WP3
Technical report on industrial symbiosis
Editor and author: Andrea Schüch
Co-Authors: Andreas Hänel, Cecilia Thapper, Audrone Nakrosiene, Mantas Paulauskas, Per Flink, Maggie Lund
Revised version as of 15
thSeptember 2017
Content
1. Introduction 4
2. Definition 4
3. Kinds of industrial symbiosis 4
4. Technical solutions and principles used in industrial symbiosis 6
4.1 Cogeneration/Trigeneration 6
4.2 Heat exchanger 9
4.3 Thermal processes 9
4.4 Incineration and thermochemical conversion 10
4.5 Anaerobic digestion 12
4.6 Material transport systems for symbiosis 14
5. Examples for energy related resources that can be used and converted through
industrial symbiosis 15
6. Technical framework/supporting infrastructure for industrial symbiosis 15
6.1 Heat grid 15
6.2 Gas grids 21
6.3 Other infrastructure 22
7. Best practice examples for industrial symbiosis 22
7.1 Symbiosis through waste exchanges (Type 1) 22
7.2 Symbiosis within a facility, firm or organization (Type 2) 23
7.3 Symbiosis among firms co-located (Type 3) 24
7.4 Symbiosis among local firms that are not co-located (Type 4) 26 7.5 Symbiosis among firms organized virtually across a broader region (Type 5) 27
8. Greenhouse gas mitigation potential 28
9. Conclusions 30
10. Sources 30
Figures
Figure 1. CHP function principle at the example gas utilization (Reference: UNIVERSITY OF
ROSTOCK) ... 8
Figure 2. Absorption refrigeration (Reference: GDANSK UNIVERSITY OF TECHNOLOGY) ... 8
Figure 3. Tubular Heat Exchanger Design – Double Flow (Source: http://www.alternative- energy-tutorials.com/energy-articles/heat-exchanger-design.html) ... 9
Figure 4: Lindal diagram of temperature ranges for thermal processes and its possible uses (Reference: GDANSK UNIVERSITY OF TECHNOLOGY) ... 10
Figure 5. Thermal processes (Reference: UNIVERSITY OF ROSTOCK) ... 11
Figure 6. Supply chains of biogas production (Reference: FNR) ... 13
Figure 7. Definition of surplus heat ... 16
Figure 8. Possibilities to use surplus heat. ... 17
Figure 9. Temperature categories of surplus heat. ... 18
Figure 10. Screenshot of the German IHK-Platform for material or waste exchange for recycling (Source: ihk-recyclingboerse.de) ... 22
Figure 11. Kalundborg Symbiosis 2015 (Source: Kalundborg Symbiosis). ... 24
Figure 12. At the left side the MBT, at the right the RDF-Heat and Power plant, between the plants the heat/steam and material pipe, above the connection to the heat grid of the industrial site Rostock Port (Source: Google Maps 2017, GeoBasis-DE/BKG (© 2009)) ... 25
Figure 13. Example from Industry Park of Sweden (IPOS) ... 26
Figure 14. Net contribution of the disposal methods to global warming of one ton waste [Voigt et al. 2015] ... 29
Tables Table 1. Kinds of CHP according to the power output [Carbon Trust 2010] ... 7
Table 2. Furnaces for solid fuels and range of operation ... 11
Table 3. Comparison of net emission factors for material recovery [Voigt et al. 2015] ... 29
Contributions of the authors
Andrea Schüch: Editing, Chapters 1-3, 4.4-4.6, 5, 6.2-6.3, 7.1, 7.2, 7.5, 8-10 Cecilia Thapper: Contributions in all chapters, proofreading
Andreas Hänel: Chapters 4.1-4.3, 6.1.1 Maggie Lund: Chapter 7.3
Per Flink: Chapters 4.6, 7.4
Audrone Nakrosiene, Mantas Paulauskas: Chapter 6.1.2
1. Introduction
The aim of the European project "UBIS - Urban Baltic Industrial Symbiosis" (partly funded by the INTERREG South-Baltic Programme) is to promote industrial symbiosis in the
participating regions and to implement pilots, where material and energy streams are sustainably reused and to reduce emissions at the same time. Even if a lot has already been achieved in this area, there are still many unused material flows and there are possibilities to use them even more efficiently. In the project existing collaborations will be investigated as well as new ones identified and evaluated.
Aim of the study “Technical report on industrial symbiosis” is to collect best practices on technical solutions, including different energy related resources that can be used and converted through industrial symbiosis. It provides an insight into the subject of industrial symbiosis as well describes established examples for industrial symbiosis. The purpose is to build a theoretical framework around industrial symbiosis that can be developed and used by all partners in cooperation and that will be used in order to identify local sites with symbiosis potential later on.
2. Definition
The term industrial symbiosis is used when traditionally separate companies and industries work together in a collective approach to physically exchange energy or materials (e.g.
water, by-products) with a mutual competitive advantage.
“Industrial symbiosis is part of a new field called industrial ecology. Industrial ecology is principally concerned with the flow of materials and energy through systems at different scales, from products to factories and up to national and global levels. Industrial symbiosis focuses on these flows through networks of businesses and other organizations in local and regional economies as a means of approaching ecologically sustainable industrial
development. Industrial symbiosis engages traditionally separate industries in a collective approach to competitive advantage involving physical exchange of materials, energy, water, and/or byproducts. The keys to industrial symbiosis are collaboration and the synergistic possibilities offered by geographic proximity.” [Chertow 2008, updated: 2012]
3. Kinds of industrial symbiosis
After Chertow (2012): “There are three primary opportunities for resource exchange:
1) Byproduct reuse, surplus energy use or the exchange of enterprise specific materials between two or more parties for use as substitutes for commercial products, raw materials or fossil fuels. The materials exchange component has also been referred to as a byproduct exchange, byproduct synergy, or waste exchange and may also be referred to as an
industrial recycling network.
2) Utility/infrastructure sharing the pooled use and management of commonly used resources such as energy, water and wastewater.
