Journal of Power and Energy Engineering, 2015, 3, 348-355
Published Online April 2015 in SciRes. http://www.scirp.org/journal/jpee
How to cite this paper: Petters, S. and Tse, K. (2015) Clean Coal & High Carbon Efficiency Energy Engineering. Journal of
Power and Energy Engineering, 3, 348-355. http://dx.doi.org/10.4236/jpee.2015.34047
Clean Coal & High Carbon Efficiency Energy
Stefan Petters1,2, Kalvin Tse2
1BoD of guo-Business Development Consult Vienna, Austria & Bestrong International Ltd, Hong Kong, China
2R & D Bestrong International Ltd, Hong Kong, China
Received January 2015
Today we live in a world of Hydrocarbon Energy Carriers, where Carbon is always used as a Carri-
er for Hydrogen 1) Biomass (CH1.44O0.66 or C6H12O6); 2) Natural Gas [NG] (CH4); 3) Water Gas
[C+H2O]; 4) Gasoline (C6H12, C7H18, C8H18, etc.); 5) Kerosene (C17H36, C18H38, C19H40, C20H42, C21H44,
C22H46, etc.) and ; 6) Crude Oil. The Carbon aggregates are all storable and have worthwhile, logis-
tically manageable energy densities. But whenever recovering Energy from the Carbon molarities,
CO2 gets emitted into the atmosphere, while separate use of Hydrogen Energy contents carried by
the Carbon moieties would just generate water vapor. Hydrogen is also the most important inter-
mediary in Refineries, hydrogenating lower grade Hydrocarbons into higher potencies, or for re-
moving Sulfur by the formation of Hydrogen Sulfur, that can be dissociated after its segregation
from the Hydrocarbon products. But most of the internal Hydrogen yields in Refineries today is
used for onsite production of Ammonia as a basis for Energy fertilizers in high performance agri-
culture. Because Hydrogen is awkward to store and transport, most of it is currently used captive
within large size centralized plants as a reactant for producing Hydrocarbon energy carriers, us-
ing the Carbon as a carrier for the Hydrogen moieties, to then be distributed over big enough areas
for consumption of the such large scale plants’ volumes. With recently proven achievements of
Hydrogen production from excess Wind & Solar Power by electrolysis, Hydrogen could become
available in abundant quantities, to be distributed locally within the coverage area of the trans-
mission grid such Wind & Solar installations are feeding into. In combination with Carbon as a
reactant such abundant Hydrogen could also be synthesized into Hydrocarbon Energy Carriers
and substitute fossil commodities.
Atmospheric Carbon, Carbon Efficiency, Carbon Metabolism, Carbon Re-Use, Chemical Energy
Content, Controlled Microbial Composting, Energy Carriers, Fossil Substitute Commodities,
Intermediaries, Heating Value, Hybrid Power Plant, Hydrocarbon, Hydrogen, Organic Waste
Valori z ati on , Photosynthesis, Productivity, Refineries
Unfortunately Energy Engineering had been driven mostly by sectorial views. 1) Humans tend to feel more
S. Petters, K. Tse
comfortable when segregating issues into isolated segments. So solutions to problems found, often ignored im-
portant nexus’. 2) And if we look at mankind’s problem solving practice, most often we find the “more of the
same” as well as the “bigger the better” models. 3) As long as something plentifully available and inexpensive
works, we tend to use it wastefully. 4) Anything not having any obvious value predominantly is left aside and
disregarded. 5) Last but not least, in case of adverse knock-on effects of a developed practice, abatement strate-
gies prevail over root-cause mitigation approaches. In the name of Productivity Energy Technologies had been
focusing on ever increasing grade of fuels, rated by the heating value as a measure for the Chemical Energy
content of it. Isn’t it symptomatic for our mind sets, that it’s called “Heating Value”! Obsession for quickest and
supposedly cheapest solutions drove most conventional Energy Engineering simply by secondary energy yield
objectives. Since the invention of steam engines the process chain for fuel use is always its combustion to heat
for transformation into mechanical work. Today’s Combined Heat and Power standard brags with the use of
“Wa st e-Heat” being just transformation losses in reality.
