Liquid to liquid multi-pass countercurrent heat exchanger

A heat exchanger, comprising:

• a shell forming a generally cylindrical housing having an inner surface;
• a plurality of dividers within the shell longitudinally extending along the length of the shell and extending axially outward from the center region of the shell toward the inner surface of the shell, the outer axial portion of each divider further comprising a connecting surface, wherein the connecting surface is positioned at an angle of about 85 to about 90 degrees from the divider, and the connecting surface is fixedly attached to the inner surface of the shell forming a hermetic seal, wherein the dividers separate the shell into sections and each section forms a shell pass;
• a plurality of tube passes, wherein at least one tube pass is contained within each of the shell passes, and each tube pass comprises a plurality of tubes extending along the length of the shell;
• a shell inlet passage configured to receive a first fluid into a first shell pass and a shell outlet passage configured to discharge the first fluid from a last shell pass;
• a plurality of shell pass passages formed in the dividers near a first end or a second end of the shell configured to allow flow of the first fluid from one shell pass to the next shell pass;
• a tube inlet passage configured to receive a second fluid into a first tube pass and a tube outlet passage configured to discharge the second fluid from a last tube pass;
• a pair of shell heads configured to couple to the first end and the second end of the shell, wherein each shell head is divided into a plurality of chambers and each chamber is configured to route flow of the second fluid from one tube pass to the next tube pass;
• and
• wherein a total cross-sectional area of the plurality of tubes of a tube pass is substantially equal to a total cross-sectional area outside the plurality of tubes of the tube pass and inside the corresponding shell pass.