CN111686635A - Integrated granulation drying method for coking desulfurization sulfur foam and desulfurization waste liquid - Google Patents

Abstract

The invention belongs to the technical field of desulfurization waste liquid and sulfur foam treatment, and discloses an integrated granulation and drying method for coking desulfurization foam and desulfurization waste liquid. In the liquid, a stable suspension is formed; the obtained suspension is dripped or sprayed into cold water or a certain concentration of electrolyte solution to form a gel ball, and solidified in the solution for a certain period of time; The obtained gel balls are dried at a certain temperature to obtain salt-containing coarse sulfur spherical particles with no agglomeration, no moisture absorption, and uniform particles. The present invention adopts the dropping ball method or the spraying method to make the gel ball, and then obtains the salt-containing coarse sulfur spherical particles after drying. The technology not only has simple process flow, low operation requirements, low equipment investment cost, simple maintenance, and low operating cost. The salt-containing coarse sulfur spherical particles obtained by this process can be dried at a higher temperature, which is beneficial to improve the production efficiency.

Description

An integrated granulation and drying method for coking desulfurization foam and desulfurization waste liquid

technical field

The invention belongs to the technical field of desulfurization waste liquid and sulfur foam treatment, and particularly relates to an integrated granulation and drying method for coking desulfurization foam and desulfurization waste liquid.

Background technique

At present, desulfurization waste liquid and sulfur foam are by-products in the desulfurization process using wet oxidation method (HPF method) in coking enterprises. It contains a lot of inorganic and organic pollutants, such as thiocyanate, phenol and its derivatives are highly toxic substances, thiosulfate and elemental sulfur are easily oxidized, release sulfur dioxide, and pollute the atmosphere. If it is directly discharged into the environment, it will not only release irritating odor, cause serious pollution to the surrounding environment, affect the breathing of animals and the growth of plants, but also cause serious waste of resources.

Since the desulfurization waste liquid contains a large amount of inorganic salts, the composition is complex, and it has strong corrosiveness; while the sulfur foam also contains a large amount of salt impurities, the purity is not high, and the comprehensive utilization efficiency is low. Therefore, the desulfurization waste liquid and sulfur Foam is currently the most difficult type of industrial waste to deal with, which seriously restricts the long-term development of coking enterprises. At present, the comprehensive utilization methods of coking desulfurization and sulfur foam mainly include the following categories.

(1) The sulfur foam is directly incinerated into SO ₂ gas, and further processed into industrial sulfuric acid. The core of this technology is to incinerate and decompose sulfur foam and its desulfurization waste liquid at high temperature, and then recover SO ₂ gas. The advantages are that the process flow is short, the production process is continuous, the sulfur foam and the desulfurization waste liquid are treated at the same time, and the waste treatment and sulfur resource utilization are realized. However, this technology also has significant shortcomings that are difficult to overcome. On the one hand, the thermal energy consumption is extremely high and the operating cost is very high; on the other hand, a large amount of water is vaporized during the incineration process, and the water vapor needs to be removed during the purification process, which consumes energy repeatedly, so it is economically unreasonable; In addition, a large amount of water vapor is generated in the process, and it contacts with a small amount of SO ₃ and SO ₂ to generate dilute sulfuric acid and sulfurous acid, which will seriously corrode equipment and process pipelines, so the equipment investment cost is high; finally, this technology will involve Foreign technology patents are not only expensive to use, but also the key equipment and catalysts need to be imported. They are technically controlled by others and need to rely on foreign technology for long-term maintenance. Troubleshooting and maintenance are more troublesome.

(2) First, the coke oven gas is desulfurized by the vacuum potassium carbonate method, and then the resolved H ₂ S gas is incinerated to generate SO ₂ by the Topsoe technology, and finally sulfuric acid is produced by the condensation technology. This technology requires the construction of a complete desulfurization and acid production unit, which not only requires a large investment, but also has many disadvantages in the actual operation process. The discharge standard required by the national environmental protection regulations, and there is a hidden danger of producing potassium cyanide, a highly toxic substance, which brings serious harm to workers' health and soil and water pollution, and the difficulty of sewage treatment has become a new environmental problem _; The content of SO ₂ gas produced by S gas is low, and it is difficult to maintain self-heat balance when it is converted into SO ₃ for acid production, and the supplementary heat also increases production costs and equipment investment virtually.

(3) Claus sulfur recovery process. This process uses absorption method to desulfurize, and then burns the desorbed H ₂ S gas in a Claus furnace to oxidize part of the H ₂ S to SO ₂ , and the SO ₂ reacts with the remaining unreacted H ₂ S on the catalyst. Sulfur is formed. The sulfur recovered by this process is of high purity, which can reach the quality index of commercial-grade industrial sulfur, and can be directly used to produce industrial sulfuric acid by traditional acid-making technology. However, this method has complex technological process, high operation requirements, high equipment investment cost and high operating cost.

