CN102921274A - Method for treating ammonia tail gases during production of paraquat - Google Patents

Abstract

The invention discloses a method for treating ammonia tail gases during the production of paraquat. The method includes following steps that, step one, the ammonia tail gases discharged after the paraquat is produced are fed to more than two absorption towers which are connected in a series mode, the discharged ammonia tail gases are one or more of a coupling ammonia tail gas, an oxidation ammonia tail gas, a leaked ammonia tail gas or an evaporation ammonia tail gas, water serving as a medium is added for absorbing the ammonia tail gases to obtain diluted aqua ammonia and a small quantity of the ammonia tail gases after absorption, the small quantity of the ammonia tail gases enter tail gas absorption towers to be recycled, and heat is brought out by an outer circulation condenser during an absorption process; and step two, the diluted aqua ammonia after absorption in the step one is distilled and condensed to be liquid ammonia for circular recycling, and waste water is discharged. According to the method, a recycling technology for optimizing ammonia is adopted during the production process of the paraquat, by means of the principle that the ammonia is freely soluble in water, the water is used as an absorption solvent to dissolve and absorb the ammonia tail gases produced during the production of the paraquat, and the mixture is distilled and recycled to be the liquid ammonia for circularly recycling the ammonia so that production costs are reduced, environment is protected, and market competition of the paraquat is improved.

Description

Ammonia method for treating tail gas during paraquat is produced

Technical field

The present invention relates to the technology that the ammonia tail gas recycle is utilized in the paraquat technique, refer to particularly it is ammonia method for treating tail gas during a kind of paraquat is produced.

Background technology

Paraquat is that a kind of quick-acting going out given birth to tagging property highy potent herbicide, has good interior suction, conductive performance.Domestic cyanamide process production technology obtains important breakthrough; its technique has many good qualities; but the ammonia vent gas treatment problem that produces in its building-up process fails to be solved; adopt in the cyanamide process explained hereafter paraquat process, the regulation effect of ammonia tail gas has very large meaning to environmental protection and reduction process costs.

Summary of the invention

Purpose of the present invention is exactly that the demand of a kind of energy satisfying the market to the paraquat aqua product will be provided, and can reduce liquefied ammonia consumption simultaneously, environmental contamination reduction, ammonia method for treating tail gas during the paraquat of reduction paraquat production cost is produced.

For achieving the above object, ammonia method for treating tail gas during paraquat provided by the present invention is produced, it comprises the steps:

(1) produces the absorption tower that the ammonia tail gas that discharges behind the paraquat is delivered to the above series connection of two-stage, the ammonia tail gas that discharges is coupling ammonia tail gas, oxidation ammonia tail gas, let out among ammonia ammonia tail gas or the vaporized ammonia tail gas any or several, add water as medium with absorbing ammonia tail gas, weak aqua ammonia after being absorbed and a small amount of ammonia tail gas, a small amount of ammonia tail gas enters to be recycled after tail gas absorber absorbs, and the heat in the absorption process is taken out of through the outer circulation condenser;

(2) compression condensation after the weak aqua ammonia distillation after absorbing in the step (1) is become the liquefied ammonia recycle and reuse, and discharge waste water.

As preferred version, produce the ammonia tail gas that discharges behind the paraquat in the described step (1) and deliver to the absorption tower of three grades of series connection with absorbing ammonia tail gas.

The invention has the advantages that: the method is to have taked to optimize the recovery application technology of ammonia in the paraquat production process; utilize ammonia principle soluble in water to make lyosoption with water; ammonia tail gas during the solution absorption paraquat is produced; and Distillation recovery becomes liquefied ammonia to reach the recycling of ammonia; thereby reduce production costs; protection of the environment has improved the market competitiveness of paraquat.

Description of drawings

Fig. 1 is ammonia solvent recovery technology from vent gas flow chart of the present invention.

The specific embodiment

The present invention is described in further detail below in conjunction with the drawings and specific embodiments.

As shown in the figure, produce the former medicine of paraquat by the raw material pyridine through alkylation, coupling, filtration, oxidation, enter modulating process behind the former medicine sedimentation of the paraquat certain hour, add auxiliary agent and other production auxiliary materials and produce qualified paraquat aqua.Produce the coupling ammonia tail gas, the oxidation ammonia tail gas that discharge behind the paraquat aqua, let out the absorption tower that ammonia ammonia tail gas and vaporized ammonia tail gas are all delivered to three grades of series connection, add water as medium with absorbing ammonia tail gas, weak aqua ammonia after being absorbed and a small amount of ammonia tail gas, a small amount of ammonia tail gas enters to be recycled after tail gas absorber absorbs, and the heat in the absorption process is taken out of through the outer circulation condenser; Compression condensation becomes the liquefied ammonia recycle and reuse after the weak aqua ammonia distillation after the absorption, and discharges waste water.

Claims (2)

1. ammonia method for treating tail gas during a paraquat is produced, it comprises the steps:

(1) produces the absorption tower that the ammonia tail gas that discharges behind the paraquat is delivered to the above series connection of two-stage, the ammonia tail gas that discharges is coupling ammonia tail gas, oxidation ammonia tail gas, let out among ammonia ammonia tail gas or the vaporized ammonia tail gas any or several, add water as medium with absorbing ammonia tail gas, weak aqua ammonia after being absorbed and a small amount of ammonia tail gas, a small amount of ammonia tail gas enters to be recycled after tail gas absorber absorbs, and the heat in the absorption process is taken out of through the outer circulation condenser;

(2) compression condensation after the weak aqua ammonia distillation after absorbing in the step (1) is become the liquefied ammonia recycle and reuse, and discharge waste water.

2. ammonia method for treating tail gas during paraquat according to claim 1 is produced is characterized in that: produce the ammonia tail gas that discharges behind the paraquat in the described step (1) and deliver to the absorption tower of three grades of series connection with absorbing ammonia tail gas.

Images