gfe 03 2013 jzhan qin

8/11/2019 Gfe 03 2013 JZhan Qin

http://slidepdf.com/reader/full/gfe-03-2013-jzhan-qin 1/5

M o r e i n f o r m

a t i o n :

w w w . g a s - f o r - e n e r g y . c o m

26 gas for energy Issue 3/2013

REPORTS Gas quality

Natural gas interchangeabilityin China: some experimental

researchby Yangjun Zhang and Chaokui Qin

Because of the difference between gas appliances in current China market and those research targets many

years ago, the well-established index- and diagram-based methods to predict interchangeability cannot be

taken as applicable to natural gases from different sources. 9 cookers and 6 water heaters were sampled and

tested to evaluate response to varying constituents. Some efficiency and CO emission changes were observed.

Results suggested further theoretical analysis and criterion be required to quantitatively define gas

interchangeability.

1. INTRODUCTION

Natural gas industry in China witnessed unprecedent-

edly rapid development in past 15 years. By the end of

2011 overall natural gas consumption increased to 108

billion cubic meters (BCM) annually from 24.5 BCM in

2000 [1]. The large-scale development of gas industry in

China dated back to late 1990s when the first transmis-

sion gas pipeline was put into operation in 1997, carry-

ing 3.6 BCM from Shanxi to Beijing each year. In 2004 a

3900km-long Western Gas (NO.1) pipeline was finished

and its annual transmission capacity was 12 BCM. The

second stage of Shanxi-Beijing pipeline was put into

operation with its capacity 12 BCM in 2005 [2]. Western

Gas (NO.2) pipeline construction was initiated in 2008

and finished in 2012, and its capacity was 30 BCM. Natu-

ral gas from Burma began to supply China in July, 2013.

It has been planned that natural gas from Russia can be

delivered to China by 2018. Table 1 and Figure 1 sum-

marized some distant pipelines in China.

Liquefied natural gas (LNG) began to play an impor-

tant role to satisfy rapidly-increasing demand in south-

B eg in ni ng Ye ar Fi ni sh Ye ar O ri gi n l oc at io n E nd l oc at io n L en gt h (k m) C ap ac it y

(BCM/year)

1 1992 1997 Shanxi Beijing 868 3.6

2 2000 2004 Xinjiang Shanghai 3900 12

3 2004 2005 Shanxi Beijing 918 12

4 2007 2009 Sichuan Shanghai 2206 12

52008 2012 Kazakhstan Shanghai/

Guangdong4895 30

6 2010 2013 Burma Yunnan/Guizhou 1727 12

7 2013 2018 Russia 38

Table 1. Some long-distance pipeline projects in China

Issue 3/2013 gas for energy 27

eastern China. In 2006 the first LNG terminal in Dapeng

(Guangdong) was put into operation, annual capacity

being 3.7 million tons (MMT). From then on several ter-

minals in Shanghai, Jiangsu, Dalian, Zhejiang were put

into operation (as shown in Figure 1), and the total

capacity increased to 24.2 MMT/a. It was expected that

10 terminals would be constructed along Chinese

coasts, and the total receiving capacity would climb up

to 50.9 MMT/a by 2017 [3].

The supply pattern of natural gas in China can be

summarized as “west-originated to east, north-originated

to south, sea-originated to land”. Accompanied with

gradual formation of long-distance pipelines and intro-

duction of LNG, more and more areas will be or have

been faced up with a fact that they are supplied with

gases from different sources. For example, there are 5 gas

sources in Shanghai and 6 gases in Guangdong. In Bei-

jing, there are also 4 sources.

The constituent differences of gases from different

sources may introduce an uncertainty related to perfor-

mance of appliances in end-users. There are as much as

80 gas sources in China (including some potential

sources), and their distribution in gas specification is illus-

trated in Figure 2 and Figure 3. The distribution of 80

gas sources is so wide, and LNG is generally richer thanpipeline natural gas (PNG) and offshore gas (OSG). CH4

vary from 72% to 100%, C2H6 and N2 can account up to

20%. In Chinese national standard GBT13611-2006 [4], it

was prescribed that Wobbe index of natural gas must fall

within 45.67 MJ/m3~54.78 MJ/m3. But no specific limit

with regard to constituent variation was strictly defined.

