METHANOL INJECTION MODIFICATION CONCEPTUAL DESIGN STUDY
- Client: Wingas
- Location: Lincolnshire, UK
BACKGROUND
Wingas Storage UK Ltd. (WSUK) own and operate the Saltfleetby Natural Gas facility near Louth in Lincolnshire. The gas from Saltfleetby is fed via pipeline to the nearby Theddlethorpe Gas Terminal, operated by ConocoPhillips, where the gas is combined with gas from offshore gas fields, processed and fed into the National Transmission System.
The properties of the gas are such that the potential for hydrates to form in the transfer pipeline exists. Therefore, methanol is injected at Saltfleetby in order to prevent hydrate formation. The existing methanol storage is oversized for future Gas production, and also insufficiently separated from high pressure process equipment, in line with industry good practice and guidance.
The aim of the study was to present the optimum solution for taking forward into a Detailed Design phase. The selection of this option was based upon compliance with legislation, good engineering practice, cost and schedule.
PROJECT OVERVIEW
The purpose of this Conceptual Design Study was to investigate all potential solutions for the required modifications to the Methanol Storage and Injection system at WSUK’s Saltfleetby B-Site.
In order to set a basis for the development of design options, process modelling work was carried-out. This involved identifying gas conditions arriving at Theddlethorpe, specifically the aqueous phase flow, to allow the accurate determination of methanol injection rates at Saltfleetby, and therefore the size of methanol storage vessel required.
KEY ASPECTS OF DELIVERY
In carrying-out this study, the following tasks were completed:
- Problem definition and Option Identification through conducting a ‘Clever Thinking’ exercise
- Option Selection with WSUK to review the ‘Clever Thinking’ output and to choose three potential solutions for further development
- Option Development to apply further design detail
- HAZID study conducted to highlight areas for further consideration.
- Cost Estimating and Schedule Development
For each option, process assessment, mechanical engineering considerations, control instrumentation & electrical and civil & structural assessment were considered for any further design detail.
A Hazard Identification (HAZID) Study was conducted for the proposed modifications. To enable a full comparison of the developed options, a cost estimate was prepared. A Project Schedule was prepared for the Detailed Design, Procurement, Construction and Commissioning of the identified options.
CLEVER THINKING
As part of the development of the Conceptual Design study, OSL were required by WSUK to investigate other potential options.
In completing this study, OSL utilised a ‘Clever Thinking’ processes to highlight all possible solutions for tackling the issue of hydrate formation, along with the requirement to resolve the issues around the existing methanol storage facility. These included innovative solutions alongside conventional ideas.
These possible solutions were considered alongside options proposed by WSUK. Following the Clever Thinking exercise, the options were screened with WSUK and the most attractive taken forward for further development.
It was recommended to install a replacement smaller volume, double-walled Methanol Vessel in a new location.
BENEFITS TO CLIENT
The benefit to the client was a properly considered set of design solutions to meet the operation requirements and legislation. It resulted in the most cost effective and technically compliant option being selected for development.
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