催化裂化再生器外取热器分类及换热性能分析

从换热过程的内在规律出发,将已投用的外取热器分为阀控上流式、阀控下流式、气控下流式、无循环式 共４种形式;提出了热量分解概念,外取热器热量由对流热和当量“扩散热”两部分组成。已投用的外取热器中,气 控式设备效率最高,单位外取热器设备体积取热量为 ０、４５ ＭＷ／ｍ~３,其他形式为 ０．３ ＭＷ／ｍ~３,再考虑滑阀造价,气控 式投资明显低于阀控式;对应同样的流化气速和催化剂循环量,气控式能提供更高的催化剂温度及更大的换热强 度;各种取热器均可用肋片强化,肋片效率一般在０．７左右。

CLASSIFICATION AND HEAT TRANSFER ANALYSIS OF EXTERNAL COOLER IN REGENERATOR OF FCCU

The external catalyst coolers in the regenerator of FCCU can be classified as 4 types as the valve- control up-flow type, valve-control down-flow type, pneumatic down-flow type and nonrecycled type depending on the inherent law of heat transfer. The concept of heat decomposition was put forward. Heat to the external cooler consists of both convection heat and equivalent "diffusion heat". Among the external coolers in service, the pneumatic type has the best efficiency and its heat transfer capacity is 0. 45MW/m~3. But the others are 0. 30MW/m~3. The cost of the pneumatic type is much lower than that of the valve-control type. Under conditions of same fluidized gas velocity and same catalyst circulation rate, the pneumatic type can supply much higher catalyst temperature and heat transfer strength. Various types of external coolers can be strengthened by fins. In general, the fins efficiency is about 0. 7