IGS, Ingenieurbüro für Energie- und Umwelttechnik

Oxytherm: In steam generation, the boiler feed water must meet certain minimum requirements in terms of quality. In the returned condensate and in the additional feed water gelös gases lead to dangerous corrosion in the steam and condensate network. There are several ways to remove the gelled gases. The method of choice is thermal degassing. This process makes use of the chemical-physical law that the solubility of gases in liquids decreases with increasing temperature and approaches zero in the boiling state. In the feedwater tank and the attached degasser dome, the feedwater is heated to boiling temperature in countercurrent by direct steam injection. The gases released escape into the atmosphere via a valve in the headspace of the degasser. This takes place due to the set pressure drop between the degasser and the environment. In the process, steam always also flows into the atmosphere via the valve as a transport medium (fine steam). The valve should be set in such a way that even under the most unfavorable conditions all the gases released are removed. According to the literature, the required volume flow is up to 0.5% of the steam output of the boiler. In practice, the flow rate is set empirically and no one knows the actual losses. Determination of the actual losses is only possible by means of complex measurement technology or by condensation of the steam. Measurements in a number of boiler houses showed losses in the range of 0.15 to 3 % of the boiler output. The steam demand of the deaerator can be significant, depending also on the time of use of the steam generator. The patented process reduces steam losses by up to 95%. The oxygen content in the condensate and make-up water and the flow rate are measured in the feed to the deaerator. A programmable logic controller (PLC) determines the actual gas volume and controls the exhaust valve. The actual opening time of the valve and thus the amount of steam loss can be reduced to a fraction. A small sample flow is diverted from the feed line to the feedwater tank via a pump, cooled via a heat exchanger (plate apparatus) and passed through the measuring cell. There, the yellow oxygen is measured. A flow meter is installed in the feed line to the deaerator, which transmits the flow rate as a signal to the PLC. In the PLC, the O2 concentration determined is offset against the flow rate and the proportion of the remaining inert gases is calculated using appropriate factors. Specific factors (depending on the water analysis carried out in advance) are also used to calculate the proportion of CO2 that is produced under thermal load in the feedwater tank and in the boiler from the carbonate during so-called soda splitting. The total gas volume determined in this way, which is introduced into the system, is continuously added up until an adjustable limit value is reached. Then, the automatically controlled pressure relief valve opens for a defined period of time to release the harmful gases that have accumulated in the headspace of the degasser into the atmosphere. The appropriate parameterization of the opening interval and duration ensures that the remaining volume of inert gases after the flushing process is so low that it does not affect the quality of the boiler feed water. The controllable exhaust valve is installed downstream of the existing one. It is a valve that is open in the de-energized state. Thus, in the event of malfunctions, the system automatically returns to its original operation. For individual determination of the steam losses of the thermal degassing, a measurement of the actual condition can be carried out on site. The achievable savings are an important basis for deciding on the economic use of the process. A steam boiler with a capacity of 10 t/h is assumed as an example of the savings potential of this system. With a steam loss of 0.5%, this results in a steam loss of 438 t over the year. Of this, up to 95 % (416 t) can be saved. At today's fuel prices, a ton of steam costs around 50 €/ton. This results in annual savings of around 20,000 €/a. Depending on the size of the plant and the equipment required, the costs for the new system are between 20,000 and 25,000 €, resulting in very short payback times. The development of a pilot plant was supported by the German Federal Environmental Foundation in the form of a grant. In June 2000, the process for reducing steam losses in the thermal degassing of feedwater was awarded the Bavarian Energy Prize for its high degree of innovation and positive impact on natural resources and emissions. More than 30 plants have since been realized. Konditherm: It is a patented process for heat recovery from steam. The fumes are precipitated by means of mixed condensation. Due to the reduction in volume during condensation, no backpressure is built up. A negative pressure can even be deliberately generated. In principle, any exhaust steam source can be used with the process. The process is designed for the utilization of flash steam. Post-evaporation occurs in all processes in which pressurized condensate is expanded to a lower pressure. Examples are blowdown or blowdown at steam boilers, but also production plants where process steam is used. The flash steam is fed to a reactor above a liquid sump. The liquid coming back from the consumers (heat transfer = condensate) is finely rained in the headspace of the reactor. The steam condenses on the droplets, causing the liquid to heat up by a certain temperature difference. The heating is essentially dependent on the available head or the residence time of the droplets in the reactor. When properly sized, the vapor introduced into the reactor is fully condensed.  

The condensation heat is completely transferred to the liquid. This is sent by means of pumps über pipelines to the consumers and gives there the absorbed heat again. The consumers can be space heating, hot water production, absorption chillers or similar. The cooled liquid is recycled back to the reactor. An overflow in the reactor allows the condensate to be recovered. The amount of condensate produced is a measure of the heat recovery. The process does not require the use of heat exchangers. It is an extension of the existing condensate system. Condensate is simultaneously used as a heat exchanger. In addition to the pilot plant realized at the Heizkraft of TUM, Garching, a large-scale technical plant in the tire industry has been in operation since 2007 and another will be commissioned in 2011.

We are your contact for internal energy supply. We reduce your operating costs through consulting, implementation of measures, concept development, planning and project management.

• Energy consulting Competent consulting in energy technology and media supply Inventory surveys and weak point analyses Concepts for the realization of savings potential Application for consulting grants
.
• PlanningProject planning Realization of optimization concepts New planning Inventory survey up to commissioning
• Comparison of breweries in terms of energy consumption (BVE) Location determination Control of energy consumption and energy costs Statistical basis for the brewing industry Evaluation of the operational situation
.
• Oxytherm Patented process for reducing steam losses in thermal feedwater degassing. In the meantime, more than 30 plants have been put into operation.
• Konditherm Patented process for heat recovery from steam burns in various processes and energy conversion.