CN102180760B - Method for preparing benzene-free heptane solvent - Google Patents

Abstract

The invention discloses a method for preparing a benzene-heptane-free solvent, which comprises the following steps: (1) removing light components: cutting oil after hexane extraction enters a light removal tower, and removes light components from the top of the tower, The effluent from the tower is the crude heptane after removing the light components; (2) Removing the heavy components: the crude heptane after the heavy components are removed in step (1) enters the heavy removal tower, and is collected from the top of the tower to remove The crude heptane of the heavy component, the liquid discharged from the tower kettle is a mixed liquid containing the medium and heavy component; (3) Catalytic hydrogenation: the crude heptane after removing the heavy component in step (2) is catalytically added to the hydrogenation reactor The hydrogen reaction converts aromatics into alkanes, and the gas separated from the reaction liquid by the separation tank enters the condenser for condensation, and the condensed liquid is a benzene-heptane-free solvent. The invention has a simple process, can be industrialized, and has a heptane yield of more than 80%, which fills the gap in domestic (environmental protection) industrial scale production of benzene-heptane-free solvents; and produces better economic and social benefits.

Description

A kind of method for preparing phenylheptane solvent

technical field

The invention relates to a method for preparing a benzene-heptane-free solvent, which belongs to the field of chemical production.

Background technique

Series (environmentally friendly) n-heptane solvent, which is an extremely widely used industrial solvent. At present, my country can only produce a small amount of aromatic-containing heptane solvents. With the continuous development of petrochemical, pharmaceutical and food industries, some properties of this industrial-grade solvent can no longer meet the needs. The development of series (different content) environmental protection green benzene-free It is an urgent task for our company to increase product varieties and improve product grades for n-heptane solvents. This is also an effective way to improve the competitiveness of enterprises under the market economy.

Contents of the invention

The technical problem to be solved by the present invention is to overcome the existing defects and provide a method for preparing a benzene-heptane solvent with simple process, industrial scale production, environmental protection and benzene-free.

In order to solve the problems of the technologies described above, the present invention provides the following technical solutions:

A method for preparing solvent-free phenylheptane, using cutting oil after hexane extraction as raw material, comprising the steps of:

(1) Removal of light components: the cut oil after hexane extraction enters the light removal tower, maintains the temperature of the kettle at 104±2°C, controls the temperature at the top of the tower at 98±2°C, and removes the light components from the top of the tower , part of the light component is sent to the storage tank after being condensed by the condenser, and part of it is sent to the top of the tower to reflux, and the effluent from the tower kettle is crude heptane after removing the light component;

(2) Removal of heavy components: the crude heptane after removal of heavy components in step (1) enters the heavy removal tower, the temperature of the tower bottom is controlled at 132±2°C, and the temperature of the top of the tower is 120±2°C. The crude heptane that removes heavy components is sent to the top of the heavy removal tower as reflux after being condensed by the condenser, and the liquid discharged from the tower kettle is a mixed liquid containing medium and heavy components;

(3) Catalytic hydrogenation: The crude heptane after removal of heavy components in step (2) undergoes catalytic hydrogenation reaction in a hydrogenation reactor to convert aromatics into alkanes, and the gas separated from the reaction liquid by the separation tank enters the condenser Condensation is carried out, and the condensed liquid is a phenylheptane-free solvent.

The catalytic hydrogenation reaction in step (3) uses NCG catalyst as the catalyst.

Further, in step (1) and step (2), the temperature of the tower still of the light removal tower is adjusted through the tower still reboiler respectively.

Further, the cut oil extracted with hexane in step (1) is preheated with the effluent from the delightening tower and then sent to the dehydrogenation tower to remove light components.

Further, in step (2), the heavy weight removed by the deweighting tower is sent to the hexane production workshop as the raw material for hexane production.

The beneficial effects of the present invention are as follows:

The n-heptane content in the cut oil after hexane extraction is pretreated by the initial distillation tower is more than 25%, and the light components in the components are removed at the same time; the material is further processed by the rectification tower, and the top of the tower is obtained More than 40% is heptane; the material is separated by rectification to obtain n-heptane with a mass fraction of 40%-90%, and the mixed liquid containing medium and heavy components flows out from the tower; after the aromatics are converted into alkanes through a hydrogenation reactor , to obtain a series of benzene-heptane-free solvent products with a mass fraction of 40-90%. The process of the invention is simple and can be produced industrially. ; Generate better economic and social benefits.

Description of drawings

The accompanying drawings are used to provide a further understanding of the present invention, and constitute a part of the description, and are used together with the embodiments of the present invention to explain the present invention, and do not constitute a limitation to the present invention. In the attached picture:

Fig. 1, Fig. 2 are the process flow diagrams of the method for preparing no-phenylheptane solvent of the present invention.

Detailed ways

The preferred embodiments of the present invention will be described below in conjunction with the accompanying drawings. It should be understood that the preferred embodiments described here are only used to illustrate and explain the present invention, and are not intended to limit the present invention.

Example 1

The method for preparing benzene-free heptane solvent described in the present invention uses the cutting oil after hexane extraction as a raw material when producing heptane, adopts two towers for rectification, one tower removes light components, and the second tower removes heavy components, Obtain 80% crude heptane product (containing about 1% toluene by mass fraction), and then use liquid-phase hydrogenation to remove toluene to the crude heptane containing about 1% toluene under the action of catalyst to obtain 80% (mass fraction) of refined heptane products.