3) Joint provision of services meeting common needs across firms for ancillary activities such as fire suppression, transportation and food provision.
In general, industrial symbiosis occurs locally or regionally across participating companies.
Increasing the distance among firms lessens the breadth of exchange opportunities because it is not cost effective to transport water and steam beyond regional boundaries, whereas byproducts can often travel much farther.”
Chertow (2012) devised a taxonomy of materials exchange types: through waste exchanges (type 1); within a facility, firm, or organization (type 2); among firms co-located in a defined ecoindustrial park (type 3); among local firms that are not co-located (type 4); and among firms organized ‘‘virtually’’ across a broader region (type 5).
In the following, these types are described [Chertow 2012]:
Type 1: Through Waste Exchanges: Most often focused at the end-of-life stage of a product or process, examples of these exchanges would include contributions of used clothing for charity and collection of scrap metal or paper by scrap dealers or municipal recycling programs. Waste exchanges formalize trading opportunities by creating hardcopy or online lists of materials that one organization would like to dispose of and another organization might need. The scale of trades can be local, regional, national, or global. The exchanges accomplish various input/output savings on a trade-by-trade basis rather than continuously.
They feature exchange of materials rather than of water or energy.
Type 2: Within a Facility, Firm or Organization: Some kinds of materials exchange can occur primarily inside the boundaries of one organization rather than with a collection of outside parties. Large organizations often behave as if they are separate entities and may
approximate a multiform approach to industrial symbiosis. In the context of state-owned enterprises common in Asia, material exchanges can extend along the supply chain of a product still under single ownership.
Type 3: Among Firms Co-located in a Defined Ecoindustrial Park or industrial site: In this approach, businesses and other organizations that are contiguously located can exchange energy, water, and materials and can go further to share information and services such as permitting, transportation, and marketing. Type 3 exchanges occur primarily within the defined area of an industrial park or industrial estate, but it is also common to involve other partners "over the fence." The areas can be new developments or retrofits of existing ones.
Type 4: Among Local Firms That Are Not Co-located: Partners in this type of exchange need not be sited adjacent to one another but rather are located within a small geographic area.
Type 4 exchanges draw together existing businesses that can take advantage of already generated material, water, and energy streams and also provide the opportunity to fill in new businesses based on common service requirements and input/output matching.
Type 5: Among Firms Organized Virtually across a Broader Region: Given the high cost of moving and other critical variables that enter into decisions about corporate location, very few businesses will relocate solely to engage in industrial symbiosis. Type 5 exchanges depend on virtual linkages rather than colocation. Although still place-based enterprises, type 5 exchanges encompass a regional economic community in which the potential for the identification of byproduct exchanges is greatly increased by the larger number of firms that can participate. An additional attractive feature is the potential to include small outlying agricultural and other businesses. Self-organized groups, such as the network of scrap metal dealers, agglomerators, and dismantlers that feed particular mills and subsystems (e.g., auto recycling), could also be considered as type 5 systems.”
In Chapter 7 different best industrial symbiosis practice examples, mainly in the South Baltic Region, are collected, sorted by the given types 1 to 5.
4. Technical solutions and principles used in industrial symbiosis
4.1 Cogeneration/Trigeneration
Cogeneration is the simultaneous production of heat and electrical power, whereas trigeneration additional supplies cooling by connecting the cogeneration system to an absorption chiller. Depending on the generated output the following terms are used:
combined heat and power (CHP) or combined cooling, heat and power (CCHP) plant. Within the cogeneration systems fuel is converted to mechanical and thermal energy, which is further converted into electrical energy. The system rejects low-temperature heat, which is used for heating and/or cooling of commercial, industrial or residential units. Due to the theoretical Carnot cycle, every classical thermodynamic engine is subjected to efficiency limits, when heat is converted to work or conversely. Considering equation (1) it becomes obviously, that cogeneration/trigeneration achieves high efficiencies, since different kinds of output energies are used.
ߟ ൌ ೠ
ൌ (1)
The procentual output energy distribution is as following: 40-48% electricity, 35-45%
heat+cooling, 10-15% looses [Clark Energy 2017]. In order to reduce transportation and distribution losses and make cogeneration economically feasible, the plants should be close to the end user. The following fuels can be used: natural gas, biogas, landfill gas, burnable process gas, biomass, coal, petroleum products, and municipal waste.
Depending on the generated power, different sizes can be distinguished (see Table 1).
The basic elements of CHP systems are the prime mover, electric generator and the heat
recovery unit. Different types of prime movers can be distinguished [Ellamal 2015, REH 2017]:
● Internal combustion engines (e.g. Otto engine),
● External combustion engines (e.g. Stirling engine, steam engine),
● Gas turbines,
● ORC’s (Organic Rankine Cycles),
● CCGT’s (Combined cycle gas turbines),
● Fuel cells,
● Microturbines.
Table 1. Kinds of CHP according to the power output [Carbon Trust 2010]
Name Application Electrical power
[kW]
Thermal power [kW]
Large CHP large industry > 1,000 not defined
Small CHP (Mini-CHP)
small industrial sites, buildings community heating schemes
25 – 1,000 (< 50)
not defined
Micro-CHP domestic and small commercial sites
< 11 < 70
Nano-CHP single house 1-6 < 30
Especially for Micro- and Nano-CHP systems, the fuel cells, internal combustion or Stirling engines are suitable. In comparison to all other technologies, the fuel cell CHP systems do not need a generator, since electricity is directly generated in the cell by electrochemical reaction. Fuel cells offer the highest electrical efficiency (30-45%), however applied catalysts for the reaction increase the cost significantly. In internal combustion engines the burned fuel yields directly the mechanical motion, whereas the Stirling engine can be driven by various external heat sources and the mechanical motion is caused by a closed working fluid in the engine. Stirling engines generally exhibit a higher performance and reliability than internal combustion engines, however due to the low temperature levels at domestic applications only marginal efficiencies of 6-8% are achieved [REH 2017]. In comparison to internal combustion engines the Stirling engines are superior for CHP applications, when low noise emission and mainly heat generation is required. The ratio of electricity to heat
generation of Stirling and internal combustion engine is 1:6 and 1:2.5, respectively.
