JPS60161325A - Apparatus for producing ammonium sulfate from coke oven gas - Google Patents

Abstract

PURPOSE:To reduce operating cost by utilizing cooling water effectively at high temp. which has been heat-exchanged in a primary cooler. CONSTITUTION:An apparatus for producing ammonium sulfate is constituted of a primary cooler 2 for cooling waste gas by exchanging heat between waste gas 3 discharged from a coke oven 1 and cooling water 4, an absorption tower 5 for absorbing ammonia from the cooled waste gas to generate mother liquor of ammonium sulfate 6, a first heater 9 for heating the generated mother liquor of ammonium sulfate 6, a first evaporating kettle 10 for concentrating the heated mother liquor 6, a second heater 11 for heating the concentrated mother liquor 6, and a second evaporating kettle 13 for concentrating the heated concentrated mother liquor 6 and generating crystalline ammonium sulfate. Heat exchangers 20, 21 for exchanging heat between a part of the mother liquor 6 generated in the absorption tower 5 and Li bromide 28 are installed by connecting in parallel to the first heater 9. The cooling water 4 at high temp. which has exchanged heat in the primary cooler 2 is utilized for a heat source for generating steam to be absorbed by the Li bromide 28.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an apparatus for producing ammonium sulfate from coke oven gas.

Structure of a conventional example and its problems FIG. 1 shows a conventional example. In the figure, (1) is a coke oven, (2) is a primary cooler that cools the exhaust gas (3) from the coke oven (1) by exchanging heat with cooling water (4), and (5) is a primary cooler. Ammonia is absorbed from the exhaust gas (3) cooled by (2) and ammonium sulfate mother liquor (6
) is an absorption tower that produces sulfuric acid (7) in advance. (8) is a tank that stores the ammonium sulfate mother liquor (6) produced in the absorption tower (5), (9) is a first heater that heats the ammonium sulfate mother liquor (6) drawn out from the tank (8), and O
Q is a first evaporator with a pressure of 160 to 200 to'rr for concentrating the ammonium sulfate mother liquor (6) heated in the first heater (9 tons); )
A part of the heating element is returned to the first heater (9) again. αV is a second heater that heats the ammonium sulfate mother liquor (6) concentrated in the first evaporator C1 [>, and this second heater αυ
The steam from the first evaporator 0Q is used as the heat source. Q3 is the ammonium sulfate mother liquor (
6) to produce crystalline ammonium sulfate 04), ammonium sulfate mother liquor (6) overflowing from the second evaporator 0; is stored in an overflow tank 0Q, and then
Ammonium sulfate mother liquor (6) in the first evaporator 0Q and the first heater (9) gate
It is configured to be returned to the circulation line. Further, the upper ammonium sulfate mother liquor (6) of the second evaporator 03 is returned to the second heater αV again. Note that uQ is high temperature cooling water (4)
cooling tower (171 indicates each pump).

With such a configuration, the conventional ammonium sulfate production apparatus operated as follows. First, the exhaust gas (3) leaving the coke oven (1) is passed through a primary cooler (2) and then led to an absorption tower (5). The purpose of passing through the primary cooler (2) is to precipitate tar, naphthalene, etc. in the exhaust gas (3), and the temperature of the exhaust gas (3) before entering the primary cooler (2) is 80°C. The temperature of the exhaust gas (3) exiting from 2) is about 20°C. On the other hand, the temperature of the cooling water (4) used in the primary cooler (2) is about 60 to 70°C. The ammonium sulfate mother liquor (6) produced in the absorption tower (5) is temporarily stored in a tank (8), and the temperature of the ammonium sulfate mother liquor (6) here is about 85 to 42°C.

The ammonium sulfate mother liquor (6) stored in the tank (8) is then
The ammonium sulfate mother liquor (6) is introduced into the circulation line between the evaporator 01 and the first heater (9) and heated by the first heater (9). As a result, the ammonium sulfate mother liquor (6) reaches a temperature of around 70"C and is led to the first evaporator OQ. The temperature of the ammonium sulfate mother liquor (6) concentrated in the first evaporator is 65 to 69 °C. Next, the concentrated sulfur mother liquor (6) is transferred to the second evaporator a →
The ammonium sulfate mother liquor (6) is introduced into the circulation line between the and the second heater θυ, heated by the second heater 0υ, and then introduced to the second evaporator a. The temperature of the ammonium sulfate mother liquor (6) concentrated in the second evaporator (131) becomes 51 to 54°C, and crystalline ammonium sulfate a→ is generated at the bottom of the second evaporator 03.Crystalline ammonium sulfate 04) is taken out to the outside by a slurry pump αη, and then dehydrated and dried.

