CN102515210B

CN102515210B - Method for producing potassium bicarbonate through self-carbonization multiple-effect cross flow continues evaporation crystallization

Info

Publication number: CN102515210B
Application number: CN2011103310383A
Authority: CN
Inventors: 王国平; 钱雪明; 陈阳贵; 汪贤玉; 涂永福; 关卫军; 钱建春; 何官明; 仇玉娟; 曾邵平
Original assignee: ZHEJIANG DAYANG CHEMICAL CO Ltd
Current assignee: Zhejiang Dayang Biotech Group Co., Ltd.
Priority date: 2011-10-27
Filing date: 2011-10-27
Publication date: 2013-11-27
Anticipated expiration: 2031-10-27
Also published as: CN102515210A

Abstract

The invention discloses a method for producing potassium bicarbonate through self- carbonization multiple-effect cross flow continues evaporation crystallization, comprising the following steps: mixing a potassium bicarbonate ion exchange solution containing ammonium bicarbonate with a potassium bicarbonate mother solution containing potassium carbonate to obtain a mixed feed liquid; preheating the feed liquid, then putting the preheated feed liquid into a desorption self-carbonization tower to carrying out low temperature desorption self-carbonization; letting the feed liquid flowing out from the desorption self-carbonization tower successively enter an III-effect evaporator, an II-effect evaporator, an I-effect evaporator and an IV-effect evaporator for processing to obtain a solid-liquid mixture; separating the obtained solid-liquid mixture by a centrifugal machine to obtain potassium bicarbonate crystals and a potassium bicarbonate mother liquid containing potassium carbonate; drying and sieving the potassium bicarbonate crystals by a drying machine, and then packaging and putting in storage; and respectively putting the potassium bicarbonate mother liquid containing potassium carbonate into the II-effect evaporator and a liquid storage tank II. According to the invention, the energy consumption in the process of potassium bicarbonate evaporation can be remarkably reduced, and the particle size in the crystallization of potassium bicarbonate and the product quality are improved or controlled.

Description

From carbonization multiple-effect cross-flow continuous evaporative crystallization, produce the method for saleratus

Technical field

The present invention relates to chemical industry and resource and environment technical field, particularly relate to a kind of method of producing saleratus from carbonization multiple-effect cross-flow continuous evaporative crystallization.

Background technology

Saleratus (Potassium bicarbonate) is important industrial chemicals, main as producing salt of wormwood, Potassium ethanoate, potassium arsenite etc., also for industries such as medicine, food, agricultural and fire-fighting mediums, saleratus is widely used as food raising agent and quality improver in recent years, and its development is more and more paid attention to.Saleratus is for producing the raw material of salt of wormwood, salt of wormwood is widely used in the industries such as chemical industry, light industry, picture tube glass bulb, pharmacy, food, welding electrode and Non-ferrous Metallurgy, therefore the saleratus market outlook are wide, and ion exchange method and ionic membrane-electrolytic process are to produce at present saleratus and the main production method of salt of wormwood.Ion-exchange membrane electrolysis is by electrolytic chlorination potassium, at first obtain potassium hydroxide and by product chlorine, potassium hydroxide makes saleratus by carbonating again, this technique has the advantages such as constant product quality, save energy and three-waste pollution are few, but need to be from import equipment and technology, therefore invest radix large, return period is long, and short duration, inherent China can be by spread.The processing method of producing saleratus and salt of wormwood by ion exchange method has the advantages such as the excellent and less investment of quality product, manufacturing enterprise adopts by most domestic, because its three-waste pollution seriously reaches the high impact of energy consumption, once once by National Development and Reform Committee, listed in superseded technique, therefore domestic many enterprises stop production and close or change the line of production.In recent years, research of technique by the scientific research personnel of enterprise, realized the ion-exchange closed cycle, solved the three-waste pollution problem, aspect reducing energy consumption, also carry out simultaneously large quantity research, achieve notable results, the state of the art of current ion exchange method and ion-exchange membrane electrolysis gap are constantly dwindled, and product is occupied an leading position on market at home.

Patent CN101186317A discloses that a kind of technological equipment investment is few, energy consumption is low and the salt of wormwood preparation method of non-pollution discharge, and it passes into coal combustion flue gas or lime-kiln gas in ammoniacal liquor after the water dust-removal and desulfurizing, make (NH ₄) ₂CO ₃Solution, add Ni (OH) ₂And KCl, pass into ammonia and isolate Ni (NH ₃) Cl ₂Precipitation, K ₂CO ₃Ammonia soln is transferred to container again, and pressurization passes into ammonia or adds liquefied ammonia, the solution layering, and upper strata is supersaturation ammoniacal liquor, lower floor is saturated K ₂CO ₃Contain ammonia solution, obtain K with extraction process ₂CO ₃Contain the ammonia saturated solution; By K ₂CO ₃Contain ammonia saturated solution heating evaporation, after deamination, filter out residual NiCO ₃Rear evaporate to dryness obtains K ₂CO ₃Product; Ni (NH ₃) Cl ₂Water-soluble, add lime, after the heating evaporation deamination is complete, filter out Ni (OH) ₂Recycle, filtrate concentrates to obtain CaCl ₂Product, this complex operation, be difficult to realize industrialization.

Traditional ion exchange method is produced saleratus and salt of wormwood and all be take Repone K and bicarbonate of ammonia and be raw material, by Zeo-karb, exchange, the saleratus exchange solution that must contain bicarbonate of ammonia, then packing warehouse-in after ammonia desorb, evaporation concentration, carbonating, crystallisation by cooling, centrifugation and drying.Chinese patent CN200910068696.0 discloses a kind of processing method of method for producing potassium carbonate by ion exchange, this technique mainly comprises the unit such as desorb, evaporation, absorption, carbonating, crystallization and drying, processing step is: ion-exchange is decomposed after completing the liquid preheating in desorption tower, then enter the triple effect evaporation unit, complete evaporation of liquid enters carbon dioxide absorption tower (being to carry out the carbonation reaction of 2-4 hour under 0.4-0.8MPa at pressure), and salt of wormwood is all turned to saleratus by carbonic acid.Carbonating carbon dioxide used is from desorption tower and moisture eliminator, and the ammonia that desorption tower decomposes is absorbed as ammoniacal liquor by the ammonia absorption tower and does dosing and use.The saleratus crystallization is carried out drying again after whizzer dries, salt of wormwood finished product packing warehouse-in.The existing ash furnace of this invention cancellation workshop section, reduced environmental pollution, remove non-condensable gases thorough, improved evaporation heat transfer coefficient, carbonic acid gas centralized collection concentration is high, reduces the carbonating time, improved production efficiency, save material, reduce production costs, significantly improved economic benefit and social benefit.But this process using following current triple effect evaporation system, and vaporization temperature is higher, steam mono-consumption is relatively high, high temperature causes the saleratus of 12.5%-33.8% to be decomposed into salt of wormwood, affects follow-up crystallization and quality product (equipment corrosion increase iron ion content), therefore need to could meet subsequent production by increasing the carbonating operation, extend production process and increased facility investment, energy consumption also significantly increases, and its production cost is also relatively high, the market competitiveness also a little less than.

Chinese patent CN200810164153.4 provides a kind of Potassium Carbonate Production, at bicarbonate of ammonia and Repone K after ion-exchange, to mixing solutions, adopt decompression low temperature to evaporate, thereby make, only have a small amount of saleratus to be converted into salt of wormwood, the carbonic acid gas that the bicarbonate of ammonia decomposition produces in the reduction vaporization process simultaneously carries out from carbonization salt of wormwood, thereby removed carbonation from, realized that low temperature is from process for carbonization production, reduced energy consumption, coal consumption drops to 1.3 tons by 1.8 tons of old technique, and power consumption is down to 270 kilowatt-hours from 450 kilowatt-hours.In evaporative process, because decomposing the ammonia produced, bicarbonate of ammonia carries out reuse by after absorbing, being returned to ion-exchange process, the ton product consumption of main raw material Repone K and bicarbonate of ammonia is respectively 1.25 tons and 1.60 tons and drops to 1.153 tons and 1.335 tons, has reduced simultaneously the corrosion to equipment.Ion-exchange side product sodium chloride solution, by evaporation concentration, obtains ammonium chloride product after crystallization, solved the difficult problem of ammonia and nitrogen pollution.This technology is in medium level in the method for producing potassium carbonate by ion exchange industry, but production cost and quality product and ion-exchange membrane electrolysis also have certain gap, and most importantly steam and power consumption are high, and the product grain size number is uncontrollable.

