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Old 5th August 2014, 12:34   #16
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Re: Why do pumps mix LPG with CNG occasionally?

Of late, I have seen this peculiar issue with all CNG outlets in Thane.

The pressure has invariably been over 200 bars.
Ideally, in such a scenario, the Green CNG bar indicator goes on for atleast 30-35 kms before the first light(of the CNG) indicator goes off.

I am paying for the full CNG tank yet what I am effectively getting is lower. Chances are that there is a lot of air mixed in the Gas(though the WR system detects and auto cuts off this) or there is a mix(which is sometimes displayed in CNG pumps) where you end up paying more for a lot lesser gas!!

Now, invariably, my first bar goes off in 10-12 kms which is not a great sign.
There have been times I have got over 225 kms in a tank full.

This problem doesnt really happen in pumps outside Thane though so I guess this is limited to Thane itself.

Anyone else faced this?
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Old 7th August 2014, 14:08   #17
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Re: Why do pumps mix LPG with CNG occasionally?

Quote:
Originally Posted by arnabchak View Post
Of late, I have seen this peculiar issue with all CNG outlets in Thane.

The pressure has invariably been over 200 bars.
Ideally, in such a scenario, the Green CNG bar indicator goes on for atleast 30-35 kms before the first light(of the CNG) indicator goes off.

I am paying for the full CNG tank yet what I am effectively getting is lower. Chances are that there is a lot of air mixed in the Gas(though the WR system detects and auto cuts off this) or there is a mix(which is sometimes displayed in CNG pumps) where you end up paying more for a lot lesser gas!!

Now, invariably, my first bar goes off in 10-12 kms which is not a great sign.
There have been times I have got over 225 kms in a tank full.

This problem doesnt really happen in pumps outside Thane though so I guess this is limited to Thane itself.

Anyone else faced this?
Well, I got the answer to the query I posted.

There is a "mixed" CNG being supplied by MGL after checking with numerous CNG pump attendants.
If you tank up anytime before 8 am, the CNG is "pure".

Post 8 am, it is CNG having traces of LPG.

What this means to the end user:

1) Your car becomes hungry. When you get a tank full at 5 kgs in "pure" CNG, a mix would be at 5.8-6 kgs.

2) The fuel efficiency takes a drastic hit. I invariably get a FE of 22+ kms/kg on my WR. Now, of late, I am getting nothing more than 19 kms/kg

3) Dont know if this is true or myth, mixed CNG helps clean the carbon in the system.
Refer : http://www.carwale.com/forums/28474-cng-gas-mix.html
(Carwale.com). We have a similar thread on our forum as well within the same topic.

The problem is happening since the last 8 days or so.

Hope we get a resolution soon!!!
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Old 9th February 2015, 16:48   #18
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Re: Why do pumps mix LPG with CNG occasionally?

Bumping up an old thread after a long time.
Since the past couple of week, there has been a case of so called mixed gas being supplied by MGL.

For everybodies information, the pumps do not mix anything themselves.
CNG by the nature is a mixture of Methance, notrogen, propane, helium etc..
CNG for automotive use has to have atleast 70% methane.

Since CNG is dierectly supplied from the well, there is no processing or refining involved.
Sometimes, the gas has a lower percentage of methane, hance the overall density of the gas reduces, and more gas can be filled.
This 'mixed gas' has higher amounts of propane than usual.
Nothing to worry opther than the lower fuel economy.
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Old 15th June 2015, 10:48   #19
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Re: Why do pumps mix LPG with CNG occasionally?

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Originally Posted by HimuraKenshin View Post
This 'mixed gas' has higher amounts of propane than usual.
Nothing to worry opther than the lower fuel economy.
Thanks. I have been wondering for quite a while now. Almost all the pumps across Mumbai are having rich gas (mixed gas).
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Old 22nd July 2015, 18:06   #20
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Re: Why do pumps mix LPG with CNG occasionally?

Had written to Mahanagar Gas in Mumbai and got the below reply as some of you have mentioned. In case you want to contact Mr. Tiwari, PM me for the phone number or e-mail id
-----------------------------------------------------

Dear Mr. Prasad,

Greetings from Mahanagar Gas Ltd. (MGL).
As far as your query pertaining to mixing of gas is concerned; we would like to clarify this to you that adulteration in the CNG supplied at our out lets is not possible at all.
We would like to also inform you that CNG majorly comprises Methane (90-95%) and rest are higher carbon atom molecule gases like (ethane /iso propane etc) . But some times we receive Natural Gas in network where in the percentage of Methane is in the range of 85-88% and proportion of high density gas is more (rich gas) which relatively increases KGs intake in CNG cylinders.
You are requested to contact the undersigned during office hours for further details on the same.

Thanks and Regards,
Navneet Tiwari
Dy. Manager-CNG Marketing
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