Toxic Emissions from Solid Fuel Combustion in Small Residential Appliances

Introduction

Combustion of solid fuels is a source of pollutant emission to the atmosphere. Low combustion efficiency (usually not exceeding 50% average per year), poor fuel quality and no or little cleaning of exhaust gasses result in higher emissions. Especially the combustion of coal either in residential heating appliances (i.e. stoves, furnaces) or boilers of low power is widely considered to be of the most pollutant emitting sources.

Research carried out in the past few years proves that besides significant emission of CO, SO₂, NO_x and particles, these sources are also responsible for significant amount of organic pollutants (TOC), including polycyclic aromatic hydrocarbons (PAH), dioxins and furans – PCDD/F, and VOC such as aliphatic hydrocarbons, benzene and its derivatives (BTX), aldehydes and ketones, but also phenol and its alkyl derivatives, heterocompounds of nitrogen and sulphur etc., and heavy metals 1, 2, 3.

The negative impact from the use of low efficiency heating devices is multiplied by the combustion of fuels of poor quality with significant sulphur and ash contents, low calorific value and coal sludge. This is especially true for the Central and Eastern European Countries (CEEC) where the cold climate, ease of access to coal and poor economic conditions make the heating of residences by coal an attractive option. At the same time biomass becomes a more and more popular fuel used in residential sector, due to the strategy to achieve reduction of CO₂ in same countries. But also installations burning biomass are often characterized by higher emissions of particulates and related pollutants.