WO2001011357A2

WO2001011357A2 - Method of determining the oxygen requirement for the combustion of a fuel, method of combusting a fuel and an apparatus therefor

Info

Publication number: WO2001011357A2
Application number: PCT/NL2000/000558
Authority: WO
Inventors: Joseph Jan Peter Biermann; Nicolaas Voogt; Paul Amappa Dijkman
Original assignee: Cdem Holland B.V.
Priority date: 1999-08-09
Filing date: 2000-08-08
Publication date: 2001-02-15
Also published as: WO2001011357A3; NL1012798C2; AU6483000A

Abstract

The invention relates to a method for determining the amount of oxygen necessary for the combustion of a fuel. To this end a predetermined amount of the fuel is contacted with an inert liquid comprising a predetermined excess of oxidant, where the fuel is oxidized by the oxidant, after which (i) the amount of oxidants remaining after the oxidation is measured; or (ii), in the event of the oxidant resulting in a reductant, the amount of reductant or oxidant is measured, from which oxidant or reductant quantification values a value for the oxygen demand is derived. The value found can be applied for operating an apparatus in which fuel is combusted.

Description

Method of determining the oxygen requirement for the combustion of a fuel, method of combusting a fuel and an apparatus therefor

The invention relates to a method of determining^' the oxygen requirement for the combustion of a fuel.

Such a method is known in the field. The known method is usually practised by performing measurements in a combustion apparatus, wherein per unit of time a known amount of fuel is combusted and the consumption of gaseous oxygen is measured by measuring the oxygen concentration in flue gas using an oxygen concentration meter.

A drawback of the known method is that due to a slow response of the apparatus to a new fuel, it requires much time and is inaccurate.

The object of the present invention is to provide a method wherein in a relatively fast manner an accurate value for the oxygen demand during the combustion of a fuel, such as a fuel of an unknown or variable composition, may be determined.

To this end the method according to the present invention is characterized in that a predetermined amount of the fuel is contacted with an inert liquid comprising a predetermined excess of oxidant, whereby the fuel is oxidized by the oxidant, after which i) the amount of oxidant remaining after the oxidation is measured; or ii) , in the event of the oxidant resulting in a reductant, the amount of reductant or oxidant is measured, from which oxidant or reductant quantification values a value for the oxygen demand is derived.

Thus, it is possible to determine the oxygen demand for various solid or liquid fuels, as well as solidified or liquefied fuels, amongst which i) mineral fuels such as lignite, oil shale, oil, and products thereof such as plastic, and ii) biomass of various origin, such as sewer sludge, loppings, vegetable-, garden-, and fruit refuse (composted or not) , wood from thinning and wood grown for the purpose of energy generation, wood from demolition, wood left-overs and waste wood. The method according to the invention measures the consumption of oxydant by "wet chemistry"; a predetermined amount of fuel is introduced into a solution comprising an excess of a chemical oxydant. After the reaction, the remaining amount of oxydant or the resulting reductant is measured wet-chemically (titration) . The amount of oxydizing agent required is subsequently mathematically converted into the amount of oxygen used. Such a measurement based on weighing and titrimetrical determination is very accurate. In the present invention an inert liquid is understood to be a liquid which under the reaction conditions applied can not be oxydized by the oxydant. In the present application the term combustion is, of course, understood to be thermal combustion, something which, like the other terms used in the application, require no clarification for the ordinary person skilled in the art. In general, if it is solid after dehydratation, the fuel will comprise at least 25% dry matter. At least 10% of the dry matter will be organic material. If the fluid is a liquid fuel, the organic content will be at least 10%.

The invention is in particular suitable for those fuels whose combustion results in a solid residue. For example, it is known to use paper sludge or waste paper as fuel yielding a solid residue which, under suitable operating conditions, results in a useful product, such as disclosed in the European patent 0,796,230. For well controlled operating conditions, the varying composition requires an adequate determination of the oxygen demand. Thus, according to a preferred embodiment the fuel is paper sludge or waste paper.

According to a convenient embodiment of the method according to the invention, the value for the oxygen demand is used for determining the net heating value of the fuel.

