EP1521536B1 - Method for improving the loading capacity of tobacco - Google Patents

Abstract

The invention relates to a process for enhancing the filling capacity of tobacco, such as cut tobacco leaf or tobacco midribs, or tobacco additional material, by treating the tobacco material having an initial moisture of 10-30% with a treatment gas consisting of nitrogen and/or argon at pressures of 400 to 1,000 bar followed by a continuous decompression and subsequent thermal post-treatment of the discharged tobacco material. The filling density of the tobacco charge in the autoclave is greater than 0.2 kg/dm<SUP>3</SUP>.

Description

The invention relates to a method for improving the filling capacity of pressed tobacco, such as cut tobacco leaves or tobacco additives, by treating the tobacco material with a treatment gas consisting of nitrogen and / or argon at pressures of 400 to 1,000 bar followed by continuous decompression and subsequent thermal treatment of the discharged tobacco material.

Such processes, also known as INCOM blowing processes, have proven advantageous over the pressure treatment of tobacco with carbon dioxide, ammonia or volatile organic gases. Thus, DE 29 03 300 C2 describes such a blowing process with working pressures between 300 and 800 bar. The examples show a great influence of the final pressure on the fillability improvement, but only an insignificant influence of the reaction time in the range between 1 and 10 minutes. The document contains no indication of a possible pressing or compaction of the tobacco.

DE 31 19 330 C2 discloses the thermal treatment of the treated gas under pressure tobacco by steam or saturated steam and refers with respect to the high-pressure treatment to the already cited patent DE 29 03 300 C2.

Furthermore, DE 34 14 625 C2 describes a cascade process, according to which it is intended to be ensured by the most varied measures such as cooling of the treatment gas before charging the reactor, cooling the autoclave or use of a supercooled and liquefied treatment gas that the temperature of the discharged tobacco before the heat treatment below 0 ° C is. The examples are based on a filling of the 200-1 autoclave with 30 kg of tobacco, which corresponds to a filling density of 0.15 kg / dm ³ .

The patent DE 39 35 774 C2 describes the cooling of the compressed treatment gas in an autoclave via an external heat exchanger, wherein several autoclaves were connected together to form a so-called train. The process ultimately represents a special form of cooling gas and Behandlungsgut.

DE 100 06 425 C1 describes the treatment of a tobacco with relatively low moisture to about 16% at a working temperature greater than 55 ° C. From the used autoclave volume of 2 dm ³ and a tobacco weight of 300 g, a filling density of the tobacco packing of 0.15 kg / dm ^{3 is} calculated, which corresponds to the already cited DE 34 14 625 C2.

DE 100 06 424 A1 discloses decompression with at least one holding stage and heating of the system under residual pressure in order to achieve tobacco discharge temperatures of 10 to 80 ° C.

The filling densities of about 0.15 kg / dm ³ described in the prior art result when the tobacco is introduced into the pressure vessel without a further pressing process. An increase in the filling density, however, brought in the known methods with rapid pressure build-up, lower filling capabilities of the expanded tobacco material.

The object of the present invention is to further develop the known processes in such a way that they are more economical than before at comparably high filling capacity.

Surprisingly, it turns out that contrary to the teaching of DE 29 03 300 C2 in the region of high filling densities, the contact time of the compressed gas exerts a considerable influence on the resulting filling capacity of the expanded tobacco material.

Although the cited prior art describes how the basic method can be further optimized with regard to the highest possible filling capacity of the expanded tobacco material. In addition to the Füllfähigkeitsgewinn but also the tobacco filling quantity for a given autoclave volume is an important factor for the efficiency of the INCOM process. An increase in the filling quantity not only allows a higher throughput but also leads to a reduction of the specific consumption of treatment gas and compressor energy for a volume of tobacco to be expanded.

The process according to the invention is explained in more detail below with reference to examples.

For this purpose, the term "pressure time" is first defined as the sum of the pressure build-up time to the first reaching the final pressure and the optional hold time after reaching the final pressure until initiation of the decompression process.

• i. Langsamer Druckaufbau bis zur direkt nachfolgenden Dekompression
• ii. Schneller Druckaufbau mit anschließender Haltezeit, d.h. Stehenlassen des Behälters unter Druck ohne Zufuhr oder Abfuhr von Behandlungsgas
• iii. Schneller Druckaufbau mit anschließender Haltezeit, vor Beginn der Dekompression erfolgt ein Nachspeisen von Behandlungsgas, um erneut den Enddruck zu erreichen.

An inventive, sufficiently long printing time can be achieved by the following variants of the process control:

• i. Slow pressure build-up until directly following decompression
• ii. Fast pressure build-up with subsequent hold time, ie leaving the container under pressure without supply or removal of treatment gas
• iii. Fast pressure build-up with subsequent hold time, before the start of the decompression is a dessication of treatment gas to reach the final pressure again.

Since the pressure in the container drops during the holding time due to the cooling, a process control according to variant iii. Allows to set the final pressure again before the decompression. Surprisingly, this procedure leads to variant ii. to another, but low Füllfähigkeitssteigerung.

The following Examples 1 and 2 first describe the influence of different pressure times and process variants with a filling density of the tobacco in the pressure vessel of 0.15 kg / dm ³ according to the prior art:

example 1

The high-pressure treatment was carried out in a laboratory autoclave with a used content of 2 dm ³ . A jacket for the circulation of liquid media was used to set the desired working temperatures. The pressure buildup was from below, the pressure reduction upwards. Several valves enabled the intended circuit schemes. A compressor was used to set the final pressure.

