US1955025A

US1955025A - Low temperature carbonization apparatus

Info

Publication number: US1955025A
Application number: US493807A
Authority: US
Inventors: Sabel Franz; Hanisch Helmuth
Original assignee: IG Farbenindustrie AG
Current assignee: IG Farbenindustrie AG
Priority date: 1929-07-20
Filing date: 1930-11-06
Publication date: 1934-04-17
Anticipated expiration: 1951-04-17

Description

April 17, 1934. F. SABEL El AL 1,955,025

LOW TEMPERATURE CARBONIZATION APPARATUS Filed Nov. 6, 1930 2 Sheets-Sheet 1 Fig-l INVENTORS Franz S'alel Helmull; Hanisclx BYZllezr ATTORNEYS AAWM A ril 17, 1934. F A E ETAL 1,555,025

LOW TEMPERATURE GARBONIZATION APPARATUS Filed Nov. @1950 2 Sheets-Sheet 2 INVENTORS Franz SaZeZ BYHwir ATTORNEYS HeYmuHL Hanisck Patented Apr. 17, 1934 UNITED STATES LOW TEMPERATURE CARBONIZATION APPARATUS Franz Sahel and Helmuth Hanisch, Neuroessen, Germany, assignors to I. G. Far-benindustrle Aktiengesellschaft, Frankfort on the Main,

Germany Application November 6, 1930, Serial, No. 493,807 In Germany July 20, 1929 4 Claims.

The present invention relates to improvements In low temperature carbonization apparatus.

A process and apparatus for carrying out lowtemperature carbonization of bituminous car- Q bonaceous materials has already been proposed according to which the hot gases or vapors, which may be inert or may contain oxygen, are blown,

through the layer of fuel to be treated at 'a temperature. suitable for the low-temperature carbonization and in such amount that the layer of fuel is brought into vigorous motion on its bed, but to avoid combustion or gasification of the carbonized fuel to a higher extent than is necessary to produce the heat for carbonization.

We have now found that this process may be carried out in a specially advantageous manner with inert gases in a retort provided with several grates one above the other, the grates being permeable for gases but not to any substantial degree for the carbonaceous material to be carbonized. The carbonaceous material is supplied to the uppermost grateand passes from one grate to the other through at least one aperture in each grate provided with closing means, such as sluices intermittently opened, or with bucket wheels conveying the material from one grate to the next without allowing substantial amounts of gases to pass. The said apertures are arranged in the grates at opposite ends thereof to compel the carbonaceous material to pass over the grates in a zigzag course and are preferably provided with tubes or hoppers extending to a height above the grate corresponding to that of the desired thickness of the layer of carbonaceous material upon the grate, so that only the uppermost layer. of carbonaceous material can pass through the said apertures. The said tubes or hoppers are preferably arranged adjustable in length. The inert gases are passed into the retort from below through the series of grates and layers of carbonaceous material thereon at such a speed that each individual layer is set in vigorous motion.

The nature of this invention will be further described with reference to the accompanying drawing which in Figs. 1 and 2 shows in vertical cross-section arrangements of apparatus in accordance with the present invention. Referring to Figure 1 in detail a-denotes a low-tempera- 50 ture carbonization retort containing four grates,

. b, c, d and e, arranged one above the other. The

fuel to be subjected to low-temperature car- 'bonization, such as for example brown coal and soft coal rich in bitumen, passes from a hopper 55 I through a worm conveyer 70 onto the upper grate b. The fuel passes from one grate to an other through tubes n (extending upward from the grates into the space between two grates) combined with conduits q extending downward from the grates and provided with bucket wheels h and is finally removed through an outlet m and a worm conveyer 12 after it has been subjected to low-temperature carbonization. A burner serves to prepare the inert gases of combustion. The burner is provided with tubes p and o for 5 the admission of fuel gas and air or like oxidizing gases. The inert gases of combustion pass through the single grates, each laden with fuel, and are. withdrawn at g together with the vapors from the low-temperature carbonization. It is 7 preferable to leave a free space above each layer of carbonaceous material so that not too much dust is carried along.

