Decoking & Descaling

Decoking & Descaling

Alan Shinton | Crest Environmental Services

Alan Shinton is the Managing Director of Crest Environmental Services Limited and Crest Industrial Services Limited, he is the co-founder of both companies and brings over thirty years of practical, technical and commercial experience from within the petrochemical and industrial services industry to the business.

Responsible for facilitating all of the company activities including: Operations, alliances and channels of project support. He is also responsible for Crest's global business, creating opportunities for specific markets and industries such as chemical and petrochemical services, and utilities.

In 2006 Alan was recognised by Saudi Aramco (KSA) for delivering a highly problematic $30m project across four of their Saudi Arabia refineries safely on time and within budget. He was again recognised in 2007 and 2009 by Chevron (USA) for delivery a similar scenario in both the UK and the USA refineries.

"It is our professional attention to detail and procedures which has made us the first choice team for a number of petroleum and chemical sites". Alan Shinton

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CREST ENVIRONMENTAL SERVICES is a specialist environmental service provider, offering bespoke solutions,to the Petro-chemical, manufacturing and pharmaceutical industries.

We value our employees as our greatest asset. Crest ensures that all its employees, at every level, are trained in all aspects of their trade ensuring a safe, efficient and expert service. Training requirements are assessed on an on-going basis and delivered by external providers or by Crest Senior Management. All operatives receive daily toolbox talks from Site Management to supplement formal Health & Safety Training, in line with current issues and developments for each site.

Crest Environmental Services Limited began operating from modest premises in Cardiff, servicing local chemical manufacturers and petro-chemical suppliers and very quickly established a market niche for themselves based on attention to detail, quality of service and an innovative approach to problem solving.

During this time, Crest Environmental Services Limited have established themselves at the very front of the service, environmental and decommissioning industry. A very impressive array of major blue chip companies, like BNFL, BP, Texaco and Shell, have seen Crest’s innovative approach to problem solving as a major asset, complementing their own decommissioning activities.

Crest Environmental Services specialise in the safe handling of TEL (Tetraethyl lead) and many other substances associated with the Petro-chemical industry and their specialised knowledge has been called upon around the world. From the UK to Panama and from the Middle East to Australia, Crest will provide the solution, tailor-made to your exacting requirements.

In 2016, Crest was awarded ISO 9001 registration and our commitment to ISO 9001 is a clear statement to the regard in which quality is held by Crest. Crest is also a member of ROSPA and The British Safety Council.

Crest Environmental Services Accreditations


Deposits within process tubes and piping systems can lead to accelerated corrosion compromise flow and production rates. Overheating can be a casualty which can lead not only to compromising the integrity but can have a catastrophic effect of total failure of systems.

The extent and nature of fouling depends not only on the product but also process conditions and system design. Within crude oil systems it can manifest as petroleum coke (potentially including inorganic material) and as scale within steam generation systems and techniques have existed to remove such contamination. Mechanical cleaning, also known widely as pig decoking or pigging, has become the preferred method throughout the oil and gas industry.

Techniques such as steam air decoking and hydroblasting have varying degree sof success, depending on the competence of the personnel operating the system. There can be disadvantages to the systems that could potentially lead to increased environmental load and asset damage.

Decoking & Descaling Services


With over 20 years of experience, working on many continents, Crest Environmental Services have formulated a solution to successfully clean systems throughout the oil and gas industry.

Our industry driven solution involves connecting our Mobile Pumping Unit to the piping system and progressively scraping away layers of coke/scale with bespoke sized mechanical pigs.

Scraper pigs are propelled by pressurised water flow supplied by our Pumping Unit. This operation requires the use of water to carry all the debris back to the machine for subsequent filtration and disposal.


The mechanical scraper pigs are built in house to a patented design. There are some 50 different incremental pig sizes, ranging from 1”-12” diameter. We can discuss developing bespoke solutions for individual needs or projects.


