Page 21 - 6_TOC in daily practice
P. 21
Sum Parameter – Total Organic Carbon
Continuous TOC determination in Petrochemistry
No. SCA-130-611
■ Environmental protection
The natural resource of petroleum is an inte-
gral part of our modern economy. It is used not Sewage and surface waters arising in a refin-
only as a source of energy, but also as raw ery contain environmentally harmful com-
material for countless products such as plas- pounds which may be dissolved and undis-
tics, textile fibers, detergents, colorants, ferti- solved. Non-dissolved components such as
lizers or pharmaceuticals. oils and solids are often eliminated prior to
cleaning by means of gravitational separation.
Usually dissolved compounds are degraded
by biological processes. However, biological
purification plants are sensitive to the nature
and amount of influent organic impurities. In
order to prevent a reduced cleaning perfor-
mance, biological collapse of the plant, or
even a pollutant input into the environment, it
is of outmost importance to continuously mon-
itor the refining effluents.
In petroleum refineries, purified and deionized
crude oil is preheated and then separated into ■ TOC-4200
its constituents in rectification columns. Frac- The high-performance TOC-4200 analyser ap-
tions created by this process are further re- plies catalytic combustion at 680 °C. The pow-
fined, or redistilled. erful oxidation allows complete and rapid de-
tection of both dissolved and undissolved
■ Requirements to modern refineries
In many cases only so-called "cracking" of compounds, and enables the direct detection
of all contained hydrocarbons. Depending on
long-chain hydrocarbons allows the market to the sample characteristics, the total inorganic
be covered by crude oil. The purity of the re- carbon (TIC) and the volatile organic carbon
sulting products, for example low-sulfur fuels, (POC) can be measured in addition to TOC
is subject to high quality requirements, which and TC. In order to measure the total bound
leads to a corresponding complexity of pro- nitrogen (TN), the TOC-4200 can be upgraded
cess technology. The generation of steam for with a specific module.
heating material flow is an important and en- The consistent usage of inert materials re-
ergy-consuming process, which in turn also duces the risk of cross-contamination through
has the largest energy saving potential. Corro- the absorption and desorption of oils and fats.
sion on equipment such as heat exchangers All fluid paths, including the sample supply
and boilers, leads to reduced energy efficiency line, are additionally purged and rinsed be-
and contamination of the backflow conden- tween each measurement.
sate, so that it must be replaced and cleaned.
This results in high costs for the plant operator.
