JPS59184293A - Treatment of low grade coal - Google Patents

Abstract

PURPOSE:To prepare dehydrated coal in briquet at a low cost, by crushing and classifying low grade coal, mixing dehydrated coal obtained by non-evaporative heating of granulated coal with a heavy tar obtained by dry distillation of surplus dust coal and forming the mixture into briquets. CONSTITUTION:Low grade coal is fed into a crushing and classifying unit 1 and granulated coal is separated from surplus dust coal. The granulated coal is introduced into a non-evaporative heating and dehydrating device 4 for non evaporative heating and dehydration to produce dehydrated coal, while the surplus dust coal is led into a dry sidtillation devie 6 for distillation into dry distillation gas, light tar, heavy tar, dry distillation char, etc. The heavy tar is mixed with the dehydrated coal and the mixture is formed in a briquetting unit 7 to produce dehydrated coal in briquets. Organic components contained in waste water of dehydration can be removed by adsorption by brining the waste water into contact with the dry distillation char.

Description

[Detailed Description of the Invention] This invention relates to a method for treating low-grade coal that has a degree of coalification of 1 degree higher than V-1, such as lignite, lignite, and sub-#' eddy coal, and contains a large amount of moisture and volatile matter. be.

Although low-grade coal, such as lignite, has large reserves in the concession area, it has high moisture content, high volatile content, and strong activity, so some of it is used in the mountains. do not have. −
For example, lignite from Taizhou contains more than 60% moisture,
If this coal is used as a fuel as it is, the transport efficiency and thermal efficiency will be significantly lower.1 In order to use these brown coals, it is necessary to dehydrate them in advance at the base of the mountain to reduce the water content to about 20% or less.

Conventionally, as a dehydration method for this purpose, there has been a method of evaporating the contained water using hot gas such as flash drying, but this evaporation water method has been used in the first step of drying. , a large amount of heat must be supplied as the latent heat of vaporization, which is extremely disadvantageous in terms of cost, and if the dehydrated product is a fine powder, there are problems such as dust generation - spontaneous combustion and exposure to coal dust. It is not suitable for dehydration and drying.

On the other hand, in the non-evaporative heating dehydration method known as the 7 Reissner method, raw lignite is charged into an autoclave, and saturated steam is directly heated and pressurized by introducing hot water into it.
The moisture in the lignite is dehydrated under non-evaporation ambient air by lowering the surface tension and decomposing the functional groups.It can be dehydrated efficiently without loss due to the latent heat of evaporation. . However, in this method, the raw material lignite is crushed and classified in the tube that generates the predicted wastewater. tI
Pulverized coal is derived during the RI handling process. This pulverized coal is a surplus method that is not suitable for non-evaporative dehydration. In other words, non-evaporative heating dehydration technology for lignite using saturated steam or hot water is
Although it is suitable for lumpy lignite, it is difficult to treat powdered lignite below 5-l Q M7JI (-).If the inverted π lumpy coal becomes too coarse, it will take a long time to heat, resulting in poor processing efficiency. Raw coal to be subjected to non-evaporative heating and dehydration is usually subjected to particle size adjustment as a pretreatment.
Pulverized coal is derived. . In addition, it is inevitable that pulverized coal will be generated due to π destruction during coal mining and handling.
Excess pulverized coal separated from granular coal of about l 5 Q'rrrrrr is conventionally dehydrated separately using drying techniques such as ventilation drying to produce product coal, or directly boiled at 11N without dehydration. The high-pressure steam 1k supplied to the system generates hot water and serves as a heated steam source or hot water source for non-evaporative heating and dehydration. In addition, dehydrated coal obtained by non-evaporative dehydration has disadvantages such as low bulk density and high transportation costs because it is porous with water and organic matter removed.

This method was developed in view of the above points, and is a method of crushing and classifying low-grade coal such as lignite, lignite, and sub-bituminous coal to separate it into sized coal and excess pulverized coal. Dehydrated coal is obtained by evaporation heating and dehydration, and the excess pulverized coal is carbonized to separate it into carbonized gas/light tar and heavy tar/carbonized char.
The object of the present invention is to provide a method for processing low-grade coal, which is mixed with heavy tar and glacial coal, and then pregetted to produce Brichera I dehydrated coal.

The Keisukeki invention involves bringing carbonized char into contact with dehydrated wastewater produced by non-evaporative dehydration to stratify the organic components in the wastewater.
Providing a treatment method for low-rank coal to be removed? 1 purpose is binding.

