US1462576A - Coking of coal - Google Patents

Description

M 2.4, 3923- Ml-62,576

S. R ILL-INGW'ORTH COKlNG OF COAL Filed Aug. 29 1921 Patented July 243,, 110233.

UNHTEE STATES PATENT EHEWART ROY ILLINGWOETH, 0F BRYNFEDWEN, ENGLAND, ASSKGHOE T0 ILMIUG WORTH CAWONIZATION COMPANY, LIMITED, 0F MANCHESTEE J, ENGLAND.

0031376 035' COAL.

Application filed August 29,10fil.

To all whom it may concern:

Be it known that I, STEWART Ror TLLINowon'rn, a subject of the King of Great Britain, residing at Brynfedwen, Radyr, Glamorganshire, England, have invented new and useful Improvements in the Coking of Goal, of which the following is a speci cation.

This'invention relates to the production of various types of coke and is an improvement on the process described in the specification of our former application No.

448,871, now Patent No. 1,422,269, July 11, 1922.

The majority of coals, particularly the highly bituminous coals when carbonized at low temperatures namely temperatures up to 600 C. give soft porous products, which readily disintegrate with handling, and durin transport. In order to overcome this di culty various means have been suggested, in the main these methods have depended on mechanical compression of the charge, either by virtue of some special type of furnace, or at some stage after discharge therefrom, the addition of pitch, binders and the briquetting of the mass carbonized at low temperatures, and subsequent carbonization of this mass at higher temperatures has been advocated.

By the present invention I am able without the use of compression, the addition of binders or other means to produce at low temperatures dense hard fuel concurrent with the production of excellent yields of bye products such as oils and ammonia. This dense hard fuel has all the physical characteristics of metallurgical coke, and can be converted into the latter by heating the product formed at low temperatures (say under 600 C.) to higher temperatures up to about 900 C.1000 C.

My process comprises the following opera tions:

Firstly preheating the .coal'to obtain a productof the nature required for the second operation.

Secondly crushing if necessary this product and carbonizing the product at temperatures not exceeding 600 C. but preferably not exceeding 500 C. This opera tion is designated as the formation of coke Qerial No. 400,763.

structure since in this operation the resinic matter in the residue is wholly destroyed as such, and when this has taken place the mass cannot again be brought into a plastic state by heat, that is the texture of the product cannot undergo appreciable change. The product at this stage is smokeless fuel:

Thirdly, coking of the product of the second operation at temperatures above 600 C. If true coke (i. e. a coke of low volatile content). is desired, the product from the second operation is passed as soon as all the bye-products have been evolved to an oven maintained at any temperature above 600 C. in order to eliminate the desired amount of volatile matter from the smokeless fuel; at 900 C. the product loses all volatile matter.

The preheating operation depends on the nature of the coal, firstly the coal must contain the requisite quantity of resinic matter to cement the coal into coke. Tn the specification of in previous patent application No. 448,871 have shown that the resinic matter in coal is of varying degrees of sta bility, and that associated with it are vari- Qus types of non-cementing material ({5 cellulosic, etc.) which is also of varying degrees of stability. Now by the employment of suitable temperatures it is possible to eliminate from a coal certain portions of these constituents and to leave a residue which contains a more homogenous type of resinic matter (i. e. the resinic matter in the residue is decomposed between short limits of temperature) further this resinic matter is associated with a small amount of other substances decomposable at the same temper ature as the resinic. Therefore when the formation of coke structure subsequently takes place the plastic mass is under the influence of the least possible distending influence, that is to say, the least possible quantity of volatile matter is evolved at this stage.

The following examples make this clear 2-- Example L-A coal gave 40% volatile mat ter at 900 C. on the ash tree and dry basis and contained 12.6 resinic matter when extracted with boiling phenol, and 26% {5 cellulosic matter and evolved 21% maximum volatile matter at 350 C, The whole of its and 7.26%

