WO1998022385A1

WO1998022385A1 - Molten metal reactor and process

Info

Publication number: WO1998022385A1
Application number: PCT/US1996/018749
Authority: WO
Inventors: Donald P. Malone
Original assignee: Ashland Inc.
Priority date: 1996-11-22
Filing date: 1996-11-22
Publication date: 1998-05-28
Also published as: AU1081197A; EP0954511A1; JP2001504431A

Abstract

One or more (preferably three) simple single-chamber crucibles contain molten metal and are successively fed hydrocarbon feed to produce hydrogen, then fed oxygen-containing gas to produce CO, then fed hydrocarbon again, etc. Operation is controlled by a swing valving sequence under timer or composition control.

Description

MOLTEN METAL REACTOR AND PROCESS

CROSS REFERENCE TO RELATED APPLICATIONS Copcnding U.S. patent applications Serial Number 763,097, filed September 20, 1991 , (docket 6391 AUS); Serial Number 08/939,533, filed September 1 , 1992 (docket 6391BUS); Serial Number 08/051 ,753, filed April 22, 1993, (docket 6391MUS): Serial Number 08/165,068, filed December 10, 1993 and is now U.S. 5,435,814, issued July 25, 1995, (docket 643 J BUS); Serial Number 08/303,806, filed Septembei 9, 1994, (docket 6464AUS), respectively.

BACKGROUND OF THE INVENTION

I. FIELD OF THE INVENTION:

This invention relates to the direct gasification of a hydrocarbon into two streams; a relatively pure hydrogen gas-containing stream and a carbon oxide-containing stream, and more particularly to the employment of a plurality of single chamber molten metal reactors and a swing valve system for selectively and sequentially connecting the single chamber reactors to a common hydrogen header and a CO header while supplying a hydrocarbon feed to the single chamber reactors or an oxidant thereto.

II. DESCRIPTION OF THE PRIOR ART:

Typically, molten iron gasifiers disclose either a single reaction zone or two-zone molten iron gasifiers with metal circulation.

U.S. Patents 4,574,714 and 4,602,574 to Bach exemplify the single reaction zone molten iron gasifier, while U.S. Patent 1 ,803,221 to T rer, U.S. Patent 4, 1 87,672 to Razor, U.S. Patent 4,338,096 to Mayes and U.S. Patent 2,647,045 to Rummel exemplify the vo-zone molten iron gasifier concept. While such systems provide reasonable results, none of the systems effect the high purity production of both hydrogen and carbon oxide gases via controlled collection of respective gases at different times from a plurality of single-chamber molten iron reactors or crucibles keyed to the introduction of a hydrocarbon feed and an oxidant to the respective crucibles.

The present invention overcomes the difficulties of prior art single and dual metal bath systems.

BRIEF SUMMARY OF TFIE INVENTION Accordingly, the present invention provides apparatus for direct conversion of a liydrocaibon feed to a gas comprising substantially pure hydrogen and a separate gas stream comprising carbon oxide, said apparatus comprising: a) a plurality of single chamber reactors in the form of closed pressure vessels containing molten metal, b) each reactor including at least one hydrocarbon feed and oxygen feed inlet for feeding a hydrocarbon material and an oxidant to said molten metal and a product gas outlet for removing hydrogen and carbon oxide fiom said reactors, c) a hydrogen header commonly connected to said product gas outlets of said reactors, d) a carbon monoxide header commonly connected to said product gas outlets of said reactors, e) a source of hydrocarbon feed connected to said at least one inlet of each reactor, f) an oxidant source connected to said at least one inlet of each reactor, g) means for sequentially connecting said source of hydrocarbon feed and said oxidant feed source to said at least one inlet of each reactor, and li) means for selectively connecting each reactor alternately to said hydrogen header when said reactor is being fed from said hydrocarbon source and to said CO header when said reactor is being fed from said oxidant source such that a hydrogen-rich stream and a carbon oxide product gas stream are selectively recovered respectively by said hydrogen header and said carbon monoxide header.