The basic principle of a CHP, working with a gas engine is shown in Figure 1. This CHP concept is used for the heat and power production from biogas. Like it was mentioned earlier, waste heat can be used for refrigeration using an absorption refrigerator. The basic principle is shown in the Figure 2. Similar to compressor refrigerators, a refrigerant with a low boiling point is used, which provides the cooling effect due to its evaporation. In the
case of absorption refrigerators, ammonia-water or water-lithium bromide mixtures are commonly used. The main difference between an absorption refrigerator and compressor refrigerator is the way of changing the pressure in the system. In compressor refrigerator it is achieved mechanically, while in absorption refrigerators the pressure change is achieved by heat exchange in the absorber and generator. In the absorber, gaseous refrigerant is absorbed in a solution and passes over into the liquid phase with simultaneously lowering the pressure. In the generator, the refrigerant is casted out from the concentrated solution by waste heat. Since gaseous refrigerant is generated, the pressure is increased.
Figure 1. CHP function principle at the example gas utilization (Reference: UNIVERSITY OF ROSTOCK)
Figure 2. Absorption refrigeration (Reference: GDANSK UNIVERSITY OF TECHNOLOGY)
4.2 Heat exchanger
The establishment of heat exchanging networks is common practice in industry to reduce utility costs. The basic idea is to recover heat by transferring it from one stream to another instead of using external heating or cooling by which heat energy would be dissipated.
Types of Heat Exchanger Design:
1. Tubular and Shell Heat Exchanger Design 2. Double Pipe or Hairpin Exchanger Design 3. Flat Plate and Fin Exchangers
4. Radiators and Solar Exchangers 5. Spiral Heat Exchangers
6. Air Coolers, Chillers and Condensers 7. Wet Cooling Towers
Figure 3. Tubular Heat Exchanger Design – Double Flow (Source: http://www.alternative-energy- tutorials.com/energy-articles/heat-exchanger-design.html)
4.3 Thermal processes
Depending on the temperature level, excess heat can be used for different kinds of thermal processes. A comprehensive overview is given by the Lindal diagram (see Figure 3). Heat is commonly transported in form of steam or hot water and can be used for:
● Drying,
● Evaporation of solvents or water,
● Crystallisation,
● Refrigeration, and
● Heating.
Temperatures above 100°C can be used for the evaporation of solvents or water, like it is needed for crystallization, thickening or drying processes. At low temperature levels, the
heat is mainly used for warming and heating. Like it can be seen in the Lindal diagram (Figure 4), the electric power generation is only feasible at temperatures when the working fluid can be steamed. Heat pumps are only used to transfer heat from a low temperature source to a target system.
Figure 4: Lindal diagram of temperature ranges for thermal processes and its possible uses (Reference:
GDANSK UNIVERSITY OF TECHNOLOGY)
4.4 Incineration and thermochemical conversion
Thermal conversion processes could be divided into the groups incineration, gasification and pyrolysis and results in different products from solid to gaseous (see Figure 5). The
conversion is running under different process conditions in terms of temperature and pressure.
Figure 5. Thermal processes (Reference: UNIVERSITY OF ROSTOCK)
The incineration is a state of the art technology with a broad variety of capacities and adapted technologies (see Table 2).
Table 2. Furnaces for solid fuels and range of operation
Furnace Thermal capacity range
Fuels Water content [%wt]
Under-feed stoker 10 kW - 2.5 MW wood chips with <
1% ash content, pellets
5 - 50
Moving grate 150 kW - 15 MW all types of solid fuels, ash content
up to 50%
5 - 60
Direct firing 2 MW - 10 MW particles << 5 mm mostly <20%
Bubbling fluid bed 5 MW - 15 MW particles < 10 mm 5 - 60 Circulating fluid
bed
15 MW - 100 MW particles < 10 mm 5 - 60 Coal firing up to 1 GW particles < 2- 6 mm < 20
As gasification fluid air or steam could be used. The energy for gasification process is generated by partial oxidation of the fuel. Advantages are: an energy-rich gas is produced, which can be utilized in a CHP-process and further upgrading of synthesis gas to platform chemicals or biomass- to- liquid (BTL) fuels by means of Fischer-Tropsch-Synthesis is
possible. Stage of development: The Fischer-Tropsch (FT) process was developed in Germany in 1925 to produce lubricants and fuels from non-petroleum feedstocks such as coal, natural
gas, and biomass. The challenge is to implement a “tar free” process. Fischer-Tropsch demonstration and pilot plants to synthesise the gas are implemented but not
commercialized. Gasification with following thermal or CHP use, are state of the art.
The hydrothermal carbonisation (HTC) and hydrothermal liquefaction (HTL) are particular types of pyrolysis at elevated pressure. The wet biomass (water content 60 to 80%) is heated at Oxygen exclusion at temperatures from 180 to 300 °C and a pressure up to 40 bar. The retention time is 4 to 12 hours. These technologies are suitable for biomass and biowaste with high water content, e.g. sewage sludge.
Stage of development: batch-process is currently introduced in industrial scale, for biowaste still pilot scale. Continuous processing introduced in pilot scale.
The torrefaction is particular type of pyrolysis where the biomass is heated at Oxygen exclusion and temperatures approx. 200 to 300 °C. Volatile, lower calorific compounds and water are evaporated. The lower heating value (LHV) of the biomass is increased and the combustion characteristic is improved. This technology is suitable for: woody biomass and lignocellulosic biowaste with approx. 50% water content.
Stage of development: process in pilot phase.
4.5 Anaerobic digestion
The production of biogas, the anaerobic degradation of organic material, is one option of energy production from biomass. A large variety of biodegradable substrates is suitable for the production of biogas. To these belongs beside energy crops different organic wastes.
