Exxon Research and Engineering Company

Exxonmobil Research and Engineering Company

Geoffrey R Say

LeRoy R Clavenna

James H Taylor, Jr

Rocco A Fiato

Stephen M Davis

James P Glass, Jr

Richard P O'Connor

James R Hays, Sr

Jagannathan N Iyengar

William C Baird, Jr

Robert J Wittenbrink

Kenneth S Wheelock

Louis F Burns

Robert Basil Fedich

Gregg Johnston Howsmon

Dennis G Alexion

Duane A Goetsch

Mark Leland Tiller

John C Wilbur

Gerald A Wilcox

Guido Sartori

Charles H Mauldin

Paul E Eberly

W S Ho

Jose M Vargas

Paul W Kamienski

Charles A Euker, Jr

David C Long

Fred J Heinzelmann

Nikos J Maris

Robert H Shabaker

George R Chludzinski

Barbara A Hacker

Noah S Rothblatt

Norman J Eger

Lawrence J Delaune

Sour natural gas is processed to remove the sulfur compounds and recover C /C hydrocarbons by scrubbing the gas with an amine solution to remove most of the sulfur, followed cooling the gas to remove C /C hydrocarbons and more sulfur compounds as liquid condensate to produce a gas having less than 20 vppm of total sulfur. The condensate is sent to a fractionator to recover the C /C hydrocarbons. The sulfur and hydrocarbon reduced gas is contacted first with zinc oxide and then nickel, to produce a gas having less than 10 vppb of total sulfur which is passed into a synthesis gas generating unit to form a very low sulfur synthesis gas comprising a mixture of H and CO. This synthesis gas is useful for hydrocarbon synthesis with increased life of the hydrocarbon synthesis catalyst and greater hydrocarbon production from the hydrocarbon synthesis reactor. Contacting the synthesis gas with zinc oxide further reduces the sulfur content to below 3 vppb.

Production of low sulfur syngas from natural gas with C4&plus;/C5&plus; hydrocarbon recovery

A hydrocarbon wax product from a HCS slurry comprising liquid synthesis product and catalyst particles is purified by circulating the slurry from a synthesis zone with a first temperature through a treatment zone with a second temperature in which a hydrogen-containing treatment gas contacts the slurry. The gas treatment removes impurities from the hydrocarbon wax product and also removes catalyst de-activating species which may be present in the slurry. Purified wax product is separated and removed from the treated slurry via wax withdrawal means. This avoids or minimizes the need for further treating the wax product. Remaining treated slurry may be returned to the synthesis zone.

Temperature controlled in situ wax purification

A hydrocarbon synthesis (HCS) process wherein a Fischer-Tropsch reactor is operated to maximize the selectivity to 371&deg; C.&plus; boiling fraction while minimizing the production of less valuable products such as light gases (C -C ), naphtha and diesel fractions. Inventive modes of operation to offset the effects of catalyst deactivation and maximize selectivity to 371&deg; C.&plus; boiling fraction are utilized including (a) reducing gas inlet velocity to maintain an optimal CO conversion level, (b) introducing additional active catalyst until a maximum loading is reached, and (c) increasing reactor temperature until productivity reaches a predetermined cut-off level.

Process for maximizing 371&deg; C.&plus; production in fischer-tropsch process

Sour natural gas is processed to remove the sulfur compounds and recover C,/C,hydrocarbons by scrubbing the gas with an amine solution to remove most of the sulfur, followed cooling the gas to remove C,/C,hydrocarbons and more sulfur compounds as liquid condensate to produce a gas having less than 20 vppm of total sulfur. The condensate is sent to a fractionator to recover the C,C,hydrocarbons. The sulfur and hydrocarbon reduced gas is contacted first with zinc oxide and then nickel, to produce a gas having less than 10 vppb of total sulfur which is passed into a synthesis gas generating unit to form a very low sulfur synthesis gas comprising a mixture of H,and CO. This synthesis gas is useful for hydrocarbon synthesis with increased life of the hydrocarbon synthesis catalyst and greater hydrocarbon production from the hydrocarbon synthesis reactor. Contacting the synthesis gas with zinc oxide further reduces the sulfur content to below 3 vppb.

