Alkylation units are an important part of increasing many petroleum refineries’ capacity for production. During the alkylation process, low-molecular-weight alkenes, like propane and butane, are transformed into alkylate, a high-octane component of gasoline.
After the separation of the reactor effluent into acid and hydrocarbons in the acid settling tank, the next stage of alkylation is storage and cleaning. Storage and wash vessels in the alkylation unit include those for fresh and depleted acid and water, an acid analyzer settling pot, and a number of wash tanks. Caustic washes neutralize free acid carried over from the reaction zone and neutralize alkyl sulfates in the net effluent. Water washes decompose remaining esters and remove caustic and salt that might have carried over from the caustic wash.
Magnetrol® has produced an applications brochure for the petroleum refining industry detailing level measurement challenges and solutions for each step of the refining process. This blog post is part of an occasional series exploring each application in detail.
Level Measurement Challenges and Considerations
Interface level control in caustic and water washes prevents corrosion and fouling of the deisobutanizer and other downstream units. Levels rising above high set points can cause carryover of caustic or water, while too low levels can cause hydrocarbon carryunder. Instrumentation selected to measure alkylation tanks must be able to accurately and reliably detect interface level.
Level Measurement Solutions
MAGNETROL has produced level measurement solutions for alkylation tanks:
- For point level:
Echotel® Models 910, 961 or 962 ultrasonic level switches; or Model A15 displacer-actuated switch
- For continuous level:
E3 Modulevel® displacer-actuated transmitter; Eclipse® Model 706 guided wave radar transmitter; or Pulsar® Model R86 non-contact radar transmitter
- For visual indication:
Atlas or Aurora® magnetic level indicators can be supplied with switches or transmitters
For more information on level measurement solutions for alkylation tanks and other petroleum refining applications, download the petroleum refining brochure. And for more information on interface level measurement, download the interface brochure.