WO2005080875A1

WO2005080875A1 - Circulating fluidized bed burning method for waste liquor of paper making, hide manufacture, printing and dyeing

Info

Publication number: WO2005080875A1
Application number: PCT/CN2005/000059
Authority: WO
Inventors: Dawei Zhang
Original assignee: Shenyang David International Machinery & Electric Equipment Co., Ltd.
Priority date: 2004-01-15
Filing date: 2005-01-14
Publication date: 2005-09-01
Also published as: CN1558143A; CN100408918C

Abstract

A treatment method for waste liquor of paper making, hide manufacture, printing and dyeing uses a circulating fluidized bed burning method. Said method includes a filtered coal mud preparing step, a waste liquor and coal slurry preparing step, and a waste liquor and coal slurry burning step. In the filtered coal mud preparing step, coal active carbon and calcium lime is used as adsorbing and filtering material to treat the waste liquor by adsorbing depositing and filtering, to prepare filtered coal mud containing combustible substance from the waste liquor. In the waste liquor and coal slurry preparing step, pulverized coal, water and dispersing is added in the filtered coal mud, sludge and waste liquor, then stirred, then added in stabilizing agent, to prepare waste liquor and coal slurry for boiler. In the waste liquor and coal slurry burning step, quartz sand and limestone is used as fluidized medium in the chamber of the circulating fluidized bed boiler, and the waste liquor and coal slurry is fed into the circulating fluidized bed boiler to burn to produce steam and hot water. The treatment method uses circulating fluidized floating burning method to treat and utilize black liquor from production.

Description

Method for treating waste liquid of papermaking, tanning, printing and dyeing industry by circulating fluidized combustion method

Technical field

The invention relates to a method for treating sludge, waste liquid, cooking liquid (black liquid, red liquid), tail liquid and waste water produced in an industrial production process, and particularly relates to a circulating fluidized combustion method for treating papermaking, making The method of leather, printing and dyeing industry waste liquid and wastewater can treat and comprehensively utilize its tail liquid and sewage. Background technique

At present, there are certain deficiencies in the treatment methods of cooking liquor (black liquor, red liquor), waste fluid, tail liquor, sludge and other treatment methods produced in the papermaking, tanning, printing and dyeing industries, especially the treatment of black liquor in paper mills. Because of the worldwide difficulties, some paper mills had to stop production because pollution could not be controlled.

At present, China's papermaking pollution control technology is mainly divided into four categories:

(1) Alkali recovery technology. This technology has large investment, high operating costs, and production scale constraints. Paper mills below 20,000 tons / year cannot be used. About 55% of the already-built alkali recovery production line is not put into use.

(2) Physical, chemical and biochemical technologies, which use various chemical and physical methods such as precipitation, flocculation, and air flotation, plus activated sludge aeration or anaerobic fermentation, etc. for biochemical treatment. Such technologies have a large investment and occupy a large area. Large, high operating costs, and poor pollution control.

(3) Evaporation and concentration technology. This method converts black liquor into products by evaporation, concentration, and drying. However, because the market for the converted products has not been developed, the technology cannot be used. There are also companies that spray and inject black liquor into The boiler is burned out. Due to the complicated process and high processing cost, the technology cannot be promoted.

(4) At present, domestic enterprises using recycled waste paper produce a large amount of black mud. At present, most of the posts have no ship black turning 亍 processing and utilization, only buried from the legs, 5 t, Peng H ^ has been processed, and In fact, this method of covering up the border has actually caused long-term serious pollution to the surrounding environment, soil and underground.

Taken together, the current typical black liquor and wastewater pollution treatment processes have the following problems:

1. Large investment, high processing costs, and small and medium-sized paper mills cannot afford it. China's paper industry is developed under the severe shortage of funds and the difficult supply of wood raw materials. It is mainly based on the development of small grass pulp and paper mills. These enterprises are small in scale, low in product quality, poor in equipment and personnel, and profitable. Low, high pollution production coefficient, pollution control is limited by treatment costs. 2. The technical reliability of the completed environmental protection and treatment facilities is poor, and normal operation cannot be guaranteed, and it is more difficult to ensure compliance with emissions. As a result, enterprises have wasted their input funds.