Method for producing potassium carbonate by ion exchange and saleratus, gordian technique reduce exactly three-waste pollution and control and reduce energy consumption.A kind of Potassium Carbonate Production that patent CN200810164153.4 provides, by ion-exchange closed cycle and weak ammonia reuse, substantially solved the three-waste pollution problem, but the lower concentration nitrogen-containing wastewater produced in evaporating concentration process fails thoroughly to administer, it adopts triple effect evaporation technique simultaneously, there is no fine solution steam mono-consumption and product quality problem.Because ion-exchange completes saleratus content low (14-18% left and right) in liquid, large quantity of moisture need be evaporated to the requirement that could meet the back operation.Past, some small-scale producer adopted single-effect evaporation technique, and energy consumption is higher, and in scale operation, the energy consumption problem of evaporation is particularly outstanding.For save energy, just adopt multiple-effect evaporation technique can reach energy-conservation purpose.Past attempts has the people to work out technique in three-effect countercurrent evaporation technique, by trial run, energy-saving effect is better, but the I single-effect evaporator is owing in temperature, pressure and concentration, all under higher severe environment, moving, the equipment corrosion speed, also affect simultaneously quality product, the descendant has proposed the system of three-effect downstream evaporator process program for the problem existed, solved to a great extent the problem of equipment corrosion, but the difficult problem of steam mono-consumption is put forward again again, how to solve the major technique key that contradiction between power consumption and equipment and quality product becomes method for producing potassium carbonate by ion exchange.

Chinese patent CN200710130643.8 provides a kind of multifunctional multiple-effect automatic continuous evaporative crystallization technique and crystallizer, this invention technology is: after the unsaturated aqueous solution of material or organic solvent are carried out to preheating, by multiple-effect evaporator, feed liquid is carried out to consecutive evaporation, the temperature of each effect evaporation reduces gradually, vacuum tightness increases gradually, when feed concentration reaches capacity, enter crystallizer and carry out flash crystallization, product after crystallization carries out solid-liquid separation in whizzer, unsaturated solution after centrifugal is sent back to the further evaporative crystallization of equipment, water or the organic solvent of evaporation recycle after cooling, realize producing continuously.(1) this invention multiple-effect automatic continuous evaporative crystallization technique is described in counter-current process, feed liquid is after the multiple-effect consecutive evaporation, through take away pump, saturated feed liquid is sent into to 1st effective evaporator, and carry out pump circulation by the forced circulation pump be located between 1st effective evaporator and crystallizer, realize flash crystallization, now the unsaturated aqueous solution of material or organic solvent directly enter 2nd effect evaporator, from 2nd effect evaporator, start to carry out the multiple-effect consecutive evaporation, 2nd effect evaporator utilizes the secondary steam of crystallizer generation as thermal source.Its adopts the secondary steam that produces in crystallizer flash vaporization process directly as the thermal source of 2nd effect evaporator.If the secondary steam temperature that flash crystallization produces is low, can't meet the required heat requirement of 2nd effect evaporator, say nothing of the thermal source of the secondary steam of recycling 2nd effect evaporator generation as triple-effect evaporator, if flash vaporization point is too high, not applicable for those materials (as saleratus) that are suitable for low-temperature evaporation crystallization or thermo-sensitivity, therefore its applicability is just restricted, let alone energy-saving and cost-reducing.(2) this invention multiple-effect automatic continuous evaporative crystallization technique is described in cross-flow technique, feed liquid is after the multiple-effect consecutive evaporation, through take away pump, saturated feed liquid is sent into to 1st effective evaporator, utilize the characteristic that 2nd effect evaporator is higher than 1st effective evaporator vacuum tightness, saturated feed liquid is sucked to 2nd effect evaporator, and carry out pump circulation by the forced circulation pump be located between 2nd effect evaporator and crystallizer, realize flash crystallization, now the unsaturated aqueous solution of material or organic solution directly enter triple-effect evaporator, start to carry out the multiple-effect consecutive evaporation from triple effect.(3) this invention multiple-effect automatic continuous evaporative crystallization technique is described in following current technique, feed liquid is after the multiple-effect consecutive evaporation, directly enter the crystallizer be connected with last single-effect evaporator, carry out pump circulation by the forced circulation pump be located between this vaporizer and crystallizer, realize flash crystallization.This following current evaporation adds continuous evaporative crystallization technique, solved due to the severe operating environment of the high-temperature high concentration etching problem to 1st effective evaporator, but it does not have the high difficult problem of fine solution steam consumption.

Summary of the invention

The technical problem to be solved in the present invention provides a kind of method of producing saleratus from carbonization multiple-effect cross-flow continuous evaporative crystallization, it can significantly reduce the energy consumption in the saleratus evaporative process, improve or control grain size number and the quality product of saleratus, thoroughly solve the reuse problem of lower concentration nitrogen-containing wastewater, can exempt the carbonating operation, really realize the purpose that recycling economy and low-carbon (LC) are produced, improve the competitive edge of enterprise.

In order to solve the problems of the technologies described above, the invention provides a kind of method of producing saleratus from carbonization multiple-effect cross-flow continuous evaporative crystallization, comprise: saleratus mother liquor low-temperature desorption from carbonization, ammonia absorb, the saleratus multiple-effect evaporation is concentrated, saleratus crystallisation by cooling, centrifugation and dry packing

Specifically comprise the following steps successively:

1), setting contains the saleratus ion exchanged soln of bicarbonate of ammonia in reservoir I, and the saleratus mother liquor that contains salt of wormwood is set in reservoir II;

After containing the saleratus ion exchanged soln of bicarbonate of ammonia and containing the saleratus mother liquor mixing of salt of wormwood, obtain mixed liquor; Described mixed liquor relies on pump successively by Verticle pipe steam water of condensation interchanger and plate-type heat exchanger, obtains feed liquid after preheating;

2), after described preheating, feed liquid is carried out low-temperature desorption from carbonization through being pumped into desorb from carbonating tower;

3) the feed liquid dependence pump, flowed out from carbonating tower from desorb enters in the III single-effect evaporator and carries out evaporation concentration;

4), the material after the III single-effect evaporator is concentrated relies on to be pumped in the II single-effect evaporator and carries out evaporation concentration;

5), the material after the II single-effect evaporator is concentrated relies on to be pumped in the I single-effect evaporator and carries out evaporation concentration;

6), the dependence of the material after the I single-effect evaporator is concentrated is pumped into the IV single-effect evaporator and concentrates flash crystallization;

7), the material after the crystallization of IV single-effect evaporator carries out crystallisation by cooling by pump delivery to cooling crystallizer;

8), the solidliquid mixture after crystallisation by cooling separates by whizzer, obtain the saleratus crystallization and contain the saleratus mother liquor of salt of wormwood;

9), packing warehouse-in after the dry screening of saleratus crystal drying device; The saleratus mother liquor that contains salt of wormwood is sent into respectively II single-effect evaporator and reservoir II by pump.

Improvement as the method from carbonization multiple-effect cross-flow continuous evaporative crystallization production saleratus of the present invention:

In the saleratus ion exchanged soln that contains bicarbonate of ammonia in reservoir I, the concentration of bicarbonate of ammonia is 40-60g/L, and the concentration of saleratus is 220-240g/L;

In the saleratus mother liquor that contains salt of wormwood in reservoir II, the concentration of salt of wormwood is 100-120g/L, the concentration 400-440g/L of saleratus;

The flow velocity of the saleratus ion exchanged soln that control contains bicarbonate of ammonia from flowing out in the flow velocity that flows out reservoir I and the saleratus mother liquor reservoir II that contains salt of wormwood, thereby the concentration that makes bicarbonate of ammonia in mixed liquor is 20-40g/L, the concentration that contains salt of wormwood is 30-60g/L, and the concentration that contains saleratus is 280-320g/L.

As further improvements in methods of producing saleratus from carbonization multiple-effect cross-flow continuous evaporative crystallization of the present invention:

Step 5) secondary steam that in, the I single-effect evaporator produces is as step 4) heating steam of II single-effect evaporator, step 4) secondary steam that produces of II single-effect evaporator is as step 3) heating steam of III single-effect evaporator, step 3) secondary steam that produces of III single-effect evaporator is as step 6) heating steam of IV single-effect evaporator.

As further improvements in methods of producing saleratus from carbonization multiple-effect cross-flow continuous evaporative crystallization of the present invention: step 6) in, the secondary steam of IV single-effect evaporator generation is divided into 2 parts:

A part extracts with after the middle pressure steam that comes from boiler mixes, as step 5 by heat pump) heating steam of I single-effect evaporator; After described mixing, Steam pressure control is between 0.004-0.006MPa;

Another part (part of namely not taken away by heat pump) enters vacuum system after condenser is cooling, control IV single-effect evaporator vacuum tightness between negative 0.088-0.092MPa.

As further improvements in methods of producing saleratus from carbonization multiple-effect cross-flow continuous evaporative crystallization of the present invention: step 2) in, desorb is from carbonating tower steam condensate and step 3) steam condensate that produces of I single-effect evaporator returns to heat power plant, is used as oiler feed.

As further improvements in methods of producing saleratus from carbonization multiple-effect cross-flow continuous evaporative crystallization of the present invention: step 2) desorb is decomposed from carbonating tower bicarbonate of ammonia the ammonia that produces and by plate-type heat exchanger and the cold doubtful device of vertical pipe type, is connected into water-circulating pump vacuum system (clear for drawing after cooling successively again, this water-circulating pump vacuum system has been done to omit and has been processed in Fig. 1, it is between vertical tube type condenser and saleratus dissolving tank), by deionized water, absorb ammonia and produce dilute ammonia solution, inhale the weak ammonia and the step 4 that after ammonia, obtain) the II single-effect evaporator, step 3) III single-effect evaporator and step 6) steam condensate that produces of IV single-effect evaporator mixes and is transported to the bicarbonate of ammonia dissolving tank, as the water that dissolves the bicarbonate of ammonia raw material.

