BACKGROUND OF THE INVENTION:

This invention relates to a large vacuum chamber sy tem, a new method for creating a vacuum in a large volum systems utilizing the chamber and method for vacuum fo processing and pyrolysis of hydrocarbon containing materia Many processes and procedures need or benefit from vacuum to produce desired results. In freeze-drying food, for example, a vacuum is used to lower the boili point of the water in the food so that it can be remov from the food at low temperature.

Other processes involving gas flows are pressu dependent. For example, the pyrolysis of hydrocarb containing material such as oil shale or tar sands can enhanced by reduced pressure. The vapor that is creat must be removed rapidly. At ambient pressure, most mol cules reflect back from other vapor molecules toward t source material. If the hydrocarbon molecules could removed from the material at molecular speeds up to tho sands of feet per second rather than the mass transf speeds of inches or a few feet per second, the process m be dramatically speeded up. For economical pyrolysis, lar scale systems are believed necessary. Vacuum systems, ho ever, have inherently been limited in size for reasons s forth more fully below. If a large vacuum retort can b built, pyrolysis costs could be reduced depending on th process's sensitivity to pressure and the capital cost associated with implementing the vacuum.

As size increases, the total force acting on the wall of the chamber increases so the wall thickness must increas disproportionately with volume. Therefore, the main limita tion on the size of vacuum chambers is the wall thicknes necessary to sustain the collapsing forces.

The pressure acting on the outside wall of the chambe is a function of the following equation:

Where p - pressure differential between the inside an the outside of the chamber wall (psi); Ξ = modulus o elasticity = 3.0 x 10 psi (stainless steel); t ^* = wal thickness (in); 1 ^*** length of unsupported cylinder (in); an r = tank radius (in).

Although the theoretical pressure differential betwee the inside of the chamber at full vacuum and the outsid will be 14.7 psi (7.1 g/sg. cm), a safety factor for th metal chamber wall must be considered. Assume that a tan is 15 ft (4.δ ) in diameter and has a 8 ft (2.4 ) length If the wall thickness (t) is 0.5 in (12.7 mm) the tank wil withstand a pressure differential of approximately 53.5 psi Based on the 14.7 psi pressure differential that will b encountered, this is a safety factor of approximately 3. which is considered sufficient.

If the diameter of the tank is very much greater, say 6 ft (18.3 m) with a length of approximately 40 ft (12.2 ) the conditions radically change. Under equation (1) th same tank thickness of 0.5 in can withstand a pressur differential of only 1.34 psi. To withstand a pressur differential of 14.7 psi, the wall thickness would have t be increased to between 1 and 1.5 in, but that would yiel no safety factor. To yield an effective pressure differen tial with the same safety factor of 3.5, the wall thicknes would have to be approximately 2.25 in (5.72 cm). Such tank made of stainless steel would weigh more than 360 ton (327 metric tons) without any supporting structure. Th fabrication of such a structure would also be extremel costly and impractical.

One of the objects, therefore, of the present inventio is to disclose and provide a novel vacuum chamber which ca use substantially thinner walls than was heretofore though possible.

MH

Another problem in vacuum processing is that the vacu pumps must remove the initial air in the chamber and remo the evaporating volumetric contents. Large amounts energy must be expended to maintain the vacuum, and the co of such energy may make an otherwise beneficial proce uneconomical.

It is not desirable to pass the evacuants that conta condensables through the vacuum pumps. The pumps run ve much more inefficiently because of condensation within t

10 pumps. The condensate also tends to damage the pump. El borate systems have been developed to condense the condens bles between the pumps and the chamber. The condenser mu be defrosted and additional energy is necessary to cool t condenser again from its elevated temperature. Large vacu

15 chambers also use necessarily large, costly conduits connect the vacuum pumps with the chamber.

Although some of the aforesaid problems are alleviat in the higher temperature environment of pyrolysis, othe

20 are created. In pyrolysis of shale and tar sands, t source material is reduced to a relatively small partic size through crushing or some other mechanical method or explosions. powder-like fines are usually created th impede processing by contaminating the liquid condensate a _. vapor making the process substantially more difficult a contaminating the end product.

If the vapors are exposed to the atmosphere, they c become explosive and toxic. If processing occurs in vacuum, no oxygen will support an explosion. _Q As will be set forth more fully hereinafter, the proce described is a closed cycle batch process. As with mo batch processes, starting and stopping the cycle creat inefficiencies. The present invention overcomes many these problems by rather unique solutions. The prese _ invention saves the heat from a batch that has bee processed to use it on forthcoming batches. The prese invention also provides a system for loading and unloading

retort quickly . The system also minimizes the need fo external condensers so that vapors do not have to remain a high temperature until they reach the condenser. Th liquid phase can be reached efficiently within the chamb to the advantage of the system. Some of the heat o condensation can be utilized in preheating incoming or The present invention also provide structure that eliminate or removes the particulate matter that would hav contaminated the liquid phase without additional equipment.

10 SUMMARY OF THE INVENTION:

Vacuum Tank. The present invention relies on rotatin the chamber along its longitudinal axis at a relatively hig rate of speed such that the centrifugal force acting on th walls can be balanced against the pressure differentia

15 forces tending to collapse the chamber. The use of thi concept produces many surprising results in the presen environments.

