Studies of Calorific Value Analysis

Study of Calorific Value Analysis

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Presented by CKIC-Damon Zhu

6th CKIC Overseas Training

Seminar Changsha, China

Catalogue

Basic Theory of Calorific Value 1

Requirements and Procedures 2

Comparison and Application 4

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Notes and Maintenance 3

What is Calorific Value?

The heat produced by combustion of a unit quantity of a substance (usually a fuel or food) under specified conditions, short for CV.

Gross Calorific Value (GCV)

Net Calorific Value (NCV)

The heat produced by complete combustion of a substance at constant volume, all water formed to liquid.

The heat produced by combustion of a substance at constant pressure, all water formed as vapor.

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Basic Theory

Importance of CV

The Calorific Value is a crucial characteristic for each substance Can be used for payment purpose of fuels. e.g. coal, coke,

biomass…

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Basic Theory

$/ton

Calorific Value decides Price.

Higher calorific value, higher price

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Importance of CV Basic Theory

2000ton

$10000 loss

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Importance of CV Basic Theory

How to test Calorific Value?

Calorimeter- a device used for measuring calorific value, it includes, ①oxygen bomb ②a bucket ③water and stirrer ④ temperature measuring device ⑤ ignition device ⑥a jacket.

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Basic Theory

Q=[E(△t+C)-q]/m

△t: Temperature rise

C: Cooling coefficient

q: Heat of ignition wire and additive

m: Mass of standard materials

E: Heat capacity

The energy required to raise the temperature of the calorimeter

one arbitrary unit, J/K

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Basic Theory

Test area: • Free from drafts, direct sunlight, radiation sources. • Room temperature and humidity controlled desirably.

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Requirement

Environment for CV analysis

Combustion Bomb:

• Not effected by combustion or products formed to avoid introducing heat input. • Designed to completely recover all liquid combustion products by washing inner surface. • No gas leakage. • Withstand 20 MPa hydrostatic pressure.

Balance

• Nearest to 0.0001g. • Weekly checked for accuracy

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Apparatus Requirement

Calorimeter vessel:

Jacket:

• Tarnish-resistant coating, outer surface highly polished. • A stirrer provided for mixing water. But the stirrer should not raise calorimeter 0.01℃ in 10minutes’ mixing.

• Inner perimeter maintained at constant temperature±0.1 ℃ • Inner surface not be >10mm from sides, top and bottom of calorimeter vessel.

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Apparatus Requirement

Thermometer:

• Platinum resistance or thermistor thermometer. • Capable of measuring to the nearest to 0.0001 ℃.

Sample Holder:

• An open crucible of platinum, quartz or base metal alloy. • Heat treat base metal crucibles for a minimum of 4 h at 500 ℃ to ensure the crucible surface is completely oxidized.

Ignition Fuse and Circuit:

• 100-mm length, 0.16-mm diameter or smaller. • Nickel-chromium alloy, cotton thread, iron wire. • 6-30V alternating or direct current.

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Apparatus Requirement

Reagent water:

Benzoic acid:

Oxygen:

• Pellets made from benzoic acid from NIST, or calibrated against NIST standard material • Should be traceable to a recognized certificate value

• Made from liquid air, >99.5% purity, free of combustible matter. • Do not use the oxygen made by the electrolytic process

• Distilled water

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Reagents Requirement

5E-AC/PL 5E-C5500 5E-C5508

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Automatic Equipments

Equipment

Structure

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Equipment Standards ASTM D5865 ASTM D4809 ISO 1928 GB/T213 AS 1038.5

5E-C5500

Vessel

Bucket Jacket reservoir

Chiller

Jacket inlet pump

Bucket drain pump

Jacket inlet valve

Vessel inlet valve

Balance inlet valve

Vessel inlet pump

Water flow

Cover

- In accordance with ASTM D5865 (10 – 35) ℃ CKIC

Procedure

Step 1 • Preparation

Step2 • Analysis

Step 3 • Calculation

Preparation for CV analysis

• Weigh 0.8-1.2g. • Nearest to 0.0001g.

- In accordance with ASTM D5865 (10 – 35) ℃ CKIC

Procedure

Weigh the sample

Connect Ignition fuse

• Ignition fuse touches the sample, but not touch the crucible.

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Procedure

Preparation for CV analysis

- In accordance with ASTM D5865 (10 – 35) ℃

Assemble the bomb.

• Add 1.0ml water to bomb before assembly.

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Procedure

Preparation for CV analysis

- In accordance with ASTM D5865 (10 – 35) ℃

Charge oxygen

• Flow pressure 3.0Mpa ,keep pressure constant for oxygen charging

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Procedure

Preparation for CV analysis

- In accordance with ASTM D5865 (10 – 35) ℃

Procedure

Check the leakage, load the bomb

• If there is evidence of gas leakage, stop the process.

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Preparation for CV analysis

- In accordance with ASTM D5865 (10 – 35) ℃

Set the program and get start analysis

Water mass deviation ±0.5g of each test.

