分解分级中间降温技术改造

Intermediate Cooling Technological Reform of Decomposition and Classification

以氧化铝生产规模为1 600 kt/a,分解分级工段为两条生产线,分解分级单条线氧化铝产能为800 kt/a的拜耳法氧化铝厂为例,通过对新型分解分级中间降温工艺技术进行热平衡计算及设备选型计算,分别就建设投资和运营成本两方面将新型分解分级中间降温工艺与传统中间降温工艺进行对比。阐述了一种新型拜耳法氧化铝厂分解分级工段中间降温工艺技术,采用在中间降温段的每台分解槽内设置加热管束式分解槽换热器,代替传统分解槽外置换热器的方式,取消了中间降温料浆泵。加热管束式分解槽换热器内的循环冷却水通过间接换热方式与分解槽内氢氧化铝浆液进行热交换,将分解槽内氢氧化铝浆液温度降低到生产所需温度。

Exampling by an alumina plant of Bayer process with production scale of 1600 kt / a,two production lines in decomposition and classification and alumina capacity of 800 kt / a for a single production line,thermal equilibrium and equipment selection of a new intermediate cooling technology in decomposition and classification were calculated. And the new technology was compared with the traditional one in the construction investment and operating costs. A new intermediate cooling technology for the decomposition and classification in alumina plants using Bayer process was introduced in this paper. Heat exchangers with heating pipe bundle were arranged in each decomposer in intermediate cooling stage to replace the traditional methods and thus slurry pumps for intermediate cooling were removed. The heat exchange between the circulating cooling water in the heat exchanger and aluminium hydroxide slurry in the decomposer was realized through indirect heat exchange. And then the temperature of aluminium hydroxide slurry in the decomposer was reduced to meet the production requirement.