DETAILED DESCRIPTION BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a schematic view of a swing valve system for three single chamber molten metal reactors having common headers for hydrocarbon feed and gas product removal with the swing valves downstream of the gas product coolers, allowing the swing valves to operate in a lower temperature environment from that of that of the reactors and forming a preferred embodiment of the invention.

Figure 2 is a plot of the percent purity of hydrogen product gas versus time for the swing system of Figure 1, wherein cyclically, when hydrogen is nearly zero percent, then a CO (of CO and possibly C0₂) is near 100%, and vice versa. Figure 3 is an exploded, perspective view of one of the individual reactors of

Figure 1 showing only the segmented refractories, the molten metal and the refractory bottom and top with inlet and outlet in the lid.

Figure 4 is a more detailed sectional view of a molten metal reactor similar to that of Figure 3 encased in an alloy pressure vessel with rammed thermal insulation filling the annulus between the refractory segments of the reactor and the pressure vessel. A flanged top supports nozzles for the feed inlet and product gas outlet. A packing gland surrounds the inlet lance to provide a pressure-tight fit. Figure 5 is a schematic view of an apparatus forming another embodiment of the invention as described under Example 2 directed to purification systems for the respective product gases.

Tables A, B and C show preferred, more preferred, and most preferred levels of process parameters, feed and product compositions, and reactor configuration.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

FEED MATERIALS: Natural Gas (CH₄), liquified petroleum gas (LPG), propane, petroleum naphtha, light or heavy distillate, vacuum and other resids, solvent deasphalted pitch (SDA), aromatic extracts, FCC slurry oil, trash, garbage, tires, coal, virtually any other hydrocarbon-ct ntaining material.

PRODUCTS:

Products are CO, C0₂, H₂, plus sulfur and other contaminants in feed which may be outputted in slag which can be periodically drained of the molten metal In refineries, sulfrir is preferably outputted as gas in the hydrogen stream and then treated conventionally by the Claus process and the SCOT (Shell Claus Off Gas Treatment) with SCOT (unit).

CONTROLS:

Conventional analog or digital controls may be used, measuring temperature, preferably with optical or infrared pyrometer or protected thermocouple; carbon by spectrometers; level by nuclear radiation and admitting feed, CH^, C0₂, H₂0 to maintain temperature, which must be high enough (e.g., at least 1150 °C to maintain the particular metal carbon composition liquid and dissolved carbon level and H, production within preset limits. Temperature of the molten metal is preferably 1 150 °C tυ 1 00°C, more preferably 1250° to 1500 °C during feed to the reactor or crucible and usually preferably 50 °C to 150°C higher during the oxidation cycle within the single-chamber reactors or crucibles.

The swing can be controlled on the basis of elapsed time, mass fed, percent carbon in molten metal, product purity, or other variables

The present invention is exemplified by the utilization of two or more and preferably three simple, single chamber reactors or crucibles containing molten metal which are sequentially fed hydrocarbon feed to produce hydrogen and then an oxygen- containing gas to produce carbon monoxide. The invention utilizes a swing valving sequence which connects the multiple single chamber crucibles to a hydrogen header for collecting hydrogen when the crucibles are in a hydrogen-producing mode, responsive to the delivery of hydrocarbon feed to such reactor. The invention is further directed to the incorporation of a vent or means for connecting a reactor to the carbon monoxide header during the transition between hydrogen production and carbon monoxide production. Each reactor or crucible preferably consists of a pressure-tight steel housing supporting internally segmented refractories for simplicity in construction and the reduction of thermal expansion effects during reactor operation. Preferably, an inlet lance or sparging tube feeds hydrocarbon material downwardly through a vapor space above the molten metal for discharge at a distal end submerged within the molten metal while the head of the reactor or crucible is provided with a product gas outlet which emits product gases during reactor operation. Preferably, swing valves are located downstream of gas product heat exchangers within such product outlet for lower temperature operation and longer life of the swing valve. The system may be timer operated with switching from hydrogen production to carbon monoxide production every several minutes. Minimum dissolved carbon level during occasional carbon oxidation cycles may be ftirther reduced to also oxidize any sulfur in the melt and to purge sulfur from the melt. Thereafter, vanadium may be periodically purged from the melt by ftirther oxidation. These higher oxidation cycles may be initiated and terminated in response to measurement of sulftir (and/or vanadium) content in the melt or products.

