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NH3NH2CH(NO2)2 crystallizes in the monoclinic P2_1/c space group. The structure is zero-dimensional and consists of four ammonia molecules, four ammonia molecules, and four dinitromethane molecules.
(NH2)2(NH3)2Cl2 crystallizes in the orthorhombic Fdd2 space group. The structure is one-dimensional and consists of sixteen ammonia molecules; sixteen ammonia molecules; and sixteen Cl2 ribbons oriented in the (1, 0, 0) direction. In each Cl2 ribbon, Cl1- is bonded in a distorted linear geometry to two equivalent Cl1- atoms. Both Cl–Cl bond lengths are 2.44 Å.
CH3NO2 crystallizes in the monoclinic P2_1 space group. The structure is zero-dimensional and consists of two ammonia molecules, two ammonia molecules, and two HC2O4 clusters. In each HC2O4 cluster, there are two inequivalent C4+ sites. In the first C4+ site, C4+ is bonded in a bent 120 degrees geometry to two O2- atoms. There is one shorter (1.25 Å) and one longer (1.29 Å) C–O bond length. In the second C4+ site, C4+ is bonded in a bent 120 degrees geometry to two O2- atoms. There is one shorter (1.24 Å) and one longer (1.30 Å) C–O bond length. H1+ is bonded in a linear geometry to two O2- atoms. There is one shorter (1.18 Å) and one longer (1.25 Å) H–O bond length. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded in a bent 120 degrees geometry to one C4+ and one H1+ atom. In the second O2- site, O2- is bonded in a bent 120 degrees geometry to one C4+ and one H1+ atom. In the third O2- site, O2- is bonded in a single-bond geometry to one C4+ atom. In the fourth O2- site, O2- is bonded in a single-bond geometry to one C4+ atom.
CN5(NH2)3NH3 crystallizes in the triclinic P-1 space group. The structure is zero-dimensional and consists of six ammonia molecules, two ammonia molecules, and one CN5 cluster. In the CN5 cluster, C4+ is bonded in a trigonal planar geometry to three N+1.44- atoms. There is two shorter (1.35 Å) and one longer (1.39 Å) C–N bond length. There are five inequivalent N+1.44- sites. In the first N+1.44- site, N+1.44- is bonded in a distorted bent 120 degrees geometry to one C4+ and one N+1.44- atom. The N–N bond length is 1.28 Å. In the second N+1.44- site, N+1.44- is bonded in a distorted single-bond geometry to one C4+ and one N+1.44- atom. The N–N bond length is 1.33 Å. In the third N+1.44- site, N+1.44- is bonded in a water-like geometry to two N+1.44- atoms. The N–N bond length is 1.34 Å. In the fourth N+1.44- site, N+1.44- is bonded in a water-like geometry to two N+1.44- atoms. The N–N bond length is 1.33 Å. In the fifth N+1.44- site, N+1.44- is bonded in a distorted water-like geometry to one C4+ and one N+1.44- atom.
(Ti(NH3)8)2(NH3)12(Cl2)3 is Ammonia-derived structured and crystallizes in the monoclinic P2/c space group. The structure is zero-dimensional and consists of twelve ammonia molecules, six hydrochloric acid molecules, and two Ti(NH3)8 clusters. In each Ti(NH3)8 cluster, Ti3+ is bonded in a 8-coordinate geometry to eight N3- atoms. There are two shorter (2.29 Å) and six longer (2.30 Å) Ti–N bond lengths. There are four inequivalent N3- sites. In the first N3- site, N3- is bonded in a trigonal non-coplanar geometry to one Ti3+ and three H1+ atoms. There are a spread of N–H bond distances ranging from 1.02–1.04 Å. In the second N3- site, N3- is bonded in a trigonal non-coplanar geometry to one Ti3+ and three H1+ atoms. There is two shorter (1.02 Å) and one longer (1.03 Å) N–H bond length. In the third N3- site, N3- is bonded in a trigonal non-coplanar geometry to one Ti3+ and three H1+ atoms. There is one shorter (1.02 Å) and two longer (1.03 Å) N–H bond length. In the fourth N3- site, N3- is bonded in a trigonal non-coplanar geometry to one Ti3+ and three H1+ atoms. All N–H bond lengths are 1.03 Å. There are twelve inequivalent H1+ sites. In the first H1+ site, H1+ is bonded in a single-bond geometry to one N3- atom. In the second H1+ site, H1+ is bonded in a single-bond geometry to one N3- atom. In the third H1+ site, H1+ is bonded in a single-bond geometry to one N3- atom. In the fourth H1+ site, H1+ is bonded in a single-bond geometry to one N3- atom. In the fifth H1+ site, H1+ is bonded in a single-bond geometry to one N3- atom. In the sixth H1+ site, H1+ is bonded in a single-bond geometry to one N3- atom. In the seventh H1+ site, H1+ is bonded in a single-bond geometry to one N3- atom. In the eighth H1+ site, H1+ is bonded in a single-bond geometry to one N3- atom. In the ninth H1+ site, H1+ is bonded in a single-bond geometry to one N3- atom. In the tenth H1+ site, H1+ is bonded in a single-bond geometry to one N3- atom. In the eleventh H1+ site, H1+ is bonded in a single-bond geometry to one N3- atom. In the twelfth H1+ site, H1+ is bonded in a single-bond geometry to one N3- atom.
