Fe + H2O = FeO + H2

The above equation tells us that with steam and hot or molten iron we can make H2 with rust being the byproduct. This rust can be converted back to iron. Check out the below links for more information.

A seven page pdf file called HYDROMAX - BRIDGE TO THE HYDROGEN ECONOMY

Alchemix home page: ALCHEMIX HOME PAGE

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<p>Peter wrote:<br /> Alchemix first shows up in my extensive Hard Drive archives in Nov 2001 --<br /> when they were proposing using molten zinc metal baths -- which I thought<br /> was a very ingenious system indeed.</p> <p>Ergo -- I researched it in much greater depth -- back "when"</p> <p>Those other replies I posted are but a very few examples of where that<br /> research led me.</p> <p>My interest in this process comes from an old past "experience"</p> <p>Around 1978 or so one of the industrial scrap yards I sourced "materials"<br /> from was situated in an old abandoned steel mill near the Verdun Canal.</p> <p>The plant was in full activity in the from the late 1800's to the early<br /> 1900's -- O believe the great depression was it's final death blow.</p> <p>The "ruins" were fascinating and highly interesting.</p> <p>The owner of this scrap yard became a close acquaintance -- and one day<br /> supplied me with the address of the last plant engineer -- who still lived<br /> about 3 miles from this site.</p> <p>In 1978 he was 84 years of age -- but once I showed interested in the old<br /> mill -- he became amazingly 'sharp'!</p> <p>They had large underground "fire brick checker heat exchangers that could<br /> be shifted in direction flow -- thus heated -- then heat recovered.</p> <p>They also baked commercial construction bricks in the chambers.</p> <p>They used the producer gas which was by product of the bessemer steel<br /> making process in this manner.</p> <p>It was burned in a tall vertical "kiln" -- which was the heart of a<br /> reversible -- or two stage process.</p> <p>The bottom part was where producer gas and air were encouraged to combust -- </p> <p>Directly above the combustion chamber were layers of heavy iron gratings --<br /> above that were very high temperature (but less than 5 psi pressure!!)<br /> steam super heaters -- and above that was a simple low pressure fire tube<br /> boiler -- with a steam regulator -- max pressure was 100 psi -- and that<br /> was reduced to feed the superheaters at 5 psi (A steam pressure regulator<br /> is often simply a Tempering device -- where a little water is mixed in --<br /> you end up with more volume -- lower pressures -- dry steam --</p> <p>The exhaust from this kiln was in that mode ported in to the underground<br /> checker heat exchanger/brick baking works.</p> <p>They produced a lot of H2 -- had a good market for it -- though I never<br /> asked more about that part (maybe Zeppelins though??)</p> <p>Here is how the old engineer set up to make it "then" --</p> <p>First they burned producer gas -- till the thick layer of iron grates<br /> reached 2200 F or more -- and the boiler boiled hard. Balancing out (due to<br /> it's design capacity -- with a good head of steam under 100 psi but with a<br /> large waterr volume.</p> <p>The hot exhaust gases went down to the heat exchangers --- giving up their<br /> highest heat - -then being exhausted -- (Baking new brick also -- a little<br /> "side-line")</p> <p>Then the flow was reversed and switched -- the produce gas combustion and<br /> air was shut down -- the heat exchanger direction was reversed -- ambient<br /> air blown through it being heated and then fed into the bottom of the kiln<br /> to be mixed with very super heated steam.</p> <p>The low temperature low pressure super saturated steam was released into<br /> the super heaters which were directly above the 2200 F plus thick cast iron<br /> grates - -where radiant heat rose the temperatures of that steam to over<br /> 1800 F --</p> <p>That steam was fed back into the bottom of the kiln with the super heated<br /> air and rose up to impinge on the cast iron grates --</p> <p>The reaction was steam -- hot iron -- iron Oxidizing to magnetic Oxide --<br /> steam becoming H2 gas.</p> <p>That off mixture then went into another underground complex where<br /> relatively pure H2 was isolated from the air/H2 mix.</p> <p>Once the iron grids cooled to much -- the system was reversed to run on the<br /> producer gas to heat everything back up again. </p> <p>The producer gas combustion produce much very hot CO2 which reduced the<br /> magnetic oxide coatings on the iron grates back to iron -- and the process<br /> then would flip again --</p> <p>Another version they operated was when they got contract to make "black<br /> iron piping" -- the black iron being iron with a layer of magnetic oxide -<br /> -which resists all further corrosion.</p> <p>Well -- if you replace the source of the producer gas from being the by<br /> product of a bessemer furnace to a biomass gasifier --</p> <p>And remember -- this all back turn of 1800's/1900's</p> <p>Jeff -- you probably could build a small version of that process in your<br /> own back yard!</p> <p>Oh -- I did plumbing jobs in old Montreal where I took out steam for heat<br /> delivery piping -- those old very low pressure systems (3 psi max) which<br /> pipe was well over 100 years old -- and that same "Black" pipe described<br /> above -- and totally not corroded at all -- just like new -- as the day it<br /> was made.</p> <p>Peter -- Belize</p>