As further improvements in methods of producing saleratus from carbonization multiple-effect cross-flow continuous evaporative crystallization of the present invention: step 6) the secondary steam water of condensation of IV single-effect evaporator is delivered to ion-exchanger, cleans the resin water as ion-exchange process.

As further improvements in methods of producing saleratus from carbonization multiple-effect cross-flow continuous evaporative crystallization of the present invention: step 1), mixed liquor is after Verticle pipe steam water of condensation interchanger and board-like tail gas heat exchanger preheating, temperature of charge rises to 50 ℃ by 35 ℃, steam condensate in Verticle pipe steam water of condensation interchanger from desorb from carbonating tower steam condensate and step 3) steam condensate that the I single-effect evaporator produces, the tail gas in described board-like tail gas heat exchanger decomposes the secondary steam produced from carbonization from carbonating tower from desorb.Above-mentioned these can be as the recycling of secondary energy.

As further improvements in methods of producing saleratus from carbonization multiple-effect cross-flow continuous evaporative crystallization of the present invention: I single-effect evaporator temperature is controlled at 85-87 ℃, II single-effect evaporator temperature is controlled at 73-75 ℃, III single-effect evaporator temperature is controlled at 63-65 ℃, and IV single-effect evaporator temperature is controlled at 53-59 ℃;

I single-effect evaporator vacuum degree control is at negative pressure 0.056-0.060MPa, II single-effect evaporator vacuum degree control is at negative pressure 0.070-0.074MPa, III single-effect evaporator vacuum degree control is at negative pressure 0.078-0.082MPa, and IV single-effect evaporator vacuum degree control is at negative pressure 0.088-0.092MPa.

As further improvements in methods of producing saleratus from carbonization multiple-effect cross-flow continuous evaporative crystallization of the present invention: I single-effect evaporator, II single-effect evaporator and III single-effect evaporator are the vertical pipe type falling-film evaporator, and the IV single-effect evaporator is DTB type continuous evaporating crystallizer.

Under above-mentioned industry control of the present invention is controlled:

It is 6-10g/L that I single-effect evaporator discharge feed liquid contains bicarbonate of ammonia, containing salt of wormwood is 70-110g/L, containing saleratus is 460-520g/L, it is 8-12g/L that II single-effect evaporator discharge feed liquid contains bicarbonate of ammonia, containing salt of wormwood is 30-60g/L, containing saleratus is 380-440g/L, it is 12-16g/L that III single-effect evaporator discharge feed liquid contains bicarbonate of ammonia, containing salt of wormwood is 30-50g/L, containing saleratus is 340-380g/L, it is 5-8g/L that IV single-effect evaporator discharge feed liquid contains bicarbonate of ammonia, contain salt of wormwood 80-120g/L, contain saleratus 480-540g/L, solid-to-liquid ratio is about 10-18% (mass ratio).

Step 2) described decomposition is controlled 60-65 ℃ from the carbonating tower temperature, and vacuum degree control is at negative pressure 0.078-0.082MPa, and Steam pressure control is at 0.4MPa, through low-temperature decomposition after carbonization, material contains bicarbonate of ammonia 14-18g/L, salt of wormwood 20-30g/L, saleratus 300-340g/L.

Step 7) described cooling crystallizer carries out crystallisation by cooling, and temperature of charge is down to 45 ℃ by 53-59 ℃, and solid-to-liquid ratio rises to 18-26% by 10-18%.

Step 8) centrifugal gained saleratus crystallization mean particle size is greater than 2.0mm, and saleratus content is greater than 99.1%.

In the present invention, by step 8) centrifugal gained saleratus mother liquor sneaks into the II single-effect evaporator and carries out evaporation concentration, wherein preferably the mother liquor of 35-75% is admitted to the II single-effect evaporator, more preferably the mother liquor of 45-75% is admitted to the II single-effect evaporator, and the mother liquor that most preferably is 55-65% is admitted to the II single-effect evaporator.

In the present invention, by regulating step 5) in I single-effect evaporator heating steam pressure control the temperature of material in vaporizer, and then, to the adjustment of material Tc in the IV single-effect evaporator, realize controlling or improving saleratus grain size number and production quality control.

Adopting the coal consumption (the mark coal calculates) of 1 ton of salt of wormwood of the every production of method of the present invention is 0.68 ton, and power consumption is 220 kilowatt-hours, and the consumption of main raw material Repone K and bicarbonate of ammonia is respectively 1.141 tons and 1.316 tons.

Operational path of the present invention is summarized as follows: will contain bicarbonate of ammonia is 40-60g/L, containing saleratus is that the saleratus solvent of 220-240g/L is 100-120g/L with wherein containing salt of wormwood, the saleratus mother liquor that contains saleratus 400-440g/L mixes, control in mixed material that to contain bicarbonate of ammonia be 20-40g/L, containing salt of wormwood is 30-60g/L, and containing saleratus is 280-320g/L; Mixed material enters successively the vertical pipe type tail gas heat exchanger by pump and board-like vapor condensation water-to-water heat exchanger carries out preheating, and after preheating, temperature of charge rises to 50 ℃ by 35 ℃; Feed liquid is carried out low-temperature desorption from carbonization through being pumped into desorb from carbonating tower after preheating, decomposition is controlled 60-65 ℃ from the carbonating tower temperature, vacuum degree control is at 0.078-0.082MPa, Steam pressure control is at 0.4MPa, material through decomposing after carbonization contains bicarbonate of ammonia 14-18g/L, salt of wormwood 20-30g/L, saleratus 300-340g/L; Decomposition feed liquid after carbonization is squeezed into the III single-effect evaporator through pump and is carried out evaporation concentration, III single-effect evaporator temperature is controlled 63-65 ℃, vacuum degree control is negative pressure 0.078-0.082MPa, after concentrated, containing bicarbonate of ammonia in material is 12-16g/L, containing salt of wormwood is 30-50g/L, and containing saleratus is 340-380g/L; Material after the III single-effect evaporator is concentrated carries out evaporation concentration by being pumped into the II single-effect evaporator, II single-effect evaporator temperature is controlled 73-75 ℃, vacuum degree control is at negative pressure 0.070-0.074MPa, after concentrated, containing bicarbonate of ammonia in material is 8-12g/L, containing salt of wormwood is 30-60g/L, and containing saleratus is 380-440g/L; Material after the II single-effect evaporator is concentrated carries out evaporation concentration by being pumped into the I single-effect evaporator, I single-effect evaporator temperature is controlled 85-87 ℃, vacuum degree control is at negative pressure 0.056-0.060MPa, Steam pressure control is at 0.004-0.006MPa, after concentrated, containing bicarbonate of ammonia in material is 6-10g/L, containing salt of wormwood is 70-110g/L, and containing saleratus is 460-520g/L; Material after the I single-effect evaporator is concentrated carries out the consecutive evaporation condensing crystal by being pumped into the IV single-effect evaporator, IV single-effect evaporator temperature is controlled 53-59 ℃, vacuum degree control is at 0.088-0.092MPa, after concentrated, containing bicarbonate of ammonia in material is 5-8g/L, contain salt of wormwood 80-120g/L, contain saleratus 480-540g/L, solid-to-liquid ratio is about 10-18% (mass ratio); Material after the IV single-effect evaporator is concentrated carries out crystallisation by cooling by pump delivery to cooling crystallizer, and temperature is reduced to 45 ℃ by 53-59 ℃, and solid-to-liquid ratio rises to 22-26% (mass ratio) by 14-18% (mass ratio); Solidliquid mixture after crystallisation by cooling separates by whizzer, obtains the saleratus crystallization and contains the saleratus mother liquor of salt of wormwood; Packing warehouse-in after centrifugal gained saleratus crystal drying screening; The saleratus mother liquor that centrifugal gained contains salt of wormwood requires to send into respectively II single-effect evaporator or mother liquor reservoir by pump according to processing parameter, wherein preferably the mother liquor of 35-75% is admitted to the II single-effect evaporator, more preferably the mother liquor of 45-75% is admitted to the II single-effect evaporator, the mother liquor that most preferably is 55-65% is admitted to the II single-effect evaporator, the mother liquor be admitted in the II single-effect evaporator dilutes and heat effect through feed liquid, in mother liquor, a large amount of tiny crystalline particles are dissolved again, have improved the grain size number of follow-up saleratus.

Method of producing saleratus from carbonization multiple-effect cross-flow continuous evaporative crystallization of the present invention, contain the saleratus mother liquor of salt of wormwood by desorption tower, carrying out low-temperature desorption from carbonization, exempt follow-up carbonating operation, when significantly reducing production energy consumption, also improved the quality of product.

