Method for recovering benzene and toluene

A technology of benzene, toluene and toluene, applied in organic chemistry, distillation purification/separation, etc., can solve the problems of high temperature, increased investment, high operating temperature, etc., and achieve the effects of reduced energy consumption, less investment, and low energy consumption

Active Publication Date: 2009-06-03
SOUTHWEST RES & DESIGN INST OF CHEM IND
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

This can save energy, but due to the high operating pressure and high temperature of the pre-distillation tower, the equipment investment needs to be greatly increased. At the same time, due to the high operating temperature, the heat source requirements for the reboiler are also high, and high-temperature heating sources must be used. , the commonly used water vapor cannot be used for heating at all, and a substantial increase in investment is required to build a high-temperature heat carrier system, so the production cost is still high

Method used

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  • Method for recovering benzene and toluene

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0020] The method technological process of present embodiment reclaiming benzene and toluene is as figure 1 As shown, it mainly includes the following steps:

[0021] (1), pre-rectification: the raw material mixture 10 containing aromatics is preheated by heat exchangers 1 and 2 and enters the middle part of the pre-rectification tower 3; the raw material mixture 10 is 2947.85kg / h, wherein n-pentane 2.8kg / h h, cyclopentane 48.3kg / h, n-hexane 17.30kg / h, cyclohexane 14.25kg / h, n-heptane 4.4kg / h, methylcyclohexane 8.70kg / h, benzene 2197.64kg / h, Toluene 439.71kg / h, dimethylcyclohexane 3.85kg / h, n-octane 0.65kg / h, ethylcyclohexane 2.3kg / h, carbon 8 aromatics 162.95kg / h, carbon 9 or more hydrocarbons 45kg / h ; This pre-rectification tower 3 is a plate tower, and operating pressure is 0.3MPa (G) in the tower 3, and tower top temperature is 140 ℃, and feed position is in tower middle upper part, and reflux ratio R=1.3; From pre-rectification tower 3 Extract xylene and other substance...

Embodiment 2

[0030] The method technological process of present embodiment reclaiming benzene and toluene is the same as embodiment 1, and difference is that there is following difference in operating condition in each tower:

[0031] (1), the pre-rectification tower 3 is a packed tower, the operating pressure in the tower 3 is 0.1MPa (G), the tower top temperature is 107 ℃, and the reflux ratio is 1.05; the raw material mixture 10 is 2704.65kg / h, wherein n-pentane 2.8kg / h, cyclopentane 30.5kg / h, n-hexane 18.5kg / h, cyclohexane 13.75kg / h, n-heptane 4.0kg / h, methylcyclohexane 10.40kg / h, benzene 1830.50kg / h, toluene 550.60kg / h, dimethylcyclohexane 4.00kg / h, n-octane 0.80kg / h, ethylcyclohexane 2.5kg / h, carbon 8 aromatics 180.80kg / h, carbon 9 or more hydrocarbons 55.50kg / h;

[0032] (2), benzene-toluene separation tower 7 is a packed tower, the operating pressure is-0.05MPa(G), and the temperature at the bottom of the tower is 88°C.

[0033] The mixed solution 13 discharged from the bottom of ...

Embodiment 3

[0039] The method technological process of present embodiment reclaiming benzene and toluene is also identical with embodiment 1, and difference is that there is following difference in operating condition in each tower:

[0040] (1), the pre-rectification tower 3 is a packed tower, the operating pressure in the tower 3 is 0.5MPa (G), the tower top temperature is 157 ℃, and the reflux ratio is 1.45; the raw material mixture 15 is 2961.65kg / h, wherein n-pentane 2.5kg / h, cyclopentane 55.05kg / h, n-hexane 18.00kg / h, cyclohexane 15.15kg / h, n-heptane 4.8kg / h, methylcyclohexane 9.00kg / h, benzene 2300.90kg / h, toluene 360.50kg / h, dimethylcyclohexane 4.00kg / h, n-octane 0.55kg / h, ethylcyclohexane 2.7kg / h, carbon 8 aromatics 150.50kg / h, carbon 9 or more hydrocarbons 38kg / h;

[0041] (2), benzylbenzene separation tower 7 is a plate tower, the operating pressure is 0.10MPa (G), the temperature at the bottom of the tower is 138 ° C, and the reflux ratio is 1.3.

[0042] Pre-rectification ...

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Abstract

The invention discloses a recycling method of benzene and toluene, which comprises the following steps: prerectifying; extracting; separating benzene and toluene; pressurizing the prerectifying tower under lower pressure and temperature; adopting stream of tower top as heat source of reboiler of benzene and toluene.

Description

technical field [0001] The present invention relates to the method for reclaiming aromatics from the mixture containing aromatics and non-aromatics, in particular to a method for utilizing an extractant (such as N-formylmorpholine, N-acetylmorpholine, etc.), extracting and rectifying recovery of benzene and Toluene method. Background technique [0002] Using extractive distillation technology to recover aromatics from mixtures containing aromatics and non-aromatics has been widely used in petrochemical, coking crude benzene hydrotreating and other processes (such as German patents 1568940, 2040025, 4586986, etc.). The general process is: the raw material mixture is separated into light components and heavy components by pre-rectification, and the heavy components are discharged from the system for further treatment; the light components enter the extractive distillation tower, and N-formylmorpholine is used as the extraction agent. Carry out extraction and rectification sep...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07C7/04C07C7/08C07C15/04C07C15/06
Inventor 林必华汤洪黄维柱胡文励胡玲蹇守华
Owner SOUTHWEST RES & DESIGN INST OF CHEM IND
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