Figure 2. Properties of gas sources in China

Figure 3. The various gas constituents of gas sources in China

Figure 1. Distribution of gas pipeline in China

https://www.di-verlag.de/de/gas-for-energy/








































8/11/2019 Gfe 03 2013 JZhan Qin


M o r e i n f o r m

a t i o n :



present theories so as to justify what can be accepted

when interchanged. In 2010 BP published “Gas inter-

changeability and quality control” to include some experi-

ments incorporating pipeline gas and LNG.

Previous research revealed that all the interchangea-

bility results are based upon experiments according to

realistic gas constituents and gas appliances. Both final

judgment criteria as “Yes” or “No” and testing method

vary from a country to another. Unfortunately, in this field

no systematic research had been carried out and no reli-

able conclusion can be referred in China. On the other

hand, the supply amount of natural gas and appliance

increased dramatically in past decade.

Some experiments were performed in Tongji Univer-

sity from 2011 to measure performance response of gas

cookers and water heaters to different gases. Despite no

well-established conclusion has been arrived, the work

turned out to reflect present status of potential influence

resulting from varying constituents.

3. EXPERIMENT PROCEDURES

3.1 Technical approaches

The gas interchangeability was literally defined as theability of one gas to substitute another one on some

appliances without materially changing the operation of

appliances, including performance and emission, etc. For

a specific appliance, the standards to which it is subjected

always prescribe performance (including efficiency, emis-

sion, safety issues, etc.) in terms of minimum require-

ments. The testing procedures involved are also included.

For example, a gas cooker must have efficiency higher

than 50% (or 55%) and its CO emission (air-free) must be

lower than 500ppm according to relevant Chinese stand-

ards. The performance data should be measured when

fuelled by 2kPa of 12T-0 (Chinese classification number,

equivalent to G20). For a “qualified” cooker which has

efficiency 52% and CO 300ppm when fuelled by gas “A”,

its efficiency drops to 48% while CO emission remains

350ppm when fuelled by gas “B”. It is quite difficult toconclude if gas “B” can substitute gas “A”. In other words,

both objective and subjective issues are involved in the

field of interchangeability research. As shown in Figure 4,

the detailed parameters used to describe performance

also change from one kind of appliance to another. For

atmospheric appliances in China, publicly accepted issues

include lift, flash-back, yellow-tip, and CO emission but

no consideration was taken to efficiency across the world.

In this paper the sampled appliances were domestic

cookers and water heater incorporating atmospheric

combustion. Related standards include “GB 16410-2007

Domestic gas stove” [10] and “GB6932-2001 Domestic gas

instantaneous water heater” [11].

3.2 TEST RIG

3.2.1 Gas blending system

The test gases were supplied by gas-blending system

through which CH4, C2H6, C3H10, C4H10 and N2, CO2, were

blended to ensure exactly the same constituents as test

gases. Also the same Wobbe indexes and CP wereachieved. Gas-blending system including a 5m3 storage

tank was shown in Figure 5. The purities of individual

components involved were as follows: CH4 99.9%, C2H6

99.5%, C3H10 99.95%, C4H10 99.95%, N2 99.999%, CO2

99.6%. After all the individual components were fed into

the storage tank, the mixture remained 3-5 hours while

propeller was working. Then gas was sampled and ana-

lyzed by gas chromatography. When the constituents of

blended gas fell within allowable limitations compared

with test gases (listed in Table 2) [12], and the Wobbe

indexes, heating values, of blended gases differed not

much from those of test gases, the blended gas could be

regarded as identical to test gases.

Figure 4. The relationship between gas appliance test standard and

performance

Figure 5. Gas blending system

PNG

C

3 H 8

C

H

4

N 2

Pressure regulator

Gas meter

Storage tank

C

2 H 6

to Burners C

O

2

C

4 H 1 0


REPORTS Gas quality

Therefore natural gas interchangeability problem arises in

recent years. Both appliance manufacturers and local

delivery companies show their concern with the problem

if serious combustion-related difficulties may result and if

it is necessary to strict ly limit individual constituents.

2. HISTORY OF GAS INTERCHANGE-

ABILITY RESEARCH: A REVIEW

Technically natural gas interchangeability can be treated

as some kind of extension of gas interchangeability. A

brief review of interchangeability research will be helpful

as how to configure out theoretical and experimental

approach, so as to answer following questions: will con-

stituent difference of gases from different sources lead to

difficulties of various burners? Can appliance manufactur-

ers have enough capacity to deal with such differences?

In 1915, a large-scale survey in US was performed,

finally leading to four kinds of instability phenomena, viz.

lift, flash-back, yellow-tip and incomplete combustion.

