Many operators of coal fired power stations are adopting biomass resources as the fuel to extend the life of their stations, meeting increasing stringent targets for C02 emissions. At present, biomass co-firing in modern coal power plants with efficiencies up to 45% is the most cost-effective biomass use in power generation. Co-firing offers the added advantage – besides carbon free combustion – that the respective coal power plants using the fuel require limited incremental investment, and the cost of electricity generated may be competitive, especially if local biomass feedstock is available at low cost.
Biomass resources include agricultural residues; animal manure; wood wastes from forestry and industry; residues from food and paper industries; municipal green wastes; sewage sludge; dedicated energy crops such as short-rotation (3-15 years) coppice (eucalyptus, poplar, willow), grasses, sugar crops (sugar cane, beet, sorghum), starch crops (corn, wheat) and oil crops.
The availability of such a wide resource combined with carbon free emissions means that, on the surface, biomass looks to be the ideal fuel. However, this is not the case, because, in common with coal, biomass is both corrosive and highly abrasive, creating the same cost issues of plant protection and maintenance for power station operators.
The major problem is that biomass is not generally 100% virgin material. More often, it is recycled and becomes contaminated with materials such as silica, glass particles and ferrous materials (etc), resulting in wear on pipework at the high speeds – in some applications up to 40m/s - at which it is conveyed pneumatically.
This problem is evidenced in particular with one biomass material: sewage sludge. On its passage through sewers, sewage becomes contaminated with flood debris, sand, grit, deposits from environmental structures, residue from the land mass, plus metallics, and plastics.
Sand and grit, in particular, are a major problem, due to their high silica content. They are highly abrasive, causing problems of wear and erosion with the equipment used to treat, process, and finally, convey the sludge.
In addition to the wear on conveying equipment caused by contamination in biomass, the nature of the biomass material itself often causes problems. First, many types of biomass are fibrous: a factor that results in high amounts of wear when they are conveyed at high speeds. Second, fibrous biomass has to be conveyed at a velocity fast enough for it to flow; but not so fast as to produce dust, which can then cause Health and Safety issues by creating a hazardous environment.
Wear protection specialist, Kingfisher Industrial, is at the forefront of providing solutions to the problems of handling biomass in power stations. The company has provided comprehensive wear protection and burner protection solutions to coal fired power stations for decades. It was one of the first to address the particular problems of biomass when the resource moved into the mainstream of power generation.
Kingfisher61 (en-GB) First released on 01/10/2012 Page 2 of 2
Kingfisher has adopted an application specific solution to the handling of biomass, using its K-ZAS ceramic lining solution in pneumatic conveying pipework, and the K-CAST monolithic ceramic lining system for countering the different amounts of wear that occur in triffucators, non return valves (NRV's) and within the burners, where abrasion is at its greatest.
The K-ZAS ceramic lining solution provided by Kingfisher is designed for the protection of plant and equipment encountering severe abrasion and erosion attack from bulk solids being conveyed, stored or processed by mechanical, pneumatic or hydraulic means. Rated nine on the MOHS hardness scale and having excellent thermal shock resistance, K-ZAS is ideally suited to counter excessive abrasion and high temperatures for applications within the power generation, bulk solids handling and mineral processing industries.
The K-CAST ceramic lining system offers the key advantage of constant performance at elevated temperatures – up to as high as 1200oC. It also provides a highly flexible solution to abrasion induced problems, offering excellent resistance to both impact and sliding induced abrasion.
About Kingfisher Industrial
Kingfisher Industrial provides wear solutions for process plant used to convey, process or store bulk solid materials, in either dry or hydraulic states. Such plant often suffers premature wear due to handling large quantities of materials at velocity in a constant operational cycle. With its range of ceramic, metallic and polymer protection systems, Kingfisher can overcome wear problems; engineering suitable protection systems that can add many years’ of life to a plant, and in some cases outlast the design life of a process completely. These solutions cater for the operating criteria, budget and life cycle of either new equipment - particularly when initially installed - or existing equipment, which can be retrofitted with a protection system to add to its current asset value.
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