ChE 402: Chemical Engineering Laboratory-VExperiment No: 06

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(A) STANDARD TEST METHOD FOR CORROSIVENESS TO COPPER FROM PETROLEUM PRODUCTS BY COPPER STRIP TEST

(B) STANDARD TEST METHOD FOR GROSS CALORIFIC VALUE OF COAL AND COKE BY THE ADIABATIC BOMB CALORIMETER

Preparedby

Mir Hasib-Ul-LatifStudent number: 1002058

Level-4 Term-1Chemical Engineering Department

Bangladesh University of Engineering and Technology

Date of Performance: March 03, 2015 Group No: 05 (A2)Date of Submission: June 02, 2015 Partners’ Student number: 1002055 1002056 1002057 1002059 1002060

Summary

The objective of the Copper strip corrosion test is to know the process to determine the

degree of corrosion of copper from petroleum products by comparing with the American

Society of Testing and Materials (ASTM) Copper strip corrosion standards. In this

experiment diesel sample had been used as the petroleum product. It is important to know the

degree of corrosion of copper to handle petroleum products in copper vessels or conduits.

The copper strip found to be ‘slightly tarnished’ in contact with the sample diesel oil. The

objective of the bomb calorimeter experiment is to get acquainted with the process to

determine the calorific value of solid fuels such as coal, coke etc according to the ASTM

standard testing method. To know the calorific value of a fuel is very important to select the

appropriate fuel that should be used in a certain process. It would give the heat energy

evolved by combustion of each fuel and thus the amount, quality and economy of using a

specific solid fuel can be studied by this experiment. The gross calorific value of the sample

coal was found to be 6740 kcal/kg.

(A)STANDARD TEST METHOD FOR CORROSIVENESS TO COPPER FROM PETROLEUM PRODUCTS BY COPPER STRIP TEST

Definition

Corrosiveness: Corrosiveness refers to cause irreversible damage or destroy to a substance by another substance that has the power to contact.

Scope

This test method covers the detection of the corrosiveness to copper of aviation gasoline,

aviation turbine fuel, automotive gasoline, natural gasoline or other hydrocarbons having a

Reid vapor pressure no greater than 18 psi (124 kPa), cleaners (Stoddard) solvent, kerosine,

diesel fuel, distillate fuel oil, lubricating oil, and certain other petroleum products.

(Warning--Some products, particularly natural gasoline, may have a much higher vapor

pressure than would normally be characteristic of automotive or aviation gasolines. For this

reason, extreme caution must be exercised to ensure that the test bomb containing natural

gasoline or other products of high vapor pressure are not placed in the 100oC (212oF) bath.

Samples having Reid vapor pressures in excess of 18 psi (124 kPa) may develop sufficient

pressure at 100oC to cause rupture of the test bomb.

Significance

Crude petroleum contains sulfur compounds most of which are removed during refining. However, of the sulfur compounds remaining in the petroleum product, some can have a corroding action on various metals and this corrosivity is not necessarily related directly to the total sulfur content. The effect can vary according to the chemical types of sulfur compounds present. The copper strip corrosion test is designed to assess the relative degree of corrosivity of a petroleum product.

Apparatus

The apparatus used in the standard method of copper strip corrosion test are listed below:

Test tubes:

25 by 150 mm test tube is used in the standard test. It is capable of containing enough fuel

to make the copper strip completely submerged.

Constant temperature bath:

A bath capable of being maintained at a constant temperature (here 50±

1ºC) and having

suitable supports to hold the test tubes in a vertical position and immersed to a depth

about 100 mm. Either water, oil, or Aluminum block baths are suitable. The bath

temperature is maintained by an electric heating system inside.

Copper Strip Corrosion Test Bomb:

It is constructed of stainless steel according to the standard dimensions and capable of

withstanding a test a test pressure of 100psi.

Thermometers:

Normal thermometer cápable of measuring the temperature of constant temperature

bath.Thermomåters should be of total immersion type, for indicating ôhereñuéred test

temperatõre with smallest graduations of 1oC or less. No more than 25 mm of the mercury

thread should extend above the surface of the bath at the test temperature. The ASTM

12C or 1P 64C thermometer is suitable.

