Lowering the Cost and Environmental Impact of Direct Coal ...Lowering the Cost and Environmental...
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Lowering the Cost and Environmental Impact of Direct Coal Liquefaction
through Wave Liquefaction™ Technology
James J. Strohma*
, Mark D. Beardena, Benjamin Q. Roberts
a, Tricia D. Smurthwaite
a, Alan A. Johnson
b,
George Skoptsovb
aPacific Northwest National Laboratory, 902 Battelle Boulevard MSIN K2-44, Richland WA 99352
bH Quest, LLC, 1444 N. Euclid Ave., Pittsburgh PA 15206
*Corresponding author; ph 509-375-3862; email [email protected]
ABSTRACT
Conventional coal-to-liquids (CTL) technologies require the use of relatively high temperatures (>
425°C), residence times (minutes), and pressures (> 100 atm) to rupture chemical bonds within the coal
and overcome mass transfer limitations associated with hydrogenation of the coal and coal liquids. The
correspondingly large CTL reactors, operating at high temperatures and pressures, lead to significant
capital and operating costs, along with high water consumption and carbon dioxide emissions.
To overcome the inherent challenges of conventional liquefaction, Battelle, Pacific Northwest
Division and H Quest, LLC, have developed a novel CTL technology, named Wave Liquefaction™. This
new technology utilizes focused microwave/radio-frequency energies to activate and facilitate coal and
natural gas conversions directly to liquid oils. Consequently, the working pressures can be reduced to as
low as 1 atmosphere, bulk process temperature less than 200°C, and residence times less than 0.1
seconds. The Wave Liquefaction™ process has also been shown to be able to directly process natural gas
with coal, thus potentially eliminating the need for separate hydrogen generation facilities, further
reducing costs and the environmental impact of producing liquid products from coal.
Continuous bench-scale studies of the Wave Liquefaction™ technology have been performed on a
variety of coals including subbituminous, high-volatile bituminous and low-volatile bituminous coals.
The projected oil yields from these tests were 2 to 4 barrels per ton, with evidence of higher API gravity,
lower viscosity, and reduced asphaltene and aromatic content compared to conventional direct
liquefaction processes. Current predictions for Wave Liquefaction™ suggest early “nth plant” installed
plant costs under $36K per barrel of daily oil production and $30 to $41 per barrel for production costs
(with 12%IRR and no by-product credit), which is substantially lower than the costs of competing
technologies.
INTRODUCTION 1.0
Coal to liquids (CTL) technologies can be broken down into two main classifications, indirect
liquefaction and direct liquefaction. For indirect coal liquefaction (ICL) the coal is first gasified into
synthesis gas (predominately CO and H2) followed by Fischer-Tropsch synthesis to generate various
chemicals and fuels. ICL processes typically operate under severe operating conditions (temperatures of
~1400°C and pressures between 10-60 bar), resulting in high capital and operating costs. Furthermore
ICL has the largest environmental footprint of CTL technologies due to high water consumption and high
CO2 generation (~706-894 kg CO2 per barrel of product)[1].
Direct liquefaction generally has a lower environmental impact and has improved thermal efficiencies
for production of fuels and chemicals from coal. Direct coal liquefaction (DCL) technologies span a
wide-range of thermal processing technologies including: 1.) pyrolysis methods similar to processes
developed by Bergius in the 1920s; 2.) hydropyrolysis methods similar to Occidental; and 3.) solvent-
based processes including solvent extraction, solvent refining, and solvent donor processes developed by
numerous institutions including, but not limited to, Chevron, Gulf Oil, C-E Lummus, Exxon,
Hydrocarbon Research (now Hydrocarbon Technologies), Nippon, and Shenhua. Generally DCL
processes utilize thermal energies (with or without hydrogen, catalysts, solvents, and/or hydrogen donors)
to cleave weaker bonds within the coal to generate various liquid, solid and gaseous products. Of the
DCL technologies developed, variations of donor solvent processes have been advanced further and show
improved economics over other processes. The current state of the art DCL technology can be considered
to be catalytic multi-stage liquefaction (CMSL) developed by Hydrocarbon Technologies and the
variations of this technology currently being commercialized by Shenhua. The process blends coal with a
low-cost catalytic material (typically Fe-based) and hydrotreated recycle oil and is fed through two
liquefaction stages that operate in the temperature range of 435-460°C and a pressure of ~170 bar.
