To study the flow

heat transfer

and reaction performance of the microchannel multistream heat exchangers coupled with ortho–para hydrogen conversion

this work develops a one-dimensional model of heat exchanger

while considering the flow arrangement inside heat exchanger. The model reveals the temperature and pressure distributions across various streams in the exchanger and the changes in the concentration of para-hydrogen in the feed stream. The results show that the thermal load from ortho–para hydrogen conversion accounts for about one-third of the total thermal load of feed hydrogen. Increasing the feed hydrogen pressure is beneficial to reducing the heat transfer temperature difference

which can optimize heat transfer and reaction performance. When the temperature difference is reduced by 1.86 K

the outlet temperature decreases from 85.37 to 82.06 K

and para hydrogen concentration increases from 24.99% to 39.77%. Meanwhile

a larger heat transfer area is required. Proper allocation of thermal loads among the multiple cold streams is crucial to prevent performance deterioration. Further

simply increasing the reaction rate has a limited effect on performance

and the performance will be improved 83.45% while maintaining the heat exchanger area unchanged. This work provides a reference for designing multistream heat exchangers and lays the groundwork for continuous ortho–para hydrogen conversion in hydrogen liquefaction process simulations.