The Assessment And Analysis Of The Waste Heat Resource And Energy Saving Potential In Ferroalloy Production Process

Ferroalloy production process is an intensive energy consumption, large amounts of energy are lost in the form of exhaust flue gas, slag and production with high temperature.With the growing of energy crisis, energy saving becomes a survival issue for ferroalloy production enterprises. The assessment and analysis of its energy saving potential are great significance and prospect.To study the number of waste heat in ferroalloy production process and assess its energy saving potentaial, testing continuly the flue gas of submerged arc furnace, arc furnace, lime kiln and manganese ore rotary kiln for21days. The temperature distribution, average flow rate and chemical composition were recived. From the gas composition of ferrosilicon submerged arc furnace, the recyclable waste heat resource of the semi-closed furnace is their thermal waste heat. Based on the first and second thermodynamics, the recovery heat energy and exergy are taken as the indicators for quantity and quality. Based on the full utilization and level balance concept, level coefficient is taken as the full use of quality indicators in the assessment of waste heat resources. The approache is reasonable、intuitive and comprehensive. The calculation of high temperature flue gas is given. The quantity and quality of waste heat resources are23.42MW and5.82MW. From level balance concept, level coefficient of each furnace flue gas is calculated and the most potential energy saving are flue gas of ferrosilicon/2#submerged arc furnace, lime kiln and manganese rotary kiln. The quantity and quality of them are17.88MW and5.52MW.To get annual waste heat of flue gas, establishing material and energy balance model of ferrosilicon/2#submerged arc furnace, the material flow were analyzed. Combined with the test result, energy balance was calculated based on the material balance. The annual waste heat of flue gas was verified and the high temperature of slag has great potential.To completely assess the waste heat rescource, testing number and temperature of the slag. Through energy method, the recoverable energy of high temperature slag is calculated for2.27×105GJ. Based on the exergy analysis principles and level coefficient concept, the entropy, exergy value、enthalpy and energy level coefficient in various temperature of slag are given. According to the test temperature, the energy value is1.52×105GJ and level coefficient is0.701. CoMPared with the available ways of waste heat recovery of slag, the dry granulation method has outstanding advantage with water saving and high recovery efficiency.The recoverable energy and exergy are3.52MWand1.61MW.Due to low coefficient of ferroalloy production waste heat, power generation alone is unreasonable. According hot steam demand and only recovering flue gas situation, the termal energy utilization factor and power generation coefficient are given coMPare the power generation with the combined heat and power (CHP). The result is that:the CHP has higher energy utilization and energy-saving potential. At the same time, proposed integrated recovery flue gas and slag by power generation and cogeneration, the comprehensive recovery by CHP is the best way for energy saving.