(4) Simultaneous solidification of desulfurization waste liquid and sulfur foam, and direct incineration of solid crude sulfur to make acid is a method of making acid from sulfur-containing waste. The key technologies of this process mainly include sulfur foam solidification and drying recovery technology, solid crude sulfur direct incineration technology, waste heat recovery, acid cleaning technology, "3+2" two-turn and two-suction technology, etc.

The invention patent (CN201410820970.6) discloses a drying method for coking desulfurization foam and desulfurization waste liquid. In the method, the desulfurization waste liquid and the sulfur foam are spray-dried at the same time by using a spray drying tower to obtain the salt-containing coarse sulfur powder. However, the disadvantage of this method is that, on the one hand, the temperature in the spray drying process is relatively high, so that the elemental sulfur in the sulfur foam is easily melted, and the phenomenon of sticking to the wall occurs in the drying tower. Although a purging device (or an air hammer) can be installed in the tower body, the use of compressed air to blow off the fine powder adsorbed on the inner wall of the tower can alleviate the problem of sticking to the wall to a certain extent. However, the purging device itself will also have accumulated materials that cannot be removed in time. After a long time, this part of the accumulated materials will be in the high temperature area for a long time, which may turn yellow, coke, and deteriorate. It will fall into the product and cause pollution to the material. In severe cases, the product may even be damaged. On the other hand, since elemental sulfur is flammable, in the spray drying process, the sulfur powder is prone to form static electricity due to mutual friction, which leads to the risk of spontaneous combustion or even explosion in the spray drying tower.

Through the above analysis, the existing problems and defects in the prior art are: because the components in the desulfurization waste liquid and sulfur foam are complex, and many components have strong toxicity and corrosiveness. On the one hand, the existing treatment methods have complex processes, high energy consumption, serious equipment corrosion, and high operating costs; on the other hand, the products obtained after treatment contain many impurities, low added value, and small market space. More importantly, there is a high risk of flammability and explosion in the treatment process, and the sulfur cycle is increased, resulting in secondary pollution. Therefore, the coking industry currently does not have an economical, safe, feasible and universal technology for the integrated harmless treatment of desulfurization waste liquid and sulfur foam, which has become a major bottleneck restricting the healthy development and technological upgrading of the current coking industry.

The technical problem to be solved by the present invention is to provide an integrated drying method for coking desulfurization foam and desulfurization waste liquid which is universal, simple, efficient, low in cost and free of flammable and explosive risks. The method can dry the desulfurization waste liquid and sulfur foam together to obtain uniform salt-containing coarse sulfur spherical particles, which is easy to store and transport, and provides a new solution for the treatment and utilization of desulfurization waste liquid and sulfur foam. The plan is conducive to the sustainable and green development of the coking industry.

SUMMARY OF THE INVENTION

In view of the problems existing in the prior art, the present invention provides an integrated granulation and drying method for coking desulfurization foam and desulfurization waste liquid.

The present invention is achieved in this way, an integrated granulation and drying method for coking desulfurization foam and desulfurization waste liquid, comprising:

The food colloid is added to the mixture of sulfur foam and desulfurization waste liquid with a certain solid content to form a stable suspension;

The obtained suspension is dropped into cold water or a certain concentration of electrolyte solution by dripping or spraying to form gel balls, and solidified in the solution for a certain period of time;

The cured gel balls are dried at a certain temperature to obtain salt-containing coarse sulfur spherical particles with no agglomeration, no moisture absorption, and uniform particles.

Further, the food colloid includes: one or more of gelatin, agar, xanthan gum, carrageenan, alginate, locust bean gum, guar gum, konjac gum, and pectin.

It is added to the mixed solution of sulfur foam and desulfurization waste liquid with a solid content of less than 55wt% to form a stable suspension.

The obtained suspension is dropped into cold water at 5°C to 35°C or an electrolyte solution with a concentration of 0.2 wt % to 15 wt % by dripping or spraying.

The electrolyte solution includes one or more ions containing K ⁺ , Na ⁺ , Ca ²⁺ , Mg ²⁺ , Fe ²⁺ , Fe ³⁺ .

Further, the gel balls were solidified in the solution for 10min-60min.

The cured gel balls are dried at 100°C-250°C to obtain salt-containing coarse sulfur spherical particles with no agglomeration, no moisture absorption, and uniform particles.

Another object of the present invention is to provide an integrated granulation and drying equipment for coking desulfurization foam and desulfurization waste liquid for implementing the integrated granulation and drying method for coking desulfurization foam and desulfurization waste liquid.

