Intertwined coil heat exchanger

A reactor (70) for supercritical water oxidation, said reactor comprising:

• a reactor wall (71) forming a reactor enclosure (78), said reactor wall (71) configured to withstand pressure and temperature in the supercritical region of water, and
• a heat exchanger (1) enclosed in the interior of said reactor enclosure (78), the heat exchanger (1) including:
• a plurality of tubular fluid channels (10, 20, 30) each having:
• an external tubular diameter (14, 24) or equivalent diameter;
• two openings (12, 13, 22, 23) into the interior of the tubular fluid channel, said openings being arranged at distant end positions of the fluid channel;
• wherein
• each of the plurality of tubular fluid channels (10, 20, 30) are formed as a coil (11, 21, 31), such as a helical coil (11, 21, 31), over at least a part of their lengths, each coil (11, 21, 31) being provided as a plurality of windings (15, 25) each of said coils (11, 21, 31) evolving with a centre path (16, 26, 36);
• the coils (11, 21, 31) of the plurality of tubular fluid channels (10, 20, 30) are intertwined around one another with the centre path (16, 26, 36) of each coil being distant from the centre path (16, 26, 36) of the other coils (11, 21, 31), and each of the centre paths (16, 26, 36) forms a helix, and
• in a transverse cross section of the heat exchanger (1), a planar representation (18, 28, 38) of a winding of a first of said coils (11, 21, 31) overlaps a planar representation (18, 28, 38) of a winding of each of the other said coils (11, 21, 31) of said plurality of tubular fluid channels (10, 20, 30).