  • All our pigs have stud pattern options which are designed subject to task.
  • Designed to ensure 360° circumferential coverage of bends and pipework.
  • Able to manoeuvre short radius return bends, plug headers, mule ears & flat-back bends.
  • Bi-directional operation and control.
  • Low pressure operation (typical operational pressure of 250psi).
  • Continuous monitoring of pressure, flow and pig positioning.
  • Residual water can be removed from process pipework following operations if required.
Decoking & Descaling Services


Commonly referred to as a DPU – a purpose built trailer, or containerised unit, which contains all the equipment and functionality to connect and deploy mechanical ‘scraper’ pigs. The unit has four basic elements:

  • Manned control room
  • Water handling tanks
  • Double pumping engines
  • All connection equipment and tooling

All our pumping units are designed, built and maintained in house. On board two stage filtration can separate particles down to 750μm. Our on board system is used to monitor the cleaning performance using various process signatures.


Removal of coke contamination from fired heater process tube assets includes:

  • Delayed Coker, Crude Distillation, Visbreaker, Vacuum Distillation along with a wide variety of charge heaters and process boilers.
  • Removal of coke contamination from transfer lines.
  • Removal of internal scale from HRSG / OTSG boilers and solar steam generation systems.
  • Descaling, dewatering, slug removal and purging of pipework and pipelines.
Decoking & Descaling Services

Benefits of using Crest Pigging Technology

  • Versatility: Available in a range of sizes, shapes and diameters, small and large (16mm to 914mm), the pigg’s body is designed to incorporate a range of different cleaning appendages that stem outwards and complete the scraping process, thereby removing scale and coke deposits. Depending on the item to be cleaned and the stage of the cleaning process, the Pigg can be customized to offer a complete cleaning process using interchangeable appendages.
  • Complete & Thorough Cleaning: Unlike some other technologies, the Crest pigging technology ensures that the pigg offers 100% descaling and decoking service by incorporating a 360° cleaning action, ensuring that even the hardest of deposits are removed without damaging the walls and surfaces.
  • Safe, Efficient & Environment friendly: Crest Pigging Technology - does not use any chemicals making it safe. There is hardly any fuel usage compared to traditional methods of cleaning. Cleaning at u-bends and complicated positions is easy and tailored to satisfaction. What’s more, since it operates on low pressure and temperature, there are no risks or tensions.
  • Smart Build: Crest Pigging Technology removes any chances of the pigg getting blocked on the already scraped deposits at any point of the cleaning process. This is because the technology incorporates a procedure through which liquid bypass surrounds the body of the Pigg, flushing out the scraped residue.
Decoking & Descaling Services
TUBE EROSION No - Stud Selection Eliminates Risk Yes - Hard Coke During Spall Phase Yes - Hard Coke And Shot Causing Erosion Yes - Potential Corrosion
OVERHEATING AND/OR WATER DAMAGE No Yes - High Risk Yes Yes - High Risk Of Fires
TUBE BLOCKAGE No - Precise Control of Coke Removal Yes - Moderate Risk During Spall Yes = High Risk With Sticky Deposits Or Wet Coil No
EFFICIENT ENVIRONMENTAL IMPACT No - All Solids Contained For Disposal Yes - High Quantities Of Solids In Hot Water And Steam Yes - High Quantities Of Solids In The Gas Yes - Large Quantities And Neutralisation Required
OVERALL EFFECTIVENESS 100% Guaranteed Cleaning 75% Cannot Clean Convection Section Or Remove Inorganics, Need Reverse Flow Facilities 50% Cannot Remove Hard Coke 50% Deposit Dependant
Achilles Accreditation | Crest Environmental Services


Crest recognise that the success of the Company is dependent upon creating a competent workforce with the necessary skills, training and experience to meet customer requirements. Accordingly, we value Company employees asour greatest asset, and are committed to Investors In People.

Training: Crest ensures that all its Employees, at every level, are trained in all aspects of their trade ensuring a safe, efficient and expert service. Training requirements are assessed on an on-going basis and delivered by external providers or by Crest Senior Management. All operatives receive daily toolbox talks from Site Management to supplement formal Health & Safety Training, in line with current issues and developments for each site. Detailed records of each employee are maintained to ensure full traceability. Crest operates a comprehensive safety management system comprising of the following:

Health & Safety Policy; Core Risk Assessments, Core Manual Handling Assessments, Supervisors Health & Safety, Health & Safety Work Instruction Manual, Employee Health & Safety Handbook.

