阅读说明：本技术 一种利用富碳天然气进行羰基合成的方法 (Method for carbonyl synthesis by using carbon-rich natural gas ) 是由 吴青 鹿晓斌 曲顺利 杨璐 郭雷 王江涛 贺同强 于 2020-06-22 设计创作，主要内容包括：本发明提供一种利用富碳天然气进行羰基合成的方法,所述方法包括以下步骤：(1)将净化后的所述富碳天然气进行预热,之后进行重整反应得到合成气；(2)所述合成气净化后与不饱和化合物进行羰基合成反应,产物进行分离提纯后得到比原料不饱和化合物多一个碳的醛。所述方法不但解决了富碳天然气的资源化利用的问题,还满足了羰基合成对合成气的需求,提高过程能效碳效,并兼顾高效减排,进而实现富碳天然气特色资源的清洁转化和高效利用。(The invention provides a method for carbonyl synthesis by using carbon-rich natural gas, which comprises the following steps: (1) preheating the purified carbon-rich natural gas, and then carrying out reforming reaction to obtain synthesis gas; (2) and (3) carrying out carbonyl synthesis reaction on the purified synthesis gas and an unsaturated compound, and separating and purifying a product to obtain the aldehyde with one more carbon than the unsaturated compound of the raw material. The method solves the problem of resource utilization of the carbon-rich natural gas, meets the requirement of carbonyl synthesis on the synthesis gas, improves the process energy efficiency and carbon efficiency, gives consideration to high-efficiency emission reduction, and further realizes clean conversion and high-efficiency utilization of the characteristic resources of the carbon-rich natural gas.)

1. A method for oxo synthesis using carbon-rich natural gas, the method comprising the steps of:

(1) preheating the purified carbon-rich natural gas, and then carrying out reforming reaction to obtain synthesis gas;

(2) and (3) carrying out carbonyl synthesis reaction on the purified synthesis gas and an unsaturated compound, and separating and purifying a product to obtain the aldehyde with one more carbon than the unsaturated compound of the raw material.

2. The method of claim 1, wherein the carbon-rich natural gas is subjected to the purification in a natural gas purification unit.

3. The method according to claim 1 or 2, wherein the pressure of the purified carbon-rich natural gas is 1.5-3.0 Mpag, the temperature is 10-50 ℃, and the CO is in the range of₂The molar content is 20-60%, and the content of the low-carbon alkane is less than 3%;

preferably, the lower alkane comprises C₂H₆And C₃H₈。

4. The process according to any one of claims 1 to 3, characterized in that the preheating is carried out in a heat exchange unit;

preferably, the heat exchange unit is a dividing wall type heat exchanger.

5. The process of any one of claims 1 to 4, wherein the reforming reaction is carried out at a pressure of 1.5 to 3.0 Mpag;

preferably, the temperature of the reforming reaction is 850-1300 ℃.

6. The method according to any one of claims 1 to 5, wherein the reforming reaction is carried out in a reformer;

preferably, the reformer comprises a self-heating reformer and/or a heat exchange tube reformer.

7. The process according to any one of claims 1 to 6, characterized in that the oxo reaction is carried out under the action of a catalyst;

preferably, the catalyst comprises a rhodium-based catalyst.

8. The method according to any one of claims 1 to 7, wherein the temperature of the oxo reaction is 70 to 90 ℃;

preferably, the pressure of the oxo reaction is 1.0-2.0 Mpag;

preferably, the unsaturated compound comprises an alkene or alkene derivative.

9. The method according to any one of claims 1 to 8, wherein the method of separation and purification comprises:

and after the product of the oxo reaction is separated by the separation tower, returning alkane in the overhead fraction to perform reforming reaction, returning unsaturated compounds in the overhead fraction to perform reforming reaction and/or returning to perform the oxo reaction, wherein the bottom fraction is aldehyde with one carbon more than the unsaturated compounds of the raw materials.

