pores of at least 0.01 micrometers (μm) diameter. A conduit includes a first and second lumen, the first lumen configured to carry a first fluid in a first direction and the second lumen configured to carry a second fluid in a second direction, the first lumen helically twisted relative to the second lumen, and the first lumen configured to conductively transfer thermal energy to the second lumen. A system includes a reactor with a sintered plug and a heat exchanger including a first and a second lumen helically intertwined about an axis.

What is claimed is: 
     
         1 . A system, comprising:
 a heat exchanger including a first lumen and a second lumen helically intertwined about an axis; and   a reactor including a sintered plug in a vessel in fluid communication with the first pipe and the second pipe, the plug having pores of at least 0.01 micrometers (μm) diameter and the plug configured to catalyze a reaction.   
     
     
         2 . The system of  claim 1 , wherein the reactor is configured to operate at a temperature of up to 500 degrees Celsius (° C.). 
     
     
         3 . The system of  claim 1 , wherein the reactor is configured to operate at a pressure of at least 8.3 megapascals (MPa). 
     
     
         4 . The system of  claim 1 , including a heater is in fluid communication with the first pipe and configured to add thermal energy to the system. 
     
     
         5 . The system of  claim 1 , wherein the system is configured to be transportable. 
     
     
         6 . The system of  claim 1 , wherein the sintered plug includes stainless steel. 
     
     
         7 . A conduit, comprising a first lumen and a second lumen, the first lumen configured to carry a first fluid in a first direction and the second lumen configured to carry a second fluid in a second direction, the first lumen is helically twisted relative to the second lumen, and the second lumen configured to conductively transfer thermal energy to the first lumen for a substantial portion of a length of the conduit. 
     
     
         8 . The conduit of  claim 7 , wherein the first lumen includes a first metal tube and the second lumen includes a second metal tube. 
     
     
         9 . The conduit of  claim 8 , wherein the first metal tube and the second metal tube have a thermal interface formed by a thermally conducting filler material. 
     
     
         10 . The conduit of  claim 7 , wherein the first metal tube has a first wall, the first wall having a first flat region on an external surface, and the second metal tube has a second wall, the second wall having a second flat region on an external surface, the first flat region and the second flat region joined along the substantial portion. 
     
     
         11 . The conduit of  claim 7 , wherein the first direction is different than the second direction. 
     
     
         12 . The conduit of  claim 7 , wherein the substantial portion has a first segment with a first axis and a second segment with a second axis, the first axis different than the second axis. 
     
     
         13 . A reactor, comprising:
 a shell having an input port configured to receive a reaction mixture and an output port configured to discharge a reaction product; and   a sintered plug within the shell, the sintered plug having a first catalyst, the first catalyst configured to transform the reaction mixture into the reaction product, the plug having pores of at least 0.01 micrometers (μm) diameter.   
     
     
         14 . The reactor of  claim 13 , wherein the first catalyst includes stainless steel. 
     
     
         15 . The reactor of  claim 13 , wherein the reaction mixture includes an alcohol and a lipid. 
     
     
         16 . The reactor of  claim 15 , wherein the alcohol includes a C1-C6 alcohol. 
     
     
         17 . The reactor of  claim 15 , wherein the lipid includes at least one of a plant oil or an animal fat. 
     
     
         18 . The reactor of  claim 13 , wherein the sintered plug has pores of at most 100 μm diameter. 
     
     
         19 . The reactor of  claim 13 , wherein the sintered plug includes a second catalyst, including a heterogeneous non-consumed particle. 
     
     
         20 . The reactor of  claim 19 , wherein the second catalyst includes at least one of sintered ore, sintered zirconia, sintered titania, and sintered alumina. 
     
     
         21 . A method for biodiesel production, comprising:
 providing a reaction mixture to a heat exchanger, the reaction mixture including a lipid and an alcohol;   pre-heating the reaction mixture in the heat exchanger, wherein the heat exchanger includes a first pipe including the reaction mixture, the first pipe helically intertwined about an axis with a second pipe, wherein the second pipe includes a reaction product of a biodiesel reaction; and   reacting the reaction mixture in a reactor a supercritical condition to produce the reaction product, wherein the reactor includes a sintered plug in a vessel fluidly coupled to the first pipe and to the second pipe, the plug having pores of at least 0.01 micrometers (μm) diameter and the plug configured to catalyze a reaction.   
     
     
         22 . The method of  claim 21 , wherein reacting the reaction mixture comprises the biodiesel reaction of transesterification and esterification. 
     
     
         23 . The method of  claim 21 , wherein the super critical condition includes a pressure of about 8.3 MPa to about 35 MPa. 
     
     
         24 . The method of  claim 21 , wherein the reaction mixture includes an excess of alcohol to lipid. 
     
     
         25 . The method of  claim 21 , wherein the lipid includes a free fatty acid concentration of up to about 60 wt %. 
     
     
         26 . The method of  claim 21 , wherein the lipid includes a water concentration of up to about 10 wt %. 
     
     
         27 . The method of  claim 21 , including:
 recovering excess alcohol from the reaction product; and   recycling the recovered excess alcohol to an alcohol input tank or an alcohol reclamation tank.   
     
     
         28 . The method of  claim 21 , including reacting the reaction product, after reacting the reaction mixture, in a supplemental reactor in series with the reactor.