TW201443220A - Process for producing synthesis gas for conversion into products - Google Patents

Abstract

The invention relates to a process for producing synthesis gas for conversion into products, in particular for synthesis gas liquefaction. In order to develop the process further in such a way that an increase in synthesis gas production is achieved, the following process steps are carried out: (a) introduction of a carbon-containing fuel (1) into a reactor (6) in which the fuel (1) is reacted to give a crude synthesis gas (2); (b) purification of the crude synthesis gas (2), with the purified crude synthesis gas (2) being introduced, together with methane formed, as main synthesis gas stream (3) into synthesis gas conversion in which an offgas (4) is also produced; (c) conversion of the offgas (4) produced into a pure synthesis gas (5) and introduction of the pure synthesis gas (5) into the main synthesis gas stream (3).

Description

Method for producing syngas for conversion to products

This invention relates to a process for the production of synthesis gas for conversion to a product, especially for the liquefaction of synthesis gas.

Methods of the type mentioned at the outset are known in the prior art.

For this purpose, a carbonaceous fuel, such as biomass or coal, is introduced into the reactor where it is at a high temperature, preferably at a temperature between 800 ° C and 1200 ° C or higher, by means of gas For example, by entrained flow gasification, fluidized bed gasification or other gasification processes (eg, fixed bed gasification, etc.), carbon-containing fuels are reacted with air or oxygen or oxygen-enriched air, and with water vapor and carbon dioxide to produce A crude syngas consisting essentially of hydrogen, carbon dioxide and carbon monoxide.

In a further step of the method of the type mentioned at the outset, the raw syngas produced is purified by filtration and chemical/physical methods to remove material (e.g., part of chlorine, sulfur, carbon dioxide and dust) from the crude syngas. The purified crude syngas is then introduced into the synthesis gas to produce a liquid end product, for example, according to Fischer-Tropsch-Synthese or methanol synthesis.

Synthesis gas conversion technology (e.g., synthesis gas liquefaction) typically require high quality gas, e.g., pure CO ₂ and H of the gas. However, this leads to the problem that the crude syngas from the method of the type mentioned at the outset always also contains a methane fraction, which by experience has a methane content of from about 4% to 10%. This means that almost complete production of pure syngas (for example, a gas consisting of pure CO and H ₂ ) cannot be ensured, which in turn leads to the non-substantial chemical energy being continuously stored in methane and higher hydrocarbons. As a result, the overall process of gas liquefaction The efficiency is impaired.

It is an object of the present invention to further develop a method of the type mentioned at the outset to achieve an increase in syngas production.

In the type of process mentioned at the outset, this object is achieved according to the invention by converting the offgas produced during the conversion to pure syngas and introducing it into the purified main syngas stream.

Advantageous embodiments of the invention are defined in the dependents.

The key idea of the present invention is to incorporate an additional loop containing converted pure syngas into the process, i.e., to convert the off-gas produced during the liquefaction process in the syngas liquefaction system to pure syngas, and to produce Pure syngas is introduced correspondingly to the main syngas stream. Since pure syngas is additionally introduced into the main syngas stream, a high proportion of purified syngas is advantageously passed into the syngas liquefaction unit via the main syngas stream, which in turn leads to an increase in the production of the desired liquid product and thus also to the overall process. Higher efficiency.

Since the production of the exhaust gas can be continuously related to the method (for example, liquefaction of syngas), the produced exhaust gas is converted into pure syngas and the introduction of the pure syngas into the main syngas stream is preferably performed more than once, that is, ideally In this case, until almost all of the exhaust gas has been converted. For the conversion of the exhaust gas, it is advantageous to provide a reformer, in particular an autothermal reformer or a catalytic reformer.

An advantageous embodiment of the invention proposes that the recombiner is installed downstream of the syngas conversion unit.

1‧‧‧carbon fuel

2‧‧‧ coarse syngas

3‧‧‧Main syngas stream

4‧‧‧Exhaust

5‧‧‧ pure syngas

6‧‧‧Reactor

7‧‧‧Synthesis gas purification unit

8‧‧‧Syngas conversion unit

9‧‧‧Reorganizer

10‧‧‧ final product

Further advantages, features and details of the invention are obtained from the following description and the drawings.

Figure 1 is a flow chart showing the flow of a program for carrying out the method of the present invention.

