An environmentally friendly production method for preparing sulfuric acid based on sulfur dioxide conversion

Abstract

The invention discloses an environmentally friendly production method for preparing sulfuric acid based on sulfur dioxide conversion, including S1: purifying sulfur dioxide gas; S2: condensing the treated sulfur dioxide gas, removing impurities and moisture therein, and then collecting it through a condenser; S3: heating the collected sulfur dioxide liquid to 30-100°C, and converting it into sulfur dioxide gas; S4: passing the gas into an absorption solvent, and collecting the solvent; S5: heating the collected solvent to 30-100°C to obtain a high concentration of sulfur dioxide gas; S6: reacting the high concentration of sulfur dioxide gas with oxygen under the action of a catalyst to generate sulfur trioxide gas; S7: sending the sulfur trioxide gas into an absorption tower to react with water to generate sulfuric acid. The method of coating a protective layer on the surface of a vanadium catalyst of the present invention can prolong the service life of the catalyst, improve the catalytic efficiency, reduce resource waste, and realize an environmentally friendly production concept.

Description

Technical Field

[0001] The invention belongs to the technical field of sulfuric acid preparation, and specifically relates to an environmentally friendly production method for preparing sulfuric acid based on sulfur dioxide conversion. Background Art

[0002] Sulfuric acid is the chemical with the highest production volume in the world. Currently, the world produces about 700,000 tons of sulfuric acid every day. It is an important chemical and industrial raw material.

[0003] At present, the contact process is the most common method for preparing sulfuric acid and oleum, which generally includes three steps, namely (1) generating sulfur dioxide from a sulfur-containing raw material; (2) oxidizing sulfur dioxide to generate sulfur trioxide; and (3) contacting sulfur trioxide with water or concentrated sulfuric acid to generate sulfuric acid or oleum.

[0004] In the process of converting sulfur dioxide into sulfur trioxide, vanadium catalysts are usually used to accelerate the reaction progress. The catalyst is easy to react with impurities such as arsenic, fluorine, acid mist and mineral dust during use, resulting in catalyst poisoning, thereby reducing the reaction efficiency. The catalyst needs to be replaced frequently during production, resulting in resource waste and environmental pollution.

[0005] There are some methods in the prior art that attempt to solve the problem by regularly cleaning the catalyst, improving the reaction conditions, etc., but these methods cannot fundamentally solve the problem. The catalyst has a short service life, resulting in waste of resources and increasing the complexity of the production process. The sulfur dioxide reaction efficiency is low, which does not conform to the concept of environmentally friendly production. Summary of the invention

[0006] The object of the present invention is to provide an environmentally friendly production method for preparing sulfuric acid based on the conversion of sulfur dioxide, so as to solve the problems raised in the above background technology.

[0007] To achieve the above object, the present invention provides the following technical solution: an environmentally friendly production method for preparing sulfuric acid based on sulfur dioxide conversion, comprising the following steps:

[0008] S1: purify sulfur dioxide gas;

[0009] S2: condense the treated sulfur dioxide gas to remove impurities and moisture, and then collect it through a condenser;

[0010] S3: heating the collected sulfur dioxide liquid to 30-100° C. to convert it into sulfur dioxide gas;

[0011] S4: passing the above gas into an absorption solvent and collecting the solvent;

[0012] S5: heating the collected solvent to 30-100° C. to obtain high-concentration sulfur dioxide gas;

[0013] S6: reacting high concentration sulfur dioxide gas with oxygen under the action of a catalyst to generate sulfur trioxide gas;

[0014] S7: The sulfur trioxide gas is sent into the absorption tower to react with water to generate sulfuric acid.

[0015] Preferably, in step S1, the sulfur dioxide gas is purified to remove solid particles in the gas.

[0016] In any of the above schemes, preferably, in step S2, sulfur dioxide gas is introduced into the channel, and the periphery of the channel is filled with low-temperature liquid, so that the sulfur dioxide gas is cooled from the channel until it reaches the condensation point and condenses.

