Abstract: Para-xylene is the main target product in xylene unit of aromatics unit, but its energy consumption is high. Taking the common problems of restricting energy efficiency of xylene unit as the breakthrough point，the heat exchange process of xylene unit was optimized to reduce the fuel gas consumption of the reboiler of xylene column. A new type of wound tube heat exchanger was developed to improve the design accuracy of heat exchanger. At the same time，the low temperature heat recovery network system of xylene unit was systematically designed，which significantly reduced the energy consumption of the unit. The industrial application results showed that the total amount of fuel gas consumption was reduced by 0.87 t/h, the low-temperature heat was recovered by 29.56 MW, and the comprehensive energy consumption was reduced by 3 118.6 MJ/t，greatly improving the energy efficiency of the xylene unit, and the energy-saving modification of xylene plant is of guiding significance.

Key words: p-xylene unit, heat integration, wound tube heat exchanger, low temperature heat