An improved method of producing coal ash brick carbonized blocks in combination with a coal gas shift process

Abstract

The application discloses a method for producing carbonized fly ash brick by improved coal gas shift process, which comprises the following steps: 35-80% carbon monoxide in the coal gas enters a first shift tower in a way of water vapor:carbon monoxide 1.2-1.5:1, the carbon monoxide is reduced to 15-27% by the first shift, the temperature is adjusted to be lower than 350 DEG C, the indirect heating is sent to a basic magnesium carbonate water regeneration tower 1, the water absorbed by the regenerated basic magnesium carbonate is above 250 DEG C steam, meanwhile, the temperature of the reduced shift gas 1 is 20-30 DEG C higher than the steam temperature, the shift gas 1 is sent to at least two carbon dioxide absorption towers containing fly ash cement compressed blocks to absorb carbon dioxide, the carbon dioxide in the shift gas 1 is reduced by 20-85%, the outlet gas of the absorption tower and the steam generated by the basic magnesium carbonate regeneration tower 1 are sent to second and third shift furnaces, the carbon monoxide is reduced to 0.5-1.5% by the second and third shifts, and the gas is called water-rich shift gas and is directly sent to at least two water vapor absorption towers 2 containing basic magnesium carbonate to absorb water vapor and then sent to a later section, and the application is beneficial to realize the recovery of the water vapor in the shift gas and the solidification of part of the carbon dioxide.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of chemical production, building materials, energy saving and environmental protection, and particularly relates to a method for producing carbonized brick blocks by improved coal gas shift process. BACKGROUND

[0002] The raw material gas prepared from natural gas, residual oil and coal always contains a certain amount of carbon monoxide, for example, the semi-water gas prepared from solid fuel gasification contains 25% to 40% of carbon monoxide, the water gas prepared from heavy oil gasification contains 44% to 49% of carbon monoxide, and the coal gas shift refers to the conversion of carbon monoxide in the coal gas into carbon dioxide and hydrogen under the action of a catalyst at a certain temperature.

[0003] The ash powder collected from the coal furnace and flue gas is called fly ash. The fly ash has small particles, and the use of the fly ash for blending brick can reduce the crushing process and save labor. The fly ash sintered brick is a load-bearing masonry material prepared by mixing more than 30% of fly ash in clay raw materials, stirring, molding, drying and baking, and has the characteristics of saving clay, saving fuel and protecting the environment. Because the material properties are completely the same as those of sintered clay bricks, and the weight is lighter than that of the latter, the fly ash sintered brick is a new type of sintered wall material which is easy to popularize and apply.

[0004] CN113634114A Zhao Jing et al. discloses a method for capturing CO2 in flue gas by using fly ash, which comprises the following steps: S1, conveying fly ash from the ash storage to the stirring tank and adding water to stir and prepare slurry to obtain fly ash slurry A; S2, conveying the fly ash slurry A to the ultrafine grinder for grinding treatment to obtain fly ash slurry B; S3, mixing the fly ash slurry B, flue gas and additives for carbonation reaction; S4, separating the mixed slurry after reaction to obtain high-concentration ash slurry, and the circulating water produced by separation is sent to the slurry preparation link for recycling, and the flue gas after reaction is sent back to the chimney. The method for capturing CO2 in flue gas by using fly ash can capture CO2 in flue gas, and the high-concentration ash slurry prepared can be used for resource utilization in coal mine goaf backfilling, cement and roadbed, etc., has the characteristics of simple system, short process, small land occupation, low investment and operation cost, can realize waste treatment with waste, and has wide application prospect.

[0005] CN115650162A Liu Pan et al. discloses a converter flue gas efficient recycling method, comprising the following steps: S1, the high-temperature flue gas out of the converter is sequentially introduced into the flue gas cooling device and the flue gas dust removal device through the furnace mouth smoke cover, and the converter flue gas after dust removal by the flue gas dust removal device enters the coal gas shift device; S2, in the coal gas shift device, the converter flue gas and the injected water vapor react to generate hydrogen and carbon dioxide under the action of the catalyst; S3, the flue gas discharged from the coal gas shift device is sequentially sent into the ammonia synthesis device after passing through the cooling device, the decarburization device and the pressurizing device to synthesize ammonia. The invention utilizes the conversion of carbon monoxide in the converter flue gas into hydrogen under the action of the catalyst, and the reaction of hydrogen and nitrogen in the flue gas under high pressure to generate ammonia, realizing the efficient utilization of converter flue gas from fuel to raw material.

