Pre-cooling Natural Gas Before Compression

Well, that's one way of doing it. The other is to cool the gas after compression using a smaller heat exchanger and now-available cooling systems. It saves investing in a fridge plant too and the BHP associated with that.

Thanks for the reply. We will be having an inter-stage air cooler to bring down the compression temperatures downstream, however my question is about a pre-cooler selection upstream. The project maximum gas temperatures at suction can be as high as 170 psig. For sizing a recip and driver, the suction temp drives the head requirement, and hence power requirement. Higher power requirements equate to larger compressor frame sizes which is more costly.

Previously you said 170°F; now you say 170psig. There's a big difference! Where does this natural gas come from to have that high a temperature or that high a pressure?

170 F is the suction temp. The "psig" was a typo. Thanks.

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Are there any more typos that the forum should know about, please?

I think Tornado has your only answer, if cooling water is not available.

Talk to JP76, but be prepared for an earful of gobbledygook.

Perish the thought.

Long story short! If you have an abundance of natural gas, why don't you set up a natural gas fired refrigeration system to cool the gas being extracted from wherever you're getting it? Those types of systems have been around for a LONG time and are simple systems with no moving parts.

Do you have any literature I could read up on? Thanks.

Look up Hilsch Vortex Tube.

I don't have any information on its use with natural gas, but the device separates a stream of pressurized gas into two lower pressure streams, one hot, and one cold. The hotter stream could use fins to transfer heat to the atmosphere. It would probably require separate compressors to re-compress the cooled gasses.

I just remembered that you said it was 170°, not 170psig, so you probably do not have enough pressure for the Vortex Tube to work.

The previous poster may have been referring to a gas-fueled refrigeration system. That would burn some of the gas as a source of energy to cool the remainder.

http://en.wikipedia.org/wiki/Absorption_refrigerator

OrigM: along those lines a gas-powered fluid recirculation pump , depending on the WORK to be done, could have a pre-cooling hybrid with last-staging refrigeration/absorption chillers (gas fired, 90-'tons' of gas heat rejected/emitted for every 50 Tons of cooling, net)

? What is the work? what is the volume adn the media-constant over a proposed T1-to- T2?

Bicyc: ( I prefer my first powered by engine-rack behind-the-seat 2hp, belt (3^rd pulley tensioning for 'transmission') -drive to where the pedals were at bicycle frame bearings, a chain-gear sprocket, to rear bolted-on -enlarged sprocket (of that once-connected to those old pedals) 24" bike that did over 15MPH; and then spark-plug zapped you trying to get off ! 1971 - :)

Thank you for your clear question.

What would be the WORK of the load of the temperature 170f gas x how much , for even considering a type or method of cooling a volume of gas?

How many btu's would be exchanged to even accomplish some sizing calculation of say fin-tube air/ or other styles of coolers?

Your first reply did well, reviewing the focus of your question. Thank you. Your use of the word "TEMPERATURE" was clear -

Below is for some homework (links to but a few of hundreds of papers) on COOLER-hybrids. Just ignore the compressors and heat-pumps tied in for your situation to review possibilities.

Process of cooling that is gbl-ty to some who have yet to express the idea to a client, perhaps. MANY though DO UNDERSTAND, or others could understand, -:

PROCESS COOLING has all kinds of meanings out there, but I would reference 'COOLING' as I think you meant. For this note though, -here without any refrigeration system for the first and second stage - hybrid style cooling. Here- a system WITHOUT compressors, nor absorption chillers, -- NONE of that ,

-------but I would like to know how much WORK is to be (btu's?) done.

If you do not have 'clean water' as you mentioned, could fouled water still go through a cleanable exchanger for the cooling/?

and what about a hybrid-Cooler for just if 170f-nGas is to be cooled ? :

or pre-cooling 170f nGas, within a 108f ambient air, -UNLIKELY having clean cooling water, and again, just bring down the temperature of the gas FIRST, as you clearly indicated, : --------- but with Air, and too, the Earth-ground-looping of a cooler fluid, or directly Earth-Tubes acceptable for direct contact , containing the gas alone? - There are limitations with damp-ground-conductivity arrangements. Dry ground works poorly, but maybe for high temp differentials, still allows heat energy to do its thing: MOVE.

Oh, look. The random technical phrase generator. Right on cue.

Here are some Hybrid links (only for considering Process-Pre-Cooling, though):

In 1980 the Swede's had cross sectional views of large cardioid shaped drying of the ground around a once-damp-ground containing a cistern (top insulated, 5ft deep below a grade) which was used for STORING heat in an Earth-Exchange absorption of a solar collector system. Numbers of how big and how much were listed about the WORK available, and about the TOTAL WORK of the Heat Energy exchanged.

---Do you have a number of BTU's - (even a relative guess)?

Could there be any particular pressure in cooling would there be a possible change in state from a gas brought to a liquid state at some pressure-temp point ? Volume/hour? T1 to some T2? Pressure in pre-cooler-?

