CN105668517A - Method for preparing synthetic gas from high temperature hydrocarbon-containing gas - Google Patents

Abstract

The invention relates to a method for preparing synthesis gas from high-temperature hydrocarbon-containing gas. The method mainly consists of three parts: a process burner, a high-temperature hydrocarbon-containing gas inlet and a reformer. Through the non-catalytic partial oxidation reaction process in the reformer, the high-temperature Methane, tar, benzene, phenol, etc. in the hydrocarbon gas are further converted into CO and _H2 -based synthesis gas. High-temperature hydrocarbon-containing gas has a wide range of sources, which can be gas phase products of pyrolysis or fixed-bed gasification of garbage, biomass, lignite, bituminous coal, etc. The synthesis gas produced by this method can be used for hydrogen production, synthetic ammonia, methanol, ethylene glycol, FT Synthesis and other processes, the use is extremely wide. The method is environmentally friendly, and the waste water in the synthesis gas washing process does not contain organic matters; the conversion rate of the high-temperature hydrocarbon-containing gas can reach more than 99 percent; the process flow and equipment structure are simple, and the investment is low.

Description

A method for preparing synthesis gas from high-temperature hydrocarbon-containing gas

technical field

The invention relates to a method for producing synthesis gas from hydrocarbon-containing materials, in particular to a method for preparing synthesis gas from high-temperature hydrocarbon-containing gas.

Background technique

During the years of operation of the fixed-bed gasifiers that use lignite and bituminous coal as raw materials, some engineering problems have not been effectively resolved. Such as:

(1) The problem of tar. The gas outlet temperature of the fixed-bed gasifier is low, which is low-temperature tar, especially containing fine powder, which is difficult to recycle; because the yield of tar is closely related to the characteristics of coal, the actual yield of tar for some coal types is very small. For example, a fixed-bed gasifier in a factory produces gas for coal-to-oil production, and tar is basically worthless. The special recovery cost is high and the operation is difficult.

(2) The problem of energy utilization. Considering the recovery of tar in the synthesis gas, a large amount of water is used to wash and cool the tar vapor into a liquid state first, which reduces the temperature of the synthesis gas; in addition, because the synthesis gas contains tar, it is easy to condense on the furnace tube of the waste heat boiler, and the tar and fine particles The powder condenses on the furnace tubes and affects the operation of the waste heat boiler. The existing Lurgi furnace process flow can only by-produce low-pressure steam.

(3) The problem of waste water. The most important problem of the existing fixed-bed gasifier is that it contains tar, benzene, phenols and other organic substances in large quantities, which makes wastewater treatment very difficult and requires huge investment.

(4) Further conversion of CH ₄ . The output synthesis gas methane content of the Lurgi furnace varies from 5 to 14% depending on the type of coal. Compared with other technologies, its calorific value is relatively high. It can be used as industrial gas or synthetic natural gas, but it is used for the synthesis of ammonia, methanol and other bulk chemicals For the production of products, it is necessary to use natural gas steam reforming process or partial oxidation process to further convert CH ₄ .

The overall gas composition of the gas phase products generated by pyrolysis or fixed bed gasification of garbage, biomass, etc. is similar to the outlet synthesis gas of the above coal fixed bed gasifier, which is an important technical problem that plagues the industry.

Contents of the invention

In view of the problems of the fixed bed gasification process mentioned above, the core is that the outlet temperature of the gasifier is low, and methane and tar are not completely converted, which brings problems to subsequent energy recovery, tar recovery, and wastewater treatment. The object of the invention is to propose a method for preparing synthesis gas from a high-temperature hydrocarbon-containing gas, and the technical concept is as follows:

(1) The conversion of tar and methane is completed by supplementing oxygen at the outlet of the fixed-bed gasifier to increase the conversion temperature. Polymer compounds such as tar are completely transformed at high temperature, so that the waste water does not contain organic matter, and the waste water is easy to treat and the amount is small. The high-temperature gas directly enters the reformer without cooling, and the energy is fully utilized. The high-temperature gas contains H2, H2O and other hydrogen-containing gases to promote the depyrolysis of tar.