The first surprising result produced is that the shel can be made very much thinner than it would have to . b

20 without rotation. The necessary thickness is calculated follows. p = G (2)

Where p - outside ambient pressure (psi); G = number o rotational gravities over one; and w = weight per unit are

25 of wall (psi) .

W = wt (3)

Where w = density of the rotating material (lbs/in ³ ); an t = wall thickness (in). By substituting (3) into (2), p - Gwt-

30 (4) G = ^* D ^ '(5)

Where K = a constant of proper units; D = tank diamete (in), and N = tank rotational speeds (rpm).

If (5) is substituted into (4) and the equation i m . solved for the rotational speed:

N = (ρ/KDtw) ^{i/2 (} 6 ⁾

It is next necessary to find the rotational spee

— ^~ ?I

-3 -

necessary so that the pressure differential between sides the tank wall will be zero, i.e. the centrifugal for exactly equal the external pressure so that there will be 5 stress on the wall due to internal vacuum.

Assume that the tank has a 60 ft diameter which is s stantially larger than the largest tanks currently in ex tence. The surface speed (v) of the tank wall representated by the following equation:

The surface speed v should be very much less than 0 Mach (335 ft/sec) in order to minimize outside surface a drag effects. Thickness t should be small in equation (S) I ⁵ reduce the rotational speed and the structural costs, but small t results in a large rotational speed which undesirable. Therefore, the weight of the material must made as large, as possible. The weight of 304 stainle steel, the preferred material for a vacuum tank for a giv ⁰ thickness is fixed, however, with a density of approximate 0.295 lbs/in . In order to increase w in equation ( without increasing the thickness of the wall, the inventi contemplates the use of a ballast lying against the insi tank walls. The ballast need not be airtight; the stainle 5 steel walls will prevent leakage. The ballast functions transfer its centrifugal force to the inside of the walls add a force against the pressure differential forces acti from the outside of the tank.

Now that it is determined that a non-structural balla ⁰ can be used to substitute for a very much thicker stainle steel wall, what is even more surprising is that the ide ballast is ice or other condensate forming on the inside the wall. Of course, lead or other high density metal cou be used as ballast, but with ice, the system creates its o ⁵ ballast of 0.035 Ibs/cu. in. density during operation. will be discussed in greater detail hereinafter, wfren t tank is used for food processing, ice forms at a desirab

rate — quickly at first. When the water content of t food is still great, it can be drawn off at moderate to l vacuum to form ice quickly and thus build the necessar ballast so that there will be sufficient ballast when high vacuum is used.

Equation (5) is modified to include a ballast term s that it becomes:

Where t. = the ballast thickness (in); and w ₁ = balla density (lb/in 3).

Equation (8) can be solved for various values of t (t wall thickness) and (the speed of the shell).

A 50 ft. (18.3 ) diameter chamber, having a wall thic ness of 1/3in (2.3 mm) rotating at 105 rpm with a surfa speed of 335 ft/sec would need about 2.5 in (54 mm) of i as a ballast in order to prevent any collapsing force full vacuum. At a slower speed of 223 ft/sec, the chamb having the same wall thickness requires almost 7in (178 m of ice, and at 112 ft/sec, the same chamber would requir more than 30 in (.76 m) of ice as a ballast. The equatio used presume that the entire center of gravity of the ice i concentrated at the cylindrical wall. As the thicknes increases, however, the average thickness moves away fro the wall to decrease the centrifugal force. Therefore, wh the equation yields relatively thick ice, either addition ice thickness will be necessary, or the speed will have t be increased in order to compensate for the loss of centri fugal force.

The drag coefficient on the shell during rotation wil be in the turbulent boundary layer region. The Reynold g

Number is approximately 4 x 10 . The drag coefficient (C, is approximately 0.0015, and the absulute drag = 1509 lbs (684 kg). Approximately 145 hp (109 kw) of power is neede to overcome air drag. The cost of rotating the tank

BAD ORIGINAL^

-1-

overco e the rotational drag is very much less than the c of the food itself. 5 Of course there will be other power losses such those associated with the bearings for a large rotat chamber as well as other inefficiencies introduced into system. However, they are very small compared to the co and value of the food or shale being processed. The ener _Q needed for rotation and the rest of the processing cycle much smaller than the energy costs in maintaini conventional food in a frozen state.

BRIEF DESCRIPTION OF THE DRAWINGS:

FIGS. 1 through 7 are directed primarily to the embod _5 ment used for food processing.

FIG. 1 represents an end view, partially in section the rotating chamber of the present invention mounted with an insulated room.

FIG. 2 shows a cross-sectional view of the rotati o vacuum chamber of the present invention taken through pla II-II Of FIG. 1.

FIG. 3 is a sectional view taken through plane III III of FIG. 2 showing an area adjacent the inner surface the chamber at its top. 5 FIG. 4 is a schematic view of the operating system the present invention showing how waste heat can be used melt some of the ice that has been chipped off ^" the inside the shell by a chipping mechanism.

FIG. 5 is a side view, partially in section, and FIG. 0 is an end view in section showing the cutter that remov ice from the inside of the cylindrical wall of the chamber

FIG. 7 is a graph showing the relationship of t desirable water thickness versus the desirable she thickness for various rotational speeds. FIGS. 8 through 13 are directed primarily to the embod ment used for pyrolysis of hydrocarbon containing material.

