Ammonia and Downstream Commodities (Urea, Melamine) Order Now : (paperback) → https://amz.run/5A69 The “Handbook for Chemical Engineers and Entrepreneurs” is part of Chemiprobe project that aims to visualize the chemical value chain and turn chemical engineers into «chempreneurs» pursuing clear opportunities in commodities and fine chemicals. https://www.chemiprobe.com

1. This handbook is invaluable
to unfold the chemical value
chain in case you were a
process designing chemical
engineer, or an entrepreneur
pursuing an opportunity in
the chemical market.
Hint : chemical price
analysis requires
comprehensive
understanding of the
production process,
precursors and products
along the value chain.
The “Handbook for Chemical Engineers and
Entrepreneurs” is part of Chemiprobe project that aims to
visualize the chemical value chain and turn chemical
engineers into «chempreneurs» pursuing clear
opportunities in commodities and fine chemicals.
Order Now : (paperback) → https://amz.run/5A69
https://www.chemiprobe.com

2. How To Use This Handbook
This handbook does not requires you to start at the top of
the table of contents and linearly work your way through
to the end; although that may be essential to gain
perspective about commodity chemicals including
petrochemicals, inorganics, and bio-refinery chemicals.
The chemical finder can be used to find a specific
chemical, very much like most indexes in which chemicals
are listed in alphabetical order. On the other hand, the
table of contents lists chemicals with reference to position
along the chemical value chain that is further illustrated
using diagrams. For each chemical in this handbook, you
will find :
- common name, synonyms, chemical structure
- phrases describing appearance and odor (25 °C , atm)
- relative density, melting point, and boiling point
- safety diamond (NFPA 704 for additional notes)
- applications, submarkets, color code
- industrial synthetic route (reaction)
- process description and simplified flow diagrams
commodity chemical production
direct use (no reaction)
formulation and mixing use (no reaction)
fuel, energy , flue gas treatment , heat transfer fluids
plastics and resins
synthetic rubber
polymeric foam , ploymeric fiber
fine chemical synthesis (general)
fine chemical synthesis (pharmaceuticals)
fine chemical synthesis (agrochemicals-pesticides)
production (agrochemicals-fertilizer)

3. Process Description
Production is based on catalytic reaction of hydrogen and
nitrogen over heterogeneous catalyst composed of iron oxides.
The raw material is hydrogen that is often obtained by steam
reforming, nitrogen is mixed with the feed. The mixed feed is
heated inside reformer packed tubes in which ammonia is
formed. Optimum temperature range (500 ºC – 600 ºC) and
pressure in the range of (20 bar – 25 bar).
After leaving the reformer, the effluent is further cooled
through steam generators, heat exchangers, and industrial
refrigerators reaching temperature range (0 ºC – -20 ºC), and
sent to phase separator, the liquid phase containing liquified
ammonia is recovered, the vapor phase containing oxygen and
nitrogen is recycled. Usually, nitrogen is obtained by
introducing air (78% nitrogen) to the reformer, thus ammonia
plant is combined with steam reformer to directly produce
ammonia from hydrogen.
common name ammonia
Appearance 25 °C , atm
colorless toxic gas
pungent unpleasant odor
Relative Density 0.60 * (AIR = 1)
Melting Point - 078
Boiling Point - 033
Flash Point - 132
Synonyms --
intermediate organo-nitrogen derivatives
intermediate inorganic derivatives
alternative fuel fuel cell

4. The term “blue ammonia” indicates that hydrogen -used in
ammonia production- is produced form steam reformer plant
that captures and stores carbon dioxide byproduct, thus
implementing a net carbon approach. The term “green
ammonia” indicates that “green hydrogen” -used in ammonia
production- is produced by utilizing renewable sources for
electrolyzer cell opeartion.

6. Process Description
Production is based on reaction of ammonia and carbon
dioxide forming carbamate intermediate that is further
converted into urea. The raw material is liquified ammonia,
carbon dioxide is compressed and mixed with the feed. The
mixed feed is heated inside vertical reactor in which carbamate
intermediate is formed and further converted into aqueous
urea. Optimum temperature range (180 ºC – 200 ºC) and
pressure in the range of (90 bar – 200 bar). Higher (ammonia-
carbon dioxide) ratios favor high yields of aqueous urea.
After leaving the reactor, the effluent is depressurized and sent
to decomposer in which unreacted carbamate intermediate is
heated and decomposed into ammonia and carbon. The
decomposed effluent is sent to phase separator, the vapor
phase containing excess ammonia and traces of carbon dioxide
is scrubbed with water thus carbon dioxide is recycled to the
reactor in the form of aqueous ammonium carbamate, while
excess ammonia is compressed and recycled. The liquid phase
containing aqueous urea is sent to vaporizer followed by
crystallization stages to recover product.
common name urea
Appearance 25 °C , atm
white crystalline solid
faint ammonia odor
Relative Density 1.32 * (H2O = 1)
Melting Point - 135
Boiling Point - 135
Flash Point - 0--
Synonyms carbamide
intermediate melamine
urea resins adhesives , polymeric foam
urea-ammonium-nitrate agrochemicals - fertilizers

7. Upon demand, excess ammonia is neutralized with an acid
such as nitric acid to produce ammonium nitrates instead of
recycle, thus urea plant is combined with ammonium fertilizer
plant producing urea-ammonium-nitrates.

9. Process Description
Production is based on catalytic reaction of urea over
heterogenous catalyst composed of alumina-silica. The raw
material is urea that is heated and vaporized. The process is
carried continuously. The reaction is carried out inside packed
bed reactor or fluidized bed reactor by using pure ammonia as
fluidizing gas. Optimum temperature range (380 ºC – 400 ºC)
and pressure in the range of (8 bar –10 bar).
After leaving the reactor, the gaseous effluent is quenched
with water, thus exhaust gas containing carbon dioxide and
ammonia is sent to treatment unit or recycled to the reactor as
fluidizing gas. The semi liquid phase containing melamine and
water is further cooled and sent to phase separator, in which
traces of ammonia vapor are vented, then the effluent is sent to
crystallizer to recover the crude product that is further
processed through dryers.
common name melamine
Appearance 25 °C , atm
white crystalline solid
-- -- odorless
Relative Density 1.60 * (H2O = 1)
Melting Point - 345
Boiling Point - 345
Flash Point - 0--
Synonyms 1,3,5-triazine-2,4,6-triamine
melamine resins plastics
fire resistant additives polymer additives

11. Alternative Process : Thermal Reaction
Production is based on thermal reaction of urea. The raw
material is urea that is heated and mixed with ammonia. The
process is carried continuously. The reaction is carried out
inside column reactor by using initial charge of molten
melamine-urea mixture as solvent. Optimum temperature
range (380 ºC – 450 ºC) and pressure in the range of (70 bar –
80 bar). After leaving the reactor, the effluent is depressurized
and quenched with water, exhaust gas containing carbon
dioxide and ammonia is sent to treatment unit or utilized in
urea plant, thus melamine plants are combined with urea
plants. The semi liquid phase containing melamine and water
is further stripped with steam to remove traces of ammonia,
then the effluent is sent to crystallizer to recover the crude
product that is further processed through dryers.