As a kind of method of producing saleratus from carbonization multiple-effect cross-flow continuous evaporative crystallization of the present invention, can be by regulating step 5) in I single-effect evaporator (13) heating steam pressure control the temperature of material in vaporizer, and then control step 6) Tc of IV single-effect evaporator (15) material, realize saleratus crystallization particle diameter and quality are controlled.

The present invention adopts quadruple effect continuous evaporative crystallization system, by heat pump, extract the end effect steam in the IV single-effect evaporator and come from the heating steam of the high pressure steam mixed steam of boiler as the I single-effect evaporator, the secondary steam that the I single-effect evaporator produces is as the heating steam of II single-effect evaporator, the secondary steam that the II single-effect evaporator produces is as the heating steam of III single-effect evaporator, the secondary steam that the III single-effect evaporator produces is as the heating steam of IV single-effect evaporator, improve steam utilization efficiency, significantly reduced energy consumption.

Annotate: so-called " end effect steam " is exactly to adopt the secondary steam that in multiple-effect evaporator, last effect produces, and is all in general to discharge by vacuum system, does not recycle; And so-called " secondary steam " is exactly in the evaporator evaporation process, due to the secondary steam that the solvent evaporation produces, so-called multiple-effect evaporation is achieved the secondary steam recycling exactly.

The present invention will decompose in carbonating tower bicarbonate of ammonia and decompose the ammonia produced and be connected into the water-circulating pump system after cooling by interchanger again, by deionized water, absorb ammonia and produce dilute ammonia solution, inhale the weak ammonia and the step 4 that after ammonia, obtain) II single-effect evaporator (11), step 3) III single-effect evaporator (9) and step 6) IV single-effect evaporator (15) mixes and is transported to the bicarbonate of ammonia dissolving tank, as the water that dissolves the bicarbonate of ammonia raw material, the utilization ratio that has improved bicarbonate of ammonia has also reduced environmental pollution simultaneously.

The present invention returns desorb to heat power plant as oiler feed from the steam condensate of carbonating tower and the steam condensate of I single-effect evaporator generation, the secondary steam water of condensation that the IV single-effect evaporator produces is delivered to ion-exchange process, as the ion exchange resin water for cleaning, present technique provides good water sources for boiler and ion-exchange process, has also solved the pollution difficult problem of lower concentration nitrogen-containing wastewater simultaneously.

In a word, the present invention compares with common process, has exempted carbonation, cancels ash furnace workshop section, has reduced the required energy consumption of environmental pollution and carbonation; Adopt quadruple effect continuous evaporative crystallization system, by heat pump, extract end effect secondary steam and come from the heating steam of the high pressure steam mixed steam of boiler as the I single-effect evaporator, the secondary steam that the I single-effect evaporator produces is as the heating steam of II single-effect evaporator, the secondary steam that the II single-effect evaporator produces is as the heating steam of III single-effect evaporator, the secondary steam that the III single-effect evaporator produces is as the heating steam of IV single-effect evaporator, comprise that the heat in steam condensate also effectively utilizes, significantly improve steam utilization efficiency, reduced energy consumption; By the adjustment of I single-effect evaporator heating steam pressure, controlled the temperature of material in vaporizer, and then, to the adjustment of material Tc in the IV single-effect evaporator, realized controlling or improving saleratus grain size number and production quality control; The weak ammonia produced in desorb and evaporative process is as the water that dissolves the bicarbonate of ammonia raw material, and the utilization ratio that has improved bicarbonate of ammonia has also reduced environmental pollution simultaneously; Steam condensate and lower concentration nitrogen-containing wastewater fully utilize as oiler feed and ion-exchange process cleaning resin water as heat power plant respectively, for boiler and ion-exchange process provide good water sources, also solved the pollution difficult problem of lower concentration nitrogen-containing wastewater simultaneously.Method from carbonization multiple-effect cross-flow continuous evaporative crystallization production salt of wormwood of the present invention is a kind of green production technique, has both reduced energy consumption, improves again quality product, and environmental contamination reduction, be worth large-scale promotion application simultaneously.

The accompanying drawing explanation

Below in conjunction with accompanying drawing, the specific embodiment of the present invention is described in further detail.

Fig. 1 is the method process flow sheet of producing salt of wormwood from carbonization multiple-effect cross-flow continuous evaporative crystallization of the present invention.

Embodiment

Fig. 1 has provided a kind of device of producing saleratus from carbonization multiple-effect cross-flow continuous evaporative crystallization, comprise reservoir I1, reservoir II2, pump 3, Verticle pipe steam water of condensation interchanger 4, plate-type heat exchanger 5, pump 6, desorb is from carbonating tower 7, pump 8, III single-effect evaporator 9, pump 10, II single-effect evaporator 11, pump 12, I single-effect evaporator 13, pump 14, IV single-effect evaporator 15, pump 16, cooling crystallizer 17, whizzer 18, moisture eliminator 19, pump 20, heat pump 21, condenser 22, vacuum system 23, boiler 24, bicarbonate of ammonia dissolving tank 25, the cold doubtful device 27 of ion-exchanger 26 and vertical pipe type.

The outlet of described reservoir I1 is connected with the opening for feed of reservoir II2, and the discharge port of reservoir II2 is connected with the entrance of Verticle pipe steam water of condensation interchanger 4 by pipeline 101, on pipeline 101, is provided with pump 3.

4 outlets of Verticle pipe steam water of condensation interchanger are connected with the entrance of plate-type heat exchanger 5, and the outlet of plate-type heat exchanger 5 is connected from the top of carbonating tower 7 entrance with desorb by pipeline 103; Desorb is connected with plate-type heat exchanger 5 by pipeline 102 from the top exit of carbonating tower 7.

Desorb is connected with the opening for feed of III single-effect evaporator 9 by pipeline 104 from the material outlet of carbonating tower 7, and the discharge port of III single-effect evaporator 9 is connected with the opening for feed of II single-effect evaporator 11 by pipeline 105, on pipeline 105, is provided with pump 10.The discharge port of II single-effect evaporator 11 is connected with the feeding mouth of I single-effect evaporator 13 by pipeline 106, on pipeline 106, is provided with pump 12; The discharge port of I single-effect evaporator 13 is connected with the feeding mouth of IV single-effect evaporator 15 by pipeline 107, on pipeline 107, is provided with pump 14, and the discharge port of IV single-effect evaporator 15 is connected with the entrance of cooling crystallizer 17 by pipeline 118, on pipeline 118, is provided with pump 16.The outlet of cooling crystallizer 17 is connected with the entrance of whizzer 18; The solid outlet of whizzer 18 is connected with moisture eliminator 19, and the liquid exit of whizzer 18 is connected with reservoir II2 with II single-effect evaporator 11 respectively by pipeline 119 is rear; At pipeline 119, pump 20 is set.

The secondary steam that I single-effect evaporator 13 produces passes to the heating steam of II single-effect evaporator 11 as II single-effect evaporator 11 by pipeline 108; The secondary steam that II single-effect evaporator 11 produces passes to the heating steam of III single-effect evaporator 9 as III single-effect evaporator 9 by pipeline 109; The secondary steam that III single-effect evaporator 9 produces passes to the heating steam of the IV single-effect evaporator 15 of IV single-effect evaporator 15 conducts by pipeline 110.

The secondary steam that IV single-effect evaporator 15 produces is divided into 2 parts:

A part extracts by heat pump 21 and by pipeline 111, passes to I single-effect evaporator 13 after the middle pressure steam that comes from boiler 24 mixes, as the heating steam of I single-effect evaporator 13; Another part (part of namely not taken away by heat pump 21) enters in condenser 22 by pipeline 112, after condenser 22 is cooling, enter vacuum system 23, vacuum system 23 (clear for drawing that be connected with IV single-effect evaporator 15, this structure has been done to omit and has been processed in Fig. 1), vacuum system 23 is controlled the vacuum tightness of IV single-effect evaporator 15.

Desorb is returned to heat power plant by pipeline 113 from the steam condensate of carbonating tower 7, as boiler 24 feedwater; In like manner, the steam condensate that I single-effect evaporator 13 produces returns to heat power plant by pipeline 113, as boiler 24 feedwater.

Desorb exports pipeline 102 successively from the gas of carbonating tower 7 (for ammonia) and is connected with plate-type heat exchanger 5, after plate-type heat exchanger 5 is cooling by the cold doubtful device 27 of vertical pipe type again, be connected into again the water-circulating pump vacuum system and (be a device between the cold doubtful device 27 of vertical pipe type and bicarbonate of ammonia dissolving tank 25, clear for drawing, in Fig. 1, done to omit and processed), the water-circulating pump vacuum system absorbs ammonia by deionized water and produces dilute ammonia solution, inhales the weak ammonia obtained after ammonia and is transported to bicarbonate of ammonia dissolving tank 25.Simultaneously, the steam condensate that IV single-effect evaporator 15 produces all is transported to bicarbonate of ammonia dissolving tank 25 by the steam condensate that pipeline 115, III single-effect evaporator 9 produce by pipeline 116 by the steam condensate that pipeline 114, II single-effect evaporator 11 produce, as the water (this strand water is as the preparation purposes of ion-exchange raw material ammonium bicarbonate soln) that dissolves the bicarbonate of ammonia raw material.

