Methods and apparatuses for processing renewable feedstocks

Abstract

Embodiments of methods and apparatuses for processing a renewable feedstock are provided herein. In one example, a method comprises dividing a H₂-rich make-up stream into a first H₂-rich portion and a second H₂-rich portion. The second H₂-rich portion has a lower mass flow rate than the first H₂-rich portion. The renewable feedstock is deoxygenated in the presence of the first H₂-rich portion at hydroprocessing conditions effective to form a deoxygenating reaction zone effluent that contains normal paraffins. At least a portion of the deoxygenating reaction zone effluent is isomerized in the presence of the second H₂-rich portion at isomerization conditions effective to form an isomerization reaction zone effluent that contains branched paraffin. The isomerization conditions include a first hydrogen partial pressure of about 4,140 kPa gauge or less.

Description

TECHNICAL FIELD[0001]The technical field relates generally to methods and apparatuses for processing renewable feedstocks, and more particularly relates to methods and apparatuses that deoxygenate renewable feedstocks to form normal paraffins and that isomerize normal paraffins at relatively low hydrogen partial pressure to form branched paraffins for fuel products.BACKGROUND[0002]As the demand for diesel and jet boiling range fuels increase worldwide, there is increasing interest in feedstock sources other than petroleum crude oil. One such source is what has been termed “renewable feedstocks.” Renewable feedstocks are biological feedstocks that include, but are not limited to, plant oils such as corn, jatropha, camelina, rapeseed, canola, and soybean oil; algal oils; and animal fats such as tallow and fish oils. The common feature of these sources is that they are composed of glycerides and free fatty acids (FFA). Both of these classes of compounds contain n-aliphatic hydrocarbon ...

AI Technical Summary

Benefits of technology

[0006]Methods and apparatuses for processing a renewable feedstock are provided herein. In accordance with an exemplary embodiment, a method for processing a renewable feedstock comprises the steps of dividing a H2-rich make-up stream into a first H2-rich portion and a second H2-rich portion. The second H2-rich portion has a lower mass flow rate than the first H2-rich portion. The renewable feedstock is deoxygenated in the presence of the first H2-rich portion at hydroprocessing conditions effective to form a deoxygenating reaction zone effluent that contains normal paraffins. At least a portion of the deoxygenating reaction zone effluent is isomerized in the presence of the second H2-rich portion at isomerization conditions effective to form an isomerization reaction zone effluent that contains branched paraffin. The isomerization conditions include a first hydrogen partial pressure of about 4,140 kPa gauge or less.

[0007]In accordance with another exemplary embodiment, a method for processing a renewable feedstock is provided. The method comprises the steps of separating H2, C3− hydrocarbons, CO, CO2, NH3, H2S, and / or H2O from a deoxygenating reaction zone effluent that contains normal paraffins using a first H2-rich portion of a H2-rich make-up stream to form a liquid normal paraffin-containing stream. A second H2-rich portion of the H2-rich make-up stream is fluidly communicated to an isomerization reaction zone. The second H2-rich portion has a lower mass flow rate than the first H2-rich portion. The liquid normal paraffin-containing stream is contacted with an isomerization catalyst in the presence of the second H2-rich portion in the isomerization reaction zone that is operating at isomerization conditions effective to form an isomerization reaction zone effluent that contains branched paraffin. The isomerization conditions include a first hydrogen partial pressure of about 4,140 kPa gauge or less.

[0008]In accordance with another exemplary embodiment, an apparatus for processing a renewable feedstock is provided. The apparatus comprises a control valve configured to divide a H2-rich make-up stream into a first H2-rich portion and a second H2-rich portion. The second H2-rich portion has a lower mass flow rate than the first H2-rich portion. A deoxygenating reaction zone contains a hydroprocessing catalyst and is configured to deoxygenate the renewable feedstock in the presence of the first H2-rich portion at hydroprocessing conditions effective to form a deoxygenating reaction zone effluent that contains normal paraffins. An isomerization reaction zone contains an isomerization catalyst and is configured to isomerize at least a portion of the deoxygenating reaction zone effluent in the presence of the second H2-rich portion at isomerization conditions effective to form an isomerization reaction zone effluent that contains branched paraffin. The isomerization conditions include a hydrogen partial pressure of about 4,140 kPa gauge or less.

Problems solved by technology

Unfortunately, further improvements are needed for processing renewable feedstocks to produce diesel or jet fuels with increased branched paraffin content to lower their corresponding cloud and / or freeze points.

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