CONVERTING BIOMASS TO NAPHTHA

Abstract

The present invention relates to a process and system for forming a hydrocarbon feedstock from a biomass material, and the hydrocarbon feedstock formed therefrom. The present invention also relates to a process and system for forming a bio-derived naphtha fuel from a hydrocarbon feedstock, and the bio-derived naphtha fuel formed therefrom, as well as intermediate treated hydrocarbon feedstocks formed during the process.

Claims

1-89. (canceled)

90. A process for forming a biomass derived hydrocarbon feedstock, suitable for producing bio-naphtha, from a biomass feedstock, comprising the steps of: a. providing a biomass feedstock; b. ensuring the moisture content of the biomass feedstock to 10% or less by weight of the biomass feedstock; c. pyrolyzing the low moisture biomass feedstock at a temperature of at least 950 C. to form a mixture of biochar, hydrocarbon feedstock, non-condensable light gases, and water; and d. separating the hydrocarbon feedstock from the mixture formed in step c.

91. A process according to claim 90, wherein the biomass feedstock comprises cellulose, hemicellulose or lignin-based feedstocks and/or the biomass feedstock is a non-food crop biomass feedstock.

92. A process according to claim 90, wherein the biomass feedstock is in the form of pellets, chips, particulates or a powder, wherein the pellets, chips, particulates or powder have a diameter of from 5 m to 10 cm.

93. A process according to claim 90, wherein initial moisture content of the biomass feedstock is up to 50% by weight of the biomass feedstock, and/or the moisture content of the biomass feedstock in step b. is to 7% or less by weight.

94. A process according to claim 90, wherein the step of ensuring the moisture content of the biomass feedstock is 10% or less by weight of the biomass feedstock comprises reducing the moisture content of the biomass feedstock by use of a vacuum oven, a rotary dryer, a flash dryer or a heat exchanger.

95. A process according to claim 90, wherein the low moisture biomass feedstock is pyrolyzed at temperature of at least 1000 C.

96. A process according to claim 90, wherein heat is provided to the pyrolysis step by convection heating, microwave heating, electrical heating and/or supercritical heating.

97. A process according to claim 90, wherein the low moisture biomass feedstock is pyrolyzed at atmospheric pressure or the low moisture biomass feedstock is pyrolyzed under a pressure of from 850 to 1000 Pa.

98. A process according to claim 90, wherein the low moisture biomass feedstock is pyrolyzed for a period of from 10 seconds to 2 hours.

99. A process according to claim 90, wherein step d. comprises at least partially separating biochar from the hydrocarbon feedstock product; or wherein step d. comprises at least partially separating water from the hydrocarbon feedstock product; or wherein step d. comprises at least partially separating non-condensable light gases from the hydrocarbon feedstock product.

100. A process according to claim 90, further comprising the step of filtering the hydrocarbon feedstock product to at least partially remove contaminants of carbon, graphene, polyaromatic compounds and/or tar, contained therein, the filtration step comprises the use of a membrane filter to remove larger contaminants and/or the filtration step comprises fine filtration to remove smaller contaminants, and wherein the filtration step comprises contacting the hydrocarbon feedstock product with an active carbon compound and/or a crosslinked organic hydrocarbon resin and subsequently separating the hydrocarbon feedstock from the active carbon and/or crosslinked organic hydrocarbon resin compound though filtration, and the active carbon compound and/or crosslinked organic hydrocarbon resin is contacted with the hydrocarbon feedstock product under ambient conditions; and/or wherein the active carbon compound and/or crosslinked organic hydrocarbon resin is contacted with the blended hydrocarbon feedstock product for at least 15 minutes before separation; and/or wherein the step of filtering the hydrocarbon feedstock is performed once or is repeated one or more times.

101. A process according to claim 100, wherein the tar removed from the hydrocarbon feedstock product is recycled and combined with the low moisture biomass feedstock in step c.