Especially because of the competitive situation between food and energy production the use of by- and waste products has to be assessed in a positive way [Elberg 2012]. The anaerobic digestion (AD) covers the required treatment of these wastes and energy production at the same time. Figure 6 illustrates the supply chains of biogas production.
Organic waste products, e.g. organic wastes from household and business or catering wastes are suitable for the biogas production. The collection is carried out via the regular waste collection. In case of a separated organic waste collection the pre-treatment is substantially reduced compared to a non-separated collection. Especially the storage of organic wastes should be realized as an enclosed building to minimize emissions (odour, noise, gas, liquids etc.). The exhaust air has to be treated specifically.
For a save use of the end products a sanitation/hygienisation step is necessary (at pre- or post-treatment). Hygienisation of biogas substrates is defined as heating the biomass up to 70°C with a residence time of one hour. This method is used for hygienically critical material, such as slaughterhouse waste, catering wastes etc. The hygienisation takes often place prior to fermentation.
Figure 6. Supply chains of biogas production (Reference: FNR)
The process of anaerobic digestion can be distinguished by four typical parameters: dry matter (dm) content, feeding system, Number of process phases and temperature range.
The dry matter content affects the consistency/viscosity of the contents of the fermenter as well as the capability of the substrate mixture to be pumped. The so-called ”wet
fermentation” is defined as the digestion of pumpable input with a maximum dm content of 15%. This type of digestion can mainly be found for food waste or industrial/commercial organic waste. The so-called ”dry fermentation” or ”solid-state fermentation” uses
substrates with a dm content starting at 30%, where the substrate is stackable. This type of digestion applies to the use of green waste. The plug flow technology can work with a dm content > 15% and is often used for municipal biowaste.
Depending on the feeding system of the fermenter the biogas plant can be defined as a continuous or a discontinuous plant. The discontinuous operation mode, also known as batch operation, is mainly utilized for dry fermentation, where several containers are alternately fed. As a result a constant gas production and quality can be ensured. The
prevailed operation is the continuous operation mode. The fermenter is fed regularly several times a day. After the start phase, in which the plant is start up a constant gas building is ensured.
The anaerobic digestion process consists of two phases or steps, if the biological steps of hydrolysis (and acidogenesis) and methanation, with the specific demands on environmental
conditions, e.g. pH-value, are separated, that means the decomposition of macromolecules is located upstream from methanation. If all phases of biological degradation take place in one container, the process is called one phase.
The temperature range is also important for the AD. The psychrophilic temperature range (<
25°C) does not lead to a high degradation and gas building capacity of the process. It is therefore not suitable for a business orientated plant. Most biogas plants operate in a mesophilic temperature range (37°C to 42°C). It is the optimum temperature for a stable methane bacteria growth and hence for gas building as well. The thermophilic degradation at a range of 50°C to 60°C show fast degradation rates compared to mesophilic temperature range but also has the tendency for higher instability.
With regard to the composition of the contents of the biogas produced during digestion, named CH4, CO2, H2S, water vapor and other, a treatment of the gas is necessary to allow a subsequent use. The various utilization paths require different types of treatment and upgrading. For use in a CHP unit the dewatering and desulphurisation is necessary, for use as fuel the CO2-removing and when feeded into the natural gas grid further steps as
conditioning in terms of pressure and heating value for final adjustment to natural gas quality.
The biogas upgrading has different advantages:
1. spatial separation of biogas production and biogas utilisation, because the biogas production takes place close to substrates (rural areas) while the biogas utilisation is possible close to places with high heat and power demand (urban regions)
2. biomethane as fuel for vehicles, in gaseous or liquified form.
The upgrade of biogas to biomethane is limited by economic feasibility. In Germany this is the case for plants with a production of 500 m3 biogas per hour (equivalent to 1 MWel capacity). Sweden has a long-term tradition with biogas upgrade and use in the transport sector.
For co-located industrial symbiosis the use of surplus heat from the cogeneration of biogas is interesting, as well as the use of waste streams for anaerobic digestion.
4.6 Material transport systems for symbiosis
The material transport system depends on the characteristics, amount and material flow (constant, seasonal …) and the distances. Often a transport by trucks at the street is used, caused by long distances and low or changeable amounts or different/changing exchange partners (e.g. recyclables). When the distance to a symbiosis partner is not too large other systems are suitable. These could be pneumatic systems, pipes (for wet/liquid materials) or a conveyer band for lumpy/chunky materials.
One successful example of using pipes to transport material, have been in use between the biogas plant Söderåsens Bioenergi at Wrams Gunnarstorp in Bjuv and the waste water treatment plant at a nearby food industry, in which the most important substrate for the
plant has been transported. The sludge, that has a dry matter content of 2 – 4 %, has been pumped from the industry through a 2 km long pressure line and pumping has been carried out with electric pumps.
5. Examples for energy related resources that can be used and converted through industrial symbiosis
CO2 the waste/by product of conversion processes as incineration,
purification/liquefaction of biogas or natural gas (at food quality for food industry/
beverages; at technical quality for cooling processes; source for power-to-gas concepts; … H2 produced by surplus electricity (e.g. hydrogen network in the industrial site Hamburg for the chemical industry; energy source for power-to-gas concepts)
CNG/LNG based on biomethane from biodegradable wastes (e.g. land power for cruising ships at the Hamburg harbor; fuel for ferries between Sweden and Germany; fuel for transport sector in Sweden; plans for an European LNG fuel station exists)
6. Technical framework/supporting infrastructure for industrial symbiosis
6.1 Heat grid6.1.1 Heat exchanging networks
Instead of using heat exchanging networks only in one plant, industrial symbiosis goes ahead and heat exchanging network is established between different plants. Commonly, such networks consist of heat exchangers, fluid mechanical equipment and attachments. The challenge of optimisation is that with reduction of utility costs investment costs increase [VDI Heat Atlas 2010]. Thus, the best solution is where the total cost is at minimum or where the investment cost quickly amortise. Several methodologies exist designing heat
exchanging networks [VDI Heat Atlas 2010]:
● Pinch method,
● Mathematical programming,
● Stochastic or heuristic algorithms such as genetic algorithm,
● Simulated annealing algorithm, and
● Tabu search procedure.