<p>Peter found:<br /> DETAILED DESCRIPTION OF THE INVENTION </p> <p>The invention provides process and apparatus for producing simultaneously a<br /> high-purity, high-pressure hydrogen-rich gas stream and a high-purity,<br /> high-pressure carbon monoxide-rich gas stream separately and continuously<br /> using a molten metal gasifier that contains at least two zones, a "feed<br /> zone" and an "oxidation zone", (or in a saving embodiment, a feed mode and<br /> an oxidization mode) together with necessary ancillary equipment. Each zone<br /> (mode) preferably operates at a pressure above 5 atmospheres absolute and<br /> contains a bath of comprising molten iron and, possibly, other molten<br /> metals, such as copper, zinc, chromium, manganese, nickel or other meltable<br /> metal in which carbon is soluble. Preferably the bath contains at least 30<br /> percent iron by weight. Depending upon the feed, the bath may also contain<br /> slag components which, if present, preferably form a separate phase. </p> <p>In the feed zone, a hydrocarbon-containing feed in the form of a gas,<br /> liquid, solid or mixed phase, e.g., a solid-liquid slurry or atomized solid<br /> or liquid is introduced below the surface of the molten metal bath so that<br /> the hydrocarbon feed comes into intimate contact with the molten metal. The<br /> feed is introduced beneath the surface of the molten metal by a submerged<br /> tuyere or lance or by high-velocity injection from a lance above the bath,<br /> thereby ensuring that substantially complete chemical reactions and<br /> substantially complete conversions to hydrogen and carbon are achieved. It<br /> has been shown that high-purity hydrogen, defined as having a composition<br /> very close to thermodynamic equilibrium, can be obtained in this manner.<br /> The high-purity hydrogen thus formed leaves the feed zone as a<br /> high-pressure hydrogen-rich gas, while the carbon dissolves in the molten<br /> metal. Any nitrogen compounds present in the hydrocarbon feed will<br /> decompose to form molecular nitrogen and leave as an impurity in the<br /> hydrogen-rich gas. The hydrocarbon feed should contain a minimum of<br /> moisture and other oxygen-containing compounds since these compounds will<br /> decompose to form oxygen, which in turn will react with dissolved carbon to<br /> form carbon monoxide, an undesirable impurity in the hydrogen-rich gas. </p> <p>The molten metal from the feed zone containing higher levels of dissolved<br /> carbon then enters the oxidation zone where oxygen, air, oxygen-enriched<br /> air or other suitable oxygen-bearing stream is introduced. The<br /> oxygen-bearing stream is introduced beneath the surface of the molten metal<br /> by a submerged tuyere or lance or by high-velocity injection from a lance<br /> from above the bath. A portion of the dissolved carbon reacts with the<br /> oxygen to form carbon monoxide. It has been shown that high-purity carbon<br /> monoxide, defined as having a composition very close to thermodynamic<br /> equilibrium, can be obtained in this manner. The high-purity carbon<br /> monoxide thus formed leaves the oxidation zone as a high-pressure carbon<br /> monoxide-rich gas separate from the hydrogen-rich gas produced in the feed<br /> zone. The molten metal from the oxidation zone which has a lower<br /> concentration of carbon re-enters the feed zone where the carbon level is<br /> increased again. </p> <p>Both molten metal zones are operated at elevated pressures, preferably<br /> between 5 and 100 atmospheres absolute, which results in the production of<br /> the hydrogen-rich and carbon monoxide-rich gases at elevated pressures,<br /> thereby eliminating the need for costly compression of the gases to<br /> industrial operating pressures, as mentioned earlier. By reducing gas<br /> hourly space velocity (GHSV), elevated pressures also result in smaller<br /> equipment and piping for the process including all downstream equipment and<br /> in reduced dust carryover from the feed and oxidation zones and, by Stoke's<br /> Law, elevated pressures reduce deleterious dust carry-over or "fuming". </p> <p>A significant portion of the oxygen left in the molten iron as it re-enters<br /> the feed zone will react with carbon from the hydrocarbon feed to form<br /> carbon monoxide, which then becomes an impurity in the hydrogen-rich gas<br /> stream. Thus, it is important to operate the process in such a manner that<br /> there is a minimum of oxygen present in the molten iron when it re-enters<br /> the feed zone. As a minimum, the molten metal will contain dissolved oxygen<br /> based on the equilibrium with carbon monoxide gas. In addition, as an<br /> oxygen-rich stream is introduced into molten metal, there is a tendency for<br /> the oxygen solubility limit of the molten metal to be exceeded immediately<br /> at the interface between the oxygen-rich stream and the molten metal, which<br /> results in the formation of a separate iron oxide phase at the interface.<br /> This iron oxide phase will be readily dissolved by surrounding molten metal<br /> and not accumulate in the molten metal bath provided the overall oxygen<br /> concentration of the molten metal bath is below the oxygen solubility<br /> limit. If the overall equilibrium oxygen concentration of the molten metal<br /> bath exceeds the solubility limit, however, the separate iron oxide phase<br /> will tend to accumulate to significant levels. Then, when the molten metal<br /> containing significant quantities of this iron oxide phase re-enters the<br /> feed zone, much of this iron oxide phase will react with carbon from the<br /> hydrocarbon feed to form a substantial quantity of carbon monoxide, which<br /> will contaminate the hydrogen-rich gas being produced. Accumulation of<br /> significant quantities of a separate iron oxide phase also substantially<br /> increases the attack of the refractory walls in the vessels holding the<br /> molten metal since a separate iron oxide phase can be very aggressive<br /> toward refractory. Thus, the oxygen concentration in the molten metal must<br /> be controlled so that it does not exceed its solubility limit. </p> <p>When molten iron is in equilibrium with carbon monoxide gas (formed in the<br /> oxidation zone), it has been shown that carbon and oxygen exist in the<br /> molten iron at equilibrium concentrations which can be determined by the<br /> equation: ##EQU1## where: K is an equilibrium constant that varies with<br /> temperature, dimensionless </p> <p>[C] is the concentration of carbon in molten iron, weight percent </p> <p>[O] is the concentration of oxygen in molten iron, weight percent </p> <p>P.sub.CO is the partial pressure of carbon monoxide, atmospheres absolute<br /> (ata) </p> <p>T is the temperature, .degree. K. </p> <p>The solubility limit of oxygen in molten iron can be described by: </p> <p>log [O.sub.solubility limit ]=-6320/T+2.734 (2) </p> <p>where: </p> <p>[O.sub.solubility limit ] is the concentration of oxygen in molten iron at<br /> its solubility limit, weight percent </p> <p>Thus, at a given temperature, T, the minimum concentration of carbon<br /> required in the molten iron to ensure that the equilibrium oxygen<br /> concentration in the molten iron does not exceed the oxygen solubility<br /> limit can be described by the equation: ##EQU2## </p> <p>At 1600.degree. C., for example, the solubility limit of oxygen based on<br /> Equation (2) is 0.229 weight percent in molten iron. Using Equation (3) at<br /> this temperature, the minimum carbon concentrations as a function of<br /> pressure required to prevent the equilibrium oxygen concentration from<br /> exceeding 0.229 weight percent are calculated as follows: </p> <p> ______________________________________<br /> CO Partial Min. Carbon<br /> Pressure, ata Conc., wt %<br /> ______________________________________<br /> 0.01 0.00009<br /> 0.1 0.00088<br /> 1 0.00884<br /> 5 0.04422<br /> 10 0.08844<br /> 20 0.17688<br /> 50 0.44221<br /> 70 0.61910<br /> 100 0.88443<br /> 150 1.32665<br /> ______________________________________</p> <p>Similar relationships can be determined for different temperatures and for<br /> molten metal baths which contain iron mixed with other metals. </p> <p>In commercial steel-making practices, it is common to operate at a pressure<br /> of one atmosphere and, in a few processes, under vacuum. As shown by data<br /> above, when operating at carbon monoxide partial pressures of one<br /> atmosphere or below, relatively low concentrations of carbon can be<br /> achieved without reaching the oxygen solubility limit. For example, at<br /> 1600.degree. C. and one atmosphere, the carbon concentration must fall<br /> below 0.0088 weight percent before the solubility limit of oxygen is<br /> exceeded and a separate iron oxide phase starts to accumulate. </p> <p>When operating at elevated pressures, on the other hand, control of minimum<br /> carbon levels becomes much more critical. At 1600.degree. C. and 100<br /> atmospheres of pressure, for instance, the oxygen solubility limit is<br /> reached when the carbon level reaches about 0.88 weight percent, which is<br /> 100 times higher than for one atmosphere of pressure. </p> <p>Thus, in the present invention, the carbon concentration in the molten iron<br /> leaving the oxidation zone and entering the feed zone is controlled above<br /> the value determined by Equation (3) at elevated pressures to prevent the<br /> equilibrium oxygen level from exceeding its solubility limit and causing<br /> the accumulation of a separate iron oxide phase, which would result in the<br /> excessive formation of carbon monoxide in the feed zone and excessive<br /> contamination of the hydrogen-rich gas. </p> <p>The carbon concentration in the molten metal bath leaving the feed zone, on<br /> the other hand, is controlled at a higher concentration in order to<br /> minimize the quantity and circulation rate of molten metal required in the<br /> system. The economics of the process are better when the differential in<br /> the carbon concentrations between the feed zone and the oxidation zone are<br /> higher. Thus, the carbon concentration in the molten metal leaving the feed<br /> zone should be maximized, although the concentration must be kept below the<br /> carbon solubility limit (which is in the range of 4-5 weight percent in<br /> molten iron) in order to minimize unreacted carbon and hydrocarbon feed<br /> from leaving the molten metal as dust and lower molecular weight<br /> hydrocarbons in the effluent gas. </p> <p>This invention also includes having the hydrogen-rich and carbon<br /> monoxide-rich gases flow from the molten metal zones through separate<br /> product gas lines and pass through successive downstream coolers and dust<br /> removal systems to prepare the gases for use by industrial processes. </p> <p>Suitable feeds for the process include hydrogen- and carbon-containing<br /> materials selected from the group consisting of: light gaseous hydrocarbons<br /> such as methane, ethane, propane, butane, natural gas, and refinery gas;<br /> heavier liquid hydrocarbons such as naphtha, kerosene, asphalt, hydrocarbon<br /> residua produced by distillation or other treatment of crude oil, fuel oil,<br /> cycle oil, slurry oil, gas oil, heavy crude oil, pitch, coal tars, coal<br /> distillates, natural tar, crude bottoms, and used crankcase oil; solid<br /> hydrogen-and carbon-containing materials, such as coke, coal, rubber, tar<br /> sand, oil shale, and hydrocarbon polymers; and mixtures of the foregoing. </p> <p>A portion of the hydrogen-rich gas or carbon monoxide-rich gas may be<br /> recycled in the process to facilitate feeding hydrocarbons to the feed zone<br /> or feeding an oxygen source to the oxidation zone or to promote mixing or<br /> movement of the molten metal. </p> <p>When feeding a heavier liquid or solid hydrocarbon to the feed zone and<br /> feeding oxygen to the oxidation zone, the overall process of converting the<br /> feedstock to hydrogen-rich and carbon monoxide-rich gases is exothermic.