102. A process of forming a bio-derived naphtha fuel, comprising the steps of: A. providing a biomass derived hydrocarbon feedstock formed by: i. providing a biomass feedstock; ii. ensuring the moisture content of the biomass feedstock to 10% or less by weight of the biomass feedstock; iii. pyrolyzing the low moisture biomass feedstock at a temperature of at least 950 C. to form a mixture of biochar, hydrocarbon feedstock, non-condensable light gases, and water; and iv. separating the hydrocarbon feedstock from the mixture formed in step Aiii. B. processing the hydrocarbon feedstock to produce a refined bio-oil, wherein the process comprises the steps of: i. at least partially removing sulphur containing components from the hydrocarbon feedstock; ii. hydro-treating the hydrocarbon feedstock; and iii. hydro-isomerising the hydrocarbon feedstock; and C. fractionating the resulting refined bio-oil to obtain a bio-derived naphtha fuel fraction.

103. A process according to claim 102, wherein the sulphur removal step comprises a catalytic hydro-desulphurisation step.

104. A process according to claim 103, wherein the hydro-desulphurisation step is performed at a temperature of from 250 C. to 400 C., and/or wherein the hydro-desulphurisation step is performed at a reaction pressure of from 4 to 6 MPaG.

105. A process according to claim 102, wherein the catalytic hydro-desulphurisation process further comprises the step of degassing the reduced sulphur hydrocarbon feedstock to remove hydrogen disulphide gas by cooling the reduced sulphur hydrocarbon feedstock to a temperature of from 60 to 120 C. and applying a vacuum pressure of less than 6 KPaA, wherein the degassing step removes hydrogen sulphide formed during the catalytic hydro-desulphurisation process, and wherein the hydrogen sulphide is recycled to the hydrocarbon feedstock of step A.

106. (A process according to claim 102, wherein the hydro-treating step is performed at a temperature of from 250 C. to 350 C., and/or wherein the hydro-treating step is performed at a reaction pressure of from 4 MPaG to 6 MPaG, and/or wherein the hydro-treating process further comprises a catalyst as part of a fixed bed or a trickle bed reactor, the catalyst comprises a metal selected from Group IIIB, Group IVB, Group VB, Group VIB, Group VIIB, and Group VIII, of the periodic table.

107. A process according to claim 102, wherein the hydro-isomerisation step is performed at a temperature of from 260 C. to 370 C., and/or wherein the hydro-isomerisation step is performed at a reaction pressure of from 4 MPaG to 6 MPaG, and/or wherein the hydro-isomerisation step further comprises a catalyst as part of a fixed bed or a trickle bed reactor, the catalyst comprises a metal selected from Group VIII of the periodic table.

Description

[0209] The present inventions will now be described with reference to the following non limiting examples, and with reference to the accompanying drawings, in which:

[0210] FIG. 1 illustrates the carbon number distribution of a filtered hydrocarbon feedstock and a reduced sulphur hydrocarbon feedstock formed in accordance with the present invention;

[0211] FIG. 2 illustrates the carbon number distribution of a hydro-treated hydrocarbon feedstock and a refined bio-oil following an isomerisation process formed in accordance with the present invention and

[0212] FIG. 3 illustrates the carbon number distribution of the bio-derived naphtha, jet fuel and diesel formed.

EXAMPLES

[0213] Forming a Bio-Derived Naphtha Fuel from a Hydrocarbon Feedstock

Example 1Filtering a Bio-Derived Hydrocarbon Feedstock

[0214] A bio-derived hydrocarbon feedstock was formed in accordance with the disclosure of the present invention. The hydrocarbon feedstock mainly comprised hydrocarbon compounds but also comprised minor amounts of contaminants such as tar of various sizes, sulphur containing compound, ammonia containing compounds, halogen derivatives, oxygenates and water. The pour point of the feedstock was measured as approximately 17 C., the sulphur content was measured as approximately 67 ppmw and the bromine content was measured as 710.sup.3 mgBr/100 ml.

[0215] The hydrocarbon feedstock was filtered under the following conditions in accordance with the present invention.

[0216] The hydrocarbon feedstock was contacted with an active carbon powder under ambient conditions for at least 10 minutes. The hydrocarbon feedstock was subsequently separated from the active carbon powder through filtration. The process of contacting the hydrocarbon feedstock with an active carbon powder and separating the hydrocarbon feedstock was then repeated.

[0217] The resulting hydrocarbon feedstock showed that the levels of heavy tars and some harmful species, such as nitrogen-containing compounds, had been reduced to an acceptable level.

