Notes on the very commencement of the research and development in the area of noncatalytic gas-solid reaction systems at the ICPF Prague. Parties involved in the course of time: M. Hartman, K. Svoboda, O. Trnka, V. Veselý, M. Pohořelý, M. Čárský, J. Pata, J. Kocurek and others. Batch ractor.
Parties involved in the course of time:
M. Hartman, K. Svoboda, O. Trnka, V. Veselý,
M. Pohořelý, M. Čárský, J. Pata, J. Kocurek and others.
Plug flow reactor
Mixed flow reactor
Each one of us tends to construct his own biased model of reality by highlighting some experience (significant) and neglecting other (irrelevant).
Combustion:C(s) + O2(g) CO2(g)
Gasification:C(s) + H2O(g) CO(g) + H2(g)
SO2-removal:CaO(s) + SO2(g) + 0.5 O2 CaSO4(s),
incineration of solid wastes, calcination, H2S-removal, etc., etc.
· Mass transfer between single particles and gas stream.
· Diffusion of gaseous components through a solid matrix (pores)
and solid state diffusion.
· Sorption and chemical reaction.
· Heat transfer.
· Textural changes brought about by the chemical reaction
The most striking difference(s):
- NGSRs are rather more intricate due to the direct participation
of the solid in the reaction.
- The texture of the solid changes as the reaction goes on.
- NGSR systems are inherently transient (of unsteady nature).
- Analysis involves an additional dimension-time.
is governed by several interrelated quantities:
- the flow pattern and contacting gas with solid
- kinetics: chemical reaction,
(heat & mass transfer).
Thermodynamics and mechanical design must also be considered.
Which quantities govern reactor behavior/performance.
What’s needed to relate output
to input of a reactor.
Reliability of the reactor prediction and design.
The pragmatic approach in chemical reaction engineering:
- abstract from the complexity of the real system and to substitute
a more or less idealized situation / model
- that is more amenable to analysis.
The Exxon model fluid cracking unit
Six broad types of contactors:
1. Packed (fixed, static) beds (PB).
2. Bubbling fluidized beds (BFB).
3. Turbulent fluidized beds (TFB).
4. Circulating fluidized beds (CFB).
5. Moving beds (MB).
6. Rotating kilns (RK).
Big bubble bed
Advantages of FB
- The rapid mixing of solids leads to near isothermal conditions.
- The liquidlike flow of particles.
- Heat and mass transfer rates are high.
Disadvantages of FB
- Limited understanding of the complex physics of fluidization.
- The erosion, entrainment of fines, bypassing.
Commercial blast furnace
As needed steps in the developed new technology of
terephthalic acid (TA).
In the 1960s, early 1970s.
400oC, 1 MPa
2 C6H5COOK(s) C6H4(COOK)2(s) + C6H6(g)
Cd, Zn, CO2
m.p. 425 oC
m.p. > 550 oC
(F. Kaštánek, A. Zemek, J. Kratochvíl, et al.)
- performed in a tubular reactor (MB) with a mixer,
- plagued with mechanical problems,
- the formation of unwanted humines,
- a peculiarity: always starts at the centre of pellets
and spreads outwards,
- originated as a wanted operation in the TA process.
The sublimation and thermal decomposition:
C6H4(COOH)2(g) + 2 NH3(g)
(J. (P.) Vítovec, J. Smolík, J. Kugler, A. Haklová, Z. Říha, and others)
- has to be accompanied by a condensation / solidificationstep
- the inert bed material: corundum particles (exhibit a high thermal
- a sublimation – condensation pilot plant was designed
- the excellent outcome of R & D, a number offoreign
- very efficient process also for other materials
(e.g., for phthalanhydride and anthraquinone),
- later on, the activities expanded greatly in different
In the Department of Chemical Reactors with F. Kaštánek
and J. Čermák as the then Heads.
Period of time
From the early 1970s till the 1980s.