<br /> Thus, it becomes necessary to moderate the temperatures of the process. In<br /> the present invention, this is accomplished by (a) adding light gaseous<br /> hydrocarbons to the feed zone, (b) adding carbon dioxide to the oxidation<br /> zone, (c) adding steam to the oxidation zone or (d) diluting the oxygen<br /> with air. In each case, sufficient material is added to achieve an overall<br /> adiabatic operation and stable operating temperatures. Case (a) or (b) is<br /> preferred when the objective is produce two high-purity gas products. Case<br /> (c) or (d) introduces impurities to the carbon monoxide-rich gas and is<br /> practical only if the purity of the carbon monoxide-rich gas is not critical. </p> <p>When a hydrocarbon feed containing sulfur compounds is fed to the feed<br /> zone, the sulfur compounds will decompose and elemental sulfur thus formed<br /> will dissolve in the molten metal. In conventional practice, a fluxing<br /> agent, such as calcium oxide, is added to the bath to react with the<br /> dissolved sulfur and produce a sulfide, which forms a slag phase which<br /> tends to float on the top of the molten metal. The slag is removed<br /> continuously or intermittently by tilting the vessel and pouring out the<br /> slag or by allowing the slag to flow through a tap hole in the side of the<br /> vessel. Pouring or tapping slag is difficult to practice in a vessel<br /> operating at elevated pressures. To handle sulfur in hydrocarbon feeds<br /> containing high levels of sulfur of up to 4 weight percent or more requires<br /> the use of large amounts of fluxing agents and produces large amounts of<br /> slag which must be disposed of safely. Thus, it is becomes very expensive<br /> to handle hydrocarbon feeds containing high levels of sulfur using<br /> conventional practices. </p> <p>As an added feature of the present invention, the sulfur in the hydrocarbon<br /> feed is processed without the use of slag. Dissolved elemental sulfur (from<br /> the hydrocarbon feed) is allowed to build up in the molten metal bath to an<br /> equilibrium level and to react with hydrogen dissolved in the bath (also<br /> from the hydrocarbon feed). Hydrogen sulfide is formed and leaves the<br /> molten metal bath in the gaseous effluents, primarily the hydrogen-rich<br /> gas. The concentration of elemental sulfur dissolved in the molten metal<br /> bath will reach an equilibrium level such that the rate of sulfur leaving<br /> the molten metal bath as hydrogen sulfide is equal to the rate of sulfur<br /> entering the molten metal bath with the feed. The equilibrium concentration<br /> of sulfur in the molten metal is a function of the carbon level present. By<br /> achieving a relatively high level of carbon in the molten metal leaving the<br /> feed zone, the equilibrium level of sulfur in the bath can be minimized.<br /> Sulfur compounds other than hydrogen sulfide, such as carbonyl sulfide and<br /> carbon disulfide, may also be formed and leave in the products gases,<br /> especially in the carbon monoxide-rich gas. The product gases may be fed to<br /> conventional scrubbers to remove the hydrogen sulfide and other gaseous<br /> sulfur compounds, thereby recovering the sulfur for reuse in industry and<br /> producing substantially sulfur-free product gases. </p> <p>As another added feature of the present invention, a portion of the liquid<br /> hydrocarbon feed, prior to its introduction to the molten metal feed zone,<br /> may be used as a scrubbing medium to remove dust from the hydrogen-rich and<br /> carbon monoxide-rich gases (6524AUS). The portion of the hydrocarbon feed<br /> containing the removed dust is then joined with the remainder of the<br /> hydrocarbon feed and introduced to the feed zone, thereby providing a<br /> direct and inexpensive means of recovering and recycling the dust back to<br /> the molten metal bath. </p> <p>As still another added feature of the present invention, the liquid<br /> hydrocarbon feed containing removed dust may be passed through a magnetic<br /> separation device to preferentially separate out a portion of the low-iron<br /> dust from the hydrocarbon feed before it is fed to the molten metal feed<br /> zone. In this manner, a portion of the non-iron slag compounds which can<br /> build up in the molten metal bath over time may be continuously removed<br /> from the system. </p> <p>***************snipped*************</p>

<p>Peter wrote/found:<br /> Why not just make gaoline and diesel??</p> <p> United States Patent: 5,763,716 </p> <p> Benham , et al. June 9, 1998 </p> <p> Process for the production of hydrocarbons </p> <p> 10. Abstract<br /> A process of converting a feed of hydrocarbon-containing gases into liquid hydrocarbon products including a first reaction of converting the feed into one to 2.5 parts of hydrogen to one part carbon monoxide in the presence<br /> of carbon dioxide and then secondly reacting the hydrogen and carbon monoxide in a Fischer-Tropsch synthesis reactor using a promoted iron oxide catalyst slurry to form liquid hydrocarbon products, wherein the carbon dioxide from the<br /> first and second reactions is separated from the product streams and at least a portion of the separated carbon dioxide is recycled into the first reaction feed<br /> and the hydrocarbon products are separated by distillation and a normally gaseous portion of the separated products are further reacted in another Fischer-Tropsch synthesis reactor to produce additional liquid hydrocarbon product. </p> <p>Jumping to:</p> <p>There have only been a few instances wherein the Fischer-Tropsch reaction has been incorporated into a complete system, starting with a solid or gaseous feedstock. Germany placed several plants in operation during the 1930's<br /> and 1940's using coal as the feed stock, referenced in Twenty-Five Years of Synthesis of Gasoline by Catalytic Conversion