川西北气矿甲醇厂蒸汽自平衡方案优化

Optimization schemes of steam/heat self-balance system in the methanol plant of PetroChina's Northwest Sichuan Gas Field

中国石油西南油气田公司川西北气矿甲醇厂1999年建成投产,但2003年后,自产蒸汽不能满足蒸汽系统平衡,只得低负荷运行开工锅炉,能耗提高。为此,运用PRO/Ⅱ软件对该厂转化系统、蒸汽系统进行了流程模拟,找到了蒸汽系统无法满足自平衡的原因——换热量下降导致转化汽包产汽量降低。在此基础之上,对转化气余热回收换热网络进行了优化,提出了解决蒸汽系统自平衡问题的技术方案。这为该厂进一步推进节能减排提供了技术保障。

The methanol plant of Northwest Sichuan Gas Field,PetroChina,was up and running in 1999.However,since 2003,the steam produced in this plant has not been able to meet the needs for steam/heat self-balance system so the boiler has to be under low-load operation with more energy to be consumed.Therefore,the PRO/Ⅱ software was adopted to simulate the flow process of transformation and steam systems in this plant,through which the reason was found for the above problem,that is,the transformed steam drum produced less steam due to the decrease of heat exchange amount.On the basis of this,the residual heat exchange network was optimized and two optimization schemes were proposed and evaluated respectively.The Scheme-Ⅰ adopts a heating boiler while the Scheme-Ⅱ adds a steam turbine set to recover the heat of residual low-pressure steam.The evaluation shows that the latter one is better for this plant to achieve a long-term profit in energy saving and emission reduction.