It has been found that a direct correlation exists between the oxygen demand measured according to the invention and the fraction of organic material in the fuel. Builders of furnaces usually know from experience the cor- relations between the fraction of organic material in the fuel and the energy contents of the fuel (the net heating value) for a particular fuel. For known fuels with a varying content in incombustible material (such as paper sludge which contains a variable amount of clay) , the fraction of organic material may be determined using the method according to the invention and knowing the oxygen consumption for 100% organic material. From this the net heating value can be calculated. Because of the above-men- tioned correlation, the net heating value may also be derived directly from the oxygen consumption, as will be shown later. Thus, the present invention provides in addition a convenient method of determining this parameter which is of so much importance for both the design and the operation of incinerators.

In order to determine the net heating value, it is known to use a bomb calorimeter. Here the fuel together with an excess of oxygen is introduced in a container (the "bomb"), after which the fuel is ignited. The bomb is placed in an absorbing energy-medium, whose increase in temperature is measured and thus allowing determination of the energy released during combustion. However, in particular with fuels containing a solid residue (such as calcium carbonate) , mineralogical conversions occur which are not necessarily the same as those that occur under the combustion conditions which prevail in the apparatus for combusting the fuel. Because a mineralogical conversion is associated with a change in enthalpy, this introduces inaccuracies during the determination of the oxygen demand based on thermal measurements. The present invention circumvents this problem.

According to another favourable embodiment of the method according to the invention the oxygen demand is determined by measuring the chemical oxygen demand (COD) . The determination of the chemical oxygen demand, such as according to the Dutch standard NEN 6633, is a widely known method which is used for the determination of the pollution of waste water and such. This simple determination comprises boiling the sample to be analyzed in a medium of strong sulphuric acid in the presence of silver sulphate and mercury (II) sulphate with an excess of potassium dichromate and subsequently the determination of the amount of kalium dichromate consumed titrimetrically. For the determination of the oxygen demand of a fuel which can not be oxydized under these conditions, the fuel may be subjected to a pre-treatment , such as chemical reactions aimed at making the components in the fuel to be oxydized more readily accessible for the oxydizing agent. Here ring-opening reactions may be contemplated, which are disclosed in the standard literature on organic chemistry. In addition, halogenation may be contemplated (also described in the standard literature on organic chemistry) with the objective to improve the solubility of the compo- nents to be oxydized. In addition, the addition of surfactants may be contemplated, capable of improving the solubility of the substances to be oxydized. The application of these pre-treatment methods will later require a correction of the oxygen consumption, if any, of the organic components of these substances. Preferably, no organic pre-treatment agents are used, keeping the correction and the possibly associated measuring error at a minimum. Various variants of methods for determining the chemical oxygen demand are known. For example, US 3,540,845 discloses a quick method which may simply be performed by an unskilled person. It is also known to automize the method, such as disclosed in the French patent document 2,110,742.

The present invention also relates to a method of combusting a fuel whereby oxygen is supplied for sustaining the combustion, characterized in that the amount of oxygen supplied with respect to the amount of fuel is controlled subject to the value determined for the oxygen demand of the fuel . This allows, effective optimization of the operating conditions.

If it is required by law to retain a certain residual concentration of oxygen in the flue gasses, it is also possible to very accurately establish such a residual concentration by using the method according to the invention. This prevents that too large an excess of oxygen (i.e. significantly more than the residual concentration of oxygen required by law) is used. The present invention also relates to an apparatus for the combustion of a fuel with a concomitant supply of oxygen, characterized in that the apparatus is dimensioned subject to the value of the oxygen demand as determined by the method according to the invention. This means that the apparatus does not need to be larger than necessary. This reduces the capital outlay, while there is also a saving in operational cost, as the use of the minimally necessary amount of oxygen results in limiting the cost for its supply. By avoiding too high a flow rate, abrasion due to entrained solid residue particles and thus wear of the apparatus may be reduced.

Hereinafter the invention will be elucidated with reference to a number of exemplary embodiments and the drawing, wherein Fig. 1 shows the values for the oxygen demand (grammes 0₂/kg paper residue) determined by using the method according to the invention compared with the measured and mathematically converted amount of organic material (g organic fraction/kg paper residue) . Fig. 2 shows the 0₂-consumption (g/kg) of different reference materials plotted against their energy contents;

Fig. 3 shows a comparison between the theoretical and the actually measured values for the oxygen consumption for compounds of a few organic compounds mixed with a filler.