[0017] Preferably in any of the above schemes, in step S4, the solvent is diethyl ethyl phosphate.

[0018] In any of the above schemes, preferably, in step S6, the catalyst is a vanadium catalyst with a surface coated with silicon dioxide.

[0019] In any of the above schemes, it is preferred that the vanadium catalyst is V2O5.

[0020] In any of the above schemes, preferably, the method for preparing the vanadium catalyst coated with silicon dioxide on the surface comprises:

[0021] S11: Use a screening machine to select a vanadium catalyst cylinder with a clean surface as a substrate to ensure that there is no impurity interference on the catalyst surface before coating;

[0022] S12: controlling the pore size of the porous silica material to be 100-700 nm to obtain a porous silica coating material;

[0023] S13: Use a coating machine to evenly coat the porous silica coating on the surface of the vanadium catalyst to ensure that each catalyst particle is effectively covered;

[0024] S14: Dry the coated catalyst with a hot air dryer and cure the catalyst by irradiating ultraviolet rays.

[0025] Preferably, in any of the above schemes, in step S12, the temperature and time of the sol-gelling are 90° C. and 30-60 min.

[0026] Preferably, in any of the above schemes, in step S13, the calcination temperature is 500-550° C. and the calcination time is 3-5 hours.

[0027] The technical effects and advantages of the present invention are as follows: the environmentally friendly production method for preparing sulfuric acid based on the conversion of sulfur dioxide uses a new type of catalyst in the process of converting sulfur dioxide into sulfur trioxide. The vanadium catalyst is coated with silicon dioxide on the surface for catalysis. A porous protective layer is formed on the surface of the vanadium catalyst to achieve a porous structure and high adhesion ability of the coating. Under the premise of not affecting the catalytic effect of the catalyst, a balance between gas permeability and poison blocking effect is achieved. In addition, the catalyst is coated and cured to ensure that the protective layer does not fall off during a long reaction process. DETAILED DESCRIPTION

[0028] The specific embodiments of the present invention are further described below. It should be noted that the description of these embodiments is used to help understand the present invention, but does not constitute a limitation of the present invention. In addition, the technical features involved in each embodiment of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0029] Embodiment 1:

[0030] An environmentally friendly production method for preparing sulfuric acid based on sulfur dioxide conversion comprises the following steps:

[0031] S1: Purify sulfur dioxide gas to remove solid particles in the gas;

[0032] S2: The treated sulfur dioxide gas is passed into liquid nitrogen for condensation to remove impurities and moisture therein, and the sulfur dioxide gas is passed into a channel, and the periphery of the channel is filled with low-temperature liquid, so that the sulfur dioxide gas is cooled from the channel until it reaches the condensation point and condenses, and is collected by a condenser;

[0033] S3: heating the collected sulfur dioxide liquid to 40° C. to convert it into sulfur dioxide gas;

[0034] S4: passing the above gas into an absorption solvent and collecting the solvent, wherein the solvent is diethyl ethyl phosphate;

[0035] S5: heating the collected solvent to 40° C. to obtain high-concentration sulfur dioxide gas;

[0036] S6: reacting high concentration sulfur dioxide gas with oxygen under the action of a catalyst to generate sulfur trioxide gas;

[0037] S7: The sulfur trioxide gas is sent into the absorption tower to react with water to generate sulfuric acid.

