Project SS (ACE) – Urea IBC system / cleanNOx Urea Skid

cleanNOx Panel Details:

• Stainless Steel cabinet (free standing)

• Dosing pumps with a feed rate of 7.8l/hr (duty/standby)

• Duplex strainer with fine mesh 

• Diverter valve

• Digital pressure switch

• Flow transmitter

Project

The enquiry came from a boiler consultant we had previously worked with on a flue gas treatment plant project (see project DH) which also had a SNCR system installed.

Our client installed a waste heat boiler to provide a heating system to a well-known luxury yacht manufacturer factory.

This enabled them to burn the waste plywood generated within the manufacturing process.

Previous emissions testing showed that higher than anticipated NOx levels were being produced failing the MCPD requirements for NOx emissions of 500mg/m3 @ 6% O2.

The NOx levels were exceeding 670mg/m3 and with the other information received we were able to use our in-house reagent waste calculator to work out approximately how much urea was needed to be dosed which we could then size the appropriate nozzle duty and spray pattern.

Our client provided us with a 3D model of the boiler, and we were able to design the lance to enable us to 

retrofit the lance in an existing 1’’ port on the side of the boiler. This meant that we had to design a lance suitable for the port but allow maximum adjustability for the spray pattern to allow us to fine tune this on site.

To do this we opted to have the nozzle connection at an angle so we could direct the spray into the boiler and adjust by rotating the lance in the port.

The boiler consultant provided the PLC to control the urea skid and we provided a P&ID, electrical list, and a functional design specification to allow the programming of the system.

When we installed the system, we used a NOx analyser to obtain the NOx levels prior to setting up the required dosing rates. 

The figures shown were slightly higher than anticipated of 670mg/m3 but the O2 was also higher than normal operating which was based on 6%.

The CleanNOx skid was then commissioned and the pump was running at 55% dosing 3.78l/hr, the NOx levels were still slightly high of 560mg/m3

We then changed the nozzle with a wider spray angle (120°) from the original nozzle which was 25°.

The pump was then set to 100% dosing 7.6l/hr which reduced the NOx emissions to 486mg/m3.

We then made some minor adjustments to the lance position and angle to optimise the NOx reduction. 

The dosing was then reduced to 65% dosing 4.2l/hr of Urea.

With the lance position we were able to get the NOx down to 416mg/m3 thus being well within the required limit of <500mg/m3.

A further emissions test was carried out and the system passed within the MCPD requirements.

Our client said...

“I approached Filter Designs regarding an SNCR system after they were recommended to me by a trusted subcontractor. 

From the outset Filter Designs were very engaged with the project and offered invaluable advice on how best to integrate their system with the biomass boiler. They committed to a tight programme and delivered without any issues at all. 

They went above and beyond during the commissioning process to ensure the success of the project. They were very professional and approachable throughout. 

I wouldn’t hesitate to work with Filter Designs again on future projects.”

Projects Operations Manager