Although numerous factors affect the economics of capital and operating costs associated with
CMSL, the two-stage liquefaction reactor units typically have the highest plant costs followed by
hydrogen production units. Operational costs for CMSL are increased due to the liquefaction reactors
operating at high pressures, relatively high temperature, relatively long residence times and the need for
high pressure/high purity hydrogen. Over the last few decades significant progress has been made in
improving the overall oil yields, coal conversion, and costs associated with CMSL. However, high
capital costs (CAPEX) and operating costs (OPEX) along with environmental considerations have
prevented DCL technologies from being fully realized in the United States. To specifically address these
challenges, Pacific Northwest National Laboratory along with H Quest, LLC have been actively engaged
in the development of an alternative to conventional DCL, the Wave Liquefaction™ technology.
Wave Liquefaction™ (WL™) technology has the potential to overcome many challenges inherent to
conventional CTL technologies. WL™ process uses a unique reactor system to directly convert coal and
natural gas to liquid products using microwave/radio-frequency energies at atmospheric pressure with a
short residence time (less than 0.1 seconds). By eliminating the need for operating under severe process
conditions with high throughput, WL™ CAPEX and OPEX are anticipated to be significantly less than
current state-of-the-art. In addition, a WL™ system is able to process natural gas and coal directly. This
would eliminate the need to separately generate hydrogen, and thus eliminates the CAPEX, water
consumption, and carbon dioxide (CO2) emissions associated with a hydrogen plant.
The focus of this paper is to summarize experimental results and preliminary process and economic
analysis performed on two baseline coals (a sub-bituminous and a high volatile bituminous) at a
production rate of 75,000 barrels per day (bpd) liquid product. Experimental results demonstrate
relatively high yields for an un-optimized, single-pass system and, importantly, low gas make, indicating
reduction in secondary cracking reactions. To determine the economic feasibility of a WL™ process, a
preliminary process and economic analysis was performed to compare WL™ technology to the state of
the art CMSL baseline DCL technology based on two studies done for the Department of Energy that
contained significant information on process configuration and individual plant block flow components
[2-4].
METHODOLOGY 2.0
2.1 Experimental
Two coal samples were evaluated as part of the current study. The first coal (HQ#1) was a high-
volatile bituminous coal provided by H Quest. The second coal (HQ#2) was a sub-bituminous coal
obtained from the Penn State Coal Sample Bank (DECS-26, Wyodak). Ultimate and proximate analyses
were performed on HQ#1 and HQ#2 by independent laboratories and the raw coal properties are
presented in Table 1, along with Illinois#6 and Black Thunder coals as reported by the baseline studies.
WL™ testing was performed using a bench-scale continuous flow reactor developed at PNNL for
each coal under a variety of conditions. The bench-scale WL™ system utilizes microwave and/or radio-
frequency electromagnetic energies to directly convert coal and natural gas (methane) to liquid products.
Further details on the experimental testing and results are subjects of future publications, but a summary
of the operational features of WL™ process are as follows:
As-received coal is physically mixed with an iron-based catalyst and fed to the reactor along
with reactive gases (hydrogen and/or methane) with no additional coal drying or pretreatment
The coal mix and gases are swept through a feed tube into a main reaction zone at atmospheric
pressure and room temperature, were microwave energy is introduced using conventional
microwave generators and components that are widely available
Coal feed rates vary with given properties of a coal, but are typically in the range of 100-200
grams per hour. With typical oil yields (pentane soluble liquids) >60 wt% on a dry ash free
(daf) basis.