The oxygen demand of a paper residue-stream from a paper factory (the dry matter-fraction contained about 40% organic material, 30% clay and 30% chalk) is determined. To this end, an assay is used for the determination of the chemical oxygen demand according to the Dutch standard NEN 6633. In short, 1 to 5 g of an optionally dried representative sample of the paper residue is taken and suspended in 900 ml water. Of the thus obtained suspension 10 ml is taken and added to a potassium dichromate-comprising sul- LO LO t to H

LΠ O LΠ o LΠ O LΠ ro OJ Ω rr ς. rr s: t D, CΩ CΩ rt ⁾ Ω H- T. _^__^ CO 0i U3 2 LQ 0> Φ CO Ω 3 _ to C TJ Ξ Φ TJ

Φ tr H- rr C 0⁾ φ Φ Φ Φ C H- H- α C co 0 (3d c CO Φ Φ P- 0⁾ H- ϋ Φ CO tr H- X tr

3 CΩ SD ΓT H- H rr O tr n Ω Ω H 0 H I-¹ φ CΩ CO Ω d 3 0⁾ 3 3 Φ α φ Φ rt Ω C

Φ n P i 0 Φ Φ 0 0 0 0 0 tj <^ 3 Φ ; H- 0⁾ tr TJ 0J 0⁾ Ω Ω 0 Φ o 3 tr Φ ii tr LQ OJ 3 h 3 3 3 3 tr φ 3 3 φ rr . H rt c Λ; 0 α TJ tr α 0> X Ω 1 O H- c 0 Φ rr H- TJ . O T) 0⁾ n 0 3 CΩ CO Φ TJ 0J φ « rr 0J 3 01 ω Ω

X rr H- , . rr rt 0 ω 0 0 0 rt C H H — rr ω o Φ Φ t-¹ 01 TJ Φ 3 3 rt 3 rt H- 0 OJ 0 ω • CΩ ω ω φ CΩ tr I-¹ — 0 Φ H- 3 H- to TJ Φ α 00 fi Φ tr 3 0 0J a P 3 tr H- μ- H- H- H- C Φ o CΩ H CΩ 0 LQ CΩ _^-_^ Ω ^• φ ^ Φ φ 0J tr ii 0 Hi Ω

. 0 CΩ ι-^y rt > rr rt rr Tl I-¹ c O rr a TJ π 0 rr rt CΩ Φ 0 3 H-

< LΠ Φ H- c o H- H, H- H- H- φ tJ rr 3 Ω 0⁾ 3 . CΩ φ 0 0 rr rr c H- TJ Q.

CΩ rt o 0 0 0 0 M tr 0 TJ Φ 3 rt H- TJ Ω H- TJ 0> TJ H ζ ii 3 H- C 0

- TJ φ H- P Φ 0 1-1 3 0J LQ tr P. 3 ω Φ 0 CΩ 0 ^< d 3 rt H- 01 3 3 rt CΩ rr n α o rt 3 N rr Φ CΩ 1 H CΩ CΩ o C 01 o_ H- H- tr 3

H Φ ii rt σ rt LQ α φ 0J O rr • rr H- φ rr O rr rt o Φ 3 Φ 0 ^m. 3 0 3 3 rt Φ LQ Φ H- CO

^ rr H OJ C •ϋ C C3 rr tr -¹ φ 0 t-h 0 ^ Hi rr Φ Φ _^ 0J •i CO C

Φ U> O Φ rf> rr tr 0⁾ 0 tr tr ^ Ω Φ α H rr Φ Ω CO α ≤ 0⁾ α CΩ 0 H- rt o Φ Φ H π Φ φ Φ 0 H rt . 01 ?o to OJ Φ o _^-« H- • H- 3 Φ 0J 3 P H-