10. Method according to any of claims 1-8, characterized in that the method comprises the steps of:

(1) preheating the carbon-rich natural gas purified in the natural gas purification unit in a heat exchange unit, and then carrying out reforming reaction in a converter to obtain synthesis gas, wherein the pressure of the reforming reaction is 1.5-3.0 Mpag, and the temperature of the reforming reaction is 850-1300 ℃;

wherein the pressure of the purified carbon-rich natural gas is 1.5-3.0 Mpag, the temperature is 15-30 ℃, and CO is₂The molar content is 20-60%, and the content of the low-carbon alkane is less than 3%;

(2) the synthesis gas is purified and then is subjected to oxo reaction with an unsaturated compound under the catalysis of a rhodium catalyst, the temperature of the oxo reaction is 70-90 ℃, the pressure is 1.0-2.0 Mpag, and the product is separated and purified to obtain aldehyde with one more carbon than the unsaturated compound of the raw material;

wherein, the method for separating and purifying comprises the following steps: and after the product of the oxo reaction is separated by the separation tower, returning alkane in the overhead fraction to perform reforming reaction, returning unsaturated compounds in the overhead fraction to perform reforming reaction and/or returning to perform the oxo reaction, wherein the bottom fraction is aldehyde with one carbon more than the unsaturated compounds of the raw materials.

Technical Field

The invention belongs to the technical field of comprehensive utilization of carbon-rich natural gas, and relates to a method for carbonyl synthesis by using carbon-rich natural gas.

Background

Oxo refers to the process of producing fatty aldehydes having one more carbon atom than the original olefin by the reaction of carbon monoxide and hydrogen with olefins in the presence of a catalyst, and is also called "hydroformylation (reaction)" or "hydroformylation reaction". Oxo plays an important role in the chemical industry, and numerous chemicals can be produced by oxo processes. The carbon monoxide and hydrogen required for oxo are collectively referred to as "syngas", and the composition of the syngas, H₂CO is about 1: 1.

Currently, synthesis gas is mostly produced by steam reforming of methane or coal, H₂CO is about 3:1, and reverse water gas shift of steam reformed gas or excess H is required for the oxo process₂And (4) separating. If methane and carbon dioxide are reformed to produce synthesis gas, theoretically H₂The CO is 1:1, can be directly used for oxo synthesis, is simpler than a steam reforming process, and saves energy and reduces consumption.

In addition, as a natural gas with unique characteristics, the carbon-rich natural gas is extremely efficient, environment-friendly and energy-saving in comprehensive utilization technology development. From south China seaSea gas fields, for example, have a composition of natural gas that is very different from the composition of other regions of the inland and are characterized by a high concentration of CO in the natural gas₂. Many detection data at home and abroad indicate that the CO of the typical high carbon dioxide gas field of the south China and the China sea₂In the content of>20 percent. Natural gas CO based on the transportation requirements of commercial natural gas₂The content of CO in the liquefied natural gas is not more than 3 percent₂The content of CO in the natural gas produced from the south-sea area gas field is not more than 0.2 percent₂The contents are generally high and therefore partial CO removal at sea is necessary₂Can be further used. Separation of CO from Natural gas₂The process inevitably increases the energy consumption, and also causes the loss of the natural gas, and related researches show that the loss rate of the natural gas is between 2.5 and 7 percent in the process of decarbonizing the natural gas. In addition, CO is removed from natural gas₂If directly discharged into the atmosphere, serious greenhouse gas influence is caused to the environment.

Disclosure of Invention

Aiming at the technical problems in the prior art, the invention aims to provide a method for carrying out oxo synthesis by using carbon-rich natural gas, which utilizes the characteristic that the carbon-rich natural gas has high carbon dioxide content, changes disadvantages into benefits and changes waste into valuable, directly prepares synthetic gas for oxo synthesis by reforming carbon dioxide, couples the preparation of the synthetic gas with oxo synthesis reaction, solves the problem of resource utilization of the carbon-rich natural gas, also meets the requirements of the oxo synthesis on the synthetic gas, simplifies the process flow, reduces the emission of greenhouse gas, and realizes energy conservation and consumption reduction in chemical production.