(J.Beránek, V. Havlín, L. Foršt, B. Čech, V. Malaník,
H. Kohoutová, J. Pata, V. Veselý, M. Čárský,
J. Kocurek, and many others)
The conceptual design,
construction and operation
of a prototype of the
Status and characteristics
- The application – oriented project.
- External, strong, influential partners: VŠB Ostrava,
SONP Kladno, strojírny Tlmače.
- Financing from the State plan of science & engineering
development (SP RVT).
with SO2 removal
The attractive features of the FBC
- The relatively low operating temperature (800 – 950oC).
- Low-value fuels (coals) can be burned.
- SO2 produced during combustion may be
captured by adding limestone or dolomite into the bed.
Final outcome of the project
-A smaller commercial / production boiler with all
accessories erected at Trmice (N. Bohemia) and tested.
- The operational principles found feasible, but the machinery
assessed as overly complicated.
- Further development discontinued.
- The work commenced as a tiny appendix to the big
„Fluidized combustion with desulfurization“ project (J. Beránek).
- On a small scale only: with a laboratory or bench-scale
Harmful gaseous pollutants of interest
SO2(SO3), H2S, COS, NOx.
Solid reactants (sorbents)
CaO, MgO, CaO.MgO, Na2CO3 (active soda).
Precursors: - a host of limestones and dolomites of different
origin from Bohemia & Moravia,
- (waste) magnesite (Slovakia),
- hydrated lime (Ca(OH)2),
- calcareous muds,
The conditions of reaction (sorption)
Under ambient pressure, mostly at high temperature: 700 – 1000oC.
In an oxidizing environment (SO2 from flue gas), in a reducing
one (H2S from fuel gas).
Experimental facilities developed and employed
- A high-temperature, differential, fixed-bed reactor for
the kinetic studies.
- A high-temperature, fluidized-bed, bench-scale unit for
the reactor performance studies: the batch, continuous,
or semi-cont. mode of operation.
Crucial problems: low rate feeding of solids,
heat resistant materials.
- Cold, transparent (glass) fluidization columns for the
hydrodynamic studies with different fluidized beds.
Pneumatic slide feeder
Laboratory, fluidized, high
Topics / subjects investigated
·The thermodynamic constraints on some reactions, e.g.,
sorption of SO2 by MgO, that of H2S / COS by CaO
(the competition with CO2 in fuel gas).
·The changes (often dramatic) in sorbent texture caused
by the „cleaning“ reaction; with the aid of P. Schneider,
D. Tomanová, O. Šolcová et al.; the sintering of nascent
·The kinetics studies and kin. modeling:
- the reduction in porosity,
- intraparticle transport,
- chemical reaction.
·The model equations (PDE) are inherently „stiff“ :
Solution of this and other computational problems
developed by O. Trnka (then in the Computing Center).
Amongst The 100 Most Cited Articles in AIChE Journal History
Thermal decompositions in the fixed and fluidized bed
· Hydronium jarosite, H3OFe33+(SO4)2(OH)6; in the elimination
of iron from technol. polymetallic solutions.
·Dehydratation of sodium carbonate hydrates:
Na2CO3 . 10 H2O, Na2CO3 . H2O; to produce effective
sorbents, e.g., for NOx. A joint project with E. Erdös.
·Decomposition kinetics of Ca, Mg-hydroxides and the
sintering of the oxides, to achieve high reactivity and special
textural properties of the oxides; with the aid of
O. Šolcová and H. Součková et al.
Combustion of liquid fuels in the fluidized bed
· Formation of NOx in FBC: the conversion of the fuel-bound
nitrogen to NO2 and NO.
· Disposal of waste oils in a rolling mill in Chomutov.
Analysis of the pressure fluctuations within the FB
· An efficient means of monitoring the FB behavior,
particularly at elevated temperature.
· Started with the participation of J. Drahoš, K. Selucký,
and M. Punčochář.
The authors of this exposé ( M. Hartman and O. Trnka)
wish to appreciate the unflagging attention and interest
shown by the audience.