Efficient and energy-saving salt and sodium sulfate co-production process

Abstract

The invention discloses a high-efficiency energy-saving salt-sodium sulfate co-production process, which is characterized in that refined brine in the process is preheated in a salt production system and then is subjected to evaporative crystallization, salt is discharged in different effects by an evaporation tank, mother liquor is discharged in a downstream manner, and the mother liquor enters a sodium sulfate production system; the mother liquor is preheated in the nitrate preparation system and then enters a nitrate evaporation tank to be evaporated and crystallized, and the mother liquor subjected to nitrate separation by the nitrate evaporation tank enters the salt preparation system to be circulated; wherein a heat source of a first-effect evaporation tank in the salt manufacturing system is live steam, and a heat source of a next-effect evaporation tank is part of secondary steam of a previous-effect evaporation tank; heat sources of a nitrate evaporation tank and a preheater in the nitrate preparation system are part of secondary steam of an evaporation tank in the salt preparation system; and secondary steam evaporated by a nitrate evaporation tank in the nitrate preparation system returns to the salt preparation system, and is used as a heat source for evaporation and preheating together with secondary steam of the salt preparation system. According to the process, the secondary steam of the salt manufacturing system serves as a heat source of the nitrate evaporating tank and the preheater in the nitrate manufacturing system, a steam jet pump is omitted, the heat efficiency is high, steam consumption is low, and the energy-saving effect is remarkable.

Description

Technical field [0001] The present invention relates to the field of salt and nitrate cogeneration technology, particularly to a highly efficient and energy-saving salt nitrate cogeneration process. Background [0002] At temperatures above room temperature, NaCl-Na 2 SO 4 -H 2 The solubility of NaCl in O brine system increases with the increase of temperature, Na 2 SO 4 The solubility decreases with the increase of temperature, based on this property, domestic mineral salts basically use the evaporation method of salt and nitrate co-production process method to make salt and nitrogen. [0003] The existing salt and nitrate co-production process is mostly to mix the raw steam through the steam jet pump to suck part of the secondary steam into the nitrate evaporation tank as a heat source, and the nitrate mother liquid enters the salt making system after two flashes and cooling. The steam jet pump used in the process is mostly imported equipment, its price is high, the supply cycl...

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Problems solved by technology

Most of the steam jet pumps used in this process are imported equipment, which are expensive and have a long supply cycle. However, domestic steam jet pumps are used in unstable operation, large fluctuations in operating parameters, and are prone to failure. They need to be shut down for maintenance, which increases the operating cost. cost, and the cost of energy consumption is high, which does not meet the requirements of energy saving and emission reduction; the mother liquor for nitric acid production enters the salt production system after two flash evaporations and cooling, the number of equipment is large, the floor area is large, and the equipment is easy to scale and block pipes, and the continuous operation cycle Short, frequent false washing is required, increasing energy consumption

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