METHOD FOR PREPARING SULFURIC ACID BY USING HYDROGEN SULFIDE

摘要

Provided is a method for preparing sulfuric acid by using hydrogen sulfide. The method comprises the following steps: (1) performing a reduction-oxidation reaction between an H2S feed gas and oxygen comprised in an oxygen-rich air to prepare SO2, controlling residual oxygen after the reduction-oxidation reaction step at a molar percentage of ≧2%; (2) cooling the product acquired in step (1) to a temperature between 390° C. and 430° C., and then performing a catalyzed oxidation reaction with oxygen, wherein the catalyzed oxidation reaction is performed in stages until the conversion rate of SO2 is ≧98.7% or the outlet concentration of SO2 is ≦550 mg/Nm3; and (3) cooling the product acquired in step (2) to a temperature ≧10° C. over the dew point temperature of H2SO4, then further cooling to a temperature between 60° C. and 120° C., collecting H2SO4 product, and subjecting the gas acquired after cooling to a coalescent separation before discharging directly into the atmosphere. Also provided is a heat exchanger, comprising a housing and several glass pipes, wherein the glass pipes are arranged within the housing along the direction of a long axis of the housing, arching between two lateral walls thereof, and used for circulating cooling medium; the adjacent glass pipes are connected head-to-tail, thereby forming at least one cooling medium flow path of unidirectional flow. The method for preparing sulfuric acid provides high removal efficiency of hydrogen sulfide, simple process flow, and allows for economic efficiency of apparatus and reasonable utilization of energy.

主权项

1. A method for preparing sulfuric acid by using hydrogen sulfide, characterized in that, comprising the following steps:
(1) performing a oxidation-reduction reaction between an H2S feed gas and oxygen comprised in an oxygen-rich air to prepare SO2, controlling residual oxygen after the oxidation-reduction reaction step at a molar percentage of ≧2%; wherein, if the molar percentage of H2S in the H2S feed gas is ≧8%, the oxidation-reduction reaction is a combustion reaction, the reaction temperature of which is ≧900° C.; if the molar percentage of H2S in the H2S feed gas is <8%, the oxidation-reduction reaction is a catalyzed reaction, the initiation temperature of which is ≧200° C.; (2) cooling the product acquired in step (1) to a temperature of 390° C.˜430° C., and then performing a catalyzed oxidation reaction with oxygen, wherein the catalyzed oxidation reaction is performed in stages until the conversion rate of SO2 is ≧98.7% or the outlet concentration of SO2 is ≦550 mg/Nm3; (3) cooling the product acquired in step (2) to a temperature ≧10° C. over the dew point temperature of H2SO4, then further cooling to a temperature of 60° C.˜120° C., collecting H2SO4 product, and subjecting the gas acquired after cooling to a coalescent separation before discharging directly into the atmosphere.