This paper quantitatively examines the impact of industrial symbiosis on sustainability. The quantitative approach, as developed by the authors, is based on the concept of Industrial Sustainability Index (ISI), which represents the socio-economic benefit of an industry per unit of its carbon emissions. The ISI was evaluated for a chemical production plant both in independent and symbiotic modes with different energy technologies. The ISI value for the chemical production plant in independent mode was found to be 6 units. This was three times more than in the case of the existing symbiotic mode with an adjacent pulp & paper industry having coal fired CHP plant. With the adoption of more energy efficient technologies e.g. natural gas based combined cycle power plant and solar PV electricity generation; the ISI in the modified symbiotic mode can be increased to 18 units. The results indicate that industrial symbiosis can help in sustainability improvement when the technologies used by the industries are energy efficient.
The Industrial sector involves various types of resource consumption e.g. materials, energy and manpower with associated emissions and wastes. Industrial sector consumed 175.82 EJ of primary energy and contributed nearly 21% (i.e. 15.44 GtCO2) of the total global emissions in 2010 [
Industrial sustainability is an important factor for socio-economic development and environmental protection across the world [
The commonly used metric for assessing energy performance in the industrial sector has been the Specific Energy Consumption (SEC). However, the SEC is variable depending upon the type of industrial product as well as the scale of industrial production [
In order to overcome the above-mentioned deficiencies of SEC and eco-efficiency, a new Industrial Sustainability Index (ISI) was proposed by Pandey and Prakash, 2018 [
The Industrial symbiosis approach is one of the sustainable options that may reduce the overall impact of inter-connected industries. Such an interconnection engages separate industries in a collective approach to provide a competitive advantage by involving physical exchange of materials, energy, water, and/or by-products. Taddeo et al., 2012 [
Berkel et al., 2009 [
The chemical sector is one of the most energy and resource consuming in India [
This study aims to examine the possible improvement of industrial sustainability through the industrial symbiosis of two existing chemical sector industries (i.e. Orient Papers Mills & Hukum Chand Jute Industry) located at Amlai (Madhya Pradesh), India. Generally, it is assumed that the sustainability of the industrial sector would improve with symbiosis. However, it may not be true in all cases, as the impact of symbiosis on sustainability may depend upon the efficiency of various technologies used in energy and material exchange as examined through this study.
For quantitative assessment of industrial sustainability, a new Industrial Sustainability Index (ISI) was proposed by Pandey and Prakash, 2018 [
ISI = ( RVA ) × ( EMP ) CO 2 emissions
where,
The term “RVA” represents the resource value addition (i.e. the difference of the total annual economic values of material & energy outputs (products) and
that of inputs); it’s represented here as million Rs. per year. The limitation of RVA using Indian currency (Rs.) can be overcome if the RVA is represented in US Dollars with purchasing power parity (i.e. PPP $). The use of purchasing power parity can make the RVA units universal in nature rather than being country specific.
The term “EMP” represents the total number of persons employed by the industry in a year; and “CO2 emissions” represent the total annual carbon dioxide emissions by the industry during production (in tCO2/year).
The above-mentioned concept of ISI was applied to a pulp & paper industry [
In order to quantitatively assess the overall sustainability impact of symbiosis, the values of ISI need to be computed for a particular industry, both in the independent mode as well as in the symbiotic mode. If an improvement in ISI value is observed with symbiosis, then only the industry should adopt such a mode.
The above methodology has been applied for the case study examined in this work.
The case study selected for this work is a soda ash chemical industry (Hukum Chand Jute Industry (HJI) located at Amlai (M.P), India), which works in a symbiotic mode with an adjacent pulp & paper industry (Orient Paper Mills (OPM) located at Amlai (M.P), India). The electricity and steam produced by the paper industry supply all the energy needs of the soda ash chemical industry. Further, the chemical industry provides all the chemical feedstocks (i.e. Caustic soda, Liquid Chlorine, and Sodium Hypo Chlorite) required for the pulp & paper industry. Thus both industries get benefited by reduced costs of energy and raw materials. Such symbiosis is depicted in
The chemical production plant of HJI has four major outputs: Caustic Soda Lie, Cl2 gas, Liquid HCl, Sodium Hypo-Chlorite. The raw-material input to the plant is salt, soda ash, and barium chloride. The electrical and thermal energy demands of the industry are met through OPM. The annual electricity generated by the OPM was about 158.4 GWh in the year of 2017. Out of this 71.3 GWh, electricity per year (i.e. 45% of the total electricity generation at OPM) was supplied to the HJI. Only 38 MWh per year of electricity is imported from the grid as an emergency back-up. Saturated steam (bled from the main steam header of the OPM boiler) is supplied to the HJI at 10 - 12 bar and 180˚C - 190˚C for meeting its process needs.
Data regarding the detailed input resource consumption and product outputs of the HJI were collected from the Data and Record Center Office of the HJI industry. This data has been used in the computation of RVA, CO2 emissions, and the ISI as presented in the results.
