芳烃联合装置精馏塔低温工艺余热利用可行性分析

An Analysis of Feasibility of Utilization of Aromatics Distillation Process Low-temperature Waste Heat

中国石化洛阳分公司芳烃联合装置由芳烃抽提、苯抽提蒸馏、对二甲苯、PSA制氢装置及产品罐区等构成,其核心装置为芳烃抽提和对二甲苯装置。通过分析芳烃联合装置精馏塔塔顶物料对水的安全性能,同时对重整油分馏塔、歧化与烷基转移苯塔、重芳烃塔、成品塔和脱庚烷塔塔顶油气工艺余热进行计算,提出以水为热媒、将热媒水送至热电站加热产汽用的除盐水余热综合利用方案。通过计算,可利用五精馏塔低温工艺余热103246.49MJ/h,折合标油为2466kg/h,芳烃联合装置"三苯"产量以42t/h计算,可降低装置能耗58.7个单位,节能效果明显。同时,可将545t/h的除盐水由20℃加热至65℃,降低加热除盐水消耗的1.0MPa蒸汽20.64t/h。按照1.0MPa蒸汽175元/t、年运行8400h计算,年实现经济效益3034×104元。对利用五精馏塔工艺余热项目进行投资估算,需投资合计约4860×104元,而该项目年实现经济效益达3034×104元,即投资回收期约1.6a。

Sinopec Luoyang Company＇s integrated arene unit consists of the arene extraction section,the benzene extraction and distillation section,the paraxylene section,PSA hydrogen production section and product tanks.At the heart of the unit are the arene extraction and paraxylene units.By analyzing the effect of the materials on the top of the rectifying columns of the integrated arene unit on the safety of water and calcu- lating the residual heat from the oil and gas processes at the top of the reformate fractioning tower, the dis- proportionation and transalkylation column,the heavy aromatics column,the finished product column and the heptane removing column,this article proposes an integrated residual heat utilization plan in which water is transmitted as heating medium to steam power plants to heat demineralized water used for producing steam. Calculations show that 103246.49MJ/h of low-temperature residual heat from five rectifying columns can be utilized,which is equivalent to 2466kg/h of oil.Assuming the combined output of benzene ,methyl benzene and dimethylbenzene is 42t/h,the integrated arene unit＇s energy consumption could drop by 58.7 units.In addi- tion,the temperature of the 545t/h demineralized water can be raised to 65℃ from 20℃ .As a resuh,the consumption of 1.0Mpa steam used for heating the demineralized water would drop by 20.64t/h.Assuming the price of the 1.0MPa steam is 175 yuan/t and the unit will operate 8400 hours per year,annual economic benefits will reach 3034×10^4 yuan.A project utilizing residual process heat from rectifying columns is expected to cost around 4860×10^4 yuan and annual returns on the project are expected to hit 3034×10^4,meaning that investment will be recovered in about 1.6 years.