Incineration with energy recovery and material recovery

Normal solid-waste incinerators with energy recovery can only tolerate up to 1% chlorine. However, such processes are not accepted as recycling by waste regulation. If HCl and/or its neutralised salts are recovered and used, then partial recycling may be claimed.

HCI recovery

MVR: MVR (Müllverwertungsanlage Rugenberger Damm) is an advanced 320,000 tonnes per year energy-recovery plant owned by the City of Hamburg. It is designed to handle much higher hydrochloric-acid levels in its raw gas than most conventional plants which provides more flexibility in waste treatment. The hydrochloric acid is recovered as a 30% aqueous solution, the purity of which makes it suitable for the chemical sector.

Trials with the addition of PVC waste (500 tonnes over five weeks) were extremely successful. No modifications were observed in the composition of the slag or the fly ash, and steam generation was not affected. Hydrochloric acid production increased in proportion to the added PVC waste and the level of dioxins in the gaseous effluent remained extremely low – well below mandatory limits.

Salt recovery

HALOSEP®: This process recovers chlorine in the form of salts from incineration waste residues such as flue gas treatment waste (FGW) and HCl scrubber liquid (HCSL). The primary advantage of this process, besides chlorine recovery, is the reduction in the amount of FGW that must be disposed of in landfills. The main product is calcium chloride brine. Successful pilot trials have been carried out and the process will be further developed in order to licence the technology or build recovery plants.

The SOLVAir® Solution: Chlorine present in fuel sources used in waste-to-energy plants, municipal and medical waste incinerators, cement kiln operations, brick and structural clay manufacture can be converted to HCl during combustion. The acid gases are neutralised by sodium bicarbonate. The obtained Sodium Chloride is recovered by filtration, dissolved in water, purified and recycled into the production of sodium carbonate. As the process is totally dry, no aqueous effluent is generated which would otherwise have to be treated. This results in a very substantial reduction of neutralisation residues.