But the biggest show-stopper of combustion in large scale is that thermo-chemical processes always need
continuous operating conditions, irrespective of whether the output heat can be fully consumed or not. And what
we don’t use, we lose.
Refineries, also thermo-chemical plants, of course need continuous operations as well, but do not destroy the
feedstock’s Chemical Energy content. They transform it into higher grade Hydrocarbon Energy Carriers, whe-
reas waste heat in the process chain can often be used onsite to actuate intended chemical reactions, helping to
achieve good Output per Input Efficiencies. Unfortunately these achievements have so far almost only been ap-
plied for liquid or gaseous fossil primary Energy Carriers and in very few examples only for some high grade
coal solid fuel applications, also being fossil energy.
Could it be that the future is obviously already among us, just not dissipated, interpreted and applied in the
most favorable ways for us?
2. Questions on Best Available Technologies
2.1. Energy Intensity and Carbon Efficiency
According to Lawrence Livermore National Laboratory [US] the total 2013 Energy consumption of the USA
was 40% efficient only, relative to the primary energy used, whereof 82% were from non-ambient carbonaceous
energy carriers (60% were just wasted).
Projections for 2025 promise an efficiency improvement of 12.5%—assuming an increase of carbonaceous
energy carriers of 8.6% (so Green House Gas Emissions for wasted energy will actually grow proportionally
with the increase in consumption).
It would however not be unusual for the USA, if things came differently—the re is very interesting develop-
ments going on, contradictory to the projections of the Department of Energy, supported by the Department of
Defense—namely in the field of Bio-Refineries from MSW residues, going for Fossil substitute Commodities.
2.2. Bio-Refinery Technologies
4 years ago the term Bio-Refinery enjoyed 150 citations in scientific papers. Around that time several groups
involved in abundant organic matter valorization had demonstrated full feasibility of biomass or organic waste
decomposition into energy rich gases as well as chemical synthesis from their Hydrogen and Carbon monoxide
While in Europe only Biomass conversion into Substitute Natural Gas or CHP electricity was supported into
Lighthouse project implementations , the US Department of Defense supported a first time implementation
for waste valorization into jet-fuels. Because of conditions precedent in the USA, where there is no market for
Refuse Derived Fuels [RDF] due to cheap enough availability of Natural Gas, not needing flue gas clean-up,
RDF has no value and energy is considered cheap enough to use auxiliary energy for transformation processes.
On that basis demonstration looked economic enough for Hong Kong airline Cathey Pacific to invest into a
roll-out of a RDF to jet-fuel project!
3. China’s Growth Strategy Model
China’s fast and flexible capacity building capabilities facilitated remarkable poverty reduction over the last 20
S. Petters, K. Tse
years. But in this historic model China had been building on a Quantitative Growth Strategy model . It works
by crowding out competition through scale of economy advantages from shedding complexities for highest
possible segmental efficiencies and maximizing demand by advertising customer expectations you can fulfill for
the best scale of economy for each product.
A Qualitative Growth Strategy model relies upon building up capabilities followed by allocation of markets in
need for it . By developing the best fit for every application it creates additional added value, avoiding waste
redundancies or adverse consequential remedies under the use of available synergies.
3.1. Coal Gas Projects Seen in China
Currently used Technology in Coal Gas seems to run at fuel to steam ratios of ~4, which at an average of 85%
Carbon content in the coal processed, would represent a steam to Carbon ratio of almost 5 . That is about 3
times the theoretic technical need—can this be the right Technology for coal rich geological areas, usually not
blessed with a lot of water?
3.2. Carbon Efficiency Increase Springboards
China has impressively demonstrated to cumulate experience towards highly competitive supply capability
for Solar or Wind generation plants and over the last 2 years led the world in new installations, ranking
global number one now in installed capacity.
