- Generation of electricity from ORC waste heat increases the economic efficiency of modernized cogeneration plants.
- Highly efficient CPS micro gas turbines feature a total efficiency of up to 98%
- High temperature heat pumps and chiller units with climate friendly refrigerant CO2
- Wide range of technologies and procedures for energy-efficient exhaust air pollution
Generation of electricity from ORC waste heat opens up new methods of modernizing cogeneration plants. Organic Rankine Cycle (ORC) systems use waste heat in a temperature range from 90 °C to 600 °C with profitable success. This makes them a key technology for improving the efficiency of distributed energy supply.
For example, the efficiency of existing cogeneration plants can be greatly increased when they are modernized and operated in combination with ORC systems. As a result, the operating costs of CHPs that are operated with sewer gas are considerably reduced and the investment made yields excellent profitability.
When a CHP is modernized, the engine must usually be replaced. When the CHP is retrofitted with an ORC module, however, there are numerous benefits: The ready-for-connection ORC compact modules can be incorporated with almost no downtimes; operation of the financially depreciated CHP can be continued without having to change to it; the total electrical efficiency is increased by up to 50%; and the residual heat can still be used for heating purposes. What is more, the re-investment criterion of 50% that is required for modernization is fulfilled; as a result, the CHP bonus of 30,000 hrs can be reactivated for the existing CHP when an ORC module is installed.
Depending on the waste heat level (between 90 °C and 600 °C), Dürr ORC systems convert 10% to 18% of the thermal energy into electricity; in combination with gas turbines, it is even possible to reach 30%. For example, the residual heat can be used in heating or drying processes.
Typical waste heat sources are geothermal systems, (biomass) combustion processes, exhaust air purification plants, gas turbines, or combined heat and power units. ORC is therefore ideally suited for applications where the domestic current and heat requirements are at a constantly high level all year round, for example in sewage treatment plants. Dürr supplies ORC compact modules having an electric power of 40 to 400 kW for individual solutions.
Highly efficient CPS micro gas turbines for generating domestic current and heat: The Compact Power System (CPS) is based on micro gas turbine technology and is a highly efficient small power station for combined power and heat generation. The fuels that can be used can, for example, be natural gas, biogas and biomass as well as methane, sewer gas or dump gas, which are burned with extremely low emissions. It is also possible to generate electricity from weak gas, e.g., in biogas upgrading.
Micro gas turbines not only have a high electrical efficiency of up to 30% (net) and a total efficiency of up to 98% but also a high availability and reliability thanks to the characteristics of the system. In many cases of application, it is possible to yield a high return on the capital employed and to reduce operating costs, for example, in the generation of steam, hot and warm water generation or in drying processes. A CPS often provides more benefits than a conventional gas engine CHP.
The CPS is ideally suited for operators with continuous domestic current and heat requirements, for example, companies in the food and beverage industries as well as supply and disposal companies, sewage plants, or public utility companies.
The Dürr CPS has an electric power of 100 kWel (net) which can be adjusted between 30 and 100 kWel. The thermal power in the turbine exhaust gas varies between 210 and 520 kWth depending on the model. Exhaust gas temperatures vary between 270 °C and 650 °C depending on the exhaust gas output.
High temperature heat pumps and chiller units with climate friendly refrigerant CO2: With their flow temperatures of up to 90 °C (100 °C), the thermeco2 high temperature heat pumps from Thermea, a company owned by Dürr, open up new ways for a more efficient use of energy and resources in sludge drying and biogas plants. Modern local heat concepts make it possible to use the energy potential of sewage plants that lies waste so far. When using high temperature heat pumps, public utility companies, operators of sewage plants, disposal companies, energy providers or operators of biogas plants have an attractive instrument to increase their profitability or reduce their operating costs.
When thermeco2 high temperature heat pumps are combined with cogeneration plants that are operated on the basis of micro gas turbines, their fuel utilization degree can be increased up to 250%. The energy systems that can be implemented in this way are particularly efficient and are not only used in the fields of sludge drying, biogas plants and local heat but also in many other industrial applications.
The heat output of thermeco2 high temperature heat pumps of the HHR and HHS ranges is between 45 and 1100 kW per machine. Due to the natural refrigerant CO2, they are a future-proof alternative to HFC refrigerants which are damaging to the climate, such as R404A, R410A, R407C and R134a. Starting in 2015, the use of HFC refrigerants will be prohibited and considerably restricted by the new F-Gas Regulation.
The new ADR/ADS thermeco2 compressed-air refrigerant-type driers for large-size compressed-air systems are a special highlight. These particularly climate-friendly refrigerant-type driers can optionally be equipped with a heat recovery unit of up to 90 °C. They are the first refrigerant-type driers in the market the investment costs of which are refinanced by the heat recovery unit while operating costs are comparable.
Energy-efficient RTO exhaust gas purification with heat recovery: Regenerative thermal oxidation (RTO) is a particularly energy-efficient and flexible solution which Dürr especially provides for purifying pollutant and odorous exhaust air of sewage plants in chemical parks.
RTO oxidizers combust pollutants at temperatures of up to 1000 °C. To achieve this, however, they require an extremely low amount of additional primary energy because they regeneratively recover up to more than 95% of the energy required for preheating the exhaust gas. The system already runs "autothermally" at low pollutant concentrations (approx. 1.5 g/Nm3 and higher), i.e., the exhaust air purification plant does not require any additional fuel, such as natural gas. RTO oxidizers are highly flexible in their design and therefore meet different emission requirements. Provided appropriate methods and materials are selected or suitable procedures are combined, it is even possible to reliably purify corrosive humid exhaust gases that are laden with odors or halogenated hydrocarbons. The Dürr RTO range comprises units for exhaust air volumes from 3,000 Nm3/h up to more than 100,000 Nm3/h.
In addition to RTO oxidizers, Dürr offers a wide product and process range of powerful technologies for exhaust air purification in sewage plants as well as for industrial sewage treatment or the treatment of hazardous waste. It allows applying customized solutions which set standards with regard to emission limits, energy efficiency, reliability, and service life.