The concrete technological process is as follows: as shown in Figure 1 and Figure 2, the lines of label A, B, C, D in Figure 1 are connected with the lines of label A, B, C, D' in Figure 2 in one-to-one correspondence respectively, and hexane After the extracted cutting oil is preheated from the raw material tanks 11 and 12 through the heat exchanger 3 and the tower still liquid flowing out from the bottom of the light removal tower 4, it is pumped into the light removal tower 4 by the feed pumps 801 and 802 to remove the low boiling point. The low-boiling light components distilled from the top of the tower enter the condensers 61 and 62 for condensation, the uncondensed tail gas is discharged at high altitude, the condensed light components enter the reflux tank 7, and a part of the light components pass through the pump 806 Pumped into the storage tank 9, a part of the light component is sent back to the top reflux of the light removal tower 4 by the reflux pump 805. The temperature of the bottom of the light removal tower 4 is controlled at 104±2°C, and the temperature at the top of the tower is controlled at 98±2°C. The tower bottom reboiler 5 that is arranged at the tower bottom of the light removal tower 4 adjusts the temperature of the tower kettle, and the tower kettle liquid is pumped to the weight removal tower 14 by pumps 803 and 804 to remove heavy components, and the temperature of the weight removal tower 14 is controlled at 132 ± 2°C, the temperature at the top of the tower is 120±2°C, the temperature of the kettle is adjusted through the bottom reboiler 13 installed at the bottom of the tower, and the distillate at the top of the tower is cooled to 40°C and 20°C by condensers 15 and 16, and flows into the reflux tank respectively In 24, a part of the crude heptane is sent back to the top of the weight removal tower 14 by pump 812 for reflux, and a part of the crude heptane product is pumped to the crude heptane tanks 251, 252, 253 by the pump 813, and the still liquid passes through the tower still heat exchanger After 10 is cooled to 50°C, a part is pumped into the tower bottom reboiler 5 through the pump 807 to adjust the temperature in the tower, and the other part is sent into the residual liquid tank 18 through the pump 808, and is transported to Hexane production workshop as petroleum ether product.

The crude heptane stored in the crude heptane tanks 251, 252, and 253 after being rectified by the light removal tower 4 and the weight removal tower 14 (the crude heptane contains 1.2% aromatics by mass fraction) is fed by the feed pump 809 The pump is sent to the preheater 17, preheated to 140~150 degrees, the hydrogen is decompressed from 2.8~3Mpa in the hexane workshop to 0.8~0.9Mpa, and then the flow rate is adjusted to 11.2NM3, and then enters the mixer 26 together with the crude heptane After fully mixed in the crude heptane, it enters the hydrogenation reactor 19, and under the action of the CNG catalyst, the aromatics in the crude heptane are hydrogenated and converted into alkanes. After the reaction liquid enters the vapor-liquid separation tank 20 for separation, the liquid enters the storage tank after being cooled by the cooler, and the gas enters the cooler after passing through the tank top condenser, and the condensed liquid solvent oil has a content of 80% (mass fraction ) to the refined heptane product tank, and the non-condensable gas enters the flare header.

Finally, it should be noted that: the above is only a preferred embodiment of the present invention, and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, for those skilled in the art, it still The technical solutions recorded in the foregoing embodiments may be modified, or some technical features thereof may be equivalently replaced. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims (5)

1. prepare a method for solvent-free phenylheptane, it is characterized in that, take the cutting oil after hexane extraction as raw material, comprise the steps: (1) Removal of light components: the cut oil after hexane extraction enters the light removal tower, maintains the temperature of the kettle at 104±2°C, controls the temperature at the top of the tower at 98±2°C, and removes the light components from the top of the tower , part of the light component is sent to the storage tank after being condensed by the condenser, and part of it is sent to the top of the tower for reflux, and the effluent from the tower kettle is the crude heptane after removing the light component; (2) Removal of heavy components: the crude heptane after removal of light components in step (1) enters the weight removal tower, the temperature of the tower bottom is controlled at 132±2°C, and the temperature of the top of the tower is 120±2°C, collected from the top of the tower The crude heptane from which heavy components have been removed is condensed by a condenser and partly sent to the top of the weight removal tower as reflux, and the liquid discharged from the tower kettle is a mixed liquid containing medium and heavy components; (3) Catalytic hydrogenation: The crude heptane after removal of heavy components in step (2) is subjected to a catalytic hydrogenation reaction in a hydrogenation reactor to convert aromatics into alkanes, and the gas separated from the reaction liquid by the separation tank enters the condenser for further processing. Condensate, and the condensed liquid is a benzene-heptane-free solvent. 2. the method for preparing no-phenylheptane solvent according to claim 1, is characterized in that, catalytic hydrogenation reaction adopts NCG catalyst as catalyzer in step (3). 3. the method for preparing benzene-heptane-free solvent according to claim 1, is characterized in that, in step (1), step (2), adjust the tower still of light removal tower or heavy removal tower by tower still reboiler respectively temperature. 4. the method for preparing benzene-heptane-free solvent according to claim 1 is characterized in that, the cutting oil after the extraction of raw material hexane in step (1) is sent to The light removal tower removes light components. 5. The method for preparing benzene-heptane-free solvent according to claim 1, characterized in that, in step (2), the heavy fraction removed by the weight removal tower is sent to the hexane production workshop as the raw material for hexane production.

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