Furthermore, it is preferable to construct the grates with as great a length as possible so that the fuel has to traverse a long path while passing through the retort. In this manner a better exchange of heat between the gases and the fuel is effected.

In the said Figure 1 the regulation of the height of the layers of carbonaceous material on the single grates is effected by means of the rotary bucket wheels h and the tubes n, but this may be effected equally well by other means, as for example by means of sluice valves, or by automatic means. It is essential that-the downward stream of carbonaceous material is so led in counter current to the ascending inert gases over the single grates that the fuel bed is in vigorous motion in each single stage.

With a retort constructed according to the present invention a substantially greater efiiciency is obtained than with the systems hitherto known, and an excellent protective treatment of the vapors from the low-temperature carbonization and the best utilization of the heat supplied are also obtained.

We have further found that an apparatus constructed on the hereinbefore described principle is very suitable for carrying out other heat-treatments of bituminous carbonaceous materials as for example the gasification of solid fuels.

Thus, it is especially advantageous and simple to carry out the drying, degasiflcation and gasification (for example low-temperature carbonization) in a shaft, for example rectangular or circular, so that the singleprocesses are carried out separate from each other on the horizontal or slightly inclined superimposed grates which are permeable for gas but substantially impermeable 11 bucket wheel F4.

for the fuel, the hot gases flowing through the grates from the bottom to the top while the fuel flows in counter current to the gases over the single grates from the top to the bottom through suitable opening devices. The fuel spreads itself out on the single grates in such a manner that there is a large gas space between the surface of the fuel and the grate lying next above it.

By working in this simple manner an accurate control over the single independent processes of drying, degasification and gasification is obtained. In this manner it is possible to carry out each of the three processes independently under the most favorable conditions, as for example of temperature, and still to retain the combination of the different processes in one shaft. The juxtaposition and confusion of the single processes, such as is possible for example in a shaft low temperature producer with or without low temperature carbonization insertions or attachments by reasons of the formation of grooves or channels in the bed of fuel, is entirely avoided according to the present invention.

The fuel slides from one grate to the next for example through sluices, rotary bucket wheels, mushroom valves and the like. When the crosssection of the grates is of large dimensions it is preferable to move the fuel on the single grates in order to produce beds having as uniform a thickness as possible. This may be effected for example by blowing in the air for the gasification or the hot producer or scavenging gases which flow through the shaft upwards in such a quantity as to keep the fuel in active movement on its bed or to whirl up and down, but to avoid combustion or gasification of the fuel to a higher extent than is necessary to produce the heat for carbonization. a

Figure 2 of the accompanying drawings represents a vertical section of an apparatus which is particularly suitable for carrying out the dryi ng, degasification and gasificati'on in one shaft, the single processes taking place separate from each other.

Referring to Figure 2 in detail S denotes a shaft which is divided into several chambers by horizohtal grates R1, R2, R3 and R4. The fuel, for example brown coal, is sluiced in in the usual manner from a receptacle Y by means of a hopper X and bucket wheel Z and flows in a horizontal direction over the grate R1. The fuel passes through a rotary bucket wheel F1 onto the grate R2 and from this through a rotary bucket wheel F2 on to the grate R3. Finally the fuel passes through a rotary bucket wheel F3 on to the gasifying grate R4. The ash 'of the coal gasified on the grate R4 is removed through a rotary The grates R1 and R2 act as drying zones. On the grate R3 the coal passes through the low temperature carbonization zone while the grate R4 constitutes the bottom of a lignite coke producer which may be operated with any desired temperature by means of a gasify-' ing agent such as air, carbon dioxide, steam or mixtures of these gases blown in at L. It is blown in with such a force that the gases flowing through the shaft S keep the fuel in motion on the single grates. In this manner the thickness of the fuel bed on the single grates is kept uniform and a movement from the inlet end to the outlet end takes place. The gases leave at G. Further advantages of the process according to the present invention consist for example in that irregular distribution of temperature, the formation of channels and slagglng are avoided in all cases.