of Carbon Monoxide and Hydrogen, Helmut Pichler, Advances in Catalysis, 1952, Vol. 4, pp. 272-341. In<br /> addition to the foregoing, South Africa has been using Fischer-Tropsch technology based upon this German work for the past 35 years to produce gasoline and a variety of ther products from coal, referenced in Sasol Upgrades Synfuels with Refining Technology, J. S. Swart, G. J. Czajkowski, and R. E. Conser, Oil &amp; Gas Journal, Aug. 31, 1991, TECHNOLOGY. There was also a Fischer-Tropsch plant<br /> built in the late 1940's to convert natural gas to gasoline and diesel fuel described in Carthage Hydrocol Project by G. Weber, Oil Gas Journal, 1949, Vol. 47, No. 47, pp. 248-250. These early efforts confirmed that commercial<br /> application of the Fischer-Tropsch process for the synthesis of hydrocarbons from a hydrocarbon-containing feed stock gas requires solving, in an economical manner,<br /> a set of complex problems associated with the complete system. For example, initially, it is important for the hydrocarbon-containing feed stock to be converted into a mixture consisting essentially of hydrogen and carbon monoxide before introduction of the mixture into the Fischer-Tropsch reactor. </p> <p>Economic operation of specific sizes of Fischer-Tropsch reactors, generally requires the ratio of hydrogen to carbon monoxide to be within well established ranges. The<br /> Hydrocol plant, referenced hereinbefore, used partial oxidation of natural gas to achieve a hydrogen to carbon monoxide ratio of about 2.0. </p> <p>An alternative approach to partial oxidation uses steam reforming for converting light hydrocarbon-containing gases into a mixture of hydrogen and carbon monoxide. In this latter case, steam and carbon dioxide, methane and water are<br /> employed as feed stocks and carbon dioxide can be recycled from the output of the reformer back to its inlet for the purpose of reducing the resultant hydrogen to carbon noxide ratio. </p> <p>There are therefore, two primary methods for producing synthesis gas from methane: steam reforming and partial oxidation. </p> <p>Steam reforming of methane takes place according to the following reaction: </p> <p>H.sub.2 O+CH.sub.4 .apprxeq.3H.sub.2 +CO (1) </p> <p>Since both steam and carbon monoxide are present, the water gas shift reaction also takes place: </p> <p> 142. H.sub.2 O+CO.apprxeq.H.sub.2 +CO.sub.2 ( 2) </p> <p>Both of these reactions are reversible, i.e., the extent to which they proceed as written depends upon the conditions of temperature and pressure employed. High temperature and low pressure favor the production of synthesis gas. </p> <p>Partial oxidation reactions utilize a limited amount of oxygen with hydrocarbon-containing gases, such as methane, to produce hydrogen and carbon monoxide, as shown in equation (3), instead of water and carbon dioxide in the<br /> case of complete oxidation. </p> <p>1/2 O.sub.2 +CH.sub.4 .fwdarw.2H.sub.2 +CO (3) </p> <p>In actuality, this reaction is difficult to carry out as written. There will always be some production of water and carbon dioxide; therefore the water gas shift reaction (2) will also take place. As in the steam reforming case,<br /> relatively high temperatures and relatively low pressures favor production of synthesis gas. </p> <p>The primary advantage of partial oxidation over steam reforming is that once the reactants have been preheated, the reaction is self-sustaining without the need for the addition of heat. </p> <p>Another advantage of partial oxidation is the lower ratios of hydrogen to carbon monoxide normally produced in the synthesis gas which ratios better match the desired ratio for use in the Fischer-Tropsch synthesis of hydrocarbon<br /> liquids in the overall process. </p> <p>A still further advantage of partial oxidation resides in the elimination of a need for the removal of carbon dioxide and/or hydrogen from the synthesis gas before being fed to the synthesis reactors. </p> <p>While adjustment of the hydrogen to carbon monoxide ratio can be achieved by removal of excess hydrogen using a membrane separator, for example. This approach requires additional capital equipment and can result in lower oil or<br /> liquid hyrdrocarbon yields due to a loss of hydrogen to the process. </p> <p>In order for the overall process considerations to be used in a manner which can produce economical results whether employing either steam reforming or partial oxidation of a feed stock, the Fischer-Tropsch reactor must typically<br /> be able to convert at least 90% of the incoming carbon monoxide. If a 90% conversion efficiency is to be achieved in single pass operation and hydrogen is not removed before introduction of the gas stream into the reactor, the<br /> build up of unreacted hydrogen due to the excess of hydrogen will necessitate a larger reaction vessel to maintain a sufficiently long residence time in the<br /> reaction vessel.</p> <p>Recycle of unreacted hydrogen and carbon monoxide from the<br /> outlet of the Fischer-Tropsch reactor back to its inlet is commonly employed to achieve the required conversion. However, when an excess of hydrogen is employed, an even<br /> greater excess of unreacted hydrogen will build up under such a recycle operation. This condition, in turn, can necessitate an even larger reaction vessel or alternatively the hydrogen removal described must be employed. </p> <p>Major drawbacks to the commercialization of many of the prior processes were the high cost of product specific catalysts, and when an inexpensive catalyst was utilized an unacceptable overall process conversion efficiency of the<br /> carbon input into the hydrocarbon products produced. </p> <p>The two catalyst types attracting the most serious attention for the Fischer-Tropsch reaction are either cobalt based or iron-based catalysts. In practice, a cobalt-based catalyst will favor the following reaction: </p> <p> CO+2H.sub.2 .fwdarw.