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Method and device for gasifying pulping black liquor and reclaiming directly causticized alkali

A technology of pulping black liquor and caustic soda, applied in the regeneration of lye, lime production, etc., can solve the problems of difficult temperature requirements, achieve the effects of simple and easy control, reduce dust content, and eliminate the risk of explosion in water

Inactive Publication Date: 2012-06-20
GUANGZHOU INST OF ENERGY CONVERSION - CHINESE ACAD OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Due to the high temperature requirements of the direct causticization reaction and the high melting point of titanate, it is difficult to apply the direct causticization technology to the current low-temperature fluidized bed gasification and high-temperature liquid slag entrained gasification.

Method used

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  • Method and device for gasifying pulping black liquor and reclaiming directly causticized alkali
  • Method and device for gasifying pulping black liquor and reclaiming directly causticized alkali

Examples

Experimental program
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Effect test

Embodiment 1

[0046] Such as figure 1 shown. From the evaporation section, the thick black liquor 21 with a solid content of more than 50% enters the black liquor batching tank 9, where the black liquor is mixed with a direct causticizing agent, and the direct causticizing agent can be TiO 2 . If the Na and K contained in the black liquor are all converted into Na according to the amount of their substances 2 CO 3 or Na 2 O, then TiO 2 with Na 2 The molar ratio of O substances should be controlled from 1 to 3, generally 1.25 to 1.3. TiO 2 It is an oxide that is insoluble in water and lye, so it is also insoluble in black liquor. The batching tank 9 must be equipped with a stirring device to maintain the uniformity and stability of the material. The stirring speed should generally not be lower than 50r / min.

[0047] In order to increase the reliability of pyrolysis furnace 1 operation, black liquor and TiO 2 The mixture should be preheated to a certain temperature before entering th...

Embodiment 2

[0054] Na 2 O 3TiO 2 with fresh TiO 2 have almost the same deCO 2 Ability to remove CO from carbonate at high temperature 2 and form new titanates such as 4Na 2 O·5TiO 2 , the temperature is controlled at 850-900°C. Although 4Na 2 O·5TiO 2 It cannot be hydrolyzed completely, but the main solid phase product of its hydrolysis is Na 2 O 3TiO 2 Can be reused, satisfying this point can form a closed cycle of causticizing agent, so it can replace the lime causticizing cycle. The TiO described in the previous example 2 The final product Na formed in the direct causticization process 2 O 3TiO 2 Become the direct causticizing cycle intermediate product of this embodiment.

[0055] Such as figure 1 As shown, the sulfate black liquor 21 from the evaporation section and the Na from the hydrolysis tank 7 2 O 3TiO 2 After being fully mixed in the black liquor batching tank 9, it is continuously transported to the atomizing nozzle 2, and various processes are carried out as ...

Embodiment 3

[0057] Because caustic soda straw pulp black liquor does not contain sulfur, the alkali recovery equipment using this process is relatively simple. There is no need to install a hydrogen sulfide absorption tower 6 in the treatment of crude synthesis gas, and the liquid output from the hydrolysis tank 7 is NaOH solution, which is directly used for cooking. Other aspects are not significantly different from the gasification and alkali recovery of sulfate black liquor.

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Abstract

The invention discloses a method and a device for gasifying black liquor under a direct causticization condition, which can be used for reclaiming alkali from black liquor by a sulfate process and a caustic soda process. The method comprises the following steps of: thermally decomposing the black liquor mixed with a directly causticizing agent into semi-coke, wherein the directly causticizing agent can be titanium dioxide or sodium trititanate; performing the reactions such as organic carbon gasification, removal of carbon dioxide of carbonate, sodium sulfate reduction and the like on the semi-coke through a gasification furnace by using water vapor as a gasification agent to generate oxygen-rich coarse synthesis gas containing a little amount of hydrogen sulfide, and reclaiming inorganicsubstances, namely sodium pentatitanate, of the black liquor in a solid state; and performing processes such as hydrogen sulfide absorption and the like on the coarse synthesis gas to form refined synthesis gas, hydrolyzing the sodium pentatitanate to generate sodium hydroxide, and recycling the sodium trititanate which cannot be continuously hydrolyzed. The invention also discloses the device adopted by the method. The method has the advantages of solid reclamation of pulping chemicals and the like, and greatly avoids high-temperature corrosion of carbonate smelt.

Description

technical field [0001] The invention relates to the technical field of pulping industry, in particular to a method and device for gasifying pulping black liquor and directly recovering caustic alkali. technical background [0002] The traditional black liquor treatment method in the pulping industry is a commonly used chemical recovery process. The core of this process is the recovery boiler, which is often called an alkali recovery boiler in China. The recovery boiler was invented by G.H. Tomlinson in the 1930s and subsequently became an important milestone in the development of the kraft pulping process. Although many improvements have been made in the recovery boiler over the years, the core technology has not changed, so its inherent defects always exist, such as low thermodynamic efficiency and the risk of explosion when the melt meets water. The application of black liquor gasification technology is expected to solve these problems. [0003] Chemical recovery is ofte...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): D21C11/04
CPCY02P40/40
Inventor 阴秀丽袁洪友吴创之周肇秋马隆龙
Owner GUANGZHOU INST OF ENERGY CONVERSION - CHINESE ACAD OF SCI