Companies like Dragon Power Industries have been very successful in developing renewable electricity by
energy recovery plants from straw biomass, after coming up with a standardized solution of awkward logis-
tics’ challenges related to straw.
Over the last 5 years we have seen lots of progress in municipal waste water treatment capacities. Unfortu-
nately however add-on solutions for sewage sludge discharge, requiring inertization and minimization of fi-
nal sink disposal space are still lacking behind.
Our testimonial of scientific collaboration between the Austrian University sector and Chinese Academy of
Science highly admires the in depth investigations and knowledge of Chinese Scientists on Coal as a solid
fuel. While there is a lot of remarkable expertise in China, how to upgrade coal prior to its use, the Austria
has been peering the in clean use of poor carbonaceous fuels for the past 10 years already  (Canada, Swe-
den and France all came to license it in).
Waste has become an expensive burden to China’s urban citizens. Incineration, widely considered being
Best Available Technology is financially not self-sufficient and even less economic, wherever its logistics
involve an informal sector (as being the case in China). They pick anything that is valuable as a direct re-
cyclable, reusable or Refuse Derived Fuel (Energy Recovery) item and leave the waste sector just the puta-
tive invaluable residues .
3.3. Innov at ion
There may be many business people who make or administrators who take money out of others, but fail to add
new value to society. The world has cumulated so much menace to life on our planet, because there are too few
fearless people, having vision, passion persistence and open minds to learn from each other how to implement or
execute economically self-sufficient solutions, that can improve or ease peoples’ lives = Innovation.
China working on multiyear planning horizons on the other hand could actually provide uniquely suitable
cycle time conditions precedent for Innovation based Qualitative Growth.
4. Reducing China’s Carbon Intensity
At the first IAEE-Asia Conference held in China, 2014, opening remarks China’s political demand for reducing
Energy Intensity and an increase of Carbon Efficiency was clearly stated . Of course an Energy mix relying
more than 2/3 on coal, opens a lot of perspectives for Carbon Efficiency improvements by either reducing
Energy Intensity or replacing coal by Natural Gas, particularly in conjunction with New Renewable Energy
back-up requirements. There are enough concepts in place at higher per capita income countries that may tempt
China to import. But unfortunately none of these fulfill the most important condition precedent of Sustainabili-
ty—namely: “financial self-sufficiency under arms’ length market price business conditions” —Not perceived to
S. Petters, K. Tse
be fulfilled by today’s New Energy sectors, whether it was renewable or unconventional gas! In all these sectors
achievements have been reached at the expense of tax-payers, consumers or investors.
Therefore delivery of China’s political demand will require Innovation. For that we would suggest an integra-
tion of proven Technology elements into new combinations of hybrid Energy Systems.
4.1. Retaining Energy in Storable Aggregates
Decentralized configurations of waste heat induced Energy generation can enjoy economic opportunities from
district heating or cooling, as often demonstrated in so called Waste-to-Energy configurations (where secondary
resource feedstock’s Energy is just scantily recovered).
1) System Effectiveness of solid fuel fed plants could be significantly uplifted if direct combustion = stored
energy release into secondary energy and CO2—was replaced by gasification = retaining bigger part of stored
chemical energy in transformed storable moieties—and using only unconverted fractions for auto-thermal
transformation energy alimentation. This would yield following advantages:
a) Any fuel poisons could be separated from the non combusted anoxic hydrocarbon product gas mix in forms
that even allow elementary recoveries.
b) Downstream use of the product gas, volatilized from the solid fuel feedstock can be spread over several
usage paths and/or allotted independently from the feedstock input cycle, according to final output demand time
c) Excess product gas output from solid fuel input represents unconsumed Chemical Energy and can be used
in Chemical Synthesis production of Fossil substitute Commodities.