FIG. 8 is a side elevation of the pyrolysis syst showing the supporting materials handling systems.

FIG. 9 is an end view, partially in section, of th chamber used primarily in pyrolysis operations.

FIG. 10 is a side sectional view of a preferred e bodi ent taken through plain X-X and FIG. 3.

FIG. 11 is a plan view showing the details of th microwave heating system and the flues for conductin vapors.

FIG. 12 is a schematic of the system utilized I pyrolysis showing energy flows particularly for heating th hydrocarbon material during processing and preheating same.

FIG. 13 is a schematic showing the use of the shell a a condensing surface and a heat exchange system of th preferred embodiment to accomplish that end. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT:

Tank Construction in General. The vacuum chamber o the present invention includes an airtight generall cylindrical wall or shell and a pair of end members o airtight material attached to the cylindrical wall i airtight relationship to create a chamber. In the exemplar embodiment in which the chamber is used for food processin (FIGS. 1 and 2), chamber 10 comprises a cylindrical wall 11 which for purposes of discussion will be considered to be 6 ft (18.3 m) in diameter. The length of the cylindrical wal is approximately 40 ft (12.2 ) . The chamber in the othe exemplary embodiment, FIGS. 9 and 10 is the same diameter but slightly longer. There are structural limitations o chamber length due to compressive loading of the cylindrica walls. As the length increases, the walls begin to behav as a column in loading and become unstable. The length that were chosen for the chambers meet capacit requirements. The end members 20, 21 are attached to th cylindrical wall 11 to create an airtight chamber. Each en member, 20, 21 (FIG. 2), is reinforced either to th configuration shown in FIG. 2 so that they are thicker a their centers of pressure, or end members 220 and 221 may b shaped as shown in Fig 10. Where elements in the secon

embodiment (FIGS. 9 and 10) are similar to elements in FIG 1 and 2, the same reference numerals are used proceeded by 72 " . Thus, the construction of chamber 10 (FIG. 2) similar to chamber 210 (FIG. 10). In the first embodiment, a longitudinal shaft 12 pass through the center of each end member. The shaft may formed of two sections, 13 and 14, and the end members 2 and 21 are fixed to shaft 12 through appropriate fitti:.. 15, which must be constructed to withstand the large forces Likewise, the shaft- will have to be constructed to withstan the forces. It will be noted that the shaft is a column i compression. Because of its length, the shaft must be mad sufficiently thick and of a large enough diameter to resis the large compressive forces. The compression force from end member 21 on cylindrica wall 11 is a function of the diameter of the shaft. Thi can be calculated from the following derived equation:

_Fc = ^{L (r,} v ^" _— ^r x* ^} + ( ) 2^ P (9) v c where F_ = compressive force on shaft;

L = load on end member due to pressure differential r _v = radius of shell; r _χ -= distance from center of shell to σentroid o pressure; r = radius of shaft; and P = maximum pressure differential.

F _V = L - F _C (10)

As the diameter of the shaft increases, the force fro the end members on the cylindr.ical wall decreases thereb decreasing the compression of the shell and increasing th compression on the shaft. A shaft of large diameter i desirable to resist compression but there will have to be balance because a large diameter shaft displaces useabl volume inside the chamber. Because of differences i loading and unloading the chamber for the pyrolysi

O PI

e bodiments and because of differences in expansion becau of the much greater temperature change in that environmen no complete shaft is used in the shale processing system shown in Fig. 10. The shaft could also be eliminated in t food processing embodiment.

Vacuum means for evacuating the chamber are provide In the exemplary embodiment, the vacuum means are indicat generally at 50 (260). The details of the vacuum means the exemplary embodiment will be explained hereinafter, no that the vacuum means are within ^"" the chamber.

Drive means are attached to chamber 10 (210) f rotating the chamber along the longitudinal axis where centrifugal force of the rotating cylindrical walls 11 (21 acts against the force resulting from the pressu differential between the inside of the. evacuated chamber a ambient pressure on the outside of the cylindrical wall prevent the cylindrical wall from collapsing. In o exemplary embodiment, FIG. 2, the drive means 80 includes drive motor 81 which rotates shaft 12 through differentia drive shaft and transmission 82, 83 and 34. Chamber 10 supported above floor 27 by four posts, 22, 23 and 24 (t fourth post is not shown) . The posts support the shaft at bearings 50 and 51.

In another exemplary embodiment (FIG. 10), shafts 212 and 212 B are fixed and are stationary on the support post Motor 281 drives chamber 210 around shafts 212 A and 212 through supporting bearings 250, and 251. Bearings 250 a 251 must also permit movement of the chamber along the sha because the chamber will expand and contract from heati and cooling. Such bearings are known in the art. T chamber is driven by motor 231 through belt 232 whi engages the chamber. An auxiliary motor 235 may also used to overcome inertia during start up thereby allowi the chamber to reach its full rotational velocity quickly.

Using the teachings in the Tool Engineers Handbook, bearing can be selected for supporting the ends of t

chamber. There are off-the-shelf bearings with a size 400 mm x 600 mm x 200 mm and with a C value of 720,000 th are acceptable for some applications. The life of such bearing is computed at 2.16 x 10 ⁸ revolutions. If the ma imum rate of rotation is about 105 rpm, the bearing usef life calculates to about 3.85 years, which is qui adequate.