Low gas yields <5wt% (daf) are observed even for low rank coals. Methane can be directly fed
and converted along with the coal in the reactor system, with average methane conversion
>50%.
Table 1. Ultimate and Proximate Analysis of the Coals used in the Current Study
2.2 Basis for Techno-Economic Analysis
To analyze the WL™ process and develop CAPEX estimates for a full scale WL™ process, an
overall mass flow was developed using experimental results for liquid yields and gas compositions from
bench-scale testing. Process flows were used as input to AspenPlus for modeling of unit operations for a
full-scale WL™ process with a daily liquid production rate of 75,000 barrels per day (bpd).
CMSL process was selected as a baseline technology for economic comparisons. Studies by Bechtel
on a hv-bituminous (Illinois#6) coal [2, 3] and by SRI on a sub-bituminous (Black Thunder) coal [4]
provide some of the most definitive economics and process analysis for DCL of representative United
State coals. These studies served as a basis for comparison of WL™ process applied to HQ#1 and HQ#2
coals, respectively. Besides evaluating CMSL as applied to two different coal ranks, other differences in
the two studies were the final products obtained from the overall CTL process and the methods of
hydrogen production. Bechtel’s analysis [2, 3] included raw liquefaction product upgrading using
distillation and distillate hydrotreaters to produce a “finished” fuel product; while SRI’s analysis [4]
produced a synthetic crude as a final product. Hydrogen production units used within Bechtel’s study
were based on natural gas steam reforming, while SRI’s study generated hydrogen from coal gasification.
These differences can lead to drastically different CAPEX and OPEX requirements and final decisions on
process configurations largely depend on site locations and feedstock prices. To obtain a best
representation of the economic feasibility during the early stages of WL™ technology development and
to avoid complications in the current study, direct comparisons for each coal were made to the baseline
report for that particular coal rank. For HQ#1 the final product produced was a hydrotreated finished fuel
using the same process configuration used in the Bechtel report. While for HQ#2 the final product was
synthetic crude using the same process configuration in the SRI report. It should be noted that PNNL and
Ultimate and Proximate
Analyses (wt%)
HQ#1
(as-received)
Illinois #6a
(as-received)
HQ#2
(as-received)
Black Thunderb
(as-received)
Carbon 73.69 67.71 51.42 55.07
Hydrogen 5.31 4.57 4.16 6.22
Nitrogen 1.77 1.37 0.69 0.79
Sulfur 0.52 3.05 0.32 0.34
Oxygen (by difference) 9.29 7.67 11.53 10.50
Ash 7.96 10.94 5.58 5.87
Moisture 1.44 4.69 26.30 21.21
Total 100% 100% 100% 100%
Volatile matter 42.14 33.06
Fixed carbon 48.46 35.06
BTU/lb lower heating value 13,277 8,951 a as reported by Bechtel [2, 3]
b as reported by SRI [4]
H Quest are currently evaluating process configurations producing both synthetic oil and finished
products from each coal type. This full techno-economic evaluation with sensitivity analysis should be
performed to determine the most applicable process configuration for any given coal and site location.
RESULTS AND DISCUSSION 3.0
3.1 Process Description
Figure 1 shows a block flow diagram of the conceived WL™ process. To the degree possible,
process elements similar to CMSL or well understood process elements were utilized. CAPEX was
estimated using a combination of process modeling; literature values; parametric estimates; and, in the
case of the WL™ reactors themselves, a process plant concept. The WL™ process flow shown in Figure
1 includes color shading to identify the basis of design and cost estimate for the individual plant areas.
Unit operations shaded tan are unit operations in proposed WL™ process that are the same units used in
the CMSL reports. CAPEX estimates for these factored unit operations were made using a scaling
exponent of 0.8 to adjust equipment costs for the changed capacities for WL™ versus CMSL processing
of each coal. Additional details for each additional unit operation with different estimating basis are
discussed in section 3.2.4.