On a diagram with primary-air and port intensity as coor-

dinates, four curves represent these limits of instabilities.

It was put forward the relationship between operation

point of a specific appliance and four curves can deter-

mine a margin with which the appliance would operatestably. In 1926 an Italian engineer Wobbe established an

index to evaluate influence of gas properties upon heat

input rating of a burner. In 1927 American Gas Association

(AGA) initiated a 6-year research project, finally leading to

“C index” approach. Shortly soon it was suggested that

flame speed should be included as an influencing factor

in 1934. In 1941 Knoy derived a mathematical formula to

predict interchangeability of liquefied petroleum gas

(LPG). In 1946 AGA laboratory (AGAL) published “Research

Bulletin 36” which put forward three indexes to quantita-

tively describe the degree of unstable phenomena

related with atmospheric combustion. But incomplete

combustion was not considered due to some technical

reasons. The gas burners used by AGAL were made of

cast-iron, with round-ports and ribbon-ports. In 1951

Weaver published a 6-index method to predict inter-changeability, after analyzing relationship between flame

speed and experimental results of AGAL. Basically Weaver

indexes represent the relative tendency of unstable com-

bustion when interchanged.

A research project presided by Delbourg (Gaz de

France, GDF) was initiated in 1950 and a diagram-based

method was established to predict interchangeability of

manufactured gas, natural gas-air mixture, propane-air

mixture, etc, in 1956. Combustion Potential (CP) was put

forward to represent influence of inner cone height and

its impact upon lift, flash-back and CO emission. On a

diagram with corrected Wobbe index and CP as inde-

pendent coordinate, Delbourg triangle defines an area

within which a specific burner can operate satisfactorily.

Two additional indexes were combined to judge if soot-

ing and yellow-tip would be encountered.

Another diagram-based method was put forward in

1956 by Gilbert and Prigg to consider constituent

changes resulting from manufactured gas process and

raw materials. On G-P diagram flame speed was abscissa

and Wobbe index was y-axis, both of which can be cal-

culated directly from gas constituent. Four groups of

gases, G4, G5, G6, and G7 were experimentally tested on

typical burners to establish limits of various gases. In

1964 Harris and Lovelace put forward a modified dia-

gram to take into account introduction of natural gas

into England and future potential of substitute natural

gas (SNG). Later in 1978 their approach was refined by

Dutton and allowable areas for long-term and short-

term operation were experimentally determined. Dut-

ton method is still adopted to decide whether a gas can

be introduced into networks in England.

In 1980s Harsha, P. T. [5] pointed out that applicability

of multi-index methods remained to be further clarified

since most of these approaches were based upon experi-

mental results from appliances popular at the time when

experiments were carried out. In 1990s Liss, W.E. [6] sug-

gested that interchangeability research should beemphasized again to evaluate the diversity of natural

gases including LNG and coal-based natural gas. Ted A.

Williams [7] systematically summarized interchangeabil-

ity researches available and concluded that the main tar-

get of research should be transferred from natural

gases—manufactured gas to constituent differences

between natural gases from different sources, such as

pipeline gas and LNG.

In 2003 National Petroleum Committee (NPC) pub-

lished a report “Balancing Natural Gas Policy-Fueling the

Demands of a Growing Economy” to call for necessity to

refresh interchangeability method so as to introduce non-

conventional gas. In Europe EASEE-gas published EASEE-

gas CBP 2005-001/02 to put forward Common Business

Practice in regard to gas specifications. Halchuk-Harrington

et al [8] recommended that the concept of “interchangea-bility” should be extended to include ALL appliances,

including gas-turbine, gas-engines. Furthermore it was

pointed out that most researches available were based

upon fuel gas rather than natural gas, targeting at estab-

lishing standards for peak-shaving plants and blending

plants. In addition natural gas considered in previous

research was apparently different from current gases, and

only a small portion of gases had similar constituents with

today’s natural gas and LNG. In 2009 Ennis C.J. et al [9] com-

pared gas constituents and interchangeability methods in

US with those in Europe. Test gases were compared to help

understand interchangeability approaches and their appli-

cability. It was concluded that it essential to re-evaluate









































8/11/2019 Gfe 03 2013 JZhan Qin


M o r e i n f o r m

a t i o n :



4. RESULTS AND ANALYSIS

4.1 Gas cooker

4.1.1 Heat input rating

Measured heat input rating of all sampled cookers under

different gases was shown in Figure 8(a). It can be foundthat heat input rating increases almost linearly with the

increasing Wobbe index for all cookers. This suggested

the heat input rating of cookers change consistently with

Wobbe index, and it also can be precisely predicted by

Wobbe index; on the other hand, it also means that

experiment results are quite accurate and reliable.