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Procedure

CV analysis

- In accordance with ASTM D5865 (10 – 35) ℃

Start stirring and observe temperature change

• Temperature stability 0.001℃/s before ignition

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Procedure

CV analysis

- In accordance with ASTM D5865 (10 – 35) ℃

ignition and analysis

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Procedure

CV analysis

Formula

Qvad(gross)=[ (tEe)-e1-e2-e3-e4]/m

Ee = heat capacity t = corrected temperature rise e1 = acid correction e2 = fuse correction

e3= sulfur correction e4 = combustion aid correction m = mass of sample

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Procedure Calculation

Calibration

Benzoic Acid

• 10 tests, RSD ≤ 0.17%

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Cal NO: 1 Bomb Vessel 1 (215) Cal NO: 2 Bomb Vessel 1 (215) Cal NO: 2 Bomb Vessel 1 (215)

Date Calibration: 07/02/14 Date Calibration: 15/03/14 Date Calibration: 30/04/14

Benzoic Calorific value: 26470 J/g (6,326 Kcal/kg) Benzoic Calorific value: 26470 J/g (6,326 Kcal/kg) Benzoic Calorific value: 26470 J/g (6,326 Kcal/kg)

Uncertainty:0.1% (K=2) Uncertainty:0.1% (K=2) Uncertainty:0.1% (K=2)

5E-C5500 5E-C5500 5E-C5500

NO of STD Heat capacity(J/c) Xi-Xbar (Xi-Xbar)2 NO of STD

Heat capacity(J/c) Xi-Xbar (Xi-Xbar)2 NO of STD Heat capacity(J/c) Xi-Xbar (Xi-Xbar)2

1 9957 -6.1 37.21 1 9978 -2.2 4.84 1 10013 4 16.00

2 9962 -1.1 1.21 2 9979 -1.2 1.44 2 10019 10 100.00

3 9960 -3.1 9.61 3 9989 8.8 77.44 3 10013 4 16.00

4 9964 0.9 0.81 4 9981 0.8 0.64 4 10009 0 0.00

5 9958 -5.1 26.01 5 9983 2.8 7.84 5 10004 -5 25.00

6 9962 -1.1 1.21 6 9985 4.8 23.04 6 10015 6 36.00

7 9966 2.9 8.41 7 9981 0.8 0.64 7 10005 -4 16.00

8 9961 -2.1 4.41 8 9975 -5.2 27.04 8 10006 -3 9.00

9 9971 7.9 62.41 9 9966 -14.2 201.64 9 10002 -7 49.00

10 9970 6.9 47.61 10 9985 4.8 23.04 10 10001 -8 64.00

Average 9963 Sum 198.90 Average 9980 Sum 367.60 Average 10009 Sum 331.00

SD 4.70 s2 22.10 SD 6.39 s2 40.84 SD 6.06 s2 36.78

%RSD 0.05 sd 4.70 %RSD 0.06 sd 6.39 %RSD 0.06 sd 6.06

%rsd 0.05 %rsd 0.06 %rsd 0.06

Cal NO: 1 Bomb Vessel 2 (644) Cal NO: 2 Bomb Vessel 2 (644) Cal NO: 2 Bomb Vessel 2 (644)

Date Calibration: 07/02/14 Date Calibration: 15/03/14 Date Calibration: 29/04/14

Benzoic Calorific value: 26470 J/g (6,326 Kcal/kg) Benzoic Calorific value: 26470 J/g (6,326 Kcal/kg) Benzoic Calorific value: 26470 J/g (6,326 Kcal/kg)

Uncertainty:0.1% (K=2) Uncertainty:0.1% (K=2) Uncertainty:0.1% (K=2)

5E-C5500 5E-C5500 5E-C5500

NO of STD Heat capacity(J/c) Xi-Xbar (Xi-Xbar)2 NO of STD

Heat capacity(J/c) Xi-Xbar (Xi-Xbar)2 NO of STD Heat capacity(J/c) Xi-Xbar (Xi-Xbar)2

1 9984 1 1 1 9976 -8 64.00 1 10018 10 100.00

2 9994 11 121 2 9990 6 36.00 2 10015 7 49.00

3 9979 -4 16 3 9982 -2 4.00 3 10006 -2 4.00

4 9977 -6 36 4 9984 0 0.00 4 9998 -10 100.00

5 9982 -1 1 5 9973 -11 121.00 5 10005 -3 9.00

6 9990 7 49 6 9993 9 81.00 6 10001 -7 49.00

7 9987 4 16 7 9991 7 49.00 7 10002 -6 36.00

8 9987 4 16 8 9981 -3 9.00 8 10013 5 25.00

9 9967 -16 256 9 9984 0 0.00 9 10005 -3 9.00

10 9982 -1 1 10 9988 4 16.00 10 10020 12 144.00

Average 9983 Sum 513.00 Average 9984 Sum 380.00 Average 10008 Sum 525.00

SD 7.55 s2 57.00 SD 6.49 s2 42.22 SD 7.63 s2 58.33

%RSD 0.08 sd 7.55 %RSD 0.07 sd 6.50 %RSD 0.08 sd 7.64

%rsd 0.08 %rsd 0.07 %rsd 0.08

Remark: ASTM-D5865-10a, the precision of ten acceptable calibration test runs shall have a Relative

Standard Deviation (%RSD) no greater than 0.17%

Overview for 5E-C5500 Automatic Calorimeter

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Calibration

Release the pressure

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Operation Notes

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• All parts of the bomb should be

rinsed

Rinse the bomb

Operation Notes

Check bomb before every analysis. Do not fire the bomb if there’s evidence of gas leakage.

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Operation Notes

Do not fire the bomb if it’s dropped or turned over after loading.

Do not extend any portion of body over calorimeter during ignition.

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Operation Notes

Maintenance

Do hydrostatic test for bomb, every 5000 analysis or 2 years.

Replace the water every 3 months, and recalibrate.

Do calibration whenever significant alteration made in the measurement system.

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Valves, gauges, gaskets should meet industry safety codes.

• Do not be stained with oil, grease or combustible.

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Maintenance

Main difference between ASTM, ISO, GB

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Comparison

Biomass or high volatile matter

①

② ③

④

• For biomass, or higher volatile matter sample, wrap with lens paper.

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Application

Oil or High CV Matter

①

② ③

④

• For oil or high CV matter, reduce the sample mass.

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Application

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