CN1141348C - Preparation method of alkaline oxygenated vegetable tannin extract for gas desulfurization and purification - Google Patents

Abstract

The present invention relates to a preparation method of alkaline oxidized tannin extract for gas desulphurization and purification. The present invention is characterized in that the aqueous solution of thermosol valonea extract is added in a reaction vessel to carry out circulation reflux heating, alkali is added in the reaction vessel to carry out oxidation by introducing air, manganese sulphate and ferrous sulfate are added in the reaction vessel, and the materials are made into a powdery product by concentration and drying. The product has the advantages of high activity, reasonable colloidality, less use level, low cost, simple preparation method and stable technology. The tannin extract is suitable for gas desulphurization in nitrogenous fertilizer plants, gas plants and coke-oven gas plants, and is also suitable for H2S elimination in other gases.

Description

Preparation method of alkaline oxidation tannin extract for gas desulfurization and purification

(I) technical field

The invention relates to a preparation method of alkaline oxidation tannin extract for gas desulfurization and purification, belonging to the field of chemical industry.

(II) background of the invention

Tannin extract desulfurization is widely applied to the industries of medium and small nitrogen fertilizer plants, coke oven gas plants, coal gas plants, environmental protection and the like, and mainly aims at removing harmful components H in gas₂S is removed through the alkaline tannin extract liquid, the tannin extracts used in the original factories are self-provided and self-used by manufacturers, the preparation conditions are unstable, most products have low activity, large dosage and strong colloid property, and are easy to foam, so that the production process is unstable, and the economic benefit is not good.

Disclosure of the invention

The task of the present invention is to overcome the drawbacks and drawbacks of the prior art and to provide a method for preparing an alkaline oxidized tannin extract for gas desulfurization and purification, so as to produce a standardized tannin extract with good quality and small dosage, which makes the production process more stable and improves the economic benefits.

The task of the invention is realized by the following technical scheme:

a process for the preparation of an alkaline oxidized tannin extract for gas desulfurization, characterized in that it is carried out according to the following steps:

a) will contain 30-40kg/M³Adding hot-soluble rubber-bowl tannin extract aqueous solution of dry gum into a reaction kettle, performing circulating reflux by using a pump, heating to 80-95 ℃, introducing air, and ensuring that the strength is 15-20m³/m²Adding sodium hydroxide or sodium carbonate of 10% of the weight of the dry glue, and reacting for 25-30 hours;

b) adding manganese sulfate and ferrous sulfate, wherein the adding amount of the manganese sulfate is 2% of the weight of the dry glue, and the adding amount of the ferrous sulfate is 0.5% of the weight of the dry glue, and continuously reacting for 2-3 hours;

c) after the reaction is finished, concentrating and drying the materials to prepare powder, namely the product.

The thermosol oak cup tannin extract is a powdery product which is extracted from oak fruit shell, namely oak cup, by hot water and dried, and has a tan appearance and the following components: tannin 68-71%, external tannin 20% +/-, pectin 5% +/-and a small amount of glucose, insoluble substance 3% +/-, it can be dissolved in water without limit, has an amorphous structure, is a complex mixture consisting of a plurality of macromolecular phenol derivatives with similar structures, tannin extract can not be directly used for gas desulfurization, tannin can be degraded only by long-time oxidation of tannin in tannin, thermokalite and air, activity is enhanced, phenol state structure is further oxidized into quinone state structure, meanwhile colloidal particles are dissociated, partial colloid is destroyed, surface activity is converted into non-surface active substance so as to defoam, and the tannin extract with higher activity and certain colloidal property can be used for desulfurization.

The tannin extract desulfurization is wet-type binary oxidation desulfurization, in which alkaline oxidation degradation products of tannin extract are used as an intermediate oxygen carrier, and a complexing agent of alum is used to prepare an aqueous solution with alkali and alum, and gaseous hydrogen sulfide is absorbed and converted into elemental sulfur.

During production, the alkaline oxidation tannin extract is added into a gas desulfurization device, water is added, alkali is dissolved, vanadium pentoxide is dissolved to prepare a desulfurization solution, and hydrogen sulfide in gas reacts as follows:

NaHS is then reacted with NaVO₃The reaction is as follows:

，

Na₂V₂O₅then reacts with the alkaline oxidation tannin extract of the invention, and the reaction is as follows:

while

Thus completing the whole process of the desulfurization reaction.

Compared with the prior art, the invention has the following advantages and effects due to the adoption of the technical scheme:

a) the tannin extract activity prepared by the method of the inventionGood, moderate in glue property, small in dosage and can reduce V₂O₅The dosage of the sulfur-containing material improves the product quality, and simultaneously, the sulfur-containing material can also recover high-quality elemental sulfur, thereby reducing the pollution to the atmosphere.

b) The preparation method is simple, the process flow is stable, and the operability is good.

(IV) detailed description of the preferred embodiments

Example 1

Taking the mixture containing 30kg/M³Hot-melt oak cup tannin extract aqueous solution 1M of dry gum³Adding into a reaction kettle, performing pump circulation reflux, heating to 80 deg.C, introducing strong air with strength of 20m³/m²Adding 3kg of sodium hydroxide, reacting for 30 hours, adding 0.6kg of manganese sulfate and 0.15kg of ferrous sulfate, continuing to react for 2 hours, and then drying to prepare a powdery product, wherein the product is used in a nitrogen fertilizer plant or a gas plant according to a conventional method, the desulfurization rate can reach more than 99.8 percent, and the elemental sulfur product can be recovered.

Example 2

Taking the mixture containing 35kg/M³Hot-melt oak cup tannin extract aqueous solution 1M of dry gum³Adding into a reaction kettle, performing circulating reflux by using a pump, heating to 90 ℃, introducing strong air, wherein the strength of the air is 18m³/m²Adding 8.75kg of sodium bicarbonate, reacting for 28 hours, adding 0.7kg of manganese sulfate and 0.175kg of ferrous sulfate, continuing to react for 2.5 hours, and then drying to prepare a powdery product, wherein the product is used in a nitrogen fertilizer plant or a gas plant according to a conventional method, and the desulfurization rate can reach 99.8 percentThe elemental sulfur product can be recovered.

Example 3

Taking the mixture containing 40kg/M³Hot-melt oak cup tannin extract aqueous solution 1M of dry gum³Adding into a reaction kettle, performing pump circulation reflux, heating to 95 deg.C, introducing strong air with strength of 15m³/m²Adding 4kg of sodium hydroxide, reacting for 25 hours, adding 0.8kg of manganese sulfate and 0.2kg of ferrous sulfate, continuing to react for 3 hours, and then drying to prepare a powdery product, wherein the product is used in a nitrogen fertilizer plant or a gas plant according to a conventional method, the desulfurization rate can reach more than 99.8 percent, and the elemental sulfur product can be recovered.

Claims (1)

1. A process for the preparation of an alkaline oxidized tannin extract for gas desulfurization, characterized in that it is carried out according to the following steps:

a) will contain 30-40kg/M³Adding hot-soluble dry extract of oak cup tannin extract into reactor, refluxing with pump, heating to 80-95 deg.C, introducing air, and making its strength be 15-20m³/m²Adding sodium hydroxide or sodium carbonate of 10% of the weight of the dry glue, and reacting for 25-30 hours;

b) adding manganese sulfate and ferrous sulfate, wherein the adding amount of the manganese sulfate is 2% of the weight of the dry glue, and the adding amount of the ferrous sulfate is 0.5% of the weight of the dry glue, and continuously reacting for 2-3 hours;

c) after the reaction is finished, concentrating and drying the materials to prepare powder, namely the product.