US1993756A - Method of processing coal - Google Patents

Description

March 12, 1935. H. STEVENS v y 1,993,756

vMETHOD 0F PROCESSING GOVAL Original Filed-Jan. 14, 1924 .2 Sheets-Sheet 1 unc-nx Illllllll Hull-n ull-nu Munn March 12, 1935. H. STEVENS METHOD OF PROCESS-ING COAL 2 Sheets-Shea?l 2 Original Filed Jan. 14, 1924 El llllllllllllllllllill I IIIIIIIIIIH Patented Mar. 12, 1935 NITED STATES METHOD OF PROCESSING COAL Harold Stevens, Cincinnati, Ohio, assignor, by mesne assignments, to Harold Stevens, trustee Application January 14, 1924, Serial No. 686,053

Renewed May 2.7, 1933 2 claims.l (C1. 2oz-13') This invention relates to a method for processing coal and the like whereby it is freed from all volatile oils and gas and a high grade of metallurgical coke is produced.

In carrying out of my invention I employ electricity as the heating agent by placing a suitable resistor element entirely through the charge of coal to be heated, said resistor becoming highly heated thereby.

I have discovered that coals have various electrical properties, and some coals are resistors o'f electricity, and also become conductors when suiciently heated.

When the coal contacting with the resistor becomes heatedit also conducts electricity which in turn heats the particles of coal so that the conductivity of the mass of coal in the charge and the heat generated thereby moves outwardly from the resistor element until the mass of the charge is completely heated, which releases the volatile oil and gas contained in the charge.

In carrying out my invention I provide a steel retort preferably cylindrical in shape which isl divided coke, with the ends of which suitable electrodes contact, the retort is then lled with finely crushed coal which completely Asurrounds the resistor element. The volatile matter is conducted from the retort to a series of condensers wherein it is cooled and condensed to liquid form, which by reason of the reduced pressure allows the vapor in the retort to pass therefrom.

These and other features of my invention are hereinafter more fully described, and are illustrated in the accompanying drawings in which:

Figure 1 is a vertical central section showing diagrammatically a suitable apparatus, embodying my invention. A

Figure 2 is a longitudinally vertical section of my improved retort, on an enlarged scale.

In these drawings A indicates a steel cylinder on the ends of which are suitably secured metal heads A. The interior of the cylinder A, and heads A are provided with a lining a of refactory material adapted to resist intense heat. The

heads A are also electrically insulated by means of a layer of asbestos, a', or other suitable material, see Fig. 2. The heads A' and their linings are provided with openings through which is inserted a resistor element B of any suitable mate- 5 rial, but preferably composed of a paper or'wood tube bf lled with finely divided coke b' against which electrodes C contact. These electrodes pass through suitable guidelsleeves secured to the outside of the heads A by means of tap-screws d, said sleeves D being properly electrically insulated from the'heads A'. The interior of the sleeves D is also provided with insulation material cl.

The outer ends of the electrodes C are pro-` l5 vided with cross bars E, to the ends of which are attached retracting springs F, which are also attached to the tap-screws d, `so that in case of shrinkage of the nely divided coke b lconstituting the resistor -B the electrodes C will be caused to follow it up, and keep it compactly pressed together-and thus avoid undue arcing.

From the two electrodes C conductors G lead to an adjustable transformer I-I, by means of l which the current supply'to the resistor B` can 25 `be regulated as may be desired.

The cylinder A is provided with suitable manhole openings A2, through which crushed coal B see Fig. 2, can be placed in the retort, enough being placed therein to ll it asV full as possible. These man-holes are .provided with covers a2 which are secured in place by means of clamps A3 so as to resist the pressure of the vapor and gas released by the coal.

'Ihis vapor and gas is carried from the retort 35 by a pipe J by which it is conveyed to a series of connected condensers K, K' and K2. The outlet pipe J is provided with a valve J2 by means of which the escape of gas from the condenser K2 can be'controlled or prevented as desired. 40

In operation, the retort A having been filled with nely crushed coal as described, and closed so that no gas can escape, electricity is then caused to pass through the the column of finely dividedcoke composing the resistor B thereby generating heat which is communicated to the particles immediately contacting therewith, and

as the coal becomes hot. gas is thrown off, which .quickly raises the pressure in the retort and conwas confined to the resistor B, it has gradually spread until the entire mass of coal has become a conductive resistance and a heat generator.

