9 replies to this topic

[neriet]

I need to define the amount of inhibitor to use in order to avoid such problems as hydrate formation, ice formation etc. with natural gas, there are several lines to be monitored, on each line there is a GC (C1..C6+), actually we run a simulator to estimate the required amount of inhibitor, we would prefer a realtime solution able to control the amount of inhibitor, is there anything similar to dew point instruments available for hydrates ? As alternative a software to estimate hydrate formation to link with GC instruments ?

[marchem]

I do not know inline instruments capable
to estimate hydrate formation conditions
but you may utilize a soft sensor,

a soft sensor can be provided
installed in a little PC
which you may install in control room
or locally in GC cabinets etc.

soft sensors operate in realtime
exchanging data via OPC or MODBUS
interfaces (which are the standard
interfaces for industrial applications).

Typically you provide compositions
(from GC) and the soft sensor
calculates the required properties
the procedures are the same of simulators
and accuracy are equivalent.

I have utilized this,

http://www.prode.com...hydrocarbon.htm

which is capable to calculate hydrate formation
conditions with different amounts of inhibitors

Edited by marchem, 15 September 2013 - 02:09 PM.

[neriet]

thanks for the information.

[PaoloPemi]

as said by marchem,

with PRODE SERVER you can calculate in realtime hydrate formation conditions 

(as well as many other properties as dew points, water condensation etc.),

 

however the software itself doesn't calculate the required amount of inhibitors,

instead,

if you specify an amount of inhibitor,

it estimates the conditions for hydrate formation.

[neriet]

thanks,

does PRODE SERVER calculate hydrates
plus hydrocarbons and water dew point ?

In their page there is a version which
could be installed in our DCS system.

Edited by neriet, 27 September 2013 - 06:10 AM.

[PaoloPemi]

yes,

given the composition

you can get more than 30 different properties

including hydrates and

hydrocarbons + water dew point,

the main advantages of soft sensors

are that they don't require maintenance,

and can estimate many properties

which differently may be difficult or

expensive to measure with

traditional methods,

examples are hydrates formation,

true critical points etc.

Once you have filled the soft sensor

with required data (w,t,p)  it calculates

all the required properties as

dew points.

bubble points,

densities , volumes,

heats of combustion etc. etc.

(see the list on above link)

but it could also be programmed

to control the operating of

colunns , compressors etc.

where a rigorous simulation is required.

The solution may require

a few seconds or less

(depending from the number

of properties to calculate)

so it's a realtime operation.

 

I know of one installation running

(without much problems) since 1998,

the software has been updated, though.

Edited by PaoloPemi, 28 September 2013 - 07:42 AM.

[neriet]

thanks for the information >I know of one installation running >(without much problems) since 1998, >the software has been updated, though. that seems a good reference :-)

[RockDock]

I know ProMax integrates well with PI. There was a plant I visited who had ProMax continuously running every 5 minutes to calculate their hydrate conditions. More specifically, it told them how much MeOH to inject. That may be another option for you.

[AntoninC]

A bit late, but you may want to check: http://www.hydrafact..._hydrachek.html

[neriet]

thanks AntoninC,

we have installed Prode Properties in DCS which calculates dew points plus

hydrate formation condition based on GC readings,

your solution, based on a specific sensor, looks interesting.