Polishing Vice:

It is used for holding the copper strip firmly without marring the edges while polishing.

Any convenient type of holder may be used provided that the strip is held tightly and that

the surface of the strip being polished is supported above the surface of the holder.

Viewing test tubes:

They are flat and convenient for protection-corroded strip for close inspection or storage.

Materials

Wash solvent :

Any volatile sulphur-free hydrocarbon solvent may be used provided that it shows no tarnish

at all when tested at 50°C (122°F). In our experiment Acetone had been used to wash the fresh

polished copper strip

Polishing material:

Silicon carbide or alumina grit paper of varying degrees of fineness including 65- m (240-

grit) silicon carbide paper or cloth: also a supply of 105 m (150 mesh) silicon carbide grain

and pharmaceutical grade absorbent cotton (cotton wool) can be used for this purpose.

Copper strips:

Strips of 12.5 mm wide, 1.5 to 3.0 mm thick, 75 mm long from smooth-surfaced, hard-

temper, Cold-finished copper of 99.9+ percent purity is required by standard method of

testing. Electrical bus bar stock is generally suitable. The strips may be used repeatedly but

should be discarded when the surfaces become deformed on handling.

Experimental Setup

Fig-6.A.1: Pressure vessel for copper strip corrosion test.

Procedure

Surface preparation: Surface blemishes from the sides of the strip is removed with

silicon carbide or alumna grit paper of such degrees of fineness as are need to

accomplish the desired results efficiently. All marks that may have been made by

other grades of paper used previously should be removed. The strip is immersed in

wash solvent from which it may be withdrawn immediately for final polishing or in

which it may be stored for future use. As a practical manual procedure for surface

preparation a sheet of the paper on a flat surface is placed, it is moisten with kerosene

or wash solvent, and the strip is rubbed against the paper with a rotary motion,

protection the strip from contact with the fingers with an ash less filter paper.

Alternatively, the surface of the strip may be prepared by use of motor-driven

machines using appropriate grades of dry paper or cloth.

Final polishing: After removing the strip from the wash solvent, holding it in the

fingers protected with ash less filter paper, first the ends and then the sides are

polished with the 105- m (150- mesh) silicon carbide grains picked up from a clean

glass plate with a pad of cotton (cotton wool) moistened with a drop of wash solvent.

It is wiped vigorously with fresh pads of cotton and should be handled only with

stainless forceps and should not be touched with fingers.

Immersing the copper strip in diesel oil:The copper strip is then immersed in the

test tube containing diesel oil and the test tube is set inside the test bomb by

immersing it in a water bath of (50 ± 1oC) in such a way so that the test tube is held

firmly and in a vertical position.

The copper strip removed:Then the test bomb is opened, the copper strip is

withdrawn from the test tube. It has to be handled very carefully so that any type of

marking or staining can be avoided.

Strip Examination:After withdrawing the copper strip gently with forceps it is

immersed in the wash solvent and then dried with filter paper by blotting only. Then it

is observed by comparison for the copper strip corrosion stándard to measure ôhe

degree of corrosion if taken place. The ãoðper strip and the standard strip have to be

held in 45o angle tïwards the light.

ASTM Copper strip corrosion standard:

The American Society of Testing and Materials provided the followingclassification for the

Copper strip corrosion test (ASTM D 130-94)

Table-6.A.1: ASTM Copper strip classifications

Classificatio

nDesignation Description

Freshly

polished strip--

1aSlight Tarnish

Light orange, almost the same as a

freshly polished strip

1b Dark orange

2a

Moderate

Tarnish

Claret red

2b Lavender

2cMulti-colored with lavender blue or

silver, or both overlaid on claret

2d Red Silvery

2e Brassy or gold

3a

Dark Tarnish

Magenta overcast on brassy strip

3bMulti-coloured with red and green

showing (peacock), but no grey

4a

Corrosion

Transparent black, dark grey or

brown with peacock green barely

showing

4b Graphite or lusterless black

4c Glossy or jet black

Observed Data

Description of corroded copper strip : Dark orange

Designation : Slight tarnish

Classification : 1b

Results and Discussion

The copper strip found to be ‘slightly tarnished’ in contact with the sample diesel oil, which

refers to that the sample diesel oil causes a little change by reacting with Copper.

