WO2000044854A1

WO2000044854A1 - Batch thermolytic distillation of carbonaceous material

Info

Publication number: WO2000044854A1
Application number: PCT/US1999/030002
Authority: WO
Inventors: William Dell'orfano
Original assignee: Sector Capital Corp
Current assignee: Sector Capital Corp
Priority date: 1999-01-27
Filing date: 1999-12-22
Publication date: 2000-08-03
Anticipated expiration: 2001-07-27

Abstract

A distillation unit for batch thermolytic distillation of lump carbonaceous material is suitable for side-by-side mounting of multiple units. The unit includes a reactor bath for holding molten tin at approximately 455°C, a retractable lid with a hydraulic hold-down clamp, a reservoir for storing molten tin, and a basket pivotally mounted within the reactor bath. The lid includes a perimeter curtain wall and a perforated screen. A process for batch thermolytic distillation of lump carbonaceous material includes rotating a porous basket into a reactor bath by rotating the basket about an axis passing through the reactor bath; putting a charge of wood into the basket; closing a retractable lid onto the reactor bath; filling the reactor bath with molten material to produce gas and char by thermolytic conversion of the charge, draining the reactor bath of molten material while the lid is closed; quenching the char in the reactor bath with steam; opening the lid; and removing the char from the basket.

Description

BATCH THERMOLYTIC DISTILLATION OF CARBONACEOUS MATERIAL

Technical Field The invention relates generally to transformation of carbonaceous material such as waste wood into liquid hydrocarbons and char.

Background Art The need for better methods for disposal of waste products has long existed. Society now recognizes the need to handle waste products in an environmentally sound manner that avoids building landfills and creating air or water pollution. Further, carbonaceous material may yield commercially desirable products. The concept of using molten metal, including lead, tin, etc. for the thermal conversion of organic matter into useful products is generally known. US Patent No. 2,450,550 to Stamm discloses distillation of granular wood or coal by submerging the granules in a molten metal bath and passing the granules through the bath, sandwiched between two endless screens. US Patent No. 3,977,960 to Stout et al . discloses thermal conversion of crushed oil shale into useful products in a chamber containing molten metal or salt in the absence of air, and the use of recovered oil in air sealing means (column 4, line 19) . US Patent No. 5,085,738 to Harris et al . discloses thermal conversion of organic wastes, including vehicle tires, into useful products in a chamber containing molten lead, in the absence of air, utilizing gravity rather than a container or the like to convey the wastes through the molten lead. US Patent No. 5,693,188 to Donnohue et al . discloses thermal conversion of organic wastes, including vehicle tires and plastics, into useful products in an elongated chamber containing molten lead, in the absence of air, utilizing an auger to convey the wastes through the molten lead. US Patent No. 5,605,551 to Scott et al . discloses a process for thermal conversion of biomass such as wood to liquids by pyrolysis in a fluidized bed in which the conveying gas contains low and carefully controlled amounts of oxygen. US Patent No. 5,584,970 to Schmalfeld et al . discloses a process for thermal conversion of biomass such as wood to charcoal, the process involves drying the wood in a first flow of hot gas and then carbonizing the wood in a second flow of hot gas.

Throughout the world, there are millions of tons of wood scrap waiting for a reasonable way of recycling. Actual utilization of the wood scrap in the industrialized countries are:

1) Combustion in furnaces to produce electric power and steam.

2) Conglomeration to produce low quality dirty wood, tools or furniture.

3) Reforming of pallets.

4) Production of wood-dust for drying purposes.

5) Recovery of cellulose raw materials.

6) Production of coke carbon by pyrolysis.

