3 replies to this topic

[sealittle]

Hello,

 

I am working in the gas processing industry in alberta and have recently been given a project involving a CO2 rich gas stream (85 mol% plus) that is to be compressed and sent to a pipeline where the gas will undergo Joule thompson for recovery of a 95mol% plus CO2 to be used in tertiary recovery of oil fields.

 

I am new to this entire area and would liek to gain some background knowledge on the subject. Could anyone provide me with some sources that may be helpful. Introductory to advanced are greatly appreciated.

 

Also, as a side. It appears we will compress the gas from 500psi to about 1200 psi. I would like to dehydrate this gas as it will be saturated with water to avoid corrosion of the pipeline. Does anyone have any knowledge regarding this particularily?

 

I will be checking back frequently if you would like anymore information.

[gegio1960]

what about temperature, composition and flowrate?

[kkala]

As already noted, more information would result in more specific answers. Following thoughts (subject to criticism)  could be useful in the general case.

1. The compressed gas (1200 psig) will be throttled. Enthalpy will remain same, but temperature will decrease. Final point of CO2 will be on the gas-liquid or gas solid curve (passing from critical and triple point) of temperature-pressure diagram, <http://en.wikipedia....ase_diagram.svg>. Liquid CO2 will be separated from gas easier than solid CO2 (clogging etc). One can investigate whether vapor pressure of CO2 liquid close to its triple point (i.e. close to 5.2 bara, -56 oC) could satisfy extent of CO2 recovery (required 95%). Liquid CO2 will be recovered, its overhead vapor will be taken away with rest gases, e.g. in a flash drum downstream throttling.

Note: <http://www.cheresour...4-co2-pipeline/> can be useful, but does not contain throttling.

2.  It is convenient for engineering calculations to use enthalpies rather than Joule Thomson coefficients. For this you can start from NIST database, <http://webbook.nist....hemistry/fluid/>

3. It is not easy to find specific references, familiarity with flash calculation (thermo, unit operations) and CO2 properties (thermo, even books on physics) could help. Simulation would help, preferably after manual tries. Critical point may be to clarify "process procedure" first, including conditions.

4. A local feasibility study (2002) concerned exploitation of NG deposit containing 22% CO2 (mol/mol). Resulting water condensate was considered corrosive to carbon steel pipe, so the gas was dried (*) in TEG (triethylene glycol) package units, before being introduced to NG pipelines.

 

(*) to - 8 oC water dew point, preliminarily for the feasibility study.

[ankur2061]

sealittle,

 

Carbon Dioxide injection for tertiary recovery from depleted reservoirs is a commonly employed technique of enhanced oil recovery (EOR).

Refer the wikipedia article on carbon dioxide injection for enhanced oil recovery at the following link:

 

http://en.wikipedia....ioxide_flooding

 

TEG Dehydration may be used for CO2 dehydration but with due consideration of the equipment used in TEG dehydration due to carbonic acid formation.

 

Hope this helps.

 

Regards,

Ankur