6.1.2 District heating network
Surplus of industrial heat: It is energy recovered from a production process – energy used for heat. There is a big potential in energy savings in surplus of industrial heat. Figure 7 below explains the surplus of heat.
Figure 7. Definition of surplus heat
Basic principles of utilizing surplus heat:
• Temperature level(s) and duration.
• Enthalpy flow (thermal power).
• Medium and phase of the flow.
• Chemical properties and purity of the medium.
Even if only one of the factors is unfavourable it may be impossible to use the surplus heat. If there is great potential in the surplus heat it may be useful to check the possibilities how to tackle the unfavourable factor. How to approach surplus heat? First of all it is important to check that all the existing heat recovery systems are working properly and efficiently.
Process operation values may have changed since the installation time and that may be one of the reasons why heat is wasted. This gives also possibilities to check if surplus heat can be used more efficiently by improving the current installation by for example by adding some measurements and updating the automation system. Sometimes the simplest way to use surplus heat is to make changes in pipe connections and using heat exchangers.
Heat from processes etc. can be used as secondary energy in the same or some other processes. This can simply be done for example by changing the pipe connections of the
process flows or by updating the process automation.
It is useful and necessary to approach the finding and use of surplus heat in a systematic way. Pinch analysis is one way to approach this problem. Pinch analysis is a systematic method to analyze cooling and heating needs of a plant. The analysis gives answers to the following questions:
• What part of the need for energy can be covered by internal use of heating and cooling energy and how much has to be brought from outside?
• What kind of heat exchanger network is needed?
• What is the theoretical minimum for heating and cooling?
The greatest benefits of such analysis are that energy saving possibilities is found, partial optimization is avoided and knowledge of the process is improved. On the other hand the analysis very laborious and needs lot of time to perform.
Pinch analysis gives best results in plants where lots of energy is used, the process is continuous and the instrumentation is comprehensive. Pinch analysis gives poor results if any when there are batch processes, production varies a lot and instrumentation is inadequate.
If Pinch analysis does not lead to any process changes or it does not give any good alternative then next step has to be taken, Figure 8.
Figure 8. Possibilities to use surplus heat
There may be need to use a heat pump or thermo compressor, or mechanical or by drying fuel material to use surplus heat economically. There are several types of heat pumps, mechanical heat pump, absorption heat pump, mechanical vapour recompression (MVR) and term compressor. They have different properties and areas of operation.
Since all industrial cases are different from one another, examples how to use surplus heat are following.
Example 1. Heat sinks outside plant limits. When a plant has plenty of surplus heat that it cannot be used inside the plant limits it is usually possible to consider selling the surplus heat to neighboring company or community. There are basically three ways how to deal with this possibility, by selling the surplus heat:
• as district heat to a local district heat company
• to enterprises nearby
• to new business company for e.g. biofuel drying.
If there is no community or neighboring plants nearby it is usually not possible to sell surplus heat due to big investment cost in pipe lines. A new plant for drying biomass could then be a very lucrative possibility as biomass is becoming more and more popular fuel.
Temperature levels have to be identified so that surplus heat can be utilised properly.
Temperature levels can be divided into four categories according to how the surplus heat can be used, Figure 9.
Figure 9. Temperature categories of surplus heat
Example 2. Selling surplus heat to other party. It is very important that when surplus heat is sold to other party the terms and agreements are up-to-date and thoroughly checked. There are lots of technical and economical things and contractual relations that have to be
considered and verified before the agreements are signed.
The most important things that have to be agreed technically are:
• Seller: Heat source, temperature levels, peak output, quantity of energy, duration, reliability of delivery and limitations.
• Heat sink, peak input, temperature levels, quantity of energy, duration and limitations.
• Distribution to customers: Temperature and pressure levels, flows.
From the economic and legal point of view there are also several things that parties have to agree on, e.g.:
• Investment cost per party (joint acquisition).
• Tariffs.
• How to change the tariffs, terms etc.
• Length of the term and dismissal
• Maintenance etc.
All of those terms and conditions have to be thoroughly viewed and agreed which takes time, resources and money. The better this work is done fewer difficulties will arise.
Example 3. Drying fuel. Surplus heat can be used as such to (pre)dry biomass fuel or
products. Drying of fuel (biomass, coal etc.) not only improves the heat value of the fuel but flattens the fluctuations in the moisture content and improves the burning conditions and makes the control of the boiler much easier. Also the heat surfaces of the boiler will stay cleaner. These things are very important especially for biomass boilers.
There are several ways to dry biomass. This can be done by a drum dryer, a flash dryer or by a screen dryer etc. All the dryers have the advantages and disadvantages which have to be taken into account when choosing one for the purpose. The most frequently used dryers are drum dryers. The moisture content will drop typically from 50–60 % to 10–30 %. This can lead to 10–15 % savings in fuel cost.
Example 4. High temperature cooling water. An accumulator is attached to area heating network via a heat exchanger in an industrial plant. The purpose of the accumulator is to receive warm water from the process and keep the pipelines open during standstill time in winter. The heat to the heat recovery circuit originates from periodically used processes’
cooling water circuits.
Example 5. Power plant. In power plants auxiliary condensers are used in order to keep the power plant running at the minimum load during disruption in production or during summer time when there is not enough load in the district heating network. By keeping the boiler running it is easy to increase the production rapidly.
Obstacles in utilizing surplus heat
Industrial plants have done a lot of work in energy efficiency and energy savings and benefitted from their work. The driving force behind these efforts has been especially increasing price of energy but also energy efficiency, environmental legislature and equipment development (e.g. heat pumps and automation).
Despite of this progress there is vast amount of surplus heat than can be used economically.
The obstacles in surplus heat utilization can be divided into four categories:
• economic feasibility
• lack or unreliability of proper technology
• lack of proper heat sinks
• obstacles in legislature or in politics or public opinion.
