Pyrolysis closed-system

TCBTs are relatively persistent and non-flammable (and therefore useful in hydraulic oils). Pyrolysis in a closed system for two days in the presence of hydrogen peroxide at 300 °C produced as main components chlorinated benzo-phenones, fluorenes, fluorenones, xanthenes, and xanthones. Polychlorodiben-zofurans (PCDF) and polychlorodibenzo-p-dioxins (PCDD) were formed in much lower concentrations than from PCB product Pyralene T1 under identical conditions [84]. In pyrolysis at 450-700 °C with excess oxygen TCBTs produce more PCDFs and PCDDs. In parallel with the behavior of PCBs, PCDFs are formed in significantly higher amounts than PCDDs from PCBTs [86],... 

Other polymeric terpenes are also known in nature. One such material is the resin called dammar (recent or fossil), generated by the trees from the family Dipterocarpaceae. Pyrolytic studies were performed on this polymer [16] after separation in two fractions, one soluble in CH2CI2 and the other insoluble. Three different pyrolysis techniques were used to obtain information on the insoluble polymer, flash pyrolysis, open isothermal furnace pyrolysis and closed system isothermal pyrolysis. Several compounds separated and identified in pyrolysates by GC/MS are shown below ... 

The pyrolytic process of a repetitive polymer frequently takes place with the formation of small volatile molecules and has a polymeric chain scission mechanism, as described in Section 2.1. However, the theory developed below considers only the monomer as being volatile and does not take into consideration that other small molecules may leave the pyrolysis system (this case is sometimes indicated as a closed system). 

Dieckmann V., Schenck H.J., Horsfield B., Welte D.H. (1998) Kinetics of petroleum generation and cracking by programmed-temperature closed-system pyrolysis of Toarcian shales. Fuel 77, 23-31. 

Di Primio Skeie use compositional data from closed system pyrolysis experiments to construct a compositional kinetic model of petroleum generation from the Draupne Formation. Although this, in itself, is not new, they developed the model in a format compatible with the data resolution used in PVT models that are familiar to reservoir engineers. Most importantly, they tuned their PVT models to the observed properties of actual petroleum accumulations observed in a well-defined portion of the North Sea. This represents a significant... 

It was recently demonstrated that compositional information from closed system pyrolysis of source rock samples, when properly calibrated, can be used to reconstruct the regional distribution of hydrocarbons as a function of migration and phase separation using PVT simulation software (di Piimio 2002). While this former study was performed using PVT software it indicated the need for the development of phase predictive kinetic models for the correct simulation of secondary migration in basin modelhng. 

Compositional predictions from closed system pyrolysis... 

Table 1, Comparison of saturation pres.sure and vokimetrics of phase separation at a pres.aire of 21)0 bar for a natural fluid and the product of a closed system pyrolysis experiment of simitar GORs...

As a starting point for the tuning of our multi-component kinetic model we used kinetic data from closed-system non-isothermal pyrolysis experiments which describe the generation of oil and gas from a marine Type II source rock (Dieckmann et al. 1998). The frequency factors (A), activation energy ( ) distributions and hydrocarbon potentials of primary oil and gas generation of Dieckmann et al. (1998) were used as the framework for our model (Figure... 

A compositional kinetic model of hydrocarbon generation for a marine Type II source rock was developed based on data from closed-system non-isothermal pyrolysis experiments. The model predictions were tuned to a natural maturity sequence. The compositional data format chosen is compatible with the compositional resolution used in reservoir engineering, and allows a direct comparison of predicted compositions and phase behaviour to PVT data of natural fluids. 

Based on the pyrolysis experiments listed above we can see a much higher isotope effect in open systems than for closed systems. The isotope enrichment for both H2S and S released... 

Schenk H. J., Di Primio R. and Horsfield B. (1997) The conversion of oil into gas in petroleum reservoirs. Part 1 comparative kinetic investigation of gas generation from crude oils of lacustrine, marine and fluviodeltaic origin by programmed-temperature closed-system pyrolysis. Org. Geochem. 26, 467-481. 

FIGURE 13.2 Thermal extraction, open-system, and closed-system pyrolysis gas chromatograms of the oil-prone coal from the Heathfield-1 Well using the MSSV (microscaled seal vessel pyrolysis) method (see References 12 and 13) m = methylcyclohexane, n-alkanes (alkenes) indicate carbon number. 

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