The apparatus for carrying out the process of the invention consists essentially of a plant component reactor 6, a syngas purification unit 7, a syngas conversion unit 8 and a reformer 9, wherein the recombiner 9 is configured as an autothermal reformer. The syngas conversion unit 8 is disposed between the syngas purification unit 7 and the recombiner 9.

The method begins by introducing a carbonaceous fuel 1, such as biomass, gas, liquid or coal, into the reactor 6, in which the carbonaceous fuel 1 is combined with air or oxygen, and with water vapor. The carbon dioxide reacts to produce a crude syngas 2 . The reaction is carried out by gasification (for example, entrained flow gasification, fixed bed gasification or fluidized bed gasification) and is carried out at a high temperature, wherein the high temperature can be in the range of 800 ° C to 1200 ° C and higher.

In the next process step, the raw synthesis gas 2 produced essentially consisting of hydrogen, carbon dioxide and carbon monoxide, together with the methane produced by gasification in the reactor 6, is introduced into the synthesis gas purification unit 7 for use therein. purification. Purification of the crude syngas 2 in the syngas purification unit 7 is carried out in a conventional manner, for example, by filtration and chemical/physical methods. In particular, during the purification process, chlorine, sulfur, carbon dioxide and dust fractions are removed from the crude syngas 2 to form a purified main syngas stream 3, however, the purified main syngas stream 3 still contains additional methane fraction .

As shown in Figure 1, the next method step provides for introduction of the main syngas stream 3 to the syngas conversion unit 8.

In the syngas conversion unit 8, the syngas is liquefied in a conventional manner, for example according to Fischer-Tropsch synthesis or methanol synthesis, to produce the final product 10. According to the invention, the exhaust gas 4 (for example, carbon monoxide, hydrogen, methane and higher hydrocarbons) formed in the liquefaction of the synthesis gas is first introduced into the reformer 9 via an additional circuit for subsequent conversion to the pure Syngas 5, wherein the reformer 9 is installed downstream of the syngas conversion unit 8, and in the embodiment shown in Fig. 1 is an autothermal reformer. The pure syngas 5 is introduced successively into the main syngas stream 3 and supplied to the syngas conversion unit 8.

The described embodiments of the invention may be modified as appropriate in various ways without departing from the basic scope of the invention. For example, a gasification technique other than entrained flow gasification or fluidized bed gasification can also be used in the reactor 6. Techniques other than filtration and chemical reactions can also be used for purification in the syngas purification unit 7. The syngas can also pass through this additional installed circuit multiple times.

1‧‧‧carbon fuel

2‧‧‧ coarse syngas

3‧‧‧Main syngas stream

4‧‧‧Exhaust

5‧‧‧ pure syngas

6‧‧‧Reactor

7‧‧‧Synthesis gas purification unit

8‧‧‧Syngas conversion unit

9‧‧‧Reorganizer

10‧‧‧ final product

Claims (7)

A process for the production of synthesis gas for conversion to other products, in particular for the liquefaction of synthesis gas, the process comprising the steps of: a) introducing a carbonaceous fuel (1) into a reactor (6), In the reactor (6), the carbonaceous fuel (1) is at a high temperature, preferably at 800 ° C to 1200 ° C or higher, with air or oxygen or oxygen-enriched air, and with water vapor and CO _{2 .} The reaction produces a crude syngas (2) consisting essentially of hydrogen, carbon dioxide and carbon monoxide and additionally having a methane fraction, b) purifying the crude syngas (2), and purifying the crude syngas ( 2) together with the formed methane as the main synthesis gas stream (3) introduced into the synthesis gas conversion, in which the exhaust gas (4) is also produced; and c) the produced exhaust gas (4) is converted into pure synthesis gas (5) And introducing the pure syngas (5) to the main syngas stream (3). The method of claim 1, wherein the exhaust gas (4) is supplied to a reformer (9). The method of claim 2, wherein the recombiner (9) is an autothermal recombiner or a catalytic recombiner. The method of claim 2 or 3, wherein the recombiner (9) is installed downstream of a syngas conversion unit (8). The method of claim 4, wherein the syngas conversion unit (8) is disposed between a syngas purification unit (7) and the recombiner (9). The method of claim 4 or 5, wherein the syngas conversion unit (8) is installed downstream of the syngas purification unit (7). The method of any of the preceding claims, wherein the method step c) is performed more than once.