MPB 2. The design of an industrial product.

Introduction to an industrial design.

In the presentation to the Mini Biogas Plant (MBP) project, which was made in a previous post in this blog, the motivation for the development of a biogas plant for decentralised organic waste management and the project that has been set up around it was already discussed.

This entry is about the study of the market, the current alternatives in the product conception and design objectives.

MPB design is basically the design of a new product. Nowadays, industrial biogas plant projects needs an individual and detailed design, where each project requires a great deal of engineering effort. In contrast, the MPB can be conceived as a product, as it can be reproduced following the same design, and can aspire to a wide market with slight modifications.

Designing a Mini Biogas Plant (MBP) involves many initial doubts, the first one is the product definition. Defining the product by the design team can only be done after evaluating different business models and after a study of the current market situation and existing products.

It is considered that the Mini Biogas Plant (MBP) should be an industrial plant scaled to process waste quantities in the range of 1 to 3 tonnes per day. Small waste producers whose waste management is costly, responsible for organic waste management in developed or developing countries, or expensive energy consumers can obtain an economic and environmental profitability from such a plant. Of course, the facilities must process this amount of input material in a stable manner and with a high degree of automation. All installations designed for an order of magnitude lower than 1 t/d are not considered Mini Biogas Plants, are Micro Biogas Plants, and would be in a different concept, the domestic biogas production.

Current market situation. Analysis of similar products.

After the development of the business models that limited the solution to the possible investment level, a comparative market study was carried out of the low-power plants or MiniBiogas Plants currently existing on the European market. This study did not take into account those installations that are not comparable, such as domestic installations for gas production or plants from research projects of companies and universities, which are not ready to be introduced on the market.

The first impression of this market is that it has yet to take off. Decentralised biogas production seems to be underdeveloped in Europe despite the fact that there are several companies trying this business model in several major European countries. Some of these models are adaptations of small-scale industrial designs, while others have risky designs.

It is notable that most of the companies offering these small-scale facilities do NOT offer industrial biogas plants. It is possible that design or operational deficiencies, a low stable production of these facilities or their investment cost are factors that make it difficult to bring this activity closer to its maximum development.

The majority of available plants focus on designs for farms, large canteen waste or supermarket rejects, as well as the use of biogas for electricity production, although in recent weeks news has come out regarding projects similar to the biogas plant concept that AGF PROCESOS BIOGAS SL intends to develop, and which it explained previously in the MPB1 entry. In those cases where an enrichment plant is associated with the biogas facility, it is again a small scale adaptation of an industrial process, which is costly. Membrane separation or absorption systems available on a small scale needs to operate under pressure or at high temperatures, which increases the investment cost considerably.

A substrate that these plants do not seems to be targeting is the small producer of industrial organic waste or the organic fraction of household waste. In other posts in this blog, estimates were made of the energy potential of the organic fraction of household waste, the majority of it is still going to landfill, which is a terrible environmental management and a waste of resources.

Most solutions are fully or partially developed in sea containers (sea containers, ISO containers), avoiding on-site construction and delivering the most complex part of the plant in terms of equipment and workshop-tested facilities. In some cases the construction of a reactor is needed to produce biogas at the final location or it is incorporated in the containers. This container solution seems to be the optimal one and AGF PROCESOS BIOGAS SL uses it frequently in industrial installations.

One element to note is that all current plants need to store the gas generated, so they have some kind of gasometer, either with flexible material (domes or bag), by water bell or even by using a maritime container for liquids for this function.

All designs are configured in several containers, usually separate, containing different elements or equipment, which requires the connection by external piping of the different internal elements of the containers. This requires a field installation with external elements: piping, valves and instrumentation, among others. These elements make the design of the entire installation and require work to be carried out on the final location of the element. This is aggravated in those designs where the containers are physically separated from each other, as is the case with the containers where the biogas is consumed.

But it is quite certain that the major limiting factor for these plants is the reaction volume. Most of the current low power plants do not have a large reaction volume, as they are limited to the volume available in sea containers; and those that have a large volume require some kind of construction at the final plant site. With the exception of latter cases, not much more than about 20 m3 of useful volume is available, so that no more than 10-20 Nm3 of biogas per day can be generated on a stable basis. Pushing the plant process too hard can lead to operational problems, such as foaming, low production, microbiological failure or a dirty, low-rich gas.

Industrial biogas plants operate in an average relative production range of 0.5 – 1 Nm3 biogas per m3 of reactor per day (Nm3b-m-3R-d-1). These industrial plants are equipped with agitation and heating systems, and it would be reasonable to assume that they operate and perform better than plants designed with the same parameters but without, for example, equivalent agitation.

It is therefore very difficult for these plants to maintain a stable high biogas production and a high input flow. Feeding one tonne of organic matter per day is likely to lead to process failure and plant collapse, even if it is possible to operate at higher relative outputs (1.5 – 2).

