Crude distillation (CDU) simulation

1 crude feed -> distillate + side cuts + bottoms (in order)

Parameters

n_stages, feed_stage, reflux_ratio, distillate_to_feed [0..1], pressure [Pa], side_draws [[{stage, fraction}] — liquid cuts taken at trays between feed and top; distillate+draws fractions must sum < 1]. Outlets/edges in order: distillate, cuts…, bottoms. Use with petroleum-cut components / pseudocomponents under peng-robinson.

Example flowsheets that use it