Atom Indonesia Vol. 38 No. 3 (2012) 138-146
On-line Diagnosing on Trayed Column of Etylene
Plant Using Gamma Ray Scanning
S. Sugiharto
Center for Application of Isotopes and Radiation Technology, National Nuclear
Energy Agency, Jl. Lebak Bulus Raya No 49, Jakarta 12440, Indonesia
Abstract
Nuclear based technology called gamma scanning
technique found its application for troubleshooting and diagnosing industrial
process performance. The success of application of the gamma scanning technique
is attributed to its unique ability in providing information which is cannot be
obtained by any other techniques. One of the most prominent advantages of the
gamma scanning technique was demonstrated by implementing this technology for
scanning caustic/water wash tower DA 202 which was running in normal condition
of operation. The DA 202 tower is trayed column having diameter of 4.2 m and
height of 40 m. The scanning work has been performed using 70 mCi 60Co isotope
as gamma emitter and scintillation detector as radiation counter to investigate
condition of ten trays, starting from tray # 13 at elevation of 35050 mm to
tray # 4 at elevation of 26950 mm above ground level. Scan data show that all
trays were in their position. Tray # 4 to tray #10 were functioned properly and
carried approximately the same amount of liquid. Light flooding on tray # 11 and
heavy flooding on tray # 12 were identified. Partial flooding was identified on
tray # 13. Further examination at the time of shutdown it was found that the
liquid flooding on tray # 12 was caused by presence of a bucket covered with
solidified mud.
INTRODUCTION∗
Ethylene is produced in petrochemical industry by steam cracking in quench
tower. In this process, gaseous or light liquid hydrocarbons are heated to
750-950oC, inducing numerous free radical reaction followed by immediate quench
to stop these reactions. This process converts large hydrocarbon chains into
smaller ones and introduces unsaturation condition. Ethylene is then separated
from the resulting complex mixture by repeating compression and distillation.
Caustic/water wash tower DA 202, is one of critical components in continuous
ethylene production plants of large petrochemical industry located in Banten
province. The column is designed to quench the radical reaction in ethylene
line production. Problem identified was pressure increasing of the column.
Problem in this column leads to serious consequences to the plant operation and
hence the quality of the product. It is urgently to find out the proper method
in order to know what is really happening inside the column. The gamma ray
scanning technique as troubleshooting tool was selected to examine the cause of
the problem in this column.
The gamma scanning technique is very suitable to be implemented for
troubleshooting and diagnosing of technically complex, continuously operating
industrial plants. The advantage of the gamma scanning technique is that this
technique is applied just at the time when the plant is in operation.
Petrochemical and chemical process industries are the main users and
beneficiaries of the column scanning technology
In engineering applications, gamma scanning technique has been used for
inspection of various processing units of industrial plants and has been
reviewed [3,4] and documented. Gamma scanning technique with one source-one
detector was used to for multiphase flow regime of hydrocarbon in the
horizontal pipeline transport , distillation columns [7,8], and debutanizer of
Fluidized Catalytic Cracking Unit (FCCU) in petroleum plant. The gamma scanning
technique was also used for characterization of radioactive waste in the
container [10,11]. In combination with tomographic system, gamma scanning was
used to assay radioactive waste.
In this paper on-line measurement of radiation intensity using gamma scanning
technique is demonstrated to figure out the source of the problem in trayed
column of quench tower DA 202.
Free Full Text Source: http://aij.batan.go.id/index.php/aij/article/viewFile/179/131
No comments:
Post a Comment