The laboratory device for thermal aftertreatment consisted of a permeable wire mesh used as a conveyor belt, baffles for forming the tobacco mat in the desired width, a steam nozzle with slit-like outlet opening and a steam suction device arranged below the belt. The aftertreatment with saturated steam was carried out at a belt speed of 5 cm / s and a steam capacity of 10 kg / h.

The tobacco samples were spread in flat plastic dishes and conditioned in standard atmosphere at 21 ° C and 62% relative humidity. The filling capacities were determined with the aid of a Borgwaldt densimeter, and the specific volume in cm ³ / g was converted to a nominal moisture content of 12% by weight and a target temperature of 22 ° C. From the data of the untreated comparison or basis and the expanded patterns, the relative fillability improvement, also referred to as the degree of bulking, is calculated according to the following formula, in which F _B denotes the filling capacity of the base and F _E the filling capacity of the expanded tobacco: $$\mathrm{\Delta }\mathrm{\%}=\left({\mathrm{F}}_{\mathrm{e}}-{\mathrm{F}}_{\mathrm{B}}\right)*100\mathrm{\%}/{\mathrm{F}}_{\mathrm{B}}$$

The experiments were carried out with a tobacco moisture content of 18% by weight and tobacco scales of 300 g. The working temperature was adjusted to 40 ° C by thermostating. The final pressure was 700 bar, the decompression took place in about 0.5 min. All experiments were based on a uniform mixture of virginia tobacco and the described post-treatment method with saturated steam. The bruck construction time, the holding time after reaching the final pressure and the option of refilling at the end of the holding time were varied. Table 1 contains the compilation of the experimental parameters and the achieved relative Füllfähigkeitsverbesserungen or Blähgrade. Table 1: Relative fillability improvement (filling density 0.15 kg / l, working temperature 40 ° C, tobacco moisture 18%) process variant i. i. i. ii. ii. iii. iii. Pressure build-up time (min) 3 6 12 3 3 3 3 Holding time (min) 0 0 0 5 10 5 10 Printing time (min) 3 6 12 8th 13 8th 13 Fillability gain Δ% 67 68 72 68 68 70 71

Example 2

The experiments were carried out analogously to Example 1, but with a tobacco moisture content of 12% and a working temperature of 60 ° C. Table 2 contains the experimental parameters as well as the relative fillability improvements or degrees of swelling achieved. Table 2: Relative fillability improvement (filling density 0.15 kg / dm <sup> 3 </ sup>, working temperature 60 ° C, tobacco moisture 12%) process variant i. i. ii. iii. Pressure build-up time (min) 3 30 3 3 Holding time (min) 0 0 5 5 Printing time (min) 3 30 8th 8th Fillability gain Δ% 77 79 75 76

The results from Examples 1 and 2 make it clear that in the area of conventional stuffing densities the printing time exerts only a small influence on the filling capacity gain.

The following examples 3 and 4 show the influence of different printing times and process variants with a filling density of the tobacco in the pressure vessel according to the invention of more than 0.2 kg / dm ³ :

Example 3

The experiments were carried out analogously to Example 1, but with a tobacco weight of 500 g. The tobacco was compressed during the filling of the pressure vessel by manual pressing. Table 3 contains the compilation of the experimental parameters and the relative fillability improvements or degrees of swelling achieved. Table 3: Relative fillability improvement (filling density 0.25 kg / dm <sup> 3 </ sup>, working temperature 40 ° C, tobacco moisture 18%) process variant i. i. i. ii. ii. iii. iii. Pressure build-up time (min) 3 12 20 3 3 3 3 Holding time (min) 0 0 0 5 10 5 10 Printing time (min) 3 12 20 8th 13 8th 13 Fillability gain Δ% 55 65 71 67 68 69 69

Example 4

The experiments were carried out analogously to Example 2, but with a tobacco weight of 450g. The tobacco was heated to about 50 ° C before filling the pressure vessel using a microwave oven and compacted during filling by manual pressing. Table 4 contains the compilation of the experimental parameters and the relative fillability improvements or degrees of swelling achieved. Table 4: Relative fillability improvement (filling density 0.225 kg / dm <sup> 3 </ sup>, working temperature 60 ° C, tobacco moisture 12%) process variant i. i. ii. iii. Pressure build-up time (min) 3 20 3 3 Holding time (min) 0 0 10 5 Printing time (min) 3 20 13 8th Fillability gain Δ% 65 76 73 74

Examples 3 and 4 illustrate the influence of the printing time on the Füllfähigkeitsgewinn at filling densities of the invention of more than 0.2 kg / dm. ³ A good expansion effect can only be achieved under these conditions if the printing time exceeds a value of approx. 300 s. Furthermore, it becomes clear that at comparable printing times, the process variant iii. gives the best results.

Claims (5)

1. Process for enhancing the filling capacity of tobacco, such as cut tobacco leaf or tobacco midribs, or tobacco additives, by treating the tobacco material having an initial moisture of 10-30 % with a treatment gas consisting of nitrogen and/or argon at pressures of 400 to 1,000 bar followed by a continuous decompression and subsequent thermal post-treatment of the discharged tobacco material, characterised in that that the tobacco is mechanically compressed before, during or after the pressure vessel is filled, so that the filling density of the tobacco charge in the autoclave is greater than 0.2 kg/dm³.
2. Process according to claim 1, characterised in that the pressure time, that is to say the time between the start of pressure build up and decompression, is at least 300 s.
3. Process according to claim 1 or 2, characterised in that the tobacco is heated before or during compression.
4. Process according to claims 1-3, characterised in that the pressure time of at least 300 s is reached after rapid pressure build up by allowing the vessel to stand under pressure.
5. Process according to claim 4, characterised in that after the vessel is allowed to stand, before the decompression, renewed pressurisation is performed.