Prior to 2012, the HJI unit was working in an independent mode in terms of the energy supply. The power needs of the unit were being met through Madhya Pradesh Electricity Board (a state-run utility company), and process steam was generated through a coal-fired boiler. As per the information provided by the HJI, the company’s turnover and employment have been practically the same. Such an independent mode of the unit is depicted in
The detailed input resource consumption and product outputs of the HJI in independent mode are provided in
In the existing symbiotic mode, all the energy (electricity and steam) requirements of HJI are being met through the coal-fired CHP plant of OPM. The material exchange has remained constant between the two units. For this mode, the
annual material and energy consumption data is given in
Thus, the ISI for existing symbiotic mode is less than that in the independent mode. This is due to the inefficient power generation from the coal-fired CHP plant at OPM. The boiler pressure used in the CHP plant is only 65 bar, while power available from the grid is generated with steam from high pressure (~200 bar) boilers. Therefore coal consumption and CO2 emissions per unit of electricity generation from the grid are less than that in the CHP plant.
In order to improve the ISI of HJI in symbiotic mode, the following modifications have been proposed. The electricity generation at the OPM can be made much more efficient by employing a natural gas based combined cycle (NGCC) plant. This can be economically realized through re-powering of the existing coal-based CHP plant. The NGCC plant will have a natural gas fuelled gas turbine plant as a topping cycle and steam generated through a heat recovery steam generator (HRSG) will be used for the steam turbine bottoming plant. Such an arrangement was analysed by Pandey and Prakash, 2018 [
Sl. No. | Item (Input/Output) | Quantity | Price/Cost rate (Rs) | Total Price/Cost (million Rs) |
---|---|---|---|---|
01 | Electricity Import from MPEB Grid (Input) | 71,318,000 kWh | 6.00/kWh | 428 |
02 | Steam consumption (coal based) (Input) | 3932 MT | 3000/MT | 12 |
03 | High-speed diesel (Input) | 10 MT | 52,000/MT | 0.52 |
04 | Salt (Input) | 54,509 MT | 3000/MT | 164 |
05 | Soda Ash (Input) | 70 MT | 20,000/MT | 1.4 |
06 | Barium Chloride (Input) | 216 MT | 100,000/MT | 21.6 |
07 | Caustic Soda Lie (Output) | 34,942 MT | 40,000/MT | 1398 |
08 | Cl2 gas (Output) | 19,037 MT | 15,000/MT | 286 |
09 | Liquid HCl (Output) | 33,396 MT | 10,000/MT | 334 |
10 | Sodium Hypo-Chlorite (Output) | 2081 MT | 5000/MT | 10.4 |
SL.NO. | Item | Quantity | Average Calorific Value (CV) (MJ/kg) | Specific emission factor (kgCO2/kg fuel) [ | Annual CO2 Emissions (tCO2) |
---|---|---|---|---|---|
01 | Coal | 3932 MT | 17.6 | 1.66 | 6527 |
02 | High-Speed Diesel | 10 MT | 35.0 | 2.76 | 27.6 |
03 | Electricity from MPEB Grid | 71,318,000 kWh | - | 0.88 kg CO2 per kWh | 62,760 |
Total Annual CO2 Emissions = 69,314.6 tCO2 |
For this production mode of HJI, the following results were obtained: RVA = 1401 million Rs, Emp = 300 persons, CO2 Emissions = 69,314.6 tCO2, Hence, ISI = 6.0 units.
improvement in ISI for the OPM plant. Such an efficiency improvement will also help in ISI improvement of HJI in symbiotic mode.
Additional improvements and partial fulfillment of electrical demand of HJI plant with solar PV-rooftop system (2 MWp) have also been proposed for further reducing the carbon emissions from HJI plant. The simulation of the solar PV system has been done by the RET screen software. For use of solar PV-rooftop system (2 MWp), the roof area required for the solar collector is 14,545 m2. The electrical energy generated by solar PV-rooftop system in a year is 3062 MWhe.
Sl. No. | Item (Input/Output) | Quantity | Price/Cost rate (Rs) | Total Price/Cost (million Rs) |
---|---|---|---|---|
01 | Electricity Import from MPEB Grid (Input) | 38,000 kWh | 6.00/kWh | 0.23 |
02 | Electricity Import from OPM (coal based) (Input) | 71,280,000 kWh | 6.00/ kWh | 428 |
03 | Steam consumption from OPM (coal-based) (Input) | 3386 MT | 3000/MT | 10.15 |
04 | Salt (Input) | 54,509 MT | 3000/MT | 164 |
05 | Soda Ash (Input) | 70 MT | 20,000/MT | 1.4 |
06 | Barium Chloride (Input) | 216 MT | 100,000/MT | 21.6 |
07 | Caustic Soda Lie (Output) | 34,942 MT | 40,000/MT | 1398 |
08 | Cl2 gas (Output) | 19,037 MT | 15,000/MT | 286 |
09 | Liquid HCl (Output) | 33,396 MT | 10,000/MT | 334 |
10 | Sodium Hypo-Chlorite (Output) | 2081 MT | 5000/MT | 10.4 |
SL.No. | Item | Quantity | Average Calorific Value (CV) (MJ/kg) | Specific emission factor (kgCO2/kg fuel) [ | Annual CO2 Emissions (tCO2) |
---|---|---|---|---|---|
01 | Coal | 127,252 MT | 17.6 | 1.66 | 211,238 |
02 | Furnace Oil | 589 MT | 42.0 | 3.31 | 1950 |
03 | High-Speed Diesel | 6.9 MT | 35.0 | 2.76 | 19 |
04 | Charcoal | 0.43 MT | 29.0 | 2.30 | 0.98 |
05 | Electricity from MPEB Grid | 38,000 kWh | - | 0.88 kg CO2 per kWh | 33.44 |
Total Annual CO2 Emissions = 213,241.4 tCO2 |
For this production mode of HJI, the following results were obtained: RVA = 1403 million Rs, EMP = 300 persons, total annual CO2 emissions = 213,241 tCO2. Hence, ISI for the existing system is evaluated as 2.0 units.
