阅读说明：本技术 一种氨碱法纯碱生产中防止蒸馏工序预灰桶结疤的方法 (Method for preventing pre-ash barrel from scabbing in distillation process in ammonia-soda process soda ash production ) 是由 丁思颂 王军民 郭常伟 于 2020-05-25 设计创作，主要内容包括：本发明涉及纯碱生产技术领域,尤其涉及一种氨碱法纯碱生产中防止蒸馏工序预灰桶结疤的方法,预灰桶在靠近桶体底部的一侧设置回流管,石灰乳和预热母液经过预灰桶搅拌混合的调和液通过回流管从预灰桶上部的浊液回流进管进入预灰桶的内部。该方法可防止预灰桶结疤,预灰桶可实现连续、稳定运行,提高纯碱生产整个系统稳定性、连续性,降低环保风险,提高设备利用率、提高产能,从而降低制造成本。(The invention relates to the technical field of soda production, in particular to a method for preventing a pre-ash barrel from scabbing in a distillation process in ammonia-soda process soda production. The method can prevent the pre-ash barrel from scabbing, the pre-ash barrel can continuously and stably run, the stability and the continuity of the whole system for producing the sodium carbonate are improved, the environmental protection risk is reduced, the utilization rate of equipment is improved, the production capacity is improved, and therefore the manufacturing cost is reduced.)

1. A method for preventing the pre-ash barrel of the distillation process from scabbing in the production of soda by an ammonia-soda process is characterized in that: the return pipe is arranged on one side of the pre-ash barrel close to the bottom of the barrel body, and the mixed liquid obtained by stirring and mixing the lime milk and the pre-heated mother liquor through the pre-ash barrel flows back into the pre-ash barrel from the turbid liquid at the upper part of the pre-ash barrel along the return pipe under the action of the return pump.

2. The method for preventing the pre-ash barrel of the distillation process from scabbing in the ammonia-soda process soda production according to claim 1, which is characterized in that: the distance between the outlet center line of the return pipe and the bottom of the pre-ash barrel is 12-15cm, the diameter of the return pipe is 18-22cm, and the return flow of the blending liquid is 360-380m³/h。

3. The method for preventing the pre-ash barrel of the distillation process from scabbing in the ammonia-soda process soda production according to claim 1, which is characterized in that: the lime milk and the preheated mother liquor enter a separator through a blending liquid stirred and mixed by a pre-ash barrel, and bottom turbid liquid separated by the separator enters the interior of the pre-ash barrel from a turbid liquid backflow inlet pipe at the upper part of the pre-ash barrel through a backflow pump.

4. The method for preventing the pre-ash barrel of the distillation process from scabbing in the production of soda ash by an ammonia-soda process according to claim 3, wherein the method comprises the following steps: the separator comprises a body made of carbon steel, the body comprises a straight barrel section and a conical barrel section which are integrally structured and mutually communicated, and the height ratio of the straight barrel section to the conical barrel section is 2: 3; a supernatant outlet is formed in the center of the top of the straight barrel section, a mixed liquid inlet pipe is arranged on one side of the upper part of the straight barrel section along the tangential direction of the barrel body, and the distance between the central line of the mixed liquid inlet pipe and the top of the straight barrel section is 40-45 cm; the bottom center of the conical barrel section is provided with a turbid liquid outlet, and the diameter of the mixed liquid inlet pipe, the diameter of the supernatant outlet and the diameter ratio of the turbid liquid outlet are 9:8: 4.

5. The method for preventing the pre-ash barrel of the distillation process from scabbing in the production of soda ash by an ammonia-soda process according to claim 3, wherein the method comprises the following steps: the reflux quantity of the turbid liquid is 360-380m³/h。

6. The method for preventing the pre-ash barrel of the distillation process from scabbing in the production of soda by an ammonia-soda process according to claim 1 or 3, wherein the method comprises the following steps: the pre-ash barrel comprises a barrel body, wherein a turbid liquid backflow inlet pipe is arranged on one side of the upper portion of the barrel body, the distance between the central line of the turbid liquid backflow inlet pipe and the top of the barrel body is 300-350cm, the distance between the central line of the turbid liquid backflow inlet pipe and the liquid level inside the barrel body is 200-250cm, and the included angle between the central line of the turbid liquid backflow inlet pipe and the barrel wall on the side is 20-25 degrees.

Technical Field

The invention relates to the technical field of soda ash production, in particular to a method for preventing a pre-ash barrel from scabbing in a distillation process in ammonia-soda process soda ash production.

