A method for utilizing waste heat of tail gas of continuous acidolysis of titanium dioxide by sulfuric acid method

Abstract

The application discloses the technical field of acidolysis tail gas treatment and discloses a method for utilizing waste heat of continuous acidolysis tail gas of titanium dioxide by sulfuric acid method, which comprises the following steps: the acidolysis tail gas is transported into a bag type dust collector through a pipeline to be subjected to bag type dust removal; the tail gas after the bag type dust removal is subjected to dry desulfurization in a desulfurizer, and the removed sulfur is transported to an acid making process to be subjected to acid making; the steam generated after the desulfurization is transported to a secondary heat exchanger to be subjected to heat exchange, and the steam condensate water generated after the heat exchange is subjected to heat exchange in a primary heat exchanger; the titanium liquid and waste acid are subjected to preheating in the primary heat exchanger by the steam condensate water, and the preheated titanium liquid and waste acid are subjected to heat exchange with the steam in the secondary heat exchanger, wherein the acidolysis tail gas is utilized, the titanium liquid and waste acid are subjected to heat treatment by the temperature of the acidolysis tail gas, and the utilization rate of the waste heat of the acidolysis tail gas is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of acidolysis tail gas treatment, in particular to a method for continuous utilization of waste heat of acidolysis tail gas in sulfuric acid method titanium white. BACKGROUND

[0002] The acidolysis tail gas is tail gas generated in the acidolysis process, and mainly contains a large amount of water vapor, acid mist, H2S, SO2 and the like in the tail gas, which causes serious pollution to the environment and needs to be treated before being discharged.

[0003] The existing acidolysis tail gas method is to transmit the acidolysis tail gas into a spray tower, spray lye in the spray tower to neutralize it, and then treat the tail gas treated by the spray tower by a Venturi spray method, and then directly discharge the tail gas treated by the Venturi spray into the air. The existing acidolysis tail gas only considers cooling, dust removal and tail gas desulfurization, and does not utilize the heat energy. The heat energy is wasted by mainly using water (alkali liquor) spray for cooling and desulfurization. SUMMARY

[0004] The present application aims to provide a method for continuous utilization of waste heat of acidolysis tail gas in sulfuric acid method titanium white, to solve the problem that the existing acidolysis tail gas only considers cooling, dust removal and tail gas desulfurization, and does not utilize the heat energy, mainly uses water (alkali liquor) spray for cooling and desulfurization, and the heat energy is wasted.

[0005] To achieve the above-mentioned purpose, the present application provides the following technical scheme: a method for continuous utilization of waste heat of acidolysis tail gas in sulfuric acid method titanium white, which comprises the following steps:

[0006] S1: the acidolysis tail gas is conveyed by a pipeline into a bag-type dust collector for bag-type dust removal;

[0007] S2: the tail gas after the bag-type dust removal is introduced into a desulfurizer for dry desulfurization, and the removed sulfur is conveyed to an acid making process for acid making;

[0008] S3: the steam generated after the desulfurization is conveyed to a secondary heat exchanger for heat exchange, and the steam condensate water generated after the heat exchange is introduced into a primary heat exchanger;

[0009] S4: the titanium liquid and waste acid are introduced into the primary heat exchanger for preheating by the steam condensate water, the preheated titanium liquid and waste acid are introduced into the secondary heat exchanger for heat exchange with the steam introduced into the secondary heat exchanger, the waste acid is concentrated by heat exchange in the secondary heat exchanger, the heat-exchanged titanium liquid is sent to a hydrolysis process for hydrolysis, and the concentrated waste acid is sent to an acidolysis process for acidolysis;

[0010] S5: The steam after heat exchange through the secondary heat exchanger enters into the primary heat exchanger, and then enters into the tail gas fan, and the steam after heat exchange through the primary heat exchanger is discharged from the chimney into the air through the tail gas fan.

[0011] Preferably, the temperature of the acidolysis tail gas is 160℃.

[0012] Preferably, the temperature of the steam after dry desulfurization is 120-130℃.

[0013] Preferably, the temperature of the steam is 80-86℃.

[0014] Preferably, the primary heat exchanger and the secondary heat exchanger are graphite heat exchangers or plate heat exchangers.

[0015] Preferably, the method further comprises an organic Rankine cycle generator, which is connected with the primary heat exchanger and the secondary heat exchanger through pipelines.

[0016] Compared with the prior art, the method has the advantages that the acidolysis tail gas is utilized, the titanium liquid and waste acid are heat treated through the temperature of the acidolysis tail gas, and the utilization rate of the acidolysis tail gas waste heat is improved. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 The method is a flowchart. DETAILED DESCRIPTION

[0018] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the protection scope of the present application.