Figure 1 Overall Wave Liquefaction™ process flow diagram for HQ#1 with product upgrading
For the WL™ process, the coal preparation section includes grinding of the as-received coal, but not
cleaning or drying. Coal cleaning is not necessary because the process is compatible with incoming fines
and debris as verified during experimental testing. Coal and natural gas are fed into the reactor with a gas
recycle stream consisting of light hydrocarbons (C1-C2), hydrogen, and acid gases. A purge stream from
Coal PrepWave
Liquefaction™ Solids / Tar
RemovalLiquid
Quench
Compression / LPG Separation
Gas Oil Hydrotreating
Acid Gas Removal /
H2 purificationNatural Gas
Coal
Gas Recycle
Process Water
Power Generation
Sulfur Recovery
Sulfur
Resid & Fines
Gas Purge
LPG
Slurry to power generation
Atm / Vac Distillation
Naptha Hydrotreating
Solid Liquid Extraction (ROSE SR)
SprayQuench
ExtractRecycle
Light DIstillate
Heavy Distillate
Gas Oil
Naphtha
Recovered Lt Gas
Recovered Hydrogen
Ammonia Recovery
H2S
Ammonia
LeanOil
To combustion
Conceptual
ASPEN Simulation
Literature
ASPEN & IECM
Factored
this recycle removes sufficient gas to provide hydrogen to the hydrotreaters and remove acid gases. A
heavy oil recycle stream is also fed to the reactor as a mechanism to recycle residuum to extinction.
Products from the liquefaction reactor are sent to a spray-quench tower where solids and heavier tar
(≥850) are removed. The solid/tar bottoms are sent to a critical solvent deashing plant, where heavy oil is
extracted, used as a quench spray, and the net heavy oil is recycled to the WL™ reactor. The gas product
from the quench tower goes to a pre-flash tower where light hydrocarbons (C1-C4) along with hydrogen
and acid gases, are separated from the main liquid product. The liquid product is sent to atmospheric and
vacuum distillation where the major liquid products are separated. The gases from the pre-flash tower are
compressed and liquefied propane and butane products removed. The remaining uncondensed gases are
recycled back to the reactor or sent via a purge stream to a gas-treatment system where carbon oxides,
ammonia, and sulfur-containing gases are removed and hydrogen is recovered. Recovered hydrogen is
sent to the hydrotreaters, while ammonia and sulfur-containing gases are sent to a Claus plant for sulfur
recovery.
3.2 WL™ Process Analysis of HQ #1 (hv-Bituminous Coal)
CMSL Baseline Adjustment for HQ#1 3.2.1
Due to compositional difference between HQ#1 and Illinois #6 coals (shown in Table 1), adjustment
of CMSL CAPEX and OPEX estimates were made based on differences in sulfur, hydrogen, and ash
content. These adjustments were made assuming that the process would achieve the same heteroatom
removal and product carbon to hydrogen ratio as for the coal used in the original study (Illinois #6). Total
liquid product production was kept constant and coal feed rates adjusted accordingly. The equipment was
scaled to account for the feed rate changes resulting from the different coal. Economic parameters were
also adjusted to bring cost to a year 2010$ basis using the Chemical Engineering Plant Cost Indices
(CEPCI). Table 2 shows the CAPEX for the major process components both from the original study
(1991$) [2, 3] and CAPEX adjusted in this study to reflect 2010$. Additional adjustments for HQ#1 coal
were made using a scaling exponent of 0.8 to estimate equipment costs for changed capacities due to
compositional differences between HQ#1 and Illinois coal.
Table 2 Major Unit Operation CAPEX as Reported by Bechtel [2, 3] for Illinois #6 Coal and
Adjustments to 2010$ Made in this Study for Illinois#6 and for HQ#1 Coals.