As motor 81 begins to rotate shaft 12 and chamber 1 the vacuum means 50 can be started simultaneously. Whi chamber 10 is rotating at a slow speed, cylindrical wall will only be able to resist a small pressure differentia However, at start-up, the pressure within the chamber wi be reduced relatively slowly because of the large volu within the chamber and the large volume of vapor bei sublimated.

It would be desirable to have a control system so th the internal pressure will not be reduced to below where t centrifugal force on the chamber walla will reduce crushi from such pressure differential. The control system, whi is shown schematically at 85 in FIG. 2 is intended t monitor both internal pressure and rate of rotation an acceleration and to control motor 81 and vacuum means 50 The controlled system also monitors strain guages 8 measuring strain in its shell 11. Ideally, it would als monitor the rate of ballast formation of ice (or petroleum on the inside of the cylindrical wall 11 so that this facto could be used in allowing for greater vacuum at lower rate of rotation.

The control system can also maintain a safe system. I the drive system malfunctions or power fails, inertia wil maintain rotation of the chamber while the pressure withi the chamber could be raised through vents 87 tied to th control system 85. If the vacuum means malfunctions, th shell can resist the centrifugal force because it will be i tension, which it is much more able to resist, rather tha in compression, which it poorly resists as shown in Equatio

OMPI

(1). Because of potential balancing problems, a system f continuously monitoring and controlling the balance as i build up and load changes is contemplated.

At start-up, the food being processed will also have large water content and will be relatively warm, which wi contribute to the vapor pressure within the chamber. In sense, in the beginning, it will be more difficult to redu the pressure in the chamber because of the addition- molecules subliming from the food product. Food Processing - The Low Temperature Embodiment. F one embodiment, cooling means are provided for cooling t outside of the chamber to reduce the temperature within t chamber. The first exemplary embodiment (FIGS. 1 - 6 envisions the chamber 10 being mounted within an insulat room 25 having walls and ceiling 25. At least a portion o the chamber may be mounted below ground for safety and noi reasons and so that the adjacent earth will act as insulator. Because of the extreme cold that will be pr duced within room 25, adequate insulation is most importan in the exemplary embodiment (FIGS. -1, 4), supercooled ai enters through conduit 29 in the bottom of room 25. I contacts cylindrical wall 11 which becomes a heat transf surface to cause cooling in chamber 10. Air that is heate by the chamber is returned through conduit 23 where it c again be cooled for reentry through conduit 29. Baffle 5 prevents warmed air from flowing back to the cold inl side. Because cylindrical wall 11 is thin and rotating excellent heat transfer is achieved.

As previously stated, one of the important consider tions of vacuum chambers is in dealing with the condens ables. In the present invention, however, the inside o cylindrical wall 11 provides a cold condensing surface o which the vapor freezes uniformly. This layer of ice be comes the ballast to increase the weight on the inner sur face. As it builds up, the rotational speed can continuall be decreased or the vacuum can be increased at consta

BAD ORIGINAL ^f

rotational speed while holding the forces on the wall zero. Alternatively or additionally, lead or other no structural ballast 19 can be attached to the inside of wa

11. Another surprising result is that heat transfer is ma more efficient. At very low pressure, the water vapor other sublimating molecule has a long mean free path. the chamber is stationery, molecules contact the walls £ some bounce back to the product. In the rotating chambe however, when most molecules contact the inside of t rotating cylindrical wall 11, they condense and will n bounce off because of the high induced gravitational forc due to the wall's rotation in addition to providing a co freezing surface for the vapor molecules to stick to. essence, the wall becomes almost an infinite sink because the high g forces and the cold surface.

If the product being processed is food, it would mo likely be undesirable to have the product rotating with t chamber. The high centrifugal forces would crush many fo products especially delicate fruit. Rotating any produ requires more energy, and significant problems occur becau the load would not perfectly balance. Therefore, the pr duct is mounted on an inner member, and the inner member mounted on shaft 12 in a manner such that the inner memb rotates with respect to the end member. Inner member 3 comprises end spoke members 31 and 32 with walls 33, 35, 37 39, 41 and 42 therebetween. The spokes may be replaced by different grid. In the exemplary embodiment, the walls ar not solid but have holes or gaps therethrough so tha migrating vapors can pass through the walls to the inside o cylindrical wall 11. Because the walls are not solid, inne member 30 is sometimes referred to a cage.

It will also be recognized that because the vacuum mean

60 give off heat which is radiated toward the product withi the chamber, the heat will raise the product's sublimatio vapor pressure. Consequently, the increase sublimatio

