JPS5943183A - Method and apparatus for recovering soda from pulp waste liquor - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides improvements to pulp waste soda recovery methods and devices;
In particular, it concerns measures to streamline the causticization process for recovered chemicals.

Figure 1 shows the alkaline pulp production process.-4' 11!
' is a schematic explanatory diagram. Hereinafter, with reference to FIG. 1, a conventional alkaline pulp production method will be explained in Section 7.

In Fig. 1, 1 is a valve evaporator can, 2 is a blow tank for pulp material, 5 is an evaporator for concentrating liquid, and 4 is an 11V chemical circuit.

Boiler (hereinafter referred to as recovery boiler)-5 is a smelt dissolution tank, a 6-piece causticizing tank, a 7-piece rotary kiln, 8 is a white liquor tank, and a 9-piece electrostatic precipitator.

Chemicals for bulb cooking are supplied to the digester 1 or the causticizing tank 6, and the following are blow tank 2, evaporator 5, recovery boiler 4, smelt dissolving tank 5, causticizing tank 6-white liquor tank 8
The valves are circulated in the cooking chemical circulation system PLft in this order. The carbonate produced in the causticizing tank 6 is calcined in a tari kiln 7 to form calcium oxide, which is then converted to calcium oxide in the causticizing tank 6. y, Foreign items are scattered as dust in a part of the flue in the recovery boiler 4, but the
J' and A2 are collected by the dust generator 9, sent to the black liquor line 6/61, and sent to the first recovery boiler 4) for combustion. In the conventional method, the alkaline valve waste liquid is burned in the recovery boiler 4.The smelt produced here is dissolved in water in the smelt bath decomposition tank 5 to create a sodium carbonate aqueous solution. This carbonate of soda is then fed into the causticizing coffin 16 as C:a (0)i )2 (also (ζ
1 White 10 and TI are brought into contact with (1) and steamed into 15 of the following formula. ■It is causticized by caustic soda that is Ai in the product),
co3 +ea(]suy → 2NaOH4f8)(zu0゜Meanwhile, reconnaissance I'r, i 6 produced 7/, -Ca
The C03 is calcined in a rotary tank 7 (converted to CaO), evaporated with water to t-:a (0TI), and recycled to the causticizing tank 6.

Note: The disadvantage of the conventional method is that the causticizing tank 6 generates I~ (-゛old type 0. The amount of combustion used when firing the slurry kiln is large).

The present invention aims to save energy and recover chemicals in the calcination of the C03 slurry produced in the causticizing tank 6. 1' The purpose is 11v boiler valve) 1 liquid combustion 7Xtceac
o, ij<supply powder mainly containing -U ll'll
IIX Bo. 1 CaQ is calcined in the furnace once and 'Kl'r is formed in the furnace. Along with the smelt flowing down the wall ('(-11V Boise F' 7゛, IL's soda solution 1st eye and soda and-), Horikunumu Kaicho collection 1'' to 5/4 -That is the summary and 4) (1 so A
・、Ru.

As a result, CaC0 and powder 4' in the conventionally used ^1 carbonization unit fN'i' can be fed into the combustion section of the unfired waste recovery boiler. For example, a rotary kiln? You can save on fuel costs by eliminating the need for printing.

A first aspect of the present invention is to supply a powder containing carbonate calcyano, cate:l, to the valve waste liquid combustion section of the recovery boiler when performing spray combustion of valve waste liquid in a soda recovery boiler.
゛ [Calcium oxide is obtained in the recovery bowl, and the calcyano oxide calcined in the inner furnace flows down the furnace wall by the added gas supplied to the bottom of the furnace. Soda rd%' at the bottom of the recovery boiler along with smelt? 41 to the tank! Soda and) J Luciumke Recovery”-Kotoke Features and 1”-
The second invention O-1 includes a recovery boiler for spray-combusting valve waste liquid, a valve waste liquid combustion section V of the recovery boiler, A pressurized gas supply device is installed in the recovery boiler furnace (J'ifi) and a pressurized gas supply device is installed in the river. The method and apparatus of the present invention (i <? Suitable for 1+I, -c-effective for paper valve steaming, which is an energy-intensive industry (paper valve steaming)
Refer to the figure and do 7 Chigi IjJj theory + pJ.

As shown in the figure, there are 10 parts of the recovery boiler body.The lower part is sloped in a funnel shape and is formed to allow the smelt to flow down easily. I'm here. 11 is the boiler bank part connected to the smoke pipe, 12 is the pallet and waste liquid burner, and 1b and 14 are the primary and secondary air supplies 1], +5) and 2-co-2 mainly containing calcium carbonate. Powder containing, for example, limestone (ra+
;03, Fill the draw, ), )) (size', l
”V9CO,.

It is a supply port for etc. In addition, the above powder (・9j Valzo Vt
:Liquid supply system Vc addition II 1. , '7 is also good. +
56. ．． 1,,1'' installed at the bottom of the recovery boiler 10, -'I'(1,'i屓・1V11.1
7 is Filunso? +1 mountain area of Iq'i monk 16: Opening II-→Z, and so on.
1 (l is -l: i + t: Ng dissolving 'Hjl 161
””: Uqj r-: I J Rugoto <'lI+:
t＞'7 ”ca Jl, A:, fl 7i, t
jN output t7 pipe, 19 is the same white liquid extraction 'i::? I 1
1 or 1 yo 1^, l'1. , 't < 2X white liquid tank, 20 times 7 nights and evenings, ・'ri + /l1 (l J sailed white liquid supply pipe, 21 to 1'' - recorded ゛θ゛ζ 解 monk 1
The carbonic acid side and the IJ take-out pipe connected to the bottom of 6 are connected to the bottom.

