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Semco Maritime
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Selective Catalytic Reduction (SCR)

Shifting priorities towards decarbonization

NOx is a global environmental problem as the emission of Nitrogen oxide (NOx) causes acid rain, smog, eutrophication, and the formation of ground-level ozone, thus intensifying the effects of global warming.

Reducing NOx emissions:

Selective Catalytic Reduction (SCR) is a technology used to reduce the levels of nitrogen oxides (NOx) in exhaust gases from internal combustion engines, particularly in diesel engines. The process involves injecting a reductant, usually a solution of urea (also known as Diesel Exhaust Fluid or DEF), into the exhaust stream.

The process significantly reduces the amount of NOx emitted from the engine, helping to meet stringent environmental regulations.

Since nitrogen makes up about 79% of the Earth's atmosphere, the transformation of NOx into nitrogen and water effectively reduces the emission of harmful pollutants without introducing new harmful substances into the environment

How SCR systems work:

  1. Injection of urea solution: The urea solution is injected into the exhaust gas stream. The heat from the exhaust gas converts the urea into ammonia (NH₃) and carbon dioxide (CO₂).

  2. Mixing and reaction: The exhaust gas, now containing ammonia, passes through a catalyst. This catalyst is usually made of materials such as titanium oxide (TiO₂), vanadium (V₂O₅), or other suitable catalytic materials.

  3. Reduction reaction: In the presence of the catalyst, the ammonia reacts with the nitrogen oxides (NOx) in the exhaust gas. This chemical reaction converts the NOx into nitrogen (N₂) and water (H₂O), both of which are harmless. The overall reaction can be simplified as follows:
    1. 4NO + 4NH₃ + O₂ → 4N₂ + 6H₂O
    2. 6NO₂ + 8NH₃ → 7N₂ + 12H₂O

  4. Emission of clean gas: The resulting mixture, now containing harmless nitrogen and water vapor, is emitted from the exhaust system.

Strategic advantages:

Reduction in NOx emissions: Capable of reducing annual NOx emissions by up to 95%.

Cost efficiency: Helps in calculating total costs from emissions offsetting and tax implications, leading to significant savings.

Enhanced asset value: Increases the operational lifespan and efficiency of the rig, making it a more valuable asset in environmentally regulated areas.

Consider this before choosing an SCR system:

Implementing an SCR system onboard rigs or vessels provides the triple benefit of reducing emissions, ensuring compliance, and improving operational efficiency, making it a valuable investment for sustainable and cost-effective operations. 

However, the below points are worth considering:

The space issue

Where to place the urea tank? 

Placing the urea tank in a readily accessible location facilitates easier refilling and maintenance. Routine inspection, refilling, and servicing of the urea tank are necessary to ensure continuous operation of the SCR system.

Rigs and vessels often have limited space available for equipment installation. Careful consideration of the urea tank's placement ensures efficient utilization of available space while minimizing interference with other onboard systems or operations

Therefore, we begin our projects by 3D scanning your asset to make sure that we have no nasty surprises - and to make sure that we find the optimal location for the enormous urea tank that is part of the SCR system.

Do the math

Calculations on back pressure:

Back pressure ensures that essential equipment operates within the design limits. Without proper back pressure, your systems can experience issues like cavitation, overheating, or mechanical failure, which can lead to costly repairs and downtime.

Proper back pressure management is essential for ensuring that the SCR system operates effectively, enabling compliance with emissions regulations.

These calculations are relevant for SCR systems to optimize performance, ensure compliance with emissions regulations, protect engine integrity, and facilitate effective system integration.

Go for EPCI solutions

Consider the benefits of an EPCI approach...

Choosing an EPCI supplier with offshore installation expertise provides numerous benefits, including regulatory compliance, seamless integration, enhanced safety, effective project management, and optimized performance, making it a good choice when deciding on an SCR system for offshore rigs and vessels.

By choosing an EPCI solution, you benefit from tailor-made, high-performance systems that deliver significant emission reductions while ensuring compliance, cost-efficiency, and operational excellence. 

Choose your EPCI partner based on their level of commitment to excellence, environmental responsibility, and SAFETY. Make sure to check their references within retrofits and modification projects!

Creating change and leading by example

We are committed to leading CHANGE by implementing innovative solutions that meet local demands and enhance operational efficiency and sustainability.

Contact us today:

Simon Wall

Sales & Business Development Director

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Semco Maritime AS
Hanøytangen 130
5310 Hauglandshella
Norway

Nicolaj Bjerre

Operation Manager, Rig & Offshore

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Semco Maritime Inc.
4321 Kingwood Dr. Suite 572
Kingwood, TX 77339
USA