ClONO2 is Ammonia-derived structured and crystallizes in the trigonal R3m space group. The structure is zero-dimensional and consists of three ammonia molecules and three ClO3 clusters. In each ClO3 cluster, O is bonded in a single-bond geometry to one Cl atom. The O–Cl bond length is 1.47 Å. Cl is bonded in a trigonal non-coplanar geometry to three equivalent O atoms.
SnSe3(NH2)5(NH3)2 crystallizes in the triclinic P-1 space group. The structure is zero-dimensional and consists of ten ammonia molecules, four ammonia molecules, and one SnSe3 cluster. In the SnSe3 cluster, Sn3+ is bonded to four Se2- atoms to form edge-sharing SnSe4 tetrahedra. There are a spread of Sn–Se bond distances ranging from 2.51–2.63 Å. There are three inequivalent Se2- sites. In the first Se2- site, Se2- is bonded in a distorted single-bond geometry to one Sn3+ atom. In the second Se2- site, Se2- is bonded in an L-shaped geometry to two equivalent Sn3+ atoms. In the third Se2- site, Se2- is bonded in a single-bond geometry to one Sn3+ atom.
(ZrH12(NF)4)2N2 is Ammonia-derived structured and crystallizes in the tetragonal P4/ncc space group. The structure is zero-dimensional and consists of four ammonia molecules and four ZrH12(NF)4 clusters. In each ZrH12(NF)4 cluster, Zr3+ is bonded in a 4-coordinate geometry to four equivalent N+2.20- and four equivalent F1- atoms. All Zr–N bond lengths are 2.43 Å. All Zr–F bond lengths are 2.08 Å. N+2.20- is bonded in a trigonal non-coplanar geometry to one Zr3+ and three H1+ atoms. There is two shorter (1.02 Å) and one longer (1.03 Å) N–H bond length. There are three inequivalent H1+ sites. In the first H1+ site, H1+ is bonded in a single-bond geometry to one N+2.20- atom. In the second H1+ site, H1+ is bonded in a single-bond geometry to one N+2.20- atom. In the third H1+ site, H1+ is bonded in a single-bond geometry to one N+2.20- atom. F1- is bonded in a single-bond geometry to one Zr3+ atom.
Rb2B2NH5(BH)8(NH3)4 is Ammonia-derived structured and crystallizes in the orthorhombic Pnma space group. The structure is one-dimensional and consists of sixteen ammonia molecules; thirty-two boranediylradical molecules; and four Rb2B2NH5 ribbons oriented in the (1, 0, 0) direction. In each Rb2B2NH5 ribbon, Rb1+ is bonded in a 3-coordinate geometry to three H1+ atoms. There are a spread of Rb–H bond distances ranging from 2.94–3.13 Å. There are two inequivalent B+1.20- sites. In the first B+1.20- site, B+1.20- is bonded in a distorted single-bond geometry to one H1+ atom. The B–H bond length is 1.21 Å. In the second B+1.20- site, B+1.20- is bonded in a distorted single-bond geometry to one H1+ atom. The B–H bond length is 1.21 Å. N3- is bonded in a trigonal non-coplanar geometry to three H1+ atoms. There is one shorter (1.02 Å) and two longer (1.03 Å) N–H bond length. There are four inequivalent H1+ sites. In the first H1+ site, H1+ is bonded in a single-bond geometry to two equivalent Rb1+ and one B+1.20- atom. In the second H1+ site, H1+ is bonded in a single-bond geometry to one N3- atom. In the third H1+ site, H1+ is bonded in a single-bond geometry to one Rb1+ and one N3- atom. In the fourth H1+ site, H1+ is bonded in a single-bond geometry to two equivalent Rb1+ and one B+1.20- atom.