2) Combining above described Solid Fuel Refinery with excess New Renewable Energy Power to Gas elec-
trolysis of Hydrogen allows :
a) sharing temporary storage facilities as well as the hardware for utility scale Hydrogen Fuel Cell back-up
electricity generation for New Renewable Energy grid with waste-heat use within district heating or cooling.
b) extension of the product portfolio spectrum for Chemical Synthesis of fertilizer, fuels and/or polymers.
c) preparing Hydrogen Mobility distributed fuel production, saving long haul transportation of Hydrogen .
4.2. Refining Ambient versus Fossil Carbon
As already outlined in the Abstract, biomass actually represents a Hydrogen rich solid carbonaceous fuel .
Simple combustion for so called Energy Recovery just neglects this uniqueness and just follows traditions of
B iomass actually represents a suitable feedstock for Hydrocarbon transformation refineries. By using it as a
feedstock for chemically synthesizing Fossil substitute Commodities from its decomposition gases we can
achieve Re-Use of ambient Carbon.
This applies equally to any organic waste or residues, whether originating from harvested biomass, fermenta-
tion sludge or fossil derived MSW fractions. All of this represents potential atmospheric Carbon stock if turned
into CO2 by incineration or biological degradation, sometimes even to 23 times as aggressive CH4 emission.
Solid low grade fuel refining has been being developed in Austria over the last 30 years from stationary to fast
internally circulating bed gasification reactors. Today’s state of art has arrived at “Fast Internal Circulating Dual
Fluidized Bed” [FICDFB] gasification proven in a multiyear >7,000 hrs/a operation at Oberwart . Recently
FICDFB Technology was licensed out to Sweden and France for lighthouse projects (of Gothenburg-Gas and
GDF-Suez respectively) .
4.3. Clean Coal Use
Steam-Driven FICDFB Gasification yields two separate gas output streams: a) Flue Gas Stream (12% CO2, 6%
O2, 83% N2) from the combustion chamber, where the char residue of the anoxic, fast pyrolysed (thermo-chem-
ically cleaned) feedstock gets combusted, and b) product gas stream, which includes the typical fuel poisons in
the form of hydrates, e.g. H2S, NH3 or HCl, allowing cleaning by ways of enabling reuse of the same.
The solid fuel transformation into usable energy is here induced by heat from the fast circulating (~50 times/h)
Bed Material (i.e. mineral sand) as a heat transfer medium between the Combustion (oxygenic) and Gasification
(anoxic) chamber. This becomes possible, as unconverted Carbon ends up intermixing into the bed-material and
S. Petters, K. Tse
as schematically shown in Figure 1 moves onward with the sand to the Combustion chamber, where the air
supply, rising the sand back up to the recirculation loop into the Gasification chamber, lights the char up (alike
in a smith oven) and heats the sand during its rise.
The Gasification chamber is a bubbling bed, fluidized by water steam, effecting fast high temperature Pyroly-
sis followed by a steam reforming water shift equilibrium reaction in the free board zone above the bed’s splash
zone, as illustrated in Figure 2.
Figure 1. FICDFB functional scheme.
Figure 2. FICDFB reactor.
S. Petters, K. Tse
One of the merits of this process for thermo-chemical decomposition of solid carbonaceous fuels is its wide
tolerance to varying feedstock qualities and composition. Originally developed as enhancement in sewage
sludge incineration FICDFB can process up to 40% moisture in the feedstock, different materials, as Refuse De-
rived Fuel, Biomass, Coal, sludge of fermentation residues at the same time from parallel feeders at varying po-
sitions of the reactor, as long as the compounded average Lower Heating Value of the solid fuel mix results in
≥10 GJ/ton . A practical application example is illustrated in Table 1 and Figure 3.
4.4. Clean Coal Use
We have seen various initiatives in China to optimize coal quality prior to its use, such as coking plants or dry
While all coal purification efforts seen in China are economically affected by scrape rates, FICDFB can either
process the low grades falling off from such existing purification processes, or save the extra purification step
and use the original coal as is in a clean manner . However, the scales we have commonly seen in Chinese
coal industry, would need to be downsized for FICDFB.
