Polygeneration of Liquid Fuels and Electricity by the Atmospheric Pressure Hybrid Solar Gasification of Coal

Abstract

An analysis of system operation and performance has been undertaken, for the first time, of a solar-hybrid coal-toliquids polygeneration facility incorporating solar resource variability. The energetic and environmental performance of a coal-toliquids process that is integrated with a solar hybridized, oxygen blown, atmospheric pressure gasifier (CTL sol ) is compared with that of a reference, nonsolar, autothermal, pressurized gasification integrated, CTL ref configuration. To allow the plant to respond to solar resource transience, pressurized storage of upgraded syngas and oxygen is incorporated into the proposed CTL sol system. The CTL sol process is simulated using a dynamic model that assumes pseudosteady state operation at each time-step, for a 12month, hourly averaged solar insolation time-series. Both the CTL sol and CTL ref systems were modeled using AspenPlus and Aspen HYSYS (v 7.1) software. The analysis of the CTL sol system's performance showed an annually averaged improvement of 21% to the total energetic output and a reduction of 30% in the mine-to-tank greenhouse gas emissions relative to the CTL ref system assuming equilibrium gasification conditions of 1400 °C and 1 bar-a. The integration of a pressurized syngas storage facility was shown to enable the CTL sol system to allow the variation in throughput of each unit of process equipment to be maintained within normal operational ranges despite the fluctuations in the transient solar input to the solar-hybrid coal gasification process.

Design and demonstration of a prototype 1.5 kWth hybrid solar/autothermal steam gasifier

“…Significant CH 4 was only observed in the experiments using lignite coal as the feedstock, possibly due to the higher volatile content and CH 4 being generated during pyrolysis. The highest = X 0.79, were observed for the activated charcoal under the high H 2 O:C conditions with O 2 where, presumably, full conversion did not occur due to entrainment of the smaller particles that did not fully react as observed after experimentation.…”

“…Product gases were temporally monitored with a combination of mass spectrometry (MS, OmniStar ThermoStar GSD320 Gas Analysis System) and gas chromatography (GC, Agilent 490 Micro GC equipped with Molsieve and PoraPLOT Q columns). The GC was calibrated for H 2 , CO, CO 2 , CH 4 , and O 2 .…”

“…Previous work has examined the concept of coupling together autothermal and solar-driven gasification processes within a single gasifier, allowing for continuous, 24-h production of H 2 -and CO-rich synthesis gas (syngas) for downstream fuel or chemical synthesis [1][2][3][4]. FischerTropsch (F-T) synthesis allows for the production of drop-in liquid hydrocarbons for the transportation sector.…”

Storage capacity assessment of liquid fuels production by solar gasification in a packed bed reactor using a dynamic process model

“…Numerous studies have investigated the key drivers of the amount of energy storage required to integrate CST collectors with power generation [1][2][3][4][5][6][7] and fuel production cycles [8,9]. These analyses have largely been based on hybrid energy systems, where CST power is indirectly introduced through a secondary thermal loop [1][2][3][4][5][6] or the combustion of fossil fuels is either supplemented through the direct introduction of CST power into a thermochemical reactor [8], directly into a boiler volume to drive a power cycle [7]. These http://dx.doi.org/10.1016/j.apenergy.2016.04.067 0306-2619/Ó 2016 Elsevier Ltd. All rights reserved.…”

“…A recent full-year process modeling analysis of a system integrating an atmospheric pressure hybrid solar gasifier with a FT liquids production system, using an hourly averaged solar dataset, showed that as little as eight hours of syngas storage was required to enable steady state operation of the downstream syngas upgrading reactor over a full solar year [8]. This analysis proposed a hybrid, continuously operational solar, entrained flow gasifier based on the experimentally proven solar vortex reactor [11,12], assuming that CST power drives gasification in the reactor volume when it is available and autothermal reactions in pure O 2 drive gasification, within the same volume, when solar energy is not available [8].…”