Digestor new top

[jondear]

A digestor near to us the last few days has had a crane in the top disappeared after half a day and then 24hrs later it was back .
I'm just curious what are they made of .Why would you remove it ?Leaking gas !Need to get inside for something maybe .

 

[sjt01]

Possibly a broken down stirrer. Some of the concrete tanks have roof segments that lift in the event of an overfill or foaming, and need replacing by crane.
Our tank is a Permastore steel and has gas mixing, but we had to replace a small hatch on top as the stainless steel had corroded away.

 

[kill]

Would grit or solids ever need to be removed?

 

[sjt01]

Would grit or solids ever need to be removed?

If there is no provision for grit removal (we have a hopper bottom digester which gets a degrit flush monthly) then grit can build up, particularly if poultry litter is used. It can take 3 months to get back up to full production after emptying the digester, so it is not an operation to be undertaken lightly.

 

[Courier]

Neighbour insisted on installing an extra stirrer in at time of build - Good sense ?

 

[sjt01]

Neighbour insisted on installing an extra stirrer in at time of build - Good sense ?

Stirrers in tanks are a notorious weak spot.

 

[thesilentone]

Fair chance of two scenarios.

1) Complete stirrer installation/replacement
2) Tank needs cleaned out (fairly common after several years operation)

Removing the top has a protocol, so no one is killed or injured, If it's a membrane type, this is fairly easy, and may not need completely removed for the stirrer work.

If a clean out is needed, then removing the whole top is easiest. The clean out could be due to a build up of grit, or the tank has gone dry,and cannot be re-liquefied.

 

[Gee]

the tank has gone dry,and cannot be re-liquefied

Sounds nasty!