However, according to such conventional ammonium sulfate production equipment, the high-temperature cooling water (4) that has undergone heat exchange in the primary cooler (2) is not effectively utilized by simply guiding it to the cooling tower αQ. Although each evaporator requires heat, it has the disadvantage that the cooling water (4) heated to a temperature of <60 to 70° C. is wasted.

OBJECTS OF THE INVENTION It is an object of the present invention to provide an apparatus for producing ammonium sulfate from coke oven gas, which eliminates the above-mentioned conventional drawbacks.

Structure of the Invention In order to achieve the above object, the apparatus for producing ammonium sulfate from coke oven gas of the present invention includes a plastic cooler that cools the exhaust gas discharged from the coke oven by exchanging heat with cooling water;
an absorption tower that absorbs ammonia from the exhaust gas cooled by the primary cooler to produce ammonium sulfate mother liquor; a first heater that heats the ammonium sulfate mother liquor produced in the absorption tower; a first evaporator for condensing ammonium sulfate mother liquor; a second heater for heating the ammonium sulfate mother liquor concentrated in the first evaporator; and a second heater for heating the ammonium sulfate mother liquor concentrated in the first evaporator; A heat exchanger connected in parallel with the first heater and configured to heat exchange a part of the ammonium sulfate mother liquor generated in the absorption tower with lithium bromide in an ammonium sulfate production apparatus having a second evaporator that generates ammonium sulfate. , and the high-temperature cooling water that has undergone heat exchange in the primary cooler is used as a heat source for generating water vapor to be absorbed by the lithium bromide. This makes it possible to effectively utilize high-temperature cooling water.

Examples and effects Hereinafter, one embodiment of the present invention will be described based on the drawings.

FIG. 2 shows the main parts of the present ammonium sulfate manufacturing apparatus, and the configurations not shown are the same as those shown in FIG. 1, so the explanation will be omitted. In the figure, (18 is an absorption heat pump provided in parallel connection with the first heater (9), the first and second heat exchangers (4) adjacent to each other, and the third and third heat exchangers (4) adjacent to each other). Fourth
It is composed of a heat exchanger (2υ (E)). The diameter is the communication hole provided in the center of the adjacent wall (C) between the first and second heat exchangers, and the number 9 is the communication hole between the eighth and Fourth heat exchanger sputum
This is a communication hole provided in the center of the adjacent wall (c). (
c) is pulled out from the bottom of the fourth heat exchanger (c) and
Water led to the upper part of the heat exchanger θ1, (2) is the second heat exchanger 8
Lithium bromide is drawn out from the bottom of the vessel (4) and guided to the top of the third heat exchanger Qυ, and is also drawn out from the bottom of the eighth heat exchanger 6U and guided to the top of the second heat exchanger ( LiB+-aqueous solution). The ammonium sulfate mother liquor (6) generated in the absorption tower (5) is led to the first heater (9), while a part of it is led to the second heat exchanger (4) of the absorption heat pump a→. It has a configuration in which it is heated by lithium bromide (e) in the second heat exchanger and then guided to the first evaporator a1.

Further, a portion of the high temperature cooling water (4) that has completed heat exchange in the primary cooler (2) is guided to the third heat exchanger Qv via the first heat exchanger 01). After providing its high heat in the third heat exchanger (11 (=!I), cooling tower 0Q
It is said that the structure is guided by. (A) is cooling water separately introduced from outside, which cools and condenses the refrigerant vapor in the fourth heat exchanger (E).

The effects of the above configuration will be explained below.

First, install an i 450 in the primary cooler (2).
The cooling water (4) passed through the coke oven (1)
It exchanges heat with the exhaust gas (3) and becomes high-temperature cooling water (4) of about 65℃, some of which is exposed to the noise of the first heat exchanger of the absorption heat pump (towards), and the rest is sent to the cooling tower O→ be guided. In the first heat exchanger 09), this cooling water (4) acts as a heat medium for generating water vapor), and the generated water vapor (g) at about 60°C is passed through the communication hole (a) to the second heat exchanger. Enter the cage. Then, for example, 48
Lithium bromide (c) of % by weight absorbs this water vapor (g) and is diluted to 40% by weight, and generates absorption heat at a temperature level of about 73 to 76°C. Therefore,
The ammonium sulfate mother liquor (6) (approximately 40°C) from the absorption tower (5) led to the second heat exchanger (4) is heated to 6
It is heated to about 9° C. and guided to the first evaporator θQ.

