CN104062317B - Result of combustion of tobacco thermal measurement method based on controlled equivalence ratio method and oxygen consumption principle - Google Patents

Abstract

The invention discloses a kind of result of combustion of tobacco thermal measurement method based on controlled equivalence ratio method and oxygen consumption principle, utilize controlled equivalence ratio method to realize the accurate regulation and control of air mass flow, tobacco supply and three important component of combustion of temperature, and then accurately control result of combustion of tobacco state; By the calculating to oxygen expenditure amount under stable state combustion state, and in conjunction with oxygen consumption principle, realize the Measurement accuracy of result of combustion of tobacco heat.

Description

Result of combustion of tobacco thermal measurement method based on controlled equivalence ratio method and oxygen consumption principle

Technical field:

The present invention relates to the result of combustion of tobacco thermal measurement method based on controlled equivalence ratio method and oxygen consumption principle, belong to calorimetry technical field.

Background technology:

Cigarette is a kind of special consumer goods that rely on burning to embody its quality. Result of combustion of tobacco heat is one of important parameter of result of combustion of tobacco characteristic, all closely related with flavor component formation and harmful substance release and cigarette ignition behavior etc. in tobacco aesthetic quality, flue gas.

At present, the measurement mechanism that can be used for material combustion heat mainly comprises tapered calorimeter and micro-combustion calorimeter. The design of taper calorimeter and micro-combustion calorimeter is all according to oxygen consumption principle, and while specifically referring to substance combustion, the oxygen of every consumption unit mass can produce substantially the same heat, and the oxygen consumption combustion heat of material is basic identical. Oxygen consumption principle is found in 1917 by Thornton. Huggett has carried out system-computed application oxygen consumption principle in 1980 to common combustible polymers and natural material, and the mean value that has obtained the oxygen consumption combustion heat is 13.1kJ/g, and the E value deviation of storeroom is 5%. It should be noted that, combustion heat release characteristics and material burning situation of living in is closely related, and for tobacco, the measurement of its combustion heat only just has more and is worth and practical significance under the condition that approaches cigarette burning environment. Present stage, great many of experiments and numerical simulation result are verified, the glow state of cigarette burning environment in the rich hydrogen of oxygen deprivation. Tapered calorimeter is to discharge for testing ad hoc rules sample heat under violent combustion case in the unlimited system of oxygen abundance, due to the particularity of tobacco sample physical behavior, is difficult to realize its accurate measurement to result of combustion of tobacco heat. Micro-combustion calorimeter is in the time that the combustion heat of measuring material discharges, be by minute quantity (general 4-5 milligram) sample after the abundant cracking of pyrolysis furnace, again cracked gas is placed in to combustion furnace burning, therefore its reflection is pyrolysis and the burning behavior of material under micro-scale, and repeatability is poor. Clearly, tapered calorimeter and micro-combustion calorimeter all cannot be accomplished to simulate cigarette combustion with meagre oxygen environment, are not suitable for the measurement of result of combustion of tobacco heat.

Standard ISO 19700 has proposed equivalence ratioConcept, core is to control the generation speed (v of fuel_Fuel) with the delivery rate (v of air_Air) ratio, shown in formula specific as follows,

WhenTime, represent that respectively material is in air abundance, stable state combustion when stoichiometric ratio (theoretical value) and under oxygen deprivation condition. Wherein,Physical meaning refer to the supply of air when each element in fuel fully burns. Therefore, based on oxygen consumption principle, utilize controlled equivalence ratio method just can Measurement accuracy tobacco the combustion heat under simulation cigarette burning situation.

Summary of the invention:

For overcoming the defect of prior art, the object of the present invention is to provide a kind of result of combustion of tobacco thermal measurement method based on controlled equivalence ratio method and oxygen consumption principle, to realize the tobacco Measurement accuracy that the combustion heat discharges under combustion with meagre oxygen state.