vapor pressure increases the sublimation mass transfer the vapor state which condenses on the inside of cylindric wall 11. A heat exchanger 68 could direct the heat to t walls of the cage. As previously stated, in the exemplary embodiment t motor 31 drives the shaft causing rotation of the chambe The end spokes 31 and 32 of inner member 30 are mounted the shaft on bearings 45, 46 so that the shaft and thus tϊ ^* end members 20 and 21 and cylindrical member 11 -can rota with respect to the inner member 30. It is also possible have a stationary shaft or shafts (see e.g. FIGS 9 and 10 with the inner member 230 fixed thereto and with the e members 220 and 221 mounted on bearings for rotation wi respect to the stationary shaft. hen the end members 220 , 221 are rotating with respe to the shafts 212 A and 212 B, there will have to be a se between the shafts and the end members to prevent leaka which would destroy the vacuum. Ferrofluidic sea or other sealing means permit rotation of members whi preserving the seal especially at the relatively low angul velocities that will be required in the present inventio Ferrofluidic seals rely on a colloidal suspension magnetic material in a oil. When the oil is subjected to magnetic field, its viscosity rises to act as a seal. Inner member 30 fills substantially the entire volume the chamber as can be seen in FIGS. 1 and 2. By mounti the vacuum means 60 near the bottom of inner member 30 , t center of gravity of the inner member is below the shaft that the inner member does not rotate when the chamber a the shaft . rotate. If the vacuum means 60 were mount closer to the longitudinal shaft 12, friction in bearings and 46 might generate sufficient torque to be transferred inner member 30 to overcome the gravitational forces cause it to rotate. Therefore, the present location of t vacuum pumps, which can be anticipated to be of great density than the food in the remaining portion of the inn

BAD ORIGINAL ^l f OMP

member, yields a low- center of gravity preventing su rotation. in standard vacuum chambers, the gas would first have pass through a condenser to remove the condensables befo reaching the vacuum pump. In the present invention, t wall 11 of the chamber is the condenser. An extern condenser is unnecessary. The conductance term for t condenser can be ignored and less power will be needed f the vacuum pumps. in the first exemplary embodiment, the vacuum means is plurality of vacuum pumps 51 and 52 which are mounted in th vacuum equipment chamber 43 of inner member 30. The vacuu pumps 61 and 52 cooperate with exhaust compressor 53 whic directs the exhaust gases through line 54 and out rotatin seal 65 adjacent shaft 12. Because of the lack o condensables at the vacuum pumps 51 and 62, compressor 6 can exhaust the evacuants from the chamber under relativel high pressure (the pressure will decrease as the pressur within the chamber decreases). Large conduits from the chamber to the vacuum pumps ar not needed because there is no concern about a larg pressure drop from the chamber to the pumps. When couple with the elimination of duplicate conventional condensers the present invention saves substantially in capital an operation costs.

As explained earlier, the food product sublimates, an the vapors condense in the solid phase on the inside of th rotating chamber. This occurs because the heat o condensation from the walls is removed by refrigerating th outer surface by a cold airflow. Although the ice wil serve as a ballast, it is anticipated that too much ice wil eventually build up on the inside of the chamber Therefore, a system for removing excess ice has bee developed. The present invention includes lathe mean adjacent the inside of the cylindrical wall, and lath driving means for moving the lathe along the length of th

cylindrical wall as the wall passes thereover upon rotati of the chamber for removing excess ice from the inside the cylindrical wall. As explained in more deta hereinafter, the ice that is chipped off is caught a ⁵ collected, a batch is then melted and the liquid is pump under high pressure through a rotating seal between t shaft and the end members. Alternatively, ice chips can kept in the solid phase and transported, for example, by auger in batches to the outside through the center shaft. ° in the exemplary embodiment, especially that shown FIGS. 3, 5 and 6, lathe means 90 comprises a cutting bla 91 mounted on cutting head 92 that fits on the lathe shaf 94. The lathe shafts are mounted lengthwise in the chamb at the top and adjacent the inside of the cylindrical, wal ⁵ More than one cutter is shown in ^' FIG. 2 to decrease t length of shafts 94. Sections of lathe shaft 94 can supported on inner member 31. Lathe drive members 93 a mounted in each lathe shaft for movement therein. Ea lathe drive member can be moved in lathe shaft 94 in ma 0 ways, but the exemplary embodiment uses hydraulic pow because of its fine control. As shown ,in FIG. 6, hydraul pump 97 can control the fluid pressure in each lathe sha on either side of lathe drive member 93 to accurate position lathe drive member 93. The lathe drive member 5 magnetically coupled to the head 92 so that when the lat drive member 93 transverses the lathe shaft 94, t magnetism pulls the cutting member along the inside of t cylindrical wall to cut the ice therefrom.

By having a pair of parallel lathe shafts 94, t 0 force on cutter 91 from the rotating ice can be spread ov a greater moment. A single lathe shaft 94 could not circular, because the force from the ice would rotate t support around the lathe shaft, but one noncircular sha could replace the pair of circular shafts shown in t ⁵ exemplary embodiment.

A pair of scrapers 98, attached to support 92, exten

from both ends of the support to remove ice that may form pile up on the lathe shafts 94 after being removed from t inside of cylindrical wall 11. To facilitate removal, t lathe shafts could be Teflon coated. To prevent i buildup, the hydraulic fluid could be heated to warm t lathe shafts to melt any ice. Because there is litt circulation of the fluid, however, in the exempla embodiment, flexible tubes 96 with perforations therethrou are attached to both ends of the lathe drive member 93 a are connected to the hydraulic pump 97. Warmed fluid pumped through tubes 96 to warm the portion of the flu near the cutter where ice buildup will be occurring. As alternative, the lathe drive member 93 could have longitudinal opening therethrough so the hydraulic flu could circulate. If the diameter of the opening controlled, positioning of the lathe drive member can sti be accurately determined.

Lathe drive member 93 should be relatively long to low the force on O-rings 95 from the torque on the lathe dri member.