WL™ Process Material Balance for HQ#1 3.2.2
A mass balance was developed for HQ#1 using experimental data for the product yields and gas
make. The mass flow was then adjusted as follows:
An elemental mass balance was developed to match feed and product carbon, hydrogen, sulfur,
nitrogen, oxygen, and ash.
Product rates and carbon-hydrogen ratios were assumed to match CMSL ratios as provided in
Bechtel’s CMSL study [2, 3]. Experimental work, to be reported in future publications, have
demonstrated that WL™ produces an oil composition with improved properties compared to
CMSL which could further favor WL™ material balances and economics.
Heteroatom distribution was assumed to match CMSL
A recycle methane-hydrogen stream was added with an assumed 50 percent conversion of the
methane to product, hydrogen, and char (experimentally derived average methane conversion)
The resulting mass balance was then used for modeling to predict WL™ process power requirements
and unit operation scaling factors. The final, overall mass balance is shown in Table 3. This includes an
adjustment for hydrotreating the C5+ liquid product, with changes in liquid yield and gas make.
Table 3 Estimated Mass Balance and Process Flows HQ#1
Power Estimation 3.2.3
Possibly the most significant factor for the economic viability of the WL™ process is the process
power requirement. The largest contributors to the process power demand are expected to be microwave
power used in the WL™ reactor. Complex reaction chemistry and phase behavior for a large number of
chemical compounds in the reactor preclude direct heat of reaction and phase equilibrium determination.
Fortunately, a reasonable estimate can be made by using AspenPlus.
For this analysis, 1) the feed components, temperature, and pressure conditions were specified; 2) the
product distributions, temperature, and pressure were specified; and then 3) the enthalpy difference
between the reactants in and products out were calculated by AspenPlus. Because enthalpy is a state
function, the resulting enthalpy difference is a reasonable analog for enthalpy changes induced by the
WL™ process.
The specified feeds (i.e., methane [natural gas], hydrogen, and coal) were delivered to a reactor at low
pressure and temperature. Specified products (i.e., unconverted methane [natural gas], hydrogen, carbon
oxides, water, light hydrocarbons, hydrocarbon liquids in the vapor state including single and multi-ring
aromatics, paraffins, and naphthenes) were produced by the reactor at a temperature of 1000°F (637°C).
The exact product hydrocarbon compounds were not fully resolved, but were assumed to be
hydrocarbon liquids with a boiling range represented by 39 hypothetical components with properties,
including heat of formation calculated by AspenPlus. A Microsoft Excel® input calculation block was
used to introduce the feed coal properties, gas quantities, and output conditions into an “RYield” reactor
block that calculated the enthalpy difference between the inlet and outlet streams. This enthalpy
difference between the feed and products in MMBtu/hr was then converted to electric power input to the
process. This power requirement did not include heat loss, radiation loss, or conversion efficiency of
electricity to microwaves or acoustics. The power estimate to produce 75,000 BSPD in this manner is
450 MW. A net power for the process is initially estimated at 600 MW to account for electrical
conversion efficiency to microwaves, including the power factor and additional process power
requirements.
CAPEX Estimating 3.2.4
The CAPEX for the major elements of the process block flows were developed using various
approaches depending on the degree to which the process was known, or similar to the CMSL. Unit
operations considered to be similar to CMSL and scaled appropriately were:
Product hydrotreating, ammonia recovery, and sulfur recovery CAPEX were assumed to be
identical to CMSL and scaled based on mass flow rate using a scale exponent of 0.8
Hydrogen purification, solvent deashing, and gas plant were assumed to scale with mass flow
rate, with a scale exponent of 0.8
Off sites with the exception of power generation were assumed identical to the CMSL
Coal preparation from CMSL was used with elements of drying and cleaning removed
Unit operations estimated based on other methods are outlined and described as follows:
1. WL™ Reactors
The WL™ reactors were assumed to be fabricated from simple steel pipe acting as a waveguide with
microwaves, recycled gases, and catalyst directed down the axis. Coal is introduced into the pipe a
short distance from the microwave entrance. A maximum of 5 MW was assumed for the microwave
reactor. There are assumed to be 6 trains with 20 reactors, 1 hot quench vessel, and 1 cold quench
vessel for each train. Two gas swept pulverizers are fed from two crushed coal silos.