[0019] The present application provides a method for utilizing the waste heat of continuous acidolysis tail gas of sulfuric acid method titanium white, which utilizes the acidolysis tail gas, heat treats the titanium liquid and waste acid through the temperature of the acidolysis tail gas, and improves the utilization rate of the acidolysis tail gas waste heat. Figure 1 The method for utilizing the waste heat of continuous acidolysis tail gas of sulfuric acid method titanium white comprises the following steps:

[0020] S1: The acidolysis tail gas at 160℃ is transported into a bag-type dust collector through a pipeline for bag-type dust removal.

[0021] S2: The tail gas after bag type dust removal enters into the desulfurizer to carry out dry desulfurization, and the desulfurization of the acidolysis tail gas is carried out by using activated carbon or iron oxide, and sulfur can be recycled for sulfuric acid production, and the tail gas after dry desulfurization produces 120-130 DEG C steam;

[0022] S3: The steam produced after desulfurization is transported to the secondary heat exchanger for heat exchange, and the 80-86 DEG C steam condensate water produced after heat exchange enters the primary heat exchanger;

[0023] S4: The titanium liquid and waste acid enter the primary heat exchanger and are preheated by steam condensate water, and the preheated titanium liquid and waste acid enter the secondary heat exchanger and are heat exchanged with the steam entering the secondary heat exchanger, and the waste acid is concentrated in the secondary heat exchanger, and the heat-exchanged titanium liquid is hydrolyzed, and the concentrated waste acid is acidolysis, and the primary heat exchanger and the secondary heat exchanger are graphite heat exchangers or plate heat exchangers, and the waste heat of the tail gas is used to preheat the hydrolysis concentrated titanium liquid or replace the steam for waste acid concentration, and the existing acidolysis tail gas waste heat is mostly cooled by water spraying, and the circulating water needs to be cooled by a cooling tower, and the application utilizes the heat energy of the tail gas, and the steam does not need to be cooled, which not only utilizes the heat energy, but also reduces water consumption and cooling tower power consumption, improves the utilization rate of acidolysis tail gas waste heat, and also includes an organic Rankine cycle generator, which is connected with the primary heat exchanger and the secondary heat exchanger through pipelines, and generates electricity by using waste heat;

[0024] S5: The steam after heat exchange in the secondary heat exchanger enters the primary heat exchanger and is discharged into the air from the chimney through the tail gas fan.

[0025] Example 1

[0026] The method for utilizing the waste heat of the continuous acidolysis tail gas of the sulfuric acid method titanium white comprises the following steps:

[0027] S1: The 160 DEG C acidolysis tail gas is transported to the bag type dust collector through the pipeline for bag type dust removal;

[0028] S2: The tail gas after bag type dust removal enters into the desulfurizer to carry out dry desulfurization, and the desulfurization of the acidolysis tail gas is carried out by using activated carbon or iron oxide, and sulfur can be recycled for sulfuric acid production, and the tail gas after dry desulfurization produces 120 DEG C steam;

[0029] S3: The steam produced after desulfurization is transported to the secondary heat exchanger for heat exchange, and the 80 DEG C steam condensate water produced after heat exchange enters the primary heat exchanger;

[0030] S4: The titanium liquid and waste acid enter the first heat exchanger and are preheated by steam condensate water. The preheated titanium liquid and waste acid enter the second heat exchanger and are heat-exchanged with steam entering the second heat exchanger. The waste acid is concentrated by heat exchange in the second heat exchanger. The heat-exchanged titanium liquid goes to the hydrolysis process for hydrolysis. The concentrated waste acid goes to the acidolysis process for acidolysis. The first heat exchanger and the second heat exchanger are graphite heat exchangers or plate heat exchangers. The method further comprises an organic Rankine cycle generator connected to the first heat exchanger and the second heat exchanger through pipelines, which generates electricity by utilizing waste heat.

[0031] S5: The steam heat-exchanged by the second heat exchanger enters the first heat exchanger and then enters the tail gas fan. The steam heat-exchanged by the first heat exchanger is discharged from the chimney into the air by the tail gas fan.

[0032] Example 2

[0033] The method for utilizing waste heat of continuous acidolysis tail gas of sulfuric acid method titanium dioxide comprises the following steps:

[0034] S1: The acidolysis tail gas at 160℃ is transported to the bag-type dust collector through a pipeline for bag-type dust collection.

[0035] S2: The tail gas after bag-type dust collection enters the desulfurizer for dry desulfurization. The removed sulfur is transported to the acid-making process for acid making. The tail gas after dry desulfurization generates steam at 110℃.

[0036] S3: The steam after desulfurization is transported to the second heat exchanger for heat exchange. The 83℃ steam condensate water generated after heat exchange enters the first heat exchanger.

[0037] S4: The titanium liquid and waste acid enter the first heat exchanger and are preheated by steam condensate water. The preheated titanium liquid and waste acid enter the second heat exchanger and are heat-exchanged with steam entering the second heat exchanger. The waste acid is concentrated by heat exchange in the second heat exchanger. The heat-exchanged titanium liquid goes to the hydrolysis process for hydrolysis. The concentrated waste acid goes to the acidolysis process for acidolysis. The first heat exchanger and the second heat exchanger are graphite heat exchangers or plate heat exchangers. The method further comprises an organic Rankine cycle generator connected to the first heat exchanger and the second heat exchanger through pipelines, which generates electricity by utilizing waste heat.