[0038] Embodiment 2:

[0039] An environmentally friendly production method for preparing sulfuric acid based on sulfur dioxide conversion comprises the following steps:

[0040] S1: Purify the sulfur dioxide gas and use a dust collector to remove solid particles in the gas;

[0041] S2: The treated sulfur dioxide gas is passed into liquid nitrogen for condensation to remove impurities and moisture therein, and the sulfur dioxide gas is passed into a channel, and the periphery of the channel is filled with low-temperature liquid, so that the sulfur dioxide gas is cooled from the channel until it reaches the condensation point and condenses, and is collected by a condenser;

[0042] S3: heating the collected sulfur dioxide liquid to 60° C. to convert it into sulfur dioxide gas;

[0043] S4: passing the above gas into an absorption solvent and collecting the solvent, wherein the solvent is diethyl ethyl phosphate;

[0044] S5: heating the collected solvent to 60° C. to obtain high-concentration sulfur dioxide gas;

[0045] S6: reacting high concentration sulfur dioxide gas with oxygen under the action of a catalyst to generate sulfur trioxide gas;

[0046] S7: The sulfur trioxide gas is sent into the absorption tower to react with water to generate sulfuric acid.

[0047] Embodiment 3:

[0048] An environmentally friendly production method for preparing sulfuric acid based on sulfur dioxide conversion comprises the following steps:

[0049] S1: Purify sulfur dioxide gas to remove solid particles in the gas;

[0050] S2: The treated sulfur dioxide gas is passed into liquid nitrogen for condensation to remove impurities and moisture therein, and the sulfur dioxide gas is passed into a channel, and the periphery of the channel is filled with low-temperature liquid, so that the sulfur dioxide gas is cooled from the channel until it reaches the condensation point and condenses, and is collected by a condenser;

[0051] S3: heating the collected sulfur dioxide liquid to 90° C. to convert it into sulfur dioxide gas;

[0052] S4: passing the above gas into an absorption solvent and collecting the solvent, wherein the solvent is diethyl ethyl phosphate;

[0053] S5: heating the collected solvent to 90° C. to obtain high-concentration sulfur dioxide gas;

[0054] S6: reacting high concentration sulfur dioxide gas with oxygen under the action of a catalyst to generate sulfur trioxide gas;

[0055] S7: The sulfur trioxide gas is sent into the absorption tower to react with water to generate sulfuric acid.

[0056] Embodiment 4:

[0057] The present invention also provides a method for preparing a vanadium catalyst (V2O5) coated with silicon dioxide on the surface, comprising:

[0058] S11: Use a screening machine to select a vanadium catalyst cylinder with a clean surface as a substrate to ensure that there is no impurity interference on the catalyst surface before coating;

[0059] S12: controlling the pore size of the porous silica material to be 100 nm to obtain a porous silica coating material;

[0060] S13: Use a coating machine to evenly coat the porous silica coating on the surface of the vanadium catalyst to ensure that each catalyst particle is effectively covered;

[0061] S14: Dry the coated catalyst with a hot air dryer and cure the catalyst by irradiating ultraviolet rays.

[0062] Embodiment 5:

[0063] The present invention also provides a method for preparing a vanadium catalyst (V2O5) coated with silicon dioxide on the surface, comprising:

[0064] S11: Use a screening machine to select a vanadium catalyst cylinder with a clean surface as a substrate to ensure that there is no impurity interference on the catalyst surface before coating;

[0065] S12: controlling the pore size of the porous silica material to be 500 nm to obtain a porous silica coating material;

[0066] S13: Use a coating machine to evenly coat the porous silica coating on the surface of the vanadium catalyst to ensure that each catalyst particle is effectively covered;

[0067] S14: Dry the coated catalyst with a hot air dryer and cure the catalyst by irradiating ultraviolet rays.

[0068] Embodiment 6:

[0069] The present invention also provides a method for preparing a vanadium catalyst (V2O5) coated with silicon dioxide on the surface, comprising:

[0070] S11: Use a screening machine to select a vanadium catalyst cylinder with a clean surface as a substrate to ensure that there is no impurity interference on the catalyst surface before coating;

[0071] S12: controlling the pore size of the porous silica material to be 100-700 nm to obtain a porous silica coating material;

[0072] S13: Use a coating machine to evenly coat the porous silica coating on the surface of the vanadium catalyst to ensure that each catalyst particle is effectively covered;

[0073] S14: Dry the coated catalyst with a hot air dryer and cure the catalyst by irradiating ultraviolet rays.

