ENERGY SAVING IN FROZEN FOOD PROCESSING

Objectif

To achieve significant energy savings in the processing of frozen vegetables by the construction of a cost effective energy plant. Annual energy savings of 34,500 TOE were to be achieved with a payback of 5.9 years. Cost estimates are DF 83,000 for instrumentation and DF 4.379 million for construction.
As already mentioned in 1986 the project only succeeded partially. The project really consists of 2 different items being :
a1. Improved energy effective blanching methods for leaf products such as spinach etc.
a2. Improved energy effective blanching methods for loose frozen products such as beans, peas etc.
b. A cogeneration plant consisting of 2 (in final phase 4) gasmotor units of 522 kW each.
The reclaimed heat produced by the gasmotors was stored in vertical accumulators with the intention to use this reclaimed heat for the processes mentioned under a.
From the report in 1986 it could be found that part a. of the project gave quite favourable results whereas part b. was unsuccessful at that time due to several technical failures of the gasmotor system.
Due to the energy price reduction in 1987 part b. of the project got more and more unflavourable in view of the high maintenance cost.
In 1989 a major break down occured in the gasmotor plant resulting in crucial damage of the2 gasmotors and the combined gearbox.
Reconstruction of the plant would have costed more than Dfl. 600.000 which, in view of the poor results with that plant, was an amount of money which could not be spent.
Therefore it was decided to remove the gasmotor plant which means that since 1990 that part of the plant is no longer in use.
Part a. of the plant however is still operating quite favourably. The number of hydrostatic blanchers for leaf products has even been increased to 4 instead of the 2 units which were operational when the project was started.
To replace the gasmotors, one of the existing steam boilers has been reconstructed as hot boiler in order to serve the belt blanchers entirely and the hydrostatic blanchers partially.
During low seasons 1992/1993 it is intended to upgrade the existing boiler plant and to equip all boilers with economizers and stack gas condensers.
This was not applicable in the period when the gasmotor plant was operational since at that time the boiler plant was only used as standby facility.
Groko BV. processes annually +/- 31 million kg. of frozen vegetables. Energy requirements are high, with natural gas consumption of 4.8 m. Nm3 and 12.6 m. kWh of electricity.
Steam consumption ranges from +/- 400-1,000 kg/t. of end product.
To meet the objective of this project a complete new energy plant was to be constructed.
It should have consisted of 4 Caterpillar (G 398TA) gas motors of 522 kW each, to be equipped in tandem on one shaft end with an angle gear box (However, only half of this capacity was actually installed). This is connected at one end with a high or low pressure screw compressor; at the other end with a 1,050 kW generator.
The gas motors produce waste heat at several levels. Waste heat of the jacket cooling and of the first stage exhaust gas cooling is stored as pressurized water at 135 deg.C. Second stage exhaust gas, cooling from 150 to 40 deg.C will be used to produce warm water at 30 to 70 deg.C. This significantly increases the system's efficiency andwaste heat from the oil coolers is used in the low grade warm water circuit.
The warm water is used for space heating in offices, packing departments etc.
Low grade waste heat additionally heats two water tanks for the automatic defrost of freezing equipment and, during summer, a swimming pool. Radiation heat from the motors provide space heating in production areas via a controlled ventilating system.
To minimize heat loss new belt blanchers were installed consisting of a transport belt and water basin at entry and outlet. Blanching takes place under a closed hood above water to prevent steam escape. Pressure under the hood is maintained at a level corresponding to 100.5 deg.C a process achieving 70% efficiency. Other improvements (eg. using accumulators) in the overall process, were made to enhance energy savings.

Programme(s)

ENG-ENALT 1C - Programme (EEC) of financial support for projects to exploit alternative energy sources, 1979-1984

Thème(s)

1.6 - INDUSTRY

Appel à propositions

Data not available

Régime de financement

DEM - Demonstration contracts

Coordinateur

CAMPBELL NEDERLAND BV

Contribution de l’UE

Aucune donnée

Adresse

GROKO DIVISION INDUSTRIEWEG 9-11
4880 AA ZUNDERT
Pays-Bas

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