(--CH.sub.2 --)+H.sub.2 O (4) </p> <p>While an iron catalyst will favor the following overall reaction (due to its high water gas shift activity): </p> <p> 2CO+H.sub.2 .fwdarw.(--CH.sub.2 --)+CO.sub.2 ( 5) </p> <p>Theoretically, cobalt-based catalysts can produce higher conversion yields than iron-based catalysts since cobalt can approach 100% carbon conversion efficiency, whereas iron tends toward 50% carbon conversion efficiency during<br /> the Fischer-Tropsch synthesis reaction since the reaction (5) favors the production of carbon in the form of CO.sub.2. The major drawbacks encountered are, first, that cobalt-based catalysts are very expensive compared to<br /> iron-based catalysts and, further, if the Fischer-Tropsch technology was embraced worldwide on a large scale, the higher demand for relatively scarce cobalt might drive the cost even higher. </p> <p>The use of cobalt-based catalysts has typically included recycle of tail effluent back to the inlet of the Fischer-Tropsch reactor to achieve 90% conversion primarily because cobalt favors formation of water. Too much water has been considered to be an inhibitor of either catalytic reaction<br /> scheme. Thus, as the reaction proceeds in the presence of water, not only is the concentration of reactants less, but the concentration of inhibiting water vapor is greater. In practice, generally 70% carbon monoxide conversion is the maximum attainable in single-pass operation using a cobalt-based catalyst.</p> <p>Iron-based catalysts, which favor carbon dioxide formation permit up to 90% of the theoretical conversion of carbon monoxide per pass without great difficulty, and without the formation of additional water, thereby eliminating the<br /> necessity for effluent recycle back to the inlet of the Fischer-Tropsch reactor. </p> <p>It has generally been considered undesirable to form CO.sub.2 in the Fischer-Tropsch synthesis reaction as happens using iron-based catalysts and therefore many process schemes use cobalt-based catalysts including<br /> the recycle of some of the reactor effluent directly back into the Fischer-Tropsch reactor.</p> <p>In summary, therefore, iron-based catalysts, while efficient in converting carbon monoxide into the products shown in equation (5), have previously been limited in overall carbon conversion efficiency since their use<br /> favors the production of carbon dioxide, and therefore, they were not as efficient in overall carbon conversion efficiency to hydrocarbon products compared to the<br /> process schemes utilizing cobalt based catalysts. </p> <p>The Fischer-Tropsch synthesis has commercially therefore been used incombination with an up-stream steam reforming reactor which must then be followed by CO.sub.2 removal from the carbon monoxide and hydrogen reaction products before the CO and H.sub.2 synthesis gas produced by the<br /> steam reforming reaction are subjected to a Fischer-Tropsch reaction using cobalt-based catalysts. </p> <p>In selecting a suitable catalyst for use in a system which favors reaction (5), several considerations are important. In the Fischer-Tropsch synthesis using appropriately designed equipment, the hydrogen to carbon monoxide feed ratio to the Fischer-Tropsch reactor will optimally be in the range of from 0.6 to 2.5 parts of hydrogen for every part of carbon monoxide. This is necessary in order to obtain reasonably acceptable percent conversion of carbon monoxide into hydrocarbon per pass through the Fischer-Tropsch reactor without the undesirable formation of carbon in the catalyst bed. </p> <p>In order to provide the H.sub.2 /CO ratio in the range of optimum ratios described hereinbefore for the catalyst selected, it is necessary and typical that an additional stage of hydrogen removal, by a membrane or the like, is<br /> inserted into the product stream between the steam reformer and the Fischer-Tropsch reactor. </p> <p>The present invention overcomes the foregoing difficulties, and provides a novel, unobvious and effective economically viable natural gas to oil conversion process using steam reforming or partial oxidation and a Fischer-Tropsch<br /> synthesis using a promoted iron-based unsupported catalyst in a slurry reactor. </p> <p>The present invention includes a solution to the problems of reducing the formation of excess hydrogen from the reformer or partial oxidation unit and increasing the overall carbon conversion efficiency for the entire<br /> carbon input to the system when using specifically prepared promoted iron catalysts. As will be shown hereinafter, the carbon dioxide produced by such iron catalysts, contributes to the low carbon conversion efficiencies previously discussed, and can be used to solve both the excess hydrogen and low overall carbon conversion<br /> efficiency problems. </p> <p>Again jumping to:</p> <p>The hydrogen and carbon monoxide-containing gas stream 12 is then introduced into a Fischer-Tropsch reactor which employs a catalyst slurry using an iron-based catalyst and preferably a precipitated iron catalyst and most<br /> preferably a precipitated iron catalyst that is promoted with predetermined amounts of potassium and copper depending on the preselected probability of linear condensation polymerization, i.e. chain growth, and product<br /> molecular weight distribution sought. </p> <p>There are three fundamental aspects to producing a catalyst for a particular application: (1) composition, (2) method of preparation, and (3) procedure for its activation. </p> <p>The preferred catalyst herein is an unsupported recipitated iron catalyst promoted with copper and potassium. The catalyst is made using elemental iron 473. and copper as starting materials. </p> <p>The first step in the cataylst preparation process is dissolution of the starting metals in nitric acid to form a mixture of ferrous nitrate, ferric nitrate and cupric nitrate in appropriate proportions. The ratio of water to<br /> acid is an important parameter and should be adjusted to give a weight ratio of about 6:1. The dissolution of the metals in nitric acid either by the addition of the metal to the acid or the acid to the metal produces an<br /> evolution of nitrogen oxides, principally nitric oxide and nitrogen dioxide.