Plant Re-engineering:

Contract Fine Chemicals

2000

Hickson & Welch; Castleford.

Site-based Senior Process Engineer for a multi-stage contract chemical process requiring modification to a selection of existing plants.

 

Summary of Process

Compound A

All in solvent based batch reaction between organic solid nitro compound and a liquid reagent.

Steam heated to drive the reaction and atmospheric distillation of the volatile reaction by-product formed. Removal of this by-product is necessary for the reaction to proceed.

Batch cooled and seeded. Batch further cooled with brine to maximise crystal yield. Crystals filtered and washed in a pan filter. Filtrate recovered and reused instead of toluene as solvent for next batch to recycle excess reagent.

Crystals kegged and taken to pan drier.

 

Compound B

General purpose plant modified to dissolve compound A in IPA at 70 deg C. This hazardous operation, including tankering of hot solution to the hydrogenation plant was dropped following a change of process chemistry from the research lab.

Modified process:

Slurry of compound A crystals in IPA introduced to Hydrogenation loop.

Hydrogenated product collected in ISO-tanker.

 

Compound C

Compound B solution drummed off from ISO-tanker and reprocessed in the same, but modified, plant used to produce compound A.

A semi-batch process between solid and liquid reagents to dampen the temperature rise due to exothermic reaction (although in practice this was not a problem and some heating was required).

The reacted batch was cooled and seeded and filtered to produce a wet product which was subsequently dried in the pan drier.

  

 

Specific Responsibilities

  • Process Engineering of stages before and after hydrogenation.

 Achievements

  • A re-engineered process that was successfully commissioned.
  • A sound introduction to fine chemicals.

 

 

 

Approximate Project Value

£ 100,000

Materials of Construction

Glass, glass lined carbon steel, incolloy.

Documents Produced

Revised Twig sheets, PFDs & mass balances.

P&IDs.

'Kiss' charts for trips and interlocks.

SIL assessments.

Conceptual Hazop Reports.

Process Hazard Analysis:

  • Process and equipment description.
  • Reactant properties and hazards.
  • Safe operating conditions (T, P, level).
  • Hazard identification (Reactions, toxicity, corrosiveness, flammability, overpressurisation.).
  • Relief assessment.

Detailed Hazop Reports.

Hazards

St3 dusts

Vapours - flammable / toxic

Solids can cause cyanosis.

Environment.

Manual drum handling.

Liaison

Commissioning Team.

Research Chemists.

Process Safety Chemist.

SHE dept.

Plant Managers.

Operations Personnel.

Other Engineers (Process, Mechanical, E&I).

Standards

API 520 Relief Systems.

NFPA 68 Explosion Relief.

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