Information about cake

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1. GENERAL DESCRIPTION:

1.1 General Flowsheet of cake production

Cake production.JPG

Figure 1: Production of cakes. Literature: Heiss, R. [Hrsg.]: Lebensmitteltechnologie


1.2 Description of techniques, methods and equipment

(BAT for Food, Drink and Milk Industries, June 2005)

Cake is a form of bread or bread-like food. In its modern forms, it is typically a sweet baked dessert. In its oldest forms, cakes were normally fried breads or cheesecakes, and normally had a disk shapeThe main ingredients are wheat flour, fat, eggs, sugar, milk powder, water flavouring and raising agents.

Cakes are generally made by using two different methods:


  • Sugar batter method
    fat and sugar are creamed together, eggs are added in stages


  • Flour batter method
    fat and flour are blended together. Eggs and sugar are whisked are whisked together and the mixture is blended into the flour-fat- mix in stages. Then the liquid are added in small amounts.


In continuous mixing systems the ingredients are given a preliminary mix and are then fed in a continuous even stream. But more often used is “all in” high speed mixing. All ingredients (except fruit) are added, and then fruit is added in short bursts.

The batter is put into oil- sprayed trays. After baking the cakes are removed from the tins and are cooled.


1.3 Temperature ranges and other parameters


Bakery Cake Temperature.png

Table 1: Temperature range of processes involved , Literature: UNIDO Technology Manual : Small scale cereal milling and bakery products.


1.4 Benchmark data



Bakery Cake Energy.png

Table 2: Energy Consumption in BTU per pound of product, Literature: Energy efficiency improvement and cost saving opportunitieas for the bakign industry.Eric Masanet,Peter Therkelsen and Ernst Worrell.

2. CHANGES IN PROCESSES:

2.1 Preheating in Baking Oven

2.1.1Changes in Energy Supply for unique Technology
2.1.1.1 Existing Heat/Cool Technology

The oven is preheated with hot water

2.1.1.2Changes in Distribution of the Heat/Cool System

Water is replaced by Air

2.1.1.3 Optimisation of the Heat/Cool System

This preheating can be performed by The Air-cooled heat exchanger which is a device for rejecting heat from a fluid or gas directly to ambient air. When cooling both fluids and gases, there are two sources readily available,with a relatively low cost, to transfer heat to air and water.The obvious advantage of an air cooler is that it does not require water, which means that equipment requiring cooling need not be near a supply of cooling water. In addition, the problems associated with treatment and disposal of water have become more costly with government regulations and environmental concerns. The air-cooled heat exchanger provides a means of transferring the heat from the fluid or gas into ambient air, without environmental concerns, or without great ongoing cost. [Source: Basics of Air cooled Heat Exchangers: Amercool Manufacturing Inc.]


2.2 Mist Fermentation

2.2.1Changes in Energy Supply for unique Technology
2.2.1.1 Existing Heat/Cool Technology

No use of Ultrasonic smokescreen generator

2.2.1.2Changes in Distribution of the Heat/Cool System
2.2.1.3 Optimisation of the Heat/Cool System

Small droplets are created through ultrasound that produces a mist for the fermentation process.This results in improved heat conductivity of the end product without drying out too much.Energy saving during baking (energy saving 17%) Ultrasonic smokescreen generator during fermentation allows a 17% energy saving. Investment costs are between 4000 to 12000 Euros [ Source: Energy-saving mist technology available on industrial scale By Oliver Nieburg]


2.3 Combination of microwaves with halogen lamp heating

2.3.1Changes in Energy Supply for unique Technology
2.3.1.1 Existing Heat/Cool Technology

Coventional Baking Oven

2.3.1.2Changes in Distribution of the Heat/Cool System
2.3.1.3 Optimisation of the Heat/Cool System

The ‘halogen lamp- microwave combination oven combines the browning and crisping of halogen lamp heating with the time saving advantages of microwave heating. This oven is called as Advantium oven and is produced by GE. Halogen lamp microwave combination baking has been used in bread baking and It has reduced the conventional baking time of breads by about 75 per cent ( Keskin et al., 2004) Specific volume and colour values of bread baked in a halogen lamp microwave combination oven were comparable with that of conventionally baked breads but weight loss and firmness values of those breads were higher as seen in the Table. Breads baked in the microwave oven had the highest specific volume. This can be explained by significant internal pressure which might result in a puffing effect and high volume. The increase in halogen lamp power reduced specific volume and increased weight loss, firmness and colour values of breads in halogen lamp microwave, combination baking. [Source: Emerging Technologies for Food Processing By Da-Wen Sun]


2.4 Proofing in Bakeries

2.4.1Changes in Energy Supply for unique Technology
2.4.1.1 Existing Heat/Cool Technology

The temperature of the proofer oven is generally about 40 degrees Celsius with a relative humidity of 70-80 percent. Heat required for this part of bread baking is typically produced using steam from gas fired boilers. This is a high energy consuming and expensive way of heating the proofing oven.Loaves of bread are baked in the main oven at temperatures of 300 to 400 degrees Celsius. Excess oven exhaust gases are released into the atmosphere as wasted heat.

