Low Ammoina Liquid in the receiver

[cool king2007]

Hi everybody,


I have Ammonia plant consist of two stage (low stage -450C and high stage -60C), we use low stage for cold room storage , Hardening tunnel and high stage for glycol plate heat exchanger this second one for pasteurization , milk tanks and aircon …etc and we use high pressure liquid from receiver to feed ice cream freezers. Our problem appear when we run one or two freezer only with out Hardening tunnel there is no liquid in the receiver , I mean the plant runs as low capacity most of the compressor standby there is no condensation , Actually we add ammonia but we didn't get perfect solution. Now we are thinking to add pre-receiver to feed ice cream freezers I don't know if this procedure will solve our problem. So I need your advice to solve this problem


Thanks

[RANGER1]

cool king ,
Could be a number of problems but need more information .

Is hardening tunnel fed from liquid reciever as well ?
Have you got any indications where liquid dissappears to when it is off .

What size is your plant & does it have any liquid overfeed system or all high pressure liquid from reciever?

Does liquid reciever have balance line from main discharge header?

Tell us what you can

[cool king2007]

cool king ,
Could be a number of problems but need more information .

Is hardening tunnel fed from liquid reciever as well ?
Have you got any indications where liquid dissappears to when it is off .

What size is your plant & does it have any liquid overfeed system or all high pressure liquid from reciever?

Does liquid reciever have balance line from main discharge header?

Tell us what you can
RANGER1,
Thanks for your reply
Hardening tunnels feed from -45degree centigrade ammonia separator.
I think at ammonia separators because they have low level control and they take ammonia from receiver.
What do you mean by plant size? and what is liquid overfeed system stand for? is it like pre-receiver?
All high pressure liquid from receiver.
Yes, liquid receiver has balance line from main discharge header.
Regards

[Sandro Baptista]

Hi everybody,


I have Ammonia plant consist of two stage (low stage -450C and high stage -60C), we use low stage for cold room storage , Hardening tunnel and high stage for glycol plate heat exchanger this second one for pasteurization , milk tanks and aircon …etc and we use high pressure liquid from receiver to feed ice cream freezers. Our problem appear when we run one or two freezer only with out Hardening tunnel there is no liquid in the receiver , I mean the plant runs as low capacity most of the compressor standby there is no condensation , Actually we add ammonia but we didn't get perfect solution. Now we are thinking to add pre-receiver to feed ice cream freezers I don't know if this procedure will solve our problem. So I need your advice to solve this problem


Thanks



When you run everything else except the two freezers everything runs nice?

[RANGER1]

cool king,
Liquid overfeed is where you have a vessel with liquid ammonia pumps.

These pumps circulate ammonia out into plant evaporators etc.

Most of it returs as liquid back into vessel & some as gas which compressor draws off.

So if you have this type of vessel , is the level in this rise when hardening room is off or stay the same .
Note main high pressure liquid reciever feeds level in this vessel usually with float valves
controlling solonoid valve

[Sandro Baptista]

Besides the hardening tunnel and cold room stores you also have freezers at the low stage, is that it?

Does the freezers are feed by the same liquid separator that also serves the cold stores and the hardening tunnel?

[Segei]

Liquid solenoids to hardening tunnel may leak. Try to run hardening tunnel fans on hand. If liquid return, solenoids have leaks.

[cool king2007]

When you run everything else except the two freezers everything runs nice?
Our Ammonia plant stand for ice cream factory this factory has two hardening tunnels (-40C), six cold room stores (-25C), corridor evaporator (5C), six ammonia freezers and plate heat exchanger(600KW)works by ammonia.
the six cold stores and corridor evaporator always run, when we run freezer or two even all freezers without hardening tunnels or pasteurization the freezers do not run Properly because there is no liquid at the receiver so we have to run hardening tunnels or pasteurization even we do not use them to make liquid. sometimes we when run some of freezers with one hardening tunnel this is not useful so we have to run the second one without use,so when everything run the freezers run nice
Regards

[cool king2007]

Besides the hardening tunnel and cold room stores you also have freezers at the low stage, is that it?

