Method and composition

Abstract

A method of producing a fertiliser composition, the method comprising: (a) providing a composition comprising an amino compound; (b) contacting the composition provided in step (a) with a composition comprising carbon dioxide; and (c) adding a composition comprising cellulosic fibres to the mixture obtained in step (b).

Claims

1. A method of producing a fertilizer composition, the method comprising: (a) providing a composition comprising an amino compound; (b) contacting the composition provided in step (a) with a composition comprising carbon dioxide to obtain a mixture; and (c) adding a composition comprising cellulosic fibers to the mixture obtained in step (b).

2. A method according to claim 1 wherein the composition provided in step (a) comprises ammonia.

3. A method according to claim 1 wherein the composition provided in step (a) comprises an anaerobic digestate.

4. A method according to claim 1 wherein the composition comprising carbon dioxide used in step (b) is a gaseous composition.

5. A method according to claim 4 wherein the composition comprising carbon dioxide comprises exhaust gases from the combustion of a fossil fuel.

6. A method according to claim 4 wherein the composition comprising carbon dioxide comprises biogas.

7. A method according to claim 1 wherein step (c) involves adding a compost material comprising cellulosic fibers to the mixture obtained in step (b).

8. A method according to claim 1 which further involves adding a source of nitrate ion.

9. A method according to claim 8 wherein step (a) involves providing a composition comprising ammonia, a source of nitrate ions and an anaerobic digestate.

10. A method according to claim 1 which further involves adding a source of phosphorus.

11. A method according to claim 1 which further involves a step (d) of further processing the material obtained in step (c).

12. A method according to claim 11 wherein step (d) involves pelletizing the material.

13. A fertilizer composition obtained by the method of claim 1.

14. A fertilizer composition according to claim 13 which comprises 10 to 30 wt % nitrogen.

Description

EXAMPLE 1

(1) A composition of the invention was prepared on an anaerobic digestion (AD) plant according to the following procedure:

(2) Anhydrous ammonia is dissolved in an anaerobic digestate liquor in a dilution mixer to provide an aqueous composition comprising ammonia. This composition is fed to a secondary mixer in which calcium nitrate is dissolved to form a solution A.

(3) Hot flue gases from methane combustion in the AD plant are directed through a heat exchanger where energy is recovered to dry digestate in a digestate dryer.

(4) Solution A is fed to a reaction mixer and flue gases are based through the solution. Carbon dioxide from the flue gases is captured, forming ammonium nitrate and calcium carbonate. The reaction time depends on the concentration of carbon dioxide in the flue gas, but can vary between 10 and 60 minutes. The reaction with carbon dioxide is exothermic, and heat from this reaction is recovered and used to dry digestate.

(5) Dried digestate containing cellulosic fibres (and plant nutrients) is mixed with the solution. In some embodiments extra plant nutrients containing potassium, phosphate and nitrogen may be added from external sources.

(6) The blended fertiliser is granulated, bagged and stored, ready for transport.