Roman Hackl

Total Site Analysis (TSA) and Exergy Analysis for Shaft Work and Associated Steam and Electricity Savings in Low Temperature Processes in Industrial Clusters

Low temperature process cooling is an energy demanding part in many chemical production processes. Cooling systems operating at very low temperatures consume a large amount of high quality energy such as electricity or high pressure steam, used to drive refrigeration compressor units. Hence decreasing refrigeration load can make a major improvement on the process energy balance. In industrial process clusters with several processes operating at low temperatures, it is important to investigate opportunities for exchange of low-temperature energy between processes. This paper presents an investigation for a chemical cluster located in Stenungsund on the West Coast of Sweden. One chemical plant within the cluster operates two compression refrigeration systems at its steam cracker plant. One system is a propylene-based system with three temperature levels between 9 °C and -40 °C, driven by high pressure steam turbine drivers with a capacity of ca. 22 MW. The other is an ethylene refrigeration system with three temperature levels between -62 °C and -100 °C, electrically driven with a capacity of ca. 4.5 MW. A previous Total Site Analysis (TSA) study of the cluster focused on integration opportunities within the cluster above ambient temperature, thereby decreasing the overall hot utility and cooling water and air demand. Utility savings below ambient temperature were not investigated in detail. This paper demonstrates how Heat Integration (HI) tools such as TSA and exergy analysis can be applied to target for shaft work and hot utility savings for processes and utility systems operating below ambient temperature. In total a savings potential corresponding to 15 % of the total shaft work consumption of the refrigeration systems was identified. In addition ca. 6.3 MW of utility steam which is currently used for sub-ambient process heating can be saved in addition to shaft work savings.

Targeting for Energy Efficiency and Improved Energy Collaboration Between Different Companies Using Total Site Analysis (tsa)

A chemical cluster located in Stenungsund on the West Coast of Sweden is analyzed to determine the total site level energy efficiency opportunities using the Total Site Analysis (TSA) method. The cluster consists of 5 chemical companies, i.e., AGA Gas AB producing industrial gases, Akzo Nobel Sverige AB producing amines and surfactants, Borealis AB producing ethylene, and PE, INEOS Sverige AB producing PVC and Perstorp Oxo AB producing speciality chemicals. The heart of the cluster is a steam cracker plant run by Borealis, which delivers partly feedstock and fuel to the other plants. The overall heating and cooling demands of the site are ∼ 442 and 953 Mw, respectively. TSA is used to stepwise design a site-wide utility system which improves energy efficiency. Utility savings of ≤ 122 Mw can be achieved, plus a steam excess of 7 Mw. Qualitative evaluation of the suggested measures shows that 60 Mw of the savings potential can be expected to be achieved with moderate changes to the process utility system. This is an abstract of a paper presented at the 19th International Congress of Chemical and Process Engineering and 7th European Congress of Chemical Engineering (Prague, Czech Republic 8/28/2010-9/1/2010).

The potential for electrofuels production in Sweden utilizing fossil and biogenic CO2 point sources

This paper maps, categorizes, and quantifies all major point sources of carbon dioxide (CO2) emissions from industrial and combustion processes in Sweden. The paper also estimates the Swedish technical potential for electrofuels (power-to-gas/fuels) based on carbon capture and utilization. With our bottom-up approach using European data-bases, we find that Sweden emits approximately 50 million metric tons of CO2 per year from different types of point sources, with 65% (or about 32 million tons) from biogenic sources. The major sources are the pulp and paper industry (46%), heat and power production (23%), and waste treatment and incineration (8%). Most of the CO2 is emitted at low concentrations ( 90%, biofuel operations) would yield electrofuels corresponding to approximately 2% of the current demand for transportation fuels (corresponding to 1.5–2 TWh/year). In a 2030 scenario with large-scale biofuels operations based on lignocellulosic feedstocks, the potential for electrofuels production from high-concentration sources increases to 8–11 TWh/year. Finally, renewable electricity and production costs, rather than CO2 supply, limit the potential for production of electrofuels in Sweden.

Assessing the aggregated environmental benefits from by-product and utility synergies in the Swedish biofuel industry

ABSTRACT The production of biofuels in Sweden has increased significantly in the past years in order to reduce fossil fuel dependence and mitigate climate impacts. Nonetheless, current methodological guidelines for assessing the GHG savings from the use of biofuels do not fully account for benefits from by-products and other utilities (e.g. waste heat and electricity) from biofuel production. This study therefore reviews the aggregated environmental performance of these multi-functional biofuel systems by assessing impacts and benefits from relevant production processes in Sweden in order to improve the decision base for biofuel producers and policymakers in the transition to a bio-based and circular economy. This was done by (1) conducting a mapping of the Swedish biofuel production portfolio, (2) developing future production scenarios, and (3) application of life cycle assessment methodology to assess the environmental performance of the production processes. Special focus was provided to review the potential benefits from replacing conventional products and services with by-products and utilities. The results provide evidence that failure to account for non-fuel-related benefits from biofuel production leads to an underestimation of the contribution of biofuels to reduce greenhouse gas emissions and other environmental impacts when replacing fossil fuels, showing the importance of their multi-functionality.