Dilute sulfuric acid resource utilization system

Abstract

This invention provides a dilute sulfuric acid resource recovery system that utilizes the principle of multi-effect evaporation to regenerate and recover dilute sulfuric acid waste liquid. The system includes a first-effect heating section, a second-effect heating section, and a heat exchanger. The first-effect heating section receives dilute sulfuric acid and a steam source, causing the dilute sulfuric acid to evaporate and form first-effect concentrated sulfuric acid and first-effect steam. The second-effect heating section further concentrates the first-effect steam using it as a heat source, generating second-effect concentrated sulfuric acid and second-effect steam. The heat exchanger condenses the second-effect steam to form condensate and recover its latent heat. By utilizing steam heat energy in stages, energy efficiency can be effectively improved, operating costs and acidic waste liquid discharge can be reduced, achieving the goals of sulfuric acid resource recycling and energy conservation and emission reduction in industrial processes.

Claims

1. A dilute sulfuric acid resource recovery system, comprising: A first-effect heating section receives a dilute sulfuric acid and a steam source, and heats the dilute sulfuric acid to output a first-concentrated sulfuric acid and a first-effect steam; a second-effect heating section receives the first-concentrated sulfuric acid and uses the first-effect steam as a heat source to heat the first-concentrated sulfuric acid to output a second-concentrated sulfuric acid and a second-effect steam; a heat exchanger receives the second-effect steam for condensation and outputs a condensate; wherein the heat energy provided by the steam source is utilized stepwise through the first-effect heating section and the second-effect heating section to recover the sulfuric acid component in the dilute sulfuric acid and form the second-concentrated sulfuric acid.

2. The dilute sulfuric acid resource recovery system as described in claim 1, wherein, The steam source is waste heat steam from boilers, cogeneration systems, or recovered steam from chemical processes.

3. The dilute sulfuric acid resource recovery system as described in claim 1, wherein, The concentration of the dilute sulfuric acid is 40 wt% to 70 wt%.

4. The dilute sulfuric acid resource recovery system as described in claim 1, wherein, The concentration of the first concentrated sulfuric acid output from the first effective heating section is 50 wt% to 75 wt%.

5. The dilute sulfuric acid resource recovery system as described in claim 1, wherein, The concentration of the second concentrated sulfuric acid output from the second heating section is 70 wt% to 99 wt%.

6. The dilute sulfuric acid resource recovery system as described in claim 1, wherein, The temperature of the steam source is between 130°C and 160°C, and its pressure is between 2.7 bar and 6.0 bar.

7. The dilute sulfuric acid resource recovery system as described in claim 1, wherein, The temperature of the first-effect steam is 110°C to 120°C, and its pressure is 1.4 bar to 2.0 bar.

8. The dilute sulfuric acid resource recovery system as described in claim 1, wherein, The temperature of the double-effect steam is 95°C to 105°C, and its pressure is 0.85 bar to 1.2 bar.

9. The dilute sulfuric acid resource recovery system as described in claim 1, wherein, The steam source is water vapor.

10. The dilute sulfuric acid resource recovery system as described in claim 1, wherein, The heat exchanger is further used to recover the latent heat of condensation of the second-effect steam in order to preheat the dilute sulfuric acid entering the first-effect heating section.

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