In terms of the water nexus a broader geographic dispersion of capacities over the territory should however be
quite advantageous. In addition FICDFB operates at a Steam to Carbon ratio of 1.8:1, which at a manageable
moisture content of feedstock in the order of 30% ± 33% results in a Steam to Fuel ratio of 1 - 1.4:1 - 1/3 of
what we have seen in China’s large scale coal-gas installations.
4.5. The Economics of Smaller Scales
Of course in mechanical devices like turbines or hydraulic presses, etc. scale may be an advantage. But is it
equally true for chemical reactors? Maybe anything bigger than standard size steel tubes available on the market,
needing to replace industrial volume produced components by special handcraft on site construction, may be
more expensive to build than larger volume factory made series of smaller units.
Coming from industrial mass production, we know well that synchronization of capacities linked into a
process chain is a much stronger key to overall economics than a singular process step’s scale of economy.
Therefore we consider scale much less important than potential economics of synergies between process steps
hybridized into a total system. Flexibility in process chain sequence for mitigation of resource losses often pays
off any additional investments needed for it, in a fraction of time required to amortize the basic system’s in-
4.6. Hybridizing Thermo- & Electro-Chemical H2
Since FICDFB is limited in scalability and therefore best suitable for decentralized local feedstock use, it could
easily be combined with vicinal New Renewable Energy generation back-up measures in the area .
China having its genuine own Coal resources has been internationally pressured to switch coal to Natural Gas
, as thermal power from Natural Gas comes at ~50% the CO2 Emissions than from Coal.
In this example 34% of Echem would be contributed from Ambient Carbon Stock, of which 60% Echem is con-
tributed by the Hydrogen contents of biomass & RDF—resulting in a 54% reduction of accountable Green
House Gas Emissions compared to heat from coal only—Coal could be co-used cleanly at identical fossil emis-
sions as Natural Gas would cause for the same Heating Value, if compounded with ambient Hydrocarbon resi-
China’s Energy Engineering could uplift sustainability standards significantly, if entrepreneurial spirit could be
Table 1. Typical feedstock lower heating values.
Lower Heating Value Type of Feedstock
Lignite or Biomass CN-MSW
GJ/t 20 17 6.5
Ø ≥10 ≥35%wt or ≥41%wt ≤46%wt
S. Petters, K. Tse
Figure 3. Examp le of a mixed fuel MSW & sludge.
enticed to tap on China’s unique positions in New Renewable Energy installations and Carbon refining exper-
tises from coal know how. Hybridization of decentralized electricity generation from Solar and/or Wind energy
with Power to Gas back-up Hydrogen electrolysis and MSW and/or Biomass Carbon refining, leveraged with up
to ⅓ coal, would be an enormous People Planet Profit opportunity. There is a need for 25,000 MSW refining
plants and room for another 50,000 agricultural and industrial organic waste Bio-Refineries in the world. This
could lead to a new industry of similar order of magnitude like global commercial airplane industry, turning at a
building rate of 800 units per year. At such production level the MSW sector alone would give a 30 year task to
such new industry.
Last but not least the proposed hybridization with excess New Renewable Electricity Electrolysis Hydrogen
could overcome the struggles with intermittency without enormous investments into storage solutions. At the
same time it could increase bio-refineries’ chemical synthesis Carbon Re-Use capabilities by ~30%. Changing
the excess production paradigm in Energy Engineering to decentralized hybrid grids, producing secondary
energy from continuous thermo- or bio-chemical processes only on demand and indirectly, would help shave
volatile intermittency of temporarily insufficient New Renewable Production and allow to keep recoverable ex-
ergy from primary or secondary resources in logistically flexible to handle, storable chemical aggregates.
Apart from minimizing yet unresolved storage issues for New Renewable Energy such arrangements would
guarantee higher plant usage rates for all assets installed. At the same time Energy Efficiency losses from idling
back-up operations could be eliminated and thus uplift Carbon Efficiency and reduce Primary Energy Intensity.
Last but not least this model could save having to build incinerators and turn large part of waste remediation cost
into a value adding positive GDP contribution.
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