In the meantime the vapor and gas Yreleased from the coal havebuilt up a sufficient pressure to raise the temperature within the retort to any desired degree, the increased gas pressure around the chains of series of contact arcs produces extremely high temperature.

The vapor and gas, upon entering the condensers, liquefy at the different stages of reduction of temperature, thus forming A different grades of light and heavy oil, and tar.

It will be observed that I employ intense heat generated by the conversion of electric energy into heat energy by means of an easily removable resistor element which extends through the mass of material contained within a pressure retort.

By means of my invention it is possible to vary the proportion of heat radiating surface of the material undergoing distillation. For example this may be done by varying the current density through adjustment of the transformer H where alternating current is employed. By adjustment of the transformer it is possible to use only the initial resistor as the heating element or to increase the diameter of the heating element to any desired extent. In other Words, the amount of energy put in determines the temperature and, therefore, the extent to which coking of the surrounding coal is carried. Thus the diameter of the heating element can be controlled, the greater the diameter of the heating element the greater the radiating surface thereof.

Another advantage of my invention is that it provides means for the vaporization of the volatile products under the pressure of self generated vapors thereby increasing the yield of liquid organic compounds, especially of those having low specic gravity and boiling points, particularly those products suitable for use in internal combustion engines.

My inventionis based on the fact that all coals which show, on chemical analysis, a carbon-hydrogen ratio` of twenty-six, or less, have a high d-electric strength.

While I have shown but one resistor element, I can use a plurality of resistor elements if desired, the placing of the same being in accordance with the fundamental equation regarding the linear motion of travel of heat, the resultant coke showing, on examination of cross-section a series of perfect annuli as distinguished from the lngery coke produced by the present process.

When a temperature below 750 C., is used the resistor element may be composed of amorphous carbon or suitable metallic tubes coated or alloyed with tin, bismuth or cadmium, which are capable of acting as reducing elements with the free hydrogen evolved, thereby changing tarry acids into neutral compounds of great commercial Value.

When temperatures above 750 C. are employed,'the resistors are composed of columns of coke, free from. volatile matter, contained in cellulose tubes. Heat is generated by the resistance of particles of coke and the consequent chains of series and multiple-contact arcs established therein.

Increased gas pressure surrounding these arcs produces extremely high temperature and causes changes of great magnitude through the synthetic reconstruction and polymerization of the xed gases.

I prefer to use alternating current for thermal purposes, efficiency being obtained by resolving the current into as large a number of phases as possible, consistent with the mass of charge, or mechanical details of retort construction.

By employing a simple arrangement of switches, which form no part of this invention, a polyphase current can be changed to single phase when distillation has advanced to a point where it is found that single phase current is desired. Direct current can be used alternately with alternating current to aid in the electro-synthetic formation of various organic compounds.

Because of the strength of the steel shell A of the retort, and the consequent freedom from hazard of explosion and fire, I am able to conduct the distillation, by means of suitably controlled valves, under pressure of self-generated gas, the pressure being maintained on the vapors, through their course from the report and through the condensers.

The pressure control, temperature of vapor, and electro-decomposition secure the conversion of the diierent hydrocarbons into light oil of low specic gravity and low boiling point.

Before commencing the process of distillation it is advisable that desired pressure be built up with hydrogen gas by the use of mechanical means, to the desired point, after which the vapors generated lwill maintain the desired pressure.

The diierent steps in the process and operation of my apparatus, as above described may be varied as taught by experience, to meet different conditions, materials and results desired.

Having thus fully described my invention and suitable apparatus for utilizing the same, wha'- I Y claim as new and desire to secure by Letters Patent is:

1. The process of carbonizing a mass of solid carbonizable material in a closed retort in the presence of a catalyst operating to alter tarry acids to substantially neutral compounds, which comprises carbonizing the mass from the interior thereof by providing and maintaining a denite path for electrical current within and through the mass, and in passing an electric current through said path whereby the mass of the material is heated from. within outwardly and the carbonized material becomes a part of said path.

2. 'I'he process of carbonizing a mass of solid carbonizable material in a closed retort in the presence of an electrically-conductive catalyst operating to alter tarry acids to substantially neutral compounds, which comprises heating said `catalyst by passing an electric current there- HAROLD STEVENS.

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