3. The biochemical treatment process cannot run normally, and it is generally maintained by adding flocculants.

4. Pollution control lacks comprehensive utilization value for enterprises and cannot bring direct benefits to enterprises. Enterprises are passively governed and lack initiative. Summary of the invention

Aiming at the general problems of the existing environmental protection technology of waste liquid and waste water pollution treatment in the papermaking, tanning, printing and dyeing industries, the present invention provides a method for treating waste liquid from papermaking, tanning, printing and dyeing industries by using a circulating fluidized combustion method. The waste liquid, waste water and sludge produced in the process are treated and comprehensively utilized.

The technical solution of the present invention to solve the technical problems and achieve the objectives of the present invention is to provide a method for treating waste water from papermaking, tanning, and printing and dyeing industries by using a circulating fluidized combustion method, including the following steps:

a. Coal filter mud preparation step, that is, the use of coal-based activated carbon and quicklime as adsorption and filter materials, the wastewater produced in the production process is subjected to adsorption, precipitation, and filtration treatment to produce a combustible substance that contains intermediate wastewater Slime

b. Waste liquid coal slurry preparation step, that is, adding pulverized coal and dispersant to the prepared coal sludge, stirring, and then adding a stabilizer to prepare waste liquid coal slurry for use as boiler fuel;

c Waste liquid coal slurry combustion step, that is, the prepared waste liquid coal slurry is transported to a circulating fluidized bed boiler for combustion to produce steam or hot water. The furnace of the circulating fluidized bed boiler includes quartz sand and limestone. Fluidizing medium.

In the waste liquid coal slurry preparation step of the above-mentioned circulating fluidized combustion method for treating papermaking, tanning, and printing and dyeing industry waste liquid, the weight ratio of the coal powder and water in the waste liquid coal slurry is 7: 3.

According to another aspect of the present invention, a method for treating waste liquid of papermaking, tanning, and printing and dyeing industries by using a circulating fluidized combustion method is provided, including the following steps:

a waste liquid coal slurry preparation step, that is, adding granular coal to waste liquid containing combustible substances, ball milling in a ball mill into a mixed coal slurry with a particle diameter of 50-150 μm, and then adding a stabilizer to stir Into a waste liquid coal slurry; b. A waste liquid coal slurry combustion step, that is, transporting the prepared waste liquid coal slurry to a circulating fluidized bed boiler for combustion to produce steam or hot water, wherein the furnace of the circulating fluidized bed boiler has Including fluidized media composed of quartz sand and limestone.

According to a further aspect of the present invention, a circulating fluidized combustion method is provided for treating papermaking, tanning, and printing. The method for dyeing industrial waste liquid includes the following steps:

a waste liquid coal paddle preparation step, that is, coal powder and waste liquid in a weight ratio of 6: 4 and a stabilizer are sent to a pulping tank for mixing and stirring to produce waste liquid coal slurry;

b. The waste liquid coal slurry combustion step, that is, the prepared waste liquid coal slurry is transferred to a circulating fluidized bed boiler for combustion to produce steam or hot water. The furnace of the circulating fluidized bed boiler includes quartz sand and limestone. Fluidizing medium.

According to a still further aspect of the present invention, a method for treating papermaking, tanning, and printing and dyeing industrial waste liquids by using a circulating fluidized combustion method is provided, including the following steps-a. A step for preparing liquid coal slurry, that is, washing coal particles and black mud for papermaking , Waste water and dispersant, according to the washed coal particles, black mud and waste water in a ratio of 6: 2: 2, added to a ball mill for wet grinding, grind the washed coal particles into a mixed slurry with a particle diameter of 50-100 μm, and send it to the pulping tank. Add stabilizer to make waste liquid coal slurry;

In the above-mentioned circulating fluidized combustion method for treating the waste liquid coal slurry combustion method of the papermaking, tanning, printing and dyeing industry waste liquid, the method further includes using a screw pump to supply the waste liquid coal slurry from the middle or top of the circulating fluidized bed boiler. Pulp injection. If the circulating fluidized bed boiler only uses waste liquid coal slurry as fuel, the spiral coal feeding equipment is eliminated. If the boiler uses coal and waste liquid coal slurry as fuel, the spiral coal feeder is retained.

