Title: INTEGRATED GASIFICATION COMBINED CYCLE IGCC PROCESS IMPROVEMENT THROUGH PROCESS SIMULATION AND HEAT
1INTEGRATED GASIFICATION COMBINED CYCLE (IGCC)
PROCESS IMPROVEMENT THROUGH PROCESS SIMULATION
AND HEAT INTEGRATION F. Emun, M. Gadalla, L.
JiménezDepartment of Chemical engineering,
School of Engineering, University Rovira i
Virgili, Av. Països Catalans 26, 43007 Tarragona,
Spain. E-mail fiethamelekot.emun_at_urv.cat
RESULTS AND DISCUSIONS
INTRODUCTION
2. Heat Integration
- IGCC technology is increasingly important in the
world energy market, as low-cost feedstocks such
as coal, heavy oils, pet coke and biomass are
among the best alternatives. - It is an alternative technology to pulverized
coal (PC) combustion systems because it produces
low-cost electricity and meets strict
environmental regulations. - The potential for Carbon dioxide sequestration
makes IGCC more appealing and environmentally
responsible.
- Integration of the gasifier and the combustor
1. Sensitivity analysis
- The increase in the level of integration has a
positive effect on the thermal efficiency at
first, because it results in a drop in O2carbon
ratio in the gasifier and favors the gasification
reaction than the combustion reaction. - With further integration, the carbon conversion
efficiency drops thereby lessening the thermal
efficiency.
- cold gas efficiency
- Tgasification
- thermal efficiency
- CO2 and SOx
emissions - This is due to a lower level of O2Carbon ratio
to the gasifier thereby favouring the
gasification reaction than the combustion
reaction.
- Eventhough the thermal efficiency is droping, the
emissions keep on decreasing because the air
inlet to the combustor decreases to maintain the
specified high temperature in the combustor
OBJECTIVES
The goal of this research is to improve IGCCs
process efficiency and environmental performance
through process simulation, heat integration and
optimization.
- Integration of the air separation (ASU) and the
gas cleaning units
- Combustion temperature and level of N2 injection
METHODOLOGY
The maximum is shifted to the left with the
efficiency improved. The maximum efficiency is
reached at a combustor duty of 150MW (unlike
200MW in the previous case) due to the further
decrease in the O2Carbon ratio as the O2 inlet
temperature to the gasifier increases.
CONCLUSIONS
The thermal efficiency increases almost linearly
with the increase in the combustor temperature
for all levels of N2 injection to the combustor.
Therefore, the power augmenting effect of the N2
flow is greater than its diluting effect in the
combustor.
The Ultimate thermal efficiency (LHV) that is
attained is 45 with CO2 and SOx emissions of
698 kg/MWh and 0.15 kg/MWh respectively. It
corresponds to a gasification temperature of 1250
ºC, a syngas combustion temperature of 1550 ºC,
98 of N2 injection to the gas turbine combustor,
and a slurry solid concentration of 80. The
combustor heat duty for optimum integration with
the gasifier is 150MW (for the case of the ASU
and gas cleaning unit heat integration).
Modifications
- Solid concentration in slurry feed
Modifications
- Heat Integration
- Pinch Analysis
- The main functional relationships
- Coal f(Gas turbine net power)
- Slury water f(Coal)
- Steam water f(stack temperature)
- ASU Air f (gasifier net heat duty)
- GT Air f (combustor net heat duty)
Except the concern with flowability of the
slurry, the higher is the solid concentration,
the better will be the thermal efficiency with
smaller emissions.