The invention is further characterized by the incorporation of a mixing tank for mixing diluent and pitch equipped with a motor driven mechanical stirrer with a bottom outlet leading to a high pressure pump for varying the viscosity of the pitch fed to the single chamber reactors. Preferably, a source of natuial gas connects via a second molten iron bath penetrating lance, providing temperature control and heat balance to each reactor and compensating for fluctuations in carbomhydrogen ratio of the pitch feed.

The invention is ftirther directed to causing the product gases, i.e., hydrogen and carbon monoxide, flowing outward through the product gas outlet lines to pass through a quench and successively through downstream coolers prior to entry into a knock-out drum having a bottom outlet and a recycle system for the return of condensed water back to the quench. The hydrogen product gas from the knock-out drum may be further fed to a scrubber which removes hydrogen sulfide (H₂S) and emits a substantially sulfur-free hydrogen stream to a downstream compressor system. The sulfur-free hydrogen stream flows to a recycle compressor which increases the pressure approximately one atmosphere and combines new hydrogen with recycle hydrogen and carbon monoxide emanating from a methanol knock-out drum. The combined H₂/CO stream may be directed to a ftirther heat exchanger and through a pair of conversion reactors connected in parallel with the outlet stream from that heat exchanger directed through a further cooler and back to the methanol knock-out drum, from the bottom of which condensed methanol and water are removed as a crude methanol stream. Such stream may then be subsequently subjected to drying and purification. Simultaneously, a reactor or reactors receiving an oxidant and producing a carbon monoxide product gas wliich is then subjected to a water quench and a water cooling p; ocess, with the gas being sent to a water removing drum from which recovered water is recycled through a pump back to the water quench. The discharging carbon monoxide stream from the water removing drum is then sent to a scrubber where the carbon monoxide gas is mixed with hydrogen in a ratio of approximately 2.01 : 1 , which is near stoichiometric.

The present invention is thus directed both to the apparatus for direct gasification of a hydrocarbon material to hydrogen and carbon monoxide gas products using a plurality of single chamber reactors or crucibles and common periodic alternate connections of the multiple reactors to the headers dependent upon whether the hydrocarbon feed is entering the reactor or an oxidant, and the process of producing high purity product gases via such swing system.

The direct gasification hydrogen and carbon monoxide plant of this invention is especially well suited to use a refinery process stream often identified as a solvent deasphalted pitch (SDA bottoms), which is a refinery byproduct stream produced when petroleum residuum is contacted with a light hydrocarbon solvent. The solvent removes the distillate oil from the residuum, leaving a pitch which is high in carbon, low in hydrogen, high in sulftir and high in metals. This stream and other streams having similar properties are present in most refineries, and all these streams can be readily used as hydrocarbon feed in this invention. Still another advantage to the hydrogen plant of this invention is the possibility of adding ethane or methane to produce substantially pure hydrogen. Examples of low hydrogen content carbon are the solvent, deasphalter, the SDA bottoms described above and residuum from the vacuum distillation tower and coal. Hydrocarbons for the purposes of obtaining substantially pure hydrogen are materials consisting of substantially only carbon and hydrogen and an H:C mole ratio of at least 1 : 1, preferably at least one 1 .5: 1 and broadly in the range of 1 : 1 to 4: 1 . Note that methane H:C is 4. 1 ; ethane is 3 : 1 , and octane is 2.25: 1 . Petroleum coke, a suitable feed, is about 0.1 : 1.

