BE881915A

BE881915A - METHOD FOR WINNING METHANE GAS

Info

Publication number: BE881915A
Application number: BE2/58427A
Authority: BE
Original assignee: Studiebureau O De Koninckx N V; Univ Gent
Priority date: 1980-02-26
Filing date: 1980-02-26
Publication date: 1980-08-26

Description

       

  "Werkwijze voor het winnen van methaangas" Deze uitvinding heeft betrekking op een werkwijze voor

  
het winnen van methaangas, met andere woorden een werkwijze waarbij organisch materiaal, van biologische of xenobiologische oorsprong, dat zich in vaste, vloeibare, opgeloste of andere vorm bevindt, op bekende wijze wordt omgezet tot methaangas door micro-organismen, meer speciaal bakteriën en ééncelligen of

  
door biochemische komponenten die daarvan zijn afgeleid.

  
Zulk methaangas kan in een aanzienlijk aantal toepassingen worden gewonnen zoals, o.a.:
- bij de vergisting van slib in afvalwaterzuiveringsstations;
- bij de vergisting van gekoncentreerde afvalwaters in de bioindustrie en de aanverwante industrieën;
- bij de vergisting van frakties uit huisvuil;
- bij de vergisting van mest uit varkenskwekerijen, runderkwekerijen, enz...;
- bij de vergisting van speciaal daartoe gekweekte zogenaamde "energiegewassen" voor de produktie van methaangas, enz....

  
Bij al deze toepassingen kan de gistingstank in uitvoering variëren van de konventionele mengreaktor tot de anaërobe kontaktreaktor, het anaërobe filter of de moderne opstroomreaktor of nog om het even welke andere vorm.

  
Men weet dat de methaangisting normaal zodanig wordt uitgevoerd dat het gas onder een kleine overdruk, begrepen tussen

  
10 en 100 cm waterkolom, wordt opgevangen waardoor in de reaktorruimte een overdruk aan methaangas heerst.

  
De werkwijze volgens de uitvinding bestaat erin, in tegenstelling met de tot op heden algemeen toegepaste werkwijze,

  
dat er in de ruimte waarin het methaangistingsproces wordt voltrokken steeds een onderdruk heerst die bijvoorbeeld zal variëren tussen 0 en 0,5 atmosfeer, waardoor men verkrijgt dat de gisting met 10 tot 50% wordt versneld.



  This invention relates to a process for

  
the extraction of methane gas, in other words a method in which organic material, of biological or xenobiological origin, which is in solid, liquid, dissolved or other form, is converted into methane gas in known manner by microorganisms, more specifically bacteria and unicellular organisms or

  
by biochemical components derived from it.

  
Such methane gas can be extracted in a significant number of applications, such as:
- in the digestion of sludge in wastewater treatment stations;
- in the fermentation of concentrated waste waters in the factory farming industry and related industries;
- in the fermentation of fractions from household waste;
- in the fermentation of manure from pig farms, cattle farms, etc ...;
- in the fermentation of specially cultivated so-called "energy crops" for the production of methane gas, etc.

  
In all these applications, the fermentation tank can vary in design from the conventional mixing reactor to the anaerobic contact reactor, the anaerobic filter or the modern upstream reactor or any other form.

  
It is known that the methane fermentation is normally carried out in such a way that the gas is under a small overpressure, included between

  
10 and 100 cm water column, which is collected, causing an excess pressure of methane gas in the reactor space.

  
The method according to the invention consists, in contrast to the method generally applied hitherto,

  
that there is always an underpressure in the room in which the methane fermentation process is carried out, which will for instance vary between 0 and 0.5 atmosphere, whereby the fermentation is obtained to be accelerated by 10 to 50%.

Claims

This underpressure will be obtained, for example, by suitably collecting or discharging the methane gas generated.

This method was fully tested on a laboratory scale, using pressures ranging from 1 to 5 meters in water column, whereby increasing the reaction rate, as a result of the aforementioned underpressure, resulted in an overproduction of methane gas that goes up to 50% expressed in < EMI ID = 1.1>

Increasing the reaction rate when applying the above-mentioned underpressure therefore has the consequence that in a fermentation tank with a certain volume the gas production in Nm <3> / h will increase, that is to say that for a certain reaction time the total volume of gas produced will increase. increase or in other words the degree of conversion of the organic substances, in other words the efficiency, will increase.

In practice, a certain degree of conversion or efficiency is usually set as the goal, so that the advantage of applying negative pressure will translate into smaller reactor volumes in order to achieve the same efficiency. Incidentally, initial calculations show that for the same efficiency, the reactor volume could be one third smaller. Since the reactor volume in methane fermentation is by far the largest investment cost

this is a very important advantage for the economics of the process.

REQUIREMENTS

1. Method for the extraction of methane gas, characterized in that an underpressure is created in the space in which the methane fermentation process is carried out.

2.- Method according to requirement 1, characterized in that the above-mentioned negative pressure is comprised between 0 and 0.5 atmospheres.

Method according to requirement 1 or 2, characterized in that the above-mentioned underpressure is obtained by extracting the recovered methane gas.

4.- Method for recovering methane gas, mainly as described previously.