The prior art has not suggested a commercially viable processing method and apparatus for thermal conversion of scrap wood into commercially desirable products. As a consequence, any activity which creates significant quantities of scrap wood presents the owner with a costly disposal problem. Typically, the owner ships the scrap wood from his site to another site for disposal. Thus, the owner pays to ship the scrap wood off-site, and then pays burial or other disposal fees for disposing of the scrap wood. Disclosure of Invention Objects of the Invention

A principal object of the present invention is to provide an improved process and distillation unit for on- site thermal conversion of scrap wood or other organic matter into commercially desirable products in a way that minimizes the disposal problems faced by the owners of sites that create significant quantities of scrap wood. Further objects are to provide an improved process and distillation unit wherein scrap wood is immersed in molten material and thereby converted to gaseous hydrocarbons and char; to further provide such a process wherein scrap wood is thermally converted to vapor forms that may be condensed and further separated to commercially valuable hydrocarbons and char; to further provide such a process wherein residual solids from the thermal conversion, including char, are captured and separated; to further provide such a process wherein a portion of the combustible vapors emitted from the thermal conversion of organic matter is utilized to heat the molten material bath in the reaction bath; to further provide such a process and apparatus that minimizes the risk of exposure of operating personnel to the high temperatures of the molten material; to further provide such a process wherein the self-ignition of combustible products is prevented by maintaining an effective barrier between hot combustible products and air; to further provide such a process wherein the process fluids are recycled to minimize both heat loss and release of environmental pollutants; to further provide such a distillation unit adapted to accept input from an on-site loading platform used on typical scrap wood source sites; to further provide such a distillation unit adapted to deliver output to a conventional belt conveyor system used on typical scrap wood source sites; to further provide such a distillation unit adapted for side by side mounting of multiple machines between a loading platform and a belt conveyor system to facilitate proper sizing of throughput capacity at each site; to further provide such a process and distillation unit that is relatively simple, and utilizes inexpensive equipment. Summary of Invention

The present invention provides an apparatus and process for batch thermolytic distillation of lump carbonaceous material .

A preferred embodiment of the apparatus includes a distillation unit including a reactor with a reactor bath adapted to hold a molten material selected from a group of molten materials consisting of molten metal and molten salt, a retractable lid, and a basket pivotally mounted within the reactor bath between a pair of opposing reactor bath walls.

In a distillation unit intended for side-by-side mounting of multiple units and for receiving a charge of wood from above a first end of the unit, the reactor is located at a first end of the unit, and the basket is pivotally mounted for rotation toward a second end of the unit, opposite the first end.

The preferred embodiment includes at least one hydraulic hold-down clamp attached between reactor and lid. The lid includes a perimeter curtain wall having a beveled lower rim shaped to fit a facing beveled rim of the reactor bath, and a perforated screen.

In a preferred embodiment the reactor further includes an inlet conduit for molten material, an outlet conduit for molten material, and a reactor gas outlet; and the unit further includes a reservoir for storing molten material, the reservoir having a supply conduit coupled to supply molten material to the reactor inlet conduit, and a return conduit coupled to accept molten material from the reactor outlet conduit. The base of the reactor is higher than the top of the reservoir by approximately three feet . The reservoir includes two compartments with a check valve connecting them, a pressurized air inlet, and a controllable vent. The reservoir also includes an excess-air heater, and a corrugated heat exchanger. The distillation unit further comprises a steam generator with a flu pipe and the reservoir further includes an excess-air heater flu, and a bypass flu pipe with a control valve . The bypass flu pipe is connected between the excess-air heater flu and the steam generator flu pipe. The reactor bath includes a wall conduit. The distillation unit further includes a condenser with a particulates trap having a pressure region below atmospheric pressure .

The present invention also provides a process for batch thermolytic distillation of carbonaceous material . In a preferred embodiment, the process includes rotating a porous basket into a reactor bath; putting a charge of wood into the basket; closing a retractable lid onto the reactor bath; and filling the reactor bath with molten material to produce gas and char by thermolytic conversion of the charge . The molten material is preferably molten tin at a temperature of approximately 455°C. Rotating the porous basket into the reactor bath includes rotating the basket about an axis within the reactor bath. Closing the lid includes translating the lid and lowering the lid. The preferred embodiment further includes forcibly holding the lid closed while the temperature in the reactor bath is above a predetermined temperature .