</p> <p>Nitric oxide has limited solubility in the acid, but can be readily oxidized to nitrogen dioxide by contact with air or oxygen. Nitrogen dioxide dissolves in water producing<br /> nitric acid and nitric oxide, respectively. Therefore, in order to reduce nitrogen oxide emissions from the reaction vessel and, at the same time, to reduce the consumption of nitric acid needed for dissolution of the metals,<br /> oxygen is bubbled through the solution while the metals are being dissolved. The small amount of nitrogen dioxide which escapes from the vessel is scrubbed using a potassium hydroxide or other basic solution such as of ammonium<br /> hydroxide. The mixture is stirred until the metals are totally dissolved. The temperature of the solution increases as the metals dissolve, but is preferably<br /> controlled to a maximum temperature of about 150.degree. C. </p> <p>The next step in the catalyst process is precipitation of a catalyst precursor from the nitrate solution using ammonium hydroxide. Ammonium hydroxide is prepared by dissolving anhydrous ammonia in water. Ammonium hydroxide at ambient<br /> temperature is added to the hot nitrate solution until the pH of the solution reaches 7.4. At this point, all of the metals have precipitated out as oxides. </p> <p>The mixture is cooled to 80.degree. F. and the final pH is adjusted to 7.2. After precipitation, the catalyst recursor must be washed free of ammonium nitrate using high quality water which is free of chlorine. The slurry is first<br /> pumped from the precipitation vessel into a holding tank located upstream of a vacuum drum filter. </p> <p>The catalyst precursor is allowed to settle in<br /> the holding tank, and a clear layer of concentrated ammonium nitrate solution forms above the solids. This layer is drawn off, such as by decantation or by centrifugation before the slurry is washed and filtered. A vacuum drum filter fitted with water spray bars is used for washing the catalyst precursor and concentrating the<br /> slurry.</p> <p>The electrical conductivity of the filtrate is monitored to<br /> ensure complete removal of ammonium nitrate from the slurry. </p> <p>After the catalyst precursor has been washed, the last ingredient of the catalyst, potassium carbonate, is added in an amount appropriate for the quantity of iron contained in the batch. The potassium carbonate is dissolved in a small amount of water and this solution is mixed thoroughly into the slurry to distribute the potassium uniformly. At this point, catalyst present in the slurry should preferably be between about 8 to about 12% by weight. </p> <p>Heat, such as from a spray dryer, is used to remove most of the water from the catalyst and at the same time to produce roughly spherical catalyst particles having diameters in the range of about 1 to about 5 up to about 40 to about 50<br /> microns. </p> <p>The last step in the process is annealing by heating the catalyst in air to about 600.degree. F. to remove residual moisture and to stabilize the catalyst. Chemically, the annealing step converts the hydrous iron oxide<br /> Goethit Fe.sub.2 O.sub.3 H.sub.2 O, to Hematite, Fe.sub.2 O.sub.3. This step is carried out in a fluidized bed which can be electrically heated. The annealed catalyst is then<br /> ready for induction or activation and use. </p> <p>Determining the "best" activating procedure for a catalyst is difficult at best even if it is known what changes in the catalyst are needed to give the desired activity, selectivity and stability. Many different activating<br /> procedures for making promoted Fischer Tropsch iron catalysts have been described in the literature. For example, one of the most definitive studies on<br /> activating Fischer Tropsch iron catalysts for use in fixed-bed reactors was published by Pichler and Merkel. (United States Department of Interior Bureau of Mines, Technical Paper 718, By H. Pickler and H. Merkel, Translated by Ruth<br /> Brinkley with Preface and Foreword by L. J. E. Hofer, United States Government Printing Office, Washington, D.C., 1949, Chemical and Thermomagnetic Studies on Iron Catalysts For Synthesis of Hydrocarbons). In this study, high activity of the catalyst was correlated with the presence of iron carbides after the activation<br /> procedure. The most effective procedure used carbon monoxide at 325.degree. C. at 0.1 atm. pressure. The study also showed how the presence of copper and potassium in the catalyst affected activation of the catalyst. </p> <p>The following equations show the stoichiometry for some of the reactions which can take place during activation: </p> <p>Production of Cementite from Hematite using hydrogen-rich synthesis gas: </p> <p>3Fe3.sub.2 O.sub.3 +11H.sub.2 +2CO.fwdarw.2Fe.sub.3 C+11H.sub.2 O(6) </p> <p>Production of Cementite from Hematite using carbon monoxide alone: </p> <p>3Fe.sub.2 O.sub.3 +13CO.fwdarw.2Fe.sub.3 C+11CO.sub.2 (7) </p> <p>In the presence of an iron-based catalyst, the following reactions take place: </p> <p>2nH.sub.2 +nCO.fwdarw.C.sub.n H.sub.2n --+nH.sub.2 O (olefin)(8) </p> <p>and ##EQU1## </p> <p>Water gas shift reaction: </p> <p>H.sub.2 O+CO.apprxeq.H.sub.2 +CO.sub.2 (10) </p>