Does the freezers are feed by the same liquid separator that also serves the cold stores and the hardening tunnel?
Yes, hardening tunnels, cold room stores and freezers at low stage But the freezers feed by high pressure liquid from receiver

[cool king2007]

cool king,
Liquid overfeed is where you have a vessel with liquid ammonia pumps.

These pumps circulate ammonia out into plant evaporators etc.

Most of it returs as liquid back into vessel & some as gas which compressor draws off.

So if you have this type of vessel , is the level in this rise when hardening room is off or stay the same .
Note main high pressure liquid reciever feeds level in this vessel usually with float valves
controlling solonoid valve
RANGER1,
the level sometimes rise at ammonia separator when hardening tunnels are off.
regards

[Sandro Baptista]

My thoughts are that the evaporators belong to the hardening tunnels and/or pasteurization have the solenoid valves from the pumped liquid with bad sealing so the liquid flood those evaporators when they are off.

Try to do the following and the please tell us the results: close the liquid stop valve from that evaporators and let them works about 15 min...20 min. The let the valves closed and see what happen. If the liquid level receiver goes to normal replace those solenoid valves or apply its sealing spares kit.

[Sandro Baptista]

Cool king,

Any results you can tell us?

[cool king2007]

Sandro Baptista,
unfortunately the problem still as before.
what about if we install another receiver ( small pre-receiver) to feed freezers?
Thanks & Regards

[Sandro Baptista]

Did you close the stop liquid valve and open the respective automatic suction valve and the turn on the hardening tunnels and/or pasteurization during 15...20 min?

I fargot to mentioned about the suction valves.

[cool king2007]

yes, i close stop liquid valve but we do not have automatic suction valve only stop valve on suction line and it always open

[cool king2007]

Sandro Baptista,
Can you send me your private E-mail to send you our Ammonia plant drawings.

E-mail : ben_ali1983@yahoo.com
Phone: 00218926865280

[Sandro Baptista]

yes, i close stop liquid valve but we do not have automatic suction valve only stop valve on suction line and it always open


If you have always the suction valve always open unless the leak at the inlet be great you should have almost liquid NH3 inside that evaporators...so I don't understand.
If you say that when you ON the hardening tunnels the liquid miraculously appears the only way I see it is the liquid is inside the coil. You also told me the hardening tunnels share the same liquid separator so where could be the liquid?

...hmmm...Don't you have always to operate with the pasteurization to get the liquid for the other services??
If you only operating with the hardenning tunnels without the pasteurization you are sure you can "get" liquid?

[Segei]

Did you try to run fans of this tunnel on hand mode(as I suggested you)? Most likely tunnel evaporators are full of liquid ammonia.

[cool king2007]

Segei,
yes, i run fans of these tunnels on hand mode about 25 min.

[cool king2007]

If you have always the suction valve always open unless the leak at the inlet be great you should have almost liquid NH3 inside that evaporators...so I don't understand.
If you say that when you ON the hardening tunnels the liquid miraculously appears the only way I see it is the liquid is inside the coil. You also told me the hardening tunnels share the same liquid separator so where could be the liquid?

...hmmm...Don't you have always to operate with the pasteurization to get the liquid for the other services??
If you only operating with the hardenning tunnels without the pasteurization you are sure you can "get" liquid?
*Please see attached picture, this picture shows ice on the coil of hardening tunnel when there is leakage in liquid solenoid valve at inlet line but we changed it and now ok this happened in the past, I mean if liquid solenoid valve leak this will make ice on the coil, won't it?.
*The hardening tunnels feed from (-45degree centigrade) ammonia separator, while freezers feed from HP receiver.
*Sometimes i have to operate plate heat exchanger of pasteurization to make more load on high stage compressors Because when you start with one hardening tunnel the level goes rise in the HP receiver and when the hardening tunnel gets its setpoint temperature the level comes down because high stage compressors goes to standby not all of them maybe will stay one compressor sometimes not with 100% capacity, and this is not enough to make liquid at HP receiver that's why i have to operate another hardening tunnel and/or PHE of pasteurization.
I like to say maybe there is something wrong with our ammonia plant control (the way of control) or design

[Sandro Baptista]