The cooling water (4) leaving the first heat exchanger θ0 reaches a temperature of about 62°C and enters the third heat exchanger ψυ, and then enters the second heat exchanger (E).
It works to regenerate lithium bromide (c) diluted with That is, the diluted lithium bromide (E) drawn out from the bottom of the second heat exchanger (A) is led to the upper part of the eighth heat exchanger Qυ, and is reduced by approximately 0.0
It generates 6% aabs of water vapor (to 43% by weight of concentrated lithium bromide). The cooling water (4) leaving the eighth heat exchanger Q0 reaches a temperature of about 59° C. and is led to the cooling tower θQ. On the other hand, the water vapor generated in the third heat exchanger Qυ enters the fourth heat exchanger (A) through the communication hole (C), and the cooling water flows through the fourth heat exchanger (2). It is cooled by heat exchange. As a result, water vapor (1) turns into water (a) and is drawn out from the bottom of the fourth heat exchanger (a) and guided to the top of the first heat exchanger (a). In addition, the cooling water (E) is, for example, 1780
/h, and the temperature before entering the fourth heat exchanger (A) is 81°C1, and the temperature is about 33.5°C.

FIG. 3 shows the relationship between these temperatures and pressures. In the figure, point (A) is the first heat exchanger (1, point (0) is the second heat exchanger
Heat exchanger (E), (C) point is the third heat exchanger Q]),)
The point corresponds to the fourth heat exchanger).

Note that the calorific value (QA) for absorption of lithium bromide (c) in the second heat exchanger is given by the following equation.

QA=Hse-1-WJi ・HJi -(Wii +
1) ・Hl.

Here, Hse: Amount of water vapor in the first heat exchanger (W/i of water vapor generated in ) enthalpy of lithium bromide supplied to ) Hf! o: Enthalpy of lithium bromide (to lithium bromide discharged from the second heat exchanger However, if we consider only the steam consumption amount, for example, in the case of an 8.4//H ammonium sulfate manufacturing equipment, the steam unit price is 4.0001"/T, and the operating time is 8,000.
((s□oMCal/'I'ammonium sulfate X8.4" ammonium sulfate/H)
/6ooMca1/T・Steam JX 4,000 yen/T・Steam X 8,000H=224. The annual gain will be 1,000,000 yen.

Effects of the Invention According to the present invention, high-temperature cooling water that has undergone heat exchange in the primary cooler can be effectively utilized. Therefore, it is possible not only to reduce the load on the cooling tower into which the cooling water is introduced by the amount of heat recovered, but also to limit operating costs.

[Brief explanation of the drawing]

Fig. 1 is an overall process diagram of a conventional apparatus for recycling ammonium sulfate from coke oven gas, Figs. 2 and 8 show an embodiment of the present invention, and Fig. Figure 3 is a schematic diagram of the main parts of the equipment for producing ammonium sulfate, and is a diagram showing the relationship between temperature and pressure. (1) Coke oven, (2) Primary cooler, exhaust gas, (4) Cooling water, (5) Absorption tower, 6) Ammonium sulfate F liquid, (1) First heater, Q (ν First evaporator, (
9th month - 3rd heater, 0th stage, 2nd evaporator, 0th stage Crystalline ammonium sulfate, 08) Absorption heat pump, (7) Lithium bromide, ■
Mizuaki Agent Yoshihiro Morimoto Tobuki

Claims (1)

[Claims] 1. A primary cooler that cools exhaust gas emitted from a coke oven by exchanging heat with cooling water, an absorption tower that absorbs ammonia from the exhaust gas cooled by the primary cooler and generates ammonium sulfate fJ liquid, and the absorption tower a first heater for heating the ammonium sulfate mother liquor produced in the first heater; a first evaporator for concentrating the ammonium sulfate mother liquor heated by the first heater; and a first heater for heating the ammonium sulfate mother liquor concentrated in the first evaporator. In an ammonium sulfate production apparatus having a second heater and a second evaporator for concentrating the ammonium sulfate mother liquor heated by the second heater to produce crystalline ammonium sulfate, the apparatus is U-connected in parallel with the first heater. , a heat exchanger is provided to heat-exchange a part of the ammonium sulfate mother liquor produced in the absorption tower with lithium bromide, and the heat exchanger is used as a heat source for generating water vapor to be absorbed by the lithium bromide. An apparatus for producing ammonium sulfate from coke oven gas, characterized by using high-temperature cooling water that has been processed.