Condenser 22 is connected with ion-exchanger 26 by pipeline 117, thereby makes the secondary steam water of condensation of IV single-effect evaporator 15 be sent to ion-exchanger 26, cleans the resin water as ion-exchange process.

Steam condensate in Verticle pipe steam water of condensation interchanger 4 is from the steam condensate of desorb from carbonating tower 7 steam condensates and 13 generations of step 3I single-effect evaporator, and the tail gas in board-like tail gas heat exchanger 5 decomposes from carbonating tower 7 secondary steam produced from carbonization from desorb.It is used as reusing of energy source.

Embodiment 1, a kind of method of producing saleratus from carbonization multiple-effect cross-flow continuous evaporative crystallization, carry out successively following steps:

1, the saleratus ion exchanged soln that contains bicarbonate of ammonia is set in reservoir I1, the concentration of bicarbonate of ammonia is 50g/L, and the concentration of saleratus is 230g/L; All the other are water.

The saleratus mother liquor that contains salt of wormwood is set in reservoir II2; The concentration of salt of wormwood is 120g/L, the concentration 420g/L of saleratus; All the other are water.

Above-mentioned saleratus ion exchanged soln and saleratus mother liquor obtain mixed liquor after according to the volume flow ratio of 5: 2, mixing; In mixed liquor, contain bicarbonate of ammonia 30g/L, contain salt of wormwood 50g/L, contain saleratus 280g/L.

Mixed liquor enters in Verticle pipe steam water of condensation interchanger 4 and plate-type heat exchanger 5 successively by pipeline 101 under the effect of pump 3, obtain feed liquid after preheating; After preheating, feed liquid rises to 50 ℃ of (notes: 35 ℃ of temperature that refer to the original mixed feed liquid) by 35 ℃.

Steam condensate in Verticle pipe steam water of condensation interchanger 4 is from the steam condensate of desorb from carbonating tower 7 steam condensates and 13 generations of step 3I single-effect evaporator, and the tail gas in board-like tail gas heat exchanger 5 decomposes from carbonating tower 7 secondary steam produced from carbonization from desorb.Said process is undertaken by pipeline 102 and pipeline 113 respectively.

2, after board-like tail gas heat exchanger 5 preheating of flowing out, feed liquid is carried out low-temperature desorption from carbonization under the effect of pump 6, sending into desorb by pipeline 103 in carbonating tower 7; Desorb is controlled 60-65 ℃ from the temperature of carbonating tower 7, and vacuum degree control is at 0.078-0.082MPa, and Steam pressure control is at 0.4MPa.

Through desorb from the decomposition of carbonating tower 7 after carbonizing treatment, from desorb, contain bicarbonate of ammonia 16g/L, salt of wormwood 30g/L, saleratus 320g/L from the feed liquid that carbonating tower 7 flows out.

3, from desorb, by pipeline 104, enter in III single-effect evaporator 9 and carry out evaporation concentration under the effect of pump 8 from the feed liquid that carbonating tower 7 flows out;

The temperature of III single-effect evaporator 9 is controlled 63-65 ℃, and vacuum degree control, at negative pressure 0.078-0.082MPa, contains bicarbonate of ammonia 14g/L, salt of wormwood 40g/L, saleratus 360g/L in concentrated rear material (i.e. material after III single-effect evaporator 9 is concentrated);

4, the material after III single-effect evaporator 9 is concentrated relies on pump 10 to send in II single-effect evaporator 11 and carry out evaporation concentration by pipeline 105;

The temperature of II single-effect evaporator 11 is controlled 73-75 ℃, and vacuum degree control, at negative pressure 0.070-0.074MPa, contains bicarbonate of ammonia 10g/L, salt of wormwood 60g/L, saleratus 440g/L in concentrated rear material (material after II single-effect evaporator 11 is concentrated);

5, the material after II single-effect evaporator 11 is concentrated relies on pump 12 to send in I single-effect evaporator 13 and carry out evaporation concentration by pipeline 106;

I single-effect evaporator 13 temperature are controlled 85-87 ℃, vacuum degree control is at negative pressure 0.056-0.060MPa, and Steam pressure control, at 0.004-0.006MPa, contains bicarbonate of ammonia 8g/L in concentrated rear material (i.e. material after I single-effect evaporator 13 is concentrated), salt of wormwood 110g/L, saleratus 510g/L.

Illustrate: the temperature of controlling I single-effect evaporator 13 interior materials by the heating steam pressure (being vapor pressure) of regulating I single-effect evaporator 13, thereby realize the adjustment to the interior material Tc of IV single-effect evaporator 15, realize controlling or improving saleratus grain size number and production quality control.Be specially: when the heating steam pressure of I single-effect evaporator 13 increased, the interior material Tc of IV single-effect evaporator 15 will raise, and the saleratus grain size number can reduce, and quality product can reduce; Otherwise when the heating steam pressure of I single-effect evaporator 13 reduced, the interior material Tc of IV single-effect evaporator 15 will reduce, the saleratus grain size number can increase, and quality product can improve;

6, the material after I single-effect evaporator 13 is concentrated relies on pump 14 to send into IV single-effect evaporator 15 by pipeline 107 and concentrates flash crystallization;

The temperature of IV single-effect evaporator 15 is controlled 53-56 ℃, vacuum degree control, at negative pressure 0.088-0.092MPa, contains bicarbonate of ammonia 6g/L, salt of wormwood 120g/L in concentrated rear material (being the concentrated rear material of IV single-effect evaporator 15), saleratus 540g/L, solid-to-liquid ratio is about 18% (mass ratio);

7, the material after IV single-effect evaporator 15 condensing crystals is transported to cooling crystallizer 17 by pipeline 118 and carries out crystallisation by cooling under the effect of pump 16;

Thereby make the temperature of material be reduced to 45 ℃ by 53-56 ℃, solid-to-liquid ratio rises to 28% (mass ratio) by 18% (mass ratio).

8, the solidliquid mixture after crystallisation by cooling separates (controlling centrifugal rotational speed is 1200 rev/mins) by whizzer 18, saleratus crystallization and contain the saleratus mother liquor (salt of wormwood content is 120g/L, and saleratus is 440g/L) of salt of wormwood.

Saleratus crystallization mean particle size is greater than 2.0mm, and saleratus content is 99.1%, meets national premium grads quality standard.

9, packing warehouse-in after the dry screening of saleratus crystal drying device 19; The saleratus mother liquor that contains salt of wormwood is divided into 2 tunnels by pipeline 119 under the effect of pump 20: 75% volume is sent into to II single-effect evaporator 11 and carry out evaporating, concentrating and crystallizing again, 25% volume is sent in reservoir II2 and carry out step 1) preparation used.

Annotate: the component content consistence that just can realize guaranteeing " saleratus mother liquor " and " the saleratus mother liquor " in reservoir II2 of centrifugal rear gained according to above-mentioned control processing parameter.

Adopting the coal consumption (the mark coal calculates) of 1 ton of salt of wormwood of the every production of aforesaid method is 0.683 ton, and power consumption is 224 kilowatt-hours, and the consumption of main raw material Repone K and bicarbonate of ammonia is respectively 1.141 tons and 1.319 tons.

Embodiment 2, a kind of method (workflow is with embodiment 1) of producing saleratus from carbonization multiple-effect cross-flow continuous evaporative crystallization:

Steam condensate in Verticle pipe steam water of condensation interchanger 4 is from the steam condensate of desorb from carbonating tower 7 steam condensates and 13 generations of step 3I single-effect evaporator, and the tail gas in board-like tail gas heat exchanger 5 decomposes from carbonating tower 7 secondary steam produced from carbonization from desorb.

The temperature of II single-effect evaporator 11 is controlled 73-75 ℃, and vacuum degree control, at negative pressure 0.070-0.074MPa, contains bicarbonate of ammonia 10g/L, salt of wormwood 55g/L, saleratus 420g/L in concentrated rear material (material after II single-effect evaporator 11 is concentrated);

I single-effect evaporator 13 temperature are controlled 85-87 ℃, vacuum degree control is at negative pressure 0.056-0.060MPa, and Steam pressure control, at 0.004-0.006MPa, contains bicarbonate of ammonia 7g/L in concentrated rear material (i.e. material after I single-effect evaporator 13 is concentrated), salt of wormwood 100g/L, saleratus 500g/L.

Illustrate: the temperature of controlling I single-effect evaporator 13 interior materials by the heating steam pressure (being vapor pressure) of regulating I single-effect evaporator 13, thereby realize the adjustment to the interior material Tc of IV single-effect evaporator 15, realize controlling or improving saleratus grain size number and production quality control.Be specially: when the heating steam pressure of I single-effect evaporator 13 increased, the interior material Tc of IV single-effect evaporator 15 will raise, and the saleratus grain size number can reduce, and quality product can reduce; Otherwise when the heating steam pressure of I single-effect evaporator 13 reduced, the interior material Tc of IV single-effect evaporator 15 will reduce, the saleratus grain size number can increase, and quality product can improve.

