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From the conference held by Mario Gozzi (CFT) during the World Tomato Processing Congress (Budapest, 9-12 June 2024, “Technology and innovation in the tomato processing industry” session).
Here is the second part: the presentation addressing how the technology truly impacts countries very differently depending on the specific costs of energy of the country. We have developed a matrix correlating the working costs savings from technology with the geographic regions. For doing that we considered four tomato processing countries: California, China, Italy and Chile. We picked four electrification technologies with growing electrification and then a fifth scenario which is cogeneration, and we monitored the working costs in this matrix.
In addition to the information presented during the Congress by Antonio Casana concerning the legislative frameworks for taxing CO2 emissions (“The economic, social and environmental sustainability of the European tomato supply chain”, Antonio Casana (Tomato Europe), see also related articles below), the graph below shows how much the European Emission Trading System (ETS) and the California Cap and Trade (CaT) rose their values for the ton of CO2 starting 2020. Undoubtedly, China and Chile will follow – it might take a little bit longer – but they will follow, and this CO2 price increase trend is not likely to stop anytime soon.
As we do electrify the factory, the regions matter. This graph shows that, consuming the KWh of electrical energy in China, where only 31% of the energy is renewable, will generate 0.48 kg of CO2 per KWh and only 0.23 kg of CO2 per KWh in Chile where the percentage of renewable energy is much higher. The conversion factor is very strongly regional-dependent and is affected by the energetic mix of the region.
That is the matrix we have built, for the four scenarios. The first one is the baseline, just a standard triple effect evaporator, nothing fancy. The second one is a smaller triple effect coupled with a low-density evaporator MVR up to 50% of the water removal, while the third is similar to the second but with an even smaller finishing effect and a mid-density evaporator capable of reaching 80% of the water removal . The fourth scenario is similar to the third, but we have another feature: the energy recovery from the multiple effect evaporator back into the Hot Break.
The last two columns show the results that can be achieved: sorry I couldn’t get to the “zero steam factory” as I promised in my title… but we are getting close! If you look at it, we went from 42 t/h of steam consumption which is the baseline, down to 15 ton/h (this is a 63% reduction) while the electric energy consumption, went up from 2.8 MWh to 4.9 MWh (data referred to a 2.400 t/day fresh fruit feed).
The last two columns show the results that can be achieved: sorry I couldn’t get to the “zero steam factory” as I promised in my title… but we are getting close! If you look at it, we went from 42 t/h of steam consumption which is the baseline, down to 15 ton/h (this is a 63% reduction) while the electric energy consumption, went up from 2.8 MWh to 4.9 MWh (data referred to a 2.400 t/day fresh fruit feed).
This chart shows what happens to the overall energy consumption (thermal plus electrical); we can see first of all that going from scenario 1 to scenario 4 (with increasing electrification), the overall energy consumption decreases by roughly 50%. Then we see inside the chart that electric proportion goes from 2.8 MWh (9% of the total) up to 32% of the total; but then the most important part – that some people sometimes don’t catch – is that the total area (total energy consumption) has shrunk by 50%! Here there is not only a shift from thermal to electrical, but most importantly, since we are not sending waste steam up to the atmosphere but rather re reutilizing it, we are reducing the energy consumption footprint by half. That are the results that can be achieved.
Here are some real energy costs, some real numbers; some of the customers were kind enough to share their values, and for Europe it was easy because the Eurostat database has all the European countries values.
Here we see that there is a tremendous difference in the energy costs; if you look at these numbers, the California steam cost is roughly 20 euros/ton, China is down at 11 euros/ton, Italy is 39 – very expensive thermal energy, and Chile is 31 euros/ton. Even more importantly, we think that what really matters are the numbers showing the ratio between the costs of electrical KWh to the cost of the thermal KWh.
Those ratios are fundamental to drive the technological choices. Also when you buy a heat pump, the first thing they will ask you is “what is the electrical to thermal ratio”. To electrify in a country like California for instance, it is challenging because the cost of electricity is so much higher than the cost of gas (over six times larger). Whereas, as a customer recently put it, “the MVR evaporator does shine in Chile and Italy”, because the ratio of electrical to thermal energy cost is only 2.7 or 3.