resinic matter such as decomposed at 400 The virgin coal ve a soft sintered semlcoke on direct cai zonization at 500 C. and a soft sinter coke when carbonized direct at This coal was preheated as follows 1 It was heated in thin lagers (1") mechanically agitated at 350 for 1% hours. The coal lost 10% by weight. The product contained 8.6% of resinic matter, and gave less than 0.5% matter volatile at 300 C. volatile matter at 350 C. On crushing the cooled product and subsequently submitting it to the process of coke formation at 480 C. a dense hard smokeless fuel (with 10.3% volatile at 900 C.) was obtained, gallons per ton of oil being obtained. The coke formation took place in layers- 3" thick, and this stage was com-\ plete in 2?; hours. Metallurgical coke was made as follows: The operation up to the formation of coke structure was conducted as in the revious case, but instead of discharging t e smokeless fuel from the oven, it waspushed into an oven at 900 C. for 1% hours, the coke resulting was of a dense hard nature and had only 0.6% volatile at 900 C. The yield of oil was again 25 gallons and the equivalent of 24 lbs. of ammonium sulphate was produced per ton.

Example 2.A coal of 28.6% volatile at I 900 C. gave 15% (ash free dry basis) total volatile'at 400 0.; it contained 21% resinic matter and 22% (5 cellulosic. The resinic matter was wholly destroyed at 450 C. The coal was preheated for 1 hour at 300 C., then for 2} hours at 420 C. The result-in residue contained 9% resinic matter. t gave no volatile at 350 (3., 6% total volatile 1st 400 C. and contained only 1.6% 6 cellu- The roduct was in the form of a very soft co e; this was crushed and the formation of: coke structure performed at 600 C. A dense hard smokeless fuel containing 4.5% volatile matterat 900 C. resulted. The yield of oil was 24 llons.

It is to be noted t at I have shown that in the virgin coals coke structure is formed at temperatures varying from 350 up to 450 according to thenature of the coal; in the case of t e highl, bituminous coals the temperature deal; he lower; limits. Now.;.i-;.i-; these coals are carbonized at low tempera tures and-the resulting residue heated to higher temperatures the: coke structure initially formed persists. Usually any coke structure .formed in the preheating is broken deWn' 'by grinding prior to the process of the formation of coke structure at about 500-600C.

It.-.-has been found that coke is formed at temperatures varying from 350 to 500 C.

according to the nature of the coal and furthe'rcertain coals of a high volatile connot exceedin tent at 900 C. which do not coke under present practice can be coked at temperatures from 350-500 C. rovided that these are of such nature that t ey can be suitably preheated so as to leave 56% resinic matter in the preheated coal. And it has been found that when the coke structure is formed this structure will remain throughout the mass of coke independently of the temperatures the coke may be subsequently submitted to. The resinlc matter in coal which has been maintainedabove 500 C. for a short period will be decomposed and no further coking eifect can be produced as the resinic matter is the coke producing ingredient in the coal so long as the amount of resinic matter is above 5% and all resinic matter is decomposed at 450 to 500 C. Resinic matteris of different degrees of stability and associated with it is non-coke producing matter which decomposes below 500 C., the result being that if coal is coked without preheating at 400 to 500 C. the resinic matter is only slowly decomposed and the non-cokingmatter causes the lastic mass to distend and a porous coke is produced. This distention is more marked with coal containing large quantities of volatile matter. If however-the coal is suitably preheated the product on coking does not expand but in many cases contracts.

According to the present invention as above state coalis preheated as described in our former specification and is coked in an oven in which the temperature does not exceed, 600 C. but which preferably does not exceed 500 C. to form the coke structure: The roduct may afterwards be beated to a higlier temperature.

It is common knowledge that the bye products obtained from the carbonization of coal vary in nature and amount with the temperature employed. When high temperatures (say 900 C.) are used, the earlier termed products are decomposed and undergg change from open chain compounds and lly saturated c ain compounds tosubstances of the aromatic series and concurrent with this change the volume is decreased. The critical range of temperatures for this change is from 500 C. to 600 C. and consequently ifbye products are required of a quality suitable-for refining into substitutes for natural petroleum products, I coke the preheated coal at a temperature 500 C.; if however it be desired to pr uce bye products for use as a fuel or in'an unrefined state a temperature above 500 C. but below 600 C. may be used. The effect of the higher temperature on the nature of the'coke is to cause'slightly greater porosity therein due to the steeper temperature gradient in the mass undergoing carbonization; this fact can be minimized by preheating the coal 'to the greatest extent possible i. e. to leave therein the minimum uantity of resinic substance necessary for t e production of coke.

