Temperature rise time TRT

Temperature rise time (TRT) The time required for a pyrolyser to go from its initial temperature to the final temperature. 

Once a Teq is chosen, a second problem must be solved. A given elevated temperature cannot be reached instantly even for a small mass of material. It always requires a short interval of time. This interval is referred to as temperature rise time (TRT). Pyrolysis units capable of generating isothermal conditions in a very short TRT (flash pyrolysis) are commonly available. 

During the temperature rise time (TRT), the kinetic constant k will vary. Assuming a linear temperature increase with the rate q and starting at To, the temperature is given at a certain moment t by the formula ... 

The yield of different pyrolysis products depends on the cellulose quality such as the average value for DP. the proportion of low molecular weight polymer, crystallinity, as well as the water content and the acidity of the sample. The experimental conditions influencing the chemistry of the pyrolysate include the equilibrium temperature Teq, temperature rise time (TRT), total heating time (THT) (see Section 4.1), and pyrolysis experimental setup [25,26]. A variation in pyrolysis products depending on cellulose type is exemplified in Table 7.2.1. This table gives the yield of gases, tar, char, and water for two commercially available celluloses [13]. 

Another parameter selected for analytical pyrolysis experiments is the temperature rise time (TRT). This parameter measures the time necessary for the heating element of the pyrolyzer to reach Teq. The goal in flash pyrolysis is to have a very short TRT, such that the decomposition of the sample takes place, virtually, in isothermal conditions. 

Temperature rise time TRT and total heating time THT... 

The microreactor system proposed at the University of Calgary has been subsequently used to study the ultrapyrolysis kinetics of n-hexadecane, a gas oil model compound, n-hexadecane (about 12 fig per sample) has been pyrolysed at temperatures ranging from 576 to 842°C for reaction times of 100 to 3200 ms (including the temperature rise time TRT) and pressures in the range of 1 to 2 atm. 

Tan et al. (1991) extended the temperature range studied by Fairburn et al. (1990) to 1000 °C. They showed the importance of the Temperature Rise Time (TRT) on the n-hexadecane conversion at these high temperatures (Figure 9), reporting conversions of 8% and 10%, corresponding to TRTs of 100 and 125 ms, at 900°C and 1000°C, respectively. Based on these results, they defined the Effective Residence Time (ERT) in the microreactor as the time period at which the exact Curie Point Temperature would yield the same conversion as the actual reaction for the Total reaction Time (TT). According to this definition... 

The temperature rise time (TRT), i.e. the time required for the pyrolyser temperature to be increased from its initial to the final temperature, can be chosen in the range from several milliseconds to several minutes. Simultaneously, the temperature time profile (TTP), representing temperature as a function of time for a particular pyrolysis experiment, may be easily programmable. Pyrolysis may be carried out at a fast rate of temperature increase, e.g. 10 000 K s i in the case of flash pyrolysis, or the sample can be heated at a controlled rate over a temperature range in which pyrolysis occurs using a stepwise, linear or ballistic heating approach characterized by a total heating time (THT) of several minutes or even hours. 

Figure 2 Schematic representation of the parameters that determine the heating profile in filament pyrolysis, namely temperature rise time (TRT), equilibrium temperature (Tgq) and total heating time (THT).

TRT Temperature-rise time diffusivity (5) Attenuation (ultrasonics) ... 

A potential disadvantage of Curie point pyrolysis is the longer TRT compared with the direct resistively heated foil pyrolysis. The temperature rise time of up to 200 ms to reach the Curie point is significantly slower and depends on the... 

Temperature rise time, heating up period in pyrolysis until the set pyrolysis temperature is reached. A fast TRT is a quality feature of the pyrolyser. 

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