4.1.2 Thermal efficiency

Figure 8(b) shows the change of thermal efficiency

with varying gas constituents. Obviously the change of

thermal efficiency of gas cookers does not give any

regular pattern.

According to Ref [10], thermal efficiency of gas cooker

must be measured by use of both upper-limit pot and

lower-limit pot according to by heat input rating. Then the

thermal efficiency is calculated by interpolation of heat

intensity in terms of bottom area, viz. kJ/mm2. In fact such

procedure considers the flame and heat transfer in a more

objective way. However it tends to make the continuously

changing issue discrete. Secondly, the specific process ofcombustion and heat transfer were greatly influenced by

burner structure and those gas constituents which will

seriously affect flame characteristics, such as flame lumi-

nosity, height and speed. That is the reason why in most

published papers thermal efficiency was not taken as a

quantitative index to evaluate interchangeability in China.

It was prescribed in Ref [10] that thermal efficiency

must not be lower than 55% (for on-top cooker) or 50%

(for embedded cooker). From the experiment results it

can be concluded that with the change of gas constitu-

ents, thermal efficiency of all samples are not very satis-

factory. For all 9*10=90 operation points, only 75% (67

operation points) can be considered as “qualified” in

Figure 8. Measured performances of gas cookers when fuelled by different gases:

(a) heat input rating, (b)thermal efficiency, (c) CO emission, (d) NOx emission


REPORTS Gas quality

3.2.2 Test system

According to Ref[10] and Ref[11], a gas cooker test system

and a water heater test system, as shown in Figure 6 and

Figure 7 respectively, were set up to measure heat input

rating, thermal efficiency, flame shape and pollutant

emissions.

3.3 Test gas constituents and sampled gas

appliances

Three diffe rent types of natural gases, namely OSG,

PNG and LNG, will be introduced into Guangdong

networks successively from 2009 to 2020. Accord-

ingly 10 gases which have been presently available

and are planned were selected as test gases in this

paper. The detailed constituents of 10 test gases

were listed in Table 3, among which PNG1 has the

lowest Wobbe index and LNG5 has the highest

Wobbe index, and PNG3, LNG2 similar to 12T-0 (G20)

were in the middle of all gases.

9 sets of gas cookers covering 9 different brands

and three types of ports (namely, round, square, rib-

bon), and 6 sets of water heaters covering 3 differentbrands were selected as representatives of popular

burner structures in Guangdong. The popular struc-

ture of gas cookers in China markets includes injector

made of cast-iron, diffusion/distribution head made of

aluminum or cast-iron, together with burner head

made of casting copper alloys. Furthermore port inten-

sity of Chinese gas cooker was usually designed to be

7.0~9.0 W/mm2, much narrower than its US counter-

part in 1950s (4.5~16.8W/mm2) [5].

Component range

(mole %)

Reproducibility (%) Accuracy (%)

0~0.1 0.01 0.02

0.1~1.0 0.04 0.07

1.0~5.0 0.07 0.10

5.0~10 0.08 0.12

>10 0.20 0.30

Table 2. Accuracy and reproducibility of gas chromatography

Figure 6. Illustration of gas cooker test rig

Figure 7. Illustrative schematic of water heater testing rig

Gas storage tank gas meter

aluminum pot

flue gas measurement

thermometer

U-shape pressure gauge

gas cooker

thermometer

stirrer

sample ring

gas stoarge tank gas meter

water heater

flue gas measurementU-shape pressure gauge

Mole% CH4 C2H6 C3H8 C4H10 CO2 N2 HV (MJ/m3) WI (MJ/m3)

PNG1 96.00 0.70 0.20 0.10 2.30 0.70 37.04 48.3

PNG2 92.79 4.00 0.30 0.30 1.80 0.80 38.39 49.4

PNG3 98.90 0.20 0.22 0.20 0.00 0.46 37.70 50.7

OSG1 85.99 9.61 0.20 0.00 3.60 0.60 39.10 48.8

OSG2 84.40 4.70 2.40 5.20 0.90 2.40 43.84 52.4

LNG1 98.50 0.00 0.30 0.10 0.00 1.10 37.63 50.1

LNG2 97.00 1.90 0.30 0.10 0.00 0.70 38.30 50.6

LNG3 90.70 7.50 0.30 0.10 0.20 1.20 39.68 51.1

LNG4 89.40 6.00 3.20 1.10 0.00 0.30 42.12 52.9

LNG5 86.60 9.00 2.90 0.90 0.10 0.50 42.53 53.0

Table 3. Constituents and properties of natural gases for Guangdong test










































8/11/2019 Gfe 03 2013 JZhan Qin


M o r e i n f o r m

a t i o n :



