Method for preparing sulfuric acid by pyrolyzing alkylated waste sulfuric acid at high temperature

Abstract

The invention relates to a method for preparing sulfuric acid from waste sulfuric acid, in particular to a method for preparing sulfuric acid by pyrolyzing alkylated waste sulfuric acid at high temperature. The method comprises the following steps: (1) pumping waste sulfuric acid into a high-temperature pyrolysis furnace to form mist waste sulfuric acid drops; (2) introducing natural gas and air into the furnace and controlling the temperature in the furnace to be 1,000-1,100 DEG C; (3) cooling SO2 and H2O to be at 330-400 DEG C; (4) humidifying by spraying dilute acid; (5) performing a catalytic oxidation reaction, so that SO2 is converted into SO3; (6) cooling SO3 gas to be at 260-320 DEG C, so as to form saturated steam; and (7) performing heat exchange between SO3 gas and air for further cooling, wherein the final temperature of cooling is 60-120 DEG C; and spraying 98% sulfuric acid with the temperature of 70 DEG C to absorb the generated SO3, so as to form the sulfuric acid. The invention provides a brand-new regeneration method of waste sulfuric acid, so that the technological processes are greatly simplified, equipment layout is reasonable, the operation is simple and convenient, the economic benefits are obvious, and the comprehensive energy utilization is high.

Description

technical field [0001] The invention relates to a method for producing sulfuric acid from waste sulfuric acid, in particular to a method for producing sulfuric acid by pyrolysis of alkylated waste sulfuric acid. Background technique [0002] Concentrated sulfuric acid is widely used as a catalyst in petrochemical and organic synthesis industries, and this process will produce a large amount of waste sulfuric acid. For example: In the oil refining industry, isoparaffins and olefins are alkylated under the catalysis of 98wt% to 99.5wt% concentrated sulfuric acid to produce high-octane gasoline blending component oil. Under the condition of excess olefin, the reactants are continuously fed, and at the same time, the mixture flowing out from the reactor can be separated to obtain an acid phase rich in catalyst concentrated sulfuric acid and an oil phase rich in alkylation products. Most of the acid phase products can be recycled, but as the reaction progresses, water and some a...

AI Technical Summary

Problems solved by technology

However, the existing waste acid pyrolysis regeneration process has the disadvantages of large equipment investment and high production energy consumption

From the flow process announced by CN100537416C, it can be clearly seen that the process flow is long and involves many operating units. The preparation of concentrated sulfuric acid by the contact-absorption method needs to carry out a series of pickling and impurity removal, demisting, and drying treatments on the cracking furnace gas, and the operating cost High operational complexity