The thrust of this project was to investigate the structures of important materials with potential application to hydrogen storage, in an effort to meet the DOE goals for 2010 and 2015, namely 9% (wt) and 15% (wt) respectively. Unfortunately, no material has been found, despite the efforts of many laboratories, including our own, that achieves these goals in a reversible complex hydride such as ammonia borane (NH 4 BH 4 ), and other ammonia based compounds, or with light hydrides such as LiBH 4 , due either to their irreversibility or to the high decomposition temperatures and residual simple hydrides such as LiH from the decomposition of the last named compound.
The overall objective of this project is to conduct cost analyses and estimate costs for on- and off-board hydrogen storage technologies under development by the U.S. Department of Energy (DOE) on a consistent, independent basis. This can help guide DOE and stakeholders toward the most-promising research, development and commercialization pathways for hydrogen-fueled vehicles. A specific focus of the project is to estimate hydrogen storage system cost in high-volume production scenarios relative to the DOE target that was in place when this cost analysis was initiated. This report and its results reflect work conducted by TIAX between 2004 and 2012, including recent refinements and updates. The report provides a system-level evaluation of costs and performance for four broad categories of on-board hydrogen storage: (1) reversible on-board metal hydrides (e.g., magnesium hydride, sodium alanate); (2) regenerable off-board chemical hydrogen storage materials(e.g., hydrolysis of sodium borohydride, ammonia borane); (3) high surface area sorbents (e.g., carbon-based materials); and 4) advanced physical storage (e.g., 700-bar compressed, cryo-compressed and liquid hydrogen). Additionally, the off-board efficiency and processing costs of several hydrogen storage systems were evaluated and reported, including: (1) liquid carrier, (2) sodium borohydride, (3) ammonia borane, and (4) magnesium hydride. TIAX applied a bottom-up costing methodology customized to analyze and quantify the processes used in the manufacture of hydrogen storage systems. This methodology, used in conjunction with ® software and other tools, developed costs for all major tank components, balance-of-tank, tank assembly, and system assembly. Based on this methodology, the figure below shows the projected on-board high-volume factory costs of the various analyzed hydrogen storage systems, as designed. Reductions in the key cost drivers may bring hydrogen storage system costs closer to this DOE target. In general, tank costs are the largest component of system cost, responsible for at least 30 percent of total system cost, in all but two of the 12 systems. Purchased BOP cost also drives system cost, accounting for 10 to 50 percent of total system cost across the various storage systems. Potential improvements in these cost drivers for all storage systems may come from new manufacturing processes and higher production volumes for BOP components. In addition, advances in the production of storage media may help drive down overall costs for the sodium alanate, SBH, LCH2, MOF, and AX-21 systems.
Several candidate cleaning products have been reviewed for use as a disinfectant on 9975 shipping package components which contain or have contacted mold. Following review of the compatibility of these products with each component, ammonia (ammonium hydroxide diluted to 1.5 wt% concentration) appears compatible with all package components that it might contact. Each of the other candidate products is incompatible with one or more package components. Accordingly, ammonia is recommended for this purpose. It is further recommended that all components which are disinfected be subsequently rinsed with di-ionized or distilled water.