According to the invention, two or more (preferably three) simple single- chamber crucibles contain molten metal and are successively fed hydrocarbon feed to produce lvydrogen, then fed oxygen-containing gas to produce CO, then fed hydrocarbon again, etc. Their operation is controlled by a swing valving sequence which connects them to a hydrogen header when they are producing hydrogen and to a CO header when they are producing CO, and possibly to a vent (or to the CO header) during the transition between FL production and CO production (see Figure 2). Each crucible 2 (Figure 3) preferably is in a pressure-tight steel housing 4. uses segmented refractories 6 for simplicity in construction and reduction of thermal expansion effects and has an inlet lance 30 (sparging tube) for feeding hydrocarbon and an outlet 32 which emits product gases. Both an inlet for feeding hydrocarbons and an outlet which emits product gases are preferably located in the head 8 of each crucible 2, coupled to the body of the crucible by tie rods 9, Figure 4. Swing valves are preferably located downstream of product heat-exchangers for lower temperature operation. Extra oxidation to reduce further dissolved carbon level during occasional cycles can be provided to oxidize any sulfur in the melt and purge sulfur from (he melt. Then vanadium can be periodically purged from the melt by still further oxidation to oxidize the vanadium. Inorganic materials contaminating the hydrocarbon feed will usually form a slag layer floating on top of the molten metal.

The following table gives some of the reactions occurring in the various molten metal layers: Possible Reactions Occurring in An}' Slag Layer During the Carbon Cycle and

Possibly During the Oxidation Cycle:

CaO + FeS + C -> CaS + Fe + COT CaO + FeCl ₂ + C -> CaCl ₂ + Fe + COt

Reactions Occurring in the Molten Metal During the Carbon Cycle:

C + 3Fe --> Fe₃C

C„H_m 3ιιFe --> nFe₃C + m/2H₂l

C_kH_mN_n +^■ 3kFe ~> kFe₃C +^• m/2H₂T ^•+ n/2N₂l C_LH_mO_n + 3 (k-n) Fe -- (k-n)Fe₃C + M/2H₂t + nCOT UA +- (3k- n) Fe -— kFe C + m/2H₂l + nFeS or nH₂S t C_kH_ιnCl_n +- 3kFe ~> kFe₃C + m/2H₂l + n/2Cl₂ϊ

Reactions Occurring in the Molten Metal During the Oxidation Cycle:

2Fe₃C + 0₂ -> 6Fe + 2COT Fe C + H,0 -- 3Fe H₂1 + COT

EXAMPLE 1 (Production o/H₂ and CO according to the inv ntion)

Figure I shows schematically a swing valve system indicated generally at I for three molten metal reactors 10, 12 and 14, respectively, which are successively connected to a hydrocarbon feed source 16, in this case feeding solvent deasphalted pitch (SDA) of the analysis shown in Table D, first four columns. Various process parameters, feed and product compositions, and reactor parameters are set forth in Tables A, B and C, respectively.

l\5 I

215 tons per day ( 7,916 pounds per hour) of this solvent deasphalted pitch 16 are fed first to reactor 10 through inlet valve 20 and down through a penetrating lance 30 into molten iron 40. Care is taken that the lance 30 is insulated and the flow rate is sufficient so that the pitch reaches its decomposition temperature only when it is in or veiy close to contact with the molten iron in the reactor. This provides instant dissolving of the carbon released from the pitch and avoids coke or carbon deposits or soot in the reactor gas phase. The pitch decomposes into products as shown in the last five columns of Table D, entitled "Product Gas". These products are released through outlet line 50, cooled in a high pressure boiling-water cooler 60 and thereafter ftirther cooled in a low pressure boiling water cooler 70 so that their temperature is reduced to about 275 °C when they flow through swing valve 80 which is in the open position during this portion of the cycle. The product hydrogen is as shown in Figure 7 and described in Table D and moves into hydrogen header 100 for export. Simultaneously, the second reactor 12 is fed substantially pure cryogenic air separation plant oxygen through oxygen inlet valve 112. The oxygen contacts the carbon dissolved in the molten iron in reactor 12, oxidizes it primarily to CO which is expelled through outlet line 52 and passes successively through heat exchangers 62 and 72, (corresponding to heat exchangers 60 and 70) and travels through CO valve 122 (hydrogen valve 82 remains closed) into the CO header 130 where it is exported for conversion to C0₂ or use in chemical synthesis. Again, all purities and flow rales of CO are shown in Table A, as are temperatures, pressures, etc.