Further the valuable bye products arise in the main from the substances in coal decomposed below 500 (3., conse uentl in carbonizing coal the portion sta lo a ve this temperature is of little value by comparison, for the production of bye products. I therefore preferably carry out the formation of coke structure at a maximum temperature of 500 (3., but in some cases T may use a higher temperature not exceeding 600 C.

' In the case of the preheated coals whose non-coke producing constituents are decomposed below 500 C. it is found that the nearer the temperature at which the coking is conducted to the temperature of decomposition of the resinic matter therein, the more dense the structure of the coke. Thus if coals are used in which the major portion of the resinic matters decompose around 400 C. it is preferable in order to obtain a dense coke to coke the preheated coal nearer to i50 C. than 500 C.

For example the coal is heated for from 3 to 4 hours at 400 C. or for a shorter period at a higher temperature, ea 450 C.- The product after. crushin (i necessary) is placed in an oven in w ich the tem rature 18 about 500 C. and a coke containing 10% of volatile matter nd of a dense hard nature is obtained. lit this coke is heated for two hours at 000 C. volatile matter will be driven 05 leaving 5% of volatile matter, and if heated for 1%- hours at 700 C. the coke will contain 2% to 3% volatile matter, or

if heated for. 1 hour at 900 C. practically no volatile matter will be left in the coke. Thus the de e and time to which the product is heat after the formation of the coke structure at about 500 C. depends upon the product re uired. The coke may be obtained by using a higher temperature than 500 C. but 500 (1 is the maximum temperature for the formation oil coke structure and gives a higher yield of liquid bye products, a denser structure of coke which contains around 10% volatile and can be burnt under normal conditions of combustion.

The coal maybe preheated in stages as described in my former specification. F or example coal containing 28.6% volatile matter at 900 C. was heated for a period at 300 C. and then the temperature was slowly raised to 420 (3. for another period, and the product was shot into an oven having a temperature otfrom 480 to 500 (3., the re sult being that a dense hard coke was obtained; this can be'used as a fuel. This coke contained 10.3% volatile matter and was heated to a temperature of 900 C. A

dense hard coke of the original structure was-formed containing 1.2% volatile matter.

The drawin show diagrammatically an apparatus which ma be umd in carrying out this invention. higure 1 is a plan of one end of an oven and Figure 2 is a side elevation of part of one of the sides of the oven.

The oven is of ellipsoid form having guides (1 upon which run the wheels b b on one side and the wheels 0 on the other side of each of a number of truck frames (1 coupled together by links 6. To the frames d are pivoted trays fiend the trays are provided with jockey w eels g. On the frames (1 and the links 6 are ratchet teeth It adapted to engage with a toothed wheel 2' on the same axis j as another wheel is which wheel k may be driven in any desired manner. The ratchet It comes below the wheel 2" whereby the truck is driven and the whole system of trucks moves round the oven. At one side of the oven is a feed hopper m having a measuring device n so that when a truck arrives beneath the hopper m the requisite amount of material is delivered on to the tray f. When the trucks have completed a'circuit of the oven they deliver their contents into a chute 0 which may lead to a cooling chamber or to a furnace to be further heated. The trucks may be operated intermediately or continuously by varying the drive of the wheel 7:.

By the use of such an apparatus thin layers of the material may be heated continuously so that a more uniform heatin and a shortening of the time required is o tained than when the material is heated in large masses. Difierent parts of the ovens may be heated to diderent temperatures so that the mrials may be heated in stages.

What ll claim is 1. The process of coking coal in which the coal is submitted to heat out of contact with air in order to destroy the'non-coke producing substances in the coal but tn leave 5% by weight of the resinic substances in the product in order to prevent expansion of the coke during the coking process and then colting the preheated coal at a temperature which does not exceed 500 C.

2. The process of coking coal in which the coal is heated for definite periods at increesa ing temperatures out of contact with air in order to destroy the non-coke producing substances in the coal but tofleave 5% by weight of the resinic substances in the roduct in order to prevent expansion or the coke during the coking process. and than coking the preheated coal at a temperature which does not exceed 500 C.

3. The process 0t coking coal in which the coal is submitted to a temperature below 400 (3. out of contact with air in order to destroy the non-coke producing substances in the cool but to leave 5% by weight oi the regime ubstances in the product in order to then cokin prevent expansion of the coke during1 the coking process and then coking the pre eated coal ata temperature which does not exceed 500 C.

