Process water
Crude palm oil (CPO)
Pretreated feedstock
Other seed oils
(Neutralisation) For high FFA content only
De-gumming Various types
Adsorption
Used cooking oil (UCO)
Chloride mitigation
Polyethylene removal
Boiler feed water
Tallow
Wastewater
Low-grade waste heat from fractionation
LP steam
Water reuse >98 w/w%, 0% TDS
Wastewater 0.7–3% ‘fatty matter’
<2 w/w% 30% ‘fatty matter’
Wastewater
Figure 7 Using a holistic design approach to maximise energy efficiency while minimising the process water consumption and environmental footprint of the HVO complex
petroleum refineries, where many facilities are already on-stream or under construction. The quest for the future is to maximise the use of wastes and non-edible oils as renewable feedstocks and to design the pretreatment facilities for maximum flexibility to handle such feedstocks. At the same time, there is increased focus on saving energy, reducing emissions and molecule management. Optimising the product fractionator for maximal performance – using high-efficiency WPHEs whose capabilities exceed those of conventional heat exchangers – is fully in line with these goals. Alfa Laval can be instrumental in both regards. The company, which has been designing fat and oil treatment plants for more than 50 years, has delivered more than 1,000 plants to the food and biofuel markets and is also the leading supplier of pretreatment plants for HVO processing. It has also supplied close to 3,000 WPHEs (Compabloc) for different refinery processes since the mid-1990s. When the fractionation section is optimised using WPHEs as feed/bottoms interchangers, overhead vapour condensers, steam generators and product coolers, it is possible to: • Increase energy efficiency • Increase the recovery of high-value molecules • Maximise waste heat recovery • Minimise the cooling water requirement • Reduce the cost of investment in expensive
process equipment such as reboilers, air coolers, piping, and pumps. It is even more important, however, to take a holistic approach to the investment in a new HVO complex. The pretreatment, wastewater, and HVO processes should be considered together rather than optimised independently: • Waste heat from the HVO processes can be utilised to generate low-pressure steam • The generated steam can be used to evaporate the wastewater from all processes • Evaporation of the wastewater will minimise the final waste stream to be treated, making it possible to recycle and reuse more than 98% of the process water in the pretreatment plant. Such interconnections are an opportunity well worth evaluating, as they can maximise the profitability of the HVO complex (see Figure 7 ). Alfa Laval can help select the best pretreatment scheme for HVO feedstock. It has expertise in designing wastewater evaporation systems and its WPHEs can boost HVO processing profitability.
Jay Jeong jay.jeong@alfalaval.com
Bent Sarup bent.sarup@alfalaval.com Eva Andersson evae.andersson@alfalaval.com
www.decarbonisationtechnology.com
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