2. Quench Towers
The quench towers were assumed to consist of six hot quench towers and six cold quench towers with
corresponding pumps and exchangers. The quench tower simulation results from AspenPlus
(providing quench tower size, heat exchanger area, and pump size) were passed to Aspen Process
Economic Analyzer that produced an installed cost for this equipment. In the model, the WL™
products enter the bottom of a large vessel and are contacted by a countercurrent stream of liquid
flowing from the top of the vessel through various arrangements of grid decks, trays, or tower
packing used to promote good gas-liquid contact. Some of the WL™ product vapors condense and
are removed from the partially cooled gas stream by gravity. Coal solids are also largely removed
from the gas into the falling liquid. Then, the hot liquid and solid slurry at the bottom of the column
are pumped through heat exchangers for cooling. Next, the cooled liquid flows, under pressure, to the
top of the tower where the cycle repeats. Heat from the circulating oil generates medium pressure
steam in the heat exchangers. A second quench tower reduces the gas temperature to about 105°F
and condenses additional liquid components from the gas by transferring the heat to cooling water.
Gas is delivered to the gas plant for further treatment to remove heteroatoms. The optimum energy
recovery and tower overhead temperatures were believed to be near optimal; however, no
optimization was performed.
3. Atmospheric and Vacuum Liquid Separation Distillation Columns
Atmospheric and vacuum liquid separation distillation columns were estimated from Gary et al. [5].
Costs in 2010$ were $82.9 million per atmospheric crude unit of 75,000 BPSD and $40.3 million for
a vacuum unit of 15,000 BPSD.
4. Power Plant
A commercial-scale power plant was assumed to provide power to the WL™ CTL plant. The power
plant size was set at 600 MW to provide power for the WL™ reactors, gas compression, pumps, other
electrically powered systems, and steam for process distillation and plant auxiliaries . The power
plant was estimated as a full green field power plant using the Carnegie Mellon/DOE Integrated
Environmental Control model [6]. This model includes a substantial amount of equipment (e.g., coal
pulverizers, cooling tower, electrical distribution, water treatment, buildings, and site preparation)
that supports the WL™ plant as a whole. In this estimate, the entire power plant cost is maintained
and adjustments made to other OSBL costs to prevent redundancy.
The fuel for the power plant was assumed to be the liquefaction char. This char has high ash content
and therefore, a circulating fluidized bed (CFB) system was selected as the most appropriate system.
A CFB can burn high-ash, low-volatile fuels. The 2010$ estimated overnight CAPEX for a net 600
MWe green field power plant (632 MW gross) was $1,138 million. The plant included a CFB boiler
with bed limestone addition, a baghouse, and a natural draft cooling tower.
Table 4 HQ#1 CMSL and WL™ CAPEX
CAPEX Comparison – HQ#1 3.2.5
Table 4 provides a comparison between the CAPEX for CMSL and WL™ processes for HQ#1 coal.
Because of the conceptual nature of WL™ technology, a contingency of 30% was added to the WL™
associated equipment. Even with this addition, WL™ CAPEX is estimated to be about 40 percent less
than the CMSL CAPEX.
The major difference is due to the significantly lower cost of the WL™ reactor system itself. This is
primarily a result of differences in pressure and residence time for the two processes. CMSL operates at
~3200 psia and a residence time of minutes, versus near atmospheric pressure and a residence time of
seconds for WL™ process. The CMSL reactors are therefore significantly larger and more costly.
Another major difference is the cost of hydrogen production and hydrogen purification associated with
CMSL. Finally, it appears that WL™ process does not require coal to be cleaned or dried, although it
may be economically desirable to do so.