In the above-mentioned method for treating the waste liquid of papermaking, tanning, printing and dyeing industry by the circulating fluidized combustion method, the injection pressure of the waste liquid coal slurry is 0.3Mpa.

In the above-mentioned method for treating the waste liquid of papermaking, tanning, printing and dyeing industry by the circulating fluidized combustion method, the combustion temperature of the circulating fluidized bed boiler is controlled at 850-950 ° C.

In the above-mentioned cyclic fluidized combustion method for treating the waste liquid coal slurry combustion method of the papermaking, tanning, and printing and dyeing industry waste liquid, the method further includes placing unburned coal and garbage particles carried out by the hot flue gas in all places. The combustion fluid outlet of the circulating fluidized bed boiler or the fly ash separator at the rear is separated and captured, and then sent back to the dense phase area of the combustion chamber for circulating combustion through a return device provided at the lower part of the separator.

The dust removal rate of circulating flow boilers can reach 99.9%, and the concentration of soot in the side gas is <80mgm ³ . The S (¾ emission concentration in the flue gas is <100mg m ³ , the NOx concentration is less than 150mg m ³ , and the manganese blackness of the flue gas is <1, which is in accordance with national standards for atmospheric environmental protection.

Circulating fluidized bed boilers can use hot water boilers, low pressure steam boilers or high and medium pressure steam boilers. It can be used by enterprises to produce steam, and can also be used for heating or power generation, forming the integration of wastewater treatment, steam use and power generation, in order to save a lot of energy costs and wastewater treatment costs.

The fly ash collected by the dust collector after the waste liquid coal propeller is combusted can be used. After the waste liquid coal slurry is suspended and cleaned and burned in a circulating fluidized bed boiler, the fly ash generated is collected by the dust collector and transported by a sealed conveying device to the In a sealed ash bin, after reaching a certain amount, it is transported away by pulverized coal, which saves the environment from flying, and the fly ash has a high comprehensive utilization value. BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a process flow diagram of using a circulating fluidized combustion method to treat papermaking, tanning, printing and dyeing industrial wastewater, and preparing waste liquid coal slurry and burning the waste liquid coal slurry.

FIG. 2 is a process flow diagram of using the circulating fluidized combustion method to treat papermaking, tanning, and printing and dyeing industrial waste liquid (cooking liquid), sludge, and black mud to prepare waste liquid coal slurry and burn the waste liquid coal slurry. Best Mode for Carrying Out the Invention Preferred embodiments of the present invention will be described below with reference to the drawings. The invention mainly consists of the following two parts: 1. Preparation of waste liquid coal slurry

According to the different raw materials, it can be divided into the following three schemes:

(1) Wastewater is filtered, adsorbed, and settled to produce waste liquid coal slurry with effective energy substances. The process flow is shown in Figure 1. According to this scheme, a circulating fluidized combustion method is used to treat papermaking and tanning. A method for printing and dyeing industrial waste liquid, including the following steps: The coal filtering mud preparation step is made by using coal activated carbon and quicklime as adsorption and filtering materials, and absorbing, precipitating and filtering the wastewater generated in the production process. The coal sludge containing combustible substances in the waste water; the waste liquid coal slurry preparation step, that is, adding pulverized coal and dispersant to the prepared coal sludge, stirring, and then adding a stabilizer to make it to be used as a boiler The waste liquid coal paddle of fuel; the waste liquid coal paddle combustion step, that is, the prepared waste liquid coal slurry is sent to a circulating fluidized bed boiler for combustion to produce steam or hot water, and the furnace of the circulating fluidized bed boiler includes Fluidized medium consisting of quartz sand and limestone.