Technical solution problem of the present invention adopts following technical scheme:

Result of combustion of tobacco thermal measurement method based on controlled equivalence ratio method and oxygen consumption principle, it comprises the steps:

Step 1: calculate theoretical oxygen demand;

Tobacco sample, through elementary analysis, obtains C, H, and O, the percentage composition of S and N, the compound general formula of setting these five kinds of element compositions is C_xH_yO_zS_pN_q, in oxygen lucky clean-burning chemical formula suc as formula (1),

$C_x{H}_y{O}_z{S}_p{N}_q+{\mathrm{tO}}_2={\mathrm{xCO}}_2+\frac{y}{2}{H}_{2}O+{\mathrm{pSO}}_2+q{\mathrm{NO}}_2$ Formula (1)

In formula (1)The volume of required oxygen is when Elements C in 1g tobacco sample, H, O, N and the abundant combustion and pyrolysis of S:

Formula (2)

In formula (2), b is the mass fraction summation of C, H, O, S and five kinds of elements of N; M is C_xH_yO_zS_pN_qMolecular weight, i.e. M=12x+y+16z+32p+14q; R is ideal gas constant; P is the pressure of test gas; T is the temperature of test gas, due to C in living beings tobacco, H, O, five kinds of element mass fraction summations of S and N are up to more than 90%, the theoretical oxygen demand of its abundant combustion and pyrolysis can represent the clean-burning theoretical oxygen demand of tobacco, and when therefore this tobacco of 1g is fully burnt, theoretical air consumption is suc as formula (3)

Formula (3)

Therefore can obtain formula (4):

Formula (4)

Step 2: calculate actual air supply and tobacco sample supply;

Choose equivalence ratioAccording to equivalence ratio formula (5),

Formula (5)

Calculate the ratio of the actual fltting speed of tobacco sample and the feed speed of air, suc as formula (6),

Formula (6)

The delivery rate of setting fuel is (v_Fuel)_Actual, the actual flow of air is:

Formula (7)

In formula (7), fuel delivery rate advances speed v and tobacco sample quality W to calculate by load sampler length L, load sampler, specifically suc as formula (8),

Formula (8)

Formula (8) is based on following processing: Wg tobacco sample is wanted on the load sampler of uniform spreading Lcm in measurement mechanism;

Step 3: according to formula (7) and formula (8), set instrument parameter, after it is stable, accurately weigh pretreated Wg tobacco sample uniform spreading on Lcm load sampler, start experiment and measure in real time carrier of oxygen volume concentrations and temperature; Described pre-treatment step is carried out according to standard GB/T16447-2004;

Step 4: unit of account quality result of combustion of tobacco heat discharges;

(a) calculate result of combustion of tobacco HRR;

Choose carrier of oxygen volume concentrationsThe temporal evolution interval in ± 15% of fluctuating, now can be considered stable state, asks for the mean value of carrier of oxygen volume concentrations in this intervalAs formula (9),

$\stackrel{\‾}{f_{o_z}}=\frac{{\∫}_{t_1}^{t_2}{f}_{o_z}\mathrm{dt}}{t_2-t_1}$ Formula (9)

T in formula (9)₁、t₂Respectively starting point and the terminal between the steady-state zone of choosing;

In whole combustion process, be V for the one-level charge flow rate of the tobacco of burning₁l·min^-1, be V for the secondary charge flow rate of the cooling dilution of combustion product₂l·min^-1, specify V here₂≥10V₁Because oxygen content in one-level air inlet only has 21%, and the reduction of its volume number has made up the gas that tobacco cracking burning generates, therefore the twin-stage charge volume that burning causes changes very little, as calculated, rate of change is in ± 3%, and it can be ignored the impact of volume, that is to say, final gas gross is still (V₁+V₂)l·min^-1So the volume of unit interval internal consumption oxygen is suc as formula (10):

${\mathrm{\ΔV}}_{o_z}=(V_1+V_2)[{\left(f_{o_z}\right)}_0-\stackrel{\‾}{f_{o_z}}]$ Formula (10)

In formula (10)For the initial volume concentration of oxygen, for air, be 0.21;

Internal consumption oxygen quality is unit interval so,

$V_{o_2}=\frac{\mathrm{P\Δ}{V}_{o_2}{M}_{o_2}}{\mathrm{RT}}$ Formula (11)

In formula (11), P is ambient atmosphere pressure; T is the temperature of gas;It is oxygen molecule amount;

Result of combustion of tobacco HRR is,

$H_R=13.1\×v_{o_2}$ Formula (12)

(b) calculate the hot burst size of 1g result of combustion of tobacco

According to formula (8) and formula (12), calculate the hot burst size of 1g result of combustion of tobacco suc as formula (13),

Formula (13).