22 Id times 11'X wheeler mJ7Enowhat+rIK+
X, 2 s B kt, slag, tungsten pole, 24 kiln furnace (, sloping layer 22 (Al
The accumulated calcium dioxide moves toward the arm slag tap hole 25, and cleaning gas (compressed air or water vapor) is supplied to prevent it from falling. In the 15 loaf composition, due to the effect of the invention, II
Q, l'1Jl-. Pulp waste liquid e-burning part-r' of the recovery boiler 10 has highly concentrated pulp waste liquid at the bottom of the furnace.
1) Primary and secondary air supply pipes supplied to the I1 furnace. Heated air supplied from '1-14
Burning c lt″1.:i melt (mainly, with tCOs
) f generation - (ru. At this time, as shown in the figure, the bottom of the furnace is tilted in the shape of a funnel to improve the flow of the wood smelt.

Furthermore, at the bottom of the furnace, a powder containing mainly calcium oxide, such as limestone CaCO, is injected into the furnace from the powder supply port 1. . Calcined in a furnace c CaC0,→Ca
O + Co, ) Sao + -7'c a Of direction -f on the bottom of the furnace. At the same time, 25 tubes of 34 tubes are allowed to flow down into the lower soda dissolving tank 16 using the step 34 and 25 tubes. In the melting @16, from the water supply pipe 1 to the tl
F) Smell in pre-supplied water) (Na2LJ)
3- <:*O) is dissolved and the following reaction occurs.

Na, C03-t-Ca, O+ H, O→ 2NaOH
-CtlCO3 In this way, make hJ a OH with the steamed product.

On the other hand, the NaO produced in the -1 tank 16 (soda solution)
From the white liquor take-out port 118 to the white liquor tank 19, the white liquor supply pipe 20 is sent to the pulp cooking chemical circulation system (see Figure 1). -)λLru.

In addition, 2/("-jiJ pressure 0,
is taken out from the calcium carbonate slurry takeout L121.

The present invention has the following effects! 4.2 is played) N is turned □) The method of the present invention is based on the method of the present invention:
1. Calcium carbonate is mainly used in the valve waste liquid combustion section of the ν boiler (tCi). The oxidizing power is supplied to the recovery boiler furnace (1).
Let it bake, and put it in the oven! ``Since 7+ temperature is increased to 1- to make it caustic, the fuel consumption is larger compared to the conventional method, and heating by 1m-tarigiron is not required, so fuel costs can be reduced significantly. There are advantages.

(b) Most of the oxidizing power fired in the furnace is smelt flowing down the furnace wall due to the 11-pressure gas directed toward the bottom of the furnace, and the soda-soluble M phase at the bottom of the recovery boiler. -・It was made to lead to j% of the melting point.7.
C80, which has good fluidity, can be easily flowed down to the soda dissolving tank together with 1N CO and smelt. e
The decomposition reaction of a e O is 890~9[] (at about 6C) where the reaction proceeds only with JII heat. -l can be done.

Naka) The present invention is installed in the valve waste liquid ejected and combusted.
In the recovery boiler, the valve of the first recovery boiler is arranged all the way around the waste liquid combustion section, and the first supply L1 for supplying the powder containing calcium carbonate and the bottom surface of the first recovery boiler furnace are arranged so as to be oriented toward the bottom surface F. Pressurized gas supply equipment installed
and recovery boiler r: *u [Since it has a soda dissolving tank for accelerated recovery of soda and calcium, it has the advantage of being able to eliminate the smelt dissolving tank, caustic boiler, and rotary kiln and reduce manufacturing costs compared to conventional equipment.

@ The furnace structure of the recovery boiler is almost the same as that of the alkaline valve hospital liquid recovery boiler, and has the advantage that the technological development elements are limited to a part of the bottom of the furnace.

[Brief explanation of the drawing]

Figure 1 shows the conventional alkali barno-made soil process.)
IF-sheet, and Figure 2 is the book > i, "1 light (hub z〃, and equipment shown, schematically k)...Sub-Agent 1) Mei-Fuku Agent Ryo Hagiwara - Chapter 1 Figure 9 Kazuo Wakasugi, Commissioner of the Japan Patent Office, dated February 1, 1981, 1. Indication of the case, Patent Application No. 14923j of 1983. 3. Relationship with the person making the amendment. Patent applicant 1. Place: Maru, Chiyoda-ku, Tokyo. 5) No. i”
``;, (62o) Mitsubishi Heavy Industries, Ltd. (Name: 杓υ Representative: Ya Kido 4 agents 11 Address: Toramon, Minato-ku, Tokyo -] Kawa'' No. 24-11) ``Details of the invention'' Contents of correction in column a of “Explanation”

Claims (2)

[Claims] (1) When pulp waste liquid is spray-combusted in a soda recovery boiler, powder containing mainly calcium carbonate is supplied to the pulp waste liquid combustion section of the recovery boiler, and calcyano-57 oxide is obtained in the recovery boiler furnace. A pulp waste soda recovery method characterized in that the calcined calcium oxide is guided to the soda dissolving tank at the bottom of the recovery boiler together with the smelt flowing down the furnace wall by pressurized gas supplied to the bottom of the furnace and the soda and calcium content Y are recovered. . (2) In a soda recovery boiler that sprays and burns valve waste liquid, each time an opening is made to the pulp waste liquid combustion section of the recovery boiler (
A supply port for powder mainly containing calcium carbonate is provided, a pressurized gas supply device is provided to direct toward the bottom of the recovery boiler, and a portion of soda and calcium is collected at the bottom of the recovery boiler. A valve waste liquid soda recovery device comprising a soda dissolving tank.