Valve castings industry energy access and energy-saving measures

Pump achieve a variety of conditions by passing on oil, gas, water and other working fluid, the fluid delivery system is an important control components, widely used in petrochemical, municipal engineering, metallurgy, mining, water conservancy and hydropower, transportation, construction hardware , aerospace and many other industries, the market demand at home and abroad. Casting industry is the foundation of the valve industry, has now entered a phase of rapid development.
Although the country is casting a big country, but not casting power, the country accounted for 43.2% of total valve castings of world production, the number of enterprises and production in the world, companies in developed countries the average annual production of only 1/7 to 1/4, unit energy consumption is 1.5 to 2 times the developed countries, a huge energy saving space.
1.valve casting industry, "second Five-Year Plan" energy requirements
China Precision Casting Association in Beijing by the Ministry of Industry proposed: By 2015 the number of foundry business from 30,000 down to about 20,000 in 2020 to reduce to around 10,000, while significantly reducing casting energy consumption, 30% of companies reached the level of developed industrialized countries, in the "Eleventh Five-Year", based on the emission reduction targets to achieve a 10% reduction in energy consumption, the implementation of "China's foundry industry access" to close the waste of resources companies, so that the valve casting industry healthy and orderly manner development.
Comparison of the "Eleventh Five-Year" valve casting industry, we can draw the data (see Table 1).
2 valve castings energy industry access standards
2.1 overall energy consumption of castings
2.1.1 The proposed calculation method
Dollars per unit casting, smelting comparable overall energy consumption = (* smelting energy target overall energy consumption accounted for) / (1 + rejection rate).
2.1.2 tons of castings limit the amount of coal
Accordance with the "Twelve Five" casting unit product energy consumption requirements, combined with the foundry business is about average rejection rate of 8.8%, partially melting the casting energy production accounts for about 50% of the total energy consumption of castings, we calculate comparable existing enterprise cast iron unit comprehensive energy consumption limits as follows:
Iron castings (including ductile iron and gray iron) comparable unit comprehensive energy consumption ≤ 248 kgce / t
2.2 cupola energy access
2.2.1 cupola trends
About 80% of our iron castings with cupola melting, melting tonnage of different proportion in Figure 1.
As can be seen from the above data, the number of 5t / h and below the majority of small and medium cupola, from the long-term coexistence of diverse forms of ownership of economic structure, large, medium and small-scale foundry pattern of long-term coexistence is inevitable , and because domestic demand for valve castings are inseparable from SMEs, it will eliminate the need for a longer-term transition period.
2.2.2 tons of molten iron cupola limits of standard coal
Different energy cupola melting capacity of different tonnage, the smaller the unit energy consumption. According to the overall energy consumption in the region dropped valve castings business regulation, the calculation of energy consumption decreased coefficient K, (existing companies use 0.886, 0.887 selection of new enterprises), combined with Zhejiang Province, local standards, energy consumption decreased by multiplying the value of K, obtained Initial energy consumption, compared to the "casting industry access" (revised) energy access standards, limit energy consumption per ton of hot metal finishing calculation proposed new standards as shown in Table 2.
2.3 tons of molten iron electric power limits
Advocate the use of variable frequency electric furnace, medium frequency induction melting furnace, Zhejiang Province, local standards with reference to existing businesses and new enterprises, limit consumption per ton of hot metal finishing calculated as shown in Table 3.
3 energy saving measures
To ensure the "five-second" valve castings industry successfully completed energy saving targets, saving work in two ways, on the one hand the implementation of energy access for new businesses, especially medium and small castings business; hand on the existing enterprises to adopt effective energy-saving measures, the elimination of backward production capacity. Which for more than 30,000 companies existing valve castings summary of the most important energy-saving, energy-saving measures are as follows:
3.1 Waste heat recovery and reuse
Use cupola heat, hot water in the form of physical heat recovery cupola for life, can reach 80% of the waste heat recovery, improved energy efficiency.
3.2 Applicable melting equipment
Enterprises are required to be equipped with the capacity to match the smelting, refining, modeling, core, sand handling, cleaning and other equipment; using sand casting technology companies to be equipped with sand reclamation, reuse of waste sand equipment; promote the use of hot air, water, Long continuous operation cupola furnace; elimination of outdated equipment energy consumption, reduce energy consumption.
3.3 reduce the rejection rate
According to calculations, the casting yield per 1% increase per ton of molten iron to about 8 ~ l0kg produce more high-quality cast iron, coke saving 6 ~ 8kg, casting to reduce weight per 1% can reduce energy consumption by about 1 to 2%. From business point of view reflects the causes of waste, mostly concentrated in the liquid metal flow, porosity, size, cleaning and other defects, filling capacity can be increased by improving external conditions, the use of near-net shape casting technology to improve the casting dimensional accuracy, reduce processing waste.
3.4 smelting process transformation
Cupola Foundry fuel can be used, installation of computer control, dedicated high pressure centrifugal blowers and other advanced equipment, the use of oxygen-enriched air, the warm air, dehumidifying air and other processes, to achieve energy saving smelting; promotion of a cupola furnace double United smelting process, using feeder, charge preheating devices supporting advanced process equipment for reducing feeding time, shorten the melting cycle, improve electric furnace productivity, reduce energy consumption, especially in the high power density of frequency furnace effect more pronounced.