298 94 307/02 Untersuchungen zum Stand der Umsetzung des ...
298 94 307/02 Untersuchungen zum Stand der Umsetzung des ... 298 94 307/02 Untersuchungen zum Stand der Umsetzung des ...
D Neutralisation 37 X X 41 X 43 X Teil 3 Seite 6-17 46 X X The washed limed ossein, still contains lime and has a high pH, in the centre of the par- ticles. It is treated with dilute acid to neutralise and remove the lime, and change the pH to pH 4.5 – 7. The batch of ossein is submerged in at least as much water as the original weight of the bone chips from which the ossein was made. The ossein ids stirred and the acid is added. The pH is measured continuously and can be used to control the flow of acid. When the pH remains constant for several hours within the desired pH range with- out acid being added, the ossein is considered to be neutralised. The acid water is then run off and the ossein is washed with at least five times its own weight of fresh water, whilst remaining submerged. The neutralisation can be done in one or more stirred tanks, in the extraction vessel. The installation is usually made of stainless steel or plastic coated steel. E Extraction The gelatine is extracted from the neutralised ossein with hot water. This involves about 5 steps, at progressively higher temperatures, usually with no more than 10 ºC difference between steps and typically ranging between 50 - 60 ºC and 100 ºC. The gelatine con- centration of the extract is normally 3 - 8 %. The water can be added cold and heated, or already heated. The ossein in the extrac- tors may be stirred carefully in the warm water or the water may be circulated over the ossein bed. This is continued until a concentration of about 5 %, is reached. The extract is then drained and the process is repeated, usually at a higher temperature. When drained the extract usually passes a sieve or a mesh to prevent large particles getting into the pipework. The final extraction is stopped when, while extracting at 100 ºC the concen- tration does not reach 3 %, or when no ossein is left. The amount of water required is at least the amount needed to submerge the ossein, plus the amount to fill pipes, pumps and heat exchangers. For ossein coming from 50 tonnes of bone chips the amount of gelatine in each extract is between 1500 kg and 4000 kg. The installations are normally made of stainless steel. F Filtration The extract is filtered to remove any insoluble particles. The filtration can be done in one or more steps. The filter medium is generally diatomaceous earth or cellulose, although cotton may also be used. If diatomaceous earth is used, a filter aid, usually composed of the same kind of diatomaceous earth as filter, is added to the gelatine solution, to prevent blocking by continuously building up the filter layer. When using cellulose, pulp pads of about 5 cm thickness can be used. Often the filtration is done in two steps, the diatoma-
Teil 3 Seite 6-18 ceous earth filter being followed by a filter that uses commercially available cellulose filter pads, which are about 1 cm thick. The extract may pass a cloth filter bag first, to remove residual coarse particles. During filtration the temperature of the solution is kept at 55 - 60 ºC. The filtration equipment usually of the type used in several branches of the food industry and is readily available. The diatomaceous earth filtration can be either pressure vacuum operated. For pressure operated filtration the filter bed is in a closed vessel which is pressurised. When the maximum pressure is reached, the filter meshes are automatically cleaned and covered with new filter aid. For vacuum filtration the filter is usually a rotating drum filter with the filter layer on the outside of the drum. The extract is sucked into the inside of the drum. With this kind of filter, the filter aid and the layer is automatically scraped off, so the filter has continuously a fresh surface. G Ion exchange The filtered extract is passed through an ion exchange resin to remove all dissolved salts from the solution. With limed bone gelatine the solution normally first passes the cation column and then the anion column. Most installations consist of two cation columns and two anion columns of which one of each is in use, while the other two are either regener- ating, or are on standby. Modern installations have an automatic control system that changes the flow to the standby column as soon as the column in use reduces in effec- tiveness and it starts the automatic regeneration procedure for the exhausted column. Older installations are less automated. The cation and anion exchangers are regenerated with approximately 5 % hydrochloric acid and approximately 5 % sodium hydroxide and both are rinsed using de-ionised water. An example columns size is 157 cm diameter and 175 cm height. The flow through such a column is about 7000 litres/hour. During the ion- exchange the temperature of the solution is generally kept at 55 - 60 ºC. The installations are made of synthetic material or of plastic coated steel. H Concentration After the solution that comes from the ion-exchangers the next step is to concentrate it in multiple-effect vacuum evaporators, this facilitates the removal of water at relatively low temperatures. Different designs of evaporators can be used for this. The vapour ex- tracted from the first effect is used to heat the second and that from the second is used to heat the third. The heating and cooling is undertaken very quickly so that the product is not damaged. At this stage in the process the solution is now about 20 - 30 % gelatine. The equipment is made of stainless steel. I Sterilisation The concentrated gelatine solution is sterilised either by direct steam injection such that the temperature is raised to 138 - 140 ºC or by operating the final effect at a temperature of about 120 - 140 °C. If direct steam injection is used, the solution is kept at this tem- perature during at least 4 seconds and a pressure of at least 4 bar is maintained. The temperature of the gelatine is measured and monitored continuously. The sterilising equipment is made of stainless steel.
