Method for cooperatively treating high-salinity wastewater by using low-calorific-value combustible gas

Abstract

The invention discloses a method for synergistically treating high-salinity wastewater by using low-calorific-value combustible gas, which supplements various heat energy required by each stage of high-salinity wastewater treatment by using heat energy generated by combustion of the low-calorific-value combustible gas, and realizes synergistically treating the high-salinity wastewater while treating the low-calorific-value combustible gas. According to the invention, heat energy generated by combustion of the low-heat-value combustible gas can be effectively utilized; latent heat of steam generated by the process can be fully utilized; the method has the advantages of low scaling rate, low energy consumption, low operation cost and the like; the low-calorific-value combustible gas can be converted into electricity and high-temperature flue gas; effective treatment and resource reutilization of the low-calorific-value combustible gas are realized; according to the method, the problem ofutilization of the low-calorific-value combustible gas is solved, pollutants or salt in the high-salinity wastewater can be effectively separated from water, effective treatment and resource reutilization of the high-salinity wastewater are achieved, and the method has good application value and application prospects and has very important significance in resource reutilization of the high-salinity wastewater.

Description

technical field [0001] The invention belongs to the field of high-salt wastewater treatment, and relates to a method for co-processing high-salt wastewater by using combustible gas with low calorific value. Background technique [0002] High-salt wastewater refers to wastewater containing high concentrations of salt and pollutants, usually with a total dissolved solids (TDS) content of ≥8000mg / L, such as power plant desulfurization wastewater, reverse osmosis concentrated water (such as landfill reverse osmosis concentrate), etc. Wastewater usually contains a large amount of salt and high concentration of organic matter, and its biodegradability is extremely poor. Therefore, the treatment of this kind of wastewater has always been a hot and difficult research topic in this field. Low calorific value combustible gas Combustible gas with methane concentration of 30% to 70% or other combustible gas with equivalent calorific value, such as landfill gas (also called landfill asso...

AI Technical Summary

Problems solved by technology

Low calorific value combustible gas Combustible gas with methane concentration of 30% to 70% or other combustible gas with equivalent calorific value, such as landfill gas (also called landfill associated gas or landfill gas), anaerobic system The produced biogas, chemical process associated combustible gas, etc., are difficult to be effectively used due to the low calorific value of these gases. At the same time, direct discharge of these other gases may cause adverse effects on the environment, such as increasing greenhouse gas emissions. quantity

[0003] The patent document with the application number 201610512496.X discloses a submerged combustion evaporation concentration method, which adopts the "stripping + evaporation + concentration" three-stage submerged combustion evaporation concentration process to evaporate and concentrate high-salt organic wastewater, although in this method Low-quality gas is used as the energy source, but the high-temperature flue gas is directly passed into the wastewater for heating, which has the following problems: it is easy to cause excessive evaporation intensity and easy to generate scaling; the concentration factor in actual use is low; A large amount of pollutants and heat are entrained in the produced steam, and the latent heat of evaporation carried by the evaporating steam cannot be effectively recovered or utilized, and these entrained pollutants need to be removed through secondary combustion treatment, resulting in more complicated overall process and higher energy consumption

In addition, in the existing high-salt wastewater treatment process, the secondary steam mechanical compression evaporator (MVR) is simply used for crystallization and concentration. Although the energy utilization rate is improved, a large amount of electric energy will still be used, resulting in a large power consumption

It can be seen that the existing high-salt wastewater treatment process (or treatment equipment) has the following defects: (1) the combustible gas with low calorific value cannot be fully utilized, and the heat energy generated by combustion cannot be effectively recovered or utilized; (2) the heat exchanger is easy to Fouling, resulting in poor heat transfer efficiency and high operating costs; (3) Cannot make full use of the latent heat of steam produced by the process; (4) High power consumption