[0006] CN111217566B Lin Zhongcai et al. discloses a method for preparing high-temperature-resistant concrete blocks using carbon dioxide, comprising the following steps: (1) the materials for preparing concrete blocks are dry-mixed uniformly in a mixer according to a certain proportion, water is slowly added to the obtained mixture and stirred uniformly; (2) a certain mass of the mixture is weighed and added to a block machine for pressing and forming; (3) the formed concrete blocks are placed in a carbon dioxide curing box for curing, the curing conditions are temperature 20℃, relative humidity 65%, and carbon dioxide concentration 20%, and the curing is performed to the specified age. The invention can improve the high-temperature resistance of concrete blocks, effectively reduce the external damage of concrete blocks at high temperature, effectively improve the strength of concrete blocks after high temperature, effectively utilize the waste greenhouse gas carbon dioxide gas, reduce greenhouse gas emissions, and protect the environment and curb the occurrence of greenhouse effect.

[0007] In view of the prior art, the coal gas shift process does not recover water vapor, consumes a large amount of water vapor, and uses fly ash to directly capture and solidify carbon dioxide in flue gas, with low capture efficiency. To solve this problem and save energy consumption, the following method is invented. SUMMARY

[0008] The application discloses a method for producing carbonized fly ash brick by an improved coal gas shift process, characterized in that the carbon monoxide in the coal gas component is 35-80%, the fresh water vapor and the carbon monoxide enter a first shift tower in a mode of 1.2-1.5:1, the carbon monoxide in the gas is reduced to 15-27% after the first stage shift and is called first shift gas, the temperature is adjusted to be lower than 350 DEG C, the first shift gas is sent to an alkaline magnesium carbonate regeneration tower to absorb water in the regenerated alkaline magnesium carbonate and generate steam above 250 DEG C, the temperature of the cooled first shift gas is 20-30 DEG C higher than the temperature of the steam, the first shift gas is sent to at least two carbon dioxide absorption towers containing compressed fly ash cement blocks to absorb carbon dioxide, the carbon dioxide in the first shift gas is reduced by 20-85%, the gas outlet of the carbon dioxide absorption tower is connected with the steam generated by the alkaline magnesium carbonate regeneration tower and is sent to a second shift furnace and a third shift furnace, the carbon monoxide is reduced to 0.5-1.5% after the second stage shift and the third stage shift and is called water-rich shift gas, the water-rich shift gas is directly sent to at least two water vapor absorption towers containing alkaline magnesium carbonate to absorb water vapor and is sent to a downstream section, so that the water vapor in the shift gas is recycled and utilized and part of the carbon dioxide is solidified.

[0009] Compared with the prior art, the application has the following advantages:

[0010] (1) The application provides a method for producing carbonized fly ash brick by an improved coal gas shift process, carbon dioxide is sealed in the fly ash brick under high temperature and high pressure conditions, and the strength of the prepared fly ash carbonized brick is greatly improved.

[0011] (2) The application reduces the emission of carbon dioxide and the influence of carbon dioxide on the atmospheric environment by solidifying the carbon dioxide in the fly ash brick.

[0012] (3) The application solidifies the carbon dioxide in the first stage shift gas in the fly ash brick, and the consumption of water vapor in the subsequent shift process is reduced.

[0013] (4) The water vapor in the second stage shift process is partly recovered from the water-rich shift gas, and the amount of external water vapor is saved. BRIEF DESCRIPTION OF DRAWINGS

[0014] Figure 1 It is a flow chart of the method for producing carbonized fly ash brick by an improved coal gas shift process EMBODIMENT

[0015] Following, the embodiments of the present application are illustrated by specific examples, and other advantages and effects of the present application can be easily understood by those skilled in the art from the disclosure of this specification. The present application can also be implemented or applied by other different specific embodiments, and the details in this specification can be modified or changed in various ways based on different views and applications without departing from the spirit of the present application. It should be noted that the following examples and features in the examples can be combined with each other without conflict.

