Device and method for dry and energy-saving production of polyaluminum chloride water purifying agent

Abstract

The invention discloses a device and a method for dry and energy-saving production of polyaluminum chloride water purifying agent. A furnace in fluid bed is used for heat supply, high-temperature flue gas generated by the furnace in fluid bed at 750-800 DEG C and air at the room temperature are subjected to secondary serial heat exchange, an air heat exchanger is used for further heating preheated air preheated to 70-75 DEG C by an air preheater to be at a temperature higher than 230 DEG C, the high-temperature flue gas is cooled to 200-230 DEG C after heat exchange by the air heat exchanger, the air at the room temperature is preheated to 70-75 DEG C by the air preheater, and the exhaust temperature of the flue gas is lowered to 100-120 DEG C. Polyaluminum chloride liquid supposed to enter a drying tower is subjected to negative-pressure spray concentration by dry tail gas with 0.5%-1.0% of drying powder and at the temperature of 105-120 DEG C, the tail gas is cooled to 70-80 DEG C while the 0.5%-1.0% of drying powder contained in the tail gas is absorbed by the polyaluminum chloride liquid, and the tail gas is exhausted after gas-liquid separation in an acid mist absorbing tower is completed. Therefore, the yield of a spray drying tower can be increased by about 5%, and comprehensive standard coal consumption for production of solid polyaluminum chloride per ton can be reduced by 60-90kg.

Description

technical field [0001] The invention relates to a drying and energy-saving method for producing a polyaluminum chloride water purifying agent, and also relates to a device for realizing the drying and energy-saving method for producing a polyaluminum chloride water purifying agent. Background technique [0002] In the "Guidelines for Key Areas of High-tech Industrialization with Priority Development" jointly compiled by the National Development and Reform Commission and the Ministry of Science and Technology, it is clearly stated that water treatment chemicals should be identified as key products for national priority development. Polyaluminum chloride is the most widely used and used water purification chemical agent. At present, the total demand for water treatment chemicals for industrial water purification in cities in my country is about 1 million tons, but the annual output is only about 600,000 tons. The market gap is very large, and there is a huge potential market a...

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Problems solved by technology

[0003] At present, in my country's polyaluminum chloride industry, 75% of polyaluminum chloride products are produced by drum drying method, and 25% of polyaluminum chloride products are produced by spray drying method, but even if it is produced by spray drying method There is still room for energy saving, because at present, 90% of the enterprises that adopt the spray drying method in the country use chain furnaces as hot blast stoves. For many coal-deficient provinces in the south, the requirements are too high. The utilization rate of coal combustion is only about 85%, and the flue gas has not been used for secondary use. Around 105°C-120°C, the temperature of the dry tail gas has not been used for secondary use. The powder with 1%-3% in the tail gas is absorbed by cold water spraying, and it has not been effectively used after the absorption treatment.

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