延迟焦化装置水系统能耗分析及改造措施

An Analysis of Energy Consumption of Water System of Delayed Coking Unit

现有工艺下,延迟焦化装置在燃料气和蒸汽方面的节能潜力非常有限,虽然水系统能耗仅占延迟焦化装置总能耗的5%-6%,但是优化空间较大。以某延迟焦化装置为例,通过对水系统能耗构成进行分析发现,除氧水、除盐水能耗系数较大,是重点优化对象;而装置自产凝结水和净化水却未能得到有效利用。因此,制定并实施了水系统改造方案：用凝结水替代蒸汽发生器之前使用的除氧水;用净化水替代富气水洗工艺之前使用的除盐水、焦炭塔之前使用的冷焦水以及冷焦水缓冲罐水封罐、酸性水罐水封罐和贫液水封罐等之前使用的循环水;根据换热冷却器进、出口水温,将循环水串联使用。改造实施后,节水降耗效果明显,除氧水、除盐水和循环水能耗降幅分别达到35.48%、32.50%和10.49%,水系统总能耗降幅达到20.15%。

A delayed coking unit now has very limited potential for saving fuel gas and steam.Although a water system accounts for only 5%-6% of the total energy consumption of a delayed coking unit,there is big room for optimization of such system.Take a delayed coking unit,unit A,for example.After analyzing the composition of energy use by a wate system,researchers found that deoxidized water and demineralized water had relatively large coefficients of energy dissipation and were therefore the key objects of optimization.The con-densed water and purified water produced by the unit were not utilized effectively.These researchers devel-oped and implemented a water system revamping scheme-substituting condensed water for deoxidized water previously used by the steam generator;substituting purified water for deoxidized water previously used by the rich gas water scrubbing process,coke cooling water previously used by the coking tower and circulating water previously used by water-sealed tanks such as coke cooling water buffer tanks,acidic water tanks and barren liquor tanks;and using circulating water in series according to the temperature of water at the inlet and outlet of the heat exchange cooler.The revamping produced excellent results in terms of water and ener-gy saving.The energy consumption of the deoxidized water,demineralized water and circulating water systems dropped by 35. 48 %, 32. 50 % and 10. 49 %, respectively. The water system ′ s total energy consumption fell20.15%.