The economic feasibility is the most important factor from the company view. Companies will carry out investments that are not economically sound only if they are force to do so from e.g. environmental reasons. Very tight payback times, quarterly reports and lean organizations are seen as big obstacles in economical use of surplus heat. Energy saving projects are on the same line as production investment projects when money is concerned and due to limitation of the budget there is not always money to energy savings. Energy saving project bring money to the bottom line compared to the production which have to sell the goods before profits are made.
The surplus heat flow may be impossible to utilize because of the difficulties in installation.
The heat flow may be so dirty that it will clog the heat exchanger totally which makes in worst cases the investment totally unprofitable. At least maintenance costs have to be calculated carefully in such cases.
Public opinion is mostly in favor of boosting the use of surplus heat inside the plant or selling it to the community. They see it to be good for the environment because less primary energy is used and this type of utilization can in some way be compared to renewables. The use of surplus heat has almost always positive impact on the surroundings unlike some other forms of energy production (e.g. power plant and wind mills).
6.2 Gas grids
Biogas can be injected and transported in upgraded form as so called biomethane at the natural gas grid. Sometimes it is necessary to transport raw biogas via a micro gas network.
Special requirements have hydrogen pipes. Some aspects of biogas and hydrogen networks are explained in the following.
6.2.1 Biogas lines
A micro gas line, a micro gas network or also a raw biogas line is a connection of the biogas plant with a satellite CHP through a pipeline. This is useful when the biogas and the resulting waste heat cannot be used completely on site. Due to the length of the route and the
resulting heat and pressure losses, the economic viability of a local heating network is often not met. As a rule, most of the generated biogas is fed to the respective consumer via a separate biogas line, where it is energized in a CHP (satellite CHP). The resulting heat is discharged into an adjacent local heating network and sold. Before injection into the pipe the biogas has to be cooled (about 5°C) to dewater it by condensation. This could be done active or by using the cool soil. The water is collected than in special duct. Also a
desulphurization is necessary, mostly done by activated carbon filters.
The necessary heat for the biogas fermenter to maintain the fermentation process can be produced and provided in different ways. To cover the peak loads and as an emergency reserve of the local heat grid (in the event of a fault in the biogas plant), a natural gas or heating oil-fueled emergency boiler is installed. This ensures a secure supply to the heat consumer.
In principle, the cost of pure pipeline construction amounts to 80 to 120 € per meter (in Germany). Depending on the method of installation, whether by plowing, or rinsing, this is more cost-effective or more expensive. The cost comparison makes it clear that the point of the critical track length is about 2,000 meters. From this distance, the operation of a raw biogas line is more economically more sensible than that of a heat line. However, the specific investment and maintenance costs are higher than in the case of a pure heating network, since, in addition to the pipeline, an additional CHP has to be installed and maintained at the site of the heating system. [Vitek 2015]
Another application for a micro raw biogas line could be the joint biogas upgrade of separate biogas plants.
6.2.2 Hydrogen networks
Pipelines for hydrogen are used at industrial sites of the chemical industry and have a long- term tradition. In the framework of the energy transition this concept gains more and more attention to transport energy.
There are also sufficient practical experience with hydrogen pipes in Germany [TüV Süd 2017]: In the Ruhr area, a hydrogen network has been operating for more than 240 km. In Saxony-Anhalt, a 90-km-long, well-developed hydrogen pipeline system from Linde-Gas AG is located in a region with strong industrial gas demand between Rodleben-Bitterfeld-Leuna-
Zeitz.
In Latvia as part of H2Nodes international project in Riga, but also Pernava and Arnhem hydrogen refuelling station for public and private cars will be realized [Baltic news network 2017]
Worldwide more than a thousand kilometers of hydrogen lines existed in 2010. The
transport of energy via a gas network takes place with considerably less losses (<0.1%) than with a power network (8%). [h2works 2017]
6.3 Other infrastructure
Beside infrastructure to transport materials or energy information systems gains more and more important. Examples are: geographic information system (GIS), knowledge exchange or industrial partner search platforms.
7. Best practice examples for industrial symbiosis
7.1 Symbiosis through waste exchanges (Type 1)An instrument in Germany for the exchange of waste for recycling is the “IHK-
Recyclingbörse für Materialien” (IHK-recycling market or materials). This is a non-profit platform maintained by the Chamber of Industry and Commerce. Registered users have opportunity to announce offers and needs anonymously and without costs. The materials are sorted by the categories: chemicals, construction waste, glass, wood, metal, packaging, paper/cardboard, plastic, rubber, textile/leather, composite material, organic waste from animals or plants, others (Figure 7). It could be searched via keywords to find a suitable announce. Since some years the use of the system decreased. Currently only 10 requests and offers are announced per year. Reasons could be: use of other online platforms as e.g.
ebay or already established cooperation for these materials.
Figure 10. Screenshot of the German IHK-Platform for material or waste exchange for recycling (Source: ihk- recyclingboerse.de)
European Recycling Platform (ERP) was founded in 2002 as the first pan-European organization to implement the European Union’s regulations on the recycling of electrical and electronic waste (WEEE Directive). ERP now manages a consolidated network and has developed vast international expertise, expanding its recycling services to include batteries as well as packaging. ERP is the only approved pan-European organization that is trusted by over 2,700 members across Europe and the first in the market offering compliance for WEEE, batteries and packaging in over 32 countries. The mission is to develop high-quality, cost- effective recycling services for the benefit of producer members, consumers and ultimately the environment and society. The network and expertise ensures compliance for producers and importers allowing them to focus on their core business. (http://www.en.erp-
recycling.de/who-we-are/profile/)
7.2 Symbiosis within a facility, firm or organization (Type 2)
The Suiker Unie GmbH & Co. KG operates a sugar factory in Anklam/Germany, the only one in the federal state Mecklenburg-Western Pomerania. Directly connected to the sugar factory, the subsidiary Anklam Bioethanol GmbH runs a bioethanol factory. The main products of the two companies are white sugar and bioethanol from sugar beet. A number of secondary products and waste products are produced. These are partly used in the own company or are marketed as raw materials to other customers. In the first step of the production of sugar or bioethanol, the beet is cleaned and then comminuted. As a result, raw juice is obtained and the leached turnip chips are used as waste material. The wood chips are silted and then used energetically in the company's own biogas plant, in addition to other waste materials such as sludge or similar. Alternatively, the chips are dried and
returned to the beet cultivator, or pressed into pellets under the addition of molasses and then marketed as animal feed. The cleaning of the raw juice is carried out with milk of lime.