*Please see attached picture, this picture shows ice on the coil of hardening tunnel when there is leakage in liquid solenoid valve at inlet line but we changed it and now ok this happened in the past, I mean if liquid solenoid valve leak this will make ice on the coil, won't it?.
*The hardening tunnels feed from (-45degree centigrade) ammonia separator, while freezers feed from HP receiver.
*Sometimes i have to operate plate heat exchanger of pasteurization to make more load on high stage compressors Because when you start with one hardening tunnel the level goes rise in the HP receiver and when the hardening tunnel gets its setpoint temperature the level comes down because high stage compressors goes to standby not all of them maybe will stay one compressor sometimes not with 100% capacity, and this is not enough to make liquid at HP receiver that's why i have to operate another hardening tunnel and/or PHE of pasteurization.
I like to say maybe there is something wrong with our ammonia plant control (the way of control) or design

Can you please send us the diagram of the plant? More thoughts I have but I would prefer first see the diagram if you don't mind.

[cool king2007]

Sandro Baptista,
I tried to send you our ammonia plant diagram but my file KB bytes exceeds the forum's limit, so can you send me your E-mail if you don't mind
Regards.

E-mail: ben_ali1983@yahoo.com
Phone: 00218926865280

[Sandro Baptista]

Sandro Baptista,
I tried to send you our ammonia plant diagram but my file KB bytes exceeds the forum's limit, so can you send me your E-mail if you don't mind
Regards.

E-mail: ben_ali1983@yahoo.com
Phone: 00218926865280

I already had sent you. Is it ben_ali1983@yahoo.com, right?

[Sandro Baptista]

Does the hardening tunnels have it's own liquid separators? They might be big enough to "suck" and accumulate much liquid from the receiver when the hardening tunnel is stopped. The valve feeding liquid could be leaking. See if the level rises at the separators or closes the stop valve at the feeding inlet of the separator and then ON just after the hardening tunnel have done its job.

The same can be happening with the pasteurization.

Do the freezers and cold stores (-25ºC) share the same feeding system? If is that when the freezers go wrong so the cold stores should have lack of R717 at their evaporators.

[cool king2007]

I already had sent you. Is it ben_ali1983@yahoo.com, right?
Sandro Baptista,
your E-mail didn't arrive to me please try to send it again.
Thanks a lot

[Terron]

Cool King 2007, have you figured out this problem yet?

[Terron]

If not; Is it a long run to your freezers from the receiver? What are your system pressures during the problem? Have you pulled all your ammonia back to the receiver to get an accurate level reading? Did you charge the system under full load operations and with your Accumulators (not evaps) satisfied? Have you throttled down you HEV's on the freezer units to slow down the consumption of ammonia being feed to them? It sounds like When your running the hardening tunnels they recirculate more than enough liquid to keep the low side accumulator running smoothly and enough heat load to have your condenser satisfy your receiver.

[Sandro Baptista]

Sandro Baptista,
your E-mail didn't arrive to me please try to send it again.
Thanks a lot


Hi cool king2007,

I have received your email and I have answer you two days ago.

Do you confirm the reception of the email I sent to you?

[cool king2007]

Hi cool king2007,

I have received your email and I have answer you two days ago.

Do you confirm the reception of the email I sent to you?
Hi Sandro,
Yes, I received your E-mail and i like to thank you very much. I will reply to you as soon as possible, Please let me know if you have another notes or advices.
E-mail: ben_ali1983@yahoo.com
Phone: 00218926865280

[Sandro Baptista]

Hi Sandro,
Yes, I received your E-mail and i like to thank you very much. I will reply to you as soon as possible, Please let me know if you have another notes or advices.
E-mail: ben_ali1983@yahoo.com
Phone: 00218926865280


Any news or developments?

[Sandro Baptista]

I'm worry with your refrigeration plant. Still waiting more developments.

Wish you a Happy New Year.

[cool king2007]

Hello everybody


Finally our problem is solved , The reason was (By bass stop valve) between receiver and high stage separator, it was a little open so the liquid was passing to high stage separator without control. This valve was a little open from the beginning so no body imagine that it maybe a reason. Now we have liquid level in our receiver and because the ice cream factory nowadays is stopped because winter season so we have to wait until summer to check if the level ok or not. Actually I like to say many thanks to every body


Regards