<p>Peter wrote/found:<br /> OK -- found the more exact reference:</p> <p><a href="http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO2&amp;Sect2=HITOFF&amp;u=/netahtm">http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO2&amp;Sect2=HITOFF&amp;u=/netahtm</a><br /> l/search-adv.htm&amp;r=3&amp;f=G&amp;l=50&amp;d=PALL&amp;p=1&amp;S1=4,496,369&amp;OS=4,496,369&amp;RS=4,496,<br /> 369</p> <p>United States Patent 5,537,940<br /> Nagel , et al. July 23, 1996 </p> <p>--------------------------------------------------------------------------</p> <p>Method for treating organic waste </p> <p>Abstract<br /> Organic waste is treated in a molten metal bath to sequentially form<br /> enriched hydrogen gas and carbon oxide gas streams. The method includes<br /> introducing organic waste to a molten metal bath in the absence of a<br /> separate oxidizing agent and under conditions that will decompose the<br /> organic waste. As a consequence of this decomposition, an enriched hydrogen<br /> gas stream is generated and the molten metal bath becomes carbonized.<br /> Thereafter, an oxidizing agent is added to the carbonized molten metal bath<br /> to oxidize the carbon contained in the carbonized molten metal bath.<br /> Reaction of the oxidizing agent with the carbon causes formation of a<br /> carbon oxide that escapes from the bath as an enriched carbon oxide gas<br /> stream, thereby decarbonizing the molten metal bath. </p> <p>BACKGROUND OF THE INVENTION </p> <p>Disposal of organic wastes in landfills and by incineration has become an<br /> increasingly difficult problem because of diminishing availability of<br /> disposal space, strengthened governmental regulations, and the growing<br /> public awareness of the impact of hazardous substance contamination upon<br /> the environment. Release of hazardous organic wastes to the environment can<br /> contaminate air and water supplies thereby diminishing the quality of life<br /> in the affected populations. </p> <p>To minimize the environmental effects of the disposal of organic wastes,<br /> methods must be developed to convert these wastes into benign, and<br /> preferably, useful substances. In response to this need, there has been a<br /> substantial investment in the development of alternate methods for suitably<br /> treating hazardous organic wastes. One of the most promising new methods is<br /> described in U.S. Pat. Nos. 4,574,714 and 4,602,574, issued to Bach and<br /> Nagel. The Bach/Nagel method for destroying organic material, including<br /> toxic wastes, involves decomposition of the organic material to its atomic<br /> constituents in a molten metal and reformation of these atomic constituents<br /> into environmentally acceptable products, including hydrogen, carbon<br /> monoxide and/or carbon dioxide gases. </p> <p>SUMMARY OF THE INVENTION </p> <p>The present invention relates to a method for treating organic waste in<br /> molten metal contained in a vessel to sequentially form enriched hydrogen<br /> gas and carbon oxide gas streams. </p> <p>In one embodiment, an organic waste containing hydrogen and carbon is<br /> introduced into molten metal, without the addition of a separate oxidizing<br /> agent and under conditions sufficient to decompose the organic waste and to<br /> generate an enriched hydrogen gas stream and to carbonize the molten metal.<br /> The enriched hydrogen gas stream is substantially removed from the vessel.<br /> Thereafter, a separate oxidizing agent is added into the carbonized molten<br /> metal to oxidize carbon contained in the carbonized molten metal to form an<br /> enriched carbon oxide gas stream. The enriched carbon oxide gas stream is<br /> substantially removed from the vessel. </p> <p>In another embodiment of the invention employed to increase the amount of<br /> carbon dioxide to carbon monoxide in the enriched carbon oxide gas stream,<br /> the organic waste is introduced into molten metal contained in a vessel<br /> which comprises two immiscible metals wherein the first immiscible metal<br /> has a free energy of oxidation, at the operating conditions, greater than<br /> that for oxidation of carbon to carbon monoxide and the second immiscible<br /> metal has a free energy of oxidation, at the operating conditions, greater<br /> than that for oxidation of carbon monoxide to carbon dioxide, without the<br /> addition of a separate oxidizing agent and under conditions sufficient to<br /> decompose the organic waste and to generate an enriched hydrogen gas stream<br /> and to carbonize at least one of the two immiscible metals. The enriched<br /> hydrogen gas stream is substantially removed from the vessel. Thereafter, a<br /> separate oxidizing agent is added into the carbonized molten metal to<br /> oxidize carbon contained in the carbonized molten metal to generate an<br /> enriched carbon monoxide and carbon dioxide gas stream having a<br /> significantly increased ratio of carbon dioxide/carbon monoxide compared to<br /> that produced in molten iron under the same conditions and decarbonizing<br /> the molten metal. The enriched carbon oxide gas stream is substantially<br /> removed from the vessel. </p> <p>This invention has the advantage of treating organic waste to form an<br /> enriched stream of hydrogen gas and a separate enriched stream of carbon<br /> oxide gas, such as carbon monoxide or carbon dioxide or both. Enriched<br /> hydrogen and/or carbon oxide gas streams are often desired. For example, an<br /> enriched stream of hydrogen gas is particularly useful in the synthesis of<br /> ammonia or oxoalcohol and in hydrogenation or desulfurization processes.<br /> Hydrogen is also an excellent "clean" or "greenhouse gas free" fuel. </p>

<p>Peter wrote:<br /> I also worked for a while in a cast iron foundry and remember the H2<br /> evolved when stirring molten cast iron in the pot with a hard wood stick.</p> <p>It was a very old fashioned operation.</p> <p>But I simply loved pouring molten cast iron into a mold I had made up and<br /> breaking it out later -- solid!!</p> <p>by the way -- all those articles are archived under a folder titles:</p> <p>Molten liquid metal bath gasifiers</p> <p>Peter </p>