From the technical principle point of view, the present invention and its utility model are completely different from the existing domestic and foreign treatment schemes for desulfurization foam and desulfurization waste liquid, which can effectively circumvent foreign patent technical barriers, overcome the technical constraints of others, and need to rely on foreign countries for a long time. technical maintenance, troubleshooting and maintenance troubles and many other problems. The overall scheme is practical and feasible. It is an integrated drying method of coking desulfurization foam and desulfurization waste liquid that is universal, simple, efficient, low-cost and free of flammable and explosive risks, which is conducive to the sustainable and green development of the coking industry. .

In conjunction with all the above-mentioned technical solutions, the positive effect of the dry tail gas discharge of the present invention is shown in Table 1:

Table 1

serial number Pollutant Project GB16171-2012 Control indicators 1 sulfur dioxide 30mg/m³ <30mg/m³ 3 Nitrogen oxides 150mg/m³ <100mg/m³ 4 particulates 15mg/m³ <10mg/m³

The present invention adopts a continuous production process, so the production efficiency is higher, and it is favorable for the large-scale treatment of desulfurization waste liquid and sulfur foam in industry.

In the present invention, the desulfurization waste liquid and the sulfur foam are directly mixed, and the drop ball method or the spray method is used to drop them into gel balls, which are then dried to obtain salt-containing coarse sulfur spherical particles. The technology not only has simple process flow, low operation requirements, low equipment investment cost, simple maintenance, and low operating cost. On the other hand, the prepared salt-containing coarse sulfur particles have uniform particle size. Since the elemental sulfur is wrapped by the gel film, the subsequent drying process will not cause melting, bonding and pulverization due to excessive temperature, which effectively avoids the elemental sulfur. Therefore, the process can dry the salt-containing coarse sulfur spherical particles at a higher temperature, which is beneficial to improve the production efficiency.

The method can dry the desulfurization waste liquid and the sulfur foam together to obtain the salt-containing coarse sulfur spherical particles with uniform particles, and realize closed-loop treatment and zero discharge.

Description of drawings

In order to explain the technical solutions of the embodiments of the present application more clearly, the following will briefly introduce the drawings that need to be used in the embodiments of the present application. Obviously, the drawings described below are only some embodiments of the present application. For those of ordinary skill in the art, other drawings can also be obtained from these drawings without creative effort.

Fig. 1 is the integrated granulation drying method and system of a kind of coking desulfurization foam and desulfurization waste liquid provided by the embodiment of the present invention

2 is an effect diagram of the salt-containing coarse sulfur spherical particles provided in Example 1 of the present invention.

3 is an effect diagram of the salt-containing coarse sulfur spherical particles provided in Example 2 of the present invention.

Detailed ways

In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention, but not to limit the present invention.

In view of the problems existing in the prior art, the present invention provides an integrated granulation and drying method and system for coking desulfurization foam and desulfurization waste liquid. The present invention is described in detail below with reference to the accompanying drawings.

As shown in Figure 1, the integrated granulation drying method of coking desulfurization foam and desulfurization waste liquid provided by the present invention comprises:

First, add food colloids (one or more of gelatin, agar, xanthan gum, carrageenan, alginate, locust bean gum, guar gum, konjac gum, pectin) to a certain solid content (<55wt %) in the mixture of sulfur foam and desulfurization waste liquid to form a stable suspension. Then, drop the obtained suspension into cold water (5°C-35°C) or a certain concentration (0.2wt%-15wt%) electrolyte solution (containing K ⁺ , Na ⁺ , Ca ²⁺ ) by dropping or spraying , Mg ²⁺ , Fe ²⁺ , Fe ³⁺ one or more ions), form gel balls, and solidify in solution for a certain time (10min-60min). Finally, the cured gel balls are dried at a certain temperature (100° C.-250° C.) to obtain salt-containing coarse sulfur spherical particles with no agglomeration, no moisture absorption, and uniform particles.

The integrated granulation and drying method and system for coking desulfurization foam and desulfurization waste liquid provided by the present invention can also be implemented by those skilled in the industry by other steps. The present invention in FIG. 1 only provides a specific example. .

The present invention will be further described below in conjunction with specific embodiments.

Example 1:

First, 0.5wt% carrageenan powder was dissolved in a mixed solution of sulfur foam and desulfurization waste liquid with a solid content of 40% to form a stable suspension. Then, the obtained suspension was dropped dropwise into a 0.6 wt % KCl solidified solution with a dropper to form gel balls, which were solidified in the solidified solution for 60 min. Finally, the cured gel spheres are dried at 150°C to obtain salt-containing coarse sulfur spherical particles with a particle size of about 1.6-2 mm, which are not agglomerated, do not absorb moisture, and have uniform particles (Figure 2).

