CN1793103A - Process for preparing calcium formate from recovered formylic acid in waste water of epoxy soybean oil - Google Patents

Abstract

The invention relates to a method to make calcium formiate from formic acid recycled from epoxidized soybean oil waste water. The method includes the following steps: adding the formic acid waste water into sloping plate oil removal groove to separate most epoxidized soybean oil drop and deposit, the up layer oil drop would be recycled, the down layer of deposit is discharged, and the waste water coming into reactor; controlling the reaction temperature, adding heavy calcium carbonate powder, using Ca(OH)2 emulsion to adjust pH value to 6-8, using Na2S to remove the heavy metal in the solution, removing the solid impurity; vaporizing and crystallizing, separating by centrifuge, drying and the solid calcium formiate would be gained. The invention could realize zero release of waste water and improve the economic benefits.

Description

From epoxy soybean oil waste water, reclaim the method that formic acid is produced calcium formiate

Technical field

The invention belongs in waste water treatment a kind of processing method that reclaims resource, specifically be preparation from the formic acid wastewater of epoxy soybean oil production discharging, concentrate, the method for crystallization purifying calcium formiate.

Background technology

The production of epoxy soybean oil is that to adopt refined soybean oil, formic acid, hydrogen peroxide be raw material, under given conditions, makes the soybean oil epoxidation generate epoxy soybean oil.In process of production, formic acid plays instrumentality in whole epoxy reaction system, and its concentration has taken place significantly to change, and drops to about 8% by original 85%.By analyzing, the waste water index is: pH 3.5～4, and is colourless, contains lipid 500mg/L, and formic acid is about 8%, hydrogen peroxide about 0.9% and a small amount of peroxyformic acid, the on average about 20000mg/L of COD.The acid-bearing wastewater of high COD like this lacks corresponding Technology of Sewage on the one hand, and on the other hand, processing cost is high, and business burden is heavy.So, must look for another way, reclaim the formic acid in the waste water, realize resource utilization, to reduce cost of sewage disposal, realize sewage zero-discharge even.

Calcium formiate is as a kind of novel fodder additive, and is of many uses, and it can replace citric acid, fumaric acid as acidic flavoring agent, can substitute calcium propionate again as anticorrosion and mould inhibitor, be applicable in all kinds of animal-feeds and use to have the diarrhoea of preventing, diarrhea, help feed function such as to digest and assimilate.Especially piglet is had more significant effect, in piglet diet, add calcium formiate 1%～15%, can prevent that diarrhoea and diarrhea from taking place, improve food conversion ratio 7%～10%, feed intake decline 3.8%, the pig body weight 9%～13% that increases day by day.Calcium formiate is in animal body through biochemical action, micro-formic acid can dissociate, reduce the pH value in the gi tract, prevent the growth and breeding of malignant bacteria, still can usefully have a liking for the growth of acids organism of fermentation simultaneously, reach the intrusion that the covering intestinal mucosa is not subjected to toxin, the micro-formic acid that dissociates out can also produce sequestering action with the feed mineral, promote digesting and assimilating of mineral substance, can also play the effect that activates propepsin simultaneously, thus the absorption that has improved feed effective constituent.Calcium formiate also is widely used in being added to the setting rate that can accelerate cement in the cement on the industrial production such as food, chemical industry, building materials, process hides, oil simultaneously except that the extensive application of feedstuff industry, shortens time of coagulation; Calcium formiate also can be made oral preparation, the calcium deficiency of treatment human body, and the medicine of replenishing the calcium on the market, great majority are made with it, and calcium formiate also is better ideal crop growth conditioning agent, can make crop yield about 10%.Because the calcium formiate product performance are good, price is low, the domestic and international market is good at present, and prospect for sales is wide.

Precious far away grade of grandson invented a kind of method (CN1472186) of producing calcium formiate.In this treatment process, is concentration that 8%～30% formic acid adds in the reactor, under constantly stirring be concentration that 95% lime carbonate adds in the reactor, react at a certain temperature after adding lime carbonate, add purity again and be 91% calcium hydroxide and regulate the calcium formiate pH value of water solution that generates, restir for some time finishes reaction; To deliver to the adjustment groove after the filtration of reaction solution process filter, adjust totally two of grooves, adjust the pH value of groove internal reaction liquid respectively, the reaction solution that mixes up the pH value is alternately to the vaporizer feed, brilliant liquid mixture is delivered to the whizzer separation after evaporating, mother liquor returns vaporizer and continues evaporation, and crystal is made calcium formiate after drying.This production method realizes serialization and mass-producing, and the product cost of making is low, and heavy metal ion content reaches the feed grade standard-required.