» l-¹ Φ 3 s α Hi - rt ? 3 H- 0> tr cn 3 H- 3 α t-¹ Φ Hi t-¹ 0 <! a H- 3 O

> H- — rt H- H- H- Ω •o ≤ 0 tr H- o Φ 0, s; CO ii c H- α 3 3 rr < 3 • £ φ rr 0⁾ 0⁾ ω co 0 H H- 3 0 Ω • to Ω c tr H- H- H- C H- 0 a Ω H α tr 3 0 Φ H- n tr 3 3 H- rt c tr o o Φ φ Φ 3 ΓT 3 CO α 3 tr rt Φ rr — - H-

Φ H- ϋ H rr φ α ^►a T) Ω ω tr rr φ. o CO - tr rr c: Φ • t Ω ω Ω H

O rr ^ tr Hi o • H- 0⁾ o o CO Φ υ. rt i Φ rr 0 H- OJ C- tr rt

S3 Ii 0> tr Φ £ ω 0 rr 0) 0 3 H H- o - 0J <! Oi o 0⁾ J ω IT CO Hi *r\ ω ct j-¹ ϋ

Φ 0 LQ ; OJ ^ 0 0 tr Ω < CΩ LQ O CQ • CO S i H- CΩ o tr rt 0⁾ tr 0 TJ 0 H- rr H Φ rr !-J rt φ φ H- c LΠ TJ ω LQ H- i-¹ H- o> rr 0 CO 0 H- ii tr 3 ω t φ 3 H tr C H- α ω 3 H- J TJ Φ • 0 3 H Φ 0 3 • z J 3 ω • 0J 0J

Φ σ φ OJ OJ Φ rt 3 ω Φ . C- 3 LQ rr 0 tr h ^ l-¹ ^• 3 α 3 3 rr rr tr o Φ fu 3 3 H- LQ 0 H- tr rt — C rr H O M ^. H TJ rt TJ M Φ Φ 0 σ> t-¹ X ω CΩ 3 O 3 C TJ ≤ 0> 3 C Ξ 3 — 3 tr tr tr ii 3 H-

OJ C H- 0 n 3 o C rt Ξ H tr 1 0 0J 1 CΩ tr¹ O H- OJ 0⁾ 0i H- Φ 0 Φ H- φ O ω H-

3 to φ rr 3 0 Hi rt 0 H- H- 0 rt 3 CO 0⁾ 0⁾ CΩ rt rr H- H ≤ CO Hi rr 0 ω Φ

&. I-¹ φ H- H- H- 0 H- H- rr Ω M Φ c: rt H- tr O CΩ Φ rr co CO rr 3 0J φ Φ α

CΩ fti 3 3 O c; ω rr 0 0⁾ tr H- Ω H- c 0 & rr 0 ii Φ TJ C Φ rr 3 rr H i C

^_" d ω LQ 3 3 H- tr 3 0⁾ Ω • Φ LΠ TJ 3 H- Φ • - » H Φ i rr tr 0J tr 0J rt φ LQ

. CΩ -¹ 3 O Φ TJ 0⁾ Ω Ω H < Φ Ω Φ tr Φ Φ tr H- rt Φ o rr TJ H- LQ ς- H- H- 0⁾ Ui LQ 0 tr rr 0 i Φ ^• Ω CO H- CO o 0 O Φ t3

H φ o tr 0 TJ ω ω Φ Ω Ω C H- Hi H- Φ 3 H- 0. H- 0 Ω Hi 3 N 0 φ Hi 3 H rt t o Φ H- 0 rr TJ 0 O — H- tr P 0⁾ Ω Ω TJ 3 - Φ 3 ϋ H- rt Φ φ K ~ 3

Φ φ 3 P 0 tr tr a CO rt CΩ 3 tr tr 0 LQ rr H- Ω tr « rt O; ^ 0J C H- ^ n (D rt Φ C o Φ H- Φ 0 ω Φ ts O H- &. Φ tr Φ 0i LQ 0 CΩ 3

Φ rr 3 Φ H J 3 rr h¹- 0⁾ Φ CΩ . — . ^►9 0 - H- Hi 3 H- t3 Φ & ii CO tr φ Hi Ω P- Φ Hi