Specifically, pulverized coal, coal-based activated carbon, and quicklime are added to the filter tank 3, and a multi-stage filter tank 3 can be constructed as required. The pulverized coal, coal-based activated carbon, and quicklime added to the filter tank 3 have strong adsorption and flocculation properties as filter materials. After the wastewater flows through the filter tank 3 (or multi-stage filtration), the wastewater contains Most of the fine fibers, lignin and other organic substances are filtered out and adsorbed in the filter material such as pulverized coal in the filter tank 3, and the remainder A part of the fine coal powder exists in the filtered water in the form of colloid, and flows into the sedimentation tank 6, and the sedimentation effect is generated by flocculation. The fine short fibers, lignin and other organic substances in the wastewater are settled together with the coal powder, and the upper part of the sedimentation tank The water flows into the treatment tank, and the coal slurry in the lower part of the sedimentation tank is transported to the bottom flow storage tank 5 of the wastewater sedimentation tank through the screw pump 14-1 in the lower part of the sedimentation tank.

After a period of time, the filter material such as coal powder in the filter pool is used to filter and adsorb a large amount of organic matter and suspended matter, to a certain extent, it reaches a saturated state, and does not play an adsorption role, and then becomes a coal filter mud, which saturates the filter pool 3 Coal sludge is transported to the bottom sedimentation tank 5 of the wastewater sedimentation tank through the screw pump 14-1, and the bottom sedimentation tank 5 of the wastewater sedimentation tank is used as the secondary sedimentation tank. The water in the bottom sedimentation tank 5 of the wastewater sedimentation tank is discharged to the treatment tank 4. The coal sludge in the lower part of the bottom flow storage tank 5 of the wastewater sedimentation tank is transported to the pulping tank 7 by the screw pump 14-2.

The filter material in the filter tank 3 contains a certain amount of coal-based activated carbon and calcium hydroxide, and at the same time as filtering, it also plays a role in denitrification, dephosphorization, decolorization, and deodorization of wastewater.

The coal filter sludge sent to the pulping tank 7 must be tested before each batch is added to check the water content, etc., and then a certain amount of coal powder or wastewater is added in proportion so that the coal to water ratio is 7: 3 Right and left, add the dispersant to start the stirrer on the top of the pulping tank, stir, then add the stabilizer to continue stirring, and then cut through the shearing conveying pump 14-3, mature, and then transport it to the waste liquid coal slurry storage tank 15 Medium storage.

The water in the treatment tank 4 is pumped to the original wastewater treatment equipment of the enterprise for further treatment, and then returned to the production system for use.

A small test is required before production to determine the proportion or quantity of various ingredients. The waste liquid coal slurry in the storage tank 15 is periodically stirred as required.

(2) Making waste liquid coal slurry with waste liquid (cooking liquid)

The process flow chart is shown in FIG. 2. The equipment of the combustion part of the waste liquid coal slurry is the same as that in FIG. 1, and the same reference numerals are used.

It can be divided into two different production methods according to the use of coal-a. The waste liquid coal slurry is produced by washing coal particles. According to this technical solution, a method for treating the waste liquid of papermaking, tanning, and printing and dyeing by using a circulating fluidized combustion method is provided. The method includes the following steps: a waste liquid coal slurry preparation step, that is, adding granular organic coal to the waste liquid containing organic substances, ball milling in a ball mill into a mixed coal slurry having a particle diameter of 50-150 μm, and then adding a stabilizer to stir The waste liquid coal slurry is burned. The waste liquid coal slurry is burned, that is, the prepared waste liquid coal slurry is sent to a circulating fluidized bed boiler for combustion to produce steam or hot water. The furnace of the circulating fluidized bed boiler includes Fluidized medium consisting of quartz sand and limestone.