Compared with the prior art, beneficial effect of the present invention is embodied in:

Compared to existing technology, the present invention utilizes controlled equivalence ratio method to solve the problem that current combustion thermal measurement method is difficult to regulate and control result of combustion of tobacco environment, and can quantitatively calculate the hot burst size of result of combustion of tobacco under each combustion with meagre oxygen state in conjunction with oxygen consumption principle, for the accurate measurement of result of combustion of tobacco heat provides a feasible scheme.

Brief description of the drawings:

Fig. 1 is a kind of measurement mechanism schematic diagram of realizing result of combustion of tobacco heat release measuring method of the present invention.

Fig. 2 is that tobacco leaf A exists, O when 800 DEG C of burnings₂Concentration changes with time curve.

Fig. 3 is that tobacco leaf A exists, O when 800 DEG C of burnings₂Concentration changes with time curve.

Fig. 4 is that tobacco leaf A exists, O when 900 DEG C of burnings₂Concentration changes with time curve.

Fig. 5 is that tobacco leaf A exists, O when 700 DEG C of burnings₂Concentration changes with time curve.

Number in the figure: 1 one-level air inlet, 2 stepper motors, 3 quartz ampoules, 4 quartz boats, 5 tobacco samples, 6 rotary heating furnaces, 7 cooling and mixing casees, 8 secondary air inlets, 9 exhaust outlets, 10 filters, 11 paramagnetism oxygen analysers, 12 computers.

Below pass through detailed description of the invention, and the invention will be further described by reference to the accompanying drawings.

Detailed description of the invention:

Can realize a certain measurement mechanism of measuring method of the present invention as shown in Figure 1, it comprises:

There is the rotary heating furnace 6 of controller, one end that quartz ampoule 3 is located in rotary heating furnace is fire end, the other end is non-fire end, be provided with seal at described non-fire end, quartz boat 4 is located in described quartz ampoule and by outside stepper motor 2 and is promoted in quartz ampoule, at the uniform velocity to move, and is provided with two through holes for the supply air line path of one-level air inlet 1 and the transmission path of stepper motor 2 on described seal;

The outlet side of described rotary heating furnace 6 connects cooling and mixing case 8, is connected with exhaust outlet 9 and secondary air inlet 8 pipelines on described cooling and mixing case;

Paramagnetism oxygen analyser 11 is communicated with described cooling and mixing case by pipeline, and on connecting pipeline, is provided with filter 10, and described paramagnetism oxygen analyser 11 connects computer 12.

The pipeline of described one-level air inlet 1 is provided with one-level charge flow rate meter, and the pipeline of secondary air inlet 8 is provided with secondary charge flow rate meter.

Can adopt said apparatus to carry out result of combustion of tobacco thermal measurement based on controlled equivalence ratio method and oxygen consumption principle, embodiment is as follows:

Embodiment 1: the present embodiment is to the tobacco leaf A measurement that the combustion heat discharges in the time that 800 DEG C, equivalence ratio are 1 burning.

Tobacco leaf A is the cloud and mist 87C that Pu'er, Yunnan in 2011 produces₂F tobacco sample, obtains its carbon, hydrogen, oxygen, nitrogen, element sulphur content through elementary analysis and is respectively 43.24%, 6.29%, 42.98%, 1.93,0.77%. Setting the compound general formula that these five kinds of elements form is C_xH_yO_zS_pN_q, in conjunction with results of elemental analyses, can be reduced to C_3.6H_6.29O_2.69N_0.14S_0.02, its clean-burning chemical formula in oxygen is as follows,

C_3.6H_6.29O_2.69N_0.14S_0.02+3.9875O₂→3.6CO₂+3.145H₂O+0.02SO₂+0.14NO₂

(T=25 DEG C, P=1atm) at normal temperatures and pressures, in 1g tobacco sample, Elements C, H, O, N and the S requisite oxygen gas volume that fully burns is:

Because the percentage composition summation of C, H, O, N and S is up to 95.21%, the theoretical oxygen demand of its abundant combustion and pyrolysis can represent the theoretical oxygen demand of the abundant combustion and pyrolysis of tobacco substantially, and therefore theoretical air consumption is when the abundant combustion and pyrolysis of this tobacco of 1g:

