Method of processing algae, carbonaceous feedstocks, and their mixtures to biocrude and its conversion into biofuel products

Abstract

The present invention relates to an integrated method for processing algal biomass comprising a marine algal strain or a freshwater (non-marine) algal strain or a plurality of marine algal strains or a plurality of freshwater (non-marine) algal strains or any combination thereof or other carbonaceous feedstocks like biosolids or any combination of algae/algae mixtures and carbonaceous feedstocks to produce biofuel. The method includes subjecting the algae/algal mixture to hydrothermal liquefaction/co-liquefaction using sub-critical water to produce a biocrude. The biocrude is pretreated using a renewable biocatalyst to remove impurities which include Nitrogen (N), Sulfur (S), Oxygen (O) and salts and the pretreated biocrude is mixed with heteroatoms a petrocrude to form a biocrude-petrocrude blend. The biocrude-petrocrude blend is distilled and the distillate fractions are treated using the renewable biocatalyst to remove impurities and finally hydrotreated to produce fractions biofuels. The recovered biocatalyst/biochar which is rich in nutrients is used for agricultural applications to improve soil fertility.

1 . A method for processing algal biomass comprising a marine algal strain or a freshwater (non-marine) algal strain or a plurality of marine algal strains or a plurality of freshwater (non-marine) algal strains or any combination thereof or other carbonaceous feedstock or any combination of algae/algae mixtures forming primary feedstock and carbonaceous feedstocks forming secondary feedstocks to produce biofuels and the method comprising:
 (i) mixing said algal biomass along with another algal biomass or mixture of algae or said carbonaceous feedstock or mixtures of carbonaceous feedstock to produce a feedstock mixture;   (ii) subjecting said feedstock mixture containing algae/carbonaceous material to hydrothermal liquefaction or co-liquefaction to produce a biocrude;   (iii) pre-treating said biocrude and petrocrude with said renewable biocatalyst (biochar) to remove impurities and heteroatoms;   (iv) pretreating said biocrude and petrocrude by water washing for desalting;   (v) blending said biocrude with petrocrude;   (vi) pre-treating said biocrude-petrocrude blend with said renewable biocatalyst to remove impurities and heteroatoms;   (vii) distilling said biocrude-petrocrude blend to produce distillate fractions   (viii) treating said distillate fuel fractions derived from algal biocrude or blend of algal biocrude and petrocrude with said renewable biocatalyst to remove further impurities and heteroatoms;   (ix) Hydrotreating said distillate fractions to produce drop in fuels;   (x) recycling the recovered renewable catalyst   (xi) Utilising the recovered renewable catalyst as soil amendment for agricultural applications.   (xii) producing drop-in biofuels from algae, carbonaceous feedstocks and their mixtures through an INTEGRATED PROCESS/METHOD involving the following steps: [i] producing biocrude through Hydrothermal liquefaction/co-liquefaction;[ii] using of renewable biocatalyst (biochar) to remove heteroatoms in said biocrude/biocrude blend [iii] washing said biocrude/biocrude blend with water for desalting [iv] blending said biocrude and petrocrude for distillation [v] removing heteroatoms/impurities from said biocrude blend using said renewable biocatalyst [vi] removing said heteroatoms/impurities in distillate fractions obtained from said biocrude/biocrude blend using said renewable biocatalyst [vii] hydrotreating/upgradation of distillate fuel fractions to drop-in fuels and [viii] recycling of biocatalysts (biochar) for agricultural application.   
     
     
         2 . The method of  claim 1 , wherein said hydrothermal liquefaction/co-liquefaction is carried out at a temperature of 250-350° C. for 5-30 min at 40-200 bar pressure 
     
     
         3 . The method of  claim 1 , wherein said hydrothermal liquefaction/co-liquefaction is carried out using the feedstock mixture with 10-20% solids w/v. 
     
     
         4 . The method of claim  01 , wherein said algal biocrude and petrocrude blending ratio is selected from 1:9, 0.5:9.5, 1.5:8.5, 2:8, 2.5:7.5, 3:7, 3.5:6.5, 4:6, 4.5:5.5, 5:5, 5.5:4.5, 6:4, 6.5:3.5, 7:3, 610 7.5:2.5, 8:2, 8.5:1.5, 9:1 and 9.5:0.5. 
     
     
         5 . The method according to claim  01 , wherein said algal strains belong to the taxonomic classes of Chlorophyceae (Green algae), Cryptophyceae, Phaeophyceae (Brown algae), Rhodophyceae (Red algae), Xanthophyceae (Yellow-green algae), Dinophyceae, Bacillariophyceae (Diatoms), Chloromonadineae, Eugleniae, Chrysophyceae, and Cyanophyceae/Myxophyceae (Blue green algae or cyanobacteria) 
     
     
         6 . The method according to claim  01 , wherein said carbonaceous feedstocks is selected from a group of biosolids, yeast sludge, municipal sewage sludge, municipal solid waste (MSW), manures, lignite, coal, agricultural wastes, water hyacinth, duck weed and industrial wastes. 
     
     
         7 . A method according to claim  01 , wherein said feedstock mixture include: (i) specific strains of freshwater or marine algal biomass; (ii) specific carbonaceous feedstock alone;(iii) specific carbonaceous feedstock in combination with other carbonaceous feedstocks; (iv) specific strain of algae with the biomass derived from other algal strain; (v) specific strain of algae with the biomass derived from mixed culture of algae; (vi) specific strain of algae with a specific carbonaceous feedstock; (vii) specific strain of algae with a mixture of carbonaceous feedstocks; (viii) mixture of algae with a specific carbonaceous feedstock; and (xi) mixture of algae with mixture of carbonaceous feedstocks 
     
     
         8 . The method according to claim  01 , wherein said renewable biocatalyst is biochar. 
     
     
         9 . The method according to claim  08 , wherein said biochar is obtained from rice bran, peanut hull, manures, animal wastes, pressmud/filter cake, pine, saw dust, bagasse, coconut shell, coir pith, wheat straw, paddy straw, maize cobs and sugarcane trash. 
     
     
         10 . The method according to claim  01 , wherein said impurities include heteroatoms, such as N, O and S and salts. 
     
     
         11 . The method according to claim  01 , wherein said recovered renewable catalyst is used for agricultural applications. 
     
     
         12 . The method according to claim  01 , wherein said primary feedstock of algae or algal mixtures are mixed with said secondary feedstocks at a ratio selected from 90:10, 80:20, 70:30, 60:40, 50:50, 40:60, 30:70, 20:80 and 10:90 for said hydrothermal co-liquefaction.