(2) A waste heat boiler is installed at the outlet of the reformer to produce high-pressure steam by-product. After the synthesis gas is subjected to high temperature, the polymer organic matter in it is basically decomposed, and will not condense on the waste heat boiler tube, and the waste heat boiler can be operated for a long period of time.

The specific technical scheme is as follows:

A method for preparing synthesis gas from high-temperature hydrocarbon-containing gas, comprising the steps of:

The high-temperature hydrocarbon-containing gas (S1) is introduced into the reformer (2) through the inlet chamber (1) and the distribution hole (102) in sequence; at the same time, the oxidant is introduced into the reformer (2) through the process burner (3);

The high-temperature hydrocarbon-containing gas undergoes a non-catalytic partial oxidation reaction in the reformer (2) to generate synthesis gas mainly composed of CO+H ₂ ;

The high-temperature synthesis gas (S4) exiting the reformer (2) passes through the waste heat boiler (4) to by-produce high-pressure steam, and the cooled synthesis gas (S5) exiting the waste heat boiler (4) enters a downstream device;

The process burner (3) is a double channel, wherein the inner channel is an oxidant (S2) channel, and the outer channel is an auxiliary gasification agent (S3) channel;

The process burner (3) is connected to the inlet cavity (1) through the burner flange (301);

The inlet chamber (1) is connected with the reformer (2) through the inlet chamber flange (101).

The high-temperature hydrocarbon-containing gas is a gas-phase product of pyrolysis or fixed-bed gasification of garbage, biomass, lignite, bituminous coal, etc., and contains methane, tar, benzene, phenol and other organic substances.

The oxidizing agent is oxygen, air or oxygen-enriched air.

The medium of the auxiliary gasification agent channel of the process burner may be incombustible gas such as water vapor, CO ₂ , N ₂ , or liquid water.

The material of the lining to the fire surface of the reforming furnace (2) is a refractory brick.

The waste heat boiler (4) may be a water tube boiler or a fire tube boiler.

The working pressure of the reformer (2) is 0.1-12MPa; the temperature of the high-temperature hydrocarbon-containing gas (S1) is 300-800°C; the temperature of the high-temperature synthesis gas (S4) exiting the reformer (2) is 900-1700°C; the temperature of the cooled synthesis gas (S5) exiting the waste heat boiler (4) is 200-400°C.

The invention relates to a method for preparing synthesis gas from high-temperature hydrocarbon-containing gas, which further converts methane, tar, benzene, phenol, etc. in the high-temperature hydrocarbon-containing gas into CO and _H2 -based synthesis gas. The method is environmentally friendly, and the waste water in the synthesis gas washing process does not contain organic matter; the conversion rate of the high-temperature hydrocarbon-containing gas can reach more than 99 percent; the process flow and equipment structure are simple, and the investment cost is low.

Description of drawings

Figure 1 is a schematic process flow diagram of the method for producing synthesis gas in Example 1.

Symbol Description

1 entrance mouth; 101 entrance flange; 102 distribution holes; 2 reformer; 3 process burner;

301 burner flange; 4 waste heat boiler; S1 high temperature hydrocarbon-containing gas; S2 oxidant;

S3 auxiliary gasification agent; S4 high temperature syngas; S5 cooled syngas.

detailed description

The following examples are used to further illustrate the present invention, but the protection scope of the present invention is not limited to the examples. Other changes and modifications made by those skilled in the art without departing from the spirit and protection scope of the present invention are still included in the protection scope of the present invention.

Example 1

Referring to Figure 1, the high-temperature hydrocarbon-containing gas S1 is introduced into the reformer 2 through the inlet chamber 1 and the distribution hole 102 in sequence; at the same time, the oxidant is introduced into the reformer 2 through the process burner 3; the high-temperature hydrocarbon-containing gas passes through the non-catalytic The partial oxidation reaction generates syngas mainly composed of CO+H ₂ ; the high-temperature syngas S4 exiting the reformer 2 passes through the waste heat boiler 4 to by-produce high-pressure steam, and the cooled syngas S5 exiting the waste heat boiler 4 enters the downstream device.