The form factors are fundamental properties of the nucleon representing the effect of its structure on its response to electromagnetic probes such as electrons. They are functions of the four-momentum transfer squared Q 2 between the electron and the proton. This thesis reports the results of a new measurement of the ratio of the electric and magnetic form factors of the proton up to Q 2 = 5.66 (GeV/c) 2 using the double spin asymmetry with a polarized beam and target. Experiment E07-003 (SANE, Spin Asymmetries of the Nucleon Experiment) was carried out in Hall C at Jefferson Lab in 2009 to study the proton spin structure functions with a dynamically polarized ammonia target and longitudinally polarized electron beam. By detecting elastically scattered protons in the High-Momentum Spectrometer (HMS) in coincidence with the electrons in the Big Electron Telescope Array (BETA), elastic measurements were carried out in parallel. The elastic double spin asymmetry allows one to extract the proton electric to magnetic form factor ratio G p E /G p M at high-momentum transfer, Q 2 = 5.66 (GeV/c) 2 . In addition to the coincidence data, inclusively scattered electrons from the polarized ammonia target were detected by HMS, which allows to measure the beam-target asymmetry in the elastic region with the target spin nearly perpendicular to the momentum transfer, and to extract G p E /G p M at low Q 2 = 2.06 (GeV/c) 2 . This alternative measurement of G p E /G p M has verified and confirmed the dramatic discrepancy at high Q 2 between the Rosenbluth and the recoil-polarization-transfer iv method with a different measurement technique and systematic uncertainties uncorrelated to those of the recoil-polarization measurements. The measurement of the form factor ratio at Q 2 = 2.06 (GeV/c) 2 has been determined as {mu}{sub p}G p E /G p M = 0.605{+-}0.178 stat {+-}0.033 sys which is in agreement with an earlier measurement with the polarized target technique at similar kinematics. The measurement of the form factor ratio at Q 2 = 5.66 (GeV/c) 2 has been determined as μ p G p E /G p M = 0.672 {+-} 0.362 stat which represents the highest Q 2 reach with the double spin asymmetry to date.
The modern coalbed methane industry was born in the Black Warrior Basin of Alabama and has to date produced more than 2.6 trillion cubic feet of gas and 1.6 billion barrels of water. The coalbed gas industry in this area is dependent on instream disposal of co-produced water, which ranges from nearly potable sodium-bicarbonate water to hypersaline sodium-chloride water. This study employed diverse analytical methods to characterize water chemistry in light of the regional geologic framework and to evaluate the full range of water management options for the Black Warrior coalbed methane industry. Results reveal strong interrelationships among regional geology, water chemistry, and gas chemistry. Coalbed methane is produced from multiple coal seams in Pennsylvanian-age strata of the Pottsville Coal Interval, in which water chemistry is influenced by a structurally controlled meteoric recharge area along the southeastern margin of the basin. The most important constituents of concern in the produced water include chlorides, ammonia compounds, and organic substances. Regional mapping and statistical analysis indicate that the concentrations of most ionic compounds, metallic substances, and nonmetallic substances correlate with total dissolved solids and chlorides. Gas is effectively produced at pipeline quality, and the only significant impurity is N{sub 2}. Geochemical analysis indicates that the gas is of mixed thermogenic-biogenic origin. Stable isotopic analysis of produced gas and calcite vein fills indicates that widespread late-stage microbial methanogenesis occurred primarily along a CO{sub 2} reduction metabolic pathway. Organic compounds in the produced water appear to have helped sustain microbial communities. Ammonia and ammonium levels increase with total dissolved solids content and appear to have played a role in late-stage microbial methanogenesis and the generation of N{sub 2}. Gas production tends to decline exponentially, whereas water production tends to decline hyperbolically. Hyperbolic decline indicates that water volume is of greatest concern early in the life of a coalbed methane project. Regional mapping indicates that gas production is controlled primarily by the ability to depressurize permeable coal seams that are natively within the steep part of the adsorption isotherm. Water production is greatest within the freshwater intrusion and below thick Cretaceous cover strata and is least in areas of underpressure. Water management strategies include instream disposal, which can be applied effectively in most parts of the basin. Deep disposal may be applicable locally, particularly where high salinity limits the ability to dispose into streams. Artificial wetlands show promise for the management of saline water, especially where the reservoir yield is limited. Beneficial use options include municipal water supply, agricultural use, and industrial use. The water may be of use to an inland shrimp farming industry, which is active around the southwestern coalbed methane fields. The best opportunities for beneficial use are reuse of water by the coalbed methane industry for drilling and hydraulic fracturing. This research has further highlighted opportunities for additional research on treatment efficiency, the origin of nitrogen compounds, organic geochemistry, biogenic gas generation, flow modeling, and computer simulation. Results of this study are being disseminated through a vigorous technology transfer program that includes web resources, numerous presentations to stakeholders, and a variety of technical publications.