Therefore there is following formula:

Choose equivalence ratioCan obtain

When on the quartz boat at 70cm by 17.5g tobacco sample uniform spreading, quartz boat fltting speed is 6cm/min, and tobacco feed speed is:

Air actual flow is:

According to formula result of calculation, be 6cm/min by the propelling rate setting of stepper motor, furnace temp is set as 800 DEG C of one-level charge flow rates and is set as 6.98L/min, secondary charge flow rate is set as 43.12L/min, after stable, accurately weigh 17.5g tobacco sample uniform spreading on 70cm quartz boat, start experiment and measure in real time carrier of oxygen volume concentrations. Can find out that according to Fig. 2 oxygen concentration fluctuates between 500～900s less, carrier of oxygen volume concentrations in this interval is added and after be averaged and obtain mean volume fraction and be:

$\stackrel{\‾}{f_{o_z}}=\frac{{\∫}_{t_1}^{t_2}{f}_{o_z}\mathrm{dt}}{t_2-t_1}=\frac{{\∫}_{500}^{900}{f}_{o_z}\mathrm{dt}}{900-500}=18.566\%$

Therefore the volume of the oxygen of 1min internal consumption is:

${\mathrm{\ΔV}}_{o_z}=(V_1+V_2)[{\left(f_{o_z}\right)}_0-\stackrel{\‾}{f_{o_z}}]=50L\·{\min }^{-1}\×(0.21-0.18566)=1.217L\·{\min }^{-1}$

Within 1 minute, internal consumption oxygen quality is:

$V_{o_2}=\frac{\mathrm{P\Δ}{V}_{o_2}{M}_{o_2}}{\mathrm{RT}}=1.559g/\min$

Wherein P is an atmospheric pressure,For oxygen molecule amount, temperature when T is gas stable state, test result is 25.1 DEG C;

So 1g tobacco leaf A is at 800 DEG C and equivalence ratioTime the combustion heat be released to:

Embodiment 2: the present embodiment is to the tobacco leaf A measurement that the combustion heat discharges in the time that 800 DEG C, equivalence ratio are 2.5 burning.

The abundant Theory of Combustion specific air consumption of 1g tobacco sample A refers in embodiment 1 and calculates. Choose equivalence ratioCan obtain

When on the quartz boat at 70cm by 21.875g tobacco sample uniform spreading, quartz boat fltting speed is 6cm/min, and tobacco feed speed is:

Air actual flow is:

According to formula result of calculation, be 6cm/min by the propelling rate setting of stepper motor, furnace temp is set as 800 DEG C of one-level charge flow rates and is set as 3.49L/min, secondary charge flow rate is set as 46.51L/min, after stable, accurately weigh 21.875g tobacco sample uniform spreading on 70cm quartz boat, start experiment and measure in real time carrier of oxygen volume concentrations. Can find out that according to Fig. 3 oxygen concentration fluctuates between 600～1000s less, carrier of oxygen volume concentrations in this interval is added and after be averaged and obtain mean volume fraction and be:

$\stackrel{\‾}{f_{o_z}}=\frac{{\∫}_{t_1}^{t_2}{f}_{o_z}\mathrm{dt}}{t_2-t_1}=\frac{{\∫}_{600}^{1000}{f}_{o_z}\mathrm{dt}}{1000-600}=19.35\%$

Therefore the volume of the oxygen of 1min internal consumption is:

${\mathrm{\ΔV}}_{o_z}=(V_1+V_2)[{\left(f_{o_z}\right)}_0-\stackrel{\‾}{f_{o_z}}]=50L\·{\min }^{-1}\×(0.21-0.1935)=0.825L\·{\min }^{-1}$

The quality of 1 minute internal consumption is:

$V_{o_2}=\frac{\mathrm{P\Δ}{V}_{o_2}{M}_{o_2}}{\mathrm{RT}}=1.046g\·{\min }^{-1}$

Wherein P is an atmospheric pressure,For oxygen molecule amount, temperature when T is gas stable state, test result is 25.0 DEG C;

So 1g tobacco leaf A is at 800 DEG C and equivalence ratioTime the combustion heat be released to:

Embodiment 3: the present embodiment is to the tobacco leaf A measurement that the combustion heat discharges in the time that 900 DEG C, equivalence ratio are 1.5 burning.