[0074] Comparative Example:

[0075] Liquid sulfur is used as raw material, and after temperature control and heat exchange, gaseous 100% SO3 is obtained by distillation. The distillation process is carried out under slight boiling. The heat source is the conversion system cold and hot heat exchanger to control the conversion temperature. The gaseous 100% SO3 is countercurrently contacted with 105% oleum in the packed tower and absorbed to produce 105% oleum. The unabsorbed 100% SO3 is mixed with the conversion gas from the evaporator and sent back to the acid production system. The concentration of the circulating acid in the absorption tower increases due to the absorption of SO3, and 25% oleum is sent from the high-level tank to dilute it to maintain its 105% nicotinic acid concentration unchanged.

[0076] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. An environmentally friendly production method for preparing sulfuric acid based on the conversion of sulfur dioxide, characterized in that: The following steps are involved: S1: purify sulfur dioxide gas; S2: condense the treated sulfur dioxide gas to remove impurities and moisture, and then collect it through a condenser; S3: heating the collected sulfur dioxide liquid to 30-100° C. to convert it into sulfur dioxide gas; S4: passing the above gas into an absorption solvent and collecting the solvent; S5: heating the collected solvent to 30-100° C. to obtain high-concentration sulfur dioxide gas; S6: reacting high concentration sulfur dioxide gas with oxygen under the action of a catalyst to generate sulfur trioxide gas; S7: The sulfur trioxide gas is sent into the absorption tower to react with water to generate sulfuric acid.

2. The environmentally friendly production method for preparing sulfuric acid based on sulfur dioxide conversion according to claim 1, characterized in that: In step S1, the sulfur dioxide gas is purified to remove solid particles in the gas.

3. The environmentally friendly production method for preparing sulfuric acid based on sulfur dioxide conversion according to claim 1, characterized in that: In step S2, sulfur dioxide gas is introduced into the channel, and the periphery of the channel is filled with low-temperature liquid, so that the sulfur dioxide gas is cooled in the channel until it reaches the condensation point and condenses.

4. The environmentally friendly production method for preparing sulfuric acid based on sulfur dioxide conversion according to claim 1, characterized in that: In step S4, the solvent is diethyl ethyl phosphate.

5. The environmentally friendly production method for preparing sulfuric acid based on sulfur dioxide conversion according to claim 1, characterized in that: In step S6, the catalyst is a vanadium catalyst with a surface coated with silicon dioxide.

6. The environmentally friendly production method for preparing sulfuric acid based on sulfur dioxide conversion according to claim 5, characterized in that: The vanadium catalyst is V2O5.

7. The environmentally friendly production method for preparing sulfuric acid based on sulfur dioxide conversion according to claim 5, characterized in that: The preparation method of the vanadium catalyst coated with silicon dioxide on the surface comprises: S11: Use a screening machine to select a vanadium catalyst cylinder with a clean surface as a substrate to ensure that there is no impurity interference on the catalyst surface before coating; S12: controlling the pore size of the porous silica material to be 100-700 nm to obtain a porous silica coating material; S13: Use a coating machine to evenly coat the porous silica coating on the surface of the vanadium catalyst to ensure that each catalyst particle is effectively covered; S14: Dry the coated catalyst with a hot air dryer and cure the catalyst by irradiating ultraviolet rays.

8. The environmentally friendly production method for preparing sulfuric acid based on sulfur dioxide conversion according to claim 7, characterized in that: In step S12, the temperature and time of the sol-gelling are 90° C. and 30-60 min.

9. The environmentally friendly production method for preparing sulfuric acid based on sulfur dioxide conversion according to claim 7, characterized in that: In step S13, the calcination temperature is 500-550°C and the calcination time is 3-5h.