Considering an average production at that tonne fed, the biogas production should exceed 50 Nm3 per day, so it is difficult for these plants to achieve a stable production, as they do not have the volume to do using traditional technology. All these installations need external carbon filters or even incorporate solids separators to remove the non-biodegradable biomass for composting. A large part of these solids must still belong to biodegradable fractions that the plant has not been able to convert to gas, so that the maximum amount of energy has not been generated, which will possibly make it difficult to convert the gas into income or economic savings that will make the plant profitable.

Once the market situation has been revewed, the specific objectives of the AGF MPB design can be defined.

Design objectives.

After evaluating what is available on the market and studying different business cases, the following desings objectives are fixed. This objectives are looking for develop a plant model that supply all the deficiencies that actual plants previously envisaged.

1. Apply a highly efficient industrial process to a small-scale plant. Achieve relative biogas productions above 5 Nm3bm-3R-d-1.

The plant is designed to be able to develop highly efficient and more complex processes that allow the production of gas per unit volume to be similar to that achieved on an industrial scale by AGF PROCESOS BIOGAS SL. This allows the amount of material processed in the plant and the gas generated to be much higher than its equivalents with the same reaction volume.

This aspect is fundamental in order to make the plant profitable. To this end, it will be essential to control the operation of the plant, treating it as if it were an industrial plant.

2. Production stability.

To realice a strong and robust engineering design, which generates a stable biogas production. At the operational level this should translate into a plant with automated operation except for feedstock feeding and general maintenance.

The plant must produce biogas in a stable and controlled manner despite various feed changes. It is quite possible that logistically exists plants where feeding is not possible on a daily basis, but only once every few days or even once a week. This should not be a problem for the biogas plant, which must keep control of the gas production at all times and the stability of the different reactions.

This can be a major limitation in locating potential projects. Depending on a continuous feed for stable gas production significantly reduces the chances of operationally fitting the project in many locations.

As can be understood, this is another fundamental aspect in order to make the plant profitable, so that there are no production problems due to changes in the composition of the input materials or a specific increase in the organic charge, and biogas is generated that can be economically valued.

3. Have a contained investment cost.

Reaching this point is closely related to the optimal engineering design of the facility. The possible business models are very limited in terms of profitability and it will only be possible to expand this activity if there is an investment cost that justifies the risk and allows the investment to be profitable in those cases where the existence of waste and a justified use of the biogas generated are met.

The investment cost should be evaluated according on the basis of the intended use of the gas generated, as each use requires a different investment.

4. Optimal Engineering.

The engineering design should be as good as possible, taking care of every detail, even the invisible ones. Years of research and development have gone into the design of some parts of the MPB plant.

The design is based on the following aspects:

• Minimalist, friendly and affable design. The aim for the plant is to be as visually simple as possible, without any pipes or other external elements. It should be accesible, not excessively complicated. Normally biogas plants are not something everyday or pleasant, in many cases quite the opposite, by design and due to inadequate activity or operation. The social awareness of biogas needs to be expanded and this can only be done if it is associated with installations that are far from problems, cost-effective and not as shocking as the traditional circular concrete reactors with flexible domes.

• Take care to detail, especially those that may be critical. All the parts and pieces of the design have been evaluated in detail, especially those that are hidden but could cause a future failure of the plant due to chemical reactivity. Everything has been worked with the highest quality materials possible, using stainless steel pipes externally or internally. There are no plastic or iron pipes. As a detail, it is also considered that the plant can be collected completely inside the container, without having to install or add external elements in the final location. In this way, after feeding, it can be completely closed after collecting all external elements.

• Power supply. Simple and flexible system. The plant needs a feeding system that is versatile and can be adapted as required. The plant must be able to accept pasty, liquid or solid waste and have an inert waste separation area. It must also be adaptable to an industrial feed, by shovel loader or conveyor, such as you would have if you were processing waste from a continuous industrial process. The design of the first version of the feeding system has been one of the most resource-consuming aspects.

• Ability to expand by adding additional processes. Sufficient space is sought for later additions and improvements, such as sanitisation or sterilisation processes. This may allow the plant to be expanded if it is of economic interest. AGF PROCESOS BIOGAS SL has delivered the first pig carcass sterilisation plant SANDACH C2 by Method 1 in Spain. This technology is already proven and can be integrated into the MPB. More information about the sterilisation plant will be provided in future posts of this blog.

• Top quality equipment, similar to that of an industrial plant. In order to have a reliably operating plant, top quality equipment must be available. Therefore, the MPB must have the same capabilities as an industrial plant in terms of equipment, valves, piping and instrumentation. Therefore, the design will seek to provide the plant with all the capabilities of an industrial plant.

