Project BI – CleaNOx Selective Non-Catalytic Reduction (SNCR) System

• Clinical Waste Incineration
• SNCR Skid
• Compressed Air and Urea Solution Control Panel
• 2 Bespoke Urea Injection Lances

We were originally contacted via a third party who were putting together a FEED study for an upgrade for a clinical waste incineration based at the Derriford hospital in Plymouth. The main order then subsequently came from Brothwell & Irvine who were the principal contractor who were overseeing the upgrades to the facility.

The specification we were given was:

Using our in-house reagent waste calculator where we can define the sorbent usage based on the raw gas emissions which was NOx in this case.

This spreadsheet can also give the client an approximate OPEX based on the current market prices.

The raw value we were given was to reduce the NOx from 400mg/m³ to 180mg/m³ as defined by the specification given (above) and to allow the site to comply with the BREF requirement for NOx emissions of >180mg/Nm³.

Once we knew how much urea is needed, we can then size the equipment needed to ensure these emissions are met.

The scope of the project is as follows:

• CleanNOx FIBC urea skid compromising:
• Duty / Standby Dosing pumps
• 3-way Diverter Valve
• Duplex Strainer
• Non return valves
• Urea pressure transmitter
• Air pressure transmitter
• Air regulators for Atomising / Barrier Air
• Mains Isolator
• MCB’s c/w Auxiliary trip contacts
• Control Relay’s
• Control Terminals
• Trip Indicator lamps on front of panel

• 2 Bespoke Urea Lances (one spare)
• 2 Urea spray nozzles
• 60m of EPDM hose including fittings

CleaNox control panel comprising:

• Rockwell Micrologix 1400 PLC System
• Our hardware offer is based on a Rockwell architecture
• Supply of all electrical hardware
• Rockwell Low Voltage Control Gear
• Network Switch

Our client provided us with a 3d model and CFD information so we could retrofit the lance into the ducting which would have the correct temperature requirements for the urea dosing and allow us to size the correct spray nozzle.

We then made the long trip down south to take measurements to facilitate the installation and determine where the SNCR skid and control panel would be sited.

Once the FAT on both the SNCR skid and control panel were completed these were sent direct to site and our client had their electrical installation team wire the skid to the control panel.

After a short delay we were then invited back to site to carry out the commissioning of the system.

Due to an issue with the site’s thermocouple reading incorrectly we had to force the temperature in the control panel so that the system would run, we had an interlock in the controls where the system couldn’t dose urea unless it was within the temperature range of 850°c - 1050°c.

Once the thermocouple was replaced, we were then able to log in remotely using the control panel IXON (remote access) to make the changes to the software without the need to visit site. This also allows us to check on the system and diagnose issues if they arise.

Stainless steel SNCR skid and control panel.

Bespoke ceramic coated urea lance with quick release fittings to allow quick removal from the ducting.

Bunded UREA IBC with quick release fittings and fitted with a float switch to identify when the urea IBC needed changing

Sites CEMS (continuous emissions monitoring system) to show us the NOx and Ammonia levels.

The system has been operating well since the install / commissioning and has reduced the NOx level set out in the specification given to us.