Production of low sulfer syngas from natural gas with C4&plus;/C5&plus; hydrocarbon recovery

Very low sulfur content hydrocarbon gas is achieved by sequentially contacting the gas first with zinc oxide and then with nickel metal. This has reduced the total sulfur content of natural gas feed for a fluid bed syngas generator to less than 0.1 ppm and has resulted in greater syngas productivity. A zinc oxide guard bed downstream of the syngas generator reduces the total sulfur content of the syngas to less than 10 vppb and preferably less than 5 vppb. This very low sulfur content syngas is used for sulfur sensitive processes, such as hydrocarbon synthesis. The process is especially useful for natural gas which contains H.sub.2 S, COS, mercaptans and other sulfur bearing compounds.

Very low sulfur gas feeds for sulfur sensitive syngas and hydrocarbon

Process, and apparatus, for the production of hydrogen and carbon monoxide in a reactor, preferably one containing a bed of a particulate solids catalyst, or catalyst and solids diluent, by contacting and reacting within the reaction zone a low molecular weight hydrocarbon feed, steam and oxygen, or a low molecular weight hydrocarbon feed and oxygen, at high temperature. An oxygen stream preheated to high temperature is fed via a nozzle inlet, or inlets, into the reactor, while the hydrocarbon and steam, or hydrocarbon, is fed via a different nozzle inlet, or inlets, into the reactor. Preferred oxygen nozzle designs are constituted of nickel-chromium-iron alloys, especially Inconel 600, and Inconel alloys of the 600 series generally. The oxygen nozzle is comprised of a tubular body with inlet, and outlets of special design, which renders the nozzle especially useful in the intensely hot oxygen environment.

Process, and apparatus, for the injection of preheated oxygen into a

High surface purity heat transfer solids are formed, suitably by washing and treating particulate refractory inorganic solids, notably alumina, which contains as impurities up to about 0.5 wt. % silicon and/or up to about 500 wppm boron, with an acid, or dilute acid solution sufficient to reduce the concentration of silicon and boron in the outer peripheral surface layer of the particles, e.g., as measured inwardly toward the center of a particle to a depth of about 50 .ANG. using X-ray photoelectron spectroscopy, to no greater than about 5 atom percent silicon and boron, preferably about 2 atom percent silicon and boron, based on the total number of cations within said outer peripheral surface layer, thereby reducing the tendency of said particles to sinter and agglomerate in the conversion of said hydrocarbon to hydrogen and carbon monoxide in a fluidized bed synthesis gas operation vis-a-vis particles otherwise similar except that the particles are not treated with the acid. The tendency of the particles to sinter and agglomerate is further reduced by the additional removal of sodium, iron, calcium, and titanium impurities from the outer peripheral surface layer of the particles. Preferably the latter named impurities, or impurities other than silicon and boron, are reduced to a concentration below about 20 atom %, more preferably to a concentration below about 15 atom %, in the outer surface layer of the particles.

High surface purity heat transfer solids for high temperature fluidized

A particulate, precalcined low silica content zirconia, especially one stabilizer with yttria, is useful as a catalyst support or as a heat transfer solids component for conducting chemical reactions at high temperature, in oxidizing, reducing or hydrothermal conditions, especially in syn gas operations. An admixture of precalcined particulate low silica content zirconia, particularly a low silica content yttria-stabilized zirconia, is employed in a preferred embodiment as a heat transfer solid, in concentrations ranging generally from about 10 wt. % to about 99.9 wt. % with a particulate catalyst notably a nickel-on-alumina catalyst, in concentration ranging generally from about 0. 1 wt. % to about 90 wt. %. Such an admixture provides a particularly useful catalytic contact mass in high temperature oxidizing, reducing and hydrothermal environments, notably in conducting synthesis gas generation operations. This type of bed promotes continuous, highly efficient heat and mass transfer within the reacting gas phase. The presence of the heat transfer solid as a bed component maintains excellent bed fluidization characteristics, suppressing the normal tendency of the catalyst to sinter or agglomerate; tendencies which promote defluidization of the bed. Moreover, the heat transfer particles of the bed are highly attrition resistant, and are chemically compatible with the catalyst particles of the admixture.

Particulate solids for catalyst supports and heat transfer materials

A process for the in situ attrition and break up of an agglomerating, or agglomerated catalyst to maintain and control the fluidization characteristics of a bed wherein low molecular weight hydrocarbons, oxygen and steam are contacted with the bed to produce hydrogen and carbon monoxide via both partial oxidation and steam reforming reactions. The feeds are injected into the reaction zone with mechanical energy input sufficient to balance the intrinsic rate of agglomeration by fracturing and breaking apart in situ the agglomerated catalyst to maintain the fluidization characteristics of the bed throughout the cycle of operation.

