Moisture Measurement for FGD-Gypsum in EON power plant

24.04.2017 | by Michael Stoll

The EON Powerplant in Rotterdam is the biggest coal fired powerplant in Europe. The plant is able to fire 30% Biomass and a environmental friendly exhaust-desulphurisation unit is also installed. Thats where the ACO moisture sensors are operating and contributing an environmental friendly contribution.

Moisture Measurement for FGD-Gypsum in EON power plant

E.ON „MPP3“ power plant in Rotterdam-Maasvlakte

The “MPP3” is the most modern and biggest hard coal fired power plant with the notable gross power rating of net 1070 MW and a net efficiency of over 46%. The “MPP3” wants to reduce the effects on the environment as much as possible. One point to reach an environmental friendly process is the optimisation of the exhaust-desulphurisation unit. The desulphurisation is made by a wet flue gas cleaning unit controlled by a moisture measurement. This flue gas desulphurisation (FGD) is far more effective than in other traditional coal fired power plants. Beyond the “MPP3” can reach a biomass-combustion up to 30%. Of course the district heating is used from the adjacent companies.

FGD-gypsum production with an integrated moisture measurement

The desulphurisation is based on burnt lime (CaO) thereby the end product gypsum (calciumsulfad-dihydrat) arises. For the analysis of the produced gypsum there is an in-house laboratory located in Maasvlakte (Rotterdam). This in-house laboratory evaluates all the recurrent samples that have to be taken to supervise the moisture content of the gypsum. The REA-gypsum can only be traded and further processed with a moisture value around 10%. Based on this fact a continuous measuring and storage of the actual moisture value is indispensable. To avoid caking in the whole process and to guarantee the best flow characteristics in all following transport systems, a moisture measurement system is also advisable.


More possibilities for application of FGD-Gypsum and gypsum fiberboards

How does a moisture measuring sensor for gypsum work?

In the “MPP3” the moisture values are gained from an online–measuring system at the vacuum band filter. The two sensors are mounted in the individual developed over belt construction from ACO. This solution is very important to reach a successful and repeatable result of the moisture measurement. The digital moisture measurement signal is available without any delay.

Moisture Measurement for FGD-Gypsum in EON power plant

Installation of an Online Moisture Measurement in FGD-Gypsum Applications

One very important thing of moisture measurement systems is the mounting condition of the sensor. A constant material height and density should be given. To guarantee such optimal process conditions a special scraper is installed in front of the sensor. Furthermore the sensor is mounted on a sledge. This also improves the surface of the material and reduces material caking in front of the sensor. By hand-wheel the material height and the sensor position is adjustable very fast and easily.

Earlier experiences have shown that just one sensor, on a 2.4 meter wide belt, is not sufficient for an accurate moisture measurement. Due to this the moisture measurement consist out of two sensors. On one hand the repetability is higher and on the other hand the function of the sealing lip can be monitored (safety function). If there is a damaged sealing lip, the vacuum and consequently the drying process will not work as good as before. On one sensor the moisture value will increase highly. In this case the sealing lip should be replaced.

FGD Gypsum Application: Moisture Sensor mounted on a sledge over a vakkum belt dryer at EON Power Plant in Rotterdam
FGD Gypsum Application: Moisture Sensor mounted on a sledge over a vakkum belt dryer at EON Power Plant in Rotterdam

Moisture sensors for gypsum, FGD-Gypsum and gypsum fiber boards:

Moisture measurement for detecting the water content of bulk solids. The DMMS system is measuring the moisture via the capacitive measuring principle.

DMMS
Digital Moisture Measuring System

Moisture measurement for detecting the water content of bulk solids. The moisture sensors are working with the capacitive measuring principle. Measurable materials are: pellets, biomass, woodchips, sawdust, gypsum, grain, cocoa, coffee, concrete, sand ...

AMMS
Compact Moisture Measuring Sensor

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