Apparatus for thermal pyrolysis of crushed coal

• US 5,034,021 A
• Filed: 07/12/1989
• Issued: 07/23/1991
• Est. Priority Date: 07/29/1985
• Status: Expired due to Term

• Current Assignee: Reginald D. Richardson
• Original Assignee: Reginald D. Richardson
• Inventors: Richardson, Reginald D.
• Primary Examiner(s): Woodard, Joye L.
• Application Number:
  US07/378,744
• Time in Patent Office: 741 Days
• Field of Search: 48/76, 48/77, 48/63, 48/67, 48/202, 48/203, 48/210, 201/33, 201/34, 201/36, 202/86, 202/94, 202/99, 202/215
• US Class Current: 48/77
• CPC Class Codes: C10G 1/002 in combination with oil conversion- or refining processes
• CPC Class Codes: C10J 2300/0903 Feed preparation
• CPC Class Codes: C10J 2300/0906 Physical processes, e.g. shredding, comminuting, chopping, sorting
• CPC Class Codes: C10J 2300/0909 Drying
• CPC Class Codes: C10J 2300/093 Coal
• CPC Class Codes: C10J 2300/094 Char
• CPC Class Codes: C10J 2300/0956 Air or oxygen enriched air
• CPC Class Codes: C10J 2300/165 integrated with a gas turbine or gas motor gas turbine plants provided with a gas producer F02C3/28; engines using solid fuels F02B43/08
• CPC Class Codes: C10J 3/00 Production of combustible gases containing carbon monoxide from solid carbonaceous fuels destructive distillation processes C10B
• CPC Class Codes: C10J 3/20 Apparatus; Plants
• CPC Class Codes: C10J 3/58 combined with pre-distillation of the fuel

Abstract

Apparatus is described for the pyrolysis of coal comprising a pyrolysis tower through which crushed coal and hot gas are counter-currently passed. The tower enables a controlled temperature profile to be maintained in the tower, and contains inner appurtenances which define cascading passageways to promote heat exchange and mixing of the coal with the hot gas. The coal volatiles are carried out of the top of the tower by the gas. The pyrolysis tower may be conjoined with a gasifier so as to most directly utilize the char residuals remaining after pyrolysis of the coal while they are still hot to more efficiently produce a hot synthesis gas, to be used to perform thermal pyrolysis in the tower.

Claims

1. An apparatus for producing coal volatiles and hydrocarbon residuals comprising a pyrolysis tower containing:

(1) an upper section containing a plurality of vertically spaced, grate-like members, each of said members offset laterally from the member above;

(2) a mid-section containing a plurality of declined tray chutes arranged to define cascading passageways through which crushed coal is passed by gravity downwardly counter-current to upwardly flowing hot gas to the crushed coal sufficient to effect thermal pyrolysis of the crushed coal to produce the coal volatiles and hydrocarbon residuals at temperatures which avoid thermal degradation of the coal volatiles; and

(3) a bottom section which receives the hot gas and includes means for cooling the gas to prevent degradation of the coal volatiles or heat damage to the pyrolysis tower.

2. An apparatus as claimed in claim 1, further comprising a partial oxidation gasifier conjoined with the bottom end of the pyrolysis tower, wherein the hot gas is synthesis gas produced in the gasifier from gasification of the hydrocarbon residuals remaining after the pyrolysis of the coal.

3. An apparatus as claimed in claims 1 or 2 wherein the cooling means in said bottom section comprises a heat exchanger.

4. An apparatus as claimed in claims 1 or 2 wherein said mid-section of the pyrolysis tower is narrower than the upper and bottom sections so as to promote a more dense packing of the descending crushed coal and rapid rate of pyrolysis in the lower tray chutes disposed in the mid-section, said tray chutes having a surface area which enables the crushed coal particles to slide and fall to succeeding trays in broad, thin streams.

5. An apparatus as claimed in claims 1 or 2 in which the upper section is wider than the mid-section, the width of the upper section promoting free passage of volatile laden hot gas and thereby discouraging condensation of the volatiles in that section.

6. An apparatus as claimed in claims 1 or 2 wherein:

(i) the grate-like members in the upper section comprise criss-crossed grates which subject the descending crushed coal to momentary interruptions and deflections creating a semiturbulent fall pattern, said coal particles being preheated by contact with the rising hot gas, and by contact with the screen members disposed in the section;

(ii) the tray chutes of said mid-section oriented with angles of decline to form said coal particles into broad thin streams that cascade through the section from side to side in alternating directions following said trays, said coal particles being heated by contact with the trays, each other and the rising hot gas, reaching a pyrolysis temperature in the range of 850°

F. in the bottom trays of said mid-section.

7. An apparatus as claimed in claims 1 or 2 further comprising means for adding to the crushed coal feed for additional heat transfer effectiveness,

(1) a plurality of multi-sided ceramic shapes that are heated as they descend through the pyrolysis tower with the crushed coal feed;

(2) means in the said bottom section of said pyrolysis tower to recover said heated ceramic shapes; and

,

(3) means to recycle said heated ceramic shapes for re-entry to the upper section of said pyrolysis tower,

wherein;

(i) the upper section subjects the descending crushed coal and ceramic shapes to momentary interruptions and deflections creating a semiturbulent fall pattern, said coal particles being preheated by contact with the rising hot gas, by contact with other coal particles and the ceramic shapes and by contact with the screen members disposed in the section;

(ii) the tray chutes of said mid-section forming said coal particles and ceramic shapes into broad thin streams that cascade through the section from side to side in alternating directions following said trays, said coal particles being heated by contact with the trays, each other, the ceramic shapes and the rising hot gas, reaching a pyrolysis temperature in the range of 850°

F. in the bottom trays of the mid-section,

said ceramic shapes, in addition to providing heat transfer, contributing to turbulence in, and scouring of the inner surface of, said pyrolysis tower.

8. An apparatus for producing coal volatiles and synthesis gas in an integrated coal pyrolysis and hydrocarbon residual gasification system comprising:

(i) a pyrolysis tower, having an upstanding outer enclosing wall, a baffled vertical passageway and a plurality of cooling tubes located adjacent the outer wall, and

(ii) a partial oxidation gasifier in communication with the bottom end of said tower, having an adjoining downstream section which in turn has a circumferentially located radiant cooling means,

wherein said gasifier downstream section is water cooled and partially cooled synthesis gas is taken from said downstream section and fed to said pyrolysis tower and crushed coal is fed to the top of the said pyrolysis tower, descends the baffled vertical passageway and is pyrolyzed by counter-current contact with said partially cooled synthesis gas, with said partially cooled synthesis gas acting as a carrier of the coal volatiles, the cooling tubes providing means to adjust a temperature profile within the pyrolysis tower.