Furthermore, the organic components in the wastewater are adsorbed and removed by bringing the final 4id-carbonized char into contact with the dehydrated wastewater produced by the evaporative dehydration π, and then the adsorption-treated tansui is separated into solid-liquid to form a water-synapsing carbonized char. The purpose of the present invention is to provide a method for treating low-rank coal, in which the supernatant liquid and fO separation 12, 1,000 ml of water carbonized char is π-combusted with the carbonized scum and 1 ridged tar to serve as part of the heat source for the non-evaporative dehydration step. It is said that

In the non-evaporative dehydration method, as mentioned above, the dehydrated water from raw lignite, hot water for heating, and condensed water from steam are
Discharged as wastewater. This wastewater is mixed with lignite fine grains, and due to the dissolution of various components from lignite, the wastewater reaches 100'OOp'p.
'm S S (fiJra solid 1t ACOD C
Chemical oxygen Win), B 0 around 7000 ppm
1) Contains (biological oxygen distillation publication), I) 3 to H
It is 5. Should wastewater with such high SS-high COL) and high BOD values be discharged into a VC system that discharges it into a natural water system? t 6G
K: Some kind of purification treatment must be applied before cultivation; water regulations must be met.

Techniques commonly applied to the treatment of 1 liter of water with a relatively high concentration of contaminants include physical treatments such as gravity sedimentation and filtration, chemical treatments such as coagulation and sedimentation, activated sludge method, and rotational p-treatment. There are biological treatments that utilize extraction methods, sprinkled bed methods, packed bed methods, and anaerobic treatment methods.

However, in VC, which removes a large amount of SS contained in water by physical treatment of lignite non-evaporative heating dehydrated water, industrially it must be done by centrifugation because the SS is fine. However, the C0D = BOD of clear water immediately after treatment still shows a high value, and the secondary treatment J! 11 is essential. In addition, if the S content in wastewater is accelerated by coagulation and sedimentation,
Almost all of the S, COD, and BOD must be added to the sludge trap, which can collect more than 50% of the COD and BOD. There was also the problem that there was a large amount of waste and the burden of disposal was high. Sarapi
Stratification treatment has conventionally been carried out as an advanced treatment using expensive granular or powdered activated carbon1 to remove minute flame components. ,
It is judged that it is inappropriate to use expensive activated carbon because of the raw residue.

In this way, lignite non-evaporative dehydrated wastewater has extremely low levels of heavy metals and iq-toxic substances such as cyanide, but on the other hand, the absolute amount of wastewater is large and the concentrations of SS, COD, and BOD are high, so it cannot be treated with normal treatment methods or their combinations. The non-evaporative dehydration method loses its superiority due to the increased operating cost, especially the cost of added chemicals, and the increased burden of return water treatment costs, leading to the problem of not being able to supply a cheap energy source and a single product charcoal. be.

The second invention and the third invention 8rl bring the carbonized char obtained by carbonizing excess pulverized coal into contact with the waste water, and utilize the excellent absorption ability of the carbonized char to reduce CO in the h'c water.
The secret is to remove elements such as D.

Hereinafter, the Kinoi F114 will be explained with reference to the drawing f. Figure 1 shows an example of the Kienori method. The raw coal is fed into the primary sieve 2 of a 6-liter crushing and classifying device using a conveyor such as a humbair, and is crushed by a crusher 3 into coarse particles with a χ1γ diameter of about 150M or larger, which are then fed into a secondary sieve 4π together with the small and medium particles. - where non-evaporative heating dehydration π suitable 5 ~
The granulated coal is divided into granulated coal with a particle size of about 150 m and pulverized coal with a particle size of about 571 rM or less.The sized coal is loaded into a non-evaporative heating dehydration device 5 consisting of an autoclave, etc. At a temperature of 250°C, a loaf of saturated steam at a pressure equivalent to this temperature is dehydrated with hot water. For example, a loaf of raw coal with a moisture content of about 65% is dehydrated to a moisture content of about 20%, and is stored as dehydrated coal. As a result of this treatment, from the non-evaporative heating dehydration device a5, - for example, 0.56 tcg of dehydration from lignite and 0.28 to 0.451 tcg of condensed water from steam, which is a heating source, per 1.lcg of raw coal. (A total of about 7 liters of water is discharged as wastewater.
Approximately D7000 p p m - COD l 0000'
p pm approx.-5SIO approx. 000 ppm, pH 3-5
That's about it.

