This work investigates the performances of a pillow-plate heat exchanger utilized as reactor for small-scale methanol synthesis. When downscaled, multi-tubular packed bed reactors are complicated to use since they undergo rapid losses in catalyst activity. A possible pathway to improve the unit performances is to diminish the tubes diameter and number. As this kind of reactors is governed by convective heat transfer, though, the use of long tubes is required to keep the mixture velocity high. This leads to the use of very long reactors, which cannot be easily realized with traditional designs. In order to tackle this issue, we propose the utilization of an innovative design, the pillow-plate reactor, increasing heat and mass transfer and the unit compactness. The study compares the performances of a packed-bed and a pillow-plate reactor through temperature profiles and methanol productivity at varying reactor lengths (1 – 6 m). It is proved that the pillow-plate unit, unlike the multi-tubular one, well manages scale reduction: when 1 m long reactors are employed, the outlet methanol fraction is close to equilibrium (5.8% vs. 4.9% for packed beds) and the hot-spots are well controlled (537 K vs. 557 K for tubular reactors). Moreover, it is also shown that the distance of metal layers in the pillow arrangement remarkably influences heat exchange, which is very effective for close layers, with a hot-spot of 518 K with a 3 mm gap, and much worse for the 12 mm design (552 K).

这项工作研究了用作小规模甲醇合成反应器的枕板式换热器的性能。当规模缩小时，多管式填充床反应器使用起来很复杂，因为它们的催化剂活性会迅速损失。提高装置性能的一个可能途径是减小管子直径和数量。然而，由于这种反应器是由对流传热控制的，因此需要使用长管来保持较高的混合物速度。这导致需要使用非常长的反应器，而传统设计无法轻松实现这一点。为了解决这个问题，我们建议采用创新设计，即枕板式反应器，增强传热传质以及装置的紧凑性。该研究通过不同反应器长度（1 – 6 m）下的温度分布和甲醇生产率来比较填充床和枕板反应器的性能。事实证明，与多管式装置不同，枕板式装置可以很好地减少结垢：当使用 1 m 长的反应器时，出口甲醇馏分接近平衡（填充床为 5.8%，填充床为 4.9%），并且热点得到很好的控制（管式反应器为 537 K，而管式反应器为 557 K）。此外，还表明枕形布置中金属层的距离显着影响热交换，这对于紧密层非常有效，间隙为 3 mm 时热点为 518 K，对于 12 mm 间隙则要差得多设计（552 K）。