CZ306526B6 - A device for drying and combustion of fuels with removal of NOx substances in combustion products - Google Patents

Abstract

The device for drying biomass and combustion of fuels with removal of NOx substances in combustion products contains a boiler having the deNOx band (11), and further comprises a unit for volatilization of gases from biomass, out of which there leads the outlet (9) of the volatilized gas to the deNOx band (11) of the boiler and the outlet (2) of the biomass after volatilization to the boiler.

Description

Equipment for drying and combustion of fuels with removal of NO _X substances in flue gases

Field of technology

The invention relates to an apparatus for drying biomass and burning fuels using an ammonia-containing gas mixture in order to carry out a so-called selective catalytic reduction and / or selective non-catalytic reduction to remove NO _X from the flue gas by volatilizing ammonia from the biomass.

Prior art

During the combustion of solid biomass, but also other fuels, the presence of nitrogen in the fuel and the nitrogen contained in the air supplied to the combustion chamber causes emissions of nitrogen oxides (NO _X ). These can be removed, for example, by selective catalytic reduction technology or by selective non-catalytic reduction technology. In the case of both processes, regular dosing of the reducing agent is necessary for the correct process of reduction of these substances. The most common reducing agent used is industrially produced ammonia or urea. This makes operation economically more expensive.

The present solution provides a fuel combustion plant with the removal of NOx substances in the flue gas, which allows cheap operation with a minimum of waste.

When drying biomass containing ammonium nitrogen, for example a separation from biogas plants, ammonia volatilizes. It must be collected to prevent damage to the environment.

The essence of the invention

The present invention relates to an apparatus comprising a boiler having a denox zone, a unit for volatilizing gases from biomass, from which the volatilized gas is discharged to the denox zone of the boiler, and biomass output after volatilization, e.g. to a boiler or for other uses for growing mushrooms or plants.

The biomass gas volatilization unit may include a biomass inlet, a heated region for volatilization with a preheated air supply from the preheated air source, and a volatilized gas outlet and a biomass outlet after volatilization.

The source of preheated air can be an exchanger heating the air with heat from the flue gases from the boiler. The boiler includes a combustion zone with a grate and a denox zone, where NOx is removed. It also usually includes a flue gas exchanger and a chimney.

The combustion of fuel in this plant includes the step of purifying the flue gas from the fuel combustion with selective catalytic reduction (SNR) or selective non-catalytic reduction (SNCR) technology to remove NO _X substances in the flue gas, using a mixture of ammonia-containing gases prepared as a reducing agent. volatilization from biomass.

The fuel dosed to the boiler grate can be, for example, solid biomass, coal or other solid fuels.

Biomass with a high content of ammoniacal nitrogen, such as digestate or separated digestate, sewage sludge, manure, etc., can be used to prepare the gas mixture containing ammonia.

The gas volatilization unit can be a dryer, for example a belt, drum or fluid bed dryer, and the waste heat generated by the combustion of the fuel can be used for drying. The resulting air. i.

it contains the necessary ammonia and water vapor. This gas mixture is fed to a zone for dosing the reducing agent in the combustion process and is used to reduce NO _X to form N ₂ .

The biomass after volatilization can then be burned, for example. Due to the lower water content, the treated biomass has a higher calorific value and due to the low nitrogen content less NOx particles are formed.

Explanation of the drawing

Giant. 1 shows schematically a device according to an exemplary embodiment of the invention.

Example of an embodiment of the invention

The device comprises a boiler having a denox zone 11, a unit for the volatilization of gases from the biomass, from which the volatile gas outlet 9 leads to the denox zone 11 of the boiler, and a biomass outlet 2 after volatilization to the boiler.

The biomass gas volatilization unit may comprise a biomass inlet 1, a heated volatilization area with a preheated air inlet 3 from the preheated air source, and a volatilized gas outlet and a biomass outlet 2 after volatilization.

The source of preheated air can be an exchanger 4 heating the air with heat from the flue gases from the boiler.

The boiler comprises a combustion zone with a grate 7 and a denox zone 11, where NOx is removed. Air is introduced into the boiler through the inlet 6. Furthermore, the boiler comprises a flue gas exchanger 12, from which heat energy can be transferred via an inlet 5 to the exchanger 4, and a chimney 3. Ammonia from an outlet 9 is introduced into the denox zone 11 via an outlet 10.

When burning biomass after volatilization, this biomass is fed by a biomass dispenser 8 to the boiler.

Claims (5)

PATENT CLAIMS An apparatus for drying biomass and burning fuels with the removal of NO _X substances in the flue gas, comprising a boiler having a denox zone (11) where NO _X substances are removed, characterized in that it further comprises a unit for volatilizing gases from the biomass, discharge (9) of volatilized gas to the denox zone (11) of the boiler and outlet (2) of biomass after volatilization to the boiler. Apparatus according to claim 1, characterized in that the biomass gas volatilization unit comprises a biomass inlet (1), a heated volatilization area with a preheated air inlet (3) from the preheated air source (4), and a volatilized gas outlet and outlet ( 2) biomass after volatilization. Device according to claim 1, characterized in that the gas volatilization unit is a dryer, preferably a belt, drum or fluid bed dryer. Device according to claim 2, characterized in that the source of preheated air is an exchanger (4) for heating air with heat from the flue gases from the boiler. -2EN 306526 B6 Apparatus according to claim 1, characterized in that the boiler further comprises a combustion zone with a grate (7).