The abundant Theory of Combustion specific air consumption of 1g tobacco sample A refers in embodiment 1 and calculates. Choose equivalence ratioCan obtain

When on the quartz boat at 70cm by 17.5g tobacco sample uniform spreading, quartz boat fltting speed is 6cm/min, and tobacco feed speed is:

Air actual flow is:

According to formula result of calculation, be 6cm/min by the propelling rate setting of stepper motor, furnace temp is set as 900 DEG C of one-level charge flow rates and is set as 4.65L/min, secondary charge flow rate is set as 45.35L/min, after stable, accurately weigh 17.5g tobacco sample uniform spreading on 70cm quartz boat, start experiment and measure in real time carrier of oxygen volume concentrations. Can find out that according to Fig. 4 oxygen concentration fluctuates between 600～1100s less, carrier of oxygen volume concentrations in this interval is added and after be averaged and obtain mean volume fraction and be:

$\stackrel{\‾}{f_{o_z}}=\frac{{\∫}_{t_1}^{t_2}{f}_{o_z}\mathrm{dt}}{t_2-t_1}=\frac{{\∫}_{600}^{1100}{f}_{o_z}\mathrm{dt}}{1100-600}=18.89\%$

Therefore the volume of the oxygen of 1min internal consumption is:

${\mathrm{\ΔV}}_{o_z}=(V_1+V_2)[{\left(f_{o_z}\right)}_0-\stackrel{\‾}{f_{o_z}}]=50L\·{\min }^{-1}\×(0.21-0.1889)=1.055L\·{\min }^{-1}$

The quality of 1 minute internal consumption is:

$V_{o_2}=\frac{\mathrm{P\Δ}{V}_{o_2}{M}_{o_2}}{\mathrm{RT}}=1.38g\·{\min }^{-1}$

Wherein P is an atmospheric pressure,For oxygen molecule amount, temperature when T is gas stable state, test result is 25.3 DEG C;

So 1g tobacco leaf A is at 900 DEG C and equivalence ratioTime the combustion heat be released to:

Embodiment 4: the present embodiment is that tobacco leaf A combustion heat in the time that 700 DEG C, equivalence ratio are 1.5 burning is discharged to measuring method.

The relevant parameter that 1g tobacco sample A is 1.5 o'clock at equivalence ratio calculates and refers to embodiment 3. Furnace temp is set as to 700 DEG C, identical with embodiment 3 of other parameters. Can find out that according to Fig. 5 oxygen concentration fluctuates between 500～1100s less, carrier of oxygen volume concentrations in this interval is added and after be averaged and obtain mean volume fraction and be:

$\stackrel{\‾}{f_{o_z}}=\frac{{\∫}_{t_1}^{t_2}{f}_{o_z}\mathrm{dt}}{t_2-t_1}=\frac{{\∫}_{500}^{1100}{f}_{o_z}\mathrm{dt}}{1100-500}=19.33\%$

Therefore the volume of the oxygen of 1min internal consumption is:

${\mathrm{\ΔV}}_{o_z}=(V_1+V_2)[{\left(f_{o_z}\right)}_0-\stackrel{\‾}{f_{o_z}}]=50L\·{\min }^{-1}\×(0.21-0.1933)=1.675L\·{\min }^{-1}$

The quality of 1 minute internal consumption is:

$V_{o_2}=\frac{\mathrm{P\Δ}{V}_{o_2}{M}_{o_2}}{\mathrm{RT}}=1.095g\·{\min }^{-1}$

Wherein P is an atmospheric pressure,For oxygen molecule amount, temperature when T is gas stable state, test result is 24.8 DEG C;

So 1g tobacco leaf A is at 700 DEG C and equivalence ratioTime the combustion heat be released to:

。

Claims (1)

1. the result of combustion of tobacco thermal measurement method based on controlled equivalence ratio method and oxygen consumption principle, is characterized in that comprising the steps:

Step 1: calculate theoretical oxygen demand;

Tobacco sample, through elementary analysis, obtains C, H, and O, the percentage composition of S and N, sets the change of these five kinds of element compositionsCompound general formula is C_xH_yO_zS_pN_q, in oxygen lucky clean-burning chemical formula suc as formula (1),

