DE102011121598A1 - Apparatus useful for simultaneous sterilizing and recovering ammonia from biological residue material, in which biological residue material is simultaneously, thermally sterilized, and ammonia bound to immobile ammonium ions, is recovered - Google Patents

Abstract

Apparatus for simultaneous sterilizing and recovering ammonia from biological residual material, in which the biological residual material is simultaneously, thermally sterilized, and the ammonia bound to immobile ammonium ions, is completely recovered by thermal decomposition, is claimed.

Description

Owing to the oversupply of fermentation residues of biogas plants and liquid manure from livestock farming, there is an increasing desire to process these into transportable and storable fertilizers or fuel. After EU Directive 1069/2009 All animal by-products and fermentation residues of category 1 and 2 placed on the market must be sterilized to protect human and animal health. Sterilization requires 20 minutes of heating to 133 ° C at 3 bar to achieve complete sterility. The process found, the pressure sterilization with subsequent condensation of expelled from the fermentation residue water and the absorption of the gases ammonia and carbon dioxide in the condensate in a single device, provides the greatest possible health protection at the beginning of the treatment process and allows efficient and economical ammonia recovery in one process step. With this procedure, it is possible the ammonia without the use of chemicals such. B. sulfuric acid back to win back. An economic ammonia recovery at the end of a treatment process is technically very complicated with a high degree of dilution in the air without the use of chemicals.

It is generally known that gases are significantly less soluble in hot liquids than in cold ones. Furthermore, it is known that microorganisms die by exposure to high temperatures over a certain period of time. It has been found to perform the sterilization and degassing of the fermentation residues in one step and to recover the escaped gases, in particular ammonia and carbon dioxide as an aqueous solution in a condenser.

After the patent CH 677787 A5 It is known to supply the gases expelled after a pressure heating, in particular ammonia and carbon dioxide to a CHP for combustion. However, this then leads to an increased NOX content in the exhaust gas of the CHP and compliance with the existing exhaust emission limits is considerably more difficult. Furthermore, ammonia is withdrawn as a usable fertilizer the material cycle. One embodiment of ammonia stripping by superheated water under pressure and subsequent condensation of the vapor is in the European patent application EP 0459184 A2 explained. In this embodiment, a sterilization of the entire fermentation residue according to the valid regulations can not be guaranteed and a harmless escape excess, in the condensation of water vapor not absorbed gas primarily carbon dioxide, is not provided. The method found is intended to remedy the disadvantages listed.

The fermentation residue is filled from the fermentation residue storage or another storage tank in a heated pressure vessel. At the same time, a few milliliters of virgin oil are added as a defoamer. The pressure vessel is filled without pressure during the filling process, d. H. that the gas of the container and also during the filling process from the fermentation residue escaping gases, especially insoluble methane can escape. This process is promoted by stirring and the installation of a fan, which supports the removal of methane-containing gas. The gas is preferably fed to the incinerator generally a CHP for combustion. After filling, the container is closed and the fermentation residue is preferably heated with the cooling water of the CHP, which is passed through a double wall chamber. The temperature not to be applied by the cogeneration unit must be controlled by an external heating system. B. electrically or a gas burner, which further heated the heating circuit, are supplied. After sterilization, the pressure vessel is relieved. The advantage of this approach is that the thermally unstable, non-strippable ammonium ions are cleaved to ammonia and a proton. The proton in turn reacts with the carbonic anions, releasing carbon dioxide. Therefore, during this process, all the dissolved gases go into the gas phase and it evaporates so much water until an equilibrium state between the liquid and the gas phase has established. The released gas and the steam are supplied to a condensation. The condenser is cooled. All water-soluble gases dissolve in the condensate until the equilibrium concentration is reached. The condensate can then be used as fertilizer concentrate on. After completion of the condensation process, the degassed fermentation residue is pumped into a receiver for further processing.

Process description.

The fermentation residue is via a lockable line ( 1 ) in the pressure vessel ( 2 ) filled. The air present in the container as well as gases escaping from the fermentation residue can be passed through the line during filling ( 3 ) escape and are preferably fed to the air intake of a CHP. The release of non-soluble gases, especially methane, is promoted by stirring the fermentation residue. The removal of the gas is by installing a fan ( 4 ) and presence of a fresh air supply ( 5 ) supported. At the latest at the end preferably before the end of the filling of the pressure vessel ( 2 ) becomes the filled fermentation residue via a jacket heating ( 6 ), which is fed from the cooling circuit of a CHP, heated and for better heat absorption with a stirrer ( 21 ) is stirred.

Since the fermentation residue with the cooling water of the CHP can not reach the required end temperature of 133 ° C, must be reheated with another heat source. This can be done electrically via installed heating coils ( 15 ) but also with a gas burner ( 16 ) happen. During the afterheating, the cooling water of the CHP cooling circuit via a bypass line ( 17 ) by switching the valve ( 19 ) and closing the valve ( 22 ) on the pressure vessel ( 2 ) passed by. All shut-off devices ( 7 - 11 ) are closed during the entire heating phase, so that the pressure can build up. At the end of the prescribed sterilization time valve ( 10 ) and the water vapor with the gases no longer dissolved in the fermentation residue at the high temperatures flows into the condenser ( 12 ). Since this is a cooling device ( 13 ) is cooled, there condenses the transferred water vapor and the gases also present in particular ammonia and carbon dioxide dissolve until an equilibrium in the condensate. The condensate is stored in a container ( 14 ) collected for further use.

In order to suppress the formation of foam during the heating and the expansion process, the fermentation residue during the filling process of the pressure vessel ( 2 ) a small amount of defoamer ( 19 ) is added. As defoamers, preference is given to using native oils which float on the surface and prevent the formation of stable bubble skins there.

At the end of the degassing process and condensation completed, the fermentation residue is passed through a line ( 18 ) pumped out for further processing (see also ).

LIST OF REFERENCE NUMBERS

1

Inlet pressure vessel

2

pressure vessel

3

Gas line to the CHP

4

Fan

5

Fresh air

6

jacket heating

7

shut-off

8th

shut-off

9

shut-off

10

shut-off

11

shut-off

12

capacitor

13

cooling device

14

container

15

heating coils

16

gas burner

17

Bypass line cooling circuit

18

pressure vessel

19

defoamers

20

Valve

21

stirrer

22

Valve

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• CH 677787 A5 [0003]
• EP 0459184 A2 [0003]

Cited non-patent literature

• EU Directive 1069/2009 [0001]

Claims (1)

Apparatus for the simultaneous sterilization of and ammonia recovery from residual biogenic materials, characterized in that the biogenic residue is thermally sterilized simultaneously and by thermal cleavage of actually immobile ammonium ions contained in them bound ammonia is completely recovered.

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