Cutter 91 is urged about pivot 101 to its uprig position by spring 100 and by the force of the cutt against the ice as the cutter moves from right to left FIG. 6. Stop 99 prevents the cutter from rotating beyo the upright position. After the cutter travels the leng of lathe shaft 94, it should rapidly travel to its initi position where ice will be thickest. Although the blad could stay upright and cut a narrow spiral, the spring 10 allows the blade to pivot counterclockwise as it moves t the right (FIG. 5) .

One of the advantages of the hydraulic system is tha there is no backlash, a common problem in screw drives Although in the present invention, the drive system wa designed to overcome problems if threads of a screw driv became filled with ice, the zero backlash feature is help ful. A screw drive could be used instead in the presen

OM

invention. If so, it could be double threaded with high pitch threads running across the low pitch ones for a fast return trip for the support 92 at the same rate of rotatio The rate of traverse of the lathe can be calculat using certain approximations, but it will ultimately determined by experimentation and will vary depending on t water content of the food being processed. The buildup ra will also be a function of the actual process becaus different processes operate at different pressures, and t pressure and temperature within the chamber affects t sublimation rate.

The formation rate of ice is a function of the amou of product being processed in a given time and the perce of water loss, and the thickness of the ice buildup ^' is al a function of the area of the cylindrical wall. It has be theoretically calculated that if it is desired to proce 5,000 tons of wet product per month, the ice formation ra on the inside of the 60 foot diameter x 40 foot tank wou be approximately 0.31 in/hr with an ice formation rate -about 12,200 Ibs/hr or about 24.5 gallons/minute, assumi that the product is approximately 89% water. If only 2,0 tons of wet product is to be processed each month, the i thickness rate would drop to 0.12 in/hr yielding an i formation rate of approximately 4900 Ibs/hr or 9.8 gallo per minute.

As the ice builds up during processing, the lat translates parallel to the axis of rotation to cut or ch away excess ice, thus keeping the ice thickness at average constant value. Means are provided under the lat means for catching the ice chipped off the cylindrical wal In the exemplary embodiment, this feature is shown at 1 and is intended to run the entire length of the chamber. T ice chips are then transported in the exemplary embodime by means of a conveyor 122 by a piston or to one or mo retorts 121 which can be sealed by cover 125. The ice c be melted by waste heat from heat exchanger 33 (FIG. 4)

change it to the liquid phase in batches, and it can pumped by pump 123 through line 124 under high pressu through a ro'tating seal through end member 20 adjacent sha 12. By having more than one batch retort 121, one could sealed, and the ice melted while the other collects i chips. Pump 123 could be switched to pump from one or t other retort. It would have to have sufficient size to pu all of the ice that is chipped, and that value has be theoretically calculated to be between about 9.8 gallons p minute and 25 gallons per minute. Alternatively, solid i could be transported by conveyor and transported in batch out of the chambers as a solid.

It has been previously calculated that a chamber havi a cylindrical wall 0.5in thick would need a resid ^' ual i layer of about 0.57in for there to be no inward forces n compensated by centrifugal force when the chamber rotating at ach 0.26. The following conditions wou prevail at the inside ice surface: vi.ce ■* 290 ft/sec, N - 92.4 rpm; and ice buildup ra for 3,000 tons of production per month has been calculat to be approximately 0.187 inches per hour.

The cutter lead can be calculated using the followi equation:

(L _c ) = 1 _S / (1 where (L_) = cutter lead (in/rev); l _β = shell length (in); - rotational speed (rev/hr); and T = cutter traverse ti for full length of chamber (hr) (or time to traverse porti of chamber of one of plurality of cutters). The cutter tr verse velocity equals 1 /T (3500) in in/sec. For equali rium, the ice removal rate will equal the ice formati rate, and the ice removal rate equals Dc(Lc)v, where Dc depth of cut (in); and v = surface velocity of cylindric wall (in/sec) .

At equilibrium, D = Tt - - - - - - - - - - - - - (12 where t - ice formation rate (in/hr).

The chip removal rate then becomes Tt(L _{)v an<} 3

equilibrium, this value is equal to the formation rate ice, which is a function of the wet product load and t percentage of water in the food.

It is estimated that an ideal traverse for a single cu ter period would be approximately 0.7 hours with a yieldi a cutter lead of 0.124 in/rev and a depth of cut of 0.13 i

The end members 20 and 21 exert a load in compression cylindrical wall 11. To eliminate the risk of collapse the cylindrical shell in the longitudinal direction due the large external air pressure forces, the wall can constructed as short cylinders such as 110 and 111 attach together by circumferential flanges 112. Flanges 112 a intended to be circumferential with smooth fairings jfco mi imize aerodynamic drag.

The inner member 30 is divided into a plurality of roo 34, 36, 38 and 40 which are separated by walls 33, 35, and 39. These enclosures are where the food to be process is placed. Each of these rooms would be approximately feet tall and slightly less than 40 feet long. Rack which are not shown, could be mounted in the rooms f storage of the products. The rack may have embedded he exchangers to transfer waste heat from pump compartment to the frozen material undergoing freeze drying. Some he energy is used to provide phase change from the solid to t vapor states for the material.