• The plant must operate without storing gas. Gas should be produced as it is consumed, without the need to store gas produced in a period where consumption is lower than production. Saving on the investment needed for the gas storage is essential to contain the investment cost and footprint of the plant. In addition, gas storage facilities are risks elements in any installation. This is one of the main challenges for the plant.

• Do not use plastics. In existing plants, a large part of the pipes, external and internal, are usually installed in plastic materials. This does not mean an effective reduction in cost compared to the installation with more noble materials, as the reduction in cost per linear metre is offset by the high cost of the fittings; and it also means the possibility of dismantling and changing, which gives the whole design an aspect of provisionality that is not considered desirable. Plastic pipes also encourage modification and change installations, which is considered to be far from a definitive process and a quality installation. For this reason, all MPB pipes are made of high quality stainless steel. The installation of high quality piping allows working with superheated fluids and ensures the correct operation of the plant.

• Not aditions elements in the final ubication. Indepenently of any improvements to be made to the final location, the site requirements should not exceed a base and the supply of the necessary services (water and/or electricity) and the evacuation of energy where appropriate, either in the form of gas, or transformed into electricity and/or thermal fluid.

• Maritime shipping capability. As the MPB is considered a product of special interest to developing countries, the entire design is engineered for possible delivery by sea transport to any port and subsequent delivery to any part of the world.

• Easy assembly in the field. As no require any external installations and all the elements are tested in the workshop, no complex connection and implementation work is necessary. This should allow the plant to be started up quickly, as soon as it is received at its destination, connected and operational, avoiding connection problems in the field and as quickly as possible.

• CE marking of the instalation. There is no need for complex on-site assembly, and everything is designed and assembled in the workshop, the MPB can be supplied with a CE marking and a HAZOP assessment of compliance with all legal requirements in terms of safety.

• The fact that it can be mass-produced should also reduce investment costs. The aim is to have 6 plant models combining different feeding systems and different uses of gas. If the design does not have to be adapted, it will be possible to industrialise its assembly and have a controlled investment cost each time.

• Design that can be patented or intellectually protected. We are looking for a design of a process or product sufficiently novel to be able to proceed to its intellectual and industrial protection by AGF PROCESOS BIOGAS SL as its developer.

5. Low operating cost.

The cost of operation is closely related to the design. Estimates made during design are considered to be within an affordable range, although they will have to be studied in the first prototype. Labour costs may be the biggest burden on the plant, so it is designed with a high degree of automation, with the operator only feeding the plant, the rest being automatic and controlled remotely by AGF’s Operations Centre (COP) team.

AGF PROCESOS BIOGAS SL will offer the remote operation service of the plant. The delivery of the plant is the beginning of the real relation between the parts, as AGF does not want the developer to be left to his own devices with an installation that he does not control, and to which he is obliged to dedicate time and effort.

6. New uses of gas. Renewable has production.

The MPB plant has possible uses as a renewable energy generating facility. It is capable of generating electrical and/or thermal energy, but it can also be capable of producing renewable gas as an energy vector for later use. Due to the current state of the sector, where all installations are mostly intended for electricity production, it was decided to try to make a technological leap and will try to develop the most complex case: producing biomethane.

For this purpose the enrichment plant, the PE 3 BM10, has been developed, which combined with the MPB will give the commercial product of the MP2B, Mini Biogas and Biomethane Plant.

Producing electrical energy or heat is an old, simple, and valid use that can have a wide market. Making a gas separation process at low pressure and in a low-cost installation is a technological challenge. The development of the MiniBiogas Plant with a biomethane plant is a great leap forward in the sector. This gas separation plant does not expect to reach biomethane concentration values for use in the natural gas network, but for vehicle use or distribution to a nearby consumption point.

The process to be carried out in this installation is new, and seeks the point of greatest solubility separation between the different gases to be separated. The design of this PE3 BM10 enrichment plant has been carried out with the aim of not overcoming a certain investment cost, which is why it was not possible to work at moderate or high pressures.

The operation of this enrichment plant and the process it carries out will be one of the main objects of study of the pilot plant, in this first constructed version. If the MPB is able to comply with the main design requirements previously collected, it will be possible top ut on the market a biogas plant that can contribute to relauching the small organic waste management sector, as it will be able to generate an energy vector that can be valorised at the highest possible price and in its entirety.

It was decided not to install a cogeneration unit for electricity production, and to dedicate the space and investment to the prototype version of the PE3 BM10, the low-pressure enrichment plant.

Project status.

Once the objectives have been set, the engineering development process and the execution of the project must be carried out. AGF PROCESOS BIOGAS SL has the necessary capabilities to be able to develop this product until it is marketed and marketed. The design process and the whole assembly of the plant will be developed in the next entries of this blog.

In the plot where this project it is going to carry out  the necessary works to be able to receive the plant.