[0016] Example 1: The coal gas component contains 78% carbon monoxide. Fresh steam is introduced into the first shift converter at a ratio of 1.2:1 of steam to carbon monoxide in the coal gas. After the first shift, the carbon monoxide in the gas is reduced to 21%, which is called the first shift gas. The temperature is adjusted to 320°C, and the first shift gas is sent to the lime-magnesium hydroxide water regeneration tower to indirectly heat the lime-magnesium hydroxide to regenerate the water absorbed therein, and generate 250°C steam at the same time. The temperature of the cooled first shift gas is 275°C, and the first shift gas is sent to the carbon dioxide absorption tower containing compressed ash cement blocks to absorb carbon dioxide. The first shift gas is reduced by 40% of carbon dioxide. The gas outlet of the absorption tower and the steam generated by the lime-magnesium hydroxide regeneration tower are sent to the second and third shift converters. After the second and third shifts, the carbon monoxide is reduced to 1.5%, which is called the water-rich shift gas. The water-rich shift gas is directly sent to the water vapor absorption tower containing lime-magnesium hydroxide, and after absorbing water vapor, it is sent to the downstream section, thereby realizing the recycling of water vapor in the shift gas and the solidification of part of the carbon dioxide.

[0017] Example 2: The coal gas component contains 56% carbon monoxide. Fresh steam is introduced into the first shift converter at a ratio of 1.3:1 of steam to carbon monoxide in the coal gas. After the first shift, the carbon monoxide in the gas is reduced to 20%, which is called the first shift gas. The temperature is adjusted to 320°C, and the first shift gas is sent to the lime-magnesium hydroxide water regeneration tower to indirectly heat the lime-magnesium hydroxide to regenerate the water absorbed therein, and generate 260°C steam at the same time. Meanwhile, the temperature of the cooled first shift gas is 280°C, and the first shift gas is sent to the carbon dioxide absorption tower containing compressed fly ash cement blocks to absorb carbon dioxide. The first shift gas is reduced by 35% of carbon dioxide. The gas outlet of the absorption tower and the steam generated by the lime-magnesium hydroxide regeneration tower are sent to the second and third shift converters. After the second and third shifts, the carbon monoxide is reduced to 1.2%, which is called the water-rich shift gas. The water-rich shift gas is directly sent to the water vapor absorption tower containing lime-magnesium hydroxide, and after absorbing water vapor, it is sent to the downstream section, thereby realizing the recycling of water vapor in the shift gas and the solidification of part of the carbon dioxide.

[0018] Example 3: Coal gas component contains 72% carbon monoxide, fresh water steam: carbon monoxide in the gas is 1.5:1, which enters the first shift tower, after the first shift, the gas carbon monoxide is reduced to 22%, called the first shift gas, the temperature is adjusted to 340℃, and is sent to the basic magnesium carbonate water regeneration tower for indirect heating, to regenerate the water absorbed by the basic magnesium carbonate, generating 250℃ steam, at the same time, the temperature of the first shift gas is reduced to 280℃, and is sent to the carbon dioxide absorption tower provided with three fly ash cement compressed blocks to absorb carbon dioxide, the first shift gas is reduced by 52% carbon dioxide, and the gas outlet of the absorption tower is sent to the second and third shift furnaces together with the steam generated by the basic magnesium carbonate regeneration tower, after the second and third shifts, the carbon monoxide is reduced to 0.8%, called the water-rich shift gas, which is directly sent to the water steam absorption tower provided with three basic magnesium carbonates, after absorbing water steam, it is sent to the downstream section, thereby realizing the recycling and utilization of water steam in the shift gas and the solidification of part of the carbon dioxide.

Claims

1. A method of improved coal gas conversion process for the joint production of coal ash brick carbonized blocks, characterized by Coal gas component carbon monoxide is 35~80%, with fresh water vapor: carbon monoxide 1.2~1.5: 1 way into the first shift tower, after the first stage of transformation gas carbon monoxide reduced to 15~27% called the first shift gas, adjustment temperature <350℃, sent to the basic magnesium carbonate water regeneration tower indirect heating regeneration of water absorbed in the basic magnesium carbonate, while generating 250℃ above steam; The first shift gas temperature is higher than the temperature of steam 20~30℃, sent to at least set 2 of the carbon dioxide absorption tower containing coal ash cement compressed block to absorb carbon dioxide, the first shift gas reduced 20~85% carbon dioxide, carbon dioxide absorption tower gas outlet and steam generated by the basic magnesium carbonate regeneration tower into the second, third shift furnace, after the second stage, third stage of transformation carbon monoxide reduced to 0.5~1.5% called water-rich shift gas, water-rich shift gas directly sent to at least set 2 of the water vapor absorption tower containing basic magnesium carbonate absorption of water vapor after sending downstream section, thus realizing the shift gas water vapor recycling and part of the carbon dioxide solidification.

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