Top Fuel Injection Design in an Entrained-Flow Coal Gasifier Guided by Numerical Simulations

Abstract

A computational fluid dynamics scheme is employed to simulate the effects of potential fuel injection techniques on gasification performance. The objective is to help design the top-loaded fuel injection arrangement for an entrained-flow gasifier using coal water slurry as the input feedstock. Two specific arrangements are investigated: (a) coaxial dual jet impingement with slurry coal in the center and oxygen in the outer jet and (b) four jet impingement with two single slurry coal jets and two single oxygen jets. When the heterogeneous finite-rate solid-gas reaction scheme is implemented, it is discovered that the particle collision model cannot be implemented with the heterogeneous gasification scheme in the present computational model. The instantaneous gasification model is later employed to examine the particle collision phenomenon by implementing the particle collision model, in which the coal (consisting of carbon and volatiles) is injected as gas, and the water is injected as droplets. The result of droplet tracks shows that the droplets are not bounced around, as speculated, at the intersection where the jets meet, and majority of the droplets pass through the jet impingement section and hit the wall as in the finite-rate case. This implies that the results of the finite rate are acceptable even though the particle collision model is not implemented. The finite-rate result actually presents a worst-case scenario for predicting wall erosion. The particle tracks for both the two concentric and four separate injection configurations show that the coal particles hit the wall and can accelerate the deterioration of the refractory bricks. The case employing two concentric injections provides better fuel-oxidant mixing and higher heating values than the case using four separate injections.

Effect of Radiation Models on Coal Gasification Simulation

“…The kinetic rate of reaction is defined as: (17) The rate of particle surface species depletion for reaction order N = 1 is given by: (18) For reaction order N = 0,…”

“…In 2011, Wang, et al performed the simulation on the effects of potential fuel injection techniques on gasification performance in order to help design the top-loaded fuel injection arrangement for an entrained-flow gasifier using a coal-water slurry as the input feedstock. Two specific arrangements were investigated: (a) coaxial, dual-jet impingement with the coal slurry in the center jet and oxygen in the outer jet and (b) four-jet impingement with two single coal-slurry jets and two single oxygen jets [17]. Wang and Lu investigated the performance of a syngas quench cooling design in the ITRI downdraft entrained flow gasifier.…”

Numerical Simulation of the Multi-Component Slurry Gasification with the Non-Premixed Combustion Model

“…Further effective use for fossil fuels becomes an urgent demand for sustainable development, so more and more attention has been paid to the cleaning energy technology. As one of the critical technology, the multi-component slurry (MCS) gasification, which is a process of converting various carbon-based feedstock (coal, petroleum coke, asphalt, coal liquefaction residues) to a mixture of hydrogen and carbon monoxide, has displayed strong superiority due to the wide-ranging adaptability of raw materials, high energy utilization efficiency and low pollutant emissions [1]. Moreover, the produced syngas can be used for the synthesis of many important chemicals, such as methanol, natural gas, dimethyl ether and light olefins.…”