X •i OJ 0 H g φ H- rt ø H P rt tr 1 3 ? rr 0 3 rt Φ Φ φ 3 a 0 3 Q- 0

OJ 0 TJ Hi — - 3 O Φ φ ω ⁾ O Φ tr φ 01 ** H- ii Ω LQ rr O 0J fu DJ 0J I-¹ LQ H n -J co H- rr P P* Q, φ α 3 φ 0i rt 0 O 0 Φ Hi TJ rt •<; 3 0 t rr Φ o H- rr C φ Φ H LQ rt Φ s: » 0 P CΩ Hi t-¹ h _". TJ H- Φ £ 0 ^ to o 13 tr tf H- LQ ,-, Φ H α CΩ J tr rt 0 . 3 I-¹ P tr 3 _^-_^ K. rr .. — , Φ TJ rr a φ M 1 α. CΩ ^ Φ O ti rr rr H VD o H- Hi H- LQ φ 0J 0J rt tr cn 3 rt tr s: α Ul 3 • H- •• Ω 0⁾ 0 CO C 0⁾ 0⁾ C O o P f φ 3 C Ω H- 0

0⁾ n < tr Oi rr H- rr rt O 0 t- Ω tr H- CΩ rr • ^j 01 O <J

Φ rr Φ rr tr H α ct tr rr c

3 tr <J LO 3 Φ C tr Φ 3 rt H- < ⁾ o rr 3 0⁾ φ o 0J ii ii ω 0 £ Φ 3 tr Φ ^ n rr tr Φ O TJ rr i H- O o\o H- rr l-¹ rt 3 3 0J ω

H- rr ω TJ — tr Φ ^ 0 H- P 3 rt D -• LQ 0 CO 0 Ω 0 - LQ c φ H- LQ rr rr rr H- ω Φ Hi φ 3 C 0 3 Φ φ ii N Φ H-

H- 3 0 i 0 H- J < 0⁾ Φ O H

0 LQ 0J H. 0⁾ 0⁾ 0 . 3 tr

3 3 Hi φ

point is determined by the position of the strongest decrease in electrode voltage.

The oxygen demand is calculated using the following formula 0.5 M COD = (V, - V,) C ^•

wherein: COD is the chemical oxygen consumption in mg oxygen per litre

V_x is the amount of water processed: 20 ml V₂ is the amount of iron (II) ammonium sulphate solution used in the blank assay: 16.88400 ml V₃ is the amount of iron (II) ammoniumsulphate solution used during the assay: 8.21236 ml c is the concentration of the iron (II) ammonium sulphate solution used: 0.1448 M M is the atomic mass of oxygen: 16,000 mg/mol .

From this it follows that the value found for the chemical oxygen demand equals 502.4 mg 0₂/l. 1 litre solution V_L contains (1000 ml/20 ml)* (10 ml/900 ml) * (1, 0070*0, 909) g glucose = 0,508 g. Thus the oxygen consumption for glucose is 502,4 mg/0,508 g = 988 mg 0₂ per gram glucose (hydrated) . From Fig. 2 it can be seen that the energy content is 12.6 MJ/kg. This is in good agreement with the value determined using Dulong's formula (12,9 MJ/kg) for the chemical composition known for this substance.

Fig. 1 shows the results in a graph, wherein the oxygen demand (grams 0₂/kg paper residue) is plotted against the measured and converted amount of organic material (g organic fraction/kg paper residue) . The values on the X-axis were obtained as follows. The organic material content is calculated based on a determination of the mass of dry substance (DS) , by drying the sample to be measured at 150°C to constant weight. The resulting dry sample was calcined at 900°C, whereafter the amount of ash LO LO to to H o o O rt H- O μ- H LO 3 H CD Ω tr _{^ ^ r} M rt Ω _^^.._^ H H- - a α 0J O O OJ 0J H- rr TJ H i hi

H 3 rr ω OJ OJ Φ P tr ^> LQ LQ X tr O s Φ 3 OJ Φ 0⁾ TJ Hi Hi CD H, Φ tr ii tr CΩ φ