Specifically, the washed coal particles are crushed and weighed by a crusher 19, and then sent to a ball mill 20 through a conveying device, and The waste liquid in the waste liquid storage tank 8 is sent to the ball mill 20 through the screw pump 14-2 in proportion, and the coal particles are ground to a coal slurry with a particle size of 50 to 100 μm, and then the screw pump 14'-2 It is transported to the pulping tank 7 and added with a stabilizer for stirring. After being sheared and matured by a shearing conveying pump 14-3, it is transported to a waste liquid coal slurry storage tank 15 for storage.

b,

According to this technical solution, a method for treating waste liquid of papermaking, tanning, printing and dyeing industry by using a circulating fluidized combustion method is provided, including the following steps: a waste liquid coal slurry preparation step, that is, a coal powder and a waste liquid are 6 by weight: 4 ratio and stabilizer are sent to the pulping tank for mixing and stirring to produce waste liquid coal slurry; the waste liquid coal slurry combustion step is to transport the prepared waste liquid coal slurry to a circulating fluidized bed boiler for combustion to produce steam or Hot water, in which the fluidized medium consisting of quartz sand and limestone is contained in the hearth of a circulating fluidized bed boiler.

Specifically, as shown in FIG. 2, the equipment such as the crusher 19 and the ball mill 20 must be removed, and the pulverized coal silo (not shown), the waste liquid storage tank 17 and the additive tank 9 should be directly transferred to the pulping tank 7. , The pulverized coal and the waste liquid in the waste liquid storage tank 8 'are proportionally sent to the pulping tank 7 through the conveying equipment for stirring, and then the stabilized IJ conveyed by the ^^ force «9' is added,« 3? « ί ^ ΐ4, -3 cut, rn j, mmm \ y ^^.

Before the production of each batch of waste liquid coal slurry, the coal powder and waste liquid must be tested and a small test must be performed to determine the proportion of coal powder, waste liquid and additives. The waste liquid coal slurry in the waste liquid tank 15 'must be used as required Stir regularly.

(3) Making waste liquid coal slurry with sludge and black mud

According to the different coal used, it can be divided into two different production methods:

a. The process flow is also shown in FIG. 2. Black mud (sludge) coal slurry is produced by washing coal particles. According to this technical solution, a method for treating the waste liquid of papermaking, tanning, and printing and dyeing by circulating fluidized combustion is provided. The method includes the following steps: a step of preparing waste liquid coal slurry, that is, washing coal particles and black mud of papermaking, waste water, and dispersant; adding the washed coal particles, black mud, and waste water to a ball mill in a ratio of 6: 2: 2; The granule is ground into a mixed slurry with a particle diameter of 50-100 μm, and then sent to a pulping tank to add a stabilizer to prepare a waste liquid coal slurry. The waste liquid coal slurry combustion step is to transport the prepared waste liquid coal slurry to a circulating stream. A fluidized bed boiler is used for combustion to produce steam or hot water. A furnace of a circulating fluidized bed boiler includes a fluidized medium composed of quartz sand and limestone.

Specifically, the washed coal particles are crushed and weighed by the crusher 19, and then sent to the ball mill 20 through the conveying equipment, and the black mud (sludge) is fed to the ball mill 20 through the screw pump 14'-2, and the waste water and dispersant are proportionally added. After grinding the coal particles into coal paddles with a particle size of 50 — 100 μ πm, they are sent to the pulping tank 7 ′ by the screw pump 14 ′ -2, and the stabilizer is stirred into the mouth, and then cut through Wi ^ l4,- 3 After shearing and aging, send to storage tank 15 for storage.

b. The process of making black mud (sludge) waste liquid coal slurry using pulverized coal is also shown in Figure 2, but the equipment such as crusher 19, ball mill 20, etc. must be removed. The pulverized coal silo (not shown) black mud storage tank 8 'and additive tank 9' are directly transferred to the pulping tank 7 ', and the black mud (sludge) in the pulverized coal and black mud storage tank 8' is passed through Screw pump 14'-2, wastewater The dispersant delivered from the additive tank 9 'is added to the pulping tank 7' according to the required ratio and stirred, and then the stabilizer is added to continue stirring, and then sheared ^^ 14'-3 after shearing and curing, and then transported to the storage Store in tank 15 '.