The end members 20 and 21 may include one or mo hatches 130 (Fig. 1) for providing access to the chambe There would also, therefore, be openings such as 135 in cage 30 for providing access to the various rooms. Becau of the large size of the rooms, the product can mechanically loaded therein. An elevator system (not show may be provided for moving the food from level to level the chamber or the room 25. In that regard, stationary moveable platforms 136 could be mounted to outside wall on both sides of the chamber for ease in moving produc into and out of the chamber. After complete processing

6AD ORIGINAL ___^

food, new wet products could be brought in from one side the chamber while processed food was being removed from t other end.

Hydrocarbon Pyrolysis - High Temperature Embodiment. is readily apparent, the chamber shown in FIGS. 9 and shares many features of the chamber of in FIGS. 1 and Chamber 210 which is formed generally of cylindrical wa 211 and end members 220 and 221 rotates on shafts 212A a 212B. To conserve space within processor 210, the sha does not extend through the chamber. The chamber supported on four supports (only three are shown in t drawings) 222, 223 and 224. The shafts are secured at t top of the supports and extend inward to the chambe Although with modifications the shafts could rotate, ^' in t exemplary embodiment, the shaft is intended to be statio ary, and the chamber rotates about the shaft on bearings 2 and 251. Because of the large temperature variations wi cause the chamber to expand and contract longitudinall bearings 250 and 251 are designed to permit transver movement of the bearing along the shaft.

Pyrolysis takes place in bins shown generally in inter nal container 230 (FIG. 10). Although the structure of th internal container will be discussed in more detail herein after, the main supports are shown and include end support or spokes 231, top and bottom walls 241 and 242, and inter nal supporting members 233. End members 231 are attached t the shafts 212A, 2123 and are stationary therewith. Thus chamber 210 rotates around internal container 230. Seal 234 are provided to seal the inside of the chamber fro atmosphere. As shown somewhat schematically, motor 28 acting through pulley 282 a gear train, a transmission o another means rotates chamber 210. An auxiliary motor 28 may be provided to accelerate the chamber and a generato 287 may brake the chamber during cycling so that additiona power may be obtained.

The vacuum pump system 250 in this embodiment may b

si ilar to that shown in the first, it is slightly modifi and includes a plurality of vacuum pumps (only two of whi are shown) 261 and 262 mounted inside sealed compartme 265. The inlets 457 to the vacuum pumps extend through t compartment and the pump exhausts into compartment 265 at near atmospheric pressure. One or more compressors 263 pr ssurizes the output of the vacuum pumps and exhausts t evacuate through narrow tube 254 to the outside of -_ chamber. T e container 230 will be filled with crushed oil shal tar sands or other material to be pyrolyzed, and it must heated to the pyrolytic temperature. In the exempla embodiment, microwave radiation provides the heat energ Although they cannot be seen in FIG. 10, in FIG. 11 the are a plurality of vertical tubular heating members 2 throughout container 230. The space between adjace heating members 270 is filled with crushed shale. Extendi in each heating member are microwave antennas 271, th radiate energy causing the shale to reach desired temper tures. The heating members are actually perforated tub 272 with reflectors 273 mounted behind antennas 271. As t shale is heated and pyrolysis begins to occur, tubes 2 conduct the vaporized gases out of the container and in the space between the container and the chamber. Altern tively, instead of antenna, element 271 could also represe resistance heaters that can be wound around the inside the tubular member 270 for conventionally heating the shal Heat exchangers or other heat source could also be use Other heating systems are also contemplated such as ste pipes or any other conventional heat transfer medium. T size of tubes 271 and their relative spacing will have to determined from experimentation in order to optimize t process. As the heating membe ^' rs are smaller and farth apart, there will be less void area so that more shale c be processed in the container. However, having the heati members farther apart will slow the process.

BAD ORIGINAL

As the pyrolytiσ reaction continues, the hydrocarb vapor formed migrates at molecular speeds to the cylindric wall 211 of the chamber. As set forth in more deta hereinafter, walls 211 will be cooled somewhat so that t gas will condense on the inside of the chamber wall. The are a number of ways in which the condensed petroleum cou be removed from the chamber. In the exemplary embodiment least one outlet tube 283 extends through chamber wall 2 (FIG. 10). The liquid petroleum that forms a film on t inside of ^' the rotating chamber wall 211 is driven centrifugal force through tube 283 into a trough 282 whe it collects and can be pumped away. A valve and a contr system therefor (not shown) is provided to open the val and allow liquid petroleum to flow through tube 283 in trough 282 only when the end of the tube is over the troug Because there will be a pressure differential between t inside and the outside of the chamber of 14.7 psi at s level, the length of the tube will have to be sufficient long so that the head caused by the centrifugal force greater than the pressure forces tending to prevent t petroleum from flowing out of the tube.

The inside end of tube 283 extends into the chamber short distance. Even though the present process i substantially cleaner than many other pyrolytic methods particulate matter will form. It is anticipated that muc of the particular matter will drift through the petroleum t the chamber wall because of the high g forces. Liqui petroleum could be drawn out of the chamber while th particles collected below the top of the tube. Th particles would be allowed to accumulate until thei thickness reached the highest of the top of the tube a which time they could be removed by cleaning the inside o the chamber.