These are supplemented by project specific procedures, method statements, risk and COSHH assessments which are in turn incorporated into the health & safety plan. Additional documents which Crest can provide are:

  • Vibration Assessments/Predictions, Environmental Plan/Assessment
  • Crest Permit to Work System, Safety Action Plan

Client supplied information which is often incorporated in the above documents:

  • Pre-Tender Health & Safety Plan
  • Materials Safety Data-sheets
  • Analytical/Investigation Reports
  • Induction Training Information


"Environmental Protection is regarded as an integral part of all areas, by every member of staff."

Crest is committed to achieving, sustaining and demonstrating world class environmental performance in all aspects of their business. We believe that compliance with current environmental legislation will cultivate environmental awareness and growth of concern with regard to the environmental performance in line with ISO 14000.

Crest ensures that the waste it controls is handled, transported and disposed of in accordance with legislative requirements. Furthermore, Crest ensures all waste streams are sorted to maximise the recovery and recycling of materials to minimise landfill and therefore cost to clients.


Decoking & Descaling Services

Crest have been entrusted by some of the world's biggest companies to deliver decoking services. Crest have delivered decoking & descaling services in North America, South America, Europe, Asia, Australia & Middle East.


Crest have over 20 years' experience of completing decoking and descaling projects. A small example of the projects completed are below:

  • EVC ( UK ) Ltd, Runcorn, UK. Mechanical decoke of 3, 2 pass EDC Cracker Heaters and transfer lines.
  • Koppers Denmark A/S, Nyborg, Denmark. Mechanical decoke of 2 pass Coal Tar Heater.
  • Caxios Ltd c/o Huntsman Petrochemicals, Wilton, UK. Mechanical decoke of 8 pass Petane Still Reboiler.
  • ELF Oil UK Ltd, Pembrookshire, UK. Mechanical decoke of 8 pass Vacuum Heater,8 pass Crude Heater, 2 pass Crude Heater.
  • BP Fortes Pipeline System, Dalmeny, Scotland, UK. Mechanical decoke of 4 pass Stripper Reboiler Heater & auxiliary pipework.
  • Esso Fawley UK: Decoke of 2 x 4 pass Crude Heaters.
  • Corus Group Scunthorpe: Decoke of 8km Effluent Process Line.
  • Repsol Refining, Puertollano Spain: Decoke of 1 x 4 pass Vacuum Heaters & 1 x 8 pass Naphtha Heaters.
  • BP, Azerbaijan: Decoke of 4km Process Pipeline.
  • ENI Tarranto Italy: Decoke of 2 x 2 Thermal Crackers.
  • Cyprus Petroleum Refinery, Larnaca, Cyprus. Mechanical decoke of 4 pass Crude Heater.
"Crest offered a totally professional service. Field based activities were backed up by comprehensive Procedures and Risk Assessments. Medical screening of Crest and our employees on a weekly basis ensured staff welfare. Start of Day Safety Talks were of an exemplary standard, focusing on the progress/successes of the previous day whilst emphasising the hazards and challenges of the day ahead. Crest actively engaged in the on site Service Employee schemes based around Contractor/Employee Safety. It has been a pleasure to work with such a professional company." Oil Refinery - Site Manager

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BP Testimonial

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“We would like to commend Crest Environmental Services, for their work during the recent demolition and decontamination of Kwinana’s bulk MFAKMstorage & blending facility.” - Kathleen Lucas, Business Unit Leader - BP Refinery (Kwinana)

Shell Testimonial

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“The operation was carried out with the utmost professionalism, with no accidents or incidents, and within the agreed time. A hazardous job well done.” Gary Smith Refinery Manager-Shell Refining (Australia)

Contact Crest Environmental Services

Innospec Manufacturing Park, Oil Sites Road, Ellesmere Port, Cheshire, CH65 4EY
+44 (0) 151 355 2786 Fax:+44 (0) 151 355 4192

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