CN102363930A

CN102363930A - Method for preparing active carbon during alkali recovery of papermaking black liquor

Info

Publication number: CN102363930A
Application number: CN2011101495205A
Authority: CN
Inventors: 葛培锦; 陈嘉川
Original assignee: Shandong Institute of Light Industry
Current assignee: Shandong Institute of Light Industry
Priority date: 2011-06-07
Filing date: 2011-06-07
Publication date: 2012-02-29
Anticipated expiration: 2031-06-07
Also published as: CN102363930B

Abstract

The invention discloses a method for preparing active carbon during the alkali recovery of papermaking black liquor. The method comprises the following steps of: mixing papermaking black liquor with wheat straw powder, cotton straw powder and corn stalk powder, soaking for 10-30 hours, putting into an activating oven, heating to 500-900 DEG C at the heating rate of 5-20 DEG C/min in the anaerobic state for pyrolyzing for 1-4 hours; bleaching an activated product with distilled water, and drying to obtain active carbon; and recovering alkali from the bleaching liquid, and causticizing to obtain alkali for pulping. The methylene blue adsorption value of the prepared active carbon is 4-9 mg/0.1g, and the active carbon can be used for treating waste water in a papermaking factory and has a good effect; and in the preparing process of the active carbon, no waste water or waste gas is discharged. The problem of treatment of papermaking black liquor can be solved, and the cost for papermaking waste water treatment can be lowered by using the prepared active carbon. The method belongs to the technical fields of pulping and papermaking.

Description

A kind of black liquid alkali reclaims and prepares process of active carbon simultaneously

Technical field:

The invention belongs to the pulp and paper technology field

Background technology:

People were once being perplexed in the environmental pollution that paper-making industry is brought for a long time.In the paper waste, black liquor is the major pollution source.Black liquid directly is discharged in the ocean, river, can cause local waters eutrophication, destroys original ecological balance.It therefore and back the bad reputation of contaminated environment.So-called black liquid is exactly being used for after the cellulose of papermaking extract to separate remaining alkaline black liquor in the plant.Black liquid mainly is made up of lignin and two kinds of compositions of hemicellulose.These two kinds of compositions and cellulosic function class seemingly, they support the cell membrane of plant together.Yet lignin and hemicellulose but can not show a candle to the such length of cellulose cell and have toughness, thereby are considered to papermaking waste material for a long time.The recycling of black liquid mainly contains following method: 1, Silvola recovery: traditional alkali recovery technology adopts: concentrate-burning-causticization process, thereby reach the purpose that reclaims alkali and recycle.Large-scale wood pulp papermaking factory alkali recovery is to reach 90%, and non-wood raw pulp factory (paddy and wheat grass, reed, sugarcane bagasse etc.) alkali recovery can reach more than 70%.The high load capacity that adopts alkali to reclaim can to reduce black liquor greatly pollutes, and BOD can reduce 80%～85%, can reclaim the heat energy chemicals increase economic benefit that reduces cost in addition.The advantage of this method is: the organic matter in the black liquor produces steam through burning and supplies the our factory to use, and does not have the market sale problem; Can reduce the pollutional load of full factory about 80%; Recyclable caustic soda more than 50% is the technology of pollution control more completely.For middle-size and small-size straw pulp enterprise, there is certain deficiency in this method: project investment, operating cost are high, produce the above pulp mill of slurry 1.7 ten thousand t per year and can realize the meagre profit operation; Wheat straw black liquor caloric value is low, viscosity is big, silicon content is high, makes that the alkali cost recovery is high, alkali recovery is low, operation easier is big, and technical process such as causticization, burning still need be improved, otherwise can't normally move.2, acid-precipitation method: will extract black liquor after Microfilter is removed fiber fines, and get into the lignin seperator that is added with acid solution, control pH value is separated out lignin and is become lignin products through heating, filter-press dehydration.This method makes the CODCr clearance reach 80%, and the SS clearance is about 85%, and chroma removal rate reaches 95%, and the lignin rate of recovery is about 80%, and dying load for the reduction organic matter has remarkable effect.The advantage of the method is: technical process is simple, invests lessly, reclaims lignin when cutting down organic matter and dye load.Have a series of deficiencies simultaneously: technical equipment corrosion is serious, the more sad filter of lignin, dehydration; Raffinate after handling on the technology can not reach discharge standard, and is acid, needs further to handle; Must reduce economically and use sour cost, there is the market problem in lignin products simultaneously.3, coagulant sedimentation: after the black liquor acidifying, add the flocculant coagulating sedimentation, after the Separation of Solid and Liquid, the sediment burning that acts as a fuel, filtrating is back to slurrying workshop section through the adsorption filtration rear section again, and all the other enter middle-stage wastewater.This method initial investment is lower, is applicable to the little paper mill of producing per year below ten thousand tons, but has more deficiency: handle not thoroughly, the BOD5 handling rate is merely about 20%; The sludge quantity that produces is big, dehydration is difficult, it is difficult to handle, and actual is a kind of method of pollution transportation; Operating cost is to the flocculant Price Sensitive, and running cost is higher throughout the year.