Example 2Hydro-Desulphurisation of a Filtered Hydrocarbon Feedstock

[0218] The filtered hydrocarbon feedstock was reacted with hydrogen gas at a temperature of from 300 and 350 C., under a reaction pressure of 5 MPaG and wherein the recirculating hydrogen gas to hydrocarbon feedstock ratio was 500 to 1,000 NV/NV. The liquid space velocity of the reaction was maintained at 0.5-2 V/V/hr and the H.sub.2S concentration was maintained at a level of 150 to 250 ppmV. The hydro-desulphurisation reaction was catalysed using a NiMoS catalyst supported on a porous Al.sub.2O.sub.3 substrate.

[0219] Following the hydro-desulphurisation reaction the resulting hydrocarbon feedstock was cooled and first flashed at ambient temperature. The hydrocarbon feedstock was subsequently heated to a temperature of 80 to 100 C. and degassed at a vacuum pressure of less than 5 KPaA to remove trace amounts of H.sub.2S present.

[0220] The sulphur content of the de-sulphurised hydrocarbon was significantly reduced and was below the measurable detection limit (.sup.1 ppmw). The bromine index of the de-sulphurised hydrocarbon feedstock was reduced to about half of the filtered hydrocarbon feedstock, approximately 410.sup.3 mgBr/100 ml. The pour point of the de-sulphurised hydrocarbon feedstock was significantly improved and was reduced to 35 C. No significant cracking occurred as a result of the de-sulphurisation process, as illustrated in FIG. 1.

Example 3Hydro-Treatment of the De-Sulphurised Hydrocarbon Feedstock

[0221] Hydro-treatment of the de-sulphurised hydrocarbon feedstock was performed at a reaction temperature of from 280 to 320 C. and a reaction pressure of approximately 5 MPaG, wherein the recirculated hydrogen gas to de-sulphurised hydrocarbon feedstock ratio was from 500 to 1,000 NV/NV and a liquid space velocity was from 1 to 1.5 V/V/hr. The hydro-treatment was performed in a trickle bed reactor. A Ni catalyst supported on a porous Al.sub.2O.sub.3 substrate was used to catalyse the hydro-treatment step.

[0222] The carbon number distribution of the hydro-treated hydrocarbon feedstock is illustrated in FIG. 2. The bromine index of the hydro-treated hydrocarbon feedstock was, again, significantly reduced compared to the hydro-desulphurised hydrocarbon feedstock to approximately 10 mgBr/100 ml. The pour point of the de-sulphurised hydrocarbon feedstock was maintained at 35 C.

Example 4Hydro-Isomerising the Hydro-Treated Hydrocarbon Feedstock

[0223] The hydro-isomerisation reaction was performed at a reaction temperature of from 310 to 330 C. and a reaction pressure of approximately 5 MPaG, with a recirculating hydrogen gas to hydrocarbon feed ratio of 500 to 1,000 NV/NV and a liquid space velocity of 0.5 to 1 V/V/hr. The reaction was performed on a trickle bed reactor using a supported Pt/Pd catalyst.

[0224] The hydro-isomerised hydrocarbon feedstock was subsequent processed using a hydro-stabilisation treatment. The hydro-stabilisation treatment was performed at a reaction temperature of from 280 to 320 C. and a reaction pressure of approximately 5 MPaG, with a recirculating hydrogen gas to hydrocarbon feed ratio of 500 to 1,000 NV/NV and a liquid space velocity of 1 to 1.5 V/V/hr. The hydro-stabilisation process was performed using a trickle bed reactor and a Ni catalyst supported on a porous Al.sub.2O.sub.3 substrate.

[0225] The carbon number distribution of the refined bio-oil formed is illustrated in FIG. 2. The bromine index of the resulting refined bio-oil was below the measureable detection limit. The pour point of the hydro-stabilised refined bio-oil was further reduced to below 54 C.

[0226] As a result of the refining process, a small amount (<5 wt %) of liquid petroleum gas (LPG) was also formed.

Example 5Fractionating the Refined Bio-Oil to Obtain a Bio-Derived Naphtha Fuel

[0227] The refined bio-oil was first fractionated using a distillation tower under ambient pressure with a cut point of 150 C. Approximately 20 wt % of the refined bio-oil was separated as naphtha from the stream from the top of the distillation tower.

[0228] The first fractionation cut was further fractionated under vacuum with a cut point of 90 C. The stream collected from the top of the distillation tower was a bio-derived light naphtha fuel. The stream collected from the bottom of the distillation tower was a bio-derived heavy naphtha fuel.