A sulfur family chemical cycle having ammonia as the working fluid and reagent was developed as a cost-effective and efficient hydrogen production technology based on a solar thermochemical water-splitting cycle. The sulfur ammonia (SA) cycle is a renewable and sustainable process that is unique in that it is an all-fluid cycle (i.e., with no solids handling). It uses a moderate temperature solar plant with the solar receiver operating at 800°C. All electricity needed is generated internally from recovered heat. The plant would operate continuously with low cost storage and it is a good potential solar thermochemical hydrogen production cycle for reaching the DOE cost goals. Two approaches were considered for the hydrogen production step of the SA cycle: (1) photocatalytic, and (2) electrolytic oxidation of ammonium sulfite to ammonium sulfate in aqueous solutions. Also, two sub-cycles were evaluated for the oxygen evolution side of the SA cycle: (1) zinc sulfate/zinc oxide, and (2) potassium sulfate/potassium pyrosulfate. The laboratory testing and optimization of all the process steps for each version of the SA cycle were proven in the laboratory or have been fully demonstrated by others, but further optimization is still possible and needed. The solar configuration evolved to a 50 MW(thermal) central receiver system with a North heliostat field, a cavity receiver, and NaCl molten salt storage to allow continuous operation. The H2A economic model was used to optimize and trade-off SA cycle configurations. Parametric studies of chemical plant performance have indicated process efficiencies of ~20%. Although the current process efficiency is technically acceptable, an increased efficiency is needed if the DOE cost targets are to be reached. There are two interrelated areas in which there is the potential for significant efficiency improvements: electrolysis cell voltage and excessive water vaporization. Methods to significantly reduce water evaporation are proposed for future activities. Electrolysis membranes that permit higher temperatures and lower voltages are attainable. The oxygen half cycle will need further development and improvement.
This final report documents the technical results of the 3-year project entitled, “Turbulent Flame Speeds and NOx Kinetics of HHC Fuels with Contaminants and High Dilution Levels,” funded under the NETL of DOE. The research was conducted under six main tasks: 1) program management and planning; 2) turbulent flame speed measurements of syngas mixtures; 3) laminar flame speed measurements with diluents; 4) NOx mechanism validation experiments; 5) fundamental NOx kinetics; and 6) the effect of impurities on NOx kinetics. Experiments were performed using primary constant-volume vessels for laminar and turbulent flame speeds and shock tubes for ignition delay times and species concentrations. In addition to the existing shock- tube and flame speed facilities, a new capability in measuring turbulent flame speeds was developed under this grant. Other highlights include an improved NOx kinetics mechanism; a database on syngas blends for real fuel mixtures with and without impurities; an improved hydrogen sulfide mechanism; an improved ammonia kintics mechanism; laminar flame speed data at high pressures with water addition; and the development of an inexpensive absorption spectroscopy diagnostic for shock-tube measurements of OH time histories. The Project Results for this work can be divided into 13 major sections, which form the basis of this report. These 13 topics are divided into the five areas: 1) laminar flame speeds; 2) Nitrogen Oxide and Ammonia chemical kinetics; 3) syngas impurities chemical kinetics; 4) turbulent flame speeds; and 5) OH absorption measurements for chemical kinetics.