High energy level in situ attrition and break up of catalyst to maintain

A process for the production of syn gas (hydrogen and carbon monoxide) by reaction at high temperature between low molecular weight hydrocarbons, steam and oxygen in an impurities-containing refractory lined reaction zone. The lined reaction zone is pretreated with steam, or with steam and a reducing gas, e.g. a mixture of steam and hydrogen to leach out, react with, and transport the impurities, i.e., the reaction products of silica, or silica plus phosphorus or sulfur, or silica plus phosphorus and sulfur, from the reaction zone. Steam alone may be used to leach out, convert the silica to gaseous silicic acid, and remove same from the reaction zone; and then the hydrocarbons, steam and oxygen feeds are introduced into the reaction zone to produce syn gas.

Process for the elimination of silica and other impurities in fluidized

A mixture of hydrocarbons, oxygen and steam is reacted over a fluidized bed, in a first reaction stage, at high temperature to produce, at hydrocarbon conversion levels ranging from about 85 percent to about 92 percent, a reaction product of hydrogen and carbon monoxide in admixture with unreacted hydrocarbons, carbon dioxide and steam. The level of hydrocarbon conversion is further increased by about 0.5 to 5 percent by contacting and endothermically reacting the reaction product mixture over a fixed bed of a high void fraction catalyst in a second reaction stage.

Production of synthesis gas via fluidized bed/fixed bed process

A particulate, precalcined low silica content zirconia, especially one stabilized with yttria, is useful as a catalyst support or as a heat transfer solids component for conducting chemical reactions at high temperature, in oxidizing, reducing or hydrothermal conditions, especially in syn gas operations. An admixture of precalcined particulate low silica content zirconia, particularly a low silica content yttria-stabilized zirconia, is employed in a preferred embodiment as a heat transfer solid, in concentrations ranging generally from about 10 wt. % to about 99.9 wt. %, with a particulate catalyst, notably a nickel-on-alumina catalyst, in concentration ranging generally from about 0.1 wt. % to about 90 wt. %. Such an admixture provides a particularly useful catalytic contact mass in high temperature oxidizing, reducing and hydrothermal environments, notably in conducting synthesis gas generation operations. This type of bed promotes continuous, highly efficient heat and mass transfer within the reacting gas phase. The presence of the heat transfer solid as a bed component maintains excellent bed fluidization characteristics, suppressing the normal tendency of the catalyst to sinter or agglomerate; tendencies which promote defluidization of the bed. Moreover, the heat transfer particles of the bed are highly attrition resistant, and are chemically compatible with the catalyst particles of the admixture.

A structurally modified alumina useful as a catalyst support, or heat transfer solid for fluidized bed synthesis gas processing. A Group IIA metal, or metals, particularly magnesium and barium, is composited with a particulate alumina to provide a catalyst support, or alumina heat transfer solid, having increased resistance to sintering and agglomeration; properties which promote defluidization of the bed in conducting fluidized bed reactions at high temperatures. The particles of preference are represented by formulas (1) and (2), a composite particle being represented by formula (1), as follows:

Structurally modified alumina supports, and heat transfer solids for

Alumina heat transfer solids are admixed with a catalyst, or catalysts, and used in conducting high temperature fluidized bed reactions, particularly in a process for the production of hydrogen and carbon monoxide from a low molecular weight hydrocarbon by contact with a fluidized bed of catalyst and said heat transfer solids at high temperature in the presence of oxygen, or steam, or both oxygen and steam. The particulate heat transfer solids are characterized as having a performance index, PI, greater than 20, preferably greater than 40, as characterized by the formula PI=[(i).times.(ii).times.(iii).times.(iv)].sup.-1 where (i) the peripheral outer surface of the particle contains &lt;5 atom % (Si+B) as impurities, and (ii) &lt;20 atom % Na, Fe, Ca and Ti as impurities, where the bulk concentrations of the (Si+B) is sufficient to migrate into and contaminate the outer surface layer of the particles at process conditions. Moreover the (iii) tapped bulk density of the particles range from about 1.2 g/cc to about 2.5 g/cc, and (iv) the Davison Attrition Index of the particles is no greater than about 12.

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Baton Rouge, LA, United States of America

Geoffrey R Say