Filling the reactor with molten material includes moving molten material by gravity or by air pressure . The process preferably includes moving molten material through the basket for a predetermined period of time after filling the reactor bath with molten material, and raising the surface of the molten material at a sufficient rate to ensure that steam given off from newly heated charge effectively prevents oxygen from reacting with newly formed char. The molten material is preferably heated using an excess air heater using combustible fluids produced in the reactor bath and further using heat from hot air recovered during condensing to heat the molten material . A flow of molten material through the reactor bath is preferably maintained during thermolytic distillation.

In a preferred embodiment, the process further includes draining the reactor bath of molten material while the lid is closed; quenching the char in the reactor bath with steam; opening the lid; and removing the char from the basket . Draining the reactor bath includes driving superheated steam into the reactor bath. Superheated steam is produced at a temperature of about 228°F, and a pressure of about 20psi, using flu gas from an excess air heater. The char is quenched with steam until the temperature of the char is below a self-ignition temperature. Opening the lid includes raising the lid using hydraulic actuators, and retracting the lid using a drive screw to place the lid under a lip of a loading platform. Removing the char from the basket includes rotating the basket about an axis within the reactor bath.

In a preferred embodiment, the process further includes condensing, in a pressure region below atmospheric pressure, a mixture of gas from thermolytic conversion of the charge and steam introduced in quenching.

Brief Description of Drawings FIG. 1 is a schematic representation of a first embodiment of the distillation unit of the invention. FIG. 2 is a partial cut-away perspective view of multiple distillation units of FIG.l between an on-site loading platform and a belt conveyor system.

FIG. 3A is a cut-away elevation view of the reactor, the loading platform, and the reactor lid of FIG 1, illustrating the retraction and replacement of the lid. FIG. 3B is a perspective view of the lid carrier and basket carrier of the embodiment of FIG.l. FIG. 3C is a schematic elevation view of the lid carrier and basket carrier of FIG. 3B, giving more detail.

FIG. 3D is a cut-away perspective view of the basket carrier and pivot plate of the embodiment of FIG. 1.

FIG. 4 is a schematic elevation view of the reactor, the loading platform, and the basket of FIG.l, illustrating the loading of the basket with wood.

FIG. 5 is a schematic elevation view of a portion of FIG.l, showing the basket tipping the char onto the conveyor system.

FIG. 6 is a schematic perspective view of a portion of the embodiment of FIG.l, illustrating the flow of molten metal through the reservoir and through the reactor. FIG. 7A is a schematic perspective view of a portion of the reservoir, showing the excess-air heater.

FIG. 7B is an enlarged portion of FIG. 7A, giving detail of the excess-air heater.

FIG. 8 is a schematic perspective view of the condenser of FIG.l.

Detailed Description of Invention General

The invention provides a process and a distillation unit for converting carbonaceous material into useful product by thermolysis (dissociation of a compound by heat in a bath of molten metal, or molten salt, in the absence of oxygen) . In a preferred embodiment the invention provides a process for converting wood to wood- petrol and char by immersion in molten tin at a temperature of approximately 851°F (455°C) . The Distillation Unit Distillation unit 11 of the preferred embodiment, which includes frame 10, is shown in FIG. 1 between loading platform 110 and belt conveyor system 120. FIG. 1 shows reactor bath 19 of reactor 20 in the reaction phase containing molten tin 21 and porous basket 30, with retractable lid 40 on top of the reactor. The front of distillation unit 11 is shown beneath loading platform

110. The back of the distillation unit is shown beneath belt conveyor system 120. "Front to back" defines a long axis of the distillation unit.

Multiple distillation units, 11, 12, 13, etc. may be mounted side-by-side, as shown in FIG. 2, to match the throughput requirements of a given site. The retraction and replacement of the lid with respect to loading platform 110 and conveyor system 120 is shown in FIG. 3A. The loading of reactor 20 with a charge of lump wood 100 from the loading platform is shown in FIG.