UTRC lead the development of the Simulink Framework model that enables a comparison of different hydrogen storage systems on a common basis. The Simulink Framework model was disseminated on the www.HSECoE.org website that is hosted by NREL. UTRC contributed to a better understanding of the safety aspects of the proposed hydrogen storage systems. UTRC also participated in the Failure Mode and Effect Analysis of both the chemical- and the adsorbent-based hydrogen storage system during Phase 2 of the Hydrogen Storage Engineering Center of Excellence. UTRC designed a hydrogen storage system with a reversible metal hydride material in a compacted form for light-duty vehicles with a 5.6 kg H2 storage capacity, giving it a 300 miles range. It contains a heat exchanger that enables efficient cooling of the metal hydride material during hydrogen absorption in order to meet the 3.3 minute refueling time target. It has been shown through computation that the kinetics of hydrogen absorption of Ti-catalyzed NaAlH4 was ultimately limiting the rate of hydrogen absorption to 85% of the material capacity in 3.3 minutes. An inverse analysis was performed in order to determine the material property requirements in order for a metal hydride based hydrogen storage system to meet the DOE targets. Work on metal hydride storage systems was halted after the Phase 1 to Phase 2 review due to the lack of metal hydride materials with the required material properties. UTRC contributed to the design of a chemical hydrogen storage system by developing an adsorbent for removing the impurity ammonia from the hydrogen gas, by developing a system to meter the transport of Ammonia Borane (AB) powder to a thermolysis reactor, and by developing a gas-liquid-separator (GLS) for the separation of hydrogen gas from AB slurry in silicone oil. Stripping impurities from hydrogen gas is essential for a long life of the fuel cell system on board of a vehicle. Work on solid transport of AB was halted after the Phase 1 to Phase 2 review in favor of studying the slurry-form of AB as it appeared to be difficult to transport a solid form of AB through the thermolysis reactor. UTRC demonstrated the operation of a compact GLS in the laboratory at a scale that would be required for the actual automotive application. The GLS met the targets for weight and volume. UTRC also reported about the unresolved issue associated with the high vapor pressure of fluids that could be used for making a slurry-form of AB. Work on the GLS was halted after the Phase 2 to Phase 3 review as the off-board regeneration efficiency of the spent AB was below the DOE target of 60%. UTRC contributed to the design of an adsorbent-based hydrogen storage system through measurements of the thermal conductivity of a compacted form of Metal Organic Framework (MOF) number 5 and through the development and sizing of a particulate filter. Thermal conductivity is important for the design of the modular adsorbent tank insert (MATI), as developed by Oregon State University (OSU), in order to enable a rapid refueling process. Stringent hydrogen quality requirements can only be met with an efficient particulate filtration system. UTRC developed a method to size the particulate filter by taking into account the effect of the pressure drop on the hydrogen adsorption process in the tank. UTRC raised awareness about the potential use of materials-based H2 storage systems in applications outside the traditional light-duty vehicle market segment by presenting at several conferences about niche application opportunities in Unmanned Aerial Vehicles (UAV), Autonomous Underwater Vehicles (AUV), portable power and others.
This report summarizes the technical progress made of the research project entitled “Low Cost High-H2 Syngas Production for Power and Liquid Fuels,” under DOE Contract No. DE-FE-0011958. The period of performance was October 1, 2013 through July 30, 2015. The overall objectives of this project was to determine the technical and economic feasibility of a systems approach for producing high hydrogen syngas from coal with the potential to reduce significantly the cost of producing power, chemical-grade hydrogen or liquid fuels, with carbon capture to reduce the environmental impact of gasification. The project encompasses several areas of study and the results are summarized here. (1) Experimental work to determine the technical feasibility of a novel hybrid polymer/metal H2-membrane to recover pure H2 from a coal-derived syngas was done. This task was not successful. Membranes were synthesized and show impermeability of any gases at required conditions. The cause of this impermeability was most likely due to the densification of the porous polymer membrane support made from polybenzimidazole (PBI) at test temperatures above 250 °C. (2) Bench-scale experimental work was performed to extend GTI's current database on the University of California Sulfur Recovery Process-High Pressure (UCSRP-HP) and recently renamed Sulfur Removal and Recovery (SR2) process for syngas cleanup including removal of sulfur and other trace contaminants, such as, chlorides and ammonia. The SR2 process tests show >90% H2S conversion with outlet H2S concentrations less than 4 ppmv, and 80-90% ammonia and chloride removal with high mass transfer rates. (3) Techno-economic analyses (TEA) were done for the production of electric power, chemical-grade hydrogen and diesel fuels, from a mixture of coal- plus natural gas-derived syngas using the Aerojet Rocketdyne (AR) Advanced Compact coal gasifier and a natural gas partial oxidation reactor (POX) with SR2 technology. Due to the unsuccessful experimental results with the hybrid polymer/metal H2 membrane, a conventional CO2 capture (single-stage Selexol) and hydrogen purification (PSA) technologies were used in the appropriate cases. In all cases, the integrated system of Advanced Compact coal gasifier, non-catalytic natural gas partial oxidation, and SR2 multicontaminant removal with state-of-the-art auxiliary system provided a 5-25% cost advantage over the base line plants using GEE coal gasifier with conventional Selexol/Claus sulfur removal and recovery. These plants also produce 18-30% less CO2 than with the conventional coal gasification plants.