Dirty Natural Gas as fuel

[Unotec]

I am planning to change the fuel supply for a treater from propane to natural gas. The plant borders with a booster gas plant for produced natural gas. Obviously this gas is "dirty". Contains water and solids. What would be an effective way to cost-effectively clean this gas stream?

 

[mbeychok]

unotech:

Is the natural gas a raw produced gas from a gas production field? If so, it very probably also contains hydrogen sulfide and, if you are in the USA or many other countries, there are some strict governmental limits on the sulfur content of fuel gas and/or the amount of sulfur dioxide emissions that you will have to meet. Meeting such regulations may be more costly than simply removing water and solids.

Milton Beychok
(Visit me at www.air-dispersion.com)
.

 

[Unotec]

Thanks, but it is sweet gas. So far I am planning to use a strainer and a small knock out drum of some sort.

 

[monaco8774]

You need to get liquids out and solids so strainer (15 microns) and knock out drum (with demister) will be needed, however you can get condensation of hydrocarbon in the lines so normally you need around 20°C of superheat in the gas. It will depend entirely on what the gas composition is and what pressure your letting it down to / from. Whats required would range from nothing through a heat traced and insulated gas line downstream of the scrubber through to a heater. It also depends what your using the gas in, if its a boiler it hardly needs any treatment but if its a dry low emmisions turbine you need the full spec.

 

[Unotec]

Thanks

 

[mbeychok]

Unotech:

If you do use a vapor-liquid separator, see faq798-1153 for how to design one.

Milton Beychok
(Visit me at www.air-dispersion.com)
.

 

[TD2K]

A treater likely won't require any specialized fuel conditioning. Refinery gases can run wet and typically, all they will have is a battery limit KO pot before going to fired heaters.

Now, as mentioned, if you have strict emission requirements and have low NOx burners, you should check with the burner vendor, low NOx burners can be pretty touchy about their fuel quality.