Method for increasing steam yield of heat recovery system in sulfuric acid production dry absorption section

Abstract

The invention provides a method for increasing the steam yield of a heat recovery system in a sulfuric acid production dry absorption section. The method is characterized in lower tower acid of a low-temperature absorption section (or a low-temperature absorption tower) of a heat recovery tower is independently sent into a drying or secondary absorption system; or an outlet of an evaporator is arranged on a serial acid pipeline of the drying or secondary absorption system; and the sulfuric acid is mixed with the lower tower acid which is not mixed with the high-temperature absorption section (or the high-temperature absorption tower), so that the lower tower acid temperature of the high-temperature absorption section (or the high-temperature absorption tower) is increased, the heat broughtby the sulfuric acid sent to the outside by the heat recovery system is reduced, and the steam yield of the evaporator of the heat recovery system is increased, thereby increasing the steam yield ofthe heat recovery system by about 10-25%.

Description

technical field [0001] The invention relates to the field of chemical industry, in particular to a method for increasing the steam production rate of a heat recovery system in a dry absorption section of sulfuric acid production. Background technique [0002] Modern sulfuric acid production mostly adopts a 2-to-2-suction production process, and the sulfuric acid produced by the upstream device contains S0 2 The process gas (or the air participating in the conversion reaction) first enters the drying system, uses concentrated sulfuric acid to remove water, and then enters the conversion section for a conversion to remove most of the SO 2 with O 2 reaction to generate SO 3 . Contains SO after one conversion 3 The process gas is sent to the heat recovery system of the dry suction section for primary absorption, and high-temperature sulfuric acid is used to absorb SO in the process gas 3 And recover the heat of absorption reaction to generate low-pressure steam. SO in proc...

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Problems solved by technology

[0004] SO after one conversion 3 The heat of reaction and dilution heat generated by absorbing sulfuric acid accounts for more than 70% of the heat generated in the entire dry suction section. The heat recovery system in the dry suction section adopts a high-temperature absorption process, using high-temperature sulfuric acid to heat low-pressure feed water to produce low-pressure steam, while drying and secondary The suction system adopts a low-temperature absorption process. After absorption, the acid temperature is low, and the heat of absorption cannot be utilized. The heat of absorption reaction is taken out of the process system through circulating water.

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