在纺织漂白中可能产生水及节能技术.doc

POTENTIAL WATER AND ENERGY SAVINGS IN TEXTILE BLEACHING
在纺织漂白中可能产生的水和节能技术
by Bruce A. Evans
1.1There is a strong correlation between water and
energy use in textile bleaching，
水和能源消耗在纺织漂白有很强的相关性，
1.2.since a high proportion of the energy is used for heating wash water.
既然大部分的能源是用来加热清洗用水。
1.3Thus by reducing the water consumption of a bleach range
significant savings in energy can also be realized.
因此，通过降低用水量漂白的范围内 重要也可以实现能源的节省。

2.1A typical open-width bleach range consists of desize,
caustic, and peroxide bleach stages.
一个典型的平幅漂白包括退浆, 磨损、和过氧化氢漂白。
Each stage has a washing train, which requires a major water
feed, usually 50-75 gal./min., which is counterflowed
through all the washers in that stage.
每一阶段都有一洗的火车, 这主要需要一个给水的过程，通常是50-75 加仑/分钟，此阶段中水流在所有的洗净器中都是逆向的。

(Data used in this discussion are based on 60 gal./min. at the desize washers and 50 gal/min. each at the caustic and
bleach washers.)
本次讨论使用的数据在退浆洗净器中按照60 加仑/分钟，在丝光及漂白洗净器中按照50 加仑/分钟.
Water temperatures vary but are almost always at least 180°F.
水温是变化的，但几乎总在至少180°F
The water and energy use for such a bleach range are shown in Table 1.
这一漂白过程中使用的水和能源见表—1.
3.1 Of the total 16,450 lb. steam/hour required to operate the bleach range, 10,350 are used by the washing systems--this figure includes 8100 lb. steam/hr. needed to achieve 180oF and 2250 lb.steam/hr. to compensate for heat losses.
进行漂白过程每小时共需要16,450lb.蒸汽，其中10,350 用于清洗设备中—这一数字中，每小时8100 lb.蒸汽用于使温度达到180°F，每小时有2250 lb.蒸汽用于补偿热消耗。
Energy losses are mainly evaporative and could be reduced
substantially if enclosed washers were used.
能耗主要因蒸发引起，如果使用封闭式的洗净器基本上可以避免。
There is an obvious opportunity for saving both water and
energy by reducing water flows and temperatures on the bleach range. We will discuss the following options:
在漂白阶段，通过减小水流和降低温度可以为节水节能提供一个明显的机会。

