Process for enhancing biogenic methane production from a carbonaceous material using a nutrient composition with low nitrogen/high phosphorus concentrations

Patent metadata

Field	Value
Publication number	US-9796908-B2
Application number	US-201314652945-A
Country	US
Kind code	B2
Filing date	Dec 19, 2013
Priority date	Dec 19, 2012
Publication date	Oct 24, 2017
Grant date	Oct 24, 2017

Abstract

A nutrient composition for enhancing biogenic methane production from a carbonaceous material is described. The nutrient composition comprises a source of phosphorus (P) and a source of nitrogen (N), wherein the molar ratio of phosphorus to nitrogen (P/N) is greater than 1.5, and the nitrogen concentration is at least 0.1 m M and less than 1.7 m M. A process for enhancing biogenic methane production from a carbonaceous material is also described. The process involves contacting the nutrient composition of the invention with the carbonaceous material for a period of time to biogenically produce methane and subsequently collecting methane from the carbonaceous material. The process may further comprise contacting the carbonaceous material with a second nutrient composition, wherein the second nutrient composition has a P/N molar ratio greater than the P/N molar ratio of the former nutrient composition.

First claim

The invention claimed is:

1. A process for enhancing biogenic methane production from a carbonaceous material, the process comprising the steps of:
contacting a first nutrient composition with the carbonaceous material for a period of time to biogenically produce methane, the first nutrient composition comprising a source of phosphorus (P) and a source of nitrogen (N), wherein the molar ratio of phosphorus to nitrogen (P/N) is greater than 2 and the nitrogen concentration is at least 0.1 mM and less than 1 mM; and,
collecting methane from the carbonaceous material,
wherein the carbonaceous material is a carbon-containing substance capable of supporting one or more methanogenic microbial populations, and wherein the carbonaceous material is subject to degradation by the one or more methanogenic microbial populations to produce methane or methane precursors.

2. The process according to claim 1 , further comprising the step of contacting a second nutrient composition with the carbonaceous material for a period of time to biogenically produce methane, said second nutrient composition contacting the carbonaceous material after said first nutrient composition contacts the carbonaceous material.

3. The process according to claim 2 , wherein the second nutrient composition comprises a P/N molar ratio greater than the P/N molar ratio of the first nutrient composition or wherein the second nutrient composition comprises substantially no nitrogen.

4. The process according to claim 2 , wherein the period of time between the contacting of the first and second nutrient compositions with the carbonaceous material is at least 1 week.

5. The process according to claim 2 , wherein the carbonaceous material is an in situ carbonaceous material, and wherein contacting said first and/or second nutrient composition with the carbonaceous material comprises injecting the nutrient composition into or proximal to the in situ carbonaceous material or co-injecting the nutrient composition with a hydraulic fracturing fluid.

6. The process according to claim 1 , wherein the first nutrient composition is delivered by injecting a concentrate to the carbonaceous material, whereby the concentrate undergoes dilution with fluids associated with the carbonaceous material to provide a first nutrient composition having an effective P/N molar ratio greater than 2 and an effective nitrogen concentration of at least 0.1 mM and less than 1 mM.

7. The process according to, claim 1 , wherein, the carbonaceous material is an ex situ carbonaceous material in a heaped pile, and wherein contacting said nutrient composition with the carbonaceous material comprises applying the nutrient composition to an outer surface of the heaped pile in an amount sufficient to cause the nutrient composition to flow or trickle under gravity from the outer surface through underlying carbonaceous material in the heaped pile.

8. The process according to claim 1 , wherein the carbonaceous material is an ex situ carbonaceous material in a reactor, and wherein contacting said nutrient composition with the carbonaceous material comprises mixing the nutrient composition with the carbonaceous material in the reactor.

9. The process according to claim 8 , wherein the mixing is continuous, intermittent, or ceases entirely after an initial mixing period, said period being sufficient to bring the nutrient composition into contact with the carbonaceous material.

10. The process according to claim 1 , wherein the first nutrient composition further comprises one or more methanogenic microbial populations.

11. The process according to claim 1 , wherein the molar ratio of phosphorus to nitrogen (P/N) is less than 8.

12. The process according to claim 1 , wherein the nitrogen concentration is at least 0.2 mM.

13. The process according to claim 1 , wherein the first nutrient composition comprises a phosphorus concentration of at least 1 mM.

14. The process according to claim 1 , wherein the first nutrient composition further comprises at least one trace element selected from the group consisting of iron, manganese, cobalt, zinc, molybdenum, nickel, aluminium, boron, copper, tungsten and selenium, and/or at least one vitamin selected from the group consisting of pyridoxine, aminobenzoic acid, pantothenate, nicotinic acid, riboflavin, thiamine, thioctic acid, biotin, folic acid, pyruvate and B12, and/or at least one additive selected from the group consisting of acids, bases, buffering agents, oxidants, anti-oxidants, surfactants, emulsifying agents, gelling agents, and any combination thereof.

15. The process according to claim 1 , wherein the carbonaceous material is selected from the group consisting of coal, lignite, peat, drill cuttings, waste coal, coal derivatives, oil shale, oil formations, tar sands, hydrocarbon-contaminated soil and petroleum sludges.

16. A process for enhancing biogenic methane production from a carbonaceous material, the process comprising the steps of:
contacting a nutrient composition with the carbonaceous material for a period of time to biogenically produce methane, the nutrient composition comprising a source of phosphorus (P) and a source of nitrogen (N), wherein the molar ratio of phosphorus to nitrogen (P/N) is greater than 1.5 and the nitrogen concentration is at least 0.1 mM and less than 1.7 mM, and,
collecting methane from the carbonaceous material,
wherein the carbonaceous material is a coal deposit, coal, lignite, peat, drill cutting, waste coal, a coal derivative, oil shale, oil formation, tar sand, hydrocarbon-contaminated soil and petroleum sludge, or a combination thereof.

17. The process of claim 16 , wherein the nutrient composition further comprises one or more methanogenic microbial populations.

18. The process of claim 16 , wherein the molar ratio of phosphorus to nitrogen (P/N) is less than 8.

19. The process of claim 16 , wherein nitrogen concentration is at least 0.2 mM.

20. The process of claim 16 , wherein the nitrogen concentration is less than 1.5 mM.

21. The process of claim 16 , wherein the nutrient composition comprises a phosphorus concentration of at least 1 mM.

22. The process of claim 16 , wherein the nutrient composition further comprises at least one trace element selected from the group consisting of iron, manganese, cobalt, zinc, molybdenum, nickel, aluminium, boron, copper, tungsten and selenium, and/or at least one vitamin selected from the group consisting of pyridoxine, aminobenzoic acid, pantothenate, nicotinic acid, riboflavin, thiamine, thioctic acid, biotin, folic acid, pyruvate and B12, and/or at least one additive selected from the group consisting of acids, bases, buffering agents, oxidants, anti-oxidants, surfactants, emulsifying agents, gelling agents, and any combination thereof.

Assignees

• Commw Scient Ind Res Org

Inventors

• Hendry Philip
• Midgley David

Classifications

• Y02E50/30

  Fuel from waste, e.g. synthetic alcohol or diesel · CPC title

• C09K8/62 Primary

  Compositions for forming crevices or fractures · CPC title

• C12P5/023

  Methane · CPC title

• Y02E50/343

  Cross-Sectional Technologies · mapped topic

• E21B43/16

  Enhanced recovery methods for obtaining hydrocarbons · CPC title