NOx gases comprise highly reactive compounds, mainly nitrogen dioxide (NO2) and nitric oxide (NO). They are byproducts of various industrial processes, in this case, stemming from an arsenic acid reactor used in the production of wood treatment chemicals. These gases contribute to air pollution, leading to smog formation, acid rain and pose a significant threat to respiratory health.

In 2021, Koppers initiated a project to upgrade their Wiri production facility. Pressure Worx had previously provided a heat exchanger for their existing plant and collaborated with Koppers and their engineering consultants at AECOM to design a larger uprated heat exchanger for the project. The project also required a new updated NOx scrubbing system. Leveraging Pressure Worx’s extensive experience in biogas scrubbing worldwide, we were initially contracted to support and review the Koppers/AECOM process, providing mechanical design services for the system. This collaboration ultimately led to the award for the manufacture and supply of five large stainless steel scrubber vessels, in addition to the uprated heat exchanger, in late 2022.

In the emission reduction process, NOx gases generated from the arsenic reactor enter Pressure Worx’s 3-meter-long stainless-steel shell & tube heat exchanger cooling the gas before it enters the multistage scrubbing tower solution. This consists of five scrubbing towers, each with a 1.2-meter diameter and heights of approximately 11 meters, connected in series. Inside the scrubbers, a series of chemical reactions occur, neutralizing and removing the harmful NOx gases from the exhaust stream.x

Pressure Worx provided the scrubbing towers, complete with stainless steel internals (liquid and gas distributors, packing supports, and hold downs), ceramic random packings, quick-release inspection/service manways, and handholes. Additionally, Pressure Worx designed and supplied the level transmitter chambers and manufactured the in-ground foundation steelwork and stud bolting to ensure a seamless installation on-site.

Pressure Worx successfully delivered all the equipment to Koppers’ Wiri site on schedule in August 2023. They now proudly stand as part of Koppers’ newly upgraded Wiri process facility, another milestone in New Zealand’s environmental efforts.

NOx scrubbing system

The post Clearing the Air: Our NOx Scrubbing Solution for Koppers appeared first on Pressure Worx.

Biogas cleanup

The first part of the process involves the cleanup of the biogas produced from the water treatment facility to remove contaminants such as Hydrogen Sulphide (H₂S) and various Siloxanes.  Pressure Worx designed and supplied two sets of gas scrubbers, one set for the H₂S removal and the other for the siloxanes. 

Pressure Worx provided lead-lag siloxane scrubbers using specifically formulated carbon adsorption media in our 3.7m high GRP/polypropylene lined vessels.  Our H₂S scrubbers use a granular iron oxide scavenging material, also in a lead-lag configuration of 3.5m high vessels. The four white scrubber vessels can be seen in the above photo at the left most edge of the site.

The main benefits of the lead-lag configuration are twofold.  Maintenance teams can change the media on the lead scrubber while the lag scrubber remains on-line, meaning no down time.  Furthermore, operators can ensure that the lead scrubber media is fully spent (utilised) before change out, with the lag bed providing a safety net against break through.

Screw compressor packages

After the scrubbers and as part of the front end of the process, Pressure Worx supplied three gas compressor packages on various biogas and hydrogen rich duties.  We selected oil flooded screw compressors in self-contained units from Adicomp as the ideal solution for Hazer’s CDP.  Adicomp is a leading global supplier of biogas screw compressors and Pressure Worx is proud to represent them across Australasia.  The partnership enables us to specify packages for local conditions and standards but manufactured with Adicomp’s extensive experience at their comprehensive facilities in Italy.

The target commissioning date for the Hazer Commercial Demonstration Project is Q1 2022.  A green hydrogen future awaits!

Three compactly designed and enclosed screw compressor packages were supplied to site with control systems complete with variable speed drives to optimise control and energy efficiency.

The post Working on a Green Hydrogen future appeared first on Pressure Worx.

Options include power generation with gas engines or microturbines and both are widely used to generate electricity either to support local electricity needs or to feed into the local grid.  Microturbines offer minimal moving parts, low maintenance, low noise and vibration and where there’s a nearby application for the heat generated by the microturbine, this meaningfully supports microturbine project economics.  However both microturbines and gas engines require LFG to be cleaned up before use.  Gas engine manufacturers typically require the high H2S content in LFG to be removed or reduced and siloxanes in newer landfills damage gas engine components and lead to excessive maintenance costs.  Microturbines often require complete removal of siloxanes prior to combustion to avoid early failure of expensive turbine components.

Pressure Worx have developed a variety of gas conditioning and biogas clean up solutions. We find no two sites are the same and biogas constituents will vary depending on many factors including the type and mix of organic waste. We can help you with designing and supplying a gas conditioning or clean up solution to match your raw biogas and meet the specifications for your end use requirements.

Another option for LFG is to use it in gas fired boilers.  While this comes with some challenges, the gas cleanup requirement prior to combustion is reduced.  Landfill gas emerges with variable pressures, volumes and methane content during a day and over time and boilers on LFG need to include gas trains designed and sized to accommodate this variability.  Combustion controls can provide for in operation adjustments for fluctuations in the LFG composition.  A well-designed LFG fired gas boiler installation provides stable heat for many applications, especially when combined with a LNG fuel train.  In some critical applications, dual gas trains with LFG and LNG options can allow uninterrupted operation.  Pressure Worx can offer custom designed dual gas trains for your requirements.

Contact us at sales@pressureworx.co.nz if you want to talk about your waste to energy project to better utilise biogas on your landfill.

• LinkedIn

The post Waste to Energy – making the most of landfill gas appeared first on Pressure Worx.

2x 100% Dual Redundant Fuel Gas Conditioning skid incorporating  gas heating, pressure reduction and filtration. Installed at Fonterra’s Te Rapa Co-generation Facility in New Zealand, to provide pressure controlled moisture free gas to the Gas Turbines.

The post Pressure Reduction appeared first on Pressure Worx.