Cost optimization in steam and cooling circuits

In processes with the use of pure water, the online monitoring of organic contaminants is of great importance because they may lead to damages of the whole plant. The guidelines for the quality of condensate, steam and boiler feed water are becoming more stringent. Now, it is standard to set an alarm at 0.1-0.2 mg/l C. By use of an online TOC analyser system the quality and the organic parts in steam and cooling cycles can be monitored. The aim of online monitoring is to detect contaminated streams fast and to redirect them minimising expensive pure and hot water losses.

Generating steam is a costly process. A medium-sized boiler consumes about 100 m³ of water per hour and produces 100 m³ of steam per hour. The costs for energy are 25-50 € per m³. Overall, about 2,500-5,000 € per hour, means € 21.9-43.8 million a year for the generating of steam are incurred.

Following relationship exist: Boiler feed water = make up water + condensate return water.

The more condensate and residual energy is reused, the less additional make up water is required that has to be treated chemically which is expensive. Chemical additives are added to protect the boiler and piping stystem and to keep the water in certain purity. In particular, corrosion should be avoided because it reduces the boiler's heat transfer and damages the boiler and piping system. Depending on the remaining energy a price of 6-10 €/m³ is assumed for condensate water. With a make up water price of 1-2 €/m³ when draining the water results in a loss of 7-12 €/m³. For a medium sized boiler, this means an annual loss of approximately € 6.1 to 10.5 million. These high costs can be significantly minimised by reusing the condensate and the residual energy.

Contaminated water and steam can be detected by TOC measurements and redirected, so that no further damages and costs will occur. Therefore, an optimal online measurement system must be determine TOC spills accurately and fast. It must have a high availability and a long lifetime cycle with low follow-up costs.

LAR 's QuickTOC_condensate is specifically designed for condensate applications. It delivers the TOC values within 1 minute. The catalyst-free ceramic oven is the centrepiece of the QuickTOC_condensate. At 1,200°C, it reliably oxidises all carbon bonds and thus enables a complete analysis of samples. The patented calibration and validation feature QuickCalibration offers the opportunity to check the analyser at any time - automaticly and/ or by remote control. Another advantage is that this unique analyser does not need any liquid standards that must be produced or purchased expensively. These innovative methods of the TOC analyser help to optimise and reduce the processes and costs in steam and cooling circuits.