Before the production of each batch of black mud (sludge) coal slurry, the coal or coal powder, black mud (sludge) must be tested, and small tests should be performed to determine the coal or coal powder, black mud (sludge), wastewater, and additives. proportion. The waste liquid coal slurry made from black mud in the storage tank 15 'must be periodically stirred as required.

Combustion of waste liquid coal slurry

In order to apply waste liquid coal slurry made from waste water, waste liquid (black liquor), black mud, etc. as fuel, the present invention modifies the circulating fluidized bed boiler 1.

At present, circulating fluidized bed boilers at home and abroad all use dry pulverized coal as fuel, and a screw conveyor is used at the lower part of the boiler to send coal into the furnace. The circulating fluidized bed boiler 1 for burning waste liquid coal slurry is based on the original boiler design, and a waste liquid coal slurry supply port is installed at the top or middle of the boiler. If the circulating fluidized bed boiler 1 only uses waste liquid coal slurry as fuel, then The auger coal feeding equipment is abolished. If the boiler uses coal and waste liquid coal slurry as fuel, the auger coal feeder is retained.

The circulating fluidized bed boiler 1 of the waste liquid coal slurry is ignited by hot air flow. After the diesel is atomized by the ignition gun, it is burned in the pre-combustion cylinder. Air, heated high-temperature air enters the fluidized bed material layer through the air distribution plate. When the bed material is heated above 450 ° C, a small amount of waste liquid coal slurry is added to the circulating fluidized bed boiler 1. At this time, the furnace The temperature rises quickly. When the temperature in the circulating fluidized bed boiler 1 reaches 600 ° C, the amount of paddle supply can be gradually increased. The furnace temperature rises quickly, and the waste liquid coal slurry has been burned normally. At this time, the oil supply is stopped and the pre-heating is cut off. The combustion chamber completes the ignition and increases the supply of waste liquid coal slurry. »The fans 11 and induced draft fans 13 are adjusted to the air volume required for normal negative boating.

mmp \ m- m m., large and medium-sized boilers (35 tons 29MW ¾ ± power) in the middle, with two ports, e «ifAm middle, / boiler top, mm ^ uses the height of the boiler to speed up The moisture in the waste ¾ ^ is forwarded to i ^ wf, and the fire is debated.

The waste liquid coal slurry is directly sent from the storage tank 15 to the circulating fluidized bed boiler 1 through the screw slurry pump 12 at a pressure of about 0.3 MPa. After entering the circulating fluidized bed boiler 1 through the slurry supply port, the waste liquid coal slurry becomes Drop-shaped, drop-shaped waste liquid coal slurry is in the furnace. It is turned into finer particles due to the fluidized hot air flow in the furnace. It is tumbling and falling down in the furnace at the temperature of 850-950 ° C. During the falling process, The droplets are heated, decomposed and started to burn, and then poured into a fluidized bed composed of quartz sand and limestone. During the continued heating of the hot fluidized bed material, the precipitation of moisture and volatiles is quickly completed, and the fire and combustion Coke is burned, and the fine particles of granular waste liquid coal slurry mass further disintegrated in the fluidized state are taken out of the dense phase zone by the hot flue gas, enter the suspension chamber to continue burning, and there is a fly at the exit or rear of the combustion chamber. The ash separation and return device, the media material carried out by the hot flue gas and the large unburned particles are separated and captured by the separator, and returned to the dense phase area of the combustion chamber through the return device provided at the bottom of the separator for cyclic combustion. , The combustion efficiency is 98%.

The waste liquid coal is burned in the furnace at 850-95CTC at low temperature, which effectively inhibits the generation of thermal NOx during the combustion process. Because quartz sand and limestone are added as media materials in the furnace, limestone is decomposed at high temperature to generate CaO and waste liquid coal. The S0 ₂ formed after the sulfur in the pulverized coal in the slurry is combusted to generate CaS0 ₄ . The response is:

S0 ₂ + CaO + l / 20 ₂ ― CaS0 ₄

The emission of so ₂ in the flue gas is suppressed, and direct desulfurization in the circulating fluidized bed boiler 1 is achieved. The particle size of the limestone (desulfurizing agent) added to the circulating fluidized bed boiler 1 is selected from about 1-2 mm, and the calcium / ^ molar ratio is 1.5-2.5 when the desulfurization efficiency of 85% -95% is reached. Flammable organic materials such as lignin and hemicellulose contained in the waste liquid are converted into heat energy after being burned in the furnace. Other materials such as alkali generate sodium salts, sodium calcium and other materials during the combustion process and are mixed in the fly ash and discharged.