0 rr tr tr -— > 3 OJ 0J φ ii -i Hi TJ rt CO rr TJ Φ CO Φ Φ φ tr CΩ

3 Φ Φ tr TJ OJ TJ H O O 3 H ""*--_. Φ O P Ω Φ φ rr rr rr μ- CD μ-

H H OJ Φ c tr rr rt t 0 t t TJ φ φ i i i CD 0⁾ tr tr tr TJ D. 0J φ Hi hi

0 Hi CΩ ϋ Φ Φ H- • LQ α t⁾ LQ Φ rt Φ H- ϋ φ Φ φ i C CΩ 3 0 Φ P

Hi φ s- Φ -¹ Φ ω 0 Φ CO φ Φ 0⁾ — a 0J tr « CD H- φ Φ tr rt - CO φ

H 0 TJ tl * . 3 1 ϋ rt Ω <τi a O Φ Φ CO CD ii CO 1 1 1 -¹ μ- rt Φ ii tr LQ ii s H H- to LQ H- φ H- Ω Hi rt 0J 0J φ 0⁾ ii 0» O ϋ s; tr 0 Φ φ Φ 3 0 TJ Hi LQ ;

TJ O Tl LQ φ tr 3 3 H 3 rt O φ rt CD rt ≤ P 0J φ t. CO 3 t-¹ C Φ 3 tr > t O P ϋ 3 rr 0⁾ 0i TJ TJ Φ rt tr CΩ tr tr μ- Φ CO

P- - 0 Ω H- OJ r (0 Φ tr i 0 Ω 0 OJ 0 tr tr ≤ rr ?r μ- φ π Φ rt a

0 rr 0 Ω CO rr LO rt 0 tr 3 rr to Hi Φ 0 H- Φ Φ TJ μ- 0i J LQ ^»

X tr CO tr CΩ rt £ P tr 0⁾ rr rt a Φ Φ < rt rr Φ a 0 0 P CO o Ω OJ Φ

P Φ • Φ Φ P- ii M- rt Φ ω o> tr Φ d rt rr rr fi CO rt 3 Φ tr tr H- Ω Ω rt Φ μ- 0J 0i CΩ rt Q o tr - Φ — ' φ ii Φ Φ tr H- tr tr ω 0J rr tr tr μ- CΩ φ φ rr CO 3 H tr rt Φ Φ TJ 3 Φ 0J o φ rr . rt 3 H- o Φ 3 0J μ- i Ω CD

Ω tr H- φ a. hi a tr rt φ tr H- rt Φ t-^y Φ 0J tr tr 3 rr <3 rr ii CΩ Ω 3 μ- P Φ 3

Φ OJ OJ Φ ^• t OJ rt Ω Hi C LQ a Ω CO 3 0 Φ φ tr tr Φ tr _^~. 0J P 3 rr μ- ii 3 CD 0> tr Ω 0J rt H- φ

Ω r rt φ Φ Ω 01 O D. t > CΛ 3 T Φ 3

Φ Ω c Ω ^ rt Φ Ω Oi 3 CΩ Hi rt LQ J ( O TJ rr rt Φ tr O rt o μ- 0J μ- rt ii Φ

3 3 Φ hj OJ tr 0 T tr r H- 0 O X tr 3 O rt rt a 3 Ω μ- 3

OJ φ CΩ Φ OJ φ α i TJ tl 1-3 tr t

Φ I 0 Φ 0 φ ii •i Φ H- Φ TJ p to r φ Ω α o O μ-

3 r C Ω P 0 Φ α o rt tr tr Φ rt CΩ 0J φ LQ rr & 0 . ct , tr CΩ £ hf LQ H- OJ H- φ Φ 0 rt O Ω tr Ω 0J OJ Φ Φ 0J P to 0J 3 a a

D a OJ tr TJ CD Φ H

• 0 P ^• i 3 H rt to a rr X H- Φ 0J ii 0 rt Ω tl i CO CO

. a CO Φ 0 tr α Ω OJ OJ Ω Φ LQ ω ii

Hi Φ H- tr rt Hi *< rr 1

Ω H- 3 tr μ- C3 P £ Φ φ tr £ LQ Ω Ω H- P

CO tr rr tr

Φ φ Φ 0J OJ O Ω tr ii ^ 0 Ω H- ω

H- OJ 0 rr rt Ω 0 Φ 1 H 3 ^• ! μ r o 3 0 ti Φ P

P > μ- ii Q, H ω Ω

OJ φ O ii 0 0 tr Φ μ-

0 0 3 TJ LQ a H I-¹- 3 Hi M φ D, - • a μ- tfl Φ tr o CO 3 ? Hi 0⁾ 0J H • r Ω H TJ 0J H- - 3 Φ O ω

