A family of new crystalline molecular sieves designated SSZ-91 is disclosed, as are methods for making SSZ-91 and uses for SSZ-91. Molecular sieve SSZ-91 is structurally similar to sieves falling within the ZSM-48 family of molecular sieves, and is characterized as: (1) having a low degree of faulting, (2) a low aspect ratio that inhibits hydrocracking as compared to conventional ZSM-48 materials having an aspect ratio of greater than 8, and (3) is substantially phase pure.

Processes for converting methane and/or other hydrocarbons to synthesis gas (i.e., a gaseous mixture comprising H.sub.2 and CO) are disclosed, in which at least a portion of the hydrocarbon(s) is reacted with CO.sub.2. At least a second portion of the methane may be reacted with H.sub.2O (steam), thereby improving overall thermodynamics of the process, in terms of reducing endothermicity (ΔH) and the required energy input, compared to “pure” dry reforming in which no H.sub.2O is present. Such dry reforming (reaction with CO.sub.2 only) or CO.sub.2-steam reforming (reaction with both CO.sub.2 and steam) processes are advantageously integrated with Fischer-Tropsch synthesis to yield liquid hydrocarbon fuels. Further integration may involve the use of a downstream finishing stage involving hydroisomerization to remove FT wax. Yet other integration options involve the use of combined CO.sub.2-steam reforming and FT synthesis stages (optionally with finishing) for producing liquid fuels from gas streams generated in a number of possible processes, including the hydropyrolysis of biomass.

Processes for converting methane and/or other hydrocarbons to synthesis gas (i.e., a gaseous mixture comprising H.sub.2 and CO) are disclosed, in which at least a portion of the hydrocarbon(s) is reacted with CO.sub.2. At least a second portion of the methane may be reacted with H.sub.2O (steam), thereby improving overall thermodynamics of the process, in terms of reducing endothermicity (ΔH) and the required energy input, compared to “pure” dry reforming in which no H.sub.2O is present. Such dry reforming (reaction with CO.sub.2 only) or CO.sub.2-steam reforming (reaction with both CO.sub.2 and steam) processes are advantageously integrated with Fischer-Tropsch synthesis to yield liquid hydrocarbon fuels. Further integration may involve the use of a downstream finishing stage involving hydroisomerization to remove FT wax. Yet other integration options involve the use of combined CO.sub.2-steam reforming and FT synthesis stages (optionally with finishing) for producing liquid fuels from gas streams generated in a number of possible processes, including the hydropyrolysis of biomass.

Improved systems and methods for producing propylene from olefins including isobutylene is disclosed. The improvements combine streams containing co-produced 1-butene, 2-butene, butadiene, and heavy olefins (C5+) exiting both a metathesis reactor and a skeletal isomerization reactor in a gasoline fractionation tower to remove the heavy olefins. The C4-containing distillate from the gasoline fractionation tower is then fed to a hydroisomerization unit to form mono-olefins and 2-butene. The resulting 2-butene rich stream can then be utilized in metathesis reactions to increase the production of propylene while increasing the lifetime of the metathesis catalyst.

Improved systems and methods for producing propylene from olefins including isobutylene is disclosed. The improvements combine streams containing co-produced 1-butene, 2-butene, butadiene, and heavy olefins (C5+) exiting both a metathesis reactor and a skeletal isomerization reactor in a gasoline fractionation tower to remove the heavy olefins. The C4-containing distillate from the gasoline fractionation tower is then fed to a hydroisomerization unit to form mono-olefins and 2-butene. The resulting 2-butene rich stream can then be utilized in metathesis reactions to increase the production of propylene while increasing the lifetime of the metathesis catalyst.

Improved systems and methods for producing propylene from olefins including isobutylene is disclosed. The improvements combine streams containing co-produced 1-butene, 2-butene, butadiene, and heavy olefins (C5+) exiting both a metathesis reactor and a skeletal isomerization reactor in a gasoline fractionation tower to remove the heavy olefins. The C4-containing distillate from the gasoline fractionation tower is then fed to a hydroisomerization unit to form mono-olefins and 2-butene. The resulting 2-butene rich stream can then be utilized in metathesis reactions to increase the production of propylene while increasing the lifetime of the metathesis catalyst.

A method for converting cedarwood oil into high density fuels including, hydrogenating cedarwood oil in the presence of at least one hydrogenation catalyst to generate hydrogenated cedarwood oil, removing the hydrogenation catalyst from the hydrogenated cedarwood oil, purifying the hydrogenated cedarwood oil to produce a first high density fuel, isomerizing the first high density fuel in the presence of at least one acid catalyst catalyst to generate a hydrocarbon mixture including adamantanes, and distilling the adamantane mixture to produce a second alkyl-adamantane high density fuel.

A method for converting cedarwood oil into high density fuels including, hydrogenating cedarwood oil in the presence of at least one hydrogenation catalyst to generate hydrogenated cedarwood oil, removing the hydrogenation catalyst from the hydrogenated cedarwood oil, purifying the hydrogenated cedarwood oil to produce a first high density fuel, isomerizing the first high density fuel in the presence of at least one acid catalyst catalyst to generate a hydrocarbon mixture including adamantanes, and distilling the adamantane mixture to produce a second alkyl-adamantane high density fuel.

Isobutanol may be converted into predominantly C.sub.12+ olefin oligomers under specified conditions. Such methods may comprise: contacting a feed comprising isobutanol with a zeolite solid acid catalyst having a MWW framework under conditions effective to convert the isobutanol into a product comprising C.sub.4n olefin oligomers, wherein n is an integer having a value of two or greater and about 80 wt. % or greater of the C.sub.4n olefin oligomers are larger than C.sub.8.

Isobutanol may be converted into predominantly C.sub.12+ olefin oligomers under specified conditions. Such methods may comprise: contacting a feed comprising isobutanol with a zeolite solid acid catalyst having a MWW framework under conditions effective to convert the isobutanol into a product comprising C.sub.4n olefin oligomers, wherein n is an integer having a value of two or greater and about 80 wt. % or greater of the C.sub.4n olefin oligomers are larger than C.sub.8.