The grates must offer a free passage to the ascending current of gas but on the other hand must prevent the fuel passing from one grate to the one below it except through the sluices. It has been found to be especially suitable to construct these grates by arranging fire clay plates in a thickness equal to that'of building bricks one beside another with their edges so that a small slit of from about 0.5 to 3 millimetres remains free. These grates do not allow even.finely grained material to fall through while they only offer a slight resistance to the gases which is necessary for a uniform distribution of the gases. If the fuel is completely gasified or burned on the lowermost grate, this may have any suitable shape which ensures the removal of the ash, as for example movable grates, grates with scraping devices and the like.

The process may be used with special advantage for example for brown coal which has been wholly or partly predried. When the material has been predried to a large extent, lignite coke maybe withdrawn at F4 instead of ash by only burning as much coal on the grate R4 as is necessary for the preheating and low temperature carbonization on the remaining grates.

It is also possible, to influence the working conditions on the single superimposed grates from outside besides the combustion or gasification on the lowest grate, by leading in air, carbon dioxide and the like at anysuitable place, for

example above one or more of the lower grates of fuel, through admission pipes C.

When employing steam or gases containin steam as the gasifying agent it is preferable to employ the steam in a highly superheated condition in order that the gasification may be continuous. Working in this manner renders it possible to obtain a final gas rich in hydrogen which is suitable for many purposes and moreover the sensible heat of that part of the steam which is not converted by the gasification is utilized in an advantageous manner for the low temperature carbonization.

What we claim is:

1. An apparatus for distilling and gasifying coal comprising a retort, a plurality of superimposed grates at spaced intervals within said retort, each of said'grates covering the entire horizontal cross-sectional area of said retort and being permeable to gases and adapted to support the coal to be distilled, at least one conduit for said coal in each grate, the said conduits in the several grates being out of vertical alignment, closing means within said conduits, means for feeding said coal onto the uppermost grate, means for discharging the coke from the lowermost grate, a conduit for leading gas into the bottom of said retort, and a conduit for drawing off gas at the top of said retort.

2. An apparatus for distilling and gasifying coal comprising a retort, a plurality of superimposed grates at spaced intervals within said retort, each of said grates covering the entire horizontal cross-sectional area of said retort and being permeable to gases and adapted to support the coal to be distilled, at least one conduit for said coal in each grate, the said conduits in the several grates being out of vertical alignment, closing means within said conduits, means for feeding said coal onto the uppermost grate, means for discharging the coke from the lowermost grate, a conduit for leading gas into the bottom of said retort, a conduit !or drawing on gas at the top of said retort, and a conduit for introducing gas above at least one of the lower grates.

3. An apparatus for distilling and gasifying coal comprising a retort, a plurality of superimposed grates at spaced intervals within said retort, each of said grates covering the entire horizontal cross-sectional area of said retort and being permeable to gases and adapted to support the coal to be distilled, at least one conduit for said coal in each grate, the conduits in adjacent grates being at diametrically opposite sides of said retort, closing means within said conduits, means for feeding said coal onto the uppermost grate, means for discharging the coke from thelowermost grate, a conduit for leading gas into the bottom of said retort, and a conduit for drawing off gas at the top of said retort.

4. An apparatus for distilling and gasifying coal comprising a retort, a plurality of superimposed grates at spaced intervals within said retort, each of said grates covering the entire horizontal cross-sectional area of said retort and being permeable to gases and adapted to support the coal to be distilled, at least one conduit for said coal in each grate, the said conduits in the several grates being out of vertical alignment and each conduit extending to some predetermined distance into the space between two grates, closing means within said conduits, means for feeding said coal onto the uppermost grate, means fordischarging the coke from the lowermost grate, a conduit for leading gas into the bottom of said retort, and a conduit for drawing off gas at the top of said retort.

FRANZ SABEL. HELMUTH HANISCH.