Background

The ammonia-soda process soda production enterprises generally use sea salt and limestone as raw materials for producing soda, and the sea salt contains about Ca²⁺0.29％、Mg²⁺0.12％、SO₄ ^2-0.95 percent, and in order to save fresh water resources, the seawater which is commonly used by production enterprises as the water for dissolving salt and contains about Ca²⁺0.63tt、Mg²⁺1.89tt、SO₄ ^2-0.91 tt. In the prior ammonia-soda process soda ash production process, lime milk is distilled in order to recover ammonia in preheated mother liquorAnd preheating mother liquor (the preheating mother liquor refers to a component obtained by subjecting carbonization mother liquor to twice heating distillation in the upper sections of a calcination process mother liquor combined tower and a distillation process distillation tower) and feeding the carbonization mother liquor into a pre-ash barrel to be stirred by a stirrer to promote reaction, feeding the reacted mixture into a distillation tower to be subjected to steam distillation, and distilling the distilled NH₃And CO₂The lime milk and the preheated mother liquor contain a large amount of Ca for recycling²⁺、Mg²⁺、SO₄ ^2-、CO₃ ^2-、Cl^-Plasma generates double salt scabs which take calcium sulfate as a main component, so that equipment is blocked and abraded, and the equipment is forced to be stopped, cleaned and overhauled. The operation period of the pre-ash barrel in the distillation process is mainly determined by the degree of scabbing, when the scabbing grows to a certain degree, a channel becomes small, liquid and steam are not smoothly discharged, and waste liquid runs ammonia to cause the increase of ammonia consumption, ash consumption and steam consumption, so that the manufacturing cost is increased; and the ammonia nitrogen environmental protection index of the wastewater is increased, so that the manufacturing cost is influenced and the environmental protection risk is caused. In the ammonia-soda production enterprises of the ammonia-soda process, the operation cycle of the distillation tower pre-ash barrel is about 60-90 days in the ammonia-soda enterprises using sea salt and seawater to melt salt, and the cleaning and maintenance of one distillation tower pre-ash barrel takes about 5-7 days. Stopping the tower to overhaul the pre-ash barrel will reduce the production capacity of the system, and at the same time, will cause production fluctuation and increase the overhaul and maintenance costs. Therefore, the prevention of the pre-ash barrel from scabbing is one of the important ways for reducing ammonia consumption, ash consumption, steam consumption and overhaul cost in the mother liquor ammonia distillation process and reducing the material consumption and the manufacturing cost of the soda production.

Disclosure of Invention

The technical problem to be solved by the invention is as follows: aiming at the defects in the prior art, the method for preventing the pre-ash barrel from scabbing in the distillation process in the ammonia-soda process soda production is provided, the pre-ash barrel can be prevented from scabbing, the pre-ash barrel can continuously and stably operate, the stability and the continuity of the whole soda production system are improved, the environmental protection risk is reduced, the utilization rate of equipment is improved, the production capacity is improved, and therefore the manufacturing cost is reduced.

In order to solve the technical problems, the technical scheme of the invention is as follows:

a method for preventing a pre-ash barrel from scabbing in a distillation process in the production of soda by an ammonia-soda process is characterized in that a return pipe is arranged on one side of the pre-ash barrel close to the bottom of a barrel body, and a mixed solution obtained by stirring and mixing lime milk and pre-heated mother liquor in the pre-ash barrel enters the pre-ash barrel from a turbid liquor return inlet pipe on the upper part of the pre-ash barrel through the return pipe under the action of a return pump.

As an improved technical scheme, the distance between the outlet center line of the return pipe and the bottom of the pre-ash barrel is 12-15cm, the diameter of the return pipe is 18-22cm, and the return amount of the blending liquid is 360-380m³/h。

As an improved technical scheme, a blending liquid obtained by stirring and mixing lime milk and preheated mother liquor through a pre-ash barrel enters a separator, turbid liquid separated by the separator flows back from a turbid liquid reflux inlet pipe at the upper part of the pre-ash barrel through a reflux pump to enter the interior of the pre-ash barrel, and supernatant separated by the separator enters a distillation tower.

As an improved technical scheme, the separator comprises a body made of carbon steel, the body comprises a straight barrel section and a conical barrel section which are integrally structured and mutually communicated, and the height ratio of the straight barrel section to the conical barrel section is 2: 3; a supernatant outlet is formed in the center of the top of the straight barrel section, a mixed liquid inlet pipe is arranged on one side of the upper part of the straight barrel section along the tangential direction of the barrel body, and the distance between the central line of the mixed liquid inlet pipe and the top of the straight barrel section is 40-45 cm; the bottom center of the conical barrel section is provided with a turbid liquid outlet, and the diameter of the mixed liquid inlet pipe, the diameter of the supernatant outlet and the diameter ratio of the turbid liquid outlet are 9:8: 4.