In order to achieve the purpose, the invention adopts the following technical scheme:

the invention provides a method for carbonyl synthesis by using carbon-rich natural gas, which comprises the following steps:

(1) preheating the purified carbon-rich natural gas, and then carrying out reforming reaction to obtain synthesis gas;

(2) and (3) carrying out carbonyl synthesis reaction on the purified synthesis gas and an unsaturated compound, and separating and purifying a product to obtain the aldehyde with one more carbon than the unsaturated compound of the raw material.

As a preferred embodiment of the present invention, the carbon-rich natural gas is subjected to the purification in a natural gas purification unit.

In the invention, the natural gas purification unit mainly carries out purification treatment such as dehydration, heavy hydrocarbon separation, desulfurization, demercuration and the like on the carbon-rich natural gas.

According to the preferable technical scheme, the pressure of the purified carbon-rich natural gas is 1.5-3.0 Mpag, the temperature is 10-50 ℃, and CO is₂The molar content is 20-60%, and the content of the low-carbon alkane is less than 3%.

Wherein the pressure of the carbon-rich natural gas can be 1.6Mpag, 1.8Mpag, 2.0Mpag, 2.2Mpag, 2.5Mpag or 2.8Mpag, etc., the temperature can be 15 ℃, 20 ℃, 25 ℃, 30 ℃, 35 ℃, 40 ℃ or 45 ℃, etc., CO₂The molar content may be 25%, 30%, 35%, 40%, 45%, 50% or 55%, etc., and the lower alkane content may be 0.5%, 1%, 1.5%, 2% or 2.5%, etc., but the content is not limited to the recited values, and other values not recited in the above numerical ranges are also applicable.

Preferably, the lower alkane comprises C₂H₆And C₃H₈。

As a preferred technical solution of the present invention, the preheating is performed in a heat exchange unit.

Preferably, the heat exchange unit is a dividing wall type heat exchanger.

In the invention, the carbon-rich natural gas is preheated and then is heated by a second heat exchange unit, and the second heat exchange unit is a dividing wall type heat exchanger.

In a preferred embodiment of the present invention, the reforming reaction pressure is 1.5 to 3.0Mpag, such as 1.6Mpag, 1.8Mpag, 2.0Mpag, 2.2Mpag, 2.5Mpag, or 2.8Mpag, but the reforming reaction pressure is not limited to the above-mentioned values, and other values not shown in the above-mentioned range are also applicable.

Preferably, the temperature of the reforming reaction is 850 to 1300 ℃, such as 900 ℃, 950 ℃, 1000 ℃, 1050 ℃, 1100 ℃, 1150 ℃, 1200 ℃ or 1250 ℃, but not limited to the recited values, and other values not recited in the range of the values are also applicable.

In a preferred embodiment of the present invention, the reforming reaction is carried out in a reformer.

Preferably, the reformer comprises a self-heating reformer and/or a heat exchange tube reformer.

In the invention, the reforming reaction is carried out to obtain the carbon-rich natural gas, and the carbon-rich natural gas is reacted with O in the converter₂(or air) to carry out reforming reaction and combustion reaction, the reaction system is complex, and the existing reactions mainly comprise:

CH₄+2O₂＝CO₂+2H₂O

2C₂H₆+7O₂＝4CO₂+6H₂O

C₃H₈+5O₂＝3CO₂+4H₂O

2C_nH_2n+3nO₂＝2nCO₂+2nH₂O

CH₄+CO₂＝2CO+2H₂

CH₄+H₂O＝CO+3H₂

CO+H₂O＝CO₂+H₂

in a preferred embodiment of the present invention, the oxo reaction is carried out in the presence of a catalyst.

Preferably, the catalyst comprises a rhodium-based catalyst.

In the present invention, the synthesis gas is subjected to a purification treatment prior to the oxo reaction, said purification treatment serving to remove impurities such as sulfur and mercury which may cause catalyst deactivation.

In a preferred embodiment of the present invention, the temperature of the oxo reaction is 70 to 90 ℃, for example, 72 ℃, 75 ℃, 78 ℃, 80 ℃, 82 ℃, 85 ℃ or 88 ℃, but the temperature is not limited to the above-mentioned values, and other values not shown in the above-mentioned range are also applicable.