4. The tipping of char 130 from basket 30 onto the conveyor system is shown in FIG. 5.

The reactor is fabricated from stainless steel AISI 310 or other material resistant to the temperature and chemicals involved in the process. FIG. 1 shows reactor 20 having a reactor gas outlet 25, an inlet conduit 26, and an outlet conduit 27.

The purpose of basket 30 is to contain wood in the reactor before and during the reaction phase and to carry char out of the reactor after the reaction phase. The walls of the basket are made of heavy wire mesh or heavy pressed steel having multiple apertures 38 which allow the molten tin to penetrate the basket and contact the lump wood. In a preferred embodiment the basket is 60 inches long, 36 inches deep and 60 inches wide. Apertures may be formed by the wire mesh construction shown in FIG. 3B or may be narrow slits as in expanded pressed steel . In either case the apertures need to be small enough in at least one dimension to prevent pieces of wood having small cross section from falling out of the basket through the apertures . The wood to be processed has a maximum cross section to ensure that all of the wood is fully cooked in the fixed immersion time that the apparatus is designed to provide.

The basket is pivotally mounted about a pivot axis that is transverse to the long axis of the apparatus. FIG. 3D shows the basket carrier of the embodiment of FIG. 1, and pivot bar 32 and pivot plate 37 which together define a pivot axis within reactor bath 19. In a preferred embodiment, pivot bar end 33 extends though side wall 28 and pivot plate 37, and is attached to the lower end of basket carrier lever 36. Pivot plate 37 provides a pressure seal bearing to maintain the integrity of reactor vessel 20. To tip char from the basket, basket carrier actuator cylinder 34 pulls basket carrier drive rod 35 down so as to rotate basket carrier lever 36 and basket 30 about the pivot axis. FIG. 3D also shows the basket having apertures 38. In an alternative embodiment, not shown, pivot bar 32 may be supported by a pivot plate wholly within the reactor bath and a rotational drive may be detachably coupled to pivot bar 32 only while the lid is retracted.

Referring again to FIG. 1, reactor 20 has a double wall

22, including inner wall 82 and outer wall 83, that defines a wall conduit 23. The double wall substantially surrounds the reactor. Gas given off in the reactor during the reaction phase flows through wall conduit 23, thereby providing thermal insulation for the molten tin in the reactor.

Below the reactor is reservoir 50 which stores molten tin for use in the reactor. Reservoir 50 has a supply conduit 51 coupled to supply molten tin to the reactor via inlet conduit 26. Reservoir 50 also has a return conduit 52 coupled to accept molten tin from outlet conduit 27 of the reactor. To drive molten tin into the rector, and to receive molten tin from the rector, reservoir 50 has a first compartment 56 coupled by check valve 107 to a second compartment 57, a pressurized air inlet 54, and a controllable vent 55. To allow molten tin to drain from the reactor under gravity, the top of reservoir 50 is approximately three feet below the base of reactor 20. Reservoir 50 also has a corrugated bottom heat exchanger 53, and an excess air heater 60 for heating the molten tin in the reservoir. Heater 60 has a fuel supply line 61, and an air blower 62 set for a 10:1 ratio, air to gas, at the burner. Hot gas enters heat exchanger 53 at a temperature above 480°C, and leaves at a temperature in the range 310-320°C via excess-air heater flu 63. A first portion of the gas from flu 63 supplies heat to steam generator 70.

Steam generator 70 supplies quenching steam to the reactor during the quenching phase via steam conduit 71.

The steam generator receives water from water supply 72, and heat from a first portion of hot gas from flu 63.

Exhaust from the steam generator at a temperature of approximately 260°C is vented via flu pipe 73. A second portion of hot exhaust gases passing through flu 63 is vented via bypass flu pipe 74 and flu pipe 73, under control of flu pipe control valve 75. Valve 75 is used to stabilize the temperature of hot gas entering the steam generator.

Condenser 80, shown in FIG. 8, condenses reactor gas given off in the reactor during the reaction phase. The condenser accepts gas from reactor gas outlet 25 via gas inlet 81, and delivers hydrocarbon condensate to collection tank 90. Collection tank 90 is coupled to supply fuel to excess air heater 60 via combustible gas outlet 91 and fuel supply line 61. The condenser includes a particulates trap (not shown) and a pressure region of about 1" water below atmospheric pressure. Liquids leave the condenser via liquids drain 92.

The Process

FIG. 1 shows the distillation unit in the reaction phase of a batch thermolytic distillation cycle. The previous batch cycle ends with the lid retracted, as illustrated in FIG. 3A, the char from the previous cycle having been discharged onto the conveyor system, as illustrated in FIG. 5.

A preferred process for batch thermolytic distillation of carbonaceous material , according to the present invention, proceeds as follows.

Loading a Charge of Wood

Referring to FIG. 3D, basket carrier 31 moves porous basket 30 from its tipped position (the upper position shown in FIG 5) to its operational position inside reactor 20. To do this, basket carrier 31 rotates the basket about a pivot axis defined by pivot bar 32 so the basket moves along arc B-B of FIG. 5. Then, as shown in FIG. 4, a charge of wood 100 is pushed by bulldozer or other means into basket 30. With the charge of wood in the basket, lid carrier 41, shown in FIG. 3B, moves lid

40 from its retracted position shown in FIG 3A to its

"reactor closed" position on top of reactor 20, as shown in FIG. 1. To reach the "reactor closed" position, the lid is driven first horizontally to a position directly above the reactor, then down onto the reactor, as shown in FIG. 3A by arrows A-A, by bi-rotational drive motor 45 operating to turn screw 46 (shown in FIG. 3C) . Then the lid is pulled down onto the reactor and closed tightly by force exerted by hydraulic cylinder actuators 48. These hydraulic cylinder actuators actively hold the lid down while the lid is in its "reactor closed" position. This ensures that the reactor is tightly sealed during all phases of operation while the reactor is closed. Perforated screen 42 (FIG. 3A) extends downward from the lid and fits within the opening of the basket. When the reactor is filled with molten tin, screen 42 extends below the surface of the tin so that all of the charge is enveloped by tin. Otherwise, because the charge will tend to float, portions of the charge would be above the surface, and partially uncovered. Note also, in FIG. 3A, perimeter walls 43. These walls allow pivot bar 32 to be mounted high enough with respect to rim 29 of reactor 20 that tipping can occur. Rim 29 is beveled so that char tipped from the basket does not fall back into the reactor. Lid rim 44 is also beveled to properly mate with the reactor rim.

Tin Flow: Filling, Maintaining and Emptying the Reactor Reactor 20 is filled with molten tin from reservoir compartment 56 by application of air pressure to the surface of the tin within reservoir compartment 57.

Molten tin returns from the reactor to the reservoir either by gravity or by application of steam pressure to the surface of the tin within the reactor. In the preferred embodiment, the reactor fills in approximately 60 seconds. The process of filling, maintaining and draining the reactor is illustrated in FIGS. 1 and 6. Referring to FIG. 6, the initial settings and sequencing of the tin flow valves is as listed in Table 1 below. Gas Flow

Heating the charge in the reactor produces gas and char. Referring once more to FIG. 1, the char remains within the basket while the gas exits the reactor via gas outlet slot 24, and is conveyed to condenser 80 via reactor gas outlet 25 and reactor gas inlet 81. A. Valve Position:

101: Closed, 102: Open, 103: Closed, 104: Open, 105: Closed.

With valves set as above, liquid tin is pressurized from air injected into first compartment 56, through valve 102. Liquid tin flows past check valve 106 and into the reactor. Tin fills up the reactor and overflows through pipes into second compartment 57, past check valve 108. Compartment 57 is vented through valve 104.

