Description

Level measurement in the aniline hydrogenation reactor

Requisitos para el punto de medición

  • PTFE Lens antennas (no tank intrusion), insensitive to deposit
  • For demanding liquid applications involving narrow tanks and internal obstructions

Description

Flow measurement of derived acidic iron oxide suspension

Requisitos para el punto de medición

  • Resistant against hydrochloric acid
  • Extreme abrasion resistance

Description

Flow measurement of intermediate product MDA (methylendianiline)

Requisitos para el punto de medición

  • High accuracy measurement of viscous liquids, slurries and aggressive media
  • Options, such as heat tracing, purge port etc.

Description

Pressure measurement in the MDA reactor

Requisitos para el punto de medición

  • Extremely quick step response times <85 ms
  • Oxide ceramics are permanently resistant to corrosive and abrasive media

Description

Variable area flow measurement at the sniffing pipe in the raw MDI area

Requisitos para el punto de medición

  • Phosgene service capability optional
  • Purgemeter with 2 optional limit switches for flow monitoring

Description

Data acquisition, analysis and management of process analytics of the raw MDI

Requisitos para el punto de medición

  • Increased availability of gas chromatographs and critical process analysers
  • Automated analyser validation procedures using standard methods (ASTM 3764)

Description

Pressure measurement of phosgene synthesis

Requisitos para el punto de medición

  • Process control
  • Extra safe with optional secondary process seal

Description

Differential pressure measurement in the cooling circuit of the phosgene synthesis

Requisitos para el punto de medición

  • Monitoring of heat exchanger

Description

Hydrostatic level measurement

Requisitos para el punto de medición

  • Level control

Description

Variable area flow measurement of phosgene recirculation

Requisitos para el punto de medición

  • Phosgene service capability optional
  • Various stainless steel and alloy sensor materials

Description

Pressure measurement in the raw MDI tank

Requisitos para el punto de medición

  • High accuracy measurement of aggressive fluids
  • Remote converter option

Description

Flow measurement of raw MDI

Requisitos para el punto de medición

  • High accuracy mass flow and density measurement
  • Device commissioning, verification, diagnostics and monitoring via a secure wireless Bluetooth

Description

Flow measurement of fresh and recovered phosgene/solvent mixture

Requisitos para el punto de medición

  • Phosgene service capability optional
  • Large dynamic range, no pressure loss

Description

Differential pressure monitoring of heat exchanger for MDI distillation

Requisitos para el punto de medición

  • Precise and long term stable measurement
  • Robust measuring cell
  • Bluetooth device access

Description

Data acquisition, analysis and management of process analytics of the raw MDI

Requisitos para el punto de medición

  • Increased availability of gas chromatographs and critical process analysers
  • Automated analyser validation procedures using standard methods (ASTM 3764)

Description

Flow measurement of heat transfer circuit of MDI distillation

Requisitos para el punto de medición

  • Integrated P+T measurement: output of gross/net heat
  • Optional integrated reduction of nominal size for a large measurement span

Description

Pressure difference over distillation trays

Requisitos para el punto de medición

  • High performance DP transmitter with integrated line pressure measuremen
  • Outstanding temperature and static pressure stability even under harsh conditions

Overview

Polyurethane production in plastics & polymers production

Reliable and Durable Process and Monitoring Instrumentation for the Polyurethane Production

Polyurethane is the basis for many foam and insulating materials, for moulding materials, elastic fibres, polyurethane paints and adhesives. Polyurethane is manufactured in several intermediate stages using the intermediate products aniline, MDA (methylenedianiline) and MDI (methylene diphenyl diisocyanate). Firstly, aniline is created from nitrobenzene, water and hydrochloric acid in a continuous liquid phase hydrogenation process using an iron catalyst. In the next step, MDA develops as the aniline condenses with formaldehyde in the presence of hydrochloric acid as a catalyst. Adding caustic soda neutralises the mixture and the MDA can be separated. A raw MDI mixture develops by phosgenating MDA in a solvent. The solvent, excess phosgene and the hydrochloric acid by-product are recovered and recycled. Next, the MDI is treated by way of fractional distillation, crystallisation or sublimation so that this main pre-product can be used to manufacture polyurethanes.

The operating conditions for manufacturing MDI present huge challenges for the flow, pressure and level measuring systems in terms of reliability and durability. Besides their extremely corrosive properties, the produced substances tend to crystallise out and are partly toxic. KROHNE's portfolio includes many quality products in this respect that meet these types of process requirements. For example, ultrasonic flowmeters based on the transit time difference principle for use in the flow and return of the solvent with a high phosgene load. The device can also detect changes in the process, concentration changes or contamination in the liquid by way of sound velocity. It can also reliably monitor the cooling of the highly exothermal phosgene synthesis using our electronic differential pressure measurement systems. And use of the CalSys analysis management and data acquisition system (AMADAS) enables predictive maintenance of the process analytics, keeping faults and maintenance costs to a minimum. The increased availability improves yield and the quality of the product at the same time.

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