3.3 WL™ Process Analysis of HQ#2 (Sub-Bituminous coal) The comparison baseline for HQ#2 was derived from SRI evaluation of CMSL technology applied to
a sub-bituminous coal (Black Thunder) [4], which is very similar to the Wyodak coal used for the HQ#2
studies (mined from the Black Thunder Mine within the Powder River Basin). With the exception of
bringing costs to a 2010$ basis, no adjustments were made to the CMSL parameters based on coal
properties.
WL™ Material Balance for HQ#1 3.3.1
Similar to the approach to HQ#1, a process mass balance was developed for HQ#2 based on
experimentally derived product balances from testing of as-received coal mixes (with ~26wt% moisture).
Experiments performed on both as-received and dried HQ#2 coal generally resulted in similar product
yield distributions indicating the advantage of WL™ process being able to handle lower rank / high
moisture coals and lignites.
Table 5 Mass Balance and Process Flow Estimates for HQ#2 Coal
First, an elemental mass balance was developed to match feed and product carbon, hydrogen, sulfur,
nitrogen, oxygen, and ash. A conversion of 60 percent was selected as an average oil production.
Methane consumption was assumed to approximate experimental results and adjusted to match hydrogen
elemental balance. Heteroatom disposition was assumed to match CMSL. No product hydrotreating was
included. The resulting mass balance is shown in Table 5.
The CAPEX estimates for HQ#2 were more simplified and used factored estimates from HQ#1 for
WL™ process power and equipment requirements. As with HQ#1, CMSL CAPEX was adjusted to 2010$
and byproduct recovery was assumed the same for CMSL and WL™. The major process configuration
differences between the analysis for HQ#2 and HQ#1 is that for HQ#2, the CMSL plant produces
hydrogen from coal gasification and no product hydrotreating is included. Coal gasification to produce
hydrogen is inherently more capital intensive than natural-gas reforming, however, this was the approach
taken by the study because of feedstock price differences [4]. Analyzing alternate configurations for
CMSL was beyond the scope of this effort, thus product hydrotreating was not included for CMSL of
Blank Thunder coal and therefore not included for WL™ estimates for HQ#2.
Table 6 shows the CAPEX comparison between CMSL and WL™ processing of HQ#2 coal. Similar
to HQ#1 the main CAPEX difference between the two processes is the reduction in the liquefaction
reactors due to the ability of WL™ to operate under mild conditions, even with 30% contingency added.
Furthermore the costly gasification plant for CMSL can be eliminated due to hydrogen production within
the WL™ reactors. Lastly WL™ technology has the ability to process high moisture coals with little to
no negative impact on the oil product yields, resulting in additional CAPEX savings compared to CMSL
technologies where some degree of coal drying is necessary.
Table 6 CAPEX Estimates for CMSL and WL™ of HQ#2
3.4 Economic Evaluation
A simple economic assessment was performed, based on achieving a 12 percent IRR on equity using
the assumptions given in Table 7. This approach was used to establish a comparison basis between
CMSL and WL™ to eliminate capital financing or other economic assumptions as a source of variability.
Additional estimating bases included:
Operating variable and fixed costs were assumed to be a function of CAPEX.
Coal and natural-gas feedstock prices were derived from Energy Information Administration
values for coal prices per BTU as delivered and natural gas Henry Hub spot price.
No value was provided for byproduct production (note that in the case of CMSL, a significant
amount of C3 and C4 is generated and in the case of WL™, a byproduct ash concentrate).
