Purification of gases

TECHNOLOGY

 

The problem of air pollution.

Air pollution is a big problem that threats the environment. Very dangerous are volatile organic compounds (VOC). VOC is thought to determine the level of ozone, hydrogen peroxide, nitrate acetylene peroxide (and in the consequence of atmosphere changes) aldehydes and ketones  concentration in  the air. VOC are pairs of organic substances, that are liquids or solids in normal conditions. Methane, glycols, phenols, aromatic compounds C>10 are excluded from this group. For the reason of gradationally harmfulness of VOC it has been divided into classes (tab.1)

 

Tab. 1. Division of VOC into classes according to their harmfulness.

 

 

VOC class
The most important	trimethylbenzene, meso- & para- xylenes
Very important	akilobenzene aldehydes
Less important	formaldehydes ethanol esters (for example methyl formate)
Little important	benzene methanol chlorinated hydrocarbons

 

 

Sources of VOC forming could be divided in two groups according to human factor:

 

Naturals:

• Forest fires;
• Volcanoes;
• Geysers;
• Earth gas;
• Vegetation processes of some organisms;
• Assimilation processes.

 

Anthropogenic:

• Processes of fuel mining and combustion;
• Crude oil refining;
• Metallurgy;
• Organic chemistry industry;
• Solvents usage and production;
• Food industry;
• Agriculture;
• Road, air and sea transport;
• Solid wastes utilization.

 

Methods of elimination the VOC emission to the atmosphere:

• Absorptive methods – gas impurities are absorbed by fluid (an absorbent). Gas component reacts with fluid and  produce non-volatile products. Absorption is made in scrubbers.
• Adsorptive methods – effect of VOC stoppage on the solid body’s (adsorbent) surface is being used in this method. As an adsorbent is usually used porous substance that has well developed complete surfaces and appropriate distribution of pores’ size, for example active carbon.
• Combustion methods – converting VOC into neutral substances or less toxic than primary. Combustion could be thermal or catalytic.
• Condensation methods – converting gas into liquid as a result of diversification of temperature and pressure (cooling).

 

In the original solution made by the ATON-HR company gases are forced into process chamber filled with ceramic profiles that is high temperature resistant and absorbs microwaves. Ceramic profiles are heated to a temperature of 900°C-1400°C and causes turbulent flow of cleaned gases and heats it intensively at the same time. In these controlled conditions all organic impurities are effectively combusted and it is rendered dusts (asbestos dusts also) harmless. System which is here described allows also to very effective removal of odors.

Technical parameters:
 

SUPPLY	3 x 400V (50Hz)
MAX. POWER INPUT	50kW
MICROWAVES INSTALL POWER	36kW (f=2450MHz)
PRODUCTIVITY	Do 300m3/h
TEMPERATURE INSIDE REACTOR DRUM	1200°C

 

 Fig. 1. ATON 2 MOS reactor.

 

MICROWAVES ASSIST AFTER COMBUSTION OF POLLUTIONS IN GASES

ELIMINATING PERMANENT CONTAMINATIONS FROM GASES BY MEANS OF A ROTATING GAS PLASMA

ATON 2 MOS mobile reactor is to after-burning organic compounds (hydrocarbons) and other volatile chemical substances that are emitted during typical combustion processes (for example in incinerating plants). Organic compounds treated by high temperature (about 1000°C) are being oxidized in the presence of the ceramic balls which are strongly absorbing the microwaves. 

 

Fig. 2. Construction of ATON 2 MOS reactor with heat exchanger.

 

 

Fig. 3. ATON 2 MOS prototyp reactor.

 

To confirm effectiveness of method whichhas been worked out in the ATON-HT company, we ordered research in outer institution. As a result of measurements it has been obtained a  decreased contents of VOC in gases getting out of reactor in comparison with getting in gases. Majority of measuring device printouts showed that VOC value was below detectability level.

 

ROTATING ARC PLASMA – purifying gases

The essence of this original method of purifying gases is a preliminary process of heating the purified gases in the input chamber to the temperature of at east 400 ºC - 800ºC by means of conventional gas or oil burners, and then a quick thermal decomposition of all chemical substances contained by the output gases stream, together with its partial dissociation and ionization during a forced passing through the sphere of an aroused curve plasma.