CS255053B1 - Method of heavy tar sludges treatment from coal gasification process - Google Patents

Abstract

Way treatment heavy of tar sludge from process gasification coal division on 'fixed and liquid phase distillation at temperature 180 to 360 ° C. FROM distilled and condensed liquid phase se immiscible folders separates on basis different speci # fical weight. Distillation residue se exploits energetically his combustion.

Description

The invention relates to a process for the treatment of heavy tar sludge from a coal gasification process comprising a solid phase and a liquid phase with an aqueous and organic component.

In the gasification of coal, condensates are formed by cooling the raw gas, which are divided according to density into light tar, phenolic water and heavy tar sludge.

Heavy tar sludge can be defined as a heterogeneous mixture of organic matter, some mechanical impurities and water.

At the same time, heavy tar sludge is not used in practice. They are deposited at the bottom of the storage tanks, from where they are continuously or one-time transported to a sludge and waste dump.

The construction of these landfill sites for heavy tar sludge is very costly, difficult to maintain, and the work is harmful to maintenance and operators. After the landfill has been filled, construction of other landfills must be ensured. It is also necessary to take into account the negative impact on the environment in the vicinity of landfills of heavy tar sludge, which is manifested by permanent evaporation of harmful vapors of odorous substances.

The direct combustion of heavy tar sludge or its return to the coal gasification plant has not been fully proven in practice and is not known to be in continuous operation.

The foregoing invention relates to a process for the treatment of heavy tar sludge which comprises distilling it at a temperature of 180 to 360 ° C. During distillation, the heavy tar sludge is separated into a solid phase with a distillation residue of organic matter and a vapor phase. After cooling and condensing, the vapor phase is separated into an aqueous and organic component on the basis of different specific weights.

The products obtained according to the above process can be used for energy (loose distillation residue), the organic components of the distillate can be used as raw materials in the chemical industry (the possibility of processing as light tars of pressurized gas plants).

The water component of the distillate can be treated in the technological process of waste water de-gasification, which is an essential part of any coal gasification operation.

Example of specific use:

During pressure gasification of brown coal, the produced gas also contains water vapor, tar vapors and small particles of coal charge or ash. Subsequent cooling of the produced gas creates condensate, which is divided into individual components - tar, phenolic water and heavy tar sludge.

Heavy tar sludge contains water, mechanical particles and industrial organic substances.

Table 1 shows the composition of heavy tar sludge as an example.

Table 1- Composition of heavy tar sludge (example from brown coal pressure gasification).

Mechanical impurities 19.4 % hm Asphaltenes 11.0 % hm Acid-curing oils 4.3 % hm Phenols 7.5 % hm Alkaline content of organic substances 0.9 % hm Neutral content of organic substances 27.7 Water 29.2

The tar and phenolic waters are further processed, heavy tar sludge settles on the bottom of the storage tanks, from where it is continuously or one-time transported to the tar sludge dump.

According to the process of the invention, the heavy tar sludge is distilled under constant agitation at a temperature of 180 to 360 ° C in a simple distillation vessel without internal packing. A stirrer is located inside the distillation vessel, which also serves as a wall scraper.

The installation of vapors from the distillation vessel prevents the mechanical particles from flowing. In the lower part, the distillation vessel has a solid phase outlet.

In the upper part of the distillation vessel there is an opening for the entry of heavy tar sludge.

The distilled vapor phase condenses in the condenser and is discharged to the condensate collection, where the content is separated into specific organic and aqueous phases according to specific weights, the phases are separated separately for further use.

Table 2 (atmospheric pressure, 250 ° C) gives an overview of the composition of the brown coal pressure gasification distillate.

Table 2 - Composition of heavy tar sludge distillate (eg from pressure coal gasification).

Phenols 11.5 % hm Alkaline content of organic substances 1.4 % hm Neutral content of organic substances 42.4 % hm Water 44.7 % hm

With the addition of a neutral proportion of organic substances:

Alkanes 11.2 % hm Uncondensed cycloalkanes 7.3 % hm Condensed cycloalkanes 13.9 % hm Alkylbenzenes 13.9 % hm Indanes, tetralins 14.2 % hm Alkylnaphthalenes 22.1 % hm Acenaphthenes, diphenyls 13.6 % hm Benzothiophenes 3.8 % hm

The distillation residue (34.7 wt%) has a gross calorific value of 29.9 MJ / kg.

The whole equipment is adapted to the possibility of cleaning the interior spaces by technological steam

The organic component can be further processed by energetic or technological process usual for use of light tars by pressure gasification of brown coal.

The proposed treatment of heavy tar sludge has a major benefit in improving the environment and utilizing industrial and energy raw materials.

Claims (1)

Process for treating heavy tar sludge from a coal gasification process characterized in that the liquid phase of heavy tar sludge is distilled off at a temperature of 180 to 360 ° C and from the resulting distilled, condensed liquid phase the immiscible components are separated on the basis of different specific weights and by its combustion.