After a preset time, about 3 minutes in this example, the valves are reversed with pitch inlet valve 20 closing on reactor 10 and oxygen inlet valve 110 opening substantially simultaneously with the closure of oxygen inlet valve 1 12 and the opening of the pitch inlet valve 22 on reactor 12. The exact sequencing and the pause between opcning and closing, together with any optional purging may be varied as convenient for best production of highest quality gases.

During this entire sequence, reactor 14 remains in stand-by. During stand-by, reactor 14 could be rebuilt by replacing its refractories, lance, etc. The stand-by condition is rotated among reactors 10, 12 and 14 approximately daily or as needed. It should be apparent that various control systems may be employed for operation of the swing system including periodic opening and closing of swing valves 80, 82, 84 and 120, 122, 124 associated respectively with hydrogen header 106 common to all three reactors 10, 12 and 14 and carbon monoxide header 108 common to the same reactors. In the illustrated embodiment of Figure 1 , an electrical timer 160 connects to an electrical source via a pair of leads 162 and includes outlet control leads 169, 166, 168, 1 70, 172 and 174 which lead directly to electromagnetic swing valves 80, 120, 82, 122, 84 and 124, respectively. The timer 160 includes switching means for switching the valves from closed to open, and vice versa, in the manner described previously such that when the reactors 10, 12 and 14 are being supplied from hydrocarbon feed source 16 during an initial portion of the cycle and hydrogen gas is being produced, the swing system ensures connection between the hydrogen header 106 and such reactors. In a second portion of the cycle, the reactors are receiving an oxidant from a oxidant supply 18, the result of which is to create a carbon monoxide or carbon dioxide off-gas which escapes from the top of the reactor in the space above the molten iron bath 40 through the various gas product outlets 50, 52, 54 and being fed via now energized and open swing valves 120, 122 and 124, as the case may be, to the carbon monoxide header 108 for escape via line 130. By reference to Figure 2, it is evident that for maximum purity of the hydrogen in the single cycle of operation for each of the reactors 10, 12, 14, the valves 80, 82, 84, 120, 122, and 124 are switched so that the flow of gas is diverted to the carbon monoxide manifold where the carbon monoxide level is 25% of its maximum equilibrium value and the gas diverted to the hydrogen manifold where its level is 75% of its maximum equilibrium value.

It is preferable to either shut off the hydrogen and carbon monoxide headers from the reactors during the major extent of operation of the reactors, or to vent the interior of those reactor chambers to the atmosphere. Referring back to Figure 1 , there is a dotted line showing of both the vent lines 140, 142, 144, the open/close valves 146, 148 and 150 for respective vent lines, with those vent lines being connected to respective product gas outlet lines 50, 52, 54 intermediate of the reactors 10, 12 and 14 and the swing valves for controlling system operation at 80, 82, 84, 120, 122 and 124. Further, in the illustrated embodiment as an alternative, timer energized lines 180, 190 and 1 2 connect the timer to the electroma netically operated open/close valves 146, 148 and 150 respectively.