4. The process of coking coal in which the coal is heated for definite periods at increasing temperatureslaelow 400 C. out of contact with air in order to destroy the noncoke producing substances in the coal but to leave 5% by weight of the resinic substances in the product in order to prevent expansion of the coke during the coking process and then coking the preheated coal at a temperature which does not exceed 500 C.

5. The process of coking coal in which the coal is submitted to heat out of contact with air in order to destroy the non-coke producing substances in the coal but to leave 5%Ob1y weight of the resinic substances in the r uct in order to prevent expansion 0 the coke during the coking process, crushing the product and then coking the crushed product at a temperature which does not exceed 500 C;

6. The process of coking coal in which the coal is submitted to a temperature below 400 C. out of contact with air in order to destroy the non-coke producing substances in the coalbut to leave 5% b weight of the resinic substances in the pr not in order to prevent expansion of the coke during the coking process, crush the product and the crush product at-a temperature w ich does not exceed 500 C.

7. The process of coking coal in which the coal is submitted to heat out of contact with air in order to destroy the non-coke producing substances in the coal but to leave 5% by weight of the resinic substances in the product in order to prevent expansion of the coke during the co ing process, then coking the preheated coal at a temperature which does not exceed 500 C. and then heating the product to a. higher temperature to drive oil the volatile matter to obtain a product easily removed from the retort.

8. The rocess of cokin coal in which the coal is heated for de nite periods at increasing temperatures out of contact with air' in order to destro the non-coke producing substances in t e coal but to leave 5% by weight of the resinic substances in the product in order to prevent expansion of the coke during the coking process, then coking the'preheated coal at a temperature which does not exceed 500 C. and then heating the product to a higher temperature to drive 0 product easily removed from the retort.

9. The process of coking coal in which the coal is submitted to at-temperature below 400 C. out of contact with air in order to destroy the non-coke producing substances in the coal but to leave 5% by weight of the resinic substances in the roduct in order the volatile matter to obtain a' to prevent expansion of the coke during the cokin process, then coking the preheated coa at a tem erature which does not exceed 600 C. and tlien heating the product to a higher temperature to drive oil the 'volatile matter to obtain a product easily removed from the retort.

10. The process of coking coal in which the coal is heated for definite periods at increasing temperatures below 400 C. out of contact with air in order to destroy the noncoke producing substances in the coal but to leave 5% by weight of the resinic substances in the product in order to prevent expansion of the coke during the coking process, then coking the preheated coal at a 4 temperature which does not exceed 600 C. and heating the product to a higher temperature to drive off the volatile matter to obtain a product easily removed from the retort.

11. The process of coking coal in which the coal is submitted to beat out of contact with air in order to destroy the non-coke producing substances in the coal but to leave 5% by-weight of the resinic substances in the product in order to prevent expansion of the coke during the cokin process, crushing the product, then coking t e crushed product at a tem rature which does not exceed 600 C. an then heating the product to a higher tem erature to drive of! the volatile matter to o ain a product easily removed from the retort.

l 12, The process of coking coal in which the coal" is submitted to a temperature below 400-G. out of contact with air in order to destroy the non-coke producing substances in the coal but to leave 5% by weight of the resinic substances in the product, crushing the product, then coking the crushed product at a temperature which does not exceed 600 C. and t en heating the product to a higher temperature to drive ofi the volatile matter to o tain a product easily removed from the retort.

13. The process of coking coal in which the coal is submitted to heat out of contact with air in order to destroy the noncoke producing substances in the coal but to leave 5% by weight of the resinic substances in the product in order to prevent expansion of the coke during the coki process, and then coking the preheated coa at a temperature which does not exceed 600 degrees C. to obtain a product easily re moved from the retort.

14. The process of coki coal in which the coal is heated for 'de nite periods at increasing temperatures out of contact with an in order to destroy the non-coke producmg substances in the coal but to leave 5% by weight of the resinic substances in the product in order to prevent expansion of the coke during the coking proces, and then meee're order to prevent expansion of the coke during the ooki proce$, crushing the product and then coking the crushed product et a tempereture whlch does not exceed 600 degrees C. to obtain a from the retort.

In testimony that I cleirn the foregoing es m invention 1 heve signed my neme this third dey of Au st,' 1921.

STEWART ROY ILLINGWURTH.

product easily removed to

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