The cement kiln: a safe and performing incinerator

Emile Rigo

Lafarge Romcim

Western European cement plants have, for many years, incinerated industrial wastes and used the resulting by-products as raw materials.

This leads to an improved environment protection and energy saving (by saving oil, coal or gas).

Using the industrial wastes as raw materials in the cement kilns is an integrated part of the environmental protection policy of Lafarge Group (policy reflected in the financial commitment too: 65 M $ for environmental protection in 1998, of which 7.2 M $ in Romania).

The cement kiln, because of its functional characteristics and a perfect burning control, is considered today the best incinerator.

The technical process is described in this presentation together with the principal experiments and the beginnings of the incineration process in Romania.

Why the cement kiln?

• A perfect control of technology;

• Bringing an intelligent, reliable and economic solution for industrial waste management to the countries where Lafarge is present;

• Lafarge Group adaptation and strong will facing the energy-related stakes of our time;

• Integration into a European wastes disposal system. Due to the very high temperature (2000 0 C - the temperature of the flame, and 1450 0 C - the temperature of the material), to the oxidative conditions and to the basic medium in the kiln, after 2 seconds at more than 800 0 C, the organic molecules are destroyed in a proportion of 99.940 - 99.999%;

• There is no residual waste; all the wastes are fixed into the clinker, into the cement, then into the concrete;

• There are no emissions of supplementary gases, because the kiln works as an efficient trap.

Waste types

1. Liquid wastes:

Energetic:

• oil residues, solvents, chemical industry production wastes (butanol, hexenal), methyl esters, distillation wastes and oils.

Less or not at all energetic:

• cutting fluids, waste waters from the process, paint residues.

2. Soft wastes:

• tars, petroleum industry mud, mud (from joint or industrial treatment)

3. Solid wastes:

• tires (full or in pieces), plastic wastes, wood wastes, substitution raw materials

Waste incineration in the cement kiln is interesting for the waste producer because it provides a guaranty of total safe disposal. It is also interesting for the cement factory because it saves fossil fuel and gives the plant a good image in point of pollution abatement. The community also profits through the savings of fuels, saving of hard currency - if the fuels are imported- and the lower pollution level.

Criteria for guarantee

The wastes are accepted and cremated based on some guarantee criteria referring to the records for their identification and following, and to the checking between the factories before the acceptance.

The Lafarge Standards for wastes cremation into a cement factory stipulates that the control on the burning process (sensors of the process, expert systems for the management, regularisations to high level), ensuring a very good training of the staff and the becoming sensitive to the labour protection.

Points of interest

1. For the wastes producer:

• the guarantee of a total elimination

• put a value on the power wastes

• cremation of the watery wastes

1. For the cement plant:

• substituting the noble calories

• civic industry, image of mark: the cement factory become from a pollutant factor a remediator

1. For the collectivity:

• thrift of power fossil resources (coal, coke from oil, gas)

• thrift of currency in the case of the imports

• the minimisation of the risks ( the soils pollution)

To the Lafarge Ciments (France) the cremation of the wastes started in 1989 - 1990, and today 10 factories from 10 eliminates at least an waste both from the burning process and at the level of row materials.

 Romania's Perspectives

 Romania has a very high waste potential:

• Liquid wastes (petroleum, chemical, motor vehicle industries)

• Soft wastes (petroleum mud, tars, treatment stations mud)

• Solid wastes (tires, wood, plastic wastes)

However, the mentality related to waste disposal is not sufficiently developed at the producers level. The legislation is in place, but enforcement is inadequate.

 Perspectives of Lafarge Romcim

Several items were investigated:

•  Tires:

  • - Testing,

  • - Problems upstream referring to collecting and to the financial approach of the producers/ collectors;

• Petroleum industry mud: the necessity to have an upstream partner to collect /pre-treat and transport wastes;

• Watery wastes with toxic elements.

Questions:

• Is there really a will to help the cement factories?

• Who is ready to pay for the elimination of these wastes?

 CONCLUSIONS

• The cement factory is the best incinerator.

• Lafarge Romcim is ready for this incineration.

• But we need the support of the administration and a reliable upstream partner.