By MANJUNATH (R030307003) M-tech(GE)
Introduction to company Introduction Synopsis System descriptio description n
Metering for city gas distribution Classification Classi fication of flow measur measuring ing devices devices Meters used in Adani energy limited Description Descri ption of the mete meters rs Billing of domestic met meter er Selection of meter Meterr installation Mete Costing of domestic connection How a customer can steal unregistered gas Precautions to stop tampering of meter
Overview of the Adani groups
Adani Mundra Port Adani Real Estate Adani Energy Limited Adani Agro Adani Wilmar Limited Adani Power Adani Logistics Limited
Adani Energy Limited
Gas Distribution Adani group initiated Gas Distribution Business with a goal of providing safe, convenient, reliable and eco friendly fuel to.
Industrial Commercial domestic and transportation sectors
Fuel supply of AEL
PNG CNG
Places
Ahmedabad Vadodara
Network of AEL
< 110 KM of steel pipeline <1200 KM of PE line <45 CNG stations 12 DRS in city
Customers
< < < <
250 industries 2500 households 100 commercial units 45,000 vehicles
Gas supplier to AEL
Petronet LNG NIKO GSPL grid to AEL
Synopsis
This internship report deals with the metering for city gas distribution and its study Meters used in AEL Meter mechanism and installation pressure and temperature parameter which has to be considered while billing Increasing the meters efficiency
System description The system description involves the total arrangement or network in doing city gas distribution business.
City Gate Station Odorization District regulating station Industrial Metering and regulating station CNG station Pipeline Network
CGS
Gas Filtration skid Pressure reduction skid Flow metering skid
Metering of gas It refers to measuring gases based on the volumetric measurement, velocity, thermal and calorific method. AEL do volumetric and velocity based measurements of the gas supplied to the customer
inlet
outlet meter
Classification of metering devices 1. DP meters > Orifice meter > Venturi meter > Pitot tube meter 2. Positive displacement meters > Diaphragm meter > RPD meter > Piston type gas meter 3. Velocity meters > Turbine meters > Ultrasonic meter
Meters used in AEL
Senior Orifice meter Diaphragm meter RPD meter Turbine meter
Senior orifice meter:
This meter is used to measure the gas with high flow rate. Senior orifice has very less turndown ratio i.e of 10:1 Differential pressure cells: the DP transducer measures the differential pressures and converts it into electrical signals, as a input to flow computer. AEL use, DANIEL patented Orifice which gives DP values to the flow measuring machine BOSS. The patented equation is Qh = Fb*Fa*Fr*Y1*Fh*Fm*Fpv*Ftf*Fpb*Ftb*Fgr*√hw*Pf Fb = basic orifice factor Fa = orifice thermal expansion factor Fr = Reynolds number Ftb = temperature base factor Fg = specific gravity factor
Fpv = super compressibility factor Fh = gauge location factor Pf = flowing pressure hw = water head due to pressure
Diaphragm meter:
This is a positive displacement meter which measures the gas by holding and releasing mechanism of fixed volume . The flexible material used for this meter is a diaphragm made up of a synthetic fabric called reinforced nitro rubber Lever and linking mechanism are connected to the dial called index box which shows the amount of gas consumed by the customer. Following figure shows the internal structure of the meter
Reading the meter
The below figure registers cubic meters and here the first five digits give the quantity up as far as the decimal point. They are again surrounded by a thick black band. The last three digits represent the number of decimeters. The last digit representing 0.1dm3 per sub-division.
Meter index
Rangeability Of Diaphragm Meter:
It can be used to measure very less flow rate, which is desirable for the domest ic purpose. The rangeability is Qmin 0.016 m3/h, Qmax 2.5 m3/h to Qmax 65 m3/h Pressure should be max of 0.1bar. AEL use diaphragm meters from Actaris company.
Correction factor for diaphragm meter:
Volume and temperature Correctors will be fitted to all meters operating above 75 mbar and with a flow range of above 20 SCM/h. For flow below 20 SCM/H PD meters will be installed without volume and temperature Correctors. For these meters flow rate obtained is multiplied by correction factor given as
V1/V2= (P2*T1) / (T2*P1) V1 = std volume P1 = std pressure T1 = std temperature V2 = measured volume P2 = measured pressure T2 = measured temperature
Corrected flow = measured flow* correction factor. (standard condition scmh).
to calculate correction factors f or different mechanical meters(diaphragm)
Input base pressure P1 =
base temperature T1 =
1
Atm
1.01325
Bar
1013.25
Mbar
25 0.075
C Bar
operating pressure P2 =
75
Mbar
operating temperature T2 =
25
C
Output corection factor v1/v2 =
1.074019
for pressure in mbar
corection factor v1/v2 =
1.074019
for pressure in bar
Turbine meter:
Turbine gas meters are flow meters flow of gas turns a turbine wheel, and thus, the rotating speed of the turbine is proportional to the linear speed of the gas. The movement is mechanically transmitted to the totaliser through the magnetic coupling, which shows the reading.