The present invention proposes preparation from the formic acid wastewater of epoxy soybean oil production discharging, concentrates, the method for purifying calcium formiate, and its purpose is to reclaim resource from sewage disposal, utilize resource, realizes sewage zero-discharge, increases economic efficiency.

Summary of the invention

The scheme that the present invention proposes is: excluding most of epoxy soybean oil oil droplet and throw out in the formic acid wastewater adding inclined plate grease groove of epoxy soybean oil production discharging, the upper strata oil droplet reclaims as product, the discharging of lower sediment thing, and waste water enters in the reactor; The pH of control reaction temperature and solution, the adding particle diameter is the water-ground limestone powder more than 200 orders under constantly stirring, and to pH4.5～5, adds calcium hydroxide emulsion again and comes regulator solution to pH 6～8, adds an amount of Na again ₂S removes the heavy metal in the solution, continues to finish reaction after stirring for some time; Remove the solid impurity more than 100 microns in the reaction solution with the precipitator method, re-use the further solid impurity of removal more than 5 microns of honeycomb filter core or wire-wound filter core; The stillness of night after filtering is delivered to vaporizer carry out evaporative crystallization, brilliant liquid mixture is delivered to the whizzer separation after evaporating, and mother liquor is stored, and goes into evaporation next time, and xln is made solid formic acid calcium behind air stream drying.

This production method realizes the recovery and the reuse of epoxy soybean oil formic acid wastewater, and remarkable in economical benefits, quality product reach the requirement of feed grade calcium formiate.Present method is with sewage treatment process and reclaim resource, utilize resource technology reasonable combination, realizes sewage zero-discharge, improves economic benefit of enterprises.

Method of the present invention comprises the steps:

(1) will produce in the formic acid wastewater adding inclined plate grease groove of epoxy soybean oil discharging, and exclude most of epoxy soybean oil oil droplet and throw out, the upper strata oil droplet reclaims as product, and sediment discharge, waste water enter in the reactor;

(2) control reaction temperature to 30～80 ℃, under agitation condition, in waste water solution, add particle diameter and be the water-ground limestone powder more than 200 orders, after measuring pH to 4.5～5 of solution, add purity again and be 95% calcium hydroxide, regulator solution is to pH 6～8, add 0.5～8L by waste water per ton, adding concentration is the Na of 1～5mol/L ₂S continues to finish reaction behind stirring 10～30min;

(3) remove the solid impurity more than 100 microns in the reaction solution with the precipitator method, re-use the further solid impurity of removal more than 5 microns of honeycomb filter core or wire-wound filter core;

(4) stillness of night after will filtering is delivered to vaporizer and carries out evaporative crystallization, and the brilliant liquid mixture after the evaporation is separated with whizzer, collects mother liquor, goes into evaporation next time, and centrifugal gained crystal obtains solid formic acid calcium behind air stream drying.

Its formic acid concn of the formic acid wastewater that discharges in the epoxy soybean oil production in present method is 5%～15%.

Adding particle diameter in present method is above its calcium carbonate content of water-ground limestone powder 〉=95% of 200 orders, heavy metal (in Pb)≤0.002%, Mg content≤2%, hydrochloric acid insoluble substance≤0.5%, arsenic (AS)≤0.002%).

Description of drawings

Fig. 1 is a calcium formiate method waste water reclamation main technique schema.

Embodiment

Below the water quality of formic acid wastewater of the used epoxy soybean oil production of two routine embodiment discharging as shown in table 1:

Table 1 waste water quality

Title	Concentration
		Formic acid	5～15％
Hydrogen peroxide	0.9％
		Lipid	500mg/L
CODcr	20000mg/L
		pH	3.5～4
Color	Colourless

Embodiment one:

The raw material waste water of 1 ton of water quality as described in Table 1 is added in the inclined plate grease groove (hydraulic detention time 1h), exclude 99% epoxy soybean oil oil droplet, the upper strata oil droplet reclaims as product, and sediment discharge, waste water enter in the reactor; The pH of control reaction temperature (30 ℃) and solution, in 1h, (calcium carbonate content 〉=95%, particle diameter are 200 orders to the water-ground limestone powder of even about 80kg of adding, heavy metal (in Pb)≤0.002% under constantly stirring, Mg content≤2%, hydrochloric acid insoluble substance≤0.5%, arsenic (AS)≤0.002%), to pH 5, add purity again and be 95% the about 10kg regulator solution of calcium hydroxide to pH 7, add the Na that 1～4L concentration is 2mol/L again ₂S continues to finish reaction behind the stirring 10min; Remove the solid impurity more than 100 microns in the reaction solution behind the precipitation 2h, re-use the further solid impurity of removal more than 5 microns of honeycomb filter core or wire-wound filter core; The stillness of night after filtering is delivered to vaporizer carries out evaporative crystallization (to brilliant skin occurring), be cooled to room temperature after, brilliant liquid mixture is delivered to whizzer separates, mother liquor is stored, go into evaporative crystallization next time, xln is made calcium formiate behind air stream drying, and product reaches table 2 requirement.

In the entire treatment process, only discharge 2 tons of evaporation condensed waters (CODcr＜20mg/L), do not have other discharge of wastewater.

Table 2 calcium formiate quality product

Index name	Desired value
		Outward appearance	White
Calcium formiate content (%)	≥98％
		Heavy metal (in Pb)	≤0.002％
Arsenic (AS)	≤0.002％
		Weight loss on drying	≤1.0％
Water-insoluble	≤0.2％

Embodiment two:

The raw material waste water of 1 ton of water quality as described in Table 1 is added in the inclined plate grease groove (hydraulic detention time 3h), exclude 99.5% epoxy soybean oil oil droplet, the upper strata oil droplet reclaims as product, and sediment discharge, waste water enter in the reactor; The pH of control reaction temperature (50 ℃) and solution, in 2h, (calcium carbonate content 〉=95%, particle diameter are 300 orders to the water-ground limestone powder of even about 75kg of adding, heavy metal (in Pb)≤0.002% under constantly stirring, Mg content≤2%, hydrochloric acid insoluble substance≤0.5%, arsenic (AS)≤0.002%), to pH 4.5, add purity again and be 95% the about 15kg regulator solution of calcium hydroxide to pH 7, add the Na that 0.5～1L concentration is 5mol/L again ₂S continues to finish reaction behind the stirring 30min; Remove the solid impurity more than 100 microns in the reaction solution behind the precipitation 4h, re-use the further solid impurity of removal more than 5 microns of honeycomb filter core or wire-wound filter core; The stillness of night after filtering is delivered to vaporizer carries out evaporative crystallization (to brilliant skin occurring), be cooled to room temperature after, brilliant liquid mixture is delivered to whizzer separates, mother liquor is stored, go into evaporative crystallization next time, xln is made calcium formiate behind air stream drying, and product reaches table 3 requirement.

In the entire treatment process, only discharge 2 tons of evaporation condensed waters (CODcr＜20mg/L), do not have other discharge of wastewater.

Table 3 calcium formiate quality product

Index name	Desired value
		Outward appearance	White
Calcium formiate content (%)	≥98.5％
		Heavy metal (in Pb)	≤0.002％
Arsenic (AS)	≤0.002％
		Weight loss on drying	≤1.0％

Water-insoluble

≤0.2％

Engineering construction example: 10000t/a epoxy soybean oil formic acid wastewater reuse project

It is raw material that refined soybean oil, formic acid, hydrogen peroxide are adopted in the production of certain factory's epoxy soybean oil, and epoxidation 9h gets the epoxy soybean oil production in reactor.This factory produces epoxy soybean oil 7000t per year, and discharging contains calculates waste water 10000t/a (on average about 40t/d), and water quality is: pH 3.5, and is colourless, contains lipid 1000mg/L, and formic acid 8-12%, hydrogen peroxide are about 1.2%, the on average about 25000mg/L of COD.

1. technical process

Certain 10000t/a epoxy soybean oil formic acid wastewater reuse project as shown in Figure 1.

1.1 the pre-treatment of waste water

Use 2t/h, the water pump of 30m lift pumps into the formic acid wastewater (formic acid concn is 8%) of epoxy soybean oil production discharging in the inclined plate grease groove (hydraulic detention time 1.5h), excludes 99% epoxy soybean oil oil droplet, and the upper strata oil droplet reclaims as product, sediment discharge, waste water enters in the reactor.