This slight tarnish of a copper strip represents a very minute amount of ‘S’ present in the

sample that does not cause corrosion to the copper strip. And this copper strip can be reused

and also can be used as a container or conduit of such diesel oil or petroleum products

possessing similar properties. From the ‘Moderate Tarnish’ classification range the sample oil

becomes hazardous for the metallic copper vessels, and should not be used as a container or

conduit for long term. If it goes to the Corrosion range of classification i.e. black or grey

layer is found on the copper strip then the oil is extremely hazardous for copper vessels and

some other metallic or plastic containers should be tested for using as the container or a

conduit. So this test proves to be very useful for selecting a copper made vessel or tube to

contain different petroleum products.

The contaminants in the oil enhance the corrosion tendencies to metal. The corrosiveness of

the oils like aviation gasoline, automatic gasoline, tractor oil, kerosene, diesel, lubricating oil

etc. to copper can be accomplished by copper corrosion test. Corrosiveness must be avoided

for safe and economical operation. While selecting materials for the construction of various

equipments the important consideration is the prevention of corrosion. And so a material

should be chosen which remains unaffected by the fuel used.

The Copper strip has to be well prepared according to the method and shouldn’t have any

blemishes or stain on it. The test should be repeated if the sharp edges along the flat faces of

the strip appear to be in a classification higher than the greater portion of the strip.

When a strip is in the obvious transition state between that indicated by any two adjacent

standard strips, the sample is taken to be in the more tarnished classification.

The limitation of this experiment that the test result is observed compared with naked eyes

and can be erroneous and the result can vary for different observers. It is quite difficult to

distinguish between the colors in the slight and moderate tarnish ranges. So the test should be

run several times to be assured of the final result.

(B)STANDARD TEST METHOD FOR GROSS CALORIFIC VALUE OF COAL AND COKE BY THE ADIABATIC BOMB CALORIMETER

Definition

Calorific Value:

The heat produced by combustion of a unit quantity of a substance under specified

conditions. In the ASTM standard test method it is express in Btu/lb units. Calorific value

may also be expressed in (cal/g) or in SI units (J/g) when required.

Gross calorific value:

Gross heat of combustion at constant volume, Qv (gross)

Energy Equivalent/heat capacity/water equivalent:

The energy required to raise the temperature of the calorimeter one arbitrary unit. This is the

quantity that when multiplied by the temperature rise , then adjusted for extraneous heat

effects and divided by the mass of the sample gives the gross calorific value.

So, Gross Calorific value of Coal, Hc =

wΔT−e1−e2−e3

m

Where,

w = energy equivalent of the sample, cal/oC

ΔT= temperature rise in the calorimeter, oC

e1, e2 ,e3 = Thermochemical energy corrections for the test

m= mass of sample(coal) taken , g

For calculation of the correct gross calorific value, proper allowances for heat contributed by

other processes and thermochemical corrections should be made. The thermochemical

corrections related to this experiment are discussed below shortly.

Scope

This test method covers the determination of the gross calorific value of coal and coke

by the adiabatic bomb calorimeter

The values stated in SI units and British thermal units are to be regarded as the

standárä

This standard does not purport to address the safety concerns éf any, associated with

its use. It is the responsibilitù of the user of this standard to establish appropriate

safety and healtè practices and determine the applicability and regulatoòylimitátions

prior to use

All accountability and quality control aspecôs of ASTM Guide D 4621 apply to this

standard

Significance

The gross calorific value is used to compute the total calorific content of the quantity of coal

represented by the sample for payment purposes, provided the buyer and the seller mutually

agree upon this. It is also used in computing the calorific value versus sulfur contentto

determine if the coal meets regulatory requirements for industrial fuels. It can also be used for

evaluating the effectiveness of beneficiation processes or for research purposes.

Apparatus

Combustion Bomb: It should be constructed of materials that are not affected by the

combustion process or products sufficiently to introduce measurable heat input or

alteration of end products. There must be no gas leakage during the test. The bomb

must be capable of withstanding a hydrostatic pressure test of 20 MPa at room

temperature.