The circulating fluidized bed boiler 1 contains exhausted fly ash in the flue gas, which is collected by an electrostatic precipitator or a bag precipitator 2. The dust removal rate can reach 99.9%, and the smoke concentration in the gas is <80mg½ ³ . In the flue gas, S (¾ ¾½¾g <100mg / m ³ , NOx fiber concentration <150mg m ³ , smoke manganese blackness <1, which is the national standard for environmental protection requirements.

The circulating fluidized bed boiler 1 can be a hot water boiler, a low pressure steam boiler or a high or medium pressure steam boiler. The produced steam can be used by enterprises to produce steam, and it can also be used for heating or power generation, forming a wastewater treatment, steam and power integration. It saves enterprises a lot of energy costs, waste water treatment costs, and increases revenue. Every 1 ton of black liquor burned in the paper industry (the calorific value in the black liquor of papermaking is 8.37-10.04MJ / kg) is equivalent to saving 0.28 ~ 0.34 tons of standard coal.

The fly ash collected by the dust collector 2 after the waste liquid coal slurry is combusted can be used. After the waste liquid coal slurry is burned by the circulating fluidized bed boiler 1, the fly ash generated is collected by the dust collector 2 and transported by a sealed conveying device. In the sealed ash bin 5, after reaching a certain amount, it is transported by pulverized coal, which completely saves the environmental pollution of the flying ash, and the flying ash has very high comprehensive utilization value. There are two main sheds:

a. Fly ash is gelatinous and contains CaS0 _4. It is a substitute for slag and gypsum needed to make cement. It lacks sufficient slag resources. It is a raw material for making cement. It can be made into 325 with 50% each of cement clinker. # Cement, fly ash with high CaS0 ₄ content can make special cement and expansion agent.

b. Because the waste liquid coal slurry contains a large amount of alkali, lignin, glycan, calcium salts and the like, when burning in a furnace at 850 ~ 950 ° C, the above substances are converted into sodium salts, calcium salts, nitrogen, calcium phosphate High-active materials such as high-active materials are discharged together with fly ash. Fly ash containing high-active materials such as sodium salt, calcium salt, nitrogen, and calcium phosphate is not only a good base for organic fertilizers, but also can be used as an acid soil improver.

Applications

Taking a straw pulp paper mill with an annual output of 15,000 tons as an example, 100 tons of black liquor are discharged every day. The black liquor produced in the production process is used for treatment and comprehensive utilization.

^ A 75 small circulation ½ ^ waste ¾ «^ ¾ boiler, Datongfa i¾it 29.3MJ / kg, 6% ash, pulverized coal with a particle size of 50-100 μm, according to pulverized coal: black liquor = 6: 4 ratio After passing through the metering device, it is input to the pulping tank 7. The agitator is installed on the pulping tank 7 and has a double spiral belt structure. Its rotation speed is M = 5-50 _r / min and the peripheral linear speed is 2 m / s. Because the black liquor acts as a dispersant, No need to add dispersant, after stirring, mn ^ m, mm, then ^ cut, m / s, ^, its solid ^ i65-7o%, moisture

35—30%. The waste liquid coal slurry is pumped into a circulating fluidized bed steam boiler with a screw pump. The boiler burns 10.5 tons of waste liquid coal slurry per hour, and produces 75 tons per hour (the pressure is 1.6Mpa—3.82Mpa, temperature 240—450 ° C). For use in paper mills. The flue gas after combustion is discharged by the electrostatic precipitator.