Here we have the final results: let’s start from California. From light blue to green, we go toward growing electrification, from scenario 1 to scenario 4 (remember: baseline, low density MVR at 50% w.r., mid density MVR at 80% w.r., mid density MVR plus heat recovery.
Here we have the final results: let’s start from California. From light blue to green, we go toward growing electrification, from scenario 1 to scenario 4 (remember: baseline, low density MVR at 50% w.r., mid density MVR at 80% w.r., mid density MVR plus heat recovery.
What happens when you do electrification in California? Of course thermal goes down, electrical goes up, carbon goes down and here is the total scenario: the first step is quite interesting, going from 130 euros of energy working cost per ton of tomato paste down to 107 euros; but after that, if we try to electrify further, the curve becomes flat and that is due to the fact that electric energy is so expensive; and this is also why some of the investment in California have been brought forward also thanks to State incentives. Electrification on its own as you see, generates a sort of a flatworking-cost curve. The first step toward a low-density MVR falling film evaporator is the one that seem to generate the biggest return.
In China things get better: we were able to get a 35% reduction on operational expenditure (-20 Euros per ton of paste). Chile and Italy are really "shining" because the electrical to thermal ratio is lower and electrification brings very, very remarkable advantages. If we look at the exact same charge but expressed in euros per season rather than in euros per ton, referring to a 2.400 t/day line, the gain in Italy is slightly bigger than 3 million Euros in saving per season.And this result can be seen in other countries as well.
So, definitely electrification is a good thing, but you must be aware it has different effects in different countries. Another option that has been utilized especially for countries with high electrical to thermal energy cost ratio, has been the cogeneration.
Cogeneration means that instead of having a plant far away producing our electricity, at very scarce efficiency and bringing it to the factory, we will feed directly the factory with gas and produce internally both electric and thermal demand.
Cogeneration means that instead of having a plant far away producing our electricity, at very scarce efficiency and bringing it to the factory, we will feed directly the factory with gas and produce internally both electric and thermal demand.
By doing so, a 32% efficiency can be gained as shown in the example.
This is an example of a typical cogeneration plant foreseeing a steam turbine, where some of the steam can be sent directly to the thermal utilization and some will come from the exhaust of the turbine. So we can have a 30 bar steam turbine and the exhaust at 6 bar will feed the thermal needs.
Again, we can put this data into a matrix: scenario 1 as the usual triple effect baseline, scenario 2 as cogeneration and, to give a matter of comparison, we take back scenario 4, the highest electrification from the previous charts.
What we do see is that the energy working cost is 130 euros per ton of paste that we have in California in the baseline triple effect, thanks to the electrification, comeso down quite remarkably and the effect of cogeneration is slightly better than the best electrification that we could do. On the contrary, in other countries, cogeneration does bring some results but not as good as the best electrification.
A final message is: "choose the best technology for energy reduction but keep in mind regionalization"; every project has to be checked, based on the cost of energy, on the ratio, and also based on local incentives.
To conclude our presentation, it is not only evaporation but there are some emerging technologies; one I want to mention is ohmic, for instance, because it is a growing emerging technology that substitutes condensing steam with electrical energy. It is already playing a role in electrification substituting fossil fuels with electricity providing homogenous heating and minimizes product losses because it is very compact. It has high modularity because it comes in 60 KW modules that can be expanded along the way and it can achieve very, very precise temperature values.
It reduces fouling and finally, if we look at it with the eye of tomato processing, in a flash cooler, it would eliminate completely the dilution that a typical steam injection would cause in a typical flash cooler. That is another source of savings.
It has of course a couple of limitations as well, which are the fact that electricity is more expensive than gas, 2 to 6 folds as we learned from the previous slides. The generators are currently limited to 60 KW and could provide CO2 emission reduction depending on the region.
Hopefully the above will serve as a useful guideline for energy efficiency projects in your own region covering all the aspects involved.
Some complementary data
The era of zero-steam tomato plants, Mario Gozzi (CFT)
The economic, social and environmental sustainability of the European tomato supply chain, Antonio Casana (Tomato Europe)
Sources: CFT, World Processing Tomato Congress (2024, Budapest)
The era of zero-steam tomato plants, Mario Gozzi (CFT)
The economic, social and environmental sustainability of the European tomato supply chain, Antonio Casana (Tomato Europe)
Sources: CFT, World Processing Tomato Congress (2024, Budapest)
