Modeling of a fixed bed reactor for non-catalytic solid-gas reactions

Karşı-akışlı sabit-yatağın 1-Boyutlu modeli, değişken sıcaklık şartlarında, katı-gaz reaksiyonları ve reaksiyon ışılan temel alınarak geliştirilmiştir. "Pseudo" kararlı-durum yaklaşımı, farklı gaz ve katı sıcaklıklarını dikkate almaktadır. Yataktaki katılar "plug" akışına göre yükselen gaz yığınına karşı hareket ederken, parçacık, reaksıyonsuz büzülen çekirdek modelini izler. Katı-yançap denklemi ve ısı ve kütle aktarımı için elde edilen nonlineer adi diferansiyel denklemler çifti, yan-kapalı Üçlü Bant Matris Algoritması kullanılarak eş-zamanlı çözülmüşlerdir. Bunun yanı sıra, katı tüketimi için dönüşüm zamanı, "Simpson" sayısal integrasyon tekniği kullanılarak hesaplanmıştır. Katı debisinin hem dönüşüm zamanına hem de dönüşüm oranına olan etkileri incelenmiştir.

ABSTRACT A one-dimensional model of a countercurrent fixed-bed based on solid- gas reactions and heats of reactions under non-isothermal conditions has been developed. A pseudo steady-state approximation considers separate gas and solid temperatures. A particle follows the unreacted-core shrinking model while solids move in the bed according to a plug flow countercurrent to raising bulk of gases. The solid-radius equation and coupled nonlinear ordinary differential equations for heat and mass transfer are simultaneously solved using semi-implicit Tri-Diagonal Matrix Algorithm A Conversion time for the consumption of solid is also computed by Simpson's rule of numerical integration technique. Effects of solid flow rate on both the conversion time and the conversion ratio are investigated.

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