1. Reduce water temperature
1.降低水温。
2. Reduce water flow rates
2.降低水流速度。
3. Reduce the number of water feeds
3.减少给水量。
a. by counterflowing between stages
a.在不同阶段逆流
b. by reducing the number of stages
b.缩减阶段数
The estimated savings available by making these
changes are summarized in Table 2.
通过这些变化估计可节省的各项总结在表2中。
REDUCE WATER TEMPERATURE
降低水温
The bleach washers remove a relatively small share of the impurities in the fabric, and reductions in water temperature are best considered there.
漂白净洗器除去了织物中相对来说比例较小的杂质，而且减少水的温度是最好的考虑。
As shown inTable 2, a decrease of I0oF from 180o to 170° at the bleach washers would decrease energy requirements
by 250 lb./steam/hour; it would not reduce the water
requirement at all.
如表2所示，在漂白净洗器中从180到170减少的10 每小时可减少250 lb.蒸汽需要的能源，然而它丝毫不会减少需水量。
For most bleach ranges this is a relatively safe change.
对于大部分的漂白过程来说这是一种相对较安全的改变。
In fact many mills run 150°-160°F water in the bleach washers.
实际上许多工厂里净洗器中水温在150-160 °F
REDUCE WATER FLOW RATES
降低水的流速
For the desize and caustic stages, temperature
reductions are not generally advisable because the
materials being removed (caustic, sizing polymers,
waxes) become more viscous or fall below their melt-
ing points in cooler water.
在退浆和丝光阶段，由于需要洗除物质（苛性钠，上浆的高聚物，蜡质）一般不推荐降低温度，这些物质在冷却水中会变粘稠或使得水温低于它们的熔点。
However, a reduction in the water flow rate of 5 gal./min. would save 300 gal./hour water and 300 lb. steam/hour energy.
然而，减少5 加仑/分钟的水流量会节省300加仑/分钟的水和300 lb.蒸汽/小时的能量。
This is attractive if it can be reliably determined that more
water than necessary is being used to remove the impurities.
如果它能够可靠地确定——即使用比必要的更多的水来去除杂质，
这是很有吸引力的
There are some potential problems,though, which make it difficult to lower flow rates:
尽管如此，仍有许多潜在的问题，这些问题使得难以降低流速。
+ Many mills do not control flow rates very well, and
would not recognize a reduction if it occurred.
许多工厂都无法很好地控制水的流动速率，而且如果真的减少了也不会意识到。
The bleach range operator often controls the flow valve at
his own whim.
从事漂白过程的操作者通常根据他自己一时的想法来控制流量阀
Flow rates should not be lowered until they are controlled and until fabric quality has been monitored with the present rates.
水的流动速率不会降低,直到它们被控制，直到织物质量监控到以现在的流速进行。
+ No automatic monitors are available to measure
the concentration of impurities in the wash water or
on the fabric.
现在缺乏可以在清洗的水中和织物上自动测量杂质浓度的监控器。
Data on the effects of changes must be gathered by painstaking laboratory work.
有关这些变化产生的影响的数据必须由辛勤的实验室工作来获得。
+ In the absence of other controls, the water flow is
set to be sufficient for the most difficult fabrics processed.
在没有其他的控制下，水的流速设定为能够用来处理最难以处理的织物。
It is generally changed for more easily washed
fabrics. (A control was recently introduced which
allows automatic variation of wash water flow with the
lb./hour of fabric produced-this assumes that the
difficulty of washing is proportional to fabric weight,
which is reasonable for most types of fabric.)
一般而言,对于较易洗织物流速容易改变——最近引进了一种控制方法即假定织物的清洗难度与织物的重量成正比，该种控制方法允许清洗的水的流动随由此产生lb./小时的织物自动变化。
One valid way of reducing water flow is to use more
efficient washers.
一种更有效的减小水流的方法是使用更高效的洗净器。
Horizontal washers use about one-third to one-quarter as much water as vertical washers for the same washing job. Water and energy use is reduced accordingly.
对于同样的清洗工作量，水平洗净器大约使用竖直式洗净器1/4-1/3的水。水和能源的使用同时减少。
REDUCE THE NUMBER OF WATER FEEDS
减少给水装置的数量
A. Counterflow Between Stages
A.在不同阶段逆流
As stated earlier the standard open-width continuous bleach range has three separate water feeds.
如前所述，标准平幅连续漂白过程有三个独立的喂水装置。
Counterflowing water from the bleach washers to the
caustic washers could elimnate 3000 gal./hour water
feed and could save 2600 lb. steam/hour.
从漂白清洗器流向丝光清洗器的逆流水可以抵消3000加仑/小时的给水量而且可以节省2600 lb.蒸汽/小时.
A masse-nergy balance of a typical bleach range has shown
that the total impurities in the bleach wash water as it is discharged are about 0.03 lb./gallon, or 0.34% by weight.
典型的漂白流程中的质能守恒表明在漂白清洗水中排出的杂质约占总量的0.03 lb. /加仑，或在重量上占0.34%。
It is clean enough for re-use in the desize or caustic stage for most mills, and many of them have recently begun to take advantage of it.
对于大部分工厂，在退浆或丝光阶段这些水清洁得可以再利用，很多工厂已经开始利用它。