Table 7 Economic Parameter Assumptions
The results of from the simple economic analysis for WL™ and CMSL are shown in Table 8. As a
result of WL™ operating at lower pressures and temperatures than CMSL, the impact on the final
estimated product value is reduced for both HQ#1 and HQ#2 coals. For HQ#1 it is estimated that
hydrotreated “finished” fuel products are valued at ~$41/bbl to achieve a 12% IRR, which represents a
cost reduction of ~21% for similar products produced via CMSL. WL™ processing of HQ#2 is estimated
to yield synthetic crude valued ~43% lower than CMSL to achieve the same desired 12% IRR. The
increase in the estimate cost savings for HQ#2 over HQ#1 is primarily due to the increased difference in
CAPEX required for HQ#2. It is noted that the estimated cost savings between HQ#1 and HQ#2 cannot
be directly compared since the final products produced in each estimate are different. Evaluation of
alternative products and process configurations are necessary to realize the full potential of WL™
technology for the production of high-valued fuels and chemicals from various coals. However, based on
preliminary analysis, WL™ process is a technically and economically viable route for direct coal
liquefaction.
Table 8 Summary of the Economic Analysis for WL™ Compared to CMSL
CONCLUSIONS 4.0
Preliminary process and economic feasibility studies of a novel direct coal liquefaction technology,
Wave Liquefaction™, demonstrate the potential of using alternative technologies for producing fuels and
chemicals from coal. Based on experimentally derived product yields, preliminary process material
Financial Parameters
Escalation during construction 3.60%
% debt 50%
% equity 50%
% interest on debt 4.50%
Years of loan 15
Income taxes 38%
Economic life, yrs 20
Years, construction 5
Distribution during construction 10%, 30%, 25%, 20%, 15%
Depreciation 20 year 150% declining balance
Equity IRR 12%
Other factors
Variable costs, % CAPEX 1.5%
Fixed costs, % CAPEX 3.5%
Escalation for fuel and expenses 3%
Catalyst cost, $/ton $100
Catalyst, % coal feed 5%
Capacity factor 85%
Annual operating hours 7446
balances were developed for a 75,000 bpd WL™ process. CAPEX and OPEX estimates for WL™
process were developed and directly compared to the existing state-of-the-art CMSL. Due to the unique
application of microwave and radio-frequency energies WL™ enables high conversion of coal to oil
products (>60wt%, daf) at mild operating conditions results in substantial CAPEX savings. Through the
ability to directly co-process coal and methane within a WL™ process, additional CAPEX savings are
possible by eliminating the need for separate hydrogen production units. The preliminary techno-
economic analysis performed in this study demonstrates the economic feasibility of WL™ processes for
the direct coal liquefaction of coal. Production of liquid fuel products is estimated to have daily
production costs between $30 and $41 per barrel of liquid product at 12% IRR and no by-product credit.
ACKNOWLEDGEMENTS 5.0
Wave Liquefaction™ technology development performed at Pacific Northwest National Laboratory
is supported by H Quest, LLC under contract numbers 61615 and 63585. H Quest, LLC, the general
partner of H Quest Partners, LP, is a privately held technology company, based in Pittsburgh,
Pennsylvania, focused on the development and commercialization of novel hydrocarbon conversion
technologies.
REFERENCES 6.0
[1] Headwaters Inc and Axens form Direct Coal Liquefaction Alliance. Green Car Congress.
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alliance.html2010.
[2] Amoco, Bechtel. Direct Coal Liquefaction Baseline Design and System Analysis Contract No.
DEAC22 90PC89857, Quarterly Report July - September 1992. Pittsburg, Pennsylvania1992.
[3] Amoco, Bechtel. Direct Coal Liquefaction Baseline Design and System Analysis Contract No.
DEAC22 90PC89857, Quarterly Report October - December 1992. Pittsburgh, Pennsylvania1992.
[4] SRI. Highly Dispersed Catalysts for Coal Liquefaction, Phase 1 Final Report 22 March 1995, Contract
No. DE-AC22-91PC91039. Menlo Park, California: SRI International; 1995.
[5] Gary JH, Handwerk GE, Kaiser MJ. Petroleum Refining: Technology and Economics. Fifth ed: CRC
Press; 2007.
[6] Carnegie Mellon University’s Integrated Environmental Control Model (IECM).
http://www.cmu.edu/epp/iecm/index.html.