REPORTS Gas quality

terms of efficiency, but there is no one gas cooker which

can give “qualified” thermal efficiency under all tested

gases. In other words, a lot of works remain to be finished

for the manufacturers before a cooker with enough flexi-

bility becomes available.

4.1.3 CO emission

From the very beginning of interchangeability CO emission

has been a significant issue to characterize appliance perfor-

mance. Usually there are clearly defined limits on CO emis-

sions for safety reasons. Figure 8(c)

illustrates CO emission of all samples

under different gases. The change of

CO emission with the gas constituent

doesn’t follow any regular pattern. A

slightly increasing trend of CO emission

with increasing Wobbe index was

observed, though the values of CO for

most samples fell below 500ppm. In Ref

[10] it is prescribed that CO emission (air-

free) must not be higher than 500ppm.

And it can be found that 6 sam-

ples can maintain lower CO emission

under all tested gases, accounting for

67%. For all 90 operation points, 78

operation points (about 87%) can be

considered as “qualified” in terms of

CO emission. So it can be concluded

that well-adjusted initial state of gas

cookers can be flexible enough not tomaterially increasing CO emission.

4.1.4 NOx emission

Figure 8(d) shows the NOx emission

of samples under different gases.

NOx emission of sampled cookers is

found to increase with increasing

Wobbe index, but NOx can be lower

than 90ppm under most test gases.

Anyway currently there is no manda-

tory requirement to specify the

allowable NOx emission.

4.1.5 Lift

For natural gas interchangeability

research, lift has always been a focus

issue due to the potential incomplete

combustion or even explosion haz-

ard. In Ref [10] lift is visually checked

immediately 15s after ignition. The

experiment results are shown in

Table 4. It can be found that lift tends

to happen to samples when fuelled

by lean gas such as PNG1, PNG2, OSG1

and LNG1. This can be attributed to

the smaller flame speed resulting

from higher inert contents.

C-A-1

PNG2 LNG1 LNG2

C-H-1

PNG1 PNG2 OSG1

C-D-1

PNG1 PNG2 PNG3

LNG1 LNG2 OSG1

C-I-1

PNG1 PNG2 PNG3

LNG1 OSG1

Table 4. Test results of lifting for gas cookers


4.2 Water heater

As illustrated in Figure 9(a) heat input rating of all sam-

pled water heaters were found to increase linearly with

Wobbe index increment. Compared with gas cookers,

the increasing degree of input rating is somewhat differ-

ent, though Wobbe index can also be used to predict

changing trend of heat input rating. Thermal efficiency measurement results were

shown in Figure 9(b), it can be found that variations of

efficiency remain within 4~5 percentage points. It was

specified that efficiency of third-/second-/first- class

water heater should not be lower than 84%, 88% and

96%, respectively. Two condensing water heaters

(W-A-1 and W-C-2) gave efficiency higher than 96%

and can be labeled as “qualified” under all 10 gases.

Efficiency of W-C-1 dropped below 88% under PNG1

and LNG1. The remaining 3 water heaters can give effi-

ciency higher than 88%.

As shown in Figure 9(c), only 5 measured points were

observed to give CO emission above 600ppm (allowable

highest concentration) which is specified by Ref [11]. All

the other 4 water heaters can be termed as “qualified”

under 10 gases, accounting for 67%.

NOx emission did not give any regular pattern with

change of gas constituents. Except for W-B-1 gave a

90ppm+ under LNG4 and LNG5, all the other water heat-

ers can keep an emission lower than 90ppm. An apparent

trend can be found that NOx emission increase withincreasing Wobbe index of gases.

5. CONCLUSIONS

Most interchangeability research available was per-

formed by means of experiments on appliances popular

at the time when the research was done. Because the

structure, material, designing parameters of burners in

current Chinese market differ much from those gas appli-

ances almost 50 years ago, it is quite doubtful whether

the well-established prediction methods (index- or dia-

gram-based) can be applicable to present Chinese gases

from different sources.