(Media Flowing X Temp X (any constant) for to = BTUh ?)

The GEO-gblty:)

What if any damp-conductive-earth below grade for a type of GEOTHERMAL -ECL, gle- absorption of Heat Energy is at all available at the site-? GEOEXCHANGE? -Hybrid with air cooling, as well?

Ditches, Pond, Horizontal boring, vertical boring, wet (high static water-level-vertical-wells) vertical-recirculation in/out of a same well- Boreholes, grouted properly, -damp/ any systems of a damp-conductive nature, at say even 4ft depths (7, and 8ft ditches) and under the 108 ambient air above,

and IF the btuh's can not all be exchanged with a (far less expensive, but limited) DRY COOLER of some exchanger/ fin-tubes for one style, - then perhaps an Earth Collector receiving some energy may be a hybrid adaptation for you. (BTU's/hour ? temp X volume of nGas X constant(s) ?)

REMOVE the compressor, the refrigeration/heat-pump, or other machinery --- and leave the idea of a SIMPLE cooing-fluid-recirculator pump, - ONLY.

(This may look simple, but you will see for a need to be redundant about that in conversation - until someone says "What do ya mean?!")

? air pre cooling, ?Earth-Exchange (heating the ground), then other air- or ground-looped chiller that is REJECTING/admitting heat-energy to a pond, or other unclean-water-source, or just the GEO-Ground in an oversized, lame, plastic tubing (PE 3408- sdr-11) heat-exchanger that is fitting the WORK to be done.

Some of many heat-exchange links:)

http://geoheat.oit.edu/bulletin/bull30-1/art3.pdf (but look at NO COMPRESSORS, first)

http://www1.eere.energy.gov/femp/pdfs/hyhgp_tir.pdf (without heat-pumps chilling , nor chillers , -first)

http://intraweb.stockton.edu/eyos/energy_studies/content/docs/proceedings/SINGH.PDF

Current engineering design manuals such as Caneta Research, (1995), Kavanaugh and Rafferty (1997), Kavanaugh (1998), and ASHRAE (2003), developed from research conducted since the 1980s, mention the potential use of hybrid cooling tower/fluid cooler GHP systems

and vertical to horizontal boring for any hybrid Earth-Coupling ECL, gle loops have to be in a damp-conductive condition that has limitations that many engineers can discuss:

http://www.researchgate.net/publication/229017138_Performance_evaluation_of_standing_column_well_for_potential_application_of_ground_source_heat_pump_in_Jordan

: JUST for your nGAS , ? air - cooled first, and perhaps Earth-Cooled , without a 'chiller'/ GEO-ground-source, unless that 3rd additions would augment your needs, but for--- COOLING a media, and within HOW MUCH WORK ? (Btuh's?)

As if the first load of gobbledygook weren't enough.

Can any reader translate at all, please?

JP76,
Without knowing every bit of information involved we can just scratch the surface of the posters needs. I think the information posted will give him a good starting point, however there is going to be a lot of engineering involved in making it happen.

Thank you for agreeing.

If I do not know the WORK, how can I begin to "size" up.

I start with the total work, volume, the media X temp diff point T1 to T2, then any constants already available.

The dry cooler or the Earth Cooler may be 20-tons or 2000, as one is in Cananda (and larger).

The work needed is the difference in enthalpy of the finish state and the start state, multiplied by the flowrate. One doesn't save power by using chilled water over cooling water, for example.

It doesn't matter whether the utility is at any particular temperature, as that number merely determines the heat exchange equipment sizing. The only thing about cooling water is that the inlet temperature to the equipment is dependent on local wet-bulb temperatures at any particular time of day.

It still sounds as though a Chemical Engineer is needed pronto. So get dialling and hiring.

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I am , as you may realize by now, not probably seeing your definition then of cooling water and chilled water.

Refrigerated chilled water in 108 ambient would operate nearly 7 x's more expensive per ton of exchange installed and recirculated, compared to an Earth-Coupled cooler that can do a same amount of work. (presuming ~ 60-degree Earth, 10 to 12ft depths, peak hotter month)

but even sand at that depth would save, but not enough info to see if we even would call the excavator/driller, -or even the tower rep.

Hybrid---? with a simple temp-diff controller and a dry cooler and / or adding a cooling tower can be even more savings (or a best system) if we knew the WORK beyond any formulas.

I say too, call, and also call an accountant and Engineer to evaluate, as well. (PS I marked yours "good" , and thank you).

Why don't you ran the gas through the unit cooler (add a precooler section). You might have some problem during the start up of the unit, but once the fin-fan cooler starts to work (engine driven), you should be able to drop the temperature to an acceptable level. I have also heard that in some places they use a close circuit glycol radiator and use it for a gas-to-glycol vessel type (liquid bath) heat exchanger system to cool the gas. You still need to cool down the glycol in the fin-fan cooler to recirculate it.