- Seite 253 und 254: Teil 3 Seite 4-26 4.5.2.1 Ammoniaca
- Seite 255 und 256: Teil 3 Seite 4-28 Brögbern animal
- Seite 257 und 258: Teil 3 Seite 4-30 The decision depe
- Seite 259 und 260: Teil 3 Seite 4-32 closed area can b
- Seite 261 und 262: Teil 3 Seite 4-34 coincides with th
- Seite 263 und 264: Teil 3 Seite 4-36 At a slaughterhou
- Seite 265 und 266: Age of sludge (tTS) Is this of spec
- Seite 267 und 268: Example plants Teil 3 Seite 4-40 Co
- Seite 269 und 270: BSB5 - load Bd (BSB ) NH4 -N - load
- Seite 271 und 272: Fe Fl Fe Fl P D MB Teil 3 Seite 4-4
- Seite 273 und 274: Teil 3 Seite 4-46 Parameters Unit M
- Seite 275 und 276: Teil 3 Seite 4-48 To optimise the m
- Seite 277 und 278: Driving force for implementation Ex
- Seite 279 und 280: Teil 3 Seite 4-52 Table 4-15 Dimens
- Seite 281 und 282: Teil 3 Seite 4-54 liquid fertiliser
- Seite 283 und 284: - No cross media effects Teil 3 Sei
- Seite 285 und 286: Teil 3 Seite 4-58 3. Filtermaterial
- Seite 287 und 288: Decomposition level Measure- Teil 3
- Seite 289 und 290: Teil 3 Seite 6-2 FAT/ HEAT TRANSFER
- Seite 291 und 292: Teil 3 Seite 6-4 Clarification plan
- Seite 293 und 294: Teil 3 Seite 6-6 ENERGY FAT/ HEAT C
- Seite 295 und 296: Teil 3 Seite 6-8 ENERGY/ STEAM INPU
- Seite 297 und 298: Teil 3 Seite 6-10 water if necessar
- Seite 299 und 300: Teil 3 Seite 6-12 - In- vessel comp
- Seite 301 und 302: Teil 3 Seite 6-14 For 1000 kg of de
- Seite 303: Teil 3 Seite 6-16 Liming is usually
- Seite 307 und 308: See description under 1 Limed bone
- Seite 309 und 310: H Concentration See description und
- Seite 311 und 312: Teil 3 Seite 6-24 The excess acid i
- Seite 313 und 314: Teil 3 Seite 7-1 7 CURRENT CONSUMPT
- Seite 315 und 316: 7.1.1 Rendering 7.1.1.1 Water Teil
- Seite 317 und 318: Teil 3 Seite 7-5 - Cleaning wastewa
- Seite 319 und 320: Teil 3 Seite 7-7 Table 7-5 shows th
- Seite 321 und 322: 7.1.2 Fat melting 7.1.3 Fish meal a
- Seite 323 und 324: Teil 3 Seite 8-1 8 TECHNIQUES TO CO
- Seite 325 und 326: Reference literature Teil 3 Seite 8
- Seite 327 und 328: Teil 3 Seite 8-5 Corporate clarific
- Seite 329 und 330: Economics Driving force for impleme
- Seite 331 und 332: 8.1.9 Rubishes Teil 3 Seite 8-9 8.1
- Seite 333 und 334: Oberding animal carcass disposal pl
- Seite 335 und 336: Operational data Applicability Econ
- Seite 337 und 338: Teil 3 Seite 8-15 Corporate clarifi
- Seite 339 und 340: Driving force for implementation Ex
- Seite 341 und 342: Continuous sterilisation Teil 3 Sei
- Seite 343 und 344: Teil 3 Seite 8-21 through a system
- Seite 345 und 346: Cross media effects Operational dat
- Seite 347 und 348: Teil 3 Seite 8-25 The energy requir
- Seite 349 und 350: Teil 3 Seite 8-27 For the wastewate
- Seite 351 und 352: Teil 3 Seite 8-29 Corporate clarifi
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D Neutralisation<br />
37 X X<br />
41 X<br />
43 X<br />
Teil 3 Seite 6-17<br />
46 X X<br />