For the flow calculation an electronic device is connected called EVC, electronic volume converter It gives readings in standard conditions
It got good turndown ration and accuracy i.e 50:1
Qmin = 10m3/h to Qmax = 400 m3/h
Internal arrangement of meter
EVC
Selection of meters:
Collection of data on load pattern
CRITERIA FOR SELECTION OF METER Following criteria shall be considered for the Best match, Contractual requirement Rangeability or Turndown ratio Accuracy required Suitability of meter with quality of gas available Pressure requirement Calibration & maintenance requirement Size & weight Installation and maintenance constraints Operability Cost Gas quality
Filtration Filtration at 50 microns should be fitted to all metering system operating at pressure above 75 millibar and 16SCM/hr
SN
Type of meter
Working pressure
Flow ra nge
Ba r
M3 / Hr
Type of customer
limita tion
recommended
1.
Dia phra gm Meter
Min
Ma x
Min
Ma x
0.0
0.2
.016
30
Domestic
Commercia l &
Bigger Sized,
Sma ll scale Industry with pressure requirement less tha n 75 mba r only
Expensive for high flow No Pressure & tempera ture compensation
2
Rota ry Positive
0.0
16
30
1000
Commercia l & Industria l
Requires: a) 50 m icron filtration Gas
Displacement Meter
Quality b) Lubrication Maintena nce
3
Orifice Meters
1.5
200
none
la rge .Industria l customers with a) In- accu racies b). Regular flow Turn down
calibration.
Ra tio within 3 :1
c) Long straight length of pipe
Bulk customers &
A) In- accu racies. b). Regular
With Single Transmitter
Orifice Meters
1.5
200
none
Transportation custody transfer calibration. With Double
meters
Transmitter 4
Turbine meters
c) Long straight length of pipe 2ba r
500
40000 Hi cost, gas qua lity.
5
Ultrasonic Meter
7ba r
99
1500
none
Bulk customers &
Hi cost, gas qua lity.
Meter installation
The installation starts from the piping from CGS to the customer The pipeline from CGS to DRS is of galvanized iron pipe or Corrugated stainless steel tubing (CSST)
At DRS pressure is reduced from 26 bar to 4bar
After this PE pipes are lined with service regulator up to the customer basement.
Again a galvanized iron pipe (20 t0 30mm) to the meter, with regulator and pressure gauge. Copper pipe (12mm) is line inside the kitchen up to burner or water heater. Meters should be installed at least 1m above the ground and should be inside the customer property Good ventilation should be provided, safety cover or a box with sealed . For the industries purpose we create a skid, which includes meter, regulator, pressure gauge and EVC
Costing of domestic connection: S.N
Item Description
Unit
Qty. Consider/Conn. Rate Rs./Unit
TOTAL Cost
1
G.I.Pipe 1/2" NB
Mtr
10
50
500
2
Copper pipe
Mtr
12
45
540
2
G.I fitting 1/2" NB
Nos
30% of pipe cost
-
150
22
Copper fitting cost
Nos
30% of pipe cost
3
RCC guard
Nos
1
100
100
4
1/2" Isolation Valve
Nos
1
125
125
5
Meter regulator
Nos
1
300
300
6
Domestic meter
Nos
1
1209
1209
7
Ball cock(gas tap 6.4mm)
Nos
1-consider one point 150
162
150
only 8
Rubber tube
Mtr
1
50
50
9
MDPE 20 mm dia
Mtr
5
20
100
10
MDPE 32mm dia
Mtr
12
25
300
10
MDPE fitting
Nos
2-coupler 20 dia & 1 -
590(500+90)
saddle 32X20
11
Labour cost of GI piping
Mtr
18
22
396
12
Labour cost of PE installation
Mtr
17
35
595
How a customer can steal unregistered gas:
The customer can steal extra gas or unregistered gas by adjusting or by changing the gear wheels behind the index, in case of diaphragm meters . For a particular customer company do some registration about the demand, based on which it decides to deliver fixed amount of gas with respect to pressure. A siple way a customer can take more gas by adjusting the pressure. Temperature can also play a vital role in stealing the gas. This can be done by decreasing the inlet line temperature. In EVC based meters in the battery or the solar panel got failed fo r a short time than at that instant, it stop recording the meter readings, as a result stops converting it into standard conditions. The customer used gas is not recorded in the EVC In case of the diaphragm. If the diaphragm of the meter is punctured, then there is a possibility of flowing extra gas to the customer
Precautions to stop tampering of the meters:
Always check for the meter sealing.
Meter reader should check the pressure settings and any variations in that.
And he should check for the temperature variations.
Check the battery and panel conditions of the EVC type meters.
Cross check the reading of EVC meter manually with the displayed one.
Check the set po ints of the EVC like super compressibility and base pressure and temperature conditions.
