Industrial Total Water System (TWS) Modelling
The operational costs of all water treatment systems are not just driven by the volumes of water being treated, but more importantly by the chemistry of the water. For this reason, a water treatment audit must include both hydraulic flows, and also a chemical mass balance. This type of Total Water System (TWS) holistic audit allows us to create a virtual model of your complete industrial water system. The addition of chemistry permits us to match actual water sample chemical analyses with the model, thus validating the whole model. Once we have this, we are then able to model variations on the current system, establishing the impact of such changes as water sources, flows, consumption, chemistry and costs.
For some organisations, understanding your current water system is a sufficient goal, but for many it is looking for the optimum means, financially and technically, of reducing water consumption through reuse or recycling.
We have experience of carrying out TWS audits in industries as varied as power generation, paper manufacturing, data centres, refineries and chemical plants in regions including Europe, North and South America, India, South Africa and Eastern Asia. Most of our team have worked with Data Mobility Systems (Falmouth, Maine) in the past – which originally developed this technology. (DMS is now owned by Ecolab).
The reasons for undertaking a TWS audit are as varied as the facilities audited. In a few cases the main goal is to understand the existing water system in detail; in others it is to solve problems, but the most common reason is to reduce water consumption and discharge. In many cases this leads to a reduction in annual operational costs – often in seven figures (US$) – but against this may have to be set capital expenditure. This leads to another common reason for modelling future options – which is to assess and validate capital proposals using different technologies. An independent audit can assess alternatives, establish expected operational costs and perhaps most importantly identify unintended consequences with the proposed schemes.
To discuss a TWS Audit of your facility, please contact us…
- The first step is you will need to get in touch. We will then discuss with you your goals for the study, industry type, plant characteristics and the size of the plant.
- We will then develop a proposal and a price for the work which we will submit to you for discussion and approval.
- Once we have agreement on the scope of work and costs, we would expect you to issue an official Purchase Order and we can agree timing for the audit.
- On-site audits typically take from 2 – 10 days, depending on the size and complexity of the facility. We would normally have 1-3 people on site each day and would need extensive access to engineering drawings, designs and operational data. We recognise that this information is sensitive, and we will sign confidentiality agreements if requested. Although we will be using proprietary software for modelling the facility, all the data supplied and developed remains yours. The on-site audit also includes sampling of key water streams (up to 30 samples or more on a complex facility). These will be sent off for a detailed chemical analysis, either at a local independent laboratory or at a lab in the UK.
The current pandemic prevents us in many cases from having a team on your site. This presents its own challenges, but we believe we can get around this if your personnel are able to provide us with an accurate drawing of the existing water system in the facility (with flow volumes); details of key operational systems (we will specify the data we need and provide an Excel spreadsheet to complete this exercise); and collect and dispatch water samples (again – once we have the process flow drawing we can specify the sample locations).
- At this stage we begin developing the Base Case model of your facility on the day the water samples were taken (we recognise this is a snapshot, which means choosing the correct day to measure flows and take the samples is critical). Building the Base Case scenario is the most time consuming part of the project as we cross-check the plant design and flows with the chemistry seen in the water. We often discover leaks, overflows, unexpected chemical reactions or mistakes in the process flow diagrams at this stage. This can take some time to resolve, and involve considerable discussions. When this is complete, we should all be very confident that the model matches the operations and conditions on the plant on the days of the audit. Variations on the base case can then also be developed to cover different seasons, operational and process conditions or plant load if required.
- Once we have a validated Base Case, the fun begins. We can now build variations on the base case by changing anything we wish in the model. Typical changes include alternative water sources, changes to plant design, reusing or recycling water, etc. The only limit here is our imagination. For each scenario modelled, we can assess both the technical and the economic impact of the change.
- Finally, we write a report and present our findings to you. This can raise some new ideas, so we may need to do some extra modelling before the project is complete.
How long does it take?
The length of time this takes depends very much on the availability of the plant data and the size and complexity of the facility. Below is a diagram that shows the typical timing for a large complex facility. This shows that developing the Base Case can take 3 months and the whole project could last six months. This is not unusual and although we have completed projects in 2-3 months, some have taken up to a year (with a lot of discussion and interaction).
The diagram also shows the time required by you, our customer. This is in the outer blue ring. We try not to disrupt your normal work flow to a great extent, but inevitably there will be some demands on your and your team’s time. With the issues created by the Coronavirus pandemic, the commitment from your team will be greater in the early stages of the project.
As you can see, projects of this nature take a considerable time commitment from our team at Papertex. For this reason, we are typically only able to undertake 4-6 projects a year.