The surplus pulverized coal is sent to a carbonization device 6 where it is carbonized and separated into the following components: carbon dioxide, carbon dioxide tar, carbon dioxide tar, and carbon dioxide. The notation is ``ice coal'', and the density is extremely small because the machine is removed and porous. For this purpose, the dehydrated coal and the fragrant tar obtained from the carbonization f are introduced into a mixing/briquetting device f577, mixed and briquette-ized, and then mixed and briquette-ized. : 'Obtain the product briquette dehydrated coal with a large degree of IFs. That is, the modified tar is used as a briquetting aid to fill the pores of the porous dehydrated coal, and is also used as an interlayer.

On the other hand, the carbonized char and the dehydrated water are brought into contact with each other in a contact tank 8π, and the dissolved organic components in the water are converted into the carbonized char,
After adsorption fv, 4f min, dry distillation char in tank 10.
The second clear liquid is separated into two clear liquids, and the second clear liquid is sent to the secondary treatment equipment.
The water-dried char and the HFL-described gas/light tar are sent to a combustion device 11 such as a boiler and burned, and become part of the non-evaporative dehydration device 50. Compared to pulverized coal as it is, carbonized coal has a much greater ability to remove particles in t9fi water per suction pot, and can achieve the target of removing suction pots with a small addition of 1i4. . There is an advantage that the amount of water in the C contact tank 8 and the separation tank 10 is reduced, and the dry Ml char after 15g water treatment has good drainage properties. 1klfl (1, Heat of J1 can be recovered by mixed combustion with E-IYl gas and light tar after drying with water, making it useless as a heat source for non-evaporative heating dehydration port 1)
You can do it - The following is a summary of the examples of trial and error that people have done.
! I] do it. Yaroon pulverized coal is carbonized in nitrogen gas at 840"C for 1 hour to produce carbonized char (f4) - This carbonization char and Yaroon sized coal are combined with dehydrated dead water (COD1170).
p p m ) were stirred and mixed at 4 rpm for 2 hours, filtered through a filter paper, and separated into the filtrate and sludge.

The water content h1 of the sludge is 36.1%, and the relationship between the added carbonized char concentration and the filtrate (ODi!
It was close.

A stainless steel reactor with an inner diameter of 45,717 Il was filled with yarn pulverized coal, and nitrogen gas was added to
/ min and heated to 900'C for 1 hour and carbonized to obtain this 1k) fruit charcoal with a yield of 01g char/da raw coal (total moisture 70%). did it.

As described above, the final IJ11 is an extremely effective way to utilize the excess pulverized coal generated by non-evaporative dehydration of lignite and other low-weight pulverized coal. can be,
It has the effect of being able to dispose of bottom-grade coal at a low cost.

[Brief explanation of the drawing]

FIG. 1 shows a systematic explanation of an example of a device for carrying out the method of End 4! Figures 1-1 and 2 are graphs showing the results of a wastewater adsorption test using Yarun charcoal carbonization char.

Claims (1)

[Scope of Claims] 1. Low-rank coal is crushed and classified into approximately granular coal and surplus pulverized coal, and the charcoal is heated and dehydrated without evaporation to produce deicing coal, and the surplus pulverized coal is carbonized. A low-grade coal characterized in that it is divided into carbonized gas, light cool, heavy cool, and carbonized char, and then mixed with IJfi dehydration method of first grade tar, and then converted into briquettes to make ``C product briquette dehydrated coal.'' Processing method. 2. Low-grade coal is crushed and classified into roughly granular coal and surplus pulverized coal, and sized coal is produced (evaporation heating and dehydration is performed to obtain dehydrated coal, and at the same time, carbonization is performed to obtain carbonized scum.・Contact the light tar, military taru carbonization char with the separation 1-5 carbonization char and the dehydrated 1 water produced by non-evaporative dehydration to remove component A] 1 in J'16 water as :lB. A method for processing low-grade coal characterized by mixing heavy tar with 01 (notation number 01) glacial coal and making it into priquettes to produce the product Grikent deicing coal.・Separate charcoal and surplus pulverized coal, and obtain deicing coal by non-evaporative heating and dehydration of the granulated coal, and carbonize the surplus pulverized coal to produce carbonized gas/light tar.
Separate into heavy cool carbonized char, bring the carbonized char into contact with dehydrated wastewater produced by non-evaporative dehydration to adsorb all of the organic components in the charged water, and after 12 kg, adsorption treatment i1! The water is pulverized to solidify and separated into pith, carbonized water char, and supernatant water, and the carbonized water char is combusted together with the carbonized gas and 100% tar to be used as part of the heat source for the non-evaporative dehydration process. , On the other hand, after combining the heavy coal with rJQ glacial coal, it is converted into briquent to produce the product briquent dehydrated coal jX-'+,'i
, a method for processing low-rank coal with characteristics,