After cleaning, the lime is separated and used as a fertilizer in agriculture. The purified raw juice is thickened for crystallization to sugar production and bioethanol production in the connected bioethanol factory. The by-product molasses is produced during crystallization, the production of sugar. The sugar content in molasses is still about 50%. Molasses is used, e.g. to pellet the dry sugar beet chips or directly as a feed additive. Furthermore, molasses is taken from the food industry, rum production, pharmaceutical industry and yeast
production. The produced bioethanol is used in petroleum refineries as an additive. Similarly to sugar production, a large proportion of the waste products from bioethanol production are used in the agriculture. In the fermentation of the molasses the waste product vinasse arises. It can be used either as an animal feed additive, as a fertilizer or biogas substrate. A number of industrial symbioses have developed around the sugar factory in Anklam. The main partner is agriculture. However, other industries can also profit from the waste products of sugar production. [Anonymus 2013]
7.3 Symbiosis among firms co-located (Type 3)
Kalundborg Industrial Symbiosis (see Figure 11) is a well-known – and internationally recognized – example of sustained symbiosis development. Starting in the early sixties, Kalundborg Symbiosis has grown organic over more than five decades with no master plan or top down management. The primary partners are within roughly a 2mile radius of each other. Today, public and private enterprises buy and sell waste products from industrial production in a local cycle. Eight public and private organizations participate in this collaboration. The residual products circulated and traded include water, energy and material that can be physically transported from one enterprise to another. Thus residual products originating from one enterprise becomes the raw materials of another enterprise, benefiting both the economy and the environment.
The symbiosis has produced the following results: yearly CO2 emission reduced by 240,000 tons; 3 million m3 of water saved through recycling and reuse; 30,000 tons of straw
converted to 5.4 million litres of ethanol; 150,000 tons of yeast replaces 70% of soy protein in traditional feed mix for more than 800,000 pigs; and recycling of 150,000 tons of gypsum from desulphurization of flue gas (SO2) replaces import of natural gypsum (CaSO4)4.
Figure 11. Kalundborg Symbiosis 2015 (Source: Kalundborg Symbiosis).
Mechanical-biological Treatment plant (MBT) and Refuse Derived Fuels heat and Power plant (RDF-CHP) at the industrial site Port Rostock, Germany (Figure 12): Here different
exchanges between the two plants are to find. The mechanical part of the MBT generates different material flows from municipal waste for recycling at another place (e.g. metal, glass - Type 1 symbiosis) and for a valuable energetic use (RDF). The biological part produces biogas which is upgraded to biomethane and feeded in the national natural gas grid. The co- located RDF-CHP (Vattenfall) uses the RDF in co-generation and feed per year more than 120,000 MWh electricity into the national electrical grid. The heat is used as steam at the industrial site Port Rostock as well as at the MBT. There the heat is used for technical drying of the remaining organic fraction after the anaerobic digestion to produce RDF with high organic content. The for the incineration at the RDF-plant needed secondary air the ventilation air of the MBT plant is used, which saves there an exhaust air cleaning by bio- filters or air washer. [Vattenfall 2013, Veolia 2017]
Figure 12. At the left side the MBT, at the right the RDF-Heat and Power plant, between the plants the heat/steam and material pipe, above the connection to the heat grid of the industrial site Rostock Port (Source: Google Maps 2017, GeoBasis-DE/BKG (© 2009))
7.4 Symbiosis among local firms that are not co-located (Type 4)
Industry Park of Sweden (IPOS) is built on the belief that Symbiosis is the future. By creating or open up for synergies between companies it will be possible to decrease costs and the impact on the environment and the climate. At IPOS are a number of examples obtained through co-operation and Industrial Symbiosis. All companies on the site share the cost for infrastructures such as roads and the distribution system for energy. Each individual
company thus benefits from lower costs. Products and surplus from the production units are used as raw material for other production lines on the site. This reduces transports. Some synergistic production units are directly joined by pipes. Energy is recovered from
production processes and buildings and reused by the companies. A large amount of recovered energy is also delivered to the Helsingborg municipal district heating grid.
Figure 13. Example from Industry Park of Sweden (IPOS)
The company ReFood distributes kitchen and food waste, superimposed foodstuffs as well as second-hand frying fats from gastronomy, trade and industry. From the waste delivered, ReFood, according to the hygienisation, gains electricity and heat in company-owned biogas plants [ReFood GmbH 2016]. Frying and cooking fats from Malchin and Kogel, located in the Northern part of Germany, are processed and processed in the biodiesel plant of the
company ecoMotion GmbH in Malchin. Every year, 10,000 tons of biodiesel and 1,000 tons of glycerin [ecoMotion 2017] are collected here. By using waste materials to produce biodiesel, 70% of greenhouse gases can be saved compared to fossil diesel [Oehmichen &
Majer 2013]. The waste heat from the biogas plants is used in the company's own operation
to treat the waste. The fermentation residues provide a high-quality fertilizer for agriculture.
Compared to mineral fertilizers, fertilizers from ReFood Dynagar are more sustainable and cost-effective [ReFood 2017]. By processing the waste from numerous customers to renewable energies, renewable fuels and organic fertilizer for the agriculture, ReFood
successfully combines the sectors food industry, retail, gastronomy, industry and agriculture.