$C_x{H}_y{O}_z{S}_p{N}_q+{\mathrm{tO}}_2={\mathrm{xCO}}_2+\frac{y}{2}{H}_{2}O+{\mathrm{pSO}}_2+{\mathrm{qNO}}_2$ Formula (1)

In formula (1)In 1g tobacco sample, Elements C, H, O, N and S fully burnWhen pyrolysis, the volume of required oxygen is:

Formula (2)

In formula (2), b is the mass fraction summation of C, H, O, S and five kinds of elements of N; M is C_xH_yO_zS_pN_qMolecular weight,Be M=12x+y+16z+32p+14q; R is ideal gas constant; P is the pressure of test gas; T is testThe temperature of gas, due to C in living beings tobacco, H, O, five kinds of element mass fraction summations of S and N are up to more than 90%,The theoretical oxygen demand of its abundant combustion and pyrolysis can represent the clean-burning theoretical oxygen demand of tobacco, and therefore this tobacco of 1g is fully firedWhen burning, theoretical air consumption is suc as formula (3),

Formula (3)

Therefore can obtain formula (4):

Formula (4), in formula, g, l refer to respectively mass unit gram and volume unit liter;

Step 2: calculate actual air supply and tobacco sample supply;

Choose equivalence ratioAccording to equivalence ratio formula (5),

Formula (5)

Calculate the ratio of the actual fltting speed of tobacco sample and the feed speed of air, suc as formula (6),

Formula (6)

The delivery rate of setting fuel is (v_Fuel)_Actual, the actual flow of air is:

Formula (7)

In formula (7), fuel delivery rate advances speed v and tobacco sample quality W to come by load sampler length L, load samplerCalculate, specifically suc as formula (8),

Formula (8)

Formula (8) is based on following processing: Wg tobacco sample is wanted on the load sampler of uniform spreading Lcm in measurement mechanism;

Step 3: according to formula (7) and formula (8), set instrument parameter, after it is stable, accurately weigh pretreated WG tobacco sample uniform spreading, on Lcm load sampler, starts experiment and measures in real time carrier of oxygen volume concentrations and temperature; Described pre-placeReason step is carried out according to standard GB/T16447-2004;

Step 4: unit of account quality result of combustion of tobacco heat discharges;

(a) calculate result of combustion of tobacco HRR;

Choose carrier of oxygen volume concentrationsThe temporal evolution interval in ± 15% of fluctuating, now can be considered stable state, asks for oxygenThe mean value of gas volume concentrations in this intervalAs formula (9),

$\stackrel{\‾}{f_{o_2}}=\frac{{\∫}_{t_1}^{t_2}{f}_{o_2}dt}{t_2-t_1}$ Formula (9)

T in formula (9)₁、t₂Respectively starting point and the terminal between the steady-state zone of choosing;

In whole combustion process, be V for the one-level charge flow rate of the tobacco of burning₁l·min^-1, cold for combustion productBut the secondary charge flow rate of dilution is V₂l·min^-1, specify V here₂≥10V₁, due to oxygen content in one-level air inletHave 21%, and the reduction of its volume number the gas that tobacco cracking burning generates, the twin-stage air inlet that therefore burning causes are made upVolume Changes is very little, and as calculated, rate of change is in ± 3%, and it can be ignored the impact of volume, that is to say, finalGas gross is still (V₁+V₂)l·min^-1So the volume of unit interval internal consumption oxygen is suc as formula (10):

${\mathrm{\ΔV}}_{o_2}=(V_1+V_2)\[{\left(f_{o_2}\right)}_0-\stackrel{\‾}{f_{o_2}}\]$ Formula (10)

In formula (10)For the initial volume concentration of oxygen, for air, be 0.21;

Internal consumption oxygen quality is unit interval so,

$v_{o_2}=\frac{{\mathrm{P\ΔV}}_{o_2}{M}_{o_2}}{RT}$ Formula (11)

In formula (11), P is ambient atmosphere pressure; T is the temperature of gas;It is oxygen molecule amount;

Result of combustion of tobacco HRR is,

$H_R=13.1\×v_{o_2}$ Formula (12)

(b) calculate the hot burst size of 1g result of combustion of tobacco

According to formula (8) and formula (12), calculate the hot burst size of 1g result of combustion of tobacco suc as formula (13),

Formula (13).