Φ Ω Φ H- P H- α Φ to ^ 0J LQ

Hi rr rt r a Φ

0⁾ rt 0J a J - 3 μ- r W μ- μ- 3 LQ 3

3 Ω 0 0 H- tr 0 tr H- rt Ω LQ Ω Q 3 d Φ L tr Φ C φ O 0J 3 J rr P Ω o Ω 3

0J a 0J μ-

0 hj Hi 3 φ X Φ rr P-. H- H CΩ φ a ct LQ 0 a P rt 0 0 OJ α X Ω rr OJ *< tr *

3 Ω CΩ CD rr < CΩ ii rt H- 3 tr Φ rt a 3 rt Φ 1 0J

^• M rr CO LQ TJ φ 3 P H- 0 rt

LQ OJ Φ H- Φ O O α H- Φ & J tr hi

OJ O tr OJ OJ Φ H- H 3 rr rt φ hi 3 3 Φ O- X TJ tr tr a O <! D, a to OJ 0J o TJ φ 0J

Hi OJ O H- φ rr tr a

3 Λ° H- TJ a μ- p: 0J •<3 Ω

Hi CO φ Φ

Ω φ LQ Ω O rt OJ Φ rt <. tr Φ rr μ- α a tl TJ OJ O

Φ 0. rt 0 tr c Φ 0 tl ii O >_ rr H-

•^ LOT tr 0J OJ φ ^ a tr a & Φ CΩ Hi 3

Ω TJ

Ω C φ CO CΩ 3 rt Φ s: ω O »i Φ C φ rt rr CΩ t tr - TJ rt LQ a Ω φ a rt CΩ α c: H- 0 Φ tr rr tr p 0 tr ii 0 Φ Φ tr Φ rt Φ 3 3 rr 3 Φ tr Φ 0J H O i Φ hj ϋ to P H- rr

O tr ct tl 3 Φ CQ tι ii Φ <. rr μ- Φ Φ tr φ OJ tr M 3 ω rt rt 0 TJ <! Hi TJ φ

H- ii Φ < 0J X Φ Ά tr 3 TJ 0 Φ CO ω φ rr

Φ ?r O 0 Ω 1 Φ ti 0 Φ rt TJ , . a H- Φ Φ 0J 0J H μ- μ- O μ-

C H- H- ≤ rt Φ Ω rr tl O CΩ LQ ti Φ Φ Ω rr LQ μ, TJ CΩ μ- TJ Ω z 0 tr Ω 0 a H- 3 0 0J t⁾ P H- •^ Hi rt ω a O H- i 0J Φ tr LQ ϋ P p φ 3

Φ t O 0⁾ CΩ 0 rr X 0J ω 3 CO ϋ CΩ 1 H- ω

< 3 O φ ii μ- Φ φ φ 3 ct H- rt H- 3 H- ^ ^•< Φ P φ Ω

0J O 0J O rr H- 3 H" 3 ii a ω Ω 0

Φ Ω OJ t⁾ 0 LQ rt 3 Φ 0J M a ϋ a tr <J Φ 0J Hi μ φ 0J φ 0J 0J 0⁾ φ Hi μ, tr a CΩ TJ Φ φ ii Ω P- ii Φ Ω tl CO hj

3 Ω OJ Φ ^►*_ tr t3 3 1 ω rt 0J

C C-. rt H-

0 rt O rr 3 0J CO μ- ct φ _^ rt

H- Φ I-¹ Φ H- OJ Ω fl H- i a H- Φ P Φ i Ω μ- o. TJ o X tr

3 • P LQ rr 0 Ω Φ O α. ii ii φ rr φ a β H O o α P 0J μ- 0J to μ-

OJ a Φ rt Φ ii μ- c Φ TJ i 1 3 H Ω a Q 1J

1 ω

CΩ 0i 1 O Φ Φ

3 Φ 1 rt CD o a ti •

TABLE 1

Claims

to t H

LΠ o LΠ O

u