SU767457A1 - Method for pyrodecontamination of waste liquor precipitates - Google Patents

Description

(54) METHOD FOR FIRE DECOMPOSITION OF SEDIMENTS

I

The invention relates to waste incineration methods and can be used in various industries and in public utilities.

Methods are known for the fire neutralization of mechanically dehydrated sewage sludge, including pre-drying the sludge with heat from the flue gases leaving the kiln, followed by burning and calcining the drying products in various types of kilns. In this case, in some cases, the precipitation is dried directly with heat from the gases from the furnace, followed by deactivation of the vapor-gas mixture in the furnace, and in others by air heated by heat from the gases from the furnace, followed by neutralization of the vapor-air mixture 1 and 2.

A disadvantage of the known methods is the high cost of the process, due to the fact that the steam-gas or vapor-steam mixture obtained by drying the dewatered sludge is introduced into the decontamination furnace with additional target fuel costs, and an oxidizer is additionally fed to the furnace for burning the resulting sludge. .

WASTEWATER

The closest in technical essence and achieved effect is the method of fire disposal of sewage sludge by their preliminary contact drying with air heated by heat.

5 flue gases leaving the furnace with the formation of dried precipitation and steam. mixture, and the subsequent combustion of the precipitated sludge and vapor-air mixture in the furnace using the target fuel and additional oxidizer 3.

10 A disadvantage of the known method is that it requires increased expenditures of the target fuel in connection with the supply of an additional oxidizer to the furnace for organizing the process of firing decontamination of dried sediments and burning of fuel.

 The purpose of the invention is to increase the economic efficiency of the process.

This goal is achieved by the fact that in the method of fire disposal of sewage sludge, including preliminary

20 contact area of dehydrated precipitation with air heated by the flue gas exhaust from the furnace, calcination in the furnace resulting from drying of the precipitation of the vapor-air mixture, burning dried precipitates and the target fuel in the furnace, before the vapor-air mixture is fed into the furnace, condensation removes moisture and then mixed with dried precipitates to form an air suspension.

The use of an air-vapor mixture as an oxidizer for the target fuel and dried precipitates, from which moisture has been partially removed, eliminates the cost of the target fuel for heating additional air, since this vapor-air mixture itself becomes an oxidizer and also eliminates the fuel consumption. heating the moisture contained in the vapor-air mixture, which leads to an increase in the economic efficiency of the decontamination process.

The implementation of the method is as follows.

Flue gases, waste w; s from the furnace, heat the air in the recuperator, which is fed to the contact drying of the sediment. As a result of drying, a dry precipitate and a vapor are formed. The air mixture contains: a, besides steam and air, highly volatile organic products and therefore needing E calcination. The vapor-air mixture is sent for drying, for example by condensation. In this case, part of the moisture from the vapor-air mixture is removed, the relative oxygen content increases, and the mixture becomes suitable for use as an oxidizing agent. The dried vapor-air mixture is mixed with the dry sludge from drying and forms a combustible aerosol suspension, which is sent to the kiln for incineration. This makes it possible to organize sustainable neutralization of toxic streams in the furnace at optimum temperatures.

Example. Mechanically dehydrated, sediments (with a humidity of 75 / o) in the amount of 5000 kg / h are introduced into the dryer. For drying, air heated to 600 ° C with the heat of flue gases from the furnace is used in an amount of 17,990 kg / h. As a result of drying the precipitates, dried precipitates are formed in the amount of 1,430 kg / h and the vapor-air mixture in the amount of 21,560 kg / h with a temperature of about 150 ° C, containing 17.5% oxygen.

The steam-air mixture is sent to the condenser to separate the vapor phase from it in the form of condensate in an amount of 3000 kg / h, and then in an amount of 18,500 kg / h with an oxygen content of 20.5% is fed to the mixture with 1430 kg / h of dried precipitation with the formation of combustible air suspension, which is introduced into the furnace. In case of liquid slag removal in the furnace (flue gas temperature 1500 ° C), fuel consumption is reduced by 2 times compared with the known methods due to a decrease in moisture in the steam-air mixture by 3000 kg / h and the use of the steam-air mixture as an oxidizing agent.

The implementation of the method makes it possible to reduce fuel consumption by using as the oxidant the combustible components of the dried vapor-air mixture and removing moisture from it, which requires additional fuel to be calcined, as well as improve the process of burning precipitates due to the supply of prepared aerospace to the kiln.

Claims (3)

1. The patent of Germany No. 2113887, cl. 24 d 2. 1971. 2. US patent number 3954069, class. 110-8, 1975. 3.Minz M.S. Technical schemes of sewage sludge incineration. “Plastics, No. 5, 1975, p. 59, fig. 4 (prototype).