Key words: supercritical supercritical water, brown coal, dynamic and static conversion
Conversion of brown coal was studied in supercritical water (SCW) at pressure P = 30 MPa and temperature T ≤ 760 °C at continuous supply of coal-water slurry (CWS) from above into a vertical tube reactor. It is shown that at coal particle fall into the reactor via a conic channel under the conditions of a continuous temperature increase (the stage of dynamic conversion (DC)) from 44 (at temperature in the reactor top TtR = 400°C) to 63 % (at TtR = 750°C) of organic matter of coal (OMC) are extracted from coal in the form of liquid and gaseous products with 71÷100 % of OMC oxygen. It is shown that DC of coal is resulted from conversion product drain under the action of excessive pressure of fluid in particles, caused by a rise of particle temperature at their fall into the reactor. It is determined that the main products of DC at TtR = 400°C are the high-molecular organic substances with prevalence of resins, and at 750°C they are alkanes, aromatic hydrocarbons, H2 and CO. It is important that after DC the coal particles have filled uniformly the reactor and they did not sinter at following static conversion (SC) of coal: at SCW pumping through the layer of coal particles in the reactor. The composition of products and rate of SC depends on the temperature of the process, in particular, due to the fact that water becomes the source of hydrogen even at T > 600°C.