The temperature of IV single-effect evaporator 15 is controlled 53-56 ℃, vacuum degree control, at negative pressure 0.088-0.092MPa, contains bicarbonate of ammonia 7g/L, salt of wormwood 110g/L in concentrated rear material (being the concentrated rear material of IV single-effect evaporator 15), saleratus 530g/L, solid-to-liquid ratio is about 16% (mass ratio);

Thereby make the temperature of material be reduced to 45 ℃ by 53-56 ℃, solid-to-liquid ratio rises to 24% (mass ratio) by 16% (mass ratio).

8, the solidliquid mixture after crystallisation by cooling separates (controlling centrifugal rotational speed is 1200 rev/mins) by whizzer 18, saleratus crystallization and contain the saleratus mother liquor (salt of wormwood content is 110g/L, and saleratus is 440g/L) of salt of wormwood.

Centrifugal gained saleratus crystallization mean particle size is greater than 2.0mm, and saleratus content is 99.2%, meets national premium grads quality standard.

9, packing warehouse-in after the dry screening of saleratus crystal drying device 19; The saleratus mother liquor that contains salt of wormwood is divided into 2 tunnels by pipeline 119 under the effect of pump 20: 65% volume is sent into to II single-effect evaporator 11 and carry out evaporating, concentrating and crystallizing again, 35% volume is sent in reservoir II2 and carry out step 1) preparation used.

Adopting the coal consumption (the mark coal calculates) of 1 ton of salt of wormwood of the every production of aforesaid method is 0.678 ton, and power consumption is 218 kilowatt-hours, and the consumption of main raw material Repone K and bicarbonate of ammonia is respectively 1.139 tons and 1.319 tons.

Embodiment 3: a kind of method (workflow is with embodiment 1) of producing saleratus from carbonization multiple-effect cross-flow continuous evaporative crystallization:

The temperature of II single-effect evaporator 11 is controlled 73-75 ℃, and vacuum degree control, at negative pressure 0.070-0.074MPa, contains bicarbonate of ammonia 10g/L, salt of wormwood 45g/L, saleratus 410g/L in concentrated rear material (material after II single-effect evaporator 11 is concentrated);

I single-effect evaporator 13 temperature are controlled 85-87 ℃, vacuum degree control is at negative pressure 0.056-0.060MPa, and Steam pressure control, at 0.004-0.006MPa, contains bicarbonate of ammonia 7g/L in concentrated rear material (i.e. material after I single-effect evaporator 13 is concentrated), salt of wormwood 90g/L, saleratus 490g/L.

The temperature of IV single-effect evaporator 15 is controlled 53-56 ℃, vacuum degree control, at negative pressure 0.088-0.092MPa, contains bicarbonate of ammonia 6g/L, salt of wormwood 75g/L in concentrated rear material (being the concentrated rear material of IV single-effect evaporator 15), saleratus 530g/L, solid-to-liquid ratio is about 16% (mass ratio);

8, the solidliquid mixture after crystallisation by cooling separates (control centrifugal rotational speed be 1200 rev/mins) by whizzer 18, obtains the saleratus crystallization and contains the saleratus mother liquor (salt of wormwood content is 75g/L, and saleratus is 450g/L) of salt of wormwood.

Centrifugal gained saleratus crystallization mean particle size is greater than 2.0mm, and saleratus content is 99.3%, meets national premium grads quality standard.

9, packing warehouse-in after the dry screening of saleratus crystal drying device 19; The saleratus mother liquor that contains salt of wormwood is divided into 2 tunnels by pipeline 119 under the effect of pump 20: 55% volume is sent into to II single-effect evaporator 11 and carry out evaporating, concentrating and crystallizing again, 45% volume is sent in reservoir II2 and carry out step 1) preparation used.

Adopting the coal consumption (the mark coal calculates) of 1 ton of salt of wormwood of the every production of aforesaid method is 0.68 ton, and power consumption is 220 kilowatt-hours, and the consumption of main raw material Repone K and bicarbonate of ammonia is respectively 1.141 tons and 1.316 tons.

Embodiment 4: a kind of method (workflow is with embodiment 1) of producing saleratus from carbonization multiple-effect cross-flow continuous evaporative crystallization:

The temperature of II single-effect evaporator 11 is controlled 73-75 ℃, and vacuum degree control, at negative pressure 0.070-0.074MPa, contains bicarbonate of ammonia 10g/L, salt of wormwood 40g/L, saleratus 400g/L in concentrated rear material (material after II single-effect evaporator 11 is concentrated);

I single-effect evaporator 13 temperature are controlled 85-87 ℃, vacuum degree control is at negative pressure 0.056-0.060MPa, and Steam pressure control, at 0.004-0.006MPa, contains bicarbonate of ammonia 7g/L in concentrated rear material (i.e. material after I single-effect evaporator 13 is concentrated), salt of wormwood 80g/L, saleratus 470g/L.

The temperature of IV single-effect evaporator 15 is controlled 53-56 ℃, vacuum degree control, at negative pressure 0.088-0.092MPa, contains bicarbonate of ammonia 6g/L, salt of wormwood 85g/L in concentrated rear material (being the concentrated rear material of IV single-effect evaporator 15), saleratus 500g/L, solid-to-liquid ratio is about 14% (mass ratio);

Thereby make the temperature of material be reduced to 45 ℃ by 53-56 ℃, solid-to-liquid ratio rises to 20% (mass ratio) by 14% (mass ratio).

8, the solidliquid mixture after crystallisation by cooling separates (control centrifugal rotational speed be 1200 rev/mins) by whizzer 18, obtains the saleratus crystallization and contains the saleratus mother liquor (salt of wormwood content is 80g/L, and saleratus is 430g/L) of salt of wormwood.

Centrifugal gained saleratus crystallization mean particle size is greater than 2.0mm, and saleratus content is 99.4%, meets national premium grads quality standard.

9, packing warehouse-in after the dry screening of saleratus crystal drying device 19; The saleratus mother liquor that contains salt of wormwood is divided into 2 tunnels by pipeline 119 under the effect of pump 20: 45% volume is sent into to II single-effect evaporator 11 and carry out evaporating, concentrating and crystallizing again, 55% volume is sent in reservoir II2 and carry out step 1) preparation used.

Adopting the coal consumption (the mark coal calculates) of 1 ton of salt of wormwood of the every production of aforesaid method is 0.688 ton, and power consumption is 228 kilowatt-hours, and the consumption of main raw material Repone K and bicarbonate of ammonia is respectively 1.141 tons and 1.322 tons.

Embodiment 5: a kind of method (workflow is with embodiment 1) of producing saleratus from carbonization multiple-effect cross-flow continuous evaporative crystallization:

The temperature of II single-effect evaporator 11 is controlled 73-75 ℃, and vacuum degree control, at negative pressure 0.070-0.074MPa, contains bicarbonate of ammonia 12g/L, salt of wormwood 35g/L, saleratus 380g/L in concentrated rear material (material after II single-effect evaporator 11 is concentrated);

I single-effect evaporator 13 temperature are controlled 85-87 ℃, vacuum degree control is at negative pressure 0.056-0.060MPa, and Steam pressure control, at 0.004-0.006MPa, contains bicarbonate of ammonia 7g/L in concentrated rear material (i.e. material after I single-effect evaporator 13 is concentrated), salt of wormwood 70g/L, saleratus 460g/L.

The temperature of IV single-effect evaporator 15 is controlled 53-56 ℃, vacuum degree control, at negative pressure 0.088-0.092MPa, contains bicarbonate of ammonia 6g/L, salt of wormwood 80g/L in concentrated rear material (being the concentrated rear material of IV single-effect evaporator 15), saleratus 490g/L, solid-to-liquid ratio is about 10% (mass ratio);

Thereby make the temperature of material be reduced to 45 ℃ by 53-56 ℃, solid-to-liquid ratio rises to 18% (mass ratio) by 10% (mass ratio).

8, the solidliquid mixture after crystallisation by cooling separates (control centrifugal rotational speed be 1200 rev/mins) by whizzer 18, obtains the saleratus crystallization and contains the saleratus mother liquor (salt of wormwood content is 80g/L, and saleratus is 440g/L) of salt of wormwood.

Centrifugal gained saleratus crystallization mean particle size is 2.0mm, and saleratus content is 99.6%, meets national premium grads quality standard.

9, packing warehouse-in after the dry screening of saleratus crystal drying device 19; The saleratus mother liquor that contains salt of wormwood is divided into 2 tunnels by pipeline 119 under the effect of pump 20: 35% volume is sent into to II single-effect evaporator 11 and carry out evaporating, concentrating and crystallizing again, 65% volume is sent in reservoir II2 and carry out step 1) preparation used.

Adopting the coal consumption (the mark coal calculates) of 1 ton of salt of wormwood of the every production of aforesaid method is 0.688 ton, and power consumption is 231 kilowatt-hours, and the consumption of main raw material Repone K and bicarbonate of ammonia is respectively 1.140 tons and 1.323 tons.