Example 2:

First, 1.5wt% agar powder was dissolved in a mixed solution of sulfur foam and desulfurization waste liquid with a solid content of 40% to form a stable suspension. Then, the obtained suspension was atomized and dropped into a 1 wt% FeCl ₃ solution with a centrifugal atomizer to form gel spheres, which were solidified in the solidified solution for 10 min. Finally, the cured gel spheres were dried at 150°C to obtain salt-containing coarse sulfur spherical particles with a particle size of about 0.1-1 mm without agglomeration, without moisture absorption, and with uniform particles (Figure 3).

Example 3:

First, 2wt% of xanthan gum and konjac gum mixed powder (mass ratio is xanthan gum: konjac gum=6:4) is dissolved in the mixed solution of sulfur foam and desulfurization waste liquid with a solid content of 30% to form a stable suspension. Then, the obtained suspension was dropped dropwise into a 2 wt% KCl solution with a centrifugal atomizer to form gel spheres, which were solidified in the solidified solution for 30 min. Finally, the cured gel spheres are dried at 220° C. to obtain salt-containing coarse sulfur spherical particles with a particle size of about 0.1-0.4 mm that are not agglomerated, do not absorb moisture, and have uniform particles.

Example 4:

First, 4wt% sodium alginate powder was dissolved in a mixed solution of sulfur foam and desulfurization waste liquid with a solid content of 30% to form a stable suspension. Then, the obtained suspension was dropped dropwise into a 15 wt% MgCl ₂ solution using a centrifugal atomizer to form gel spheres, which were solidified in the solidified solution for 10 min. Finally, the cured gel spheres are dried at 250° C. to obtain salt-containing coarse sulfur spherical particles with a particle size of about 0.1-0.3 mm that are not agglomerated, do not absorb moisture, and have uniform particles.

The drying methods of Examples 5-6 are the same as those of Examples 1-4, and the specific parameters are shown in Table 2.

Table 2

In the description of the present invention, unless otherwise specified, "plurality" means two or more; the terms "first", "second", "third" etc. are only used for the purpose of description, not understood as indicating or implying relative importance.

The above are only specific embodiments of the present invention, but the protection scope of the present invention is not limited to this. Any person skilled in the art is within the technical scope disclosed by the present invention, and all within the spirit and principle of the present invention Any modifications, equivalent replacements and improvements made within the scope of the present invention should be included within the protection scope of the present invention.

Claims (8)

1. The integrated granulation and drying method for the coking desulfurization sulfur foam and the desulfurization waste liquid is characterized by comprising the following steps of:

adding food colloid into a mixed solution of sulfur foam with a certain solid content and desulfurization waste liquid to form a stable turbid liquid;

dripping the obtained suspension into cold water or electrolyte solution with certain concentration in a dripping or spraying manner to form gel balls, and solidifying in the solution for a certain time;

and drying the solidified gel spheres at a certain temperature to obtain the coarse saliferous sulfur spherical particles which are not agglomerated, do not absorb moisture and are uniform in particles.

2. The integrated process for granulation and drying of coked desulfurization sulfur foam and desulfurization waste liquid according to claim 1, wherein the food colloid comprises: one or more of gelatin, agar, xanthan gum, carrageenan, alginate, locust bean gum, guar gum, konjac gum and pectin.

3. The integrated granulation and drying method for coking desulfurization sulfur foam and desulfurization waste liquid according to claim 1, wherein the solid content of the mixture of desulfurization sulfur foam and desulfurization waste liquid is less than 55 wt%.

4. The integrated granulation and drying method for coking desulfurization sulfur foam and desulfurization waste liquid according to claim 1, characterized in that the obtained suspension is dropped into cold water of 5 ℃ to 35 ℃ or an electrolyte solution with a concentration of 0.2 wt% to 15 wt% in a dropping or spraying manner.

5. The integrated process of granulation and drying of coked desulfurization sulfur foam and desulfurization waste liquid of claim 1, wherein the electrolyte solution comprises K-containing⁺、Na⁺、Ca²⁺、Mg²⁺、Fe²⁺、Fe³⁺One or more ions of (a).

6. The integrated granulation drying method of coking desulfurization sulfur foam and desulfurization waste liquid as described in claim 1, wherein the gel beads are solidified in the solution for 10min to 60 min.

7. The integrated granulation drying method of coking desulfurization sulfur foam and desulfurization waste liquid as described in claim 1, wherein the solidified gel spheres are dried at 100 ℃ to 250 ℃ to obtain salt-containing coarse sulfur spherical particles which are non-caking, non-hygroscopic and uniform in particle size.

8. An integrated granulation drying apparatus for coking desulfurization sulfur foam and desulfurization waste liquid, which implements the integrated granulation drying method for coking desulfurization sulfur foam and desulfurization waste liquid according to claims 1 to 7.

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