As an improved technical scheme, the reflux quantity of the turbid liquid is 360-380m³/h。

As an improved technical scheme, the pre-ash barrel comprises a barrel body, wherein a turbid liquid backflow inlet pipe is arranged on one side of the upper portion of the barrel body, the distance between the center line of the turbid liquid backflow inlet pipe and the top of the barrel body is 300-350cm, the distance between the center line of the turbid liquid backflow inlet pipe and the liquid level in the barrel body is 200-250cm, and the included angle between the center line of the turbid liquid backflow inlet pipe and the barrel wall on the side is 20-25 degrees.

As an improved technical scheme, a first gas inlet is arranged on one side of the upper part of a barrel body of the pre-ash barrel, a second gas inlet is arranged below the first gas inlet, a first manhole is arranged below the second gas inlet and close to the middle of the barrel body, a second manhole is arranged below the first manhole and close to one side of the bottom of the barrel body, and a mixed liquid outlet is arranged below the second manhole; a first preheating mother liquid inlet and a second preheating mother liquid inlet are arranged below the third manhole and close to the middle of the barrel, a lime milk inlet is arranged below the second preheating mother liquid inlet, and a fourth manhole is arranged below the third manhole; the inside of staving is equipped with agitating unit, agitating unit passes through motor drive.

As an improved technical scheme, the stirring device comprises a stirring shaft and a plurality of stirring rods which are arranged on the stirring shaft at equal intervals, and one end of the stirring shaft is connected with a motor.

As an improved technical scheme, the stirring device comprises a stirring shaft and a stirring frame arranged on the stirring shaft, wherein one end of the stirring shaft is connected with a motor, the stirring frame is U-shaped, and a plurality of connecting rods are arranged between the stirring shaft and the frame of the stirring frame.

As an improved technical scheme, the stirring device comprises a stirring shaft, one end of the stirring shaft is connected with a motor, the other end of the stirring shaft is provided with a stirring cage, and the stirring cage is composed of vertical rods and a steel belt which is transversely arranged between the vertical rods; wherein the montant is 2 groups, and two montants of every group symmetry each other set up, and 2 groups of montants pass through the link and are connected with the agitator shaft.

After the technical scheme is adopted, the invention has the beneficial effects that:

(1) the invention arranges a return pipe on one side of a pre-ash barrel close to the bottom of a barrel body or arranges a separator between the pre-ash barrel and a distillation tower (the blended liquid mixed by stirring lime milk and preheated mother liquor through the pre-ash barrel enters the separator along a blended liquid inlet pipe which is arranged along the tangent of the barrel body, the blended liquid rotates and flows down along the inner wall of the barrel body under the action of gravity, so that the clear liquid and the turbid liquid containing large particles can be better separated), the blended liquid (containing large particles) at the bottom in the pre-ash barrel and the turbid liquid at the bottom separated by the separator enter the pre-ash barrel from the turbid liquid return inlet pipe along a pipeline through a return pump, the returned blended liquid or turbid liquid contains a large amount of limestone and calcium oxide particles, and the calcium sulfate generated by reaction in the mixed material in the pre-ash barrel is attached to the surface of the large particles to form larger particles, the surface tension of the newly generated calcium sulfate crystal is eliminated, so that the newly generated calcium sulfate is not attached to the stirrer and the barrel wall, and the formation of scabs is avoided.

(2) After the turbid liquid containing large particles enters the pre-ash barrel, the back-flow scouring and the friction force are increased, so that scars attached to the surfaces of the stirrer and the barrel wall fall off.

(3) After the turbid liquid containing large particles enters the pre-ash barrel, the settling speed can be increased, so that newly generated calcium sulfate crystals are attached to the large particles to be quickly settled, and the calcium sulfate crystals are prevented from being accumulated in a main generation area and then being attached to a stirrer and the barrel wall to form scabs.

(4) The utilization efficiency of the lime milk is improved, large particles of the lime milk which are not completely reacted are returned to the pre-ash barrel to be reacted again, and the consumption of the lime milk is reduced.

Drawings

FIG. 1 is a process flow diagram of the present invention without the addition of a separator;

FIG. 2 is a flow diagram of the process of the present invention with the addition of a separator;

the system comprises a pre-lime barrel 1, a lime milk inlet 10, a preheated mother liquor inlet 11, a mixed liquid outlet 12, a turbid liquid reflux inlet pipe 13, a mixed liquid reflux pipe 14, a separator 2, a turbid liquid outlet 20, a supernatant outlet 21, a mixed liquid inlet pipe 22, a distillation tower 3 and a reflux pump 4.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail with reference to the following embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.