New UK Biogas Plant to Strengthen the Market

The biogas plant at Staples Vegetables is now in operation and will help expand biogas production in the UK.

On 1 March 2011, Xergi handed over a new biogas plant to one of Britain's largest vegetable producers at Wrangle, near Boston in Lincolnshire.

The new plant is the first of five biogas plants to receive support from WRAP, the British Waste Recycling Action Programme. Colin Steel, Xergi's Country Manager UK, predicts that the opening of this plant will help expand biogas production in the UK.

"Potential investors in new biogas plants are hesitant and they are keen to ensure that these plants work as they should. There is no doubt that the opening of this plant will help speed up the establishment of new biogas plants in the UK," says Colin Steel. He notes that the new plant has attracted a great deal of interest from the British biogas industry.

He expects that the plant will also strengthen Xergi's position in the British biogas market, where there are many new projects in the pipeline. According to the British website Horticulture Week, there are plans to build more than 30 new biogas plants in the UK.

Waste is converted into energy and fertiliser
Staples Vegetables, as one of the UK's largest privately owned vegetable producers, supplies most of the main supermarkets. Every year the company produces a large quantity of vegetable waste which until recently was of no value to the company.

The biogas plant makes it possible to extract biogas from the waste and use the gas to produce energy in the form of electricity, heat and cooling. The plant will run on vegetable waste and maize silage, and the plant will process a total annual quantity of biomass of approx. 26,000 tons.

The biogas plant has capacity to produce 1.4 MW electricity and is expected to produce just over 11 million kWh electricity a year.

Staples Vegetables itself will use a large proportion of the electricity produced, but the plant will also supply green electricity to the National Grid corresponding to the annual consumption of 1,500 households. Surplus heat from electricity production will be used to heat the company's offices during the winter months, although most will be used to cool the company's warehouses. The cooling system is a heat absorption cooling system, which converts the energy in hot water into cooling.

Xergi has supplied a plant with the most advanced technology, including, for example, new technology to feed the reactor tanks with biomass, and for electronic monitoring and control of the processes inside the plant. The new technologies were a prerequisite to qualify for WRAP funding.

According to plan
Project Manager Steffen Busk Nielsen says that the Xergi project is running entirely according to plan.
The biological processes inside the biogas plant were started up in November 2010. By January, there was sufficient biogas production in the plant to start the plant's gas engine for the first time, which meant that production of electricity and heat could also begin. The absorption cooling system will be commissioned at a later date.

More here...

Biogas Plant Gasholders and Managing CDM In-house

The following article is based on an extract of Wet News (November 2008 issue)the original article is about work done by May Gurney to refurbish and improve the current Severn Trent Coalport, anaerobic digester which digests sewage sludge.

I was particularly interested in the information about the biogas gas holder, which they also call a gas-bag due to its flexible construction. We are told that, the installation of a new, larger gas bag will add to efficiency of the site.

The new spherical gas holders are the most immediate visible sign of the state of the art solutions that have been implemented at the Severn Trent sites. These are golfing ball white spheres which are created from 2 polyester and PVC-based skins, the outer being inflated by air pressure and holds up the structure. The inner skin is postponed inside he outer skin and contains the biogas.

The wonderful thing about these new biogas holders is that they are made from materials which are immune to the corrosive nature of the unscrubbed biogas, which with its hydrogen sulphide content produces feeble sulphuric acid on contact with the water in the saturated gas. This would simply severely damage an unprotected steel container.

The writer informs us that there are apparent savings from a gas holder bag compared against a traditional rigid gas holder. A traditional steel gas holder also needs a significant civil structure which is full of water and contains what amounts to a steel bell, while a gas bag simply sits on a concrete base. The bag also needs less upkeep and isn't subject to freezing in winter. This produces a far smaller carbon footprint and a reduction in capital and operational spend.

The new gas holders are also in truth crucial pieces of process plant, instead of the mere storage vessels their name advocates. They maintain a consistent system pressure needed for the proper operation of engines, boilers and waste gas flare stacks. They also have level instruments that measure the height and volume of the inner gas bag to provide signals for process control, so they have to be simple, trustworthy and tough.

In-house Design Process and Safety

We are also told that further efficiencies and economies have been driven into the Severn Trent project thanks to the proven fact that May Gurney handled the complete design process in-house, from taking the outline design produced by Severn Trent's framework designer, thru to completion. While many main contractors might outsource the design part of such projects to an external consultant, May Gurney has its own expert team, so both reducing cost - making economies of scale and avoiding passing on fee-on-fee margins to the customer - and also reducing risk thanks to better control of safety in design risk assessments. Derek Shepherd is May Gurney's design chief, who is in charge of design coordination.