This is only one illustrated embodiment of a control system for operating the swing valve of the plurality of molten metal reactors. Preferably two are operating in alternative modes, while the third is shut down for repair. A different control system may be employed using sensors for sensing the particular gas content within the reactor chambers above the level of the molten metal 40 or within the gas product discharge lines. Upon sensing a particular gas level of hydrogen or a carbon oxide, the swing valves are periodically switched from open to closed, or vice versa, corresponding to whether the cycle of operation for each reactor is in the hydrocarbon feed and thus the production of hydrogen part of the cycle or the feed of an oxidant and the production of carbon oxide off-gas. By using the vent lines 140, 142, 144, over a major time extent of the cycle of operations for the individual reactors, the quality of the hydrogen and carbon oxide streams is ensured. Alternatively, it may be desirable to simply purge the interior chambers of reactor vessels between the hydrogen production and carbon oxide portions of the reactor cycle. Similarly, the system may be operated at 400 psi with high pressure pumps for feed, and optionally may have a diluent feed system.

EXAMPLE 2 (Purification of product streams)

Figure 5 shows mixing tank 200 for mixing diluent and pitch and equipped with stirer and bottom outlet 204 leading to high pressure pump 230, a vertical plunger pump manufactured by Ingersol Rand Company and diluent tank 210 feeding to mixing tank 200 via line 206 through pump 220 or varying the viscosity of the pitch fed through high pressure pump 230. Table E sets forth various operating parameters for the purification system of Example 2, Figure 5.

o The pump communicates through a line 232 to molten metal lance 30 as, for instance in molten metal reactor 10, Figure 1. A source of natural gas 234 connects with a second lance 32 (the same lance as used for the pitch may alternately be used) and enters into the molten metal bath M in reactor 10. This natural gas is used for temperature control and heat balance and can compensate for fluctuations in carbon: hydrogen ratio in the pitch feed. Product gases (hydrogen H₂ at this point in the cycle) flow outward through product gas outlet line 250 through quench 252 and successively through coolers 260 and 270 (approximately the same as coolers 60 and 70 in Fig. 1 , Example 1 ) into a knockout drum 272 which has a bottom outlet and recycle system 276 including a recycle line 278 and a pump 274 for return of condensed water back to quench 252. Hydrogen from knockout drum 272 is fed via line 282 to a scrubber means 280 which removes hydrogen sulfide (H₂S) and emits a substantially sulfur-free hydrogen stream through line 284 to compressor 290 which has an outlet pressure of approximately 8.3 million pascals ( 1200 psig). The sulfur-free hydrogen stream then flows via line 286 into recycle compressor 300 which increases the pressure approximately one atmosphere and combines the new hydrogen with recycle hydrogen and CO coming from methanol knockout drum 310 via line 292. The combined H₂/CO stream flows into heat exchanger 320, then simultaneously through methanol conversion reactors 330 and 335 which are in parallel. The outlet stream from heat exchanger 320 is sent through cooler 340 via line 322 and back to knockout drum 310 from the bottom of which condensed methanol and water are removed by line 312 as a crude methanol stream for drying and further purification if necessary.

Simultaneously, reactor 12 (shown in Figure 1 , but not shown in Figure 5) provides CO from crucible 12 to water quench 400, Fig. 5, which leads into steam cooler 410 and onto water cooler 420, then into a water removing drum 430, from which water is recycled by line 432 tlirough pump 435 back to water quench 400. The resulting CO stream moves from water removal drum 430 to a scmbber means 280 (described previously) via line 434 where it mixes with the hydrogen. The hydrogen: CO ratio is approximately 2.01 : 1, that is, approximately stoichiometric.

Reference to documents made in the specification is intended to result in such patents or literature being incorporated by reference.