It is possible to recycle the same water through all three stages, but it is rarely done.
通过这三个完整阶段是可能回收利用同样的水的，但很少有企业这样做。
Wash water used in both the bleach and caustic stages will contain about 1.3% impurities by weight, and its re-use in the desize stage might lower washing efficiency too much.
在漂白和丝光过程中使用的清洗水约含1.3%的杂质（按重量），它在退浆阶段 再利用会大大地降低清洗效率。
There is also the possibility of coagulation of impurities
due to cooling during the counterflowing.
由于逆流过程中的冷却也可能存在杂质凝固。
In spite of the high incentive (6000 gal./hour and 5300 lb.
steam/hour) full counterflow is practiced on very few ranges.
尽管有高的incentive(6000加仑/小时和5300 lb蒸汽/小时)在各个阶段几乎不采用完全逆流。
B. Reduce the number of stages
B.减少流程数量
Elimination of a bleach range stage means elimination
of a saturator, steamer and water feed, which saves 3100 gal./hour and 3700 lb. steam/hour.
在漂白流程中的节省就意味着节省了饱和剂，蒸汽和供给水，这将每小时节省3100加仑的水和3700 lb蒸汽。
There are three options:
这里有3种方法可供选择：
+ Combining desize and caustic functions.
把退浆和丝光整理合为一步。
This option is especially attractive for polyester/cotton blends,
because polyvinyl alcohol is often used as size and because caustic levels are kept low to protect the polyester.
这个方法对于聚酯/棉混纺织物很有吸引力因为聚酯/棉混纺织物常常使用聚乙烯醇做浆料而且由于保护聚酯丝光程度一直很低。
Since polyvinyl alcohol is removed by hot water washing, the system is really a “NO-DESIZE”one.
由于聚乙烯醇在热水清洗中就被除去，这套系统事实上是一个“无浆”系统。
A small addition of hydrogen peroxide, stabilized with Epsom Salt, can assist in removal of the polyvinyl alcohol and other minor sizing polymers which may be present.
由于加入七水合硫酸镁而稳定的少量的过氧化氢可以有助于除去可能存在的聚乙烯醇和其他少量的上浆聚合物。
+ Combining caustic and bleach functions.
将丝光和漂白整理合二为一。
If the caustic stage is eliminated the result is a desize-bleach
system; DuPont introduced this concept during the 1950’s as the Solo-Matic process.
如果没有了丝光过程那么结果就是一个退浆-漂白体系；1950年
DuPont把它作为一个独立的温控处理概念引入。
The most popular configuration is rope desizing in bins followed by a single J-Box to perform the functions of both caustic and bleach stages.
最受欢迎的配置为绳退浆在布箱里进行的绳退浆，它伴随着一个单一的J形箱来进行丝光和漂白阶段的两种整理。
It is intended primarily for relatively light-weight open-weave fabrics including soft filled sheeting, polyester/cotton shirtings, and prepares for printing and non-critical dyeing.
J形箱最初是为质量相对较轻的open-weave织物 包括柔软的filled sheeting，聚酯/棉衬衫而设计，是为进行印花和粗染做准备。
Its major limitations are development of absorbency and removal of motes, both of which require a strong caustic
treatment.
它主要的局限是需要增加吸湿度和去除颗粒，这两者都要求较强的丝光处理。

The bleach bath in a desize-bleach system uses a high alkali content and requires sodium silicate buffering to pH 10.8-11.0; 1.25-1.50 hours of steaming time are needed to produce good results.
在退浆-漂白系统里漂白水浴使用高浓度的碱，需要pH值在10.8-11.0 的硅酸钠缓冲液,需要1.25-1.50小时的蒸煮时间来获得良好的效果。
Because of the long steaming time there is no comparable open width process available.
由于长时间的蒸煮，它与开幅加工没有可比性。
+ Single Stage Bleaching. The prospect of eliminating
two stages, including saturators, steamers, and washers has resulted in widespread interest in singlestage bleaching.
+仅有漂白这一阶段。
Present rope applications include knit goods, bedsheets, terry cloth, and light weight polyester/cotton shirtings.

There are very few open-width single-stage bleach ranges because of the limited steaming times available; a few plants run corduroy and other fabrics for non-critical dyeing use on a single-stage ranges, but results are often marginal.

The conveyor steamer,with 15-20 minutes steaming time, is of greatest interest for open-width single-stage bleaching, although few such applications are presently running.

PRE-WASHING
预洗
In any single-stage system and in many other abbreviated bleach configurations it will be beneficial to use a prewashing train with recycled water from the bleach stage--this might be called a l-l/2 stage range.

Prewashing can remove significant quantities of sizing and natural impurities which would otherwise have to be removed by the final washers, and which might affect the stability of the bleach bath.

Since prewashing with recycled water does not increase water consumption and has very little impact on energy use, it is always recommended.
由于用循环水预洗不会增加水的消耗，而且对能源的使用几乎没有影响
CONCLUSION
结语
There are significant potential savings in both water and energy available by carefully selecting the optimum bleach range configuration for the types of fabrics being processed.

In some textile areas the cost of water including waste treatment exceeds $1.00/1000 gallons.

Energy as oil-fired steam costs about $7.00/1000 lb. delivered to the bleach range.

At these costs escalate, the potential savings will grow proportionately.

As an example, using the above costs, the process change “Counterflow from Bleach Washers to Caustic Washers” (Table 2) would save about $20,000/year water cost and $ll0,000/year energy cost, for a total saving of $130,000/year.

Realization of such savings requires careful optimization
of the bleach range configuration for the types of fabrics being processed, constant control of water and energy use, and careful attention to equipment maintenance to avoid waste.

Textile finishing plants generally recognize the opportunity and necessity of saving water and energy and are making rapid progress in that endeavor.

分割线 表解释
aE. I. DuPont deNemours & Co., Inc., Chemicals and
Pigments Department, Chestnut Run, Wilmington, DL 79898