by clicking the arrows at the side of the page, or by using the toolbar.
by clicking anywhere on the page.
by dragging the page around when zoomed in.
by clicking anywhere on the page when zoomed in.
web sites or send emails by clicking on hyperlinks.
Email this page to a friend
Search this issue
Index - jump to page or section
Archive - view past issues
button in toolbar for more information.
Metal Casting Technologies : December 2007
Environmental Report METAL Casting Technologies December 2007 28 RAISING ENERGY EFFICIENCY AND REDUCING GREENHOUSE GAS EMISSIONS The United Nations Development Programme has been conducting a project in China, since 1995, designed to raise the energy efficiency and reduce greenhouse gas emissions of the rural industrial sector. It selected several TVEs to carry out demonstration projects involving improved technologies, innovation, maintenance techniques, technical transformation, staff training and commercialising the improved technologies. To date, nine pilot demonstration sites have been developed leading to the selection of 118 TVEs for replication; the pilot programs have resulted in GHG savings of 300,000 tons/yr of CO2; 118 TVEs replicated will result in GHG savings of more than 1.1 million tons annually of CO2; and 1,200 people have been trained through workshops on new technology and energy efficiency. Brick-making, coking, metal casting and cement were selected to be the four sectors to be covered by the project, which together accounted for 57.2 per cent of total TVE's emissions of 117.8 million tons of CO2 in 1995. Their average energy consumption is 30 to 60 per cent higher than the state-owned-enterprise sector using currently available technologies. TVEs are also major contributors to local air and water pollution and health hazards for employees. Of total energy consumed, 20 per cent is in the form of electricity (largely coal-based), 10 per cent as fuel oil and 70 per cent in direct coal combustion. At the beginning of the United Nations program, in-depth surveys were made of 76 TVEs to improve understanding of their current technology inventory, product qualities, financial circumstances, market conditions, investment plans and barriers to technology improvement. What they found was that the TVE metal casting industry is highly decentralised and uses a diverse set of often locally manufactured and not well-integrated technologies. The character of production is very customer specific. The industry is not homogenous in terms of its technological capabilities: some metal casting TVEs supply to SOE customers in the domestic market as well as international customers. LOW TECH, HIGH REJECTION RATES AND NO POLLUTION CONTROL Low-tech production technologies and the lack of quality control mechanisms in the TVE metal casting industry lead to high energy consumption and high reject rates. This leads to local and global pollution: ■ Lack of quality controls (skill, process, equipment related) in various stages of production lead to very high rejection rates (more than 20 per cent, compared to two per cent in developed countries), ■ The use of inefficient melting, non-integrated production processes and the use of foundry coke of ill-defined properties and uncontrolled quality lead to high energy consumption. ■ Low profitability, small size and lack of enforcement of environmental regulations do not facilitate investments in pollution control equipment. However, improved production techniques and processes could lead to on-site energy saving in the four TVE sectors subject to the pilot program, of between 20 and 60 percent. In addition, the implementation of improved production processes has important implications on the properties of outputs/ products and downstream energy consumption. A typical, average investment could lead to a reduction of 2,000 tons of CO2 per year. Considering the very large number of possible investments, GHG emission reduction potential for the four sectors is above 50 million tons of CO2 per year. The production of metal castings relies on an integrated, multi-step production process. Industry experts identified the following elements that should be implemented in an integrated fashion: ■ upgrade sand processing systems to mechanised and/or semi- automatic systems; ■ upgrade furnace to cupola and electrical furnace duplex systems, or hot cupola systems; and ■ mechanisation and automation of the molding systems. Foundries also need to improve house-keeping as well as quality control in their operations. According to experts working with the UN project, most of the backward technologies should not be upgraded but their operations should terminate and their order-books be transferred to modern producers. By July this year, all elements of the UN project had been completed, except for the publication of a book entitled "A Practice of Energy Conservation and GHG Emissions Reduction in Chinese TVEs" that will be produced by the end of 2007. The Nanjing Moling Foundry, one of the pilot project sites involved in the United Nations Development Programme project focused on energy conservation and GHG emission reduction in Chinese Township and Village Enterprises. Images courtesy of the United Nations Development Programme, China