Synchronous heat exchange gas absorption tower and nitric oxide absorption and concentration process

Abstract

The invention discloses a synchronous heat exchange gas absorption tower, which is a bubble-cap tower. The bottom of the tower is provided with a liquid outlet and a gas inlet; the top of the tower is provided with a tail gas outlet and an absorption liquid outlet; 1 to 3 layers of heat exchange coils are arranged between bubble caps of each layer of tower tray; inlets and outlets of the heat exchange coils are directly communicated with the outside of the tower; and a heat transfer medium flows in the heat exchange coils. The invention also discloses a nitric oxide absorption and concentration process by employing the synchronous heat exchange gas absorption tower. The process comprises the following steps of: mixing a NOX-containing waste gas and air according to the concentration and class of the waste gas in a certain ratio, introducing the mixed gas from the bottom of the absorption tower, introducing water or dilute nitric acid serving as an absorber from the top of the tower, performing countercurrent or crosscurrent contact reaction of the mixed gas and the absorber on each stage of filler or tower plate, timely bringing away reaction heat by using cooling water in the heat exchange coils on each stage of filler and tower plate, ensuring that the NOX concentration in the exhaust tail gas on the top of the absorption tower is 150ppm and the rate is 1kg / h, and obtaining nitric acid with the concentration of 35 to 58 percent at the bottom of the absorption tower.

Description

technical field [0001] The present invention relates to gas absorption tower, and NO X Environmental protection of waste gas. Background technique [0002] Nitrogen oxides (mainly referring to NO and NO 2 , commonly known as NOx) will form yellow or brown smog in the air, commonly known as "yellow dragon", which is one of the important sources of air pollution at present. NO X Exhaust gas will not only cause acid rain and acid fog, but also destroy the ozone layer, causing serious harm to the natural environment and human production and life. Processes such as the nitric acid industry, fuel combustion, and motor vehicle exhaust release large amounts of nitrogen oxides. According to incomplete statistics, in 2005, my country's nitrogen oxide emissions were as high as 22.2 million tons, ranking among the highest in the world. The air pollution and acid rain caused by this are serious, and the economic losses are huge, seriously restricting the sustainability of my country'...

AI Technical Summary

Problems solved by technology

The patent ZL200610039814.1 authorized by the inventor of this patent proposes a complete set of process for treating and recovering nitrogen oxides, including absorption, bleaching, and concentration processes. This set of process has been used in enterprises producing adipic acid, oxalic acid, and DNT (all adopt Nitric acid is used as an oxidant, and after the gunpowder smoke is absorbed, it becomes high-concentration nitric acid for recycling) successfully applied, but there are still some defects. Increased power consumption and operating costs; on the other hand, since the heat of reaction can only be extracted after the absorption liquid flows through a section of packing, the removal of the heat of reaction is delayed, resulting in a large temperature difference between each section of packing, and the reaction rate is uncontrollable , the absorption efficiency is not uniform, which requires more theoretical stages of absorption to meet the process requirements, making the process longer, usually requiring 2 to 3 absorption towers

Images