2.4.1.2Changes in Distribution of the Heat/Cool System

Heat pipes are devices which provide effective heat transfer. They operate by evacuating air and replacing it in part with a fluid such as water. When hot exhaust gases from the baking oven come in contact with the pipe containing the liquid, the liquid first boils and then condenses in cooler parts of the pipe, thereby transferring energy as latent heat. The heat extracted is fed directly into the proofer oven, conserving energy while providing air free of contamination.

2.4.1.3 Optimisation of the Heat/Cool System

The temperature range of the baking oven's flue gas ranges from 300 to 350 degrees Celsius. The waste heat available ranges from 70-80kW and the proofing oven requires energy between 20-45kW. With an air velocity for the system of 1.5 metres per second and an heat exchanger effectiveness of around 65 percent, the waste heat recovery system was able to supply all the heat needed by the proofing oven, thus eliminating the need for any natural gas heating.


Baking Proofing.png

Figure 2: Proofing with Heat Exchanger in Bakeries

The heat exchanger was manufactured locally from steel pipes charged with distilled water. The RMIT research team supervised the manufacturing process to ensure that the equipment would withstand the high temperature and corrosive environment of the baking oven's exhaust gases. Based on annual saving of 500GJ per year for one shift, cost of natural gas at $4 per GJ, and boiler efficiency of 70 percent, the pay back period is less than 3.5 years. For a three shift operation, the pay back period is reduced to 1.5 years.


2.5 System for building heating and domestic water heating with the Waste heat from flue gas, baking steam and refrigeration system (With controller, boiler as a heat reserve

2.5.1Changes in Energy Supply for unique Technology
2.5.1.1 Existing Heat/Cool Technology
Steam Condensor of the series SK for all oven types with separate steam exhauster.
2.5.1.2Changes in Distribution of the Heat/Cool System
2.5.1.3 Optimisation of the Heat/Cool System
NET steam condensers are specially designed for heat recovery from the baking fumes developed. With these devices, the high heat of condensation of Water vapor are recovered in steam condensors.Their performance is higher, the higher the concentration of the water vapor and the lower the temperature of cooling water.However, they are not suitable for flue gas or exhaust air from fume hoods.The heat recovery steam from the baking supplies with NET smoke-condensators generally have a higher heat capacity than the Heat recovery from the exhaust of the oven burner.
The steam condensator of several juxtaposed ovens, in a common steam condenser is used. This is not only

cost-effective than separate steam condensers for each furnace, but leads also in a more uniform heat output, because in practice, the programs of the individual furnaces are shifted in time.For the connection of several ovens with the steam condensers to become three inputs supplied.Because of their extremely low flow resistance of the vapor can upon the opening the slider on the oven to escape freely. With a suitable selection of the correct type the baking result is not affected.

The recovered steam from the baking heat can be very good for heating be used by hot water and floor heating. For storage

this heat is a separate buffer memory or the lower portion of Layers of memory required. NET steam condensers are available in different sizes for different large plates supplied. For different installation situations all types supplied in two versions:

• execution left with inputs on the left side and
• Execution with right inputs on the right side
For furnaces with a lower vapor contents, there are special steam condensators. To this end, in individual cases, the time Course of temperature, vapor content and flow are measured. By the laws of nature-related regulation of the heat capacity is overheating NET steam condensators excluded.Removable lid allows for easy and fast cleaning with water. NET steam condensers have no moving parts. They are made of stainless steel with high nickel content (so-called. V4A steel) and have a long service life.
With this arrangement, the exhaust heat sources, steam and Chiller their temperature level corresponding to different levels of Buffer allocated and thereby optimally utilized.The upper portion of the memory at a higher temperature provides the Building heating system, the entire memory provides the heat for the heating of the Drinking water in a fresh water module. In this way, the heat well used at a lower temperature in the lower region of the memory.For increased demand in heat a boiler to reload the buffer memory is upper area provided.The regulation of the storage charge pump is a good stratification of heat in Storage and saves power for driving the pumps.

Figure 3: System for building heating and domestic water heating with the Waste heat from flue gas, baking steam and refrigeration system

(With controller, boiler as a heat reserve)



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