Climate change, for much of the past two decades if not more, has been a driving factor behind the push to increase electrical power production by renewable, non-fossil fuel means. This has seen a meteoric rise in the number of wind turbine and solar farm developments all across the UK and many other parts of the world.
However, whilst the reduction in CO2 emissions has been behind this aspect of the industry, a further driver behind the minimising of production of greenhouse gasses has been the push to reduce methane (CH4) production from landfill sites by the use of recycling. Methane is believed to be equally, if not more, influential in terms of climate change as CO2, so any reduction in the output to the atmosphere of CH4 is seen as a major step forward in the climate change fight.
The separation of food waste from general waste has helped this cause considerably, but in the UK this still leaves a significant amount of non-recyclable waste being sent to landfill. Latterly, the volume of waste has been increasing the pressure on landfill sites, so many companies and individuals have been trying to find ways to simultaneously answer both climate change and landfill questions.
WASTE RECYCLING FOR POWER
This drive has led to the development of power plants to provide electricity through the use of non-recyclable waste as fuel or through the burning of biomass products such as waste wood. Of course, the establishment of plants to undertake the generation of power from these fuel sources is no less complicated than the way in which fossil fuel burning plants are designed.
One aspect of the power production that has always needed an answer is how to handle the wastewater outputs from such plants. On the cooling side of the plant, a major challenge is how to handle the initial high-temperature effluents in a manner that will not only leave the local environment unaffected but also leave undamaged the drainage system installed on any particular plant.
Whilst standard drainage systems will handle reasonably high temperatures, they will not in general be able to withstand the high output temperatures from power production plants. Furthermore, as the high temperature flows are often intermittent, any drainage system installed will have to be able to handle not just high temperatures but also significant thermal shock as flows vary throughout the power generation operation. To answer this demand, a special type of pipe was needed and today this is one of the specialist pipe ranges offered by Naylor Drainage of Barnsley, UK.
Having manufactured clayware pipes for over 125 years, the design and manufacturing prowess of Naylor Drainage is without question. Having listened to the needs of industry in terms of the requirement for pipes that can handle high temperature environments, the company undertook development of its existing pipe systems with a view to providing a pipe to meet this need.
Today the company offers a range of pipes known as Thermachem, designed to handle both high temperature and chemically aggressive environments across of range of sizes from DN100 to DN500 and all popular pipes sizes in between. There is also a range of bends and fittings to suit most drainage circumstances.
Thermachem is believed to be the world’s leading thermal shock and chemical resistant ceramic pipe system, and is manufactured from Naylor’s unique Hathernware material. Two of the biggest threats to ceramic pipes and other pipe materials in the process and power production industries are chemical attack and temperature change. When the pipeline is regularly subjected to a rapid change in temperature, the ceramic body can be vulnerable to thermal shock. Thermachem is the only ceramic material suitable for use in the areas which are subjected to intermittent discharges of hot and cold effluents such as hospital sterilisation units, boiler blow down drainage, laboratories, food processing, beverage production and more recently power plant drainage systems with temperature changes of up to 120oC.
Legal obligations imposed upon companies by the Environmental Protection Act 1990 have also resulted in increasing awareness of the potential discharge impact of industrial effluents into ground water or rivers. This has led to an increasing trend for ‘worst-case’ scenarios to be designed into new structures. This is especially applicable to drainage installed below the main floor slab, where repair or process amendment would prove prohibitively expensive. Thermachem pipes and fittings are designed to handle most chemicals and aggressive discharges.
The Thermachem drainage system is approved to EN295-1 Standard by BSI as well as overseas certification bodies such as Benor. Thermachem pipes have the standard G type plain ended coupling system which allows it to be seamlessly connected to Naylor’s Densleeve range of standard vitrified clay pipes and fittings, where downstream dilution or heat dissipation allows a switch into standard rather than specialist piping.
Some of the more recent examples of how Thermachem has proven its usefulness in the recyclable/renewable generation of power are the Templeborough Biomass power plant, the Beddington waste recycling plant and the Battlefield EfW (Energy from Waste) Plant.
The Templeborough Biomass Power Plant is currently under construction with the use of Naylor Thermachem pipes. In common with other biomass materials, wood based biomass materials all capture energy and CO2 through the process of photosynthesis as they grow, and when burned as a fuel, release only the same amount of CO2 they captured back into the atmosphere. Biomass is therefore classed as a renewable energy source and this plant will help towards the UK government’s ongoing renewable energy targets. Once fully operational in 2017, the plant will generate 41 MW of green electricity, enough to power 78,000 homes and save over 150,000 tons of CO2 every year. Naylor Thermachem pipes of DN100, DN150, DN225 and DN300 have been installed and connected across the site using chemical push fit couplings with EPDM seals to handle the high temperature discharges around the site, particularly from directly under the boiler where steam is regularly released to prevent it condensing.
At the state of the art Beddington Energy Recovery Facility (ERF), Naylor Thermachem has also been installed as the drainage system. The facility has been designed to handle around 275,000 tonnes of non-hazardous waste per year, which will generate around 22 MW of electricity to supply to the National Grid. The site is based at an existing landfill and recycling centre, making excellent use of existing access. It will help divert up to 95% of non-recyclable waste from the local area from going to landfill, saving not only space at the landfill site and providing significant renewable energy output but also making significant cost savings for the local taxpayer. On this site, Thermachem pipes of DN225 and DN300 were used in conjunction with EPDM Push fit couplings.
The Battlefield EFW plant in Shrewsbury will treat approximately 90,000 tonnes of Shropshire’s waste per year, generating enough electricity to power around 45,000 homes. With recycling schemes already in place, landfill for the region will be reduced to just 5%. Thermachem pipes were chosen for this project due to their excellent resistance to thermal shock. They will carry boiler blow down water from the boiler to a holding tank, where water will be cooled and treated for re-use or discharge. Different coloured couplings, usually used to distinguish the coupler seal material, were used to identify the two different pipelines carrying different discharges. Despite the relatively short (150 metre) run of the pipeline, pipes of two different diameters - DN150 and DN225 - were utilised.
So, with increasing numbers of similar facilities having already been built or in the process of construction or planning, it appears highly likely that Thermachem pipes of all diameters will continue to underpin renewable energy production both in the UK and indeed worldwide (Naylor is an active exporter).
Commenting on the growing use of Thermachem pipes for these types of installations, Edward Naylor, CEO of Naylor Drainage said: “The increasing demands of industrial projects like these was exactly the sort of use that we expected as we developed our Thermachem product range. Our expertise in this field allows us to help engineers and designers by providing solutions and technical input into the most technically challenging situations. Power plants such as these have enormous benefits in terms of climate change and Thermachem’s use allows us to play our own part in the world-wide drive towards a cleaner and greener economy.”