[0038] S5: The steam heat-exchanged by the second heat exchanger enters the first heat exchanger and then enters the tail gas fan. The steam heat-exchanged by the first heat exchanger is discharged from the chimney into the air by the tail gas fan.

[0039] Example 3

[0040] The method for utilizing waste heat of continuous acidolysis tail gas of sulfuric acid method titanium dioxide comprises the following steps:

[0041] S1: the acidolysis tail gas at 160 DEG C is transported into a bag filter through a pipeline for bag filtration;

[0042] S2: the tail gas after bag filtration is transported into a desulfurizer for dry desulfurization, and the removed sulfur is transported to an acid making process for acid making, and the tail gas after dry desulfurization generates 130 DEG C steam;

[0043] S3: the steam generated after desulfurization is transported to a secondary heat exchanger for heat exchange, and the 86 DEG C steam condensate water generated after heat exchange is transported into a primary heat exchanger;

[0044] S4: the titanium liquid and waste acid are transported into the primary heat exchanger for preheating by steam condensate water, the preheated titanium liquid and waste acid are transported into the secondary heat exchanger for heat exchange with the steam transported into the secondary heat exchanger, the waste acid is concentrated by heat exchange in the secondary heat exchanger, the heat exchanged titanium liquid is transported to a hydrolysis process for hydrolysis, and the concentrated waste acid is transported to an acidolysis process for acidolysis, the primary heat exchanger and the secondary heat exchanger are graphite heat exchangers or plate heat exchangers, and an organic Rankine cycle generator is further included, which is connected with the primary heat exchanger and the secondary heat exchanger through pipelines respectively, and generates power by using waste heat;

[0045] S5: the steam after heat exchange in the secondary heat exchanger is transported into the primary heat exchanger for heat exchange, and then is transported into a tail gas fan, and the steam after heat exchange in the primary heat exchanger is discharged from a chimney into the air by the tail gas fan.

[0046] Although the present application has been described with reference to the embodiments above, various improvements can be made and equivalent substitutions can be made to the components without departing from the scope of the present application. In particular, each feature in the disclosed embodiments of the present application can be combined with any other feature in any manner without structural conflicts, and the combinations are not exhaustively described in the specification only for the purpose of omitting pages and saving resources. Therefore, the present application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A method for utilizing waste heat from the continuous acidolysis tail gas of titanium dioxide produced by the sulfuric acid process, characterized in that: The method for utilizing the waste heat from the continuous acid hydrolysis tail gas of titanium dioxide produced by the sulfuric acid process includes the following steps: S1: The acid hydrolysis tail gas is transported through pipelines to a bag filter for bag dust removal; S2: The exhaust gas after passing through the bag filter enters the desulfurizer for dry desulfurization, and the removed sulfur is transported to the acid production process for acid production. S3: The steam generated after desulfurization is transported to the secondary heat exchanger for heat exchange, and the steam condensate generated after heat exchange enters the primary heat exchanger. S4: The titanium liquid and waste acid enter the primary heat exchanger and are preheated by steam condensate. The preheated titanium liquid and waste acid enter the secondary heat exchanger and exchange heat with the steam entering the secondary heat exchanger. The waste acid is concentrated in the secondary heat exchanger. The titanium liquid after heat exchange goes to the hydrolysis process for hydrolysis. The concentrated waste acid goes to the acidolysis process for acidolysis. S5: After heat exchange in the secondary heat exchanger, the steam enters the primary heat exchanger for further heat exchange and then enters the exhaust gas fan. The exhaust gas fan then discharges the steam from the chimney into the air.

2. The method for utilizing waste heat from the continuous acidolysis tail gas of titanium dioxide production using the sulfuric acid process according to claim 1, characterized in that: The temperature of the acidolysis tail gas is 160℃.

3. The method for utilizing waste heat from the continuous acidolysis tail gas of titanium dioxide production via sulfuric acid process according to claim 2, characterized in that: The steam temperature after dry desulfurization is 120-130℃.

4. The method for utilizing waste heat from the continuous acidolysis tail gas of sulfuric acid titanium dioxide according to claim 3, characterized in that: The temperature of the steam condensate is 80-86℃.

5. The method for utilizing waste heat from the continuous acidolysis tail gas of sulfuric acid titanium dioxide according to claim 4, characterized in that: The primary and secondary heat exchangers are either graphite heat exchangers or plate heat exchangers.

6. The method for utilizing waste heat from the continuous acidolysis tail gas of sulfuric acid titanium dioxide according to claim 5, characterized in that: It also includes an organic Rankine cycle generator, which is connected to the primary heat exchanger and the secondary heat exchanger via pipes.

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