There is also a possibility that some liquid petroleu may fractionalize in which case different components woul form different bands on the inside of the chamber wall. I

O H

this occurs, a plurality of tubes of varying heights coul be used to draw off each fraction, or the tubes could be the same height, and the petroleum could collect and drawn off at different times. The loading and unloading system is designed to rechar the unit quickly. In this regard, end member 221 has one more openings 313 therethrough (FIG. 9) and these are seal by hatches 314. Crushed or rubbelized shale stored in o or more loading bins 310 is fed by gravity or other means movable conveyor 311 which slide on supports 312. When t chamber is to be recharged, it is stopped to align openin 313 with the conveyors. When hatches 314 are opene conveyors 311 are slid through openings 313 , and shale dropped into container 230 within the chamber. The convey may be slowly withdrawn after the right end (FIGS. 8 and 1 of the container is filled to fill the center and left e so that the entire container is relatively uniformly fille Hatches 314 are sealed, the chamber rotates and the shale further heated to pyrolitic temperature. After the reaction is completed, spent shale must removed quickly. In the exemplary embodiment a plurality permanently installed augers 315 at the bottom of t containers are fed by inclined walls 315 and 317. Auge 315 are aligned with openings 313 in chamber end wall 22 and when hatches (not shown) are removed, the augers 315 a coupled to external augers 319 which are movably mounted move into engagement wit ^' augers 315. The augers carry t spent shale to a truck 320 or another conveyor.

It is contemplated that loading and unloading cou occur simultaneously. The augers would remove spent sha until they encountered fresh ore.

It is desirable to preheat the shale to decrease t heating time of the shale within the chamber. Referring FIG. 12, when spent shale is removed from chamber 210, it still very hot, and it is desirable to use this residu heat for heating the next batch of shale ore. There are

BAD ORIG ^I

number of ways in which this residual heat can transferred to the cooler ore, and known heat exchange eould be provided. Line 401 represents the 'heat bei transferred to loading bin 310. In the schematic of FI 12, heat exchanger 325 is shown around loading bin 310, b it is understood that various types of heat exchangers cou be provided. Cart 326 represents ore loaded into t loading bin 310, and cart 327 represents spent shale bei carted away after its residual heat has been removed. Li 402 represents the preheated ore being fed into the chambe and line 403 represents the product being directed storage or further processing facilities.

Some of the gas will not condense on the inside of t chamber but will be removed through the vacuum pumps 260 After passing through line 404, the gas may pass through condenser 405 where the condensable portion may be extract from the noncondensable gas. The condensable portion passe through line 405 to storage or further processing. Much the noncondensable gas is of low BTU quality, but it may b burned, and it is shown being directed through line 407 t turbogenerator 409 for electrical power for powering th electric heaters within the chamber and for rotating it The electrical power is shown to pass schematically throug cable 411, and as shown in FIG. 10, the power passes throug shaft 212B into the chamber. Any power from line 411 use to power or control rotating elements passes through sli rings 412 for power transmission from stationary shaft 212 to rotating chamber 210.

Water or steam could be the heat exchange medium in hea exchanger 325, and cold water can be sprayed on chamber 21 for cooling it and causing the chamber wall to act as condensing surface. oil shale also contains large amount of water which will have to be removed during processing and it would be desirable to save all water for further us in shale processing. Most shale in the United States i found in arid climates. Water vapor which is pumped out o

- ^■ - _. -■ • /-δj JR£

the chamber through line 419 and cooling water vapor that heated through contact with the outside of the chamber wa is compressed in compressor 421 where it passes through he exchanger 422. The path of the spent shale in FIG. 13 indicated at 423, and the compressed water vapor superheated in heat exchanger 422, and it is directed heat exchanger 425 through line 426. The spent shale, whi has lost some of its residual heat in heat exchanger 4 next passes to a solid to solid heat exchanger 428 as sho by line 429. Mined crushed or rubbelized shale ore al passes into heat exchanger 428 as shown from line 431, a the spent shale travels through line 430 to a disposal are The ore that is heated in heat exchanger 428 passes to he exchanger 425 as shown by line 432 where it is heated even higher temperatures by the superheated steam from he exchanger 422. The two stage heat exchanger helps solve t problem that solid-to-solid heat exchanges are inefficien and by utilizing one heat exchanger for .water, the water c be reused in the process. Water partially cooked in he exchanger 425 passes through line 433 to. a condenser cool 434 where the heat can be dissipated to the atmosphere. T cooled water is pumped by means of feed pump 435 throu line 436 as a spray on the outside of the rotating shale a between an insulated housing 438. Thereafter, the wat that is heated from the warmer shale is recycled when it vaporized on the shale.

Referring back to FIG. 12, a condenser 360 is mount within chamber 210 adjacent the rotating shale. it coo the hydrocarbon vapors to assist in condensing them. T heat from the condenser in the form of steam is direct through line 440 into a turbogenerator 441. The spent ste is directed back through line 442 to condenser 360. T additional electricity generated by turbogenerator 441 fed through line 444 to assist in heating the shale duri processing.

The use of much of these heat exchangers will deoend

BAD ORIGΓNAL _OMP I

any analyses. It is noted, however, that many of t proposed shale processes are very wasteful. Those that bu shale waste a substantial portion of the ore and also crea large amounts of pollution. Although the present inventi entails a large, complex processing operation, it intended to be relatively clean, utilizing what might considered waste energy and by-products for further use processing. Insofar as the additional systems are us-' energy and raw materials will be conserved.