Emissions in the production of cement

Production of cement is very energy-intensive process in which large amounts of materials are processed. Most of the energy consumed is thermal energy, entering into the process with fuels. The main outputs from the thermal part of the process are clinker and CO2, but there are also certain other emissions, such as: carbon monoxide, nitrogen oxides, sulphur dioxide, dust and other substances in small quantities. CO2 is primarily a result of calcium and magnesium carbonate decomposing into oxides and CO2. It is also a result of combustion of primary and alternative fuels. Flue gases leave the system through the main chimney.

In other parts of the production process such as milling, crushing, preparation of the row mix, storage, etc usually emissions of particulate matter occur.

Modern technological processes are arranged in a way that environmental impacts are minimized, so all places of possible release are equipped with filters for particulate matter and for other pollutants. In the case that such devices and monitoring of the process is not efficient enough to reduce emission values to prescribed values, other techniques must be built-in for cleaning flue gases. Such techniques are described in reference documents on best available techniques (BAT), which is a part of requirements for IPPC (Integral Pollution, Prevention and Control) permit. IPPC permit can be obtained only by a cement plant, which is in accordance with the requirements of the regulation and achieve emission values that are provided by best available technique.

There are no waste materials in the cement production since all the products formed during the process stay inside the process and are incorporated into the final product.

It is very important for cement plants to perform all prescribed emission monitoring, required by the regulation. Emissions measurements are regulated by several rules that apply to different conditions of operating. It is important that the emission parameters, resulting in amounts greater than provided for in the air mass flow, are measured continuously. Authorized contractors can measure other parameters in the prescribed frequency, for example once or twice a year.

CO2 emission reduction

Already in 2005 the European Community set a program to reduce greenhouse gas emission through the introduction of trading in emission rights. This is the way to stimulate big CO2 “producers” to reduce emissions. Cement plants can do this with continuous investment in new technologies, which enable greater efficiency, and with usage of wastes as alternative fuels, particularly biomass which replaces the natural resources of energy.

Cement plants as the major “producers” of greenhouse gases are committed to BAT Technologies, this means Best Available Technologies, prescribed by the IPPC permit (Integral Pollution Prevention and Control) which is a condition for cement plants to operate.