1.2 reaction

At volume is in the enamel reaction still of 10t, the pH of control reaction temperature (50 ℃) and solution in 1.5h, evenly adds water-ground limestone powder (calcium carbonate content 〉=95% of about 800kg under constantly stirring, particle diameter is 200 orders, heavy metal (in Pb)≤0.002%, Mg content≤2%, hydrochloric acid insoluble substance≤0.5%, arsenic (AS)≤0.002%), to pH 5, add purity again and be 98% the about 90kg of calcium hydroxide and come regulator solution to pH 7, add the Na that 5～8L concentration is 5mol/L again ₂S continues to finish reaction behind the stirring 1h.

1.3 the removal of impurity

Precipitation (hydraulic detention time 2h) in the swash plate settling pond pumps into the honeycomb candle filter with the water pump of 2t/h, 40m lift with primary water.

1.4 evaporative crystallization and oven dry

Delivered to the 2nd effect evaporator of 2t/h the stillness of night after filtering, being concentrated to calcium formiate content is about 60%, in volume is the evaporating kettle of 5t, lead to steam and carry out evaporative crystallization, occur brilliant skin behind about 4h, cooling will evaporate the brilliant liquid mixture in back and be delivered to tripod pendulum type batch centrifugal and dewater that (the filter cloth model is a terylene plain weave 260, centrifuge dehydration time 15min), mother liquor is stored, and goes into evaporative crystallization next time, wet feed water content≤5%.

Crystal is through tubular type pneumatic dryer (caliber φ 300mm, pipe range 20m, air quantity 3000m ³/ h, 150～180 ℃ of drying temperatures) after the drying the product calcium formiate.The calcium formiate product reaches the specification of quality of table 2.

2. equipment

Required major equipment sees Table 4.About 400,000 yuan of facility investment, floor space 80m ²

Table 4 calcium formiate method major equipment table look-up

Sequence number	Device name	Specification	The platform number	Remarks
					1	The inclined plate grease groove	2t/h	1	PVC
2	Reactor	10t	1	Enamel
					3	The swash plate settling pond	2t/h	1	PVC
4	The honeycomb candle filter	2t/h	1	SS
					5	2nd effect evaporator	2t/h	1	SS
6	Evaporating kettle	5t	1	Chuck, enamel
					7	Tripod pendulum type batch centrifugal	Terylene plain weave 260	1	SS
8	Pneumatic dryer	φ300	1	SS
					9	Water pump		2	SS

3. cost keeping

1t contains 8% formic acid wastewater calcium formiate method processing cost and saw Table for 5 (containing formic acid 8% waste water to reclaim 1 ton).

Table 5 calcium formiate method cost for wastewater treatment table

Sequence number	Project	Consumption	The amount of money (unit)
				1	Water-ground limestone	80kg	-28
2	Conditioning agent	5kg	-2
				3	Precipitation agent	1kg	-5
4	Electricity	30 degree	-30
				5	Packing	5	-20
6	Wage and welfare		-15
				7	Depreciation		-5
8	Steam consumption (2nd effect evaporator)	0.6t	-69
					Processing cost adds up to		-174
	Reclaim calcium formiate	96kg	460
					Handle income		286

As seen from table, the waste water of 10000t/a its to reclaim economic direct benefit be 2,860,000 yuan, save nearly 1,000,000 yuan of cost of sewage disposal simultaneously, can be enterprise and bring 3,860,000 yuan of direct economic benefits, the remarkable in economical benefits of this method.

Claims (1)

1, from epoxy soybean oil waste water, reclaim the method that formic acid is produced calcium formiate, it is characterized in that following step:

(1) will produce in the formic acid wastewater adding inclined plate grease groove of epoxy soybean oil discharging, and exclude most of epoxy soybean oil oil droplet and throw out, the upper strata oil droplet reclaims as product, and sediment discharge, waste water enter in the reactor;

(2) control reaction temperature to 30～80 ℃, under agitation condition, in waste water solution, add particle diameter and be the water-ground limestone powder more than 200 orders, after measuring pH to 4.5～5 of solution, add purity again and be 95% calcium hydroxide, regulator solution is to pH 6～8, add 0.5～8L by waste water per ton, adding concentration is the Na of 1～5mol/L ₂S continues to finish reaction behind stirring 10～30min;

(3) remove the solid impurity more than 100 microns in the reaction solution with the precipitator method, re-use the further solid impurity of removal more than 5 microns of honeycomb filter core or wire-wound filter core;

(4) stillness of night after will filtering is delivered to vaporizer and carries out evaporative crystallization, and the brilliant liquid mixture after the evaporation is separated with whizzer, collects mother liquor, goes into evaporation next time, and centrifugal gained crystal obtains solid formic acid calcium behind air stream drying.