Black liquid prepares the active carbon present situation

At present domesticly carry out black liquid to prepare the situation of active carbon following:

Zhang Yubing ^[1], adopt the hydrochloric acid acid-precipitation method from black liquid, to extract lignin in the research.The lignin that is extracted is crushed to carbonized material and adds a certain amount of ferrocene behind the certain particle size as catalyst after certain temperature charing.With steam as activator, the regular hour of activation at a certain temperature, produce mesopore activated carbon, middle porosity is all greater than 55%.The road chess ^[2], carry out the research of the following aspects: 1. the research of softwood black liquor, straw pulp black liquor lignin extraction, preparation active carbon, inquired into the methylene blue adsorption capacity and the yield that prepare active carbon emphatically, obtained optimum process condition through orthogonal experiment; 2. the filtered fluid to the deposition lignin has carried out flocculation treatment, has obtained having the product of certain industrial value, and the filtered fluid after the flocculation treatment is expected to qualified discharge.Tan Fei ^[3], having carried out black liquor is the Primary Study that activator prepares active carbon: its method is that carbonization, activation two-phase method prepare active carbon.Wu Kaijin ^[4], carried out the experimental study of alkaline pulping black liquor preparing active carbon, employing be that black liquor mixes with wood chip, carbonization, the two-phase method that adds the activation of alkali activator prepares active carbon.

Summary of the invention:

The present invention relates to black liquid with after barley seeding food, cotton stalk powder, milled powders of cornstalk mix; After the impregnation process 10～30 hours, put into activation furnace, under anaerobic condition, be warming up to 500～900 ℃ and carry out pyrolysis; Omnidistance 1～4 hour, heating rate was 5～20 ℃/min; Activation products promptly obtain active carbon after with distilled water rinsing, drying; The both recyclable utilization of alkali after causticization, can be used as slurrying and uses alkali in the rinsing liquid.The present invention prepares the methylenum careuleum adsorptive value of active carbon at 4～9mg/0.1g, can be used for the wastewater treatment in paper mill and respond well; The present invention prepares in the active carbon process, no waste water, toxic emission.The present invention can solve the handling problems of black liquid, and the active carbon of preparation can reduce the paper waste processing cost.The present invention is that carbonization, an activation method prepare active carbon, reclaims alkali simultaneously; In carbonization, activation process, do not add activator in addition.

Description of drawings

Accompanying drawing is seen in the patent production procedure.

The specific embodiment

Patent of the present invention belongs to laboratory small test invention, does not pass through the intermediate industrial test.Therefore, the specific embodiment of the present invention is to carry out the intermediate industrial test, confirms that alkaline process chemical pulping black liquor prepares the production line of active carbon.

List of references

[1] Zhang Yubing, by the research that black liquid is produced mesopore activated carbon, Wuhan University Of Technology's Master's thesis [D], 2004,5.

[2] road chess, lignin prepares active carbon in the black liquor of pulp making, Northeast Forestry University's master thesis [D], 2005,6.

[3] Tan Fei, black liquor are the Primary Study [J] that activator prepares active carbon, Guangdong chemical industry, 2009,12-13.

[4] Wu Kaijin, the experimental study of alkaline pulping black liquor preparing active carbon [J], Fujian forestry science and technology, 2004,9,50-53.

Claims

1. a black liquid alkali reclaims and prepares process of active carbon simultaneously: relate to black liquid with after barley seeding food, cotton stalk powder, milled powders of cornstalk mix; After the impregnation process 10～30 hours; Put into activation furnace; Under anaerobic condition, be warming up to 500～900 ℃ and carry out pyrolysis, omnidistance 1～4 hour, heating rate was 5～20 ℃/min; Activation products promptly obtain active carbon after with distilled water rinsing, drying; The both recyclable utilization of alkali after causticization, can be used as slurrying and uses alkali in the rinsing liquid.

2. according to the said method of claim 1; Its key technology is with after barley seeding food, cotton stalk powder, milled powders of cornstalk mix with black liquid; After the impregnation process 10～30 hours, put into activation furnace, under anaerobic condition, be warming up to 500～900 ℃ and carry out pyrolysis; Omnidistance 1～4 hour, heating rate was 5～20 ℃/min; Activation products obtain active carbon after with distilled water rinsing, drying; Alkali is recycled in the rinsing liquid, after causticization, can be used as slurrying and uses alkali.The present invention is that carbonization, an activation method prepare active carbon; In carbonization, activation process, do not add activator in addition.