Текст 17. Bio-energy boilers

Renewable energy production is becoming a worldwide priority as countries strive for sustainable growth and better living conditions. Many countries (e.g. EU) have already set demanding targets to increase electricity production using bio- energy resources and have introduced attractive incentives to accelerate this pro- cess. Bio-energy solutions are based on a local fuel supply and thus provide price stability, a secure supply of heat and power, and also local employment. Biofuels are increasingly becoming locally traded commodities, which will further secure

fuel price stability and availability. At the same time, green certificates and emis- sion trading offer new opportunities for financing bio-energy projects.

Boilers combusting biofuels can be used to produce only electricity, but they are mostly used in combined heat and power (CHP) plants and district heating plants. These boilers are designed to operate on a wide variety of biofuels, includ- ing extremely wet fuels such as wood residues, wood chips, bark and sawdust. Smaller boilers use grate firing technology for biofuel combustion, while larger plants use fluidized bed combustion technology. Smaller grate fired plants for thermal heat production, (< 10 MWth), have fire tube boilers, while larger ones are fitted with integrated water/fire tube boilers.

One of the world’s largest solid biofuel-fired circulating fluidized bed (CFB) boiler (550 MWth) has been built at Alholmens Kraft power plant at Pietarsaari, Finland. The CFB boiler with auxiliary equipment and the building was delivered by Kvaerner Pulping Oy and commissioned in autumn 2001.

Текст 18. Packaged boilers

Packaged boilers are small self-contained boiler units. Packaged boilers are used as hot water boilers, aiding utility boilers and process steam producers. Pack- aged boilers can be both water tube and fire tube boilers. Packaged boilers can only be used with oil and gas as fuel without separate preparation devices. A packaged boiler can also be rented if there is a need for a temporary boiler solution.

The benefits of packaged boilers over common utility boilers are:

- Short installation time and low installation costs

- Small space usage

- Lower acquisition cost

- Better quality surveillance in work

- Standardized units

The drawbacks of packaged boilers are:

- Higher power consumption

- Cleaning periods more frequent

IV. ТЕКСТЫ ДЛЯ ЧТЕНИЯ И УСТНОГО ПЕРЕВОДА