Experimental Study on Combustion of Low Calorific Oil Shale Semicoke in Fluidized Bed System

Abstract

Oil shale semicoke produced from the oil shale retorting process causes great hazards to the environment due to its high phenol and polycyclic aromatic hydrocarbons content. A good solution of the current of semicoke is to burn it as feedstock. In the present work, the extremely low calorific oil shale semicoke of 2384 kJ/kg was adopted, and a series of experimental investigations and computational analyses were carried out in bench-scale and pilot-scale bubbling fluidized bed combustors, to understand its combustion characteristics. Results indicated that by adopting effective technique means, the extremely low calorific oil shale semicoke could be directly burnt in the fluidized bed combustor, and the combustion was completely relying on its heat release. The main influence factors of combustion stability were combustion temperature, fluidization air temperature, and burnout rate. However, within the scope of test parameters, its combustion characteristics were mainly affected by dense-bed temperature, fluidization air velocity, and grain size, and less affected by static bed height. Furthermore, its comprehensive utilization system was put forward, and the general configuration and technical data of 35 t/h medium pressure fluidized bed boiler adopting the mixture of fine oil shale and extremely low calorific oil shale semicoke whose calorific value is 2876.2 kJ/kg were also given at the end of this article.

The characteristics and kinetics of co-pyrolysis of furfural residue with oil shale semi-coke

“…This implied negative interactions between SC and FR and an undesirable course of the co-pyrolysis process. This might be explained by the presence of minerals such as SiO 2 , Al 2 O 3 , Fe 2 O 3 and CaO in SC [14]. Previously it has been demonstrated that the active acid sites in Al 2 O 3 could catalyze the decomposition of biomass [8].…”

Effects of Associated Minerals on the Co-Current Oxidizing Pyrolysis of Oil Shale in a Low-Temperature Stage

“…Oil shale, a kind of unconventional petroleum resource with massive reserves, has attracted more attention in the last few years due to the contradiction between the increasing global energy consumption and shortage of conventional nonrenewable fossil fuels, such as crude oil, coal, and natural gas, 1 which is 10 times more than the liquid petroleum reserves, making it a great potential to become an alternative for conventional fossil energy. 2 The kerogen, contained with a proportionally large amount in oil shale, can be converted into hydrocarbons by thermal degradation, which is the prevalent method of oil shale utilization. 3,4 However, the thermal decomposition of oil shale requires high energy input, such as heating crude oil shale to 550 °C with 700 °C hot carrier gas, which is the most challenging obstacle to oil shale pyrolysis.…”

“…Oil shale, a kind of unconventional petroleum resource with massive reserves, has attracted more attention in the last few years due to the contradiction between the increasing global energy consumption and shortage of conventional nonrenewable fossil fuels, such as crude oil, coal, and natural gas, which is 10 times more than the liquid petroleum reserves, making it a great potential to become an alternative for conventional fossil energy …”