Check valve 107 stops tin flow into compartment 57 while under pressure.

B. Valve Position:

101: Open. 102: Closed. 103: Open. 104: Closed. 105: Closed.

When compartment 56 is at a predetermined low level, valves 101-105 are set as above and liquid tin is pressurized in compartment 57. Check valve 108 holds.

Check valve 106 holds. Check valve 107 allows flow from compartment 57 to compartment 56. When compartment 56 is at a predetermined high level, valves change and flows are as described in A. A & B repeat until charge in reactor has been immersed in high temperature for 15 minutes.

C. Valve Position:

101: Open. 102: Closed. 103: Closed. 104: Open. 105: Open.

At the end of the time cycle, valves 101-105 are set as above and tin flows from the full reactor back through fill pipe by gravity, through valve 105, through check valve 108, into compartment 57, and through check valve 107 into compartment 56.

With a new load of wood, sequence restarts at A.

TABLE 1 Using Steam to Displace Tin and Quench the Char After the end of a predefined period of time, steam generator 70 forces superheated steam at 228°F and 20psi into the reactor via steam conduit 71. This forces the molten tin out of the reactor and maintains an oxygen free environment within the reactor. After the reactor has been drained of molten tin, steam generator 70 forces steam into the reactor via conduit 71, thereby quenching the char and cooling the char and the reactor to 228°F. Retracting the Lid

When reactor temperature and pressure are sufficiently low so it is safe to remove the lid, actuators 48 push the lid up, and motor 45 translates the lid horizontally

(FIGS. 3A and 3C) until the lid is located under loading platform 110 (FIG. 3A) , so retracting the lid clear of the loading path of FIG 4 and the tipping path of FIG. 5.

The char in the basket is now cool enough to be tipped onto the belt conveyor system (FIG. 5) .

Reactor Gas Processing A portion of the gas leaving reactor 20, largely a mixture of water vapor and volatile hydrocarbons produced by thermolysis, is condensed in the condenser to produce fluids. The fluids are further separated into water, combustible gases, combustible liquids and tars. Referring to FIG. 1, gas leaving reactor 20 exits downward via gas outlet slots 24, and wall conduits 23 between the double walls of the reactor. The gas then passes through rector gas outlet 25 and is received by condenser 80 at reactor gas inlet 81. The gas is condensed in condenser 80 as distillate (wood-petrol) and other condensable products. Thus combustible and non- combustible gases, and water are liberated from the charge and recovered. Wood-petrol collects in tank 90.

Wood petrol from tank 90 is separated into a light fraction, a heavy fraction, and non-condensed combustible gas in a distillation column (not shown) within the condenser. Some or all of the combustible gas is burned in excess air heater 60 to maintain the proper temperature of molten tin in reservoir 50.

Minimizing Reactor Heat Loss

Wall conduits 23 in the end walls of reactor 20 are shown in FIG. 1. Wall conduits 23 in side walls 28 of reactor 20 are shown in FIG. 3D. These conduits provide a passage for vapor produced by thermolysis. The double- wall structure of the reactor bath significantly reduces heat loss from the molten tin. Heating the Reservoir Reservoir 50 includes corrugated bottom 59, shown in FIG. 7B, which serves as part of heat exchanger 53, shown in FIG. 1. The corrugated bottom significantly increases heat exchange surface area and facilitates heat transfer between the hot gases from excess air heater 60, shown in

FIG. 7A, and the molten tin in the reservoir. The corrugated bottom also provides the strength needed to support the enormous weight of a bath of molten tin.

Referring now to FIGS. 7A and 7B, excess air heater 60 includes air blower 62, duct 67, fuel supply line 61, and perforated pipe 65, the perforated pipe having a plurality of nozzles 66. Arrows in FIGS. 7A and 7B show

"excess air" flowing over the nozzles (which in use will be emitting flame) , and heated air flowing into heat exchanger 53. On startup, excess air heater 60 may be fueled by auxiliary fuel via auxiliary fuel supply line 64 shown in FIG. 1.

Example 1 : Distillation of Wood

Molten tin is used at a temperature of approximately 851°F (455°C) . When the reactor is filled with molten tin, the depth of the tin in the reactor is 30 inches. The basket is 60 inches long, 36 inches deep and 60 inches wide, i.e. 62.5 cubic feet per basket. Wood having a maximum cross section of one inch is loaded into the basket . Wood is immersed for a predetermined immersion time of 10 minutes. This is sufficient to fully cook wood having a smallest cross section no greater than one inch.

Assuming the 62.5 cubic feet basket is loaded with a fill density of 54%, there are 1,0121b of wood in the basket. Assuming a 12 minute cycle time to provide a 10 minute immersion time, then 1,0121b of wood is treated every 12 minutes. Thus, a single distillation unit has a capacity to treat 5,0001b per hour i.e. 120,0001b per 24- hour day, or approximately 60 tons per 24-hour day. For a higher throughput rate, multiple distillation units may be used, mounted side by side as shown in FIG. 2. Experimental Results

Experimental results, from experiments on thermolysis of wood conducted on a laboratory apparatus, are listed in Tables 1-5 below. These results are from tests conducted on various dates during the period November, 1997 through January, 1998.

TABLE 1 ANALYSIS OF DISTILLATE (November 7, 1997)

TABLE 2A ANALYSIS OF TAR (November 7, 1997)

Tar for analysis was collected from a vapor exit pipe above the baskets. The material is a bituminous oil consisting of a mixture of heavy hydrocarbons

TABLE 2B ANALYSIS OF TAR (Nov. 14, 1997)

* - Water Saturated at 0.25636 psig ** - Dry Gas @ 60° F, 14.696 psig

TABLE 3 ANALYSIS OF COMBUSTIBLE GAS (Dec. 11, 1997)

TABLE 4 ANALYSIS OF DISTILLATE (Dec. 24, 1997)

TABLE 5 YIELDS OF DISTILLATE & COMBUSTIBLE GAS (Jan. 11, 1998)

ap-1407-l02.doc

Claims

What is claimed is:

1. A distillation unit for batch thermolytic distillation of lump carbonaceous material, comprising: a reactor including a reactor bath adapted to hold a molten material selected from a group of molten materials consisting of molten metal and molten salt, and a retractable lid; and a basket pivotally mounted within the reactor bath between a pair of opposing reactor bath walls .

2. A distillation unit according to claim 1, intended for side-by-side mounting of multiple units and for receiving a charge of wood from above a first end of the unit, wherein the reactor is located at the first end of the unit, and the basket is pivotally mounted for rotation toward a second end of the unit, opposite the first end.

3. A distillation unit according to claim 1, wherein the unit further includes at least one hydraulic hold- down clamp, the clamp attached between the reactor and the lid.

4. A distillation unit according to claim 1, wherein the retractable lid includes a perimeter curtain wall having a beveled lower rim shaped to fit a facing beveled rim of the reactor bath.

5. A distillation unit according to claim 1, wherein the retractable lid includes a perforated screen.

6. A distillation unit according to claim 1, wherein the reactor further includes an inlet conduit for molten material, an outlet conduit for molten material, and a reactor gas outlet; and wherein the unit further comprises a reservoir for storing molten material, the reservoir having a supply conduit coupled to supply molten material to the reactor inlet conduit, and a return conduit coupled to accept molten material from the reactor outlet conduit.

7. A distillation unit according to claim 6, wherein the base of the reactor is higher than the top of the reservoir.

8. A distillation unit according to claim 7, wherein the base of the reactor is approximately three feet higher than the top of the reservoir.