Calorimeter vessel:It should be made of metal with a tarnish resistant coating, and

with all outer surface highly polished. Its size shall be such that the bomb will be

completely immersed in water when the calorimeter is assembled. It has an electric

stirring system at a uniform rate but minimum heat input.

Jacket: There is a double-walled, water filled jacket fully enclosing the calorimeter.

Thermometers: used to measure temperature in the calorimeter and jacket. Here a

‘liquid-in glass’ type thermometer. ASTM standard thermometers 56C,56F,116C or

117F types can be used.

Thermometeraccessories: A magnifier is used for reading the thermometer to one

tenth of the smallest scale division.

Sample holder: It is an open crucible of platinum, quartz or acceptable base-metal

alloy.

Ignition wire

Ignition circuit: used for ignition purpose provides 6 to 16 V alternating or direct

current to the ignition wire. A pilot light is required in the circuit to indicate the

current is moving.

Experimental Setup

Fig-6.B.1: Schematic diagram of standard test method for gross calorific value of coal and coke by the adiabatic bomb calorimeter.

Procedure

The bomb is rinsed, inverted to drain and left to dry

A measured length of ignition wire is connected to the terminals, with enough slack to

allow the ignition wire to maintain contact with sample.

The bomb is assembled and O2 is charged at a pressure of 32 atm.

The calorimeter is filled with measured quantity of water(2000 g)adjusted from 1.0 to

2.0 oC below from room temperature.

The assembled bomb is placed in the calorimeter vessel. It is checked that no O2

bubbles are leaking from the bomb. The calorimeter vessel is then placed inside the

water jacket. Then the electrodes are connected. The stirrer, thermometer and cover of

the vessel are placed in definite positions. The stirrer is started then

The initial temperature reading just before igniting the wire is taken.

When 3 consecutive readings became same within one-tenth of smallest thermometer

subdivisions then it can be assumed that the temperature has risen to its final

equilibrium value and that reading is taken.

The cover is opened then, the bomb is removed and pressure is released. The interior

of the bomb is washed with distilled water containing titration indicator.

The combined pieces of unburned ignition wire are measured and subtracted drom the

original length.

Observed Data

Weight of sample ( coke+coal) = 1.2622 g

Initial temperature = 24.89oC

Final temperature = 28.44oC

Calculated Data

Temperature difference = 3.55oC

Calorific value= 6740 kcal/kg

Sample Calculation

Temperature difference = (28.44-24.89) oC

= 3.55oC

Calorific value = (2405 × 3.55 -30) / 1.2622

= 6740 kcal/kg

Results and Discussion

The gross calorific value of the sample coal was found to be 6740 kcal/kg.

The gross calorific value of a solid fuel is a very important characteristic property of any

petroleum product or fuel as this value determines the quality or grade of the fuel. The higher

the calorific value, the better the quality or grade of the fuel as the calorific value refers to the

heat content of the fuel. And by burning a fuel through combustion reaction, heat energy is

evolved and transformed to many other useful forms.

So for selection of solid fuel when designing equipments or a plant, determination of its

calorific value is necessary to find out that whether it can serve the purpose for that definite

process and also proves to be an efficient and economic one.

Compared to the literature gross calorific value for general Anthracite coal which is

approximately 8600 kcal/kg, the calculated value for the given sample was 6814.26 kcal/kg

varied quite a bit, may be of composition difference and due to heat loss which are neglected

during the calculation.

According to the ASTM standard testing method all the apparatus handling and procedure

steps should have been maintained very strictly. It was required according to the calculation

steps that the calorimeter vessel and the test bomb are adiabatic fully, but it is not possible, a

little amount of heat loss cannot be prevented.

While ignition of the wire , the wire should be in definite contact with the sample fuel,

otherwise the circuit would not be closed, and the pilot light would show that no current is

passing through thus no ignition occurring. In our experiment we had to fix the wire 2 times

to ignite it properly.

While charging pressurized O2 gas in the bomb for combustion reaction, the supply rate

should be a uniform one and. The gas had to be admitted into the bomb so as not to blow

powdered material from the sample holder. If the pressure exceeds the specified pressure,

then the combustion reaction should not be continued anymore.

While handling the O2 cylinder and other pressurized vessels and some safety measures had

to be taken, and the vessels should contain some safety valve or rupture discs.