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highlight the revamp capabilities of Stamicarbon, as much in terms of developing the optimum process scheme as in terms of troubleshooting and elegantly solving capacity limitations.

acity.

wanted interconnections for the minimum of investments. Stamicarbon was asked to come up with options for realizing that aspiration, making maximum use of the existing equipment or – if needed – reusing second-hand HP equipment available from elsewhere within the company. Stamicarbon presented two options, the first based on the customer’s initial revamp ideas, the second on a custom adaptation of Stamicarbon’s EVOLVE FINISHING™ UAN Design. The benefits of the EVOLVE FINISHING™ UAN Design (the second option) over the “conventional” revamp (the first option) were so evident that no further discussion was needed. The project, option 2, is currently being executed. This paper shows that even older plants can be brought up to date for limited investment.

f publications available, but little data for validation

melt feed to finishing: 75-125 kg/h (165-275 lb/h) What can we do about this ? •Reduction of the ammonia emissions via scrubber technologies •More specifically we will see scrubbing with aqueous acid solutions is used broadly

rojects: Reference projects (Conventional) 

ralChem co-operates in joint research with Moscow State University and Stamicarbon. UralChem is to revamp the urea plant of its subsidiary in Perm, the operating company Mineral Fertilisers OJSC (PMF) Perm

d by Stamicarbon and IPCOS combines the benefits from MPC and Nonlinear optimization of Urea plants into one solution.

and the 1st stage evaporator heater, the steam consumption can be lowered considerably. For instance, for a urea melt plant with prilling as finishing technique, the turbine extraction steam consumption can be lowered from 868 kgsteam/tonproduct to 558 kgsteam/tonproduct. The design challenges for the critical equipment in this low energy concept with respect to corrosion and sizing have been addressed and solved.

n with Stamicarbon’s fluidized-bed urea granulation technology. By SpiralMist quenching and accelerating the granulation exhaust gas through MicroMist™ Venturi (MMV) tubes, particulate emissions as low as 10 mg/Nm3 can be achieved. An additional polishing Star Wet Electrostatic Precipitator (Star WESP) can further reduce particulate emissions to as low as 5 mg/Nm3. This paper discloses the fascinating story of the conceptual development, pilot testing, detailed design and fabrication of the Stamicarbon-Envirocare MMV scrubbers for two new grass-root urea granulation plants in the USA.

ine for this discussion by focusing on three key questions: Which acid should preferably be used? Which outlet for the resulting ammonium salt is preferred? Should the dust and NH3 scrubbing be combined in one scrubber?  

possible ways to eliminate ammonia emissions from continuous emission sources in the urea melt synthesis and purification sections, as well as from discontinuous ammonia emissions during upset conditions. Stamicarbon flare designs and recent innovations with regards to the thermal treatment of ammonia are discussed. Guidelines for a safe design of flares and for a so called “ADVANCE DESIGNTM Thermal Treatment” system are given. The paper highlights and explains the catalytic and non-catalytic combustion technologies offered and elaborates on the pros and cons of these technologies. It is shown that for eliminating continuous ammonia emissions during normal operation, the ADVANCE DESIGNTM Thermal Treatment system offered by Stamicarbon has significant advantages in comparison with flaring. Not only is the environmental impact significantly less; also both investment and operating costs are much lower.

ily meet the emission levels prescribed by law. Because it recovers waste water for re-use and produces ammonium salts that can be processed and sold, this technology is environmentally friendly in comparison with other cleaning methods that can produce additional emissions (for example, NOx and CO2 in the case of flaring). It has a CAPEX advantage because it requires less infrastructure investment than do other technologies. It requires neither the catalyst needed in SCR (selective catalytic reduction) nor the high operating temperatures and costly construction materials associated with incineration. Last but not least, wet scrubbing is simple to operate and it does not entail the extra safety precautions needed with, for example, flaring.

or transporting their product, plant owners are low.

a emission reduction in the urea finishing section • Key take-aways  

their absence, the current WHO Air Quality Guidelines or comparable guidelines set by other internationally recognized bodies. So there are no globally-applicable emission limits; they differ region by region according to standards set by the local authorities. For the licensor this means that every new project, whether grassroots or revamp, needs a tailor-made approach in close co-operation with the engineering contractor, owner of the facility and local authorities. 

o the atmosphere can environmentally wise be benchmarked against the alternatives of incineration, heating and combustion technologies. The paper explains Stamicarbon’s objections regarding the use of flare systems as environmental mitigation strategy in the urea melt plant and clarifies the most environmental and economical sensible solution available in Stamicarbon’s technology portfolio: the thermal treatment and catalytic DeNOX. An example case of a world scale urea plant is used for quantification and the outcome of the paper reveals Stamicarbon’s bridge that connects today to tomorrow.

gas (GHG) emissions is estimated to be less than 1%, great efforts have been made to understand what the main sources are and in what proportion, so that appropriate mitigation measures can be taken. As for any other chemical, GHG emissions attributable to urea are associated with its life cycle, from the extraction of raw materials to its application and disposal. Since ammonia and carbon dioxide are the raw materials for producing urea, the impact of an ammonia plant is an important consideration when assessing the carbon footprint of urea. This paper focuses on carbon dioxide and nitrous oxide emissions related to ammonia and urea production, and discusses available measures to reduce direct and indirect emissions. Some urea applications such as urea deep placement (UDP) and diesel exhaust fluid (DEF) are also briefly discussed, to illustrate the potential of urea applications to reduce GHG emissions.

an be solved in two different ways, either with an in–line and/or with an end-of-pipe solution. The combination of the equilibrium reaction and the presence of inerts make an in-line solution not feasible. Therefore end-of-pipe solutions to eliminate ammonia emissions in both urea melt and finishing plants are still needed to obtain a green and environmentally sustainable process. This paper covers the different available end-of-pipe solutions such as absorbers (including emergency absorber), acidic scrubbers and flares. These options have a wide range of operating windows for further optimization and achieving optimum environmental performance. Flaring reduces the ammonia emission by converting the ammonia into carbon dioxide and nitrogen oxides (NOx). Therefore, the environmental impact evaluation - after implementation of the new end-of-pipe solution - needs to be reviewed, especially when applying continuous emission flare because the environmental impact of these new type emissions are not more tolerable than ammonia emission. Stamicarbon believes that a green urea process combines optimum process conditions with a good choice of end-of-pipe solutions. The available alternatives for end-of-pipe solutions target an optimum “Triple P” balance, i.e. the balancing between financial-economical achievements (profit), environmental impact (planet) and public acceptance (people).

d upon natural gas produce a ratio of 1.3 to 1.5 carbon dioxide to ammonia of which about 18% is in the form of flue-gas. •Ammonia plants based upon coal gasification produce a ratio of 2.7 to 2.8 ton per ton of ammonia