Taming tough bamboo for industry
Materials tests show that bamboo has ideal properties for some specialized high-temperature cooling processes.
Materials scientists’ evaluations identify bamboo as an ideal product for some heavy industrial uses such as cooling of extreme high temperature water and steam. But perhaps its most attractive aspect is the sustainable value chain it offers over materials such as PVC – sourced from sustainable forests, more resistant for temperature applications, and recycled back into nature at the end of its product lifetime.
Lu Jiping, General Manager, of Yixing Hengda Bamboo Grid, China: “Stress and durability tests for bamboo screens used to cool 900C steam to water, show a product lifetime of 15 years – three times that of PVC – and fully biodegradable at the end of product lifetime ? “
Bamboo is generally known for its uses as garden furniture, for low-cost construction in some developing countries. And more recently, for more refined uses such as high-quality flooring and a range of high-design products for furniture, special objects and innovative architecture design applications.
Over the past decade, evidence is emerging to show that this material has properties ideal for high-value industrial and engineering applications. Some of these new uses are catching on in the industrial engineering communities but not yet widely known. One example is Yixing Hengda Bamboo Grid, the engineering services company, based in CITY, in central China, that has made its place as the country’s market leader for bamboo grids used in high-temperature cooling processes in heavy industry.
Lu Jiping, the company’s General Manager, did not start his working life as a bamboo professional. He grew into it as a construction engineer, tasked with solving a problem for a client in the industrial power sector. A steel company came to him with a question: steel and concrete were not withstanding the high-temperature steam in cooling towers in their power generation process. Steam emerges from the process at temperatures of 900C and is cooled to 30C through a series of grids in the plant’s cooling towers before being recycled back into the production process. A new material was needed. But which one?
Materials scientists evaluate bamboo properties
Ten years ago, the HD technical team started stress and temperature evaluations with Chinese materials science institutes in Shanghai, evaluating a range of materials. They looked at concrete, engineered plastics and various steel composites to be used as in the webs of cooling screens in the towers.
40 years ago, engineering contractors made cooling screens for heavy industry from wood, evolving to concrete and metal, to better withstand high temperature steam for industrial cooling in factories and power plants. This progressed to engineered plastics, where today, PVC is commonly used in cooling towers worldwide, Jiping explains: “In our research with the material scientists we tested many types and combinations of materials, looking for better heat stress performance and longevity. Then we came across bamboo. It was not a natural choice as the material has no history in engineering and heavy industry, he says.» Engineers’ thinking naturally leans toward high-tech and new composite materials.
Based on initial results of the bamboo tests, the research team evaluated further, finding that its performance in extreme high temperature situations surpassed that of plastics.
Under the extreme high temperatures in cooling towers of power plants and manufacturing facilities, plastic grids need replacing every five years. Bamboo’s properties show a 15 year lifecycle. It also performs well in temperature extremes. Materials used in cooling processes in factories in Northeast China, for example, are exposed to winter temperature rages of -40 to 900C.
Superior resistance and sustainability
But probably the biggest benefits of bamboo for widespread use in industrial cooling and related applications are its superior environmental sustainability aspects. The bamboo value chain for high-temperature cooling grids – from raw material, to transformation, to product performance, lifetime and environmental recycling – is impressive.
HD sources its bamboo supply by managing natural national bamboo forests under an agreement with local farmers, who maintain them – creating long-term local employment.
Unlike a traditional forestry supply operation, the bamboo is regularly trimmed, not fully harvested as trees are. The bamboo plants remain in the forest and continue growing – sequestering carbon, while providing a continuous supply of material for the cooling grid industry.
After 15 years of productive use in power plant and industrial cooling, HD’s cooling grids end their product lifecycle as organic waste or fertilizer, returning back to the ecosystem. Competing PVC materials cannot be organically decomposed in this way. HD is the current market leader, and one of 40 Chinese producers of grids and similar bamboo products for heavy industry.
Jiping explains that the global market potential for this product alone is vast. Looking only at China, a 300MW facility requires 4800 cubic meters of bamboo grid for cooling. Extending this scenario to the global power sector cooling market shows a huge market and significant green benefits to all countries for plastic replacement for cooling screens with a more robust and green solution.
He is confident that this innovative use of bamboo will attract more interest of industries globally as the green benefits of these bamboo industrial products become better known. Cooling grids can serve power, textile, chemical, pulp and printing and dyeing production. There are many other uses for this resistant and flexible material in engineering and industry applications.
And what other similar innovations are on the horizon that tap the bamboo’s properties? The engineers are at work….watch this space.