Waste heat utilization method for flue-gas acid making process

Abstract

The invention discloses a waste heat utilization method for a flue-gas acid making process. Half of SO2 flue gas is mixed with air, the mixture is heated by a first heat exchanger and a fore heat exchanger and then enters a fore bed layer of a sulfur dioxide converter, exit gas is subjected to heat exchange with the fore heat exchanger and then is mixed with the other half of SO2 flue gas, and then, the mixture enters a first-segment bed layer; exit gas of the first-segment bed layer is subjected to heat exchange with a first steam superheater and then enters a second-segment bed layer; exit gas of the second-segment bed layer is subjected to heat exchange with a third heat exchanger and then enters a third-segment bed layer; exit gas of the third-segment bed layer is subjected to heat exchange with a second steam superheater, then, one part of the exit gas is subjected to heat exchange with the first heat exchanger, and the other part of the exit gas is subjected to heat exchange with a second heat exchanger and then enters a high-temperature absorption tower; exit gas of the tower is heated by a fourth heat exchanger and the third heat exchanger and then enters a fourth-segment bed layer; exit gas of the fourth-segment bed layer is subjected to heat exchange with a third steam superheater and the fourth heat exchanger and then enters a final absorption tower. According to the method, the process adaptability is extensive, the operation is convenient, the running is reliable, and the waste heat utilization ratio is high.

Description

technical field [0001] The invention belongs to the technical field of inorganic chemical industry, and in particular relates to a method for utilizing waste heat in the process of making acid from flue gas. Background technique [0002] At present, in the field of acid production from non-ferrous metal oxygen-enriched smelting flue gas, high-concentration SO2 has been put into industrial production 2 Flue gas conversion technologies mainly include BAYQIK technology of Bayer Company of Germany, LUREC technology of Out-0tec and pre-reformation technology of Mengmok Company of the United States. These three techniques can handle φ(SO 2 ) ≥ 14% of the flue gas, and compared with the conventional conversion process, the equipment specification is reduced, the operating cost is reduced, and the waste heat recovery rate is improved. Because sulfur dioxide is converted into sulfur trioxide, multi-stage conversion is required. In the conversion and heat exchange process, the cold ...

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Problems solved by technology

The heat exchange processes of the above three high-concentration sulfur dioxide conversion technologies have their own characteristics. Although their total conversion rate and absorption rate are high, they have high requirements for equipment structure design, complex heat exchange process, and high risk of failure of waste heat recovery devices (waste heat boiler and economizer, etc.), unreasonable use of heat energy, etc.

At the same time, affected by flue gas SO 2 Restricted by factors such as concentration adaptability, catalyst performance and dosage, gas distribution form, and ease of operation and control, in industrial production, the above three technologies all have bottlenecks that affect the long-term and full-load stable operation of equipment to varying degrees.

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