Preferably, the pressure of the oxo reaction is 1.0 to 2.0Mpag, such as 1.1Mpag, 1.2Mpag, 1.3Mpag, 1.4Mpag, 1.5Mpag, 1.6Mpag, 1.7Mpag, 1.8Mpag or 1.9Mpag, but not limited to the recited values, and other values not recited in this range are equally applicable.

Preferably, the unsaturated compound comprises an alkene or alkene derivative.

In the present invention, the oxo reaction is carried out by hydroformylation of raw material olefin or olefin derivative and synthesis gas with hydrogen-carbon ratio of about 1 in the presence of rhodium catalyst to obtain aldehyde with one more carbon than the raw material olefin

As a preferred technical scheme of the invention, the separation and purification method comprises the following steps:

and after the product of the oxo reaction is separated by the separation tower, returning alkane in the overhead fraction to perform reforming reaction, returning unsaturated compounds in the overhead fraction to perform reforming reaction and/or returning to perform the oxo reaction, wherein the bottom fraction is aldehyde with one carbon more than the unsaturated compounds of the raw materials.

As a preferred embodiment of the present invention, the method for synthesizing carbonyl by using carbon-rich natural gas comprises the following steps:

(1) preheating the carbon-rich natural gas purified in the natural gas purification unit in a heat exchange unit, and then carrying out reforming reaction in a converter to obtain synthesis gas, wherein the pressure of the reforming reaction is 1.5-3.0 Mpag, and the temperature of the reforming reaction is 850-1300 ℃;

wherein the pressure of the purified carbon-rich natural gas is 1.5-3.0 Mpag, the temperature is 15-30 ℃, and CO is₂The molar content is 20-60%, and the content of the low-carbon alkane is less than 3%;

(2) the synthesis gas is purified and then is subjected to oxo reaction with an unsaturated compound under the catalysis of a rhodium catalyst, the temperature of the oxo reaction is 70-90 ℃, the pressure is 1.0-2.0 Mpag, and the product is separated and purified to obtain aldehyde with one more carbon than the unsaturated compound of the raw material;

wherein, the method for separating and purifying comprises the following steps: and after the product of the oxo reaction is separated by the separation tower, returning alkane in the overhead fraction to perform reforming reaction, returning unsaturated compounds in the overhead fraction to perform reforming reaction and/or returning to perform the oxo reaction, wherein the bottom fraction is aldehyde with one carbon more than the unsaturated compounds of the raw materials.

Compared with the prior art, the invention at least has the following beneficial effects:

(1) the invention provides a method for carbonyl synthesis by using carbon-rich natural gas, which avoids the decarbonization link of the carbon-rich natural gas, avoids the loss of the natural gas, saves energy and reduces consumption;

(2) the invention provides a method for carbonyl synthesis by using carbon-rich natural gas, which realizes high CO content₂The low-carbon alkane with the content is utilized in a high-value manner, and the carbon emission reduction effect is obvious;

(3) the invention provides a method for carrying out oxo synthesis by using carbon-rich natural gas, which utilizes methane-carbon dioxide reforming to prepare synthesis gas with a hydrogen-carbon ratio of about 1, can be directly used for oxo synthesis, and reduces hydrogen separation compared with the synthesis gas obtained by methane steam reforming;

(4) the invention provides a method for carbonyl synthesis by using carbon-rich natural gas, which introduces oxygen (or air) to perform oxidation reaction with low-carbon alkane or olefin to release heat to provide heat for a converter;

(5) the invention provides a method for carrying out oxo synthesis by using carbon-rich natural gas, which returns oxo synthesis tail gas to a system and reduces tail gas emission.

Drawings

FIG. 1 is a schematic flow diagram of a process for oxo synthesis using carbon-rich natural gas according to example 1 of the present invention;

FIG. 2 is a schematic flow diagram of the oxo process using carbon-rich natural gas in example 2 of the present invention.

The present invention is described in further detail below. The following examples are merely illustrative of the present invention and do not represent or limit the scope of the claims, which are defined by the claims.

Detailed Description

The technical scheme of the invention is further explained by the specific implementation mode in combination with the attached drawings.

To better illustrate the invention and to facilitate the understanding of the technical solutions thereof, typical but non-limiting examples of the invention are as follows: