Methods for preparing fuel compositions from renewable sources, and related systems

1. A method for producing a fuel composition from a feedstock that includes biomass, municipal solid waste (MSW), or a combination thereof, said method comprising the steps of:

pyrolyzing the feedstock in the presence of a transition metal using microwave energy, wherein a level of oxygen in at least one pyrolysis product is reduced, and wherein the transition metal is oxidized to form a transition metal oxide; and

regenerating the transition metal by subjecting the transition metal oxide to a reduction reaction in a regeneration reactor, wherein regeneration of the transition metal is carried out by a reduction reaction which reduces the transition metal oxide, and wherein at least a portion of the energy required for the reduction reaction is supplied by combustion of at least one pyrolysis product.

2. The method of claim 1 , wherein the pyrolysis is carried out under plasma conditions, using the microwave energy.

3. The method of claim 1 , wherein the transition metal is selected from the group consisting of copper, nickel, cobalt, manganese, iron, and zinc.

4. The method of claim 1 , wherein the transition metal is iron.

5. The method of claim 1 , wherein the feedstock, prior to pyrolysis, contains oxygen at a level of 10% to about 50%, based on the total solids weight of the feedstock.

6. The method of claim 1 , wherein the feedstock contains a pre-determined amount of oxygen before pyrolysis; and after pyrolysis, the amount of oxygen has been reduced by at least about 50% of the amount before pyrolysis.

7. The method of claim 1 , wherein pyrolysis of the feedstock produces a composition comprising bio-oils, light hydrocarbons, and char.

8. The method of claim 1 , wherein the at least one pyrolysis product which is combusted for the reduction reaction comprises light hydrocarbons.

9. The method of claim 1 , wherein at least a portion of the pyrolysis product is subjected to at least one upgrading step.

10. The method of claim 9 , wherein the upgrading step comprises hydro-treating.

11. The method of claim 10 , wherein the hydro-treating step is followed by a hydro-isomerization step.

12. The method of claim 11 , wherein the hydro-isomerization step is followed by at least one separation step, to separate at least some of the isomerization products.

13. An integrated process for producing a fuel composition from a feedstock material that includes at least one of biomass and municipal solid waste, the process comprising the steps of:

a) pyrolyzing the feedstock in the presence of a transition metal using microwave energy, wherein a level of oxygen in at least one pyrolysis product is reduced, and wherein the transition metal is oxidized to form a transition metal oxide;

wherein the at least one pyrolysis product comprises bio-oils, light hydrocarbons, and char;

b) regenerating the transition metal by subjecting the transition metal oxide to a reduction reaction in a regeneration reactor, wherein regeneration of the transition metal is carried out by a reduction reaction which reduces the transition metal oxide, and wherein at least a portion of the energy required for the reduction reaction is supplied by combustion of at least one pyrolysis product; and

c) upgrading the bio-oil product to a liquid fuel, by subjecting the bio-oil to an upgrading process comprising hydro-treating, following by hydro-isomerization and separation of isomerization products.

14. A system for producing a fuel composition from a feedstock material that includes at least one of biomass and municipal solid waste (MSW), the system comprising:

(i) a pyrolysis reactor, adapted to accept a feedstock of biomass or municipal solid waste (MSW), or combinations thereof; and to convert the feedstock to pyrolysis products in the presence of a transition metal;

(ii) a microwave source adapted to supply microwave energy to the pyrolysis reactor;

(iii) a regeneration reactor in communication with the pyrolysis reactor, to supply a selected amount of the transition metal during pyrolysis by regenerating the transition metal in a reduction reaction, wherein at least a portion of the energy required for the reduction reaction is supplied by combustion of at least one pyrolysis product; and

(iv) at least one upgrading unit in communication with the pyrolysis reactor, to convert at least one of the pyrolysis products to a liquid fuel composition.