Figure 9. Measured performances of water heaters when fuelled by different gases:

(a) heat input rating, (b)thermal efficiency, (c) CO emission, (d) NOx emission










































8/11/2019 Gfe 03 2013 JZhan Qin


M o r e i n f o r m

a t i o n :



REPORTS Gas quality

9 gas cookers and 6 water heaters were experimen-

tally tested and heat input rating, thermal efficiency, CO

and NOx emission were measured when fuelled by 10

gases which have been/will be supplied in Guangdong.

The testing procedure and facilities involved strictly fol-

low related national standards. The conclusions can be

summarized as follows:

(1) The performance of domestic appliances (including

cookers and water heaters) are found to change with vari-

able gas constituents. None of the 9 cookers can give satis-

factory thermal efficiency under all 10 gases investigated.

1/3 of cookers were found to emit higher concentration of

CO and 44.4% of sampled cookers would have lift flame

under low Wobbe index gases. Only 3 cookers can keep

“qualified” in terms of both CO emission and lift, even if

thermal efficiency was not taken as a necessary measure-

ment index. 3 out of the 6 sampled water heaters can

maintain second-class efficiency under all 10 gases while

giving “qualified” CO emission. Half of sampled water heat-

ers would degrade with changing gas constituents.

(2) If a gas cooker was well-adjusted at the beginning

of measurement, CO and NOx emission would not change

materially. And most sampled appliances can tolerate the

variation range of constituents. Gas cookers tended to

decrease efficiency when gas constituents were changed,and more likely to become “unqualified”. For water heaters

tested, thermal efficiency could be maintained within a

range permitted by administrative requirement, and it

seemed no serious problem would occur.

The criterion as to decide whether a gas can be substi-

tuted by another one on a specific appliance depends on

both the standard to which the appliance is subjected and

the allowable margin, the latter of which is not fixed in terms

of quantitative indexes around the world. The work in this

paper can be considered as an initiating point to explore what

would happen to domestic appliances if the gas constituents

change to certain extent in China. Both theoretical analysis

and experiments are needed to further reveal applicable

index- or diagram-based method for Chinese gas industry.

REFERENCES

[1] BP Company. BP Statistical Review of World Energy

June 2012 [2012-06].

[2] Nobuyuki Higashi. Natural Gas in China Market evolu-

tion and strategy [2009-06].

[3] Energy Information Administration. China Energy

Data, Statistics and Analysis - Oil, Gas, Electricity, Coal

[2010-11].

[4] General Administration of Quality Supervision,

Inspection and Quarantine of the People's Republic

of China (AQSIQ). GB/T 13611-2006 Classification and

essential property of city gas. Beijing: China Standard

Press, 2006. (in Chinese)

[5] Harsha, P. T., Edelman, R. B., and France, D. H.: Catalogue

of Existing Interchangeability Prediction Methods.

Gas Research Institute, 1980.

[6] Liss, W. E., Thrasher, W. H.: Variability of Natural Gas

Composition In Select Major Metropolitan Areas Of

The United States, Final Report, GRI-92/0123. Gas

Research Institute, 1992.

[7] Williams, T.A.: AGA Interchange Background: Techni-

cal issues and research need in gas interchangeabil-

ity in the US [2006-06].

[8] Halchuk-Harrington, R. and Wilson, R.: AGA Bulletin 36

and Weaver Interchangeability Methods: Yesterday’s

Research and Today’s Challenges [2006-05].

[9] Ennis, C. J., Botros, K. K. and Engler, D.: On the Difference

between US Example Supply Gases, European Limit

Gases, and their Respective Interchangeability Indi-

ces [2009-05].



of China (AQSIQ).GB 16410-2007 Domestic gas stove.

Beijing: China Standard Press. 2007. (in Chinese)



of China (AQSIQ). GB 6932-2001 Domestic gas instan-

taneous water heater. Beijing: China Standard Press.2001. (in Chinese)



of China (AQSIQ). GBT13610-2003 Gas composition

analysis by gas chromatography. Beijing: China

Standard Press. 2003. (in Chinese)

AUTHORS

Yangjun Zhang, Ph.D. candidate

Gas Research Institute

China | Tongji University

Phone: +86 21 69583802

E-mail: [email protected]

Prof. Dr. Eng. Chaokui Qin

Gas Research Institute

China | Tongji University

Phone: +86 21 69583802

E-mail: [email protected]











































gfe 03 2013 jzhan qin

Documents