Although some preferred embodiments of the present invention have been illustrated and described, the special iSffl and exemplary «examples of the present invention have also been illustrated and discussed to form a basis for various inventions. Many are possible within the scope of the invention. However, those skilled in the art will understand that these embodiments can be changed without departing from the principle and essence of the present invention, and the scope of protection is limited to the claims of the present invention and their equivalents.

Claims

Rights request

1. A method for treating waste liquid from papermaking, tanning, and printing and dyeing industries by using a circulating fluidized combustion method, including the following steps:

a. Coal filter sludge preparation step, that is, the use of coal activated carbon and quicklime as adsorption and filter materials, the waste water produced in the production process is subjected to adsorption, precipitation, filtration treatment to produce coal containing combustible substances in wastewater Filter mud

b. Waste liquid coal slurry preparation step, that is, adding pulverized coal and dispersant to the prepared coal filter sludge, sludge, waste liquid, stirring, and then adding a stabilizer to make waste liquid coal used as boiler fuel Pulp

2. A method for treating waste water from papermaking, tanning, and printing and dyeing industries by the circulating fluidized combustion method according to claim 1, wherein:

In the waste liquid coal slurry preparation step, the weight ratio of coal powder and water in the waste liquid coal slurry is 7: 3.

3. A method for treating waste liquid of papermaking, tanning, printing and dyeing industry by using circulating fluidized combustion method, including the following steps:

a waste liquid coal slurry preparation step, that is, adding granular coal to waste liquid containing combustible substances, ball milling in a ball mill into a mixed coal slurry with a particle diameter of 50-150 μm, and then adding a stabilizer to stir Into waste liquid coal slurry;

4. A method for treating waste liquid of papermaking, tanning, printing and dyeing industry by circulating fluidized combustion method, including the following steps-a. Waste liquid coal slurry preparation step, that is, coal powder and waste liquid in a weight ratio of 6: 4 Proportion and stabilizer are sent to the pulping tank for mixing and stirring to make waste liquid coal paddles;

5. A method for treating waste liquid of papermaking, tanning, printing and dyeing industry by using circulating fluidized combustion method, including the following: Steps:

a waste liquid coal slurry preparation step, that is, washing coal particles and papermaking black mud, waste water and dispersant, according to the washing coal particles, black mud and waste water are added to a ball mill for wet grinding at a ratio of 6: 2: 2, and the washed coal particles are ground into particles The mixed slurry with a diameter of 50-100 μm is sent to a pulping tank to add a stabilizer to make a waste liquid coal slurry;

6. A method for treating waste water from papermaking, tanning, and printing and dyeing industry by the circulating fluidized combustion method according to any one of claims 1, 3, 4, and 5,

In the step of burning the waste liquid coal slurry, the method further includes injecting the waste liquid coal slurry from a slurry supply port in the middle or top of the circulating fluidized bed boiler by using a screw pump. If the circulating fluidized bed boiler only uses waste liquid coal slurry as fuel, then the spiral coal feeding equipment is eliminated. If the boiler uses coal and waste liquid coal slurry as fuel, the spiral coal feeder is retained.

7. A method for treating waste water from papermaking, tanning, and printing and dyeing industry by the circulating fluidized combustion method according to any one of claims 1, 3, 4, and 5,

The injection pressure of the waste liquid coal slurry is 0.3 MPa.

8. The method for treating waste liquid from papermaking, tanning, printing and dyeing industry by the circulating fluidized combustion method according to claim 6, wherein the combustion temperature of the circulating fluidized bed boiler is controlled at 850-950 ° C.

9. The method for treating waste liquid from papermaking, tanning, and printing and dyeing industry by the circulating fluidized combustion method according to claim 7, wherein in the step of burning the waste liquid coal slurry, the method further comprises unburned exhausted by hot flue gas. The coal and garbage particles are separated and captured by the fly ash separator at the exit of the combustion chamber of the circulating fluidized bed boiler or at the rear, and then sent back to the dense phase area of the combustion chamber for circulating combustion through the return device provided at the lower part of the separator. .