He explains the benefits of the full service approach : "By taking more control for Design Management upon themselves, and not passing it to a third party, they are hey believe particularly assured of coverage in all sides of the projects.

There's less risk, Derek points out, and by not having to confirm someone else's design we also save time without doubling up effort." Better still, the in-house design team have made a contribution to better environmental performance.

Derek Shepherd believes that, by having an independent and unbiased designer, they managed to identify all products, materials and providers based on performance and an overall design approach to the system. This was instead of it being based on any existing commercial relations.

Source: Wet News

Biofuels in the European Context: Facts and Uncertainties

The report "Biofuels in the European Context: Facts and Uncertainties" has been published on the Biofuels TP Secretariat web site (http://www.biofuelstp.eu/newsletter.html ).

The European Biofuels Technology Platform (Biofuels TP) is EU funded and is to contribute to the development of sustainable, cost-competitive, world-class biofuels technologies, to the creation of a healthy biofuels industry and to accelerate the deployment of sustainable biofuels in the European Union through a process of guidance, prioritisation and promotion of research, development and demonstration.

The platform is now up and running and this is just one of 8 reports now available for downloading from their web site. This provides an interesting new resource for those of us that believe that there is a big future for biofuels from Anaerobic Digestion and wish to learn more. Most new Anaerobic Digestion plants built and planned fior the UK so far have concentrated on electricity production, and I feel that the biofuel capability of AD has hardly yet been properly explored.

After all, wind power, hydro, solar and wave power etc,. will never be able to produce transport fuels directly, and fuel production from methane avoids the power generation and transmission inefficiences inherent in electricity production.

Biofuel from food crops is becoming increasingly unpopular as it is seen as contributory to world food shortages and recent price rises.

This first report introduces its content as follows:-

"The report presents facts, findings and models regarding biofuels in a broad context. It points out the associated uncertainties. The document identifies scenarios which may evolve in either a predictable or non predictable way in the future but which in turn may considerably influence the debate. Finally, this report has identified open issues."

The report devotes only one small section to anaerobic digestion though.

"Making biogas itself saves GHG emissions because it avoids methane release from stored manure, but it is more economic to use biogas locally, to generate electricity and heat. This saves the cost of purification, distribution, compression, storage, and vehicle modifications."

I am not sure at all that "stored manure" produces biogas, perhaps an agricultural expert would email in and tell me...

However, this runs contrary to what a number of people have said to me recently.

I have been told that the additional cost of biofuel conversion equipment is beneficial for biogas plants because during the summer for example when it would be swutched on, there is no heating demand and CHP systems stand idle while biofuel conversion can be taking place on methane gas at a much higher overall efficiency, because the energy efficiency of running biogas power generation without a CHP load are acknowledged to be low.

As ever, your emailed comments are welcome, and we will publish good ones. However, for some obscure technical reason the comments sign-up page does not seem to be functioning on the blog though.

Biological Gas Desulphurization Process Wins IChemE Award

A biological gas desulphurization process developed as a result of co-operation between Shell Global Solutions International B.V. (Shell Global Solutions) and Paques has received a major accolade at the annual awards of the Institution of Chemical Engineers (IChemE) held in London.

The team was awarded the ‘Sellafield Award for Engineering Excellence’ for the development of a biological gas desulphurization process, which integrates gas purification with sulphur recovery. The award recognizes outstanding contributions to safety, the environment, sustainable development and other aspects of the chemical and bioprocess industries.

A major benefit of the biological gas desulphurization process is its simplicity. In excess of 99.8% of the hydrogen sulphide can be removed and, depending on pressure, less than 4ppm hydrogen sulphide is possible in the treated gas. In the process, virtually all the hydrogen sulphide is turned to elemental sulphur so there is no need for flaring or incineration of hydrogen sulphide containing off-gasses.

The technology used – originally developed in cooperation with Wageningen University – avoids many of the challenges associated with redox chemistry through non-fouling or hydrophilic nature of the bio-sulphur produced. This bio-sulphur can be used in the manufacturing of fertilizer.

The Shell Global Solutions Gas Treating department together with Paques B.V. developed the biological gas desulphurization process which integrates gas purification with sulphur recovery in one process unit and it is well proven having been in operation since 2002. It is designed to be easy to operate and has limited maintenance requirements with a high on-stream time. A key benefit for the operator is that direct treatment of high-pressure natural gas and syngas can lead to significant operator cost savings making it ideal for use with LNG plants and gasification units.

An additional safety feature of the process is that once the gas leaves the absorber there is no free hydrogen sulphide. More ...

Webmaster: As Paque is a biogas specialist company this process can presumably be used for scrubbing digester biogas as well as LNG, and gasification units for use of biogas in natural gas systems and vehicles. However, this would need checking with the supplier.