The Utilization Of Low-grade Heat In Production Of Acid Of JNMC The Adsorption Of Cr(Ⅵ) On CNTs

The first part:The Utilization of Low-grade Heat in Production of Acid of JNMCRecovery and utilization of waste heat in the sulfuric acid industry, especially utilization of low-grade heat, have attracted much attention for their many profits, and as an important sign of technology of acid production level. Currently Jinchuan Company has five sets of sulfuric acid plants. Due to the limitations of technical conditions and knowledge, at that time they didn't set low-grade heat recovery system in the process of acid. First, the study on the recovery potential of low-grade heat of the 530,000 tons acid plant has made. Based on study of the acid process procedure and a comparative analysis of the actual process with the similar process at home and abroad, the low-grade heat recovery program and the goal of the project had been proposed, the process flow of conversion of sulfuric acid production process had been redesigned. At the same time, Heat pipe devices of the low-grade heat recovery system had been optimized and selected, the design calculations of heat pipe heat exchanger had been completed. At last, the technical and economic evaluations on the expected results of the low-grade heat recovery project are presented. The advantages of the utilization project of low-grade heat of the 530,000 tons acid plant are the produced 37496t per year of low pressure steam and 3.18×1011 kJ per year heat energy.The second part:The adsorption of Cr (Ⅵ) on CNTsThe Carbon nanotubes (CNTs) absorbing chromiumions Cr(Ⅵ) from aqueous solution was analyzed, absorbing mechanism was discussed in this paper. This paper compares the effectiveness on the Cr(Ⅵ) adsorption of the dose of the purified CNTS, shake time and the solution pH were examined. Results showed that the modified CNTs had much better removing efficiency for Cr(Ⅵ) than that the as received ones. Namely, when the dose of the purified CNTS was kept as 0.2g, the Cr(Ⅵ) in the waste water containing 50mg·L-1 Cr(Ⅵ) were adsorbed up to a rate of about 98.61%, and the adsorption of Cr(Ⅵ) reached equilibration around a duration of 100 min. Moreover, the capacity was also significantly affected by the pH value of the solution between 2 and 7, and little change was observed above pH value of 7. And the relationship between adsorbing capacity qe and equilibrium mass concentration pe was found to be in accordance with the isothermal adsorption equations of Freundlich.