The washed limed ossein, still contains lime and has a high pH, in the centre of the par-<br />
ticles. It is treated with dilute acid to neutralise and remove the lime, and change the pH<br />
to pH 4.5 – 7. The batch of ossein is submerged in at least as much water as the original<br />
weight of the bone chips from which the ossein was made. The ossein ids stirred and the<br />
acid is added. The pH is measured continuously and can be used to control the flow of<br />
acid. When the pH remains constant for several hours within the <strong>des</strong>ired pH range with-<br />
out acid being added, the ossein is consi<strong>der</strong>ed to be neutralised. The acid water is then<br />
run off and the ossein is washed with at least five times its own weight of fresh water,<br />
whilst remaining submerged. The neutralisation can be done in one or more stirred tanks,<br />
in the extraction vessel. The installation is usually made of stainless steel or plastic<br />
coated steel.<br />
E Extraction<br />
The gelatine is extracted from the neutralised ossein with hot water. This involves about<br />
5 steps, at progressively higher temperatures, usually with no more than 10 ºC difference<br />
between steps and typically ranging between 50 - 60 ºC and 100 ºC. The gelatine con-<br />
centration of the extract is normally 3 - 8 %.<br />
The water can be added cold and heated, or already heated. The ossein in the extrac-<br />
tors may be stirred carefully in the warm water or the water may be circulated over the<br />
ossein bed. This is continued until a concentration of about 5 %, is reached. The extract<br />
is then drained and the process is repeated, usually at a higher temperature. When<br />
drained the extract usually passes a sieve or a mesh to prevent large particles getting into<br />
the pipework. The final extraction is stopped when, while extracting at 100 ºC the concen-<br />
tration does not reach 3 %, or when no ossein is left. The amount of water required is at<br />
least the amount needed to submerge the ossein, plus the amount to fill pipes, pumps and<br />
heat exchangers. For ossein coming from 50 tonnes of bone chips the amount of gelatine<br />
in each extract is between 1500 kg and 4000 kg.<br />
The installations are normally made of stainless steel.<br />
F Filtration<br />
The extract is filtered to remove any insoluble particles. The filtration can be done in one<br />
or more steps. The filter medium is generally diatomaceous earth or cellulose, although<br />
cotton may also be used. If diatomaceous earth is used, a filter aid, usually composed of<br />
the same kind of diatomaceous earth as filter, is added to the gelatine solution, to prevent<br />
blocking by continuously building up the filter layer. When using cellulose, pulp pads of<br />
about 5 cm thickness can be used. Often the filtration is done in two steps, the diatoma-