7.5 Symbiosis among firms organized virtually across a broader region (Type 5) Specific projects organized in the Triangle J region of North Carolina, in Tampico, and in Alberta sought to identify relevant material and energy inputs and outputs and to match companies within their regions to each other when doing so is economically and
environmentally efficient. [Chertow 2012]
Aims and strategies are summarized in work plans, worked out by the members. Examples of the workplan of TJCOG (Triangle J Council Of Governments) for 2015-2017 are: “Triangle Development & Infrastructure Partnership Strategic Initiatives: The Triangle Development &
Infrastructure Partnership brings together community, university, regional and state
partners to develop long-term, regional strategies for the development and conservation of land, infrastructure investments to support development and improved mobility. The Partnership’s Strategic Initiatives program focuses on four areas: transit investment; water resources planning; capital investment programs; and regional, state and federal
opportunities. Certain initiatives have their own project structure, including: North Carolina Next Generation Networks (NCNGN) NC Next Generation Networks (NC NGN, pronounced
“NC Engine”) is a cooperative effort of universities, their host communities and other partners to speed the deployment of ultra-high speed broadband services for businesses, institutions and consumers.
Energy & Environment Department Planning encompasses green initiatives and sustainable projects in the Triangle and serves as a point of contact for our members as they work to implement green and sustainable initiatives. As a result, the organization is able to take a leadership position in Triangle-area sustainability initiatives. The programs described below comprise the work that member assessments have leveraged. These programs are a collaborative effort of the Energy & Environment Department staff, under the direction of Energy & Environment Program Manager.
Triangle Clean Cities Coalition, founded at TJCOG in 1999, works to improve air quality and reduce dependence on petroleum by promoting alternative fuel vehicles, alternative transportation fuels, hybrids and idle-reduction technology. By bringing together fleet managers, local and state government officials, fuel and vehicle providers and interested citizen groups, the coalition helps move North Carolina toward a more sustainable future.
Waste Reduction Partners: A corps of retired engineers and scientists provides technical assistance to NC industries, businesses, non-profits, institutions and governmental entities.
Technical assistance includes: energy, solid waste and water use reduction assessments to help organizations become more efficient, economically viable and environmentally sustainable. This program operates with a network of more than 60 volunteers across the
state, in partnership with the Land-of-Sky Council of Governments.”
[TJCOG 2014]
A much smaller symbiosis is organised by the Remondis group in Germany. In
Schwerin/Germany a biogas plant feeded by biowaste is running since 2015. The treatment capacity is 18,000 t per year. The at the city area yearly about 7,500 t fresh municipal biowaste is collected. There are various activities to improve the collection, as e.g. public relations activities, free use of bio waste treatment for customers, provision of larger bins, and increase of the provided number of bins. Remondis as part owner of different waste treatment plants acts across a broader region. By an exchange of waste streams within the Remondis group the full capacity of the single participating plants is used. In the case of Schwerin about 10,500 t organic waste from the neighboring federal state is send to the plant. With increasing local collection of biowaste this will decrease. This strategy contributes to a better economically feasibility and flexibility of the participating plants.
[Remondis 2015, SAS Schwerin 2017]
8. Greenhouse gas mitigation potential
Industrial symbiosis generates not only economically advantages of the cooperation companies by saved materials or energy but also greenhouse gas emissions. These savings are reached not only by the avoided transport, avoided treatment and disposal of waste but also by credits from recycling and the substitution of fossil fuels. How much could be saved depends on national default values e.g. for the electricity mix. A detailed study of Voigt et al.
(2015) summarize the different emission factors of the waste management sector.
After this study the transport causes emissions of 24 kg CO2-eq/t waste. The net emissions of the current disposal methods in the EU 28 show Figure 14. The highest loads cause the landfilling, the highest savings the recycling. Table 3 summarize the net emission factors for material recovery. The highest savings could be reached by the recycling of non-ferrous metals followed by the other metals, plastic and paper.
Free tools to calculate the possible savings by recycling are to find at:
http://www.stopwaste.co/calculator/ and https://www.epa.gov/warm/versions-waste- reduction-model-warm#WARM Tool V14.
Figure 14. Net contribution of the disposal methods to global warming of one ton waste [Voigt et al. 2015]
Table 3. Comparison of net emission factors for material recovery [Voigt et al. 2015]
OECD 2012 [kg CO2-eq/t input]
Voigt et al. (2015) [kg CO2-eq/t output]
Fraction America Europe Asia/Pacific all regions
Food waste 50 30 30 8 (-36)*
Garden waste 50 60 60 8
Paper/
cardboard
-550 -820 -820 -793
Plastic -1,680 -1,060 -1,060 -937
Fe metals -1,980 -1,000 -1,000 -945
Non-Fe metals -15,020 -11,100 -11,100 -9,307
Glass -310 -180 -180 -514
* Composting / value in brackets is the net emission factor for anaerobic digestion in the ideal scenario
To calculate the savings by replacing fossil fuels the national default values has to be known.
Depending on the increasing share of renewable energies this changes. Based on IEA (2015) following emission factors for electricity are found [ef 2017]:
- Europe: 0.52995 kg CO2-eq/kWh - Poland: 0.77273 kg CO2-eq/kWh - Germany: 0.4888 kg CO2-eq/kWh - Denmark: 0.30169 kg CO2-eq/kWh - Lithuania: 0.20476 kg CO2-eq/kWh - Sweden: 0.013253 kg CO2-eq/kWh
After Voigt et al. (2015) can for heat from 50% fossil oil and 50% natural a gas emission factor of 0.334 kg CO2-eq/kWh can be used.
9. Conclusions
For industrial symbiosis a broad variety of state-of-the-art technologies are available. Best practise examples show that the implementation is possible and long-term feasible. Main actors are the industries with its knowledge about their material streams and energy needs.
Municipalities can support the implementation of industrial symbiosis by offering of infrastructure for the exchange, information or restrictions. How public authorities can support is described in the project report “Public planning and permits”.
10. Sources
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Elberg, K. (2012): Best Use of Biogas, Important aspects for sustainable RES-Chains, Report project RES-CHAINS, SOUTH BALTIC PROGRAM, June 2012.
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