Embodiment 6: a kind of method (workflow is with embodiment 1) of producing saleratus from carbonization multiple-effect cross-flow continuous evaporative crystallization:

Above-mentioned saleratus ion exchanged soln and saleratus mother liquor obtain mixed liquor after according to the volume flow ratio of 1: 1, mixing; In mixed liquor, contain bicarbonate of ammonia 25g/L, contain salt of wormwood 60g/L, contain saleratus 320g/L.

Through desorb from the decomposition of carbonating tower 7 after carbonizing treatment, from desorb, contain bicarbonate of ammonia 15g/L, salt of wormwood 45g/L, saleratus 340g/L from the feed liquid that carbonating tower 7 flows out.

The temperature of III single-effect evaporator 9 is controlled 63-65 ℃, and vacuum degree control, at negative pressure 0.078-0.082MPa, contains bicarbonate of ammonia 12g/L, salt of wormwood 55g/L, saleratus 380g/L in concentrated rear material (i.e. material after III single-effect evaporator 9 is concentrated);

The temperature of II single-effect evaporator 11 is controlled 73-75 ℃, and vacuum degree control, at negative pressure 0.070-0.074MPa, contains bicarbonate of ammonia 10g/L, salt of wormwood 65g/L, saleratus 410g/L in concentrated rear material (material after II single-effect evaporator 11 is concentrated);

I single-effect evaporator 13 temperature are controlled 85-87 ℃, vacuum degree control is at negative pressure 0.056-0.060MPa, and Steam pressure control, at 0.004-0.006MPa, contains bicarbonate of ammonia 6g/L in concentrated rear material (i.e. material after I single-effect evaporator 13 is concentrated), salt of wormwood 85g/L, saleratus 460g/L.

The temperature of IV single-effect evaporator 15 is controlled 53-56 ℃, vacuum degree control, at negative pressure 0.088-0.092MPa, contains bicarbonate of ammonia 5g/L, salt of wormwood 90g/L in concentrated rear material (being the concentrated rear material of IV single-effect evaporator 15), saleratus 520g/L, solid-to-liquid ratio is about 15% (mass ratio);

Thereby make the temperature of material be reduced to 45 ℃ by 53-56 ℃, solid-to-liquid ratio rises to 13% (mass ratio) by 15% (mass ratio).

Centrifugal gained saleratus crystallization mean particle size is 2.0mm, and saleratus content is 99.2%, meets national premium grads quality standard.

Adopting the coal consumption (the mark coal calculates) of 1 ton of salt of wormwood of the every production of aforesaid method is 0.682 ton, and power consumption is 219 kilowatt-hours, and the consumption of main raw material Repone K and bicarbonate of ammonia is respectively 1.141 tons and 1.318 tons.

Embodiment 7: a kind of method (workflow is with embodiment 1) of producing saleratus from carbonization multiple-effect cross-flow continuous evaporative crystallization:

Above-mentioned saleratus ion exchanged soln and saleratus mother liquor obtain mixed liquor after according to the volume flow ratio of 4: 1, mixing; In mixed liquor, contain bicarbonate of ammonia 40g/L, contain salt of wormwood 30g/L, contain saleratus 270g/L.

Through desorb from the decomposition of carbonating tower 7 after carbonizing treatment, from desorb, contain bicarbonate of ammonia 20g/L, salt of wormwood 15g/L, saleratus 300g/L from the feed liquid that carbonating tower 7 flows out.

The temperature of III single-effect evaporator 9 is controlled 63-65 ℃, and vacuum degree control, at negative pressure 0.078-0.082MPa, contains bicarbonate of ammonia 16g/L, salt of wormwood 18g/L, saleratus 330g/L in concentrated rear material (i.e. material after III single-effect evaporator 9 is concentrated);

The temperature of II single-effect evaporator 11 is controlled 73-75 ℃, and vacuum degree control, at negative pressure 0.070-0.074MPa, contains bicarbonate of ammonia 14g/L, salt of wormwood 25g/L, saleratus 370g/L in concentrated rear material (material after II single-effect evaporator 11 is concentrated);

I single-effect evaporator 13 temperature are controlled 85-87 ℃, vacuum degree control is at negative pressure 0.056-0.060MPa, and Steam pressure control, at 0.004-0.006MPa, contains bicarbonate of ammonia 12g/L in concentrated rear material (i.e. material after I single-effect evaporator 13 is concentrated), salt of wormwood 35g/L, saleratus 450g/L.

The temperature of IV single-effect evaporator 15 is controlled 53-56 ℃, vacuum degree control, at negative pressure 0.088-0.092MPa, contains bicarbonate of ammonia 10g/L, salt of wormwood 40g/L in concentrated rear material (being the concentrated rear material of IV single-effect evaporator 15), saleratus 490g/L, solid-to-liquid ratio is about 10% (mass ratio);

8, the solidliquid mixture after crystallisation by cooling separates (control centrifugal rotational speed be 1200 rev/mins) by whizzer 18, obtains the saleratus crystallization and contains the saleratus mother liquor (salt of wormwood content is 55g/L, and saleratus is 420g/L) of salt of wormwood.

Adopting the coal consumption (the mark coal calculates) of 1 ton of salt of wormwood of the every production of aforesaid method is 0.688 ton, and power consumption is 230 kilowatt-hours, and the consumption of main raw material Repone K and bicarbonate of ammonia is respectively 1.143 tons and 1.324 tons.

Embodiment 8: a kind of method (workflow is with embodiment 1) of producing saleratus from carbonization multiple-effect cross-flow continuous evaporative crystallization:

The temperature of IV single-effect evaporator 15 is controlled 59 ℃, vacuum degree control, at negative pressure 0.088-0.092MPa, contains bicarbonate of ammonia 6g/L, salt of wormwood 75g/L in concentrated rear material (being the concentrated rear material of IV single-effect evaporator 15), saleratus 530g/L, solid-to-liquid ratio is about 14% (mass ratio);

Thereby make the temperature of material be reduced to 45 ℃ by 59 ℃, solid-to-liquid ratio rises to 24% (mass ratio) by 14% (mass ratio).

Centrifugal gained saleratus crystallization mean particle size is greater than 1.2mm, and saleratus content is 99.1%, meets national premium grads quality standard.

Adopting the coal consumption (the mark coal calculates) of 1 ton of salt of wormwood of the every production of aforesaid method is 0.684 ton, and power consumption is 226 kilowatt-hours, and the consumption of main raw material Repone K and bicarbonate of ammonia is respectively 1.141 tons and 1.321 tons.

The comparative example

Comparative Examples 1, the saleratus mother liquor that contains salt of wormwood in the potassium bicarbonate solution that contains bicarbonate of ammonia in reservoir (1) and reservoir (2) is mixed and (in mixed material, contains bicarbonate of ammonia 30g/L, contain salt of wormwood 50g/L, contain saleratus 280g/L), the potassium bicarbonate solution of mixture is produced by existing technique (patent of invention CN200810164153.4 is described), the coal consumption of 1 ton of salt of wormwood of every production (the mark coal calculates) is 1.3 tons, power consumption is 270 kilowatt-hours, the consumption of main raw material Repone K and bicarbonate of ammonia is respectively 1.153 tons and 1.335 tons, evaporation gained saleratus median size is less than 1mm, saleratus content on average is less than 99.0%.

Comparative Examples 2, the saleratus mother liquor that contains salt of wormwood in the potassium bicarbonate solution that contains bicarbonate of ammonia in reservoir (1) and reservoir (2) is mixed and (in mixed material, contains bicarbonate of ammonia 30g/L, contain salt of wormwood 50g/L, contain saleratus 280g/L), mixed material is produced by embodiment 3 of the present invention, gained saleratus crystallization mean particle size is greater than 2.0mm, saleratus content is 99.3%, meet national premium grads quality standard, the coal consumption of 1 ton of salt of wormwood of every production (the mark coal calculates) is 0.68 ton, power consumption is 220 kilowatt-hours, the consumption of main raw material Repone K and bicarbonate of ammonia is respectively 1.141 tons and 1.316 tons, comprehensive cost reduces more than 800 yuan than existing production technique.

The processing method of Comparative Examples 3, the described a kind of method for producing potassium carbonate by ion exchange of patent CN200910068696.0, this technique mainly comprises the unit such as desorb, evaporation, absorption, carbonating, crystallization and drying, the concrete technology step is: ion-exchange is decomposed after completing the liquid preheating in desorption tower, then enter triple effect and steam unit, complete evaporation of liquid enters carbon dioxide absorption tower (being to carry out the carbonation reaction of 2-4 hour under 0.4-0.8MPa at pressure), and salt of wormwood is all turned to saleratus by carbonic acid.Carbonating carbon dioxide used is from desorption tower and moisture eliminator, and the ammonia that desorption tower decomposes is absorbed as ammoniacal liquor by the ammonia absorption tower and does dosing and use.The saleratus crystallization is carried out drying again after whizzer dries, salt of wormwood finished product packing warehouse-in.Patent CN200910068696.0 has cancelled existing ash furnace workshop section, reduced environmental pollution, remove non-condensable gases thorough, improved evaporation heat transfer coefficient, carbonic acid gas centralized collection concentration is high, reduces the carbonating time, improved production efficiency, save material, reduce production costs, significantly improved economic benefit and social benefit.