What is claimed is:

Claims

CLAIMS ] . Apparatus for direct conversion of a hydrocarbon feed to a gas comprising substantially pure hydrogen and a separate gas stream comprising carbon oxide, said apparatus comprising: a) a plurality of single chamber reactors in the form of closed pressure vessels containing molten metal, b) each reactor including at least one hydrocarbon feed and oxygen feed inlet for feeding a hydrocarbon material and an oxidant to said molten metal, and a product gas outlet for removing hydrogen and carbon oxide from said reactors, c) a hydrogen header commonly connected to said product gas outlets of said reactors, d) a carbon monoxide header commonly connected to said product gas outlets of said reactors, e) a source of hydrocarbon feed connected to said at least one inlet of each reactor, f) an oxidant source connected to said at least one inlet of each reactor, g) means for sequentially connecting said source of hydrocarbon feed and said oxidant feed source to said at least one inlet of each reactor, and h) means for selectively connecting each reactor alternately to said hydrogen header when said reactor is being fed from said hydrocarbon source and to said CO header when said reactor is being fed from said oxidant source such that a hydrogen-rich stream and a carbon oxide product gas stream are selectively recovered respectively by said hydrogen header and said carbon monoxide header.

2. The apparatus of claim 1 wherein said means for selectively connecting each reactor alternate!} to said hydrogen header and said carbon monoxide header comprises at least one swing valve within each gas outlet of each reactor and control means for controlling said swing valve.

3. The apparatus of claim 1 with means for sensing predetermined levels of hydrogen aiivl a carbon oxide within said gas product outlet of said reactors, and means connected to sπid sensing means and responsive to sensing a predetermined level of hydrogen within a given outlet for connecting said given outlet to said hydrogen header, and means connected to said sensing means and responsive to sensing a carbon oxide at said predeteπnined level within a given gas product outlet for connecting said given gas product outlet to said carbon monoxide header and for terminating the connection of said given gas product outlet to said hydrogen header.

4. The apparatus of claim 1 further comprising vent means operatively coupled to each, reactor for venting the interior of the reactor during a transition between the hydrocarbon feeding and oxidant feeding of said reactor or operatively coupled to each product gas outlet downstream of said reactors.

5. A process for reacting a hydrocarbon feed in a molten metal bath to sequentially provide substantially pure hydrogen and carbon oxide product gases, said process comprising in combination the steps of: a) providing at least one of molten metal baths within single chamber pressure vessels; b) sequentially feeding a hydrocarbon feed and an oxidant feed said molten metal bath sequentially causing carbon to be dissolved in said molten metal bath and hydrogen gas to be released therefrom; c) a carbon oxide gas to be created therein and released therefrom; d) periodically and sequentially removing substantially pure hydrogen gas from each of said pressure vessels during time periods when said molten metal bath is being fed with said hydrocarbon feed; and e) removing substantially pure carbon oxide gas during different time periods when said molten metal bath is being fed said oxidant.

6. The process of claim 5 wherein at least two molten metal bath reactors are used, with each having at least one feed inlet and at least one product gas outlet, a hydrogen header commonly connected to said at least one product gas outlets of each of said reactors, a carbon monoxide header commonly connected to said at least one product gas outlet of each of said reactors, swing valves within said product gas outlets for each of said vessels for selectively connecting said product gas outlets to and disconnecting said product gas outlets from said hydrogen header and said carbon monoxide header, and wherein said process further comprises control means for periodically and sequentially operating said swing valves.

7. The process of claim 6, wherein a timer controls said swing valves.

8. The process of claim 6 wherein at least one gas composition controls said swing valves.

9. The process of claim 5, further comprising the step of at least periodically venting the interior of said reactor.

10. The process of claim 5, further comprising at least one of: s a) mixing a pitch and a diluent prior to feeding said hydrocarbon material to said plurality of reactors, thereby varying the viscosity of the pitch being fed; b) feeding a natural gas into the molten metal baths of said reactors for accomplishing temperature control and heat balance and compensation for fluctuations in carbon :hydrogen ratio of the pitch feed; and c) quenching and successively cooling the flow of hydrogen through said product gas outlet of said reactors while feeding hydrocarbon material feed into said molten metal of said reactors and removing any water content of said hydrogen within a knockout drum and recycling any condensed water from said knockout drum back to the hydrogen gas quench.