一种新的评估MTO反应生焦量大小的方法

A new method for assessing the coke amount in MTO reaction

关键词:  甲醇制烯烃  生焦量  产汽过程  焓变 

Key words:  methanol to olefins (MTO)  coke amount  steam production process  enthalpy change

摘要:

从能量守恒角度对MTO反应生焦量的大小进行了评估。MTO反应过程中生成的焦炭附着在分子筛催化剂的活性中心上,导致催化剂失活,为恢复催化剂活性,催化剂需再生烧焦。由于焦炭燃烧释放的能量被用于生产蒸汽,所以计算生产蒸汽过程的焓变大小就能体现焦炭量的大小。利用工业上通用的水蒸气热力学性质计算公式IAPWS-IF97,对某企业MTO装置两个汽包在不同温度、压力条件下,产汽过程焓变进行计算。通过软件SigmaPlot 13.0对焓变数据进行处理,得出产汽过程焓值变化公式,进而得出单位质量甲醇由于生成焦炭而损失能量大小的公式,为调整MTO反应操作条件、降低生焦量提供了指导。 

Abstract:

The coke amount in the MTO reaction is evaluated from the perspective of energy conservation in this paper. The coke produced during the MTO reaction is attached to the active center of the molecular sieve catalyst, resulting in deactivation of the catalyst. To recover the catalyst activity, the catalyst is regenerated and burnt, and the heat released from char burning is used to produce steam. Therefore, calculating the size of the process of steam production will be able to reflect the size of the coke amount. Based on the formula IAPWS-IF97, which is a general calculation formula for the thermodynamic properties of steam in industry, the enthalpy change of steam production process at different temperature and pressure is calculated in the two steam drums of MTO unit. The enthalpy change data is processed by software SigmaPlot 13.0 and the formula of the enthalpy change of the steam production process is obtained, so the formula of the energy loss of the unit mass of methanol due to the formation of coke is received, which provides guidance for adjusting of the operating conditions of MTO reaction to reduce the coke amount.