The process burner 3 is a double channel, wherein the inner channel is the oxidant S2 channel, and the outer channel is the auxiliary gasification agent S3 channel;

The process burner 3 is connected to the inlet cavity 1 through the burner flange 301;

The inlet chamber 1 is connected with the reformer 2 through the inlet chamber flange 101 .

For a lignite gasification synthesis gas plant in a plant, fixed bed gasification is used. Methane and tar, benzene, phenol and other components contained in the syngas exiting the fixed-bed gasifier, and the syngas enters the non-catalytic partial oxidation reformer of the present invention for further conversion into CO and H ₂ .

The temperature of the syngas exiting the fixed-bed gasifier is 230°C, the operating pressure of the non-catalytic partial oxidation reformer is 4.0MPaG, and the material of the non-catalytic partial oxidation reformer is lined with refractory bricks.

Taking a device that processes 1,000 tons of coal (dry basis) per day as an example, Table 1 shows the gas composition of the fixed-bed gasification and the gas composition of the non-catalytic partial oxidation reformer. The synthesis gas exiting the fixed bed gasifier has been treated at high temperature, and it no longer contains tar, benzene, phenols and other organic substances. Table 2 The sum of fixed bed gasification and non-catalytic partial oxidation considering the consumption of fixed bed gasification From the gasification process index, overall, the cold gas efficiency is comparable to Shenfu coal-water slurry entrained bed gasification technology widely used in China Rather, it should be said that this technology is suitable for producing syngas from carbonaceous raw materials such as lignite.

Table 1 Composition of Syngas

Table 2 Total gasification process index of fixed gasification and non-catalytic partial oxidation

The present invention has been described in detail above, and its purpose is to allow those familiar with the technology in this field to understand the content of the present invention and implement it, and can not limit the protection scope of the present invention with this. Equivalent changes or modifications shall fall within the protection scope of the present invention.

Claims (8)

1. the method that a high temperature gas containing hydrocarbon prepares synthesis gas, it is characterised in that comprise the steps:

High temperature gas containing hydrocarbon (S1) passes sequentially through entrance cavity (1), distribution hole (102) introduces reburner (2); Meanwhile, oxidant is introduced reburner (2) by process burner (3); High temperature gas containing hydrocarbon is generated by non-catalytic partial oxidation reaction with CO+H in reburner (2)₂It it is main synthesis gas;

Going out the high-temperature synthesis gas (S4) of reburner (2) by waste heat boiler (4) by-product high-pressure steam, after going out the cooling of waste heat boiler (4), synthesis gas (S5) enters downstream unit;

Wherein, process burner (3) is the dual pathways including internal channel and outer tunnel, is oxidant (S2) passage in internal channel, and outer tunnel is auxiliary gasifying agent (S3) passage;

Process burner (3) is connected with entrance cavity (1) by burner flange (301);

Entrance cavity (1) is connected with reburner (2) by entrance cavity flange (101).

2. method according to claim 1, it is characterised in that described high temperature gas containing hydrocarbon is the gas-phase product of pyrolysis or fixed bed gasification, containing Organic substance.

3. method according to claim 2, it is characterised in that described high temperature gas containing hydrocarbon is rubbish, biomass, brown coal or bituminous coal, described Organic substance is methane, tar, benzene or phenol.

4. method according to claim 1, it is characterised in that described oxidant is oxygen, air or oxygen-enriched air.

5. method according to claim 1, it is characterised in that the medium of auxiliary gasifying agent (S3) passage of described process burner is water vapour, CO₂、N₂Or aqueous water.

6. method according to claim 1, it is characterised in that the material of the side towards the fire lining of described reburner (2) is refractory brick.

7. method according to claim 1, it is characterised in that described waste heat boiler (4) is water-tube boiler or multitubular boiler.

8. method according to claim 1, it is characterised in that the operating pressure of described reburner (2) is 0.1～12MPa; The temperature of described high temperature gas containing hydrocarbon (S1) is 300～800 DEG C; Described go out reburner (2) the temperature of high-temperature synthesis gas (S4) be 900～1700 DEG C; Described go out waste heat boiler (4) cooling after the temperature of synthesis gas (S5) be 200～400 DEG C.