Speciality, fine and commodity chemical production sit at opposite ends of the same industry, and the engineering problems differ accordingly. A multi-purpose batch plant running frequent campaign changeovers has a hazard profile that moves with the product. A continuous commodity plant has a fixed profile but far less tolerance for unplanned downtime. Both are governed by the same regulations and neither is well served by generic engineering.

Projex Solutions provides multi-disciplinary engineering design, process safety studies and EPCM project delivery across all three. We work on new plant, on scale-up from pilot to commercial, and on the harder job of modifying plant that has to keep producing.

What makes this work different

Campaign changeover moves the hazard. On multi-purpose batch plant, the dangerous substances present change with the campaign. That has consequences for DSEAR assessment, hazardous area classification and COMAH inventory that a single point-in-time assessment does not capture. The right question is not what is on site today but what the plant is licensed and equipped to run.

COMAH tier status drifts. A new product, a larger intermediate inventory or a substance reclassified under GB CLP can move an establishment between tiers. Where that triggers an upper tier duty it brings a safety report with it, and the engineering case has to support it.

Scale-up is where most of the risk sits. Chemistry that behaves predictably in a pilot vessel behaves differently at commercial scale. Heat transfer area per unit volume falls, mixing regimes change, and reaction exotherms that were manageable become the design case. Scale-up is a process safety exercise as much as an engineering one.

Ageing assets. Much of the UK’s fine and speciality capacity operates in plant that is decades old, where the original design intent is poorly documented and modifications have accumulated without a coherent record.

Where we help

  • HAZOP and HAZID facilitation with an independent chairman, and the multidisciplinary team where a client cannot resource one
  • LOPA and SIL determination and verification to BS EN 61511-1:2017+A1:2017
  • DSEAR assessment and hazardous area classification to BS EN IEC 60079-10-1:2021 and EI 15 (5th edition, 2024), with CompEx-certified engineers
  • Feasibility and FEED studies, with the estimate accuracy band stated up front
  • Scale-up engineering from pilot to commercial, with the thermal and mixing design treated as a safety case
  • Debottlenecking and capacity uplift on existing plant
  • Pressure systems design developed alongside the written scheme of examination required under PSSR 2000
  • 3D laser scanning so that tie-ins on congested legacy plant are designed against as-built reality
  • CDM 2015 duty holder support and EPCM delivery under ISO 9001:2015 certified project methodology

Typical reasons clients get in touch

  • A new product is entering an existing multi-purpose plant and the safety case has to be revisited
  • Scale-up from pilot needs engineering that treats the exotherm as the design case
  • A COMAH tier determination has changed or needs re-establishing
  • Area classification predates the 2021 and 2024 standard revisions
  • An ageing asset needs a considered replacement, refurbishment or end-of-life plan
  • Capacity has to increase within an existing building and an existing permit

Related

Part of our work across the chemical sector. See also formulation and blending, and polymer, resin and elastomer production.

Standards and regulations we work to

  • COMAH 2015 (SI 2015/483), with HSE guidance L111 (third edition, 2015)
  • DSEAR 2002 (SI 2002/2776), with ACOP L138 (second edition, 2013)
  • BS EN IEC 60079-10-1:2021 for gas area classification, and EI 15 (5th edition, October 2024)
  • BS EN 61511-1:2017+A1:2017 for functional safety and safety instrumented systems
  • COSHH 2002, with ACOP L5 (sixth edition, 2013)
  • PSSR 2000 (SI 2000/128), with guidance L122 (2014)
  • PUWER 1998, with ACOP L22 (fourth edition, 2014, amended 2018)
  • Environmental Permitting (England and Wales) Regulations 2016 (as amended)
  • UK REACH and GB CLP
  • CDM 2015 (SI 2015/51)
  • ISO 9001:2015, to which our project methodology is certified

Frequently asked questions

We run a multi-purpose plant. Does our DSEAR assessment need to cover every product?
It needs to cover the operating envelope rather than a single campaign. On multi-purpose plant the dangerous substances present change with the product, so an assessment tied to one recipe will not represent what the plant is equipped and licensed to run. That is one of the more common gaps we find.

Can you help with a COMAH safety report?
We provide the engineering input to safety report production and revision, including the technical case for modifications that trigger a review. We work alongside your process safety team rather than replacing them.

We are scaling up from pilot. What should we be worried about?
Heat transfer area per unit volume falls as scale increases, so an exotherm that was comfortably managed in a pilot vessel can become the governing design case. Mixing regimes also change. We would want reaction hazard data before committing to a reactor design.

Do you work on batch or continuous plant?
Both. They present different problems: batch plant is dominated by changeover, cleaning and campaign flexibility, continuous plant by availability and turnaround planning.

How do we start?
Usually with a conversation about the problem rather than a formal enquiry. If a feasibility study is the right first step we will say so, and if it is not, we will say that too.

Talk to us about your plant. Request a call