9. A distillation unit according to claim 6, wherein the reservoir includes an excess-air heater.

10. A distillation unit according to claim 9, wherein the reservoir includes a corrugated heat exchanger.

11. A distillation unit according to claim 9, wherein the excess-air heater includes a fuel inlet coupled to an auxiliary fuel supply.

12. A distillation unit according to claim 6, wherein the reservoir includes two compartments with a check valve connecting them.

13. A distillation unit according to claim 12, wherein the reservoir includes a pressurized air inlet .

14. A distillation unit according to claim 12, wherein the reservoir includes a controllable vent.

15. A distillation unit according to claim 6, wherein the unit further comprises a steam generator with a flu pipe; wherein the reservoir includes an excess-air heater with an excess-air heater flu, and a bypass flu pipe with a control valve; and wherein the bypass flu pipe is connected between the excess-air heater flu and the steam generator flu pipe.

16. A distillation unit according to claim 1, wherein the reactor bath includes a wall conduit.

17. A distillation unit according to claim 6, further comprising a condenser, coupled to the reactor gas outlet, and including a particulates trap having a pressure region below atmospheric pressure.

18. A process for batch thermolytic distillation of carbonaceous material, comprising: a) rotating a porous basket into a reactor bath; b) putting a charge of wood into the basket; c) closing a retractable lid onto the reactor bath; and d) filling the reactor bath with molten material to produce gas and char by thermolytic conversion of the charge .

19. A process according to claim 18, wherein rotating a porous basket into the reactor bath includes rotating the basket about an axis within the reactor bath.

20. A process according to claim 18, further including the step of forcibly holding the lid closed while the temperature in the reactor bath is above a predetermined temperature .

21. A process according to claim 18, wherein closing the lid includes translating the lid and lowering the lid.

22. A process according to claim 18, wherein the molten material is molten tin at a temperature of approximately 455°C.

23. A process according to claim 18, wherein filling the reactor with molten material includes moving molten material by gravity.

24. A process according to claim 18, wherein filling the reactor bath with molten material includes moving molten material by air pressure.

25. A process according to claim 18, wherein filling the reactor bath with molten material includes raising the surface of the molten material at a sufficient rate to ensure that steam given off from newly heated charge effectively prevents oxygen from reacting with newly formed char.

26. A process according to claim 18, further including the step of moving molten material through the basket for a predetermined period of time after filling the reactor bath with molten material.

27. A process according to claim 18, further including the step of heating the molten material using an excess air heater.

28. A process according to claim 18, further including the step of heating the molten material using combustible fluids produced in the reactor bath.

29. A process according to claim 18, further including the step of using heat from hot air recovered during condensing to heat the molten material .

30. A process according to claim 18, further including the step of maintaining a flow of molten material through the reactor bath during thermolytic distillation.

31. A process according to claim 1, further comprising: e) draining the reactor bath of molten material while the lid is closed; f) quenching the char in the reactor bath with steam; g) opening the lid; and h) removing the char from the basket.

32. A process according to claim 31, wherein removing the char from the basket includes rotating the basket about an axis passing through the reactor bath.

33. A process according to claim 31, wherein draining the reactor bath includes driving superheated steam into the reactor bath.

34. A process according to claim 33, further comprising the step of producing superheated steam at a temperature of about 228 °F, and a pressure of about 20psi, using flu gas from an excess air heater.

35. A process according to claim 31, further including the step of quenching the char with steam until the temperature of the char is below a self-ignition temperature.

36. A process according to claim 31, wherein opening the lid includes raising the lid and retracting the lid.

37. A process according to claim 36, wherein opening the lid includes raising the lid using hydraulic actuators, and retracting the lid using a drive screw.

38. A process according to claim 36, wherein retracting the lid includes placing the lid under a lip of a loading platform.

39. A process according to claim 31, further comprising the step of condensing a gas mixture including gas from thermolytic conversion of the charge and steam introduced in quenching.

40. A process according to claim 39, wherein condensing a gas mixture includes condensing in a pressure region below atmospheric pressure.