Patent CN200910068696.0 technology is compared with technology of the present invention, they are to adopt following current triple effect evaporation system, vaporization temperature is higher, steam mono-consumption is high, high temperature causes the saleratus of 12.5%-33.8% to be decomposed into salt of wormwood, affects follow-up crystallization and quality product (equipment corrosion increase iron ion content), need to could meet subsequent production by increasing the carbonating operation, therefore extended production process and increased facility investment, energy consumption also significantly increases.And the present invention adopts quadruple effect cross-flow continuous evaporative crystallization, by heat pump, extract end effect secondary steam and give birth to the heating of vapour mixture as the I vaporizer, significantly reduced steam consumption, the present invention simultaneously adopts DBT type continuous evaporating crystallizer, improve the grain size number (the average crystallite granularity is greater than 2mm) of saleratus, adopt low-temperature decomposition from the carbonization technology, reduce the ratio of salt of wormwood in saleratus, improve the quality of products, also cancelled the carbonating operation, the decrease power consumption, shorten the production time (the required carbonating time of the described production salt of wormwood of patent CN200910068696.0 method is 2-4 hour).

According to the described method of CN200910068696.0, the coal consumption of 1 ton of salt of wormwood of every production (the mark coal calculates) is 0.88 ton, power consumption is 290 kilowatt-hours, the consumption of main raw material Repone K and bicarbonate of ammonia is respectively 1.19 tons and 1.38 tons, evaporation gained saleratus median size is less than 2mm, and saleratus content on average is less than 99.1%.

Finally, it is also to be noted that, what more than enumerate is only several specific embodiments of the present invention.Obviously, the invention is not restricted to above embodiment, many distortion can also be arranged.All distortion that those of ordinary skill in the art can directly derive or associate from content disclosed by the invention, all should think protection scope of the present invention.

Claims

1. from carbonization multiple-effect cross-flow continuous evaporative crystallization, produce the method for saleratus, it is characterized in that comprising the following steps successively:

1), setting contains the saleratus ion exchanged soln of bicarbonate of ammonia in reservoir I (1), and the saleratus mother liquor that contains salt of wormwood is set in reservoir II (2);

After the described saleratus ion exchanged soln that contains bicarbonate of ammonia mixes with the saleratus mother liquor that contains salt of wormwood, obtain mixed liquor; Described mixed liquor relies on pump I (3) successively by Verticle pipe steam water of condensation interchanger (4) and plate-type heat exchanger (5), obtains feed liquid after preheating;

In the saleratus ion exchanged soln that contains bicarbonate of ammonia in described reservoir I (1), the concentration of bicarbonate of ammonia is 40-60g/L, and the concentration of saleratus is 220-240g/L;

In the saleratus mother liquor that contains salt of wormwood in described reservoir II (2), the concentration of salt of wormwood is 100-120g/L, the concentration 400-440g/L of saleratus;

Control contains the saleratus ion exchanged soln of bicarbonate of ammonia from the flow velocity flowed out reservoir I (1) and the middle flow velocity flowed out of saleratus mother liquor reservoir II (2) that contains salt of wormwood, thereby the concentration that makes bicarbonate of ammonia in mixed liquor is 20-40g/L, the concentration that contains salt of wormwood is 30-60g/L, and the concentration that contains saleratus is 280-320g/L;

2), after described preheating, feed liquid is sent into desorb through pump II (6) and is carried out low-temperature desorption from carbonization from carbonating tower (7);

3) the feed liquid dependence pump III (8), flowed out from carbonating tower (7) from desorb enters in III single-effect evaporator (9) carries out evaporation concentration;

4), the dependence pump IV of the material after III single-effect evaporator (9) is concentrated (10) is sent in II single-effect evaporator (11) and is carried out evaporation concentration;

5), the dependence pump V of the material after II single-effect evaporator (11) is concentrated (12) is sent in I single-effect evaporator (13) and is carried out evaporation concentration;

6), the material after I single-effect evaporator (13) is concentrated relies on pump VI (14) to send into IV single-effect evaporator (15) and concentrates flash crystallization;

7), the material after IV single-effect evaporator (15) crystallization is transported to cooling crystallizer (17) by pump VII (16) and carries out crystallisation by cooling;

8), the solidliquid mixture after crystallisation by cooling separates by whizzer (18), obtain the saleratus crystallization and contain the saleratus mother liquor of salt of wormwood;

9), packing warehouse-in after the dry screening of saleratus crystal drying device (19); The saleratus mother liquor that contains salt of wormwood is sent into respectively II single-effect evaporator (11) and reservoir II (2) by pump VIII (20).

2. method of producing saleratus from carbonization multiple-effect cross-flow continuous evaporative crystallization according to claim 1 is characterized in that:

The secondary steam that in step 5), I single-effect evaporator (13) produces is as the heating steam of step 4) II single-effect evaporator (11), the secondary steam that step 4) II single-effect evaporator (11) produces is as the heating steam of step 3) III single-effect evaporator (9), and the secondary steam that step 3) III single-effect evaporator (9) produces is as the heating steam of step 6) IV single-effect evaporator (15).

3. method of producing saleratus from carbonization multiple-effect cross-flow continuous evaporative crystallization according to claim 2, it is characterized in that: the secondary steam that in step 6), IV single-effect evaporator (15) produces is divided into 2 parts:

A part extracts with after the middle pressure steam that comes from boiler (24) mixes, as the heating steam of step 5) I single-effect evaporator (13) by heat pump (21); After mixing, Steam pressure control is between 0.004-0.006MPa;

Another part enters vacuum system (23) after condenser (22) is cooling, control IV single-effect evaporator (15) vacuum tightness between negative 0.088-0.092MPa.

4. method of producing saleratus from carbonization multiple-effect cross-flow continuous evaporative crystallization according to claim 3, it is characterized in that: step 2) in desorb from the steam condensate that carbonating tower (7) steam condensate and step 5) I single-effect evaporator (13) produce, return to heat power plant, as boiler (24) feedwater.

5. method of producing saleratus from carbonization multiple-effect cross-flow continuous evaporative crystallization according to claim 4, it is characterized in that: step 2) desorb is connected into the water-circulating pump vacuum system by plate-type heat exchanger (5) and the cold doubtful device of vertical pipe type (27) after cooling successively again from ammonia that carbonating tower (7) bicarbonate of ammonia decompose to produce, by deionized water, absorb ammonia and produce dilute ammonia solution, inhale the weak ammonia and the step 4) II single-effect evaporator (11) that after ammonia, obtain, the steam condensate mixing that step 3) III single-effect evaporator (9) and step 6) IV single-effect evaporator (15) produce is transported to bicarbonate of ammonia dissolving tank (25), as the water that dissolves the bicarbonate of ammonia raw material.

6. method of producing saleratus from carbonization multiple-effect cross-flow continuous evaporative crystallization according to claim 5, it is characterized in that: the secondary steam water of condensation of step 6) IV single-effect evaporator (15) is delivered to ion-exchanger (26), cleans the resin water as ion-exchange process.

7. method of producing saleratus from carbonization multiple-effect cross-flow continuous evaporative crystallization according to claim 6, it is characterized in that: in step 1), mixed liquor is after Verticle pipe steam water of condensation interchanger (4) and board-like tail gas heat exchanger (5) preheating, temperature of charge rises to 50 ℃ by 35 ℃, steam condensate in described Verticle pipe steam water of condensation interchanger (4) is from the steam condensate of desorb from carbonating tower (7) steam condensate and step 5) I single-effect evaporator (13) generation, tail gas in described board-like tail gas heat exchanger (5) decomposes the secondary steam produced from carbonization from carbonating tower (7) from desorb.

8. method of producing saleratus from carbonization multiple-effect cross-flow continuous evaporative crystallization according to claim 7 is characterized in that:

I single-effect evaporator (13) temperature is controlled at 85-87 ℃, and II single-effect evaporator (11) temperature is controlled at 73-75 ℃, and III single-effect evaporator (9) temperature is controlled at 63-65 ℃, and IV single-effect evaporator (15) temperature is controlled at 53-59 ℃;

I single-effect evaporator (13) vacuum degree control is at negative pressure 0.056-0.060MPa, II single-effect evaporator (11) vacuum degree control is at negative pressure 0.070-0.074MPa, III single-effect evaporator (9) vacuum degree control is at negative pressure 0.078-0.082MPa, and IV single-effect evaporator (15) vacuum degree control is at negative pressure 0.088-0.092MPa.

9. method of producing saleratus from carbonization multiple-effect cross-flow continuous evaporative crystallization according to claim 8, it is characterized in that: I single-effect evaporator (13), II single-effect evaporator (11) and III single-effect evaporator (9) are the vertical pipe type falling-film evaporator, and IV single-effect evaporator (15) is DTB type continuous evaporating crystallizer.