The above two modifications in symbiotic mode are depicted through
Sl. No. | Item (Input/Output) | Quantity | Price/Cost rate (Rs) | Total Price/Cost (million Rs) |
---|---|---|---|---|
01 | Electricity Import from MPEB Grid (Input) | 38,000 kW | 6.00/kW | 0.23 |
02 | Electricity Import from OPM (Input) | 68,218,000 kW | 6.00/kW | 313.7 |
03 | Steam consumption from OPM (Natural gas consumed) (Input) | 1176 MT | 10,000/MT [ | 12 |
04 | Salt (Input) | 54,509 MT | 3000/MT | 164 |
05 | Soda Ash (Input) | 70 MT | 20,000/MT | 1.4 |
06 | Barium Chloride (Input) | 216 MT | 100,000/MT | 21.6 |
07 | Electricity Produced from SPV (Output) | 3,062,000 kW | 6.00/kW | 18.3 |
08 | Caustic Soda Lie (Output) | 34,942 MT | 40,000/MT | 1398 |
09 | Cl2 gas (Output) | 19,037 MT | 15,000/MT | 286 |
10 | Liquid HCl (Output) | 33,396 MT | 10,000/MT | 334 |
11 | Sodium Hypo-Chlorite (Output) | 2081 MT | 5000/MT | 10.4 |
Sl. No. | Item | Quantity | Average Calorific Value (CV) (MJ/kg) | Specific emission factor (kgCO2/kg fuel) [ | CO2 Emissions (tCO2) |
---|---|---|---|---|---|
01 | Natural gas | 9448.5 MT | 48 | 2.67 | 25,227.5 |
02 | Solar PV | 3,062,000 kWh | - | 0.041 kg CO2 per kWh | 125.5 |
03 | Electricity from MPEB Grid | 38,000 kWh | - | 0.88 kg CO2 per kWh | 33.44 |
Total CO2 Emissions = 25,386.4 tCO2 |
Sl. No. | Production mode of HJI | ISI |
---|---|---|
01 | Independent mode | 6 |
02 | Existing symbiotic mode | 2 |
03 | Modified symbiotic mode | 18 |
The ISI for an improved system of the HJI plant is evaluated as follows: RVA is evaluated as 1533 million Rs, Annual EMP is 300 persons and the total annual CO2 emissions are estimated at 25,386 tCO2. Therefore, ISI for the improved system is evaluated as 18 units.
Hence, with the proposed modified system for the HJI industry, the improvement in ISI of the industry is nearly nine times compared to the existing symbiotic system.
In this study, a quantitative approach for sustainability assessment was used to examine the impact of industrial symbiosis with different technologies. Such an assessment is based on a practical tool of ISI as developed by the authors [
The following conclusions are drawn from the results obtained:
1) The industrial symbiosis can help in sustainability improvement when the technologies used by the industries are efficient and sustainable.
2) With inefficient technologies such as coal-fired CHP plant, it was observed that sustainability could not be improved even in the symbiotic mode. Rather, the ISI value in the independent mode was more because of the more efficient technology used in the grid electric supply.
3) Thus the role of technology in improving industrial sustainability is very significant.
4) By examining the role of energy-efficient and sustainable technologies, one can assess the feasibility of sustainability improvement in the industrial sector.
Similar studies should be carried out for other industries working in a symbiotic mode, not only in India but also at other locations in the world. This would help in a better understanding of the dynamics of industrial cooperation, and facilitate the adoption of appropriate technologies for improving industrial sustainability.
The authors gratefully acknowledge the help and support received from the management of Hukum Chand Jute Industry at Amlai, Shahdol, Madhya Pradesh, India in obtaining the energy use and production data from the plant. The authors also gratefully acknowledge the constructive and useful suggestions by the anonymous reviewers for improving this manuscript.
The authors declare no conflicts of interest regarding the publication of this paper.
Pandey, A.K. and Prakash